config: add git_config_get_expiry() from gc.c
[git] / apply.c
1 /*
2  * apply.c
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  *
6  * This applies patches on top of some (arbitrary) version of the SCM.
7  *
8  */
9
10 #include "cache.h"
11 #include "blob.h"
12 #include "delta.h"
13 #include "diff.h"
14 #include "dir.h"
15 #include "xdiff-interface.h"
16 #include "ll-merge.h"
17 #include "lockfile.h"
18 #include "parse-options.h"
19 #include "quote.h"
20 #include "rerere.h"
21 #include "apply.h"
22
23 static void git_apply_config(void)
24 {
25         git_config_get_string_const("apply.whitespace", &apply_default_whitespace);
26         git_config_get_string_const("apply.ignorewhitespace", &apply_default_ignorewhitespace);
27         git_config(git_default_config, NULL);
28 }
29
30 static int parse_whitespace_option(struct apply_state *state, const char *option)
31 {
32         if (!option) {
33                 state->ws_error_action = warn_on_ws_error;
34                 return 0;
35         }
36         if (!strcmp(option, "warn")) {
37                 state->ws_error_action = warn_on_ws_error;
38                 return 0;
39         }
40         if (!strcmp(option, "nowarn")) {
41                 state->ws_error_action = nowarn_ws_error;
42                 return 0;
43         }
44         if (!strcmp(option, "error")) {
45                 state->ws_error_action = die_on_ws_error;
46                 return 0;
47         }
48         if (!strcmp(option, "error-all")) {
49                 state->ws_error_action = die_on_ws_error;
50                 state->squelch_whitespace_errors = 0;
51                 return 0;
52         }
53         if (!strcmp(option, "strip") || !strcmp(option, "fix")) {
54                 state->ws_error_action = correct_ws_error;
55                 return 0;
56         }
57         return error(_("unrecognized whitespace option '%s'"), option);
58 }
59
60 static int parse_ignorewhitespace_option(struct apply_state *state,
61                                                  const char *option)
62 {
63         if (!option || !strcmp(option, "no") ||
64             !strcmp(option, "false") || !strcmp(option, "never") ||
65             !strcmp(option, "none")) {
66                 state->ws_ignore_action = ignore_ws_none;
67                 return 0;
68         }
69         if (!strcmp(option, "change")) {
70                 state->ws_ignore_action = ignore_ws_change;
71                 return 0;
72         }
73         return error(_("unrecognized whitespace ignore option '%s'"), option);
74 }
75
76 int init_apply_state(struct apply_state *state,
77                      const char *prefix,
78                      struct lock_file *lock_file)
79 {
80         memset(state, 0, sizeof(*state));
81         state->prefix = prefix;
82         state->prefix_length = state->prefix ? strlen(state->prefix) : 0;
83         state->lock_file = lock_file;
84         state->newfd = -1;
85         state->apply = 1;
86         state->line_termination = '\n';
87         state->p_value = 1;
88         state->p_context = UINT_MAX;
89         state->squelch_whitespace_errors = 5;
90         state->ws_error_action = warn_on_ws_error;
91         state->ws_ignore_action = ignore_ws_none;
92         state->linenr = 1;
93         string_list_init(&state->fn_table, 0);
94         string_list_init(&state->limit_by_name, 0);
95         string_list_init(&state->symlink_changes, 0);
96         strbuf_init(&state->root, 0);
97
98         git_apply_config();
99         if (apply_default_whitespace && parse_whitespace_option(state, apply_default_whitespace))
100                 return -1;
101         if (apply_default_ignorewhitespace && parse_ignorewhitespace_option(state, apply_default_ignorewhitespace))
102                 return -1;
103         return 0;
104 }
105
106 void clear_apply_state(struct apply_state *state)
107 {
108         string_list_clear(&state->limit_by_name, 0);
109         string_list_clear(&state->symlink_changes, 0);
110         strbuf_release(&state->root);
111
112         /* &state->fn_table is cleared at the end of apply_patch() */
113 }
114
115 static void mute_routine(const char *msg, va_list params)
116 {
117         /* do nothing */
118 }
119
120 int check_apply_state(struct apply_state *state, int force_apply)
121 {
122         int is_not_gitdir = !startup_info->have_repository;
123
124         if (state->apply_with_reject && state->threeway)
125                 return error(_("--reject and --3way cannot be used together."));
126         if (state->cached && state->threeway)
127                 return error(_("--cached and --3way cannot be used together."));
128         if (state->threeway) {
129                 if (is_not_gitdir)
130                         return error(_("--3way outside a repository"));
131                 state->check_index = 1;
132         }
133         if (state->apply_with_reject) {
134                 state->apply = 1;
135                 if (state->apply_verbosity == verbosity_normal)
136                         state->apply_verbosity = verbosity_verbose;
137         }
138         if (!force_apply && (state->diffstat || state->numstat || state->summary || state->check || state->fake_ancestor))
139                 state->apply = 0;
140         if (state->check_index && is_not_gitdir)
141                 return error(_("--index outside a repository"));
142         if (state->cached) {
143                 if (is_not_gitdir)
144                         return error(_("--cached outside a repository"));
145                 state->check_index = 1;
146         }
147         if (state->check_index)
148                 state->unsafe_paths = 0;
149         if (!state->lock_file)
150                 return error("BUG: state->lock_file should not be NULL");
151
152         if (state->apply_verbosity <= verbosity_silent) {
153                 state->saved_error_routine = get_error_routine();
154                 state->saved_warn_routine = get_warn_routine();
155                 set_error_routine(mute_routine);
156                 set_warn_routine(mute_routine);
157         }
158
159         return 0;
160 }
161
162 static void set_default_whitespace_mode(struct apply_state *state)
163 {
164         if (!state->whitespace_option && !apply_default_whitespace)
165                 state->ws_error_action = (state->apply ? warn_on_ws_error : nowarn_ws_error);
166 }
167
168 /*
169  * This represents one "hunk" from a patch, starting with
170  * "@@ -oldpos,oldlines +newpos,newlines @@" marker.  The
171  * patch text is pointed at by patch, and its byte length
172  * is stored in size.  leading and trailing are the number
173  * of context lines.
174  */
175 struct fragment {
176         unsigned long leading, trailing;
177         unsigned long oldpos, oldlines;
178         unsigned long newpos, newlines;
179         /*
180          * 'patch' is usually borrowed from buf in apply_patch(),
181          * but some codepaths store an allocated buffer.
182          */
183         const char *patch;
184         unsigned free_patch:1,
185                 rejected:1;
186         int size;
187         int linenr;
188         struct fragment *next;
189 };
190
191 /*
192  * When dealing with a binary patch, we reuse "leading" field
193  * to store the type of the binary hunk, either deflated "delta"
194  * or deflated "literal".
195  */
196 #define binary_patch_method leading
197 #define BINARY_DELTA_DEFLATED   1
198 #define BINARY_LITERAL_DEFLATED 2
199
200 /*
201  * This represents a "patch" to a file, both metainfo changes
202  * such as creation/deletion, filemode and content changes represented
203  * as a series of fragments.
204  */
205 struct patch {
206         char *new_name, *old_name, *def_name;
207         unsigned int old_mode, new_mode;
208         int is_new, is_delete;  /* -1 = unknown, 0 = false, 1 = true */
209         int rejected;
210         unsigned ws_rule;
211         int lines_added, lines_deleted;
212         int score;
213         unsigned int is_toplevel_relative:1;
214         unsigned int inaccurate_eof:1;
215         unsigned int is_binary:1;
216         unsigned int is_copy:1;
217         unsigned int is_rename:1;
218         unsigned int recount:1;
219         unsigned int conflicted_threeway:1;
220         unsigned int direct_to_threeway:1;
221         struct fragment *fragments;
222         char *result;
223         size_t resultsize;
224         char old_sha1_prefix[41];
225         char new_sha1_prefix[41];
226         struct patch *next;
227
228         /* three-way fallback result */
229         struct object_id threeway_stage[3];
230 };
231
232 static void free_fragment_list(struct fragment *list)
233 {
234         while (list) {
235                 struct fragment *next = list->next;
236                 if (list->free_patch)
237                         free((char *)list->patch);
238                 free(list);
239                 list = next;
240         }
241 }
242
243 static void free_patch(struct patch *patch)
244 {
245         free_fragment_list(patch->fragments);
246         free(patch->def_name);
247         free(patch->old_name);
248         free(patch->new_name);
249         free(patch->result);
250         free(patch);
251 }
252
253 static void free_patch_list(struct patch *list)
254 {
255         while (list) {
256                 struct patch *next = list->next;
257                 free_patch(list);
258                 list = next;
259         }
260 }
261
262 /*
263  * A line in a file, len-bytes long (includes the terminating LF,
264  * except for an incomplete line at the end if the file ends with
265  * one), and its contents hashes to 'hash'.
266  */
267 struct line {
268         size_t len;
269         unsigned hash : 24;
270         unsigned flag : 8;
271 #define LINE_COMMON     1
272 #define LINE_PATCHED    2
273 };
274
275 /*
276  * This represents a "file", which is an array of "lines".
277  */
278 struct image {
279         char *buf;
280         size_t len;
281         size_t nr;
282         size_t alloc;
283         struct line *line_allocated;
284         struct line *line;
285 };
286
287 static uint32_t hash_line(const char *cp, size_t len)
288 {
289         size_t i;
290         uint32_t h;
291         for (i = 0, h = 0; i < len; i++) {
292                 if (!isspace(cp[i])) {
293                         h = h * 3 + (cp[i] & 0xff);
294                 }
295         }
296         return h;
297 }
298
299 /*
300  * Compare lines s1 of length n1 and s2 of length n2, ignoring
301  * whitespace difference. Returns 1 if they match, 0 otherwise
302  */
303 static int fuzzy_matchlines(const char *s1, size_t n1,
304                             const char *s2, size_t n2)
305 {
306         const char *last1 = s1 + n1 - 1;
307         const char *last2 = s2 + n2 - 1;
308         int result = 0;
309
310         /* ignore line endings */
311         while ((*last1 == '\r') || (*last1 == '\n'))
312                 last1--;
313         while ((*last2 == '\r') || (*last2 == '\n'))
314                 last2--;
315
316         /* skip leading whitespaces, if both begin with whitespace */
317         if (s1 <= last1 && s2 <= last2 && isspace(*s1) && isspace(*s2)) {
318                 while (isspace(*s1) && (s1 <= last1))
319                         s1++;
320                 while (isspace(*s2) && (s2 <= last2))
321                         s2++;
322         }
323         /* early return if both lines are empty */
324         if ((s1 > last1) && (s2 > last2))
325                 return 1;
326         while (!result) {
327                 result = *s1++ - *s2++;
328                 /*
329                  * Skip whitespace inside. We check for whitespace on
330                  * both buffers because we don't want "a b" to match
331                  * "ab"
332                  */
333                 if (isspace(*s1) && isspace(*s2)) {
334                         while (isspace(*s1) && s1 <= last1)
335                                 s1++;
336                         while (isspace(*s2) && s2 <= last2)
337                                 s2++;
338                 }
339                 /*
340                  * If we reached the end on one side only,
341                  * lines don't match
342                  */
343                 if (
344                     ((s2 > last2) && (s1 <= last1)) ||
345                     ((s1 > last1) && (s2 <= last2)))
346                         return 0;
347                 if ((s1 > last1) && (s2 > last2))
348                         break;
349         }
350
351         return !result;
352 }
353
354 static void add_line_info(struct image *img, const char *bol, size_t len, unsigned flag)
355 {
356         ALLOC_GROW(img->line_allocated, img->nr + 1, img->alloc);
357         img->line_allocated[img->nr].len = len;
358         img->line_allocated[img->nr].hash = hash_line(bol, len);
359         img->line_allocated[img->nr].flag = flag;
360         img->nr++;
361 }
362
363 /*
364  * "buf" has the file contents to be patched (read from various sources).
365  * attach it to "image" and add line-based index to it.
366  * "image" now owns the "buf".
367  */
368 static void prepare_image(struct image *image, char *buf, size_t len,
369                           int prepare_linetable)
370 {
371         const char *cp, *ep;
372
373         memset(image, 0, sizeof(*image));
374         image->buf = buf;
375         image->len = len;
376
377         if (!prepare_linetable)
378                 return;
379
380         ep = image->buf + image->len;
381         cp = image->buf;
382         while (cp < ep) {
383                 const char *next;
384                 for (next = cp; next < ep && *next != '\n'; next++)
385                         ;
386                 if (next < ep)
387                         next++;
388                 add_line_info(image, cp, next - cp, 0);
389                 cp = next;
390         }
391         image->line = image->line_allocated;
392 }
393
394 static void clear_image(struct image *image)
395 {
396         free(image->buf);
397         free(image->line_allocated);
398         memset(image, 0, sizeof(*image));
399 }
400
401 /* fmt must contain _one_ %s and no other substitution */
402 static void say_patch_name(FILE *output, const char *fmt, struct patch *patch)
403 {
404         struct strbuf sb = STRBUF_INIT;
405
406         if (patch->old_name && patch->new_name &&
407             strcmp(patch->old_name, patch->new_name)) {
408                 quote_c_style(patch->old_name, &sb, NULL, 0);
409                 strbuf_addstr(&sb, " => ");
410                 quote_c_style(patch->new_name, &sb, NULL, 0);
411         } else {
412                 const char *n = patch->new_name;
413                 if (!n)
414                         n = patch->old_name;
415                 quote_c_style(n, &sb, NULL, 0);
416         }
417         fprintf(output, fmt, sb.buf);
418         fputc('\n', output);
419         strbuf_release(&sb);
420 }
421
422 #define SLOP (16)
423
424 static int read_patch_file(struct strbuf *sb, int fd)
425 {
426         if (strbuf_read(sb, fd, 0) < 0)
427                 return error_errno("git apply: failed to read");
428
429         /*
430          * Make sure that we have some slop in the buffer
431          * so that we can do speculative "memcmp" etc, and
432          * see to it that it is NUL-filled.
433          */
434         strbuf_grow(sb, SLOP);
435         memset(sb->buf + sb->len, 0, SLOP);
436         return 0;
437 }
438
439 static unsigned long linelen(const char *buffer, unsigned long size)
440 {
441         unsigned long len = 0;
442         while (size--) {
443                 len++;
444                 if (*buffer++ == '\n')
445                         break;
446         }
447         return len;
448 }
449
450 static int is_dev_null(const char *str)
451 {
452         return skip_prefix(str, "/dev/null", &str) && isspace(*str);
453 }
454
455 #define TERM_SPACE      1
456 #define TERM_TAB        2
457
458 static int name_terminate(int c, int terminate)
459 {
460         if (c == ' ' && !(terminate & TERM_SPACE))
461                 return 0;
462         if (c == '\t' && !(terminate & TERM_TAB))
463                 return 0;
464
465         return 1;
466 }
467
468 /* remove double slashes to make --index work with such filenames */
469 static char *squash_slash(char *name)
470 {
471         int i = 0, j = 0;
472
473         if (!name)
474                 return NULL;
475
476         while (name[i]) {
477                 if ((name[j++] = name[i++]) == '/')
478                         while (name[i] == '/')
479                                 i++;
480         }
481         name[j] = '\0';
482         return name;
483 }
484
485 static char *find_name_gnu(struct apply_state *state,
486                            const char *line,
487                            const char *def,
488                            int p_value)
489 {
490         struct strbuf name = STRBUF_INIT;
491         char *cp;
492
493         /*
494          * Proposed "new-style" GNU patch/diff format; see
495          * http://marc.info/?l=git&m=112927316408690&w=2
496          */
497         if (unquote_c_style(&name, line, NULL)) {
498                 strbuf_release(&name);
499                 return NULL;
500         }
501
502         for (cp = name.buf; p_value; p_value--) {
503                 cp = strchr(cp, '/');
504                 if (!cp) {
505                         strbuf_release(&name);
506                         return NULL;
507                 }
508                 cp++;
509         }
510
511         strbuf_remove(&name, 0, cp - name.buf);
512         if (state->root.len)
513                 strbuf_insert(&name, 0, state->root.buf, state->root.len);
514         return squash_slash(strbuf_detach(&name, NULL));
515 }
516
517 static size_t sane_tz_len(const char *line, size_t len)
518 {
519         const char *tz, *p;
520
521         if (len < strlen(" +0500") || line[len-strlen(" +0500")] != ' ')
522                 return 0;
523         tz = line + len - strlen(" +0500");
524
525         if (tz[1] != '+' && tz[1] != '-')
526                 return 0;
527
528         for (p = tz + 2; p != line + len; p++)
529                 if (!isdigit(*p))
530                         return 0;
531
532         return line + len - tz;
533 }
534
535 static size_t tz_with_colon_len(const char *line, size_t len)
536 {
537         const char *tz, *p;
538
539         if (len < strlen(" +08:00") || line[len - strlen(":00")] != ':')
540                 return 0;
541         tz = line + len - strlen(" +08:00");
542
543         if (tz[0] != ' ' || (tz[1] != '+' && tz[1] != '-'))
544                 return 0;
545         p = tz + 2;
546         if (!isdigit(*p++) || !isdigit(*p++) || *p++ != ':' ||
547             !isdigit(*p++) || !isdigit(*p++))
548                 return 0;
549
550         return line + len - tz;
551 }
552
553 static size_t date_len(const char *line, size_t len)
554 {
555         const char *date, *p;
556
557         if (len < strlen("72-02-05") || line[len-strlen("-05")] != '-')
558                 return 0;
559         p = date = line + len - strlen("72-02-05");
560
561         if (!isdigit(*p++) || !isdigit(*p++) || *p++ != '-' ||
562             !isdigit(*p++) || !isdigit(*p++) || *p++ != '-' ||
563             !isdigit(*p++) || !isdigit(*p++))   /* Not a date. */
564                 return 0;
565
566         if (date - line >= strlen("19") &&
567             isdigit(date[-1]) && isdigit(date[-2]))     /* 4-digit year */
568                 date -= strlen("19");
569
570         return line + len - date;
571 }
572
573 static size_t short_time_len(const char *line, size_t len)
574 {
575         const char *time, *p;
576
577         if (len < strlen(" 07:01:32") || line[len-strlen(":32")] != ':')
578                 return 0;
579         p = time = line + len - strlen(" 07:01:32");
580
581         /* Permit 1-digit hours? */
582         if (*p++ != ' ' ||
583             !isdigit(*p++) || !isdigit(*p++) || *p++ != ':' ||
584             !isdigit(*p++) || !isdigit(*p++) || *p++ != ':' ||
585             !isdigit(*p++) || !isdigit(*p++))   /* Not a time. */
586                 return 0;
587
588         return line + len - time;
589 }
590
591 static size_t fractional_time_len(const char *line, size_t len)
592 {
593         const char *p;
594         size_t n;
595
596         /* Expected format: 19:41:17.620000023 */
597         if (!len || !isdigit(line[len - 1]))
598                 return 0;
599         p = line + len - 1;
600
601         /* Fractional seconds. */
602         while (p > line && isdigit(*p))
603                 p--;
604         if (*p != '.')
605                 return 0;
606
607         /* Hours, minutes, and whole seconds. */
608         n = short_time_len(line, p - line);
609         if (!n)
610                 return 0;
611
612         return line + len - p + n;
613 }
614
615 static size_t trailing_spaces_len(const char *line, size_t len)
616 {
617         const char *p;
618
619         /* Expected format: ' ' x (1 or more)  */
620         if (!len || line[len - 1] != ' ')
621                 return 0;
622
623         p = line + len;
624         while (p != line) {
625                 p--;
626                 if (*p != ' ')
627                         return line + len - (p + 1);
628         }
629
630         /* All spaces! */
631         return len;
632 }
633
634 static size_t diff_timestamp_len(const char *line, size_t len)
635 {
636         const char *end = line + len;
637         size_t n;
638
639         /*
640          * Posix: 2010-07-05 19:41:17
641          * GNU: 2010-07-05 19:41:17.620000023 -0500
642          */
643
644         if (!isdigit(end[-1]))
645                 return 0;
646
647         n = sane_tz_len(line, end - line);
648         if (!n)
649                 n = tz_with_colon_len(line, end - line);
650         end -= n;
651
652         n = short_time_len(line, end - line);
653         if (!n)
654                 n = fractional_time_len(line, end - line);
655         end -= n;
656
657         n = date_len(line, end - line);
658         if (!n) /* No date.  Too bad. */
659                 return 0;
660         end -= n;
661
662         if (end == line)        /* No space before date. */
663                 return 0;
664         if (end[-1] == '\t') {  /* Success! */
665                 end--;
666                 return line + len - end;
667         }
668         if (end[-1] != ' ')     /* No space before date. */
669                 return 0;
670
671         /* Whitespace damage. */
672         end -= trailing_spaces_len(line, end - line);
673         return line + len - end;
674 }
675
676 static char *find_name_common(struct apply_state *state,
677                               const char *line,
678                               const char *def,
679                               int p_value,
680                               const char *end,
681                               int terminate)
682 {
683         int len;
684         const char *start = NULL;
685
686         if (p_value == 0)
687                 start = line;
688         while (line != end) {
689                 char c = *line;
690
691                 if (!end && isspace(c)) {
692                         if (c == '\n')
693                                 break;
694                         if (name_terminate(c, terminate))
695                                 break;
696                 }
697                 line++;
698                 if (c == '/' && !--p_value)
699                         start = line;
700         }
701         if (!start)
702                 return squash_slash(xstrdup_or_null(def));
703         len = line - start;
704         if (!len)
705                 return squash_slash(xstrdup_or_null(def));
706
707         /*
708          * Generally we prefer the shorter name, especially
709          * if the other one is just a variation of that with
710          * something else tacked on to the end (ie "file.orig"
711          * or "file~").
712          */
713         if (def) {
714                 int deflen = strlen(def);
715                 if (deflen < len && !strncmp(start, def, deflen))
716                         return squash_slash(xstrdup(def));
717         }
718
719         if (state->root.len) {
720                 char *ret = xstrfmt("%s%.*s", state->root.buf, len, start);
721                 return squash_slash(ret);
722         }
723
724         return squash_slash(xmemdupz(start, len));
725 }
726
727 static char *find_name(struct apply_state *state,
728                        const char *line,
729                        char *def,
730                        int p_value,
731                        int terminate)
732 {
733         if (*line == '"') {
734                 char *name = find_name_gnu(state, line, def, p_value);
735                 if (name)
736                         return name;
737         }
738
739         return find_name_common(state, line, def, p_value, NULL, terminate);
740 }
741
742 static char *find_name_traditional(struct apply_state *state,
743                                    const char *line,
744                                    char *def,
745                                    int p_value)
746 {
747         size_t len;
748         size_t date_len;
749
750         if (*line == '"') {
751                 char *name = find_name_gnu(state, line, def, p_value);
752                 if (name)
753                         return name;
754         }
755
756         len = strchrnul(line, '\n') - line;
757         date_len = diff_timestamp_len(line, len);
758         if (!date_len)
759                 return find_name_common(state, line, def, p_value, NULL, TERM_TAB);
760         len -= date_len;
761
762         return find_name_common(state, line, def, p_value, line + len, 0);
763 }
764
765 static int count_slashes(const char *cp)
766 {
767         int cnt = 0;
768         char ch;
769
770         while ((ch = *cp++))
771                 if (ch == '/')
772                         cnt++;
773         return cnt;
774 }
775
776 /*
777  * Given the string after "--- " or "+++ ", guess the appropriate
778  * p_value for the given patch.
779  */
780 static int guess_p_value(struct apply_state *state, const char *nameline)
781 {
782         char *name, *cp;
783         int val = -1;
784
785         if (is_dev_null(nameline))
786                 return -1;
787         name = find_name_traditional(state, nameline, NULL, 0);
788         if (!name)
789                 return -1;
790         cp = strchr(name, '/');
791         if (!cp)
792                 val = 0;
793         else if (state->prefix) {
794                 /*
795                  * Does it begin with "a/$our-prefix" and such?  Then this is
796                  * very likely to apply to our directory.
797                  */
798                 if (!strncmp(name, state->prefix, state->prefix_length))
799                         val = count_slashes(state->prefix);
800                 else {
801                         cp++;
802                         if (!strncmp(cp, state->prefix, state->prefix_length))
803                                 val = count_slashes(state->prefix) + 1;
804                 }
805         }
806         free(name);
807         return val;
808 }
809
810 /*
811  * Does the ---/+++ line have the POSIX timestamp after the last HT?
812  * GNU diff puts epoch there to signal a creation/deletion event.  Is
813  * this such a timestamp?
814  */
815 static int has_epoch_timestamp(const char *nameline)
816 {
817         /*
818          * We are only interested in epoch timestamp; any non-zero
819          * fraction cannot be one, hence "(\.0+)?" in the regexp below.
820          * For the same reason, the date must be either 1969-12-31 or
821          * 1970-01-01, and the seconds part must be "00".
822          */
823         const char stamp_regexp[] =
824                 "^(1969-12-31|1970-01-01)"
825                 " "
826                 "[0-2][0-9]:[0-5][0-9]:00(\\.0+)?"
827                 " "
828                 "([-+][0-2][0-9]:?[0-5][0-9])\n";
829         const char *timestamp = NULL, *cp, *colon;
830         static regex_t *stamp;
831         regmatch_t m[10];
832         int zoneoffset;
833         int hourminute;
834         int status;
835
836         for (cp = nameline; *cp != '\n'; cp++) {
837                 if (*cp == '\t')
838                         timestamp = cp + 1;
839         }
840         if (!timestamp)
841                 return 0;
842         if (!stamp) {
843                 stamp = xmalloc(sizeof(*stamp));
844                 if (regcomp(stamp, stamp_regexp, REG_EXTENDED)) {
845                         warning(_("Cannot prepare timestamp regexp %s"),
846                                 stamp_regexp);
847                         return 0;
848                 }
849         }
850
851         status = regexec(stamp, timestamp, ARRAY_SIZE(m), m, 0);
852         if (status) {
853                 if (status != REG_NOMATCH)
854                         warning(_("regexec returned %d for input: %s"),
855                                 status, timestamp);
856                 return 0;
857         }
858
859         zoneoffset = strtol(timestamp + m[3].rm_so + 1, (char **) &colon, 10);
860         if (*colon == ':')
861                 zoneoffset = zoneoffset * 60 + strtol(colon + 1, NULL, 10);
862         else
863                 zoneoffset = (zoneoffset / 100) * 60 + (zoneoffset % 100);
864         if (timestamp[m[3].rm_so] == '-')
865                 zoneoffset = -zoneoffset;
866
867         /*
868          * YYYY-MM-DD hh:mm:ss must be from either 1969-12-31
869          * (west of GMT) or 1970-01-01 (east of GMT)
870          */
871         if ((zoneoffset < 0 && memcmp(timestamp, "1969-12-31", 10)) ||
872             (0 <= zoneoffset && memcmp(timestamp, "1970-01-01", 10)))
873                 return 0;
874
875         hourminute = (strtol(timestamp + 11, NULL, 10) * 60 +
876                       strtol(timestamp + 14, NULL, 10) -
877                       zoneoffset);
878
879         return ((zoneoffset < 0 && hourminute == 1440) ||
880                 (0 <= zoneoffset && !hourminute));
881 }
882
883 /*
884  * Get the name etc info from the ---/+++ lines of a traditional patch header
885  *
886  * FIXME! The end-of-filename heuristics are kind of screwy. For existing
887  * files, we can happily check the index for a match, but for creating a
888  * new file we should try to match whatever "patch" does. I have no idea.
889  */
890 static int parse_traditional_patch(struct apply_state *state,
891                                    const char *first,
892                                    const char *second,
893                                    struct patch *patch)
894 {
895         char *name;
896
897         first += 4;     /* skip "--- " */
898         second += 4;    /* skip "+++ " */
899         if (!state->p_value_known) {
900                 int p, q;
901                 p = guess_p_value(state, first);
902                 q = guess_p_value(state, second);
903                 if (p < 0) p = q;
904                 if (0 <= p && p == q) {
905                         state->p_value = p;
906                         state->p_value_known = 1;
907                 }
908         }
909         if (is_dev_null(first)) {
910                 patch->is_new = 1;
911                 patch->is_delete = 0;
912                 name = find_name_traditional(state, second, NULL, state->p_value);
913                 patch->new_name = name;
914         } else if (is_dev_null(second)) {
915                 patch->is_new = 0;
916                 patch->is_delete = 1;
917                 name = find_name_traditional(state, first, NULL, state->p_value);
918                 patch->old_name = name;
919         } else {
920                 char *first_name;
921                 first_name = find_name_traditional(state, first, NULL, state->p_value);
922                 name = find_name_traditional(state, second, first_name, state->p_value);
923                 free(first_name);
924                 if (has_epoch_timestamp(first)) {
925                         patch->is_new = 1;
926                         patch->is_delete = 0;
927                         patch->new_name = name;
928                 } else if (has_epoch_timestamp(second)) {
929                         patch->is_new = 0;
930                         patch->is_delete = 1;
931                         patch->old_name = name;
932                 } else {
933                         patch->old_name = name;
934                         patch->new_name = xstrdup_or_null(name);
935                 }
936         }
937         if (!name)
938                 return error(_("unable to find filename in patch at line %d"), state->linenr);
939
940         return 0;
941 }
942
943 static int gitdiff_hdrend(struct apply_state *state,
944                           const char *line,
945                           struct patch *patch)
946 {
947         return 1;
948 }
949
950 /*
951  * We're anal about diff header consistency, to make
952  * sure that we don't end up having strange ambiguous
953  * patches floating around.
954  *
955  * As a result, gitdiff_{old|new}name() will check
956  * their names against any previous information, just
957  * to make sure..
958  */
959 #define DIFF_OLD_NAME 0
960 #define DIFF_NEW_NAME 1
961
962 static int gitdiff_verify_name(struct apply_state *state,
963                                const char *line,
964                                int isnull,
965                                char **name,
966                                int side)
967 {
968         if (!*name && !isnull) {
969                 *name = find_name(state, line, NULL, state->p_value, TERM_TAB);
970                 return 0;
971         }
972
973         if (*name) {
974                 int len = strlen(*name);
975                 char *another;
976                 if (isnull)
977                         return error(_("git apply: bad git-diff - expected /dev/null, got %s on line %d"),
978                                      *name, state->linenr);
979                 another = find_name(state, line, NULL, state->p_value, TERM_TAB);
980                 if (!another || memcmp(another, *name, len + 1)) {
981                         free(another);
982                         return error((side == DIFF_NEW_NAME) ?
983                             _("git apply: bad git-diff - inconsistent new filename on line %d") :
984                             _("git apply: bad git-diff - inconsistent old filename on line %d"), state->linenr);
985                 }
986                 free(another);
987         } else {
988                 /* expect "/dev/null" */
989                 if (memcmp("/dev/null", line, 9) || line[9] != '\n')
990                         return error(_("git apply: bad git-diff - expected /dev/null on line %d"), state->linenr);
991         }
992
993         return 0;
994 }
995
996 static int gitdiff_oldname(struct apply_state *state,
997                            const char *line,
998                            struct patch *patch)
999 {
1000         return gitdiff_verify_name(state, line,
1001                                    patch->is_new, &patch->old_name,
1002                                    DIFF_OLD_NAME);
1003 }
1004
1005 static int gitdiff_newname(struct apply_state *state,
1006                            const char *line,
1007                            struct patch *patch)
1008 {
1009         return gitdiff_verify_name(state, line,
1010                                    patch->is_delete, &patch->new_name,
1011                                    DIFF_NEW_NAME);
1012 }
1013
1014 static int gitdiff_oldmode(struct apply_state *state,
1015                            const char *line,
1016                            struct patch *patch)
1017 {
1018         patch->old_mode = strtoul(line, NULL, 8);
1019         return 0;
1020 }
1021
1022 static int gitdiff_newmode(struct apply_state *state,
1023                            const char *line,
1024                            struct patch *patch)
1025 {
1026         patch->new_mode = strtoul(line, NULL, 8);
1027         return 0;
1028 }
1029
1030 static int gitdiff_delete(struct apply_state *state,
1031                           const char *line,
1032                           struct patch *patch)
1033 {
1034         patch->is_delete = 1;
1035         free(patch->old_name);
1036         patch->old_name = xstrdup_or_null(patch->def_name);
1037         return gitdiff_oldmode(state, line, patch);
1038 }
1039
1040 static int gitdiff_newfile(struct apply_state *state,
1041                            const char *line,
1042                            struct patch *patch)
1043 {
1044         patch->is_new = 1;
1045         free(patch->new_name);
1046         patch->new_name = xstrdup_or_null(patch->def_name);
1047         return gitdiff_newmode(state, line, patch);
1048 }
1049
1050 static int gitdiff_copysrc(struct apply_state *state,
1051                            const char *line,
1052                            struct patch *patch)
1053 {
1054         patch->is_copy = 1;
1055         free(patch->old_name);
1056         patch->old_name = find_name(state, line, NULL, state->p_value ? state->p_value - 1 : 0, 0);
1057         return 0;
1058 }
1059
1060 static int gitdiff_copydst(struct apply_state *state,
1061                            const char *line,
1062                            struct patch *patch)
1063 {
1064         patch->is_copy = 1;
1065         free(patch->new_name);
1066         patch->new_name = find_name(state, line, NULL, state->p_value ? state->p_value - 1 : 0, 0);
1067         return 0;
1068 }
1069
1070 static int gitdiff_renamesrc(struct apply_state *state,
1071                              const char *line,
1072                              struct patch *patch)
1073 {
1074         patch->is_rename = 1;
1075         free(patch->old_name);
1076         patch->old_name = find_name(state, line, NULL, state->p_value ? state->p_value - 1 : 0, 0);
1077         return 0;
1078 }
1079
1080 static int gitdiff_renamedst(struct apply_state *state,
1081                              const char *line,
1082                              struct patch *patch)
1083 {
1084         patch->is_rename = 1;
1085         free(patch->new_name);
1086         patch->new_name = find_name(state, line, NULL, state->p_value ? state->p_value - 1 : 0, 0);
1087         return 0;
1088 }
1089
1090 static int gitdiff_similarity(struct apply_state *state,
1091                               const char *line,
1092                               struct patch *patch)
1093 {
1094         unsigned long val = strtoul(line, NULL, 10);
1095         if (val <= 100)
1096                 patch->score = val;
1097         return 0;
1098 }
1099
1100 static int gitdiff_dissimilarity(struct apply_state *state,
1101                                  const char *line,
1102                                  struct patch *patch)
1103 {
1104         unsigned long val = strtoul(line, NULL, 10);
1105         if (val <= 100)
1106                 patch->score = val;
1107         return 0;
1108 }
1109
1110 static int gitdiff_index(struct apply_state *state,
1111                          const char *line,
1112                          struct patch *patch)
1113 {
1114         /*
1115          * index line is N hexadecimal, "..", N hexadecimal,
1116          * and optional space with octal mode.
1117          */
1118         const char *ptr, *eol;
1119         int len;
1120
1121         ptr = strchr(line, '.');
1122         if (!ptr || ptr[1] != '.' || 40 < ptr - line)
1123                 return 0;
1124         len = ptr - line;
1125         memcpy(patch->old_sha1_prefix, line, len);
1126         patch->old_sha1_prefix[len] = 0;
1127
1128         line = ptr + 2;
1129         ptr = strchr(line, ' ');
1130         eol = strchrnul(line, '\n');
1131
1132         if (!ptr || eol < ptr)
1133                 ptr = eol;
1134         len = ptr - line;
1135
1136         if (40 < len)
1137                 return 0;
1138         memcpy(patch->new_sha1_prefix, line, len);
1139         patch->new_sha1_prefix[len] = 0;
1140         if (*ptr == ' ')
1141                 patch->old_mode = strtoul(ptr+1, NULL, 8);
1142         return 0;
1143 }
1144
1145 /*
1146  * This is normal for a diff that doesn't change anything: we'll fall through
1147  * into the next diff. Tell the parser to break out.
1148  */
1149 static int gitdiff_unrecognized(struct apply_state *state,
1150                                 const char *line,
1151                                 struct patch *patch)
1152 {
1153         return 1;
1154 }
1155
1156 /*
1157  * Skip p_value leading components from "line"; as we do not accept
1158  * absolute paths, return NULL in that case.
1159  */
1160 static const char *skip_tree_prefix(struct apply_state *state,
1161                                     const char *line,
1162                                     int llen)
1163 {
1164         int nslash;
1165         int i;
1166
1167         if (!state->p_value)
1168                 return (llen && line[0] == '/') ? NULL : line;
1169
1170         nslash = state->p_value;
1171         for (i = 0; i < llen; i++) {
1172                 int ch = line[i];
1173                 if (ch == '/' && --nslash <= 0)
1174                         return (i == 0) ? NULL : &line[i + 1];
1175         }
1176         return NULL;
1177 }
1178
1179 /*
1180  * This is to extract the same name that appears on "diff --git"
1181  * line.  We do not find and return anything if it is a rename
1182  * patch, and it is OK because we will find the name elsewhere.
1183  * We need to reliably find name only when it is mode-change only,
1184  * creation or deletion of an empty file.  In any of these cases,
1185  * both sides are the same name under a/ and b/ respectively.
1186  */
1187 static char *git_header_name(struct apply_state *state,
1188                              const char *line,
1189                              int llen)
1190 {
1191         const char *name;
1192         const char *second = NULL;
1193         size_t len, line_len;
1194
1195         line += strlen("diff --git ");
1196         llen -= strlen("diff --git ");
1197
1198         if (*line == '"') {
1199                 const char *cp;
1200                 struct strbuf first = STRBUF_INIT;
1201                 struct strbuf sp = STRBUF_INIT;
1202
1203                 if (unquote_c_style(&first, line, &second))
1204                         goto free_and_fail1;
1205
1206                 /* strip the a/b prefix including trailing slash */
1207                 cp = skip_tree_prefix(state, first.buf, first.len);
1208                 if (!cp)
1209                         goto free_and_fail1;
1210                 strbuf_remove(&first, 0, cp - first.buf);
1211
1212                 /*
1213                  * second points at one past closing dq of name.
1214                  * find the second name.
1215                  */
1216                 while ((second < line + llen) && isspace(*second))
1217                         second++;
1218
1219                 if (line + llen <= second)
1220                         goto free_and_fail1;
1221                 if (*second == '"') {
1222                         if (unquote_c_style(&sp, second, NULL))
1223                                 goto free_and_fail1;
1224                         cp = skip_tree_prefix(state, sp.buf, sp.len);
1225                         if (!cp)
1226                                 goto free_and_fail1;
1227                         /* They must match, otherwise ignore */
1228                         if (strcmp(cp, first.buf))
1229                                 goto free_and_fail1;
1230                         strbuf_release(&sp);
1231                         return strbuf_detach(&first, NULL);
1232                 }
1233
1234                 /* unquoted second */
1235                 cp = skip_tree_prefix(state, second, line + llen - second);
1236                 if (!cp)
1237                         goto free_and_fail1;
1238                 if (line + llen - cp != first.len ||
1239                     memcmp(first.buf, cp, first.len))
1240                         goto free_and_fail1;
1241                 return strbuf_detach(&first, NULL);
1242
1243         free_and_fail1:
1244                 strbuf_release(&first);
1245                 strbuf_release(&sp);
1246                 return NULL;
1247         }
1248
1249         /* unquoted first name */
1250         name = skip_tree_prefix(state, line, llen);
1251         if (!name)
1252                 return NULL;
1253
1254         /*
1255          * since the first name is unquoted, a dq if exists must be
1256          * the beginning of the second name.
1257          */
1258         for (second = name; second < line + llen; second++) {
1259                 if (*second == '"') {
1260                         struct strbuf sp = STRBUF_INIT;
1261                         const char *np;
1262
1263                         if (unquote_c_style(&sp, second, NULL))
1264                                 goto free_and_fail2;
1265
1266                         np = skip_tree_prefix(state, sp.buf, sp.len);
1267                         if (!np)
1268                                 goto free_and_fail2;
1269
1270                         len = sp.buf + sp.len - np;
1271                         if (len < second - name &&
1272                             !strncmp(np, name, len) &&
1273                             isspace(name[len])) {
1274                                 /* Good */
1275                                 strbuf_remove(&sp, 0, np - sp.buf);
1276                                 return strbuf_detach(&sp, NULL);
1277                         }
1278
1279                 free_and_fail2:
1280                         strbuf_release(&sp);
1281                         return NULL;
1282                 }
1283         }
1284
1285         /*
1286          * Accept a name only if it shows up twice, exactly the same
1287          * form.
1288          */
1289         second = strchr(name, '\n');
1290         if (!second)
1291                 return NULL;
1292         line_len = second - name;
1293         for (len = 0 ; ; len++) {
1294                 switch (name[len]) {
1295                 default:
1296                         continue;
1297                 case '\n':
1298                         return NULL;
1299                 case '\t': case ' ':
1300                         /*
1301                          * Is this the separator between the preimage
1302                          * and the postimage pathname?  Again, we are
1303                          * only interested in the case where there is
1304                          * no rename, as this is only to set def_name
1305                          * and a rename patch has the names elsewhere
1306                          * in an unambiguous form.
1307                          */
1308                         if (!name[len + 1])
1309                                 return NULL; /* no postimage name */
1310                         second = skip_tree_prefix(state, name + len + 1,
1311                                                   line_len - (len + 1));
1312                         if (!second)
1313                                 return NULL;
1314                         /*
1315                          * Does len bytes starting at "name" and "second"
1316                          * (that are separated by one HT or SP we just
1317                          * found) exactly match?
1318                          */
1319                         if (second[len] == '\n' && !strncmp(name, second, len))
1320                                 return xmemdupz(name, len);
1321                 }
1322         }
1323 }
1324
1325 /* Verify that we recognize the lines following a git header */
1326 static int parse_git_header(struct apply_state *state,
1327                             const char *line,
1328                             int len,
1329                             unsigned int size,
1330                             struct patch *patch)
1331 {
1332         unsigned long offset;
1333
1334         /* A git diff has explicit new/delete information, so we don't guess */
1335         patch->is_new = 0;
1336         patch->is_delete = 0;
1337
1338         /*
1339          * Some things may not have the old name in the
1340          * rest of the headers anywhere (pure mode changes,
1341          * or removing or adding empty files), so we get
1342          * the default name from the header.
1343          */
1344         patch->def_name = git_header_name(state, line, len);
1345         if (patch->def_name && state->root.len) {
1346                 char *s = xstrfmt("%s%s", state->root.buf, patch->def_name);
1347                 free(patch->def_name);
1348                 patch->def_name = s;
1349         }
1350
1351         line += len;
1352         size -= len;
1353         state->linenr++;
1354         for (offset = len ; size > 0 ; offset += len, size -= len, line += len, state->linenr++) {
1355                 static const struct opentry {
1356                         const char *str;
1357                         int (*fn)(struct apply_state *, const char *, struct patch *);
1358                 } optable[] = {
1359                         { "@@ -", gitdiff_hdrend },
1360                         { "--- ", gitdiff_oldname },
1361                         { "+++ ", gitdiff_newname },
1362                         { "old mode ", gitdiff_oldmode },
1363                         { "new mode ", gitdiff_newmode },
1364                         { "deleted file mode ", gitdiff_delete },
1365                         { "new file mode ", gitdiff_newfile },
1366                         { "copy from ", gitdiff_copysrc },
1367                         { "copy to ", gitdiff_copydst },
1368                         { "rename old ", gitdiff_renamesrc },
1369                         { "rename new ", gitdiff_renamedst },
1370                         { "rename from ", gitdiff_renamesrc },
1371                         { "rename to ", gitdiff_renamedst },
1372                         { "similarity index ", gitdiff_similarity },
1373                         { "dissimilarity index ", gitdiff_dissimilarity },
1374                         { "index ", gitdiff_index },
1375                         { "", gitdiff_unrecognized },
1376                 };
1377                 int i;
1378
1379                 len = linelen(line, size);
1380                 if (!len || line[len-1] != '\n')
1381                         break;
1382                 for (i = 0; i < ARRAY_SIZE(optable); i++) {
1383                         const struct opentry *p = optable + i;
1384                         int oplen = strlen(p->str);
1385                         int res;
1386                         if (len < oplen || memcmp(p->str, line, oplen))
1387                                 continue;
1388                         res = p->fn(state, line + oplen, patch);
1389                         if (res < 0)
1390                                 return -1;
1391                         if (res > 0)
1392                                 return offset;
1393                         break;
1394                 }
1395         }
1396
1397         return offset;
1398 }
1399
1400 static int parse_num(const char *line, unsigned long *p)
1401 {
1402         char *ptr;
1403
1404         if (!isdigit(*line))
1405                 return 0;
1406         *p = strtoul(line, &ptr, 10);
1407         return ptr - line;
1408 }
1409
1410 static int parse_range(const char *line, int len, int offset, const char *expect,
1411                        unsigned long *p1, unsigned long *p2)
1412 {
1413         int digits, ex;
1414
1415         if (offset < 0 || offset >= len)
1416                 return -1;
1417         line += offset;
1418         len -= offset;
1419
1420         digits = parse_num(line, p1);
1421         if (!digits)
1422                 return -1;
1423
1424         offset += digits;
1425         line += digits;
1426         len -= digits;
1427
1428         *p2 = 1;
1429         if (*line == ',') {
1430                 digits = parse_num(line+1, p2);
1431                 if (!digits)
1432                         return -1;
1433
1434                 offset += digits+1;
1435                 line += digits+1;
1436                 len -= digits+1;
1437         }
1438
1439         ex = strlen(expect);
1440         if (ex > len)
1441                 return -1;
1442         if (memcmp(line, expect, ex))
1443                 return -1;
1444
1445         return offset + ex;
1446 }
1447
1448 static void recount_diff(const char *line, int size, struct fragment *fragment)
1449 {
1450         int oldlines = 0, newlines = 0, ret = 0;
1451
1452         if (size < 1) {
1453                 warning("recount: ignore empty hunk");
1454                 return;
1455         }
1456
1457         for (;;) {
1458                 int len = linelen(line, size);
1459                 size -= len;
1460                 line += len;
1461
1462                 if (size < 1)
1463                         break;
1464
1465                 switch (*line) {
1466                 case ' ': case '\n':
1467                         newlines++;
1468                         /* fall through */
1469                 case '-':
1470                         oldlines++;
1471                         continue;
1472                 case '+':
1473                         newlines++;
1474                         continue;
1475                 case '\\':
1476                         continue;
1477                 case '@':
1478                         ret = size < 3 || !starts_with(line, "@@ ");
1479                         break;
1480                 case 'd':
1481                         ret = size < 5 || !starts_with(line, "diff ");
1482                         break;
1483                 default:
1484                         ret = -1;
1485                         break;
1486                 }
1487                 if (ret) {
1488                         warning(_("recount: unexpected line: %.*s"),
1489                                 (int)linelen(line, size), line);
1490                         return;
1491                 }
1492                 break;
1493         }
1494         fragment->oldlines = oldlines;
1495         fragment->newlines = newlines;
1496 }
1497
1498 /*
1499  * Parse a unified diff fragment header of the
1500  * form "@@ -a,b +c,d @@"
1501  */
1502 static int parse_fragment_header(const char *line, int len, struct fragment *fragment)
1503 {
1504         int offset;
1505
1506         if (!len || line[len-1] != '\n')
1507                 return -1;
1508
1509         /* Figure out the number of lines in a fragment */
1510         offset = parse_range(line, len, 4, " +", &fragment->oldpos, &fragment->oldlines);
1511         offset = parse_range(line, len, offset, " @@", &fragment->newpos, &fragment->newlines);
1512
1513         return offset;
1514 }
1515
1516 /*
1517  * Find file diff header
1518  *
1519  * Returns:
1520  *  -1 if no header was found
1521  *  -128 in case of error
1522  *   the size of the header in bytes (called "offset") otherwise
1523  */
1524 static int find_header(struct apply_state *state,
1525                        const char *line,
1526                        unsigned long size,
1527                        int *hdrsize,
1528                        struct patch *patch)
1529 {
1530         unsigned long offset, len;
1531
1532         patch->is_toplevel_relative = 0;
1533         patch->is_rename = patch->is_copy = 0;
1534         patch->is_new = patch->is_delete = -1;
1535         patch->old_mode = patch->new_mode = 0;
1536         patch->old_name = patch->new_name = NULL;
1537         for (offset = 0; size > 0; offset += len, size -= len, line += len, state->linenr++) {
1538                 unsigned long nextlen;
1539
1540                 len = linelen(line, size);
1541                 if (!len)
1542                         break;
1543
1544                 /* Testing this early allows us to take a few shortcuts.. */
1545                 if (len < 6)
1546                         continue;
1547
1548                 /*
1549                  * Make sure we don't find any unconnected patch fragments.
1550                  * That's a sign that we didn't find a header, and that a
1551                  * patch has become corrupted/broken up.
1552                  */
1553                 if (!memcmp("@@ -", line, 4)) {
1554                         struct fragment dummy;
1555                         if (parse_fragment_header(line, len, &dummy) < 0)
1556                                 continue;
1557                         error(_("patch fragment without header at line %d: %.*s"),
1558                                      state->linenr, (int)len-1, line);
1559                         return -128;
1560                 }
1561
1562                 if (size < len + 6)
1563                         break;
1564
1565                 /*
1566                  * Git patch? It might not have a real patch, just a rename
1567                  * or mode change, so we handle that specially
1568                  */
1569                 if (!memcmp("diff --git ", line, 11)) {
1570                         int git_hdr_len = parse_git_header(state, line, len, size, patch);
1571                         if (git_hdr_len < 0)
1572                                 return -128;
1573                         if (git_hdr_len <= len)
1574                                 continue;
1575                         if (!patch->old_name && !patch->new_name) {
1576                                 if (!patch->def_name) {
1577                                         error(Q_("git diff header lacks filename information when removing "
1578                                                         "%d leading pathname component (line %d)",
1579                                                         "git diff header lacks filename information when removing "
1580                                                         "%d leading pathname components (line %d)",
1581                                                         state->p_value),
1582                                                      state->p_value, state->linenr);
1583                                         return -128;
1584                                 }
1585                                 patch->old_name = xstrdup(patch->def_name);
1586                                 patch->new_name = xstrdup(patch->def_name);
1587                         }
1588                         if (!patch->is_delete && !patch->new_name) {
1589                                 error(_("git diff header lacks filename information "
1590                                              "(line %d)"), state->linenr);
1591                                 return -128;
1592                         }
1593                         patch->is_toplevel_relative = 1;
1594                         *hdrsize = git_hdr_len;
1595                         return offset;
1596                 }
1597
1598                 /* --- followed by +++ ? */
1599                 if (memcmp("--- ", line,  4) || memcmp("+++ ", line + len, 4))
1600                         continue;
1601
1602                 /*
1603                  * We only accept unified patches, so we want it to
1604                  * at least have "@@ -a,b +c,d @@\n", which is 14 chars
1605                  * minimum ("@@ -0,0 +1 @@\n" is the shortest).
1606                  */
1607                 nextlen = linelen(line + len, size - len);
1608                 if (size < nextlen + 14 || memcmp("@@ -", line + len + nextlen, 4))
1609                         continue;
1610
1611                 /* Ok, we'll consider it a patch */
1612                 if (parse_traditional_patch(state, line, line+len, patch))
1613                         return -128;
1614                 *hdrsize = len + nextlen;
1615                 state->linenr += 2;
1616                 return offset;
1617         }
1618         return -1;
1619 }
1620
1621 static void record_ws_error(struct apply_state *state,
1622                             unsigned result,
1623                             const char *line,
1624                             int len,
1625                             int linenr)
1626 {
1627         char *err;
1628
1629         if (!result)
1630                 return;
1631
1632         state->whitespace_error++;
1633         if (state->squelch_whitespace_errors &&
1634             state->squelch_whitespace_errors < state->whitespace_error)
1635                 return;
1636
1637         err = whitespace_error_string(result);
1638         if (state->apply_verbosity > verbosity_silent)
1639                 fprintf(stderr, "%s:%d: %s.\n%.*s\n",
1640                         state->patch_input_file, linenr, err, len, line);
1641         free(err);
1642 }
1643
1644 static void check_whitespace(struct apply_state *state,
1645                              const char *line,
1646                              int len,
1647                              unsigned ws_rule)
1648 {
1649         unsigned result = ws_check(line + 1, len - 1, ws_rule);
1650
1651         record_ws_error(state, result, line + 1, len - 2, state->linenr);
1652 }
1653
1654 /*
1655  * Parse a unified diff. Note that this really needs to parse each
1656  * fragment separately, since the only way to know the difference
1657  * between a "---" that is part of a patch, and a "---" that starts
1658  * the next patch is to look at the line counts..
1659  */
1660 static int parse_fragment(struct apply_state *state,
1661                           const char *line,
1662                           unsigned long size,
1663                           struct patch *patch,
1664                           struct fragment *fragment)
1665 {
1666         int added, deleted;
1667         int len = linelen(line, size), offset;
1668         unsigned long oldlines, newlines;
1669         unsigned long leading, trailing;
1670
1671         offset = parse_fragment_header(line, len, fragment);
1672         if (offset < 0)
1673                 return -1;
1674         if (offset > 0 && patch->recount)
1675                 recount_diff(line + offset, size - offset, fragment);
1676         oldlines = fragment->oldlines;
1677         newlines = fragment->newlines;
1678         leading = 0;
1679         trailing = 0;
1680
1681         /* Parse the thing.. */
1682         line += len;
1683         size -= len;
1684         state->linenr++;
1685         added = deleted = 0;
1686         for (offset = len;
1687              0 < size;
1688              offset += len, size -= len, line += len, state->linenr++) {
1689                 if (!oldlines && !newlines)
1690                         break;
1691                 len = linelen(line, size);
1692                 if (!len || line[len-1] != '\n')
1693                         return -1;
1694                 switch (*line) {
1695                 default:
1696                         return -1;
1697                 case '\n': /* newer GNU diff, an empty context line */
1698                 case ' ':
1699                         oldlines--;
1700                         newlines--;
1701                         if (!deleted && !added)
1702                                 leading++;
1703                         trailing++;
1704                         if (!state->apply_in_reverse &&
1705                             state->ws_error_action == correct_ws_error)
1706                                 check_whitespace(state, line, len, patch->ws_rule);
1707                         break;
1708                 case '-':
1709                         if (state->apply_in_reverse &&
1710                             state->ws_error_action != nowarn_ws_error)
1711                                 check_whitespace(state, line, len, patch->ws_rule);
1712                         deleted++;
1713                         oldlines--;
1714                         trailing = 0;
1715                         break;
1716                 case '+':
1717                         if (!state->apply_in_reverse &&
1718                             state->ws_error_action != nowarn_ws_error)
1719                                 check_whitespace(state, line, len, patch->ws_rule);
1720                         added++;
1721                         newlines--;
1722                         trailing = 0;
1723                         break;
1724
1725                 /*
1726                  * We allow "\ No newline at end of file". Depending
1727                  * on locale settings when the patch was produced we
1728                  * don't know what this line looks like. The only
1729                  * thing we do know is that it begins with "\ ".
1730                  * Checking for 12 is just for sanity check -- any
1731                  * l10n of "\ No newline..." is at least that long.
1732                  */
1733                 case '\\':
1734                         if (len < 12 || memcmp(line, "\\ ", 2))
1735                                 return -1;
1736                         break;
1737                 }
1738         }
1739         if (oldlines || newlines)
1740                 return -1;
1741         if (!deleted && !added)
1742                 return -1;
1743
1744         fragment->leading = leading;
1745         fragment->trailing = trailing;
1746
1747         /*
1748          * If a fragment ends with an incomplete line, we failed to include
1749          * it in the above loop because we hit oldlines == newlines == 0
1750          * before seeing it.
1751          */
1752         if (12 < size && !memcmp(line, "\\ ", 2))
1753                 offset += linelen(line, size);
1754
1755         patch->lines_added += added;
1756         patch->lines_deleted += deleted;
1757
1758         if (0 < patch->is_new && oldlines)
1759                 return error(_("new file depends on old contents"));
1760         if (0 < patch->is_delete && newlines)
1761                 return error(_("deleted file still has contents"));
1762         return offset;
1763 }
1764
1765 /*
1766  * We have seen "diff --git a/... b/..." header (or a traditional patch
1767  * header).  Read hunks that belong to this patch into fragments and hang
1768  * them to the given patch structure.
1769  *
1770  * The (fragment->patch, fragment->size) pair points into the memory given
1771  * by the caller, not a copy, when we return.
1772  *
1773  * Returns:
1774  *   -1 in case of error,
1775  *   the number of bytes in the patch otherwise.
1776  */
1777 static int parse_single_patch(struct apply_state *state,
1778                               const char *line,
1779                               unsigned long size,
1780                               struct patch *patch)
1781 {
1782         unsigned long offset = 0;
1783         unsigned long oldlines = 0, newlines = 0, context = 0;
1784         struct fragment **fragp = &patch->fragments;
1785
1786         while (size > 4 && !memcmp(line, "@@ -", 4)) {
1787                 struct fragment *fragment;
1788                 int len;
1789
1790                 fragment = xcalloc(1, sizeof(*fragment));
1791                 fragment->linenr = state->linenr;
1792                 len = parse_fragment(state, line, size, patch, fragment);
1793                 if (len <= 0) {
1794                         free(fragment);
1795                         return error(_("corrupt patch at line %d"), state->linenr);
1796                 }
1797                 fragment->patch = line;
1798                 fragment->size = len;
1799                 oldlines += fragment->oldlines;
1800                 newlines += fragment->newlines;
1801                 context += fragment->leading + fragment->trailing;
1802
1803                 *fragp = fragment;
1804                 fragp = &fragment->next;
1805
1806                 offset += len;
1807                 line += len;
1808                 size -= len;
1809         }
1810
1811         /*
1812          * If something was removed (i.e. we have old-lines) it cannot
1813          * be creation, and if something was added it cannot be
1814          * deletion.  However, the reverse is not true; --unified=0
1815          * patches that only add are not necessarily creation even
1816          * though they do not have any old lines, and ones that only
1817          * delete are not necessarily deletion.
1818          *
1819          * Unfortunately, a real creation/deletion patch do _not_ have
1820          * any context line by definition, so we cannot safely tell it
1821          * apart with --unified=0 insanity.  At least if the patch has
1822          * more than one hunk it is not creation or deletion.
1823          */
1824         if (patch->is_new < 0 &&
1825             (oldlines || (patch->fragments && patch->fragments->next)))
1826                 patch->is_new = 0;
1827         if (patch->is_delete < 0 &&
1828             (newlines || (patch->fragments && patch->fragments->next)))
1829                 patch->is_delete = 0;
1830
1831         if (0 < patch->is_new && oldlines)
1832                 return error(_("new file %s depends on old contents"), patch->new_name);
1833         if (0 < patch->is_delete && newlines)
1834                 return error(_("deleted file %s still has contents"), patch->old_name);
1835         if (!patch->is_delete && !newlines && context && state->apply_verbosity > verbosity_silent)
1836                 fprintf_ln(stderr,
1837                            _("** warning: "
1838                              "file %s becomes empty but is not deleted"),
1839                            patch->new_name);
1840
1841         return offset;
1842 }
1843
1844 static inline int metadata_changes(struct patch *patch)
1845 {
1846         return  patch->is_rename > 0 ||
1847                 patch->is_copy > 0 ||
1848                 patch->is_new > 0 ||
1849                 patch->is_delete ||
1850                 (patch->old_mode && patch->new_mode &&
1851                  patch->old_mode != patch->new_mode);
1852 }
1853
1854 static char *inflate_it(const void *data, unsigned long size,
1855                         unsigned long inflated_size)
1856 {
1857         git_zstream stream;
1858         void *out;
1859         int st;
1860
1861         memset(&stream, 0, sizeof(stream));
1862
1863         stream.next_in = (unsigned char *)data;
1864         stream.avail_in = size;
1865         stream.next_out = out = xmalloc(inflated_size);
1866         stream.avail_out = inflated_size;
1867         git_inflate_init(&stream);
1868         st = git_inflate(&stream, Z_FINISH);
1869         git_inflate_end(&stream);
1870         if ((st != Z_STREAM_END) || stream.total_out != inflated_size) {
1871                 free(out);
1872                 return NULL;
1873         }
1874         return out;
1875 }
1876
1877 /*
1878  * Read a binary hunk and return a new fragment; fragment->patch
1879  * points at an allocated memory that the caller must free, so
1880  * it is marked as "->free_patch = 1".
1881  */
1882 static struct fragment *parse_binary_hunk(struct apply_state *state,
1883                                           char **buf_p,
1884                                           unsigned long *sz_p,
1885                                           int *status_p,
1886                                           int *used_p)
1887 {
1888         /*
1889          * Expect a line that begins with binary patch method ("literal"
1890          * or "delta"), followed by the length of data before deflating.
1891          * a sequence of 'length-byte' followed by base-85 encoded data
1892          * should follow, terminated by a newline.
1893          *
1894          * Each 5-byte sequence of base-85 encodes up to 4 bytes,
1895          * and we would limit the patch line to 66 characters,
1896          * so one line can fit up to 13 groups that would decode
1897          * to 52 bytes max.  The length byte 'A'-'Z' corresponds
1898          * to 1-26 bytes, and 'a'-'z' corresponds to 27-52 bytes.
1899          */
1900         int llen, used;
1901         unsigned long size = *sz_p;
1902         char *buffer = *buf_p;
1903         int patch_method;
1904         unsigned long origlen;
1905         char *data = NULL;
1906         int hunk_size = 0;
1907         struct fragment *frag;
1908
1909         llen = linelen(buffer, size);
1910         used = llen;
1911
1912         *status_p = 0;
1913
1914         if (starts_with(buffer, "delta ")) {
1915                 patch_method = BINARY_DELTA_DEFLATED;
1916                 origlen = strtoul(buffer + 6, NULL, 10);
1917         }
1918         else if (starts_with(buffer, "literal ")) {
1919                 patch_method = BINARY_LITERAL_DEFLATED;
1920                 origlen = strtoul(buffer + 8, NULL, 10);
1921         }
1922         else
1923                 return NULL;
1924
1925         state->linenr++;
1926         buffer += llen;
1927         while (1) {
1928                 int byte_length, max_byte_length, newsize;
1929                 llen = linelen(buffer, size);
1930                 used += llen;
1931                 state->linenr++;
1932                 if (llen == 1) {
1933                         /* consume the blank line */
1934                         buffer++;
1935                         size--;
1936                         break;
1937                 }
1938                 /*
1939                  * Minimum line is "A00000\n" which is 7-byte long,
1940                  * and the line length must be multiple of 5 plus 2.
1941                  */
1942                 if ((llen < 7) || (llen-2) % 5)
1943                         goto corrupt;
1944                 max_byte_length = (llen - 2) / 5 * 4;
1945                 byte_length = *buffer;
1946                 if ('A' <= byte_length && byte_length <= 'Z')
1947                         byte_length = byte_length - 'A' + 1;
1948                 else if ('a' <= byte_length && byte_length <= 'z')
1949                         byte_length = byte_length - 'a' + 27;
1950                 else
1951                         goto corrupt;
1952                 /* if the input length was not multiple of 4, we would
1953                  * have filler at the end but the filler should never
1954                  * exceed 3 bytes
1955                  */
1956                 if (max_byte_length < byte_length ||
1957                     byte_length <= max_byte_length - 4)
1958                         goto corrupt;
1959                 newsize = hunk_size + byte_length;
1960                 data = xrealloc(data, newsize);
1961                 if (decode_85(data + hunk_size, buffer + 1, byte_length))
1962                         goto corrupt;
1963                 hunk_size = newsize;
1964                 buffer += llen;
1965                 size -= llen;
1966         }
1967
1968         frag = xcalloc(1, sizeof(*frag));
1969         frag->patch = inflate_it(data, hunk_size, origlen);
1970         frag->free_patch = 1;
1971         if (!frag->patch)
1972                 goto corrupt;
1973         free(data);
1974         frag->size = origlen;
1975         *buf_p = buffer;
1976         *sz_p = size;
1977         *used_p = used;
1978         frag->binary_patch_method = patch_method;
1979         return frag;
1980
1981  corrupt:
1982         free(data);
1983         *status_p = -1;
1984         error(_("corrupt binary patch at line %d: %.*s"),
1985               state->linenr-1, llen-1, buffer);
1986         return NULL;
1987 }
1988
1989 /*
1990  * Returns:
1991  *   -1 in case of error,
1992  *   the length of the parsed binary patch otherwise
1993  */
1994 static int parse_binary(struct apply_state *state,
1995                         char *buffer,
1996                         unsigned long size,
1997                         struct patch *patch)
1998 {
1999         /*
2000          * We have read "GIT binary patch\n"; what follows is a line
2001          * that says the patch method (currently, either "literal" or
2002          * "delta") and the length of data before deflating; a
2003          * sequence of 'length-byte' followed by base-85 encoded data
2004          * follows.
2005          *
2006          * When a binary patch is reversible, there is another binary
2007          * hunk in the same format, starting with patch method (either
2008          * "literal" or "delta") with the length of data, and a sequence
2009          * of length-byte + base-85 encoded data, terminated with another
2010          * empty line.  This data, when applied to the postimage, produces
2011          * the preimage.
2012          */
2013         struct fragment *forward;
2014         struct fragment *reverse;
2015         int status;
2016         int used, used_1;
2017
2018         forward = parse_binary_hunk(state, &buffer, &size, &status, &used);
2019         if (!forward && !status)
2020                 /* there has to be one hunk (forward hunk) */
2021                 return error(_("unrecognized binary patch at line %d"), state->linenr-1);
2022         if (status)
2023                 /* otherwise we already gave an error message */
2024                 return status;
2025
2026         reverse = parse_binary_hunk(state, &buffer, &size, &status, &used_1);
2027         if (reverse)
2028                 used += used_1;
2029         else if (status) {
2030                 /*
2031                  * Not having reverse hunk is not an error, but having
2032                  * a corrupt reverse hunk is.
2033                  */
2034                 free((void*) forward->patch);
2035                 free(forward);
2036                 return status;
2037         }
2038         forward->next = reverse;
2039         patch->fragments = forward;
2040         patch->is_binary = 1;
2041         return used;
2042 }
2043
2044 static void prefix_one(struct apply_state *state, char **name)
2045 {
2046         char *old_name = *name;
2047         if (!old_name)
2048                 return;
2049         *name = xstrdup(prefix_filename(state->prefix, state->prefix_length, *name));
2050         free(old_name);
2051 }
2052
2053 static void prefix_patch(struct apply_state *state, struct patch *p)
2054 {
2055         if (!state->prefix || p->is_toplevel_relative)
2056                 return;
2057         prefix_one(state, &p->new_name);
2058         prefix_one(state, &p->old_name);
2059 }
2060
2061 /*
2062  * include/exclude
2063  */
2064
2065 static void add_name_limit(struct apply_state *state,
2066                            const char *name,
2067                            int exclude)
2068 {
2069         struct string_list_item *it;
2070
2071         it = string_list_append(&state->limit_by_name, name);
2072         it->util = exclude ? NULL : (void *) 1;
2073 }
2074
2075 static int use_patch(struct apply_state *state, struct patch *p)
2076 {
2077         const char *pathname = p->new_name ? p->new_name : p->old_name;
2078         int i;
2079
2080         /* Paths outside are not touched regardless of "--include" */
2081         if (0 < state->prefix_length) {
2082                 int pathlen = strlen(pathname);
2083                 if (pathlen <= state->prefix_length ||
2084                     memcmp(state->prefix, pathname, state->prefix_length))
2085                         return 0;
2086         }
2087
2088         /* See if it matches any of exclude/include rule */
2089         for (i = 0; i < state->limit_by_name.nr; i++) {
2090                 struct string_list_item *it = &state->limit_by_name.items[i];
2091                 if (!wildmatch(it->string, pathname, 0, NULL))
2092                         return (it->util != NULL);
2093         }
2094
2095         /*
2096          * If we had any include, a path that does not match any rule is
2097          * not used.  Otherwise, we saw bunch of exclude rules (or none)
2098          * and such a path is used.
2099          */
2100         return !state->has_include;
2101 }
2102
2103 /*
2104  * Read the patch text in "buffer" that extends for "size" bytes; stop
2105  * reading after seeing a single patch (i.e. changes to a single file).
2106  * Create fragments (i.e. patch hunks) and hang them to the given patch.
2107  *
2108  * Returns:
2109  *   -1 if no header was found or parse_binary() failed,
2110  *   -128 on another error,
2111  *   the number of bytes consumed otherwise,
2112  *     so that the caller can call us again for the next patch.
2113  */
2114 static int parse_chunk(struct apply_state *state, char *buffer, unsigned long size, struct patch *patch)
2115 {
2116         int hdrsize, patchsize;
2117         int offset = find_header(state, buffer, size, &hdrsize, patch);
2118
2119         if (offset < 0)
2120                 return offset;
2121
2122         prefix_patch(state, patch);
2123
2124         if (!use_patch(state, patch))
2125                 patch->ws_rule = 0;
2126         else
2127                 patch->ws_rule = whitespace_rule(patch->new_name
2128                                                  ? patch->new_name
2129                                                  : patch->old_name);
2130
2131         patchsize = parse_single_patch(state,
2132                                        buffer + offset + hdrsize,
2133                                        size - offset - hdrsize,
2134                                        patch);
2135
2136         if (patchsize < 0)
2137                 return -128;
2138
2139         if (!patchsize) {
2140                 static const char git_binary[] = "GIT binary patch\n";
2141                 int hd = hdrsize + offset;
2142                 unsigned long llen = linelen(buffer + hd, size - hd);
2143
2144                 if (llen == sizeof(git_binary) - 1 &&
2145                     !memcmp(git_binary, buffer + hd, llen)) {
2146                         int used;
2147                         state->linenr++;
2148                         used = parse_binary(state, buffer + hd + llen,
2149                                             size - hd - llen, patch);
2150                         if (used < 0)
2151                                 return -1;
2152                         if (used)
2153                                 patchsize = used + llen;
2154                         else
2155                                 patchsize = 0;
2156                 }
2157                 else if (!memcmp(" differ\n", buffer + hd + llen - 8, 8)) {
2158                         static const char *binhdr[] = {
2159                                 "Binary files ",
2160                                 "Files ",
2161                                 NULL,
2162                         };
2163                         int i;
2164                         for (i = 0; binhdr[i]; i++) {
2165                                 int len = strlen(binhdr[i]);
2166                                 if (len < size - hd &&
2167                                     !memcmp(binhdr[i], buffer + hd, len)) {
2168                                         state->linenr++;
2169                                         patch->is_binary = 1;
2170                                         patchsize = llen;
2171                                         break;
2172                                 }
2173                         }
2174                 }
2175
2176                 /* Empty patch cannot be applied if it is a text patch
2177                  * without metadata change.  A binary patch appears
2178                  * empty to us here.
2179                  */
2180                 if ((state->apply || state->check) &&
2181                     (!patch->is_binary && !metadata_changes(patch))) {
2182                         error(_("patch with only garbage at line %d"), state->linenr);
2183                         return -128;
2184                 }
2185         }
2186
2187         return offset + hdrsize + patchsize;
2188 }
2189
2190 #define swap(a,b) myswap((a),(b),sizeof(a))
2191
2192 #define myswap(a, b, size) do {         \
2193         unsigned char mytmp[size];      \
2194         memcpy(mytmp, &a, size);                \
2195         memcpy(&a, &b, size);           \
2196         memcpy(&b, mytmp, size);                \
2197 } while (0)
2198
2199 static void reverse_patches(struct patch *p)
2200 {
2201         for (; p; p = p->next) {
2202                 struct fragment *frag = p->fragments;
2203
2204                 swap(p->new_name, p->old_name);
2205                 swap(p->new_mode, p->old_mode);
2206                 swap(p->is_new, p->is_delete);
2207                 swap(p->lines_added, p->lines_deleted);
2208                 swap(p->old_sha1_prefix, p->new_sha1_prefix);
2209
2210                 for (; frag; frag = frag->next) {
2211                         swap(frag->newpos, frag->oldpos);
2212                         swap(frag->newlines, frag->oldlines);
2213                 }
2214         }
2215 }
2216
2217 static const char pluses[] =
2218 "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
2219 static const char minuses[]=
2220 "----------------------------------------------------------------------";
2221
2222 static void show_stats(struct apply_state *state, struct patch *patch)
2223 {
2224         struct strbuf qname = STRBUF_INIT;
2225         char *cp = patch->new_name ? patch->new_name : patch->old_name;
2226         int max, add, del;
2227
2228         quote_c_style(cp, &qname, NULL, 0);
2229
2230         /*
2231          * "scale" the filename
2232          */
2233         max = state->max_len;
2234         if (max > 50)
2235                 max = 50;
2236
2237         if (qname.len > max) {
2238                 cp = strchr(qname.buf + qname.len + 3 - max, '/');
2239                 if (!cp)
2240                         cp = qname.buf + qname.len + 3 - max;
2241                 strbuf_splice(&qname, 0, cp - qname.buf, "...", 3);
2242         }
2243
2244         if (patch->is_binary) {
2245                 printf(" %-*s |  Bin\n", max, qname.buf);
2246                 strbuf_release(&qname);
2247                 return;
2248         }
2249
2250         printf(" %-*s |", max, qname.buf);
2251         strbuf_release(&qname);
2252
2253         /*
2254          * scale the add/delete
2255          */
2256         max = max + state->max_change > 70 ? 70 - max : state->max_change;
2257         add = patch->lines_added;
2258         del = patch->lines_deleted;
2259
2260         if (state->max_change > 0) {
2261                 int total = ((add + del) * max + state->max_change / 2) / state->max_change;
2262                 add = (add * max + state->max_change / 2) / state->max_change;
2263                 del = total - add;
2264         }
2265         printf("%5d %.*s%.*s\n", patch->lines_added + patch->lines_deleted,
2266                 add, pluses, del, minuses);
2267 }
2268
2269 static int read_old_data(struct stat *st, const char *path, struct strbuf *buf)
2270 {
2271         switch (st->st_mode & S_IFMT) {
2272         case S_IFLNK:
2273                 if (strbuf_readlink(buf, path, st->st_size) < 0)
2274                         return error(_("unable to read symlink %s"), path);
2275                 return 0;
2276         case S_IFREG:
2277                 if (strbuf_read_file(buf, path, st->st_size) != st->st_size)
2278                         return error(_("unable to open or read %s"), path);
2279                 convert_to_git(path, buf->buf, buf->len, buf, 0);
2280                 return 0;
2281         default:
2282                 return -1;
2283         }
2284 }
2285
2286 /*
2287  * Update the preimage, and the common lines in postimage,
2288  * from buffer buf of length len. If postlen is 0 the postimage
2289  * is updated in place, otherwise it's updated on a new buffer
2290  * of length postlen
2291  */
2292
2293 static void update_pre_post_images(struct image *preimage,
2294                                    struct image *postimage,
2295                                    char *buf,
2296                                    size_t len, size_t postlen)
2297 {
2298         int i, ctx, reduced;
2299         char *new, *old, *fixed;
2300         struct image fixed_preimage;
2301
2302         /*
2303          * Update the preimage with whitespace fixes.  Note that we
2304          * are not losing preimage->buf -- apply_one_fragment() will
2305          * free "oldlines".
2306          */
2307         prepare_image(&fixed_preimage, buf, len, 1);
2308         assert(postlen
2309                ? fixed_preimage.nr == preimage->nr
2310                : fixed_preimage.nr <= preimage->nr);
2311         for (i = 0; i < fixed_preimage.nr; i++)
2312                 fixed_preimage.line[i].flag = preimage->line[i].flag;
2313         free(preimage->line_allocated);
2314         *preimage = fixed_preimage;
2315
2316         /*
2317          * Adjust the common context lines in postimage. This can be
2318          * done in-place when we are shrinking it with whitespace
2319          * fixing, but needs a new buffer when ignoring whitespace or
2320          * expanding leading tabs to spaces.
2321          *
2322          * We trust the caller to tell us if the update can be done
2323          * in place (postlen==0) or not.
2324          */
2325         old = postimage->buf;
2326         if (postlen)
2327                 new = postimage->buf = xmalloc(postlen);
2328         else
2329                 new = old;
2330         fixed = preimage->buf;
2331
2332         for (i = reduced = ctx = 0; i < postimage->nr; i++) {
2333                 size_t l_len = postimage->line[i].len;
2334                 if (!(postimage->line[i].flag & LINE_COMMON)) {
2335                         /* an added line -- no counterparts in preimage */
2336                         memmove(new, old, l_len);
2337                         old += l_len;
2338                         new += l_len;
2339                         continue;
2340                 }
2341
2342                 /* a common context -- skip it in the original postimage */
2343                 old += l_len;
2344
2345                 /* and find the corresponding one in the fixed preimage */
2346                 while (ctx < preimage->nr &&
2347                        !(preimage->line[ctx].flag & LINE_COMMON)) {
2348                         fixed += preimage->line[ctx].len;
2349                         ctx++;
2350                 }
2351
2352                 /*
2353                  * preimage is expected to run out, if the caller
2354                  * fixed addition of trailing blank lines.
2355                  */
2356                 if (preimage->nr <= ctx) {
2357                         reduced++;
2358                         continue;
2359                 }
2360
2361                 /* and copy it in, while fixing the line length */
2362                 l_len = preimage->line[ctx].len;
2363                 memcpy(new, fixed, l_len);
2364                 new += l_len;
2365                 fixed += l_len;
2366                 postimage->line[i].len = l_len;
2367                 ctx++;
2368         }
2369
2370         if (postlen
2371             ? postlen < new - postimage->buf
2372             : postimage->len < new - postimage->buf)
2373                 die("BUG: caller miscounted postlen: asked %d, orig = %d, used = %d",
2374                     (int)postlen, (int) postimage->len, (int)(new - postimage->buf));
2375
2376         /* Fix the length of the whole thing */
2377         postimage->len = new - postimage->buf;
2378         postimage->nr -= reduced;
2379 }
2380
2381 static int line_by_line_fuzzy_match(struct image *img,
2382                                     struct image *preimage,
2383                                     struct image *postimage,
2384                                     unsigned long try,
2385                                     int try_lno,
2386                                     int preimage_limit)
2387 {
2388         int i;
2389         size_t imgoff = 0;
2390         size_t preoff = 0;
2391         size_t postlen = postimage->len;
2392         size_t extra_chars;
2393         char *buf;
2394         char *preimage_eof;
2395         char *preimage_end;
2396         struct strbuf fixed;
2397         char *fixed_buf;
2398         size_t fixed_len;
2399
2400         for (i = 0; i < preimage_limit; i++) {
2401                 size_t prelen = preimage->line[i].len;
2402                 size_t imglen = img->line[try_lno+i].len;
2403
2404                 if (!fuzzy_matchlines(img->buf + try + imgoff, imglen,
2405                                       preimage->buf + preoff, prelen))
2406                         return 0;
2407                 if (preimage->line[i].flag & LINE_COMMON)
2408                         postlen += imglen - prelen;
2409                 imgoff += imglen;
2410                 preoff += prelen;
2411         }
2412
2413         /*
2414          * Ok, the preimage matches with whitespace fuzz.
2415          *
2416          * imgoff now holds the true length of the target that
2417          * matches the preimage before the end of the file.
2418          *
2419          * Count the number of characters in the preimage that fall
2420          * beyond the end of the file and make sure that all of them
2421          * are whitespace characters. (This can only happen if
2422          * we are removing blank lines at the end of the file.)
2423          */
2424         buf = preimage_eof = preimage->buf + preoff;
2425         for ( ; i < preimage->nr; i++)
2426                 preoff += preimage->line[i].len;
2427         preimage_end = preimage->buf + preoff;
2428         for ( ; buf < preimage_end; buf++)
2429                 if (!isspace(*buf))
2430                         return 0;
2431
2432         /*
2433          * Update the preimage and the common postimage context
2434          * lines to use the same whitespace as the target.
2435          * If whitespace is missing in the target (i.e.
2436          * if the preimage extends beyond the end of the file),
2437          * use the whitespace from the preimage.
2438          */
2439         extra_chars = preimage_end - preimage_eof;
2440         strbuf_init(&fixed, imgoff + extra_chars);
2441         strbuf_add(&fixed, img->buf + try, imgoff);
2442         strbuf_add(&fixed, preimage_eof, extra_chars);
2443         fixed_buf = strbuf_detach(&fixed, &fixed_len);
2444         update_pre_post_images(preimage, postimage,
2445                                fixed_buf, fixed_len, postlen);
2446         return 1;
2447 }
2448
2449 static int match_fragment(struct apply_state *state,
2450                           struct image *img,
2451                           struct image *preimage,
2452                           struct image *postimage,
2453                           unsigned long try,
2454                           int try_lno,
2455                           unsigned ws_rule,
2456                           int match_beginning, int match_end)
2457 {
2458         int i;
2459         char *fixed_buf, *buf, *orig, *target;
2460         struct strbuf fixed;
2461         size_t fixed_len, postlen;
2462         int preimage_limit;
2463
2464         if (preimage->nr + try_lno <= img->nr) {
2465                 /*
2466                  * The hunk falls within the boundaries of img.
2467                  */
2468                 preimage_limit = preimage->nr;
2469                 if (match_end && (preimage->nr + try_lno != img->nr))
2470                         return 0;
2471         } else if (state->ws_error_action == correct_ws_error &&
2472                    (ws_rule & WS_BLANK_AT_EOF)) {
2473                 /*
2474                  * This hunk extends beyond the end of img, and we are
2475                  * removing blank lines at the end of the file.  This
2476                  * many lines from the beginning of the preimage must
2477                  * match with img, and the remainder of the preimage
2478                  * must be blank.
2479                  */
2480                 preimage_limit = img->nr - try_lno;
2481         } else {
2482                 /*
2483                  * The hunk extends beyond the end of the img and
2484                  * we are not removing blanks at the end, so we
2485                  * should reject the hunk at this position.
2486                  */
2487                 return 0;
2488         }
2489
2490         if (match_beginning && try_lno)
2491                 return 0;
2492
2493         /* Quick hash check */
2494         for (i = 0; i < preimage_limit; i++)
2495                 if ((img->line[try_lno + i].flag & LINE_PATCHED) ||
2496                     (preimage->line[i].hash != img->line[try_lno + i].hash))
2497                         return 0;
2498
2499         if (preimage_limit == preimage->nr) {
2500                 /*
2501                  * Do we have an exact match?  If we were told to match
2502                  * at the end, size must be exactly at try+fragsize,
2503                  * otherwise try+fragsize must be still within the preimage,
2504                  * and either case, the old piece should match the preimage
2505                  * exactly.
2506                  */
2507                 if ((match_end
2508                      ? (try + preimage->len == img->len)
2509                      : (try + preimage->len <= img->len)) &&
2510                     !memcmp(img->buf + try, preimage->buf, preimage->len))
2511                         return 1;
2512         } else {
2513                 /*
2514                  * The preimage extends beyond the end of img, so
2515                  * there cannot be an exact match.
2516                  *
2517                  * There must be one non-blank context line that match
2518                  * a line before the end of img.
2519                  */
2520                 char *buf_end;
2521
2522                 buf = preimage->buf;
2523                 buf_end = buf;
2524                 for (i = 0; i < preimage_limit; i++)
2525                         buf_end += preimage->line[i].len;
2526
2527                 for ( ; buf < buf_end; buf++)
2528                         if (!isspace(*buf))
2529                                 break;
2530                 if (buf == buf_end)
2531                         return 0;
2532         }
2533
2534         /*
2535          * No exact match. If we are ignoring whitespace, run a line-by-line
2536          * fuzzy matching. We collect all the line length information because
2537          * we need it to adjust whitespace if we match.
2538          */
2539         if (state->ws_ignore_action == ignore_ws_change)
2540                 return line_by_line_fuzzy_match(img, preimage, postimage,
2541                                                 try, try_lno, preimage_limit);
2542
2543         if (state->ws_error_action != correct_ws_error)
2544                 return 0;
2545
2546         /*
2547          * The hunk does not apply byte-by-byte, but the hash says
2548          * it might with whitespace fuzz. We weren't asked to
2549          * ignore whitespace, we were asked to correct whitespace
2550          * errors, so let's try matching after whitespace correction.
2551          *
2552          * While checking the preimage against the target, whitespace
2553          * errors in both fixed, we count how large the corresponding
2554          * postimage needs to be.  The postimage prepared by
2555          * apply_one_fragment() has whitespace errors fixed on added
2556          * lines already, but the common lines were propagated as-is,
2557          * which may become longer when their whitespace errors are
2558          * fixed.
2559          */
2560
2561         /* First count added lines in postimage */
2562         postlen = 0;
2563         for (i = 0; i < postimage->nr; i++) {
2564                 if (!(postimage->line[i].flag & LINE_COMMON))
2565                         postlen += postimage->line[i].len;
2566         }
2567
2568         /*
2569          * The preimage may extend beyond the end of the file,
2570          * but in this loop we will only handle the part of the
2571          * preimage that falls within the file.
2572          */
2573         strbuf_init(&fixed, preimage->len + 1);
2574         orig = preimage->buf;
2575         target = img->buf + try;
2576         for (i = 0; i < preimage_limit; i++) {
2577                 size_t oldlen = preimage->line[i].len;
2578                 size_t tgtlen = img->line[try_lno + i].len;
2579                 size_t fixstart = fixed.len;
2580                 struct strbuf tgtfix;
2581                 int match;
2582
2583                 /* Try fixing the line in the preimage */
2584                 ws_fix_copy(&fixed, orig, oldlen, ws_rule, NULL);
2585
2586                 /* Try fixing the line in the target */
2587                 strbuf_init(&tgtfix, tgtlen);
2588                 ws_fix_copy(&tgtfix, target, tgtlen, ws_rule, NULL);
2589
2590                 /*
2591                  * If they match, either the preimage was based on
2592                  * a version before our tree fixed whitespace breakage,
2593                  * or we are lacking a whitespace-fix patch the tree
2594                  * the preimage was based on already had (i.e. target
2595                  * has whitespace breakage, the preimage doesn't).
2596                  * In either case, we are fixing the whitespace breakages
2597                  * so we might as well take the fix together with their
2598                  * real change.
2599                  */
2600                 match = (tgtfix.len == fixed.len - fixstart &&
2601                          !memcmp(tgtfix.buf, fixed.buf + fixstart,
2602                                              fixed.len - fixstart));
2603
2604                 /* Add the length if this is common with the postimage */
2605                 if (preimage->line[i].flag & LINE_COMMON)
2606                         postlen += tgtfix.len;
2607
2608                 strbuf_release(&tgtfix);
2609                 if (!match)
2610                         goto unmatch_exit;
2611
2612                 orig += oldlen;
2613                 target += tgtlen;
2614         }
2615
2616
2617         /*
2618          * Now handle the lines in the preimage that falls beyond the
2619          * end of the file (if any). They will only match if they are
2620          * empty or only contain whitespace (if WS_BLANK_AT_EOL is
2621          * false).
2622          */
2623         for ( ; i < preimage->nr; i++) {
2624                 size_t fixstart = fixed.len; /* start of the fixed preimage */
2625                 size_t oldlen = preimage->line[i].len;
2626                 int j;
2627
2628                 /* Try fixing the line in the preimage */
2629                 ws_fix_copy(&fixed, orig, oldlen, ws_rule, NULL);
2630
2631                 for (j = fixstart; j < fixed.len; j++)
2632                         if (!isspace(fixed.buf[j]))
2633                                 goto unmatch_exit;
2634
2635                 orig += oldlen;
2636         }
2637
2638         /*
2639          * Yes, the preimage is based on an older version that still
2640          * has whitespace breakages unfixed, and fixing them makes the
2641          * hunk match.  Update the context lines in the postimage.
2642          */
2643         fixed_buf = strbuf_detach(&fixed, &fixed_len);
2644         if (postlen < postimage->len)
2645                 postlen = 0;
2646         update_pre_post_images(preimage, postimage,
2647                                fixed_buf, fixed_len, postlen);
2648         return 1;
2649
2650  unmatch_exit:
2651         strbuf_release(&fixed);
2652         return 0;
2653 }
2654
2655 static int find_pos(struct apply_state *state,
2656                     struct image *img,
2657                     struct image *preimage,
2658                     struct image *postimage,
2659                     int line,
2660                     unsigned ws_rule,
2661                     int match_beginning, int match_end)
2662 {
2663         int i;
2664         unsigned long backwards, forwards, try;
2665         int backwards_lno, forwards_lno, try_lno;
2666
2667         /*
2668          * If match_beginning or match_end is specified, there is no
2669          * point starting from a wrong line that will never match and
2670          * wander around and wait for a match at the specified end.
2671          */
2672         if (match_beginning)
2673                 line = 0;
2674         else if (match_end)
2675                 line = img->nr - preimage->nr;
2676
2677         /*
2678          * Because the comparison is unsigned, the following test
2679          * will also take care of a negative line number that can
2680          * result when match_end and preimage is larger than the target.
2681          */
2682         if ((size_t) line > img->nr)
2683                 line = img->nr;
2684
2685         try = 0;
2686         for (i = 0; i < line; i++)
2687                 try += img->line[i].len;
2688
2689         /*
2690          * There's probably some smart way to do this, but I'll leave
2691          * that to the smart and beautiful people. I'm simple and stupid.
2692          */
2693         backwards = try;
2694         backwards_lno = line;
2695         forwards = try;
2696         forwards_lno = line;
2697         try_lno = line;
2698
2699         for (i = 0; ; i++) {
2700                 if (match_fragment(state, img, preimage, postimage,
2701                                    try, try_lno, ws_rule,
2702                                    match_beginning, match_end))
2703                         return try_lno;
2704
2705         again:
2706                 if (backwards_lno == 0 && forwards_lno == img->nr)
2707                         break;
2708
2709                 if (i & 1) {
2710                         if (backwards_lno == 0) {
2711                                 i++;
2712                                 goto again;
2713                         }
2714                         backwards_lno--;
2715                         backwards -= img->line[backwards_lno].len;
2716                         try = backwards;
2717                         try_lno = backwards_lno;
2718                 } else {
2719                         if (forwards_lno == img->nr) {
2720                                 i++;
2721                                 goto again;
2722                         }
2723                         forwards += img->line[forwards_lno].len;
2724                         forwards_lno++;
2725                         try = forwards;
2726                         try_lno = forwards_lno;
2727                 }
2728
2729         }
2730         return -1;
2731 }
2732
2733 static void remove_first_line(struct image *img)
2734 {
2735         img->buf += img->line[0].len;
2736         img->len -= img->line[0].len;
2737         img->line++;
2738         img->nr--;
2739 }
2740
2741 static void remove_last_line(struct image *img)
2742 {
2743         img->len -= img->line[--img->nr].len;
2744 }
2745
2746 /*
2747  * The change from "preimage" and "postimage" has been found to
2748  * apply at applied_pos (counts in line numbers) in "img".
2749  * Update "img" to remove "preimage" and replace it with "postimage".
2750  */
2751 static void update_image(struct apply_state *state,
2752                          struct image *img,
2753                          int applied_pos,
2754                          struct image *preimage,
2755                          struct image *postimage)
2756 {
2757         /*
2758          * remove the copy of preimage at offset in img
2759          * and replace it with postimage
2760          */
2761         int i, nr;
2762         size_t remove_count, insert_count, applied_at = 0;
2763         char *result;
2764         int preimage_limit;
2765
2766         /*
2767          * If we are removing blank lines at the end of img,
2768          * the preimage may extend beyond the end.
2769          * If that is the case, we must be careful only to
2770          * remove the part of the preimage that falls within
2771          * the boundaries of img. Initialize preimage_limit
2772          * to the number of lines in the preimage that falls
2773          * within the boundaries.
2774          */
2775         preimage_limit = preimage->nr;
2776         if (preimage_limit > img->nr - applied_pos)
2777                 preimage_limit = img->nr - applied_pos;
2778
2779         for (i = 0; i < applied_pos; i++)
2780                 applied_at += img->line[i].len;
2781
2782         remove_count = 0;
2783         for (i = 0; i < preimage_limit; i++)
2784                 remove_count += img->line[applied_pos + i].len;
2785         insert_count = postimage->len;
2786
2787         /* Adjust the contents */
2788         result = xmalloc(st_add3(st_sub(img->len, remove_count), insert_count, 1));
2789         memcpy(result, img->buf, applied_at);
2790         memcpy(result + applied_at, postimage->buf, postimage->len);
2791         memcpy(result + applied_at + postimage->len,
2792                img->buf + (applied_at + remove_count),
2793                img->len - (applied_at + remove_count));
2794         free(img->buf);
2795         img->buf = result;
2796         img->len += insert_count - remove_count;
2797         result[img->len] = '\0';
2798
2799         /* Adjust the line table */
2800         nr = img->nr + postimage->nr - preimage_limit;
2801         if (preimage_limit < postimage->nr) {
2802                 /*
2803                  * NOTE: this knows that we never call remove_first_line()
2804                  * on anything other than pre/post image.
2805                  */
2806                 REALLOC_ARRAY(img->line, nr);
2807                 img->line_allocated = img->line;
2808         }
2809         if (preimage_limit != postimage->nr)
2810                 memmove(img->line + applied_pos + postimage->nr,
2811                         img->line + applied_pos + preimage_limit,
2812                         (img->nr - (applied_pos + preimage_limit)) *
2813                         sizeof(*img->line));
2814         memcpy(img->line + applied_pos,
2815                postimage->line,
2816                postimage->nr * sizeof(*img->line));
2817         if (!state->allow_overlap)
2818                 for (i = 0; i < postimage->nr; i++)
2819                         img->line[applied_pos + i].flag |= LINE_PATCHED;
2820         img->nr = nr;
2821 }
2822
2823 /*
2824  * Use the patch-hunk text in "frag" to prepare two images (preimage and
2825  * postimage) for the hunk.  Find lines that match "preimage" in "img" and
2826  * replace the part of "img" with "postimage" text.
2827  */
2828 static int apply_one_fragment(struct apply_state *state,
2829                               struct image *img, struct fragment *frag,
2830                               int inaccurate_eof, unsigned ws_rule,
2831                               int nth_fragment)
2832 {
2833         int match_beginning, match_end;
2834         const char *patch = frag->patch;
2835         int size = frag->size;
2836         char *old, *oldlines;
2837         struct strbuf newlines;
2838         int new_blank_lines_at_end = 0;
2839         int found_new_blank_lines_at_end = 0;
2840         int hunk_linenr = frag->linenr;
2841         unsigned long leading, trailing;
2842         int pos, applied_pos;
2843         struct image preimage;
2844         struct image postimage;
2845
2846         memset(&preimage, 0, sizeof(preimage));
2847         memset(&postimage, 0, sizeof(postimage));
2848         oldlines = xmalloc(size);
2849         strbuf_init(&newlines, size);
2850
2851         old = oldlines;
2852         while (size > 0) {
2853                 char first;
2854                 int len = linelen(patch, size);
2855                 int plen;
2856                 int added_blank_line = 0;
2857                 int is_blank_context = 0;
2858                 size_t start;
2859
2860                 if (!len)
2861                         break;
2862
2863                 /*
2864                  * "plen" is how much of the line we should use for
2865                  * the actual patch data. Normally we just remove the
2866                  * first character on the line, but if the line is
2867                  * followed by "\ No newline", then we also remove the
2868                  * last one (which is the newline, of course).
2869                  */
2870                 plen = len - 1;
2871                 if (len < size && patch[len] == '\\')
2872                         plen--;
2873                 first = *patch;
2874                 if (state->apply_in_reverse) {
2875                         if (first == '-')
2876                                 first = '+';
2877                         else if (first == '+')
2878                                 first = '-';
2879                 }
2880
2881                 switch (first) {
2882                 case '\n':
2883                         /* Newer GNU diff, empty context line */
2884                         if (plen < 0)
2885                                 /* ... followed by '\No newline'; nothing */
2886                                 break;
2887                         *old++ = '\n';
2888                         strbuf_addch(&newlines, '\n');
2889                         add_line_info(&preimage, "\n", 1, LINE_COMMON);
2890                         add_line_info(&postimage, "\n", 1, LINE_COMMON);
2891                         is_blank_context = 1;
2892                         break;
2893                 case ' ':
2894                         if (plen && (ws_rule & WS_BLANK_AT_EOF) &&
2895                             ws_blank_line(patch + 1, plen, ws_rule))
2896                                 is_blank_context = 1;
2897                 case '-':
2898                         memcpy(old, patch + 1, plen);
2899                         add_line_info(&preimage, old, plen,
2900                                       (first == ' ' ? LINE_COMMON : 0));
2901                         old += plen;
2902                         if (first == '-')
2903                                 break;
2904                 /* Fall-through for ' ' */
2905                 case '+':
2906                         /* --no-add does not add new lines */
2907                         if (first == '+' && state->no_add)
2908                                 break;
2909
2910                         start = newlines.len;
2911                         if (first != '+' ||
2912                             !state->whitespace_error ||
2913                             state->ws_error_action != correct_ws_error) {
2914                                 strbuf_add(&newlines, patch + 1, plen);
2915                         }
2916                         else {
2917                                 ws_fix_copy(&newlines, patch + 1, plen, ws_rule, &state->applied_after_fixing_ws);
2918                         }
2919                         add_line_info(&postimage, newlines.buf + start, newlines.len - start,
2920                                       (first == '+' ? 0 : LINE_COMMON));
2921                         if (first == '+' &&
2922                             (ws_rule & WS_BLANK_AT_EOF) &&
2923                             ws_blank_line(patch + 1, plen, ws_rule))
2924                                 added_blank_line = 1;
2925                         break;
2926                 case '@': case '\\':
2927                         /* Ignore it, we already handled it */
2928                         break;
2929                 default:
2930                         if (state->apply_verbosity > verbosity_normal)
2931                                 error(_("invalid start of line: '%c'"), first);
2932                         applied_pos = -1;
2933                         goto out;
2934                 }
2935                 if (added_blank_line) {
2936                         if (!new_blank_lines_at_end)
2937                                 found_new_blank_lines_at_end = hunk_linenr;
2938                         new_blank_lines_at_end++;
2939                 }
2940                 else if (is_blank_context)
2941                         ;
2942                 else
2943                         new_blank_lines_at_end = 0;
2944                 patch += len;
2945                 size -= len;
2946                 hunk_linenr++;
2947         }
2948         if (inaccurate_eof &&
2949             old > oldlines && old[-1] == '\n' &&
2950             newlines.len > 0 && newlines.buf[newlines.len - 1] == '\n') {
2951                 old--;
2952                 strbuf_setlen(&newlines, newlines.len - 1);
2953         }
2954
2955         leading = frag->leading;
2956         trailing = frag->trailing;
2957
2958         /*
2959          * A hunk to change lines at the beginning would begin with
2960          * @@ -1,L +N,M @@
2961          * but we need to be careful.  -U0 that inserts before the second
2962          * line also has this pattern.
2963          *
2964          * And a hunk to add to an empty file would begin with
2965          * @@ -0,0 +N,M @@
2966          *
2967          * In other words, a hunk that is (frag->oldpos <= 1) with or
2968          * without leading context must match at the beginning.
2969          */
2970         match_beginning = (!frag->oldpos ||
2971                            (frag->oldpos == 1 && !state->unidiff_zero));
2972
2973         /*
2974          * A hunk without trailing lines must match at the end.
2975          * However, we simply cannot tell if a hunk must match end
2976          * from the lack of trailing lines if the patch was generated
2977          * with unidiff without any context.
2978          */
2979         match_end = !state->unidiff_zero && !trailing;
2980
2981         pos = frag->newpos ? (frag->newpos - 1) : 0;
2982         preimage.buf = oldlines;
2983         preimage.len = old - oldlines;
2984         postimage.buf = newlines.buf;
2985         postimage.len = newlines.len;
2986         preimage.line = preimage.line_allocated;
2987         postimage.line = postimage.line_allocated;
2988
2989         for (;;) {
2990
2991                 applied_pos = find_pos(state, img, &preimage, &postimage, pos,
2992                                        ws_rule, match_beginning, match_end);
2993
2994                 if (applied_pos >= 0)
2995                         break;
2996
2997                 /* Am I at my context limits? */
2998                 if ((leading <= state->p_context) && (trailing <= state->p_context))
2999                         break;
3000                 if (match_beginning || match_end) {
3001                         match_beginning = match_end = 0;
3002                         continue;
3003                 }
3004
3005                 /*
3006                  * Reduce the number of context lines; reduce both
3007                  * leading and trailing if they are equal otherwise
3008                  * just reduce the larger context.
3009                  */
3010                 if (leading >= trailing) {
3011                         remove_first_line(&preimage);
3012                         remove_first_line(&postimage);
3013                         pos--;
3014                         leading--;
3015                 }
3016                 if (trailing > leading) {
3017                         remove_last_line(&preimage);
3018                         remove_last_line(&postimage);
3019                         trailing--;
3020                 }
3021         }
3022
3023         if (applied_pos >= 0) {
3024                 if (new_blank_lines_at_end &&
3025                     preimage.nr + applied_pos >= img->nr &&
3026                     (ws_rule & WS_BLANK_AT_EOF) &&
3027                     state->ws_error_action != nowarn_ws_error) {
3028                         record_ws_error(state, WS_BLANK_AT_EOF, "+", 1,
3029                                         found_new_blank_lines_at_end);
3030                         if (state->ws_error_action == correct_ws_error) {
3031                                 while (new_blank_lines_at_end--)
3032                                         remove_last_line(&postimage);
3033                         }
3034                         /*
3035                          * We would want to prevent write_out_results()
3036                          * from taking place in apply_patch() that follows
3037                          * the callchain led us here, which is:
3038                          * apply_patch->check_patch_list->check_patch->
3039                          * apply_data->apply_fragments->apply_one_fragment
3040                          */
3041                         if (state->ws_error_action == die_on_ws_error)
3042                                 state->apply = 0;
3043                 }
3044
3045                 if (state->apply_verbosity > verbosity_normal && applied_pos != pos) {
3046                         int offset = applied_pos - pos;
3047                         if (state->apply_in_reverse)
3048                                 offset = 0 - offset;
3049                         fprintf_ln(stderr,
3050                                    Q_("Hunk #%d succeeded at %d (offset %d line).",
3051                                       "Hunk #%d succeeded at %d (offset %d lines).",
3052                                       offset),
3053                                    nth_fragment, applied_pos + 1, offset);
3054                 }
3055
3056                 /*
3057                  * Warn if it was necessary to reduce the number
3058                  * of context lines.
3059                  */
3060                 if ((leading != frag->leading ||
3061                      trailing != frag->trailing) && state->apply_verbosity > verbosity_silent)
3062                         fprintf_ln(stderr, _("Context reduced to (%ld/%ld)"
3063                                              " to apply fragment at %d"),
3064                                    leading, trailing, applied_pos+1);
3065                 update_image(state, img, applied_pos, &preimage, &postimage);
3066         } else {
3067                 if (state->apply_verbosity > verbosity_normal)
3068                         error(_("while searching for:\n%.*s"),
3069                               (int)(old - oldlines), oldlines);
3070         }
3071
3072 out:
3073         free(oldlines);
3074         strbuf_release(&newlines);
3075         free(preimage.line_allocated);
3076         free(postimage.line_allocated);
3077
3078         return (applied_pos < 0);
3079 }
3080
3081 static int apply_binary_fragment(struct apply_state *state,
3082                                  struct image *img,
3083                                  struct patch *patch)
3084 {
3085         struct fragment *fragment = patch->fragments;
3086         unsigned long len;
3087         void *dst;
3088
3089         if (!fragment)
3090                 return error(_("missing binary patch data for '%s'"),
3091                              patch->new_name ?
3092                              patch->new_name :
3093                              patch->old_name);
3094
3095         /* Binary patch is irreversible without the optional second hunk */
3096         if (state->apply_in_reverse) {
3097                 if (!fragment->next)
3098                         return error(_("cannot reverse-apply a binary patch "
3099                                        "without the reverse hunk to '%s'"),
3100                                      patch->new_name
3101                                      ? patch->new_name : patch->old_name);
3102                 fragment = fragment->next;
3103         }
3104         switch (fragment->binary_patch_method) {
3105         case BINARY_DELTA_DEFLATED:
3106                 dst = patch_delta(img->buf, img->len, fragment->patch,
3107                                   fragment->size, &len);
3108                 if (!dst)
3109                         return -1;
3110                 clear_image(img);
3111                 img->buf = dst;
3112                 img->len = len;
3113                 return 0;
3114         case BINARY_LITERAL_DEFLATED:
3115                 clear_image(img);
3116                 img->len = fragment->size;
3117                 img->buf = xmemdupz(fragment->patch, img->len);
3118                 return 0;
3119         }
3120         return -1;
3121 }
3122
3123 /*
3124  * Replace "img" with the result of applying the binary patch.
3125  * The binary patch data itself in patch->fragment is still kept
3126  * but the preimage prepared by the caller in "img" is freed here
3127  * or in the helper function apply_binary_fragment() this calls.
3128  */
3129 static int apply_binary(struct apply_state *state,
3130                         struct image *img,
3131                         struct patch *patch)
3132 {
3133         const char *name = patch->old_name ? patch->old_name : patch->new_name;
3134         struct object_id oid;
3135
3136         /*
3137          * For safety, we require patch index line to contain
3138          * full 40-byte textual SHA1 for old and new, at least for now.
3139          */
3140         if (strlen(patch->old_sha1_prefix) != 40 ||
3141             strlen(patch->new_sha1_prefix) != 40 ||
3142             get_oid_hex(patch->old_sha1_prefix, &oid) ||
3143             get_oid_hex(patch->new_sha1_prefix, &oid))
3144                 return error(_("cannot apply binary patch to '%s' "
3145                                "without full index line"), name);
3146
3147         if (patch->old_name) {
3148                 /*
3149                  * See if the old one matches what the patch
3150                  * applies to.
3151                  */
3152                 hash_sha1_file(img->buf, img->len, blob_type, oid.hash);
3153                 if (strcmp(oid_to_hex(&oid), patch->old_sha1_prefix))
3154                         return error(_("the patch applies to '%s' (%s), "
3155                                        "which does not match the "
3156                                        "current contents."),
3157                                      name, oid_to_hex(&oid));
3158         }
3159         else {
3160                 /* Otherwise, the old one must be empty. */
3161                 if (img->len)
3162                         return error(_("the patch applies to an empty "
3163                                        "'%s' but it is not empty"), name);
3164         }
3165
3166         get_oid_hex(patch->new_sha1_prefix, &oid);
3167         if (is_null_oid(&oid)) {
3168                 clear_image(img);
3169                 return 0; /* deletion patch */
3170         }
3171
3172         if (has_sha1_file(oid.hash)) {
3173                 /* We already have the postimage */
3174                 enum object_type type;
3175                 unsigned long size;
3176                 char *result;
3177
3178                 result = read_sha1_file(oid.hash, &type, &size);
3179                 if (!result)
3180                         return error(_("the necessary postimage %s for "
3181                                        "'%s' cannot be read"),
3182                                      patch->new_sha1_prefix, name);
3183                 clear_image(img);
3184                 img->buf = result;
3185                 img->len = size;
3186         } else {
3187                 /*
3188                  * We have verified buf matches the preimage;
3189                  * apply the patch data to it, which is stored
3190                  * in the patch->fragments->{patch,size}.
3191                  */
3192                 if (apply_binary_fragment(state, img, patch))
3193                         return error(_("binary patch does not apply to '%s'"),
3194                                      name);
3195
3196                 /* verify that the result matches */
3197                 hash_sha1_file(img->buf, img->len, blob_type, oid.hash);
3198                 if (strcmp(oid_to_hex(&oid), patch->new_sha1_prefix))
3199                         return error(_("binary patch to '%s' creates incorrect result (expecting %s, got %s)"),
3200                                 name, patch->new_sha1_prefix, oid_to_hex(&oid));
3201         }
3202
3203         return 0;
3204 }
3205
3206 static int apply_fragments(struct apply_state *state, struct image *img, struct patch *patch)
3207 {
3208         struct fragment *frag = patch->fragments;
3209         const char *name = patch->old_name ? patch->old_name : patch->new_name;
3210         unsigned ws_rule = patch->ws_rule;
3211         unsigned inaccurate_eof = patch->inaccurate_eof;
3212         int nth = 0;
3213
3214         if (patch->is_binary)
3215                 return apply_binary(state, img, patch);
3216
3217         while (frag) {
3218                 nth++;
3219                 if (apply_one_fragment(state, img, frag, inaccurate_eof, ws_rule, nth)) {
3220                         error(_("patch failed: %s:%ld"), name, frag->oldpos);
3221                         if (!state->apply_with_reject)
3222                                 return -1;
3223                         frag->rejected = 1;
3224                 }
3225                 frag = frag->next;
3226         }
3227         return 0;
3228 }
3229
3230 static int read_blob_object(struct strbuf *buf, const struct object_id *oid, unsigned mode)
3231 {
3232         if (S_ISGITLINK(mode)) {
3233                 strbuf_grow(buf, 100);
3234                 strbuf_addf(buf, "Subproject commit %s\n", oid_to_hex(oid));
3235         } else {
3236                 enum object_type type;
3237                 unsigned long sz;
3238                 char *result;
3239
3240                 result = read_sha1_file(oid->hash, &type, &sz);
3241                 if (!result)
3242                         return -1;
3243                 /* XXX read_sha1_file NUL-terminates */
3244                 strbuf_attach(buf, result, sz, sz + 1);
3245         }
3246         return 0;
3247 }
3248
3249 static int read_file_or_gitlink(const struct cache_entry *ce, struct strbuf *buf)
3250 {
3251         if (!ce)
3252                 return 0;
3253         return read_blob_object(buf, &ce->oid, ce->ce_mode);
3254 }
3255
3256 static struct patch *in_fn_table(struct apply_state *state, const char *name)
3257 {
3258         struct string_list_item *item;
3259
3260         if (name == NULL)
3261                 return NULL;
3262
3263         item = string_list_lookup(&state->fn_table, name);
3264         if (item != NULL)
3265                 return (struct patch *)item->util;
3266
3267         return NULL;
3268 }
3269
3270 /*
3271  * item->util in the filename table records the status of the path.
3272  * Usually it points at a patch (whose result records the contents
3273  * of it after applying it), but it could be PATH_WAS_DELETED for a
3274  * path that a previously applied patch has already removed, or
3275  * PATH_TO_BE_DELETED for a path that a later patch would remove.
3276  *
3277  * The latter is needed to deal with a case where two paths A and B
3278  * are swapped by first renaming A to B and then renaming B to A;
3279  * moving A to B should not be prevented due to presence of B as we
3280  * will remove it in a later patch.
3281  */
3282 #define PATH_TO_BE_DELETED ((struct patch *) -2)
3283 #define PATH_WAS_DELETED ((struct patch *) -1)
3284
3285 static int to_be_deleted(struct patch *patch)
3286 {
3287         return patch == PATH_TO_BE_DELETED;
3288 }
3289
3290 static int was_deleted(struct patch *patch)
3291 {
3292         return patch == PATH_WAS_DELETED;
3293 }
3294
3295 static void add_to_fn_table(struct apply_state *state, struct patch *patch)
3296 {
3297         struct string_list_item *item;
3298
3299         /*
3300          * Always add new_name unless patch is a deletion
3301          * This should cover the cases for normal diffs,
3302          * file creations and copies
3303          */
3304         if (patch->new_name != NULL) {
3305                 item = string_list_insert(&state->fn_table, patch->new_name);
3306                 item->util = patch;
3307         }
3308
3309         /*
3310          * store a failure on rename/deletion cases because
3311          * later chunks shouldn't patch old names
3312          */
3313         if ((patch->new_name == NULL) || (patch->is_rename)) {
3314                 item = string_list_insert(&state->fn_table, patch->old_name);
3315                 item->util = PATH_WAS_DELETED;
3316         }
3317 }
3318
3319 static void prepare_fn_table(struct apply_state *state, struct patch *patch)
3320 {
3321         /*
3322          * store information about incoming file deletion
3323          */
3324         while (patch) {
3325                 if ((patch->new_name == NULL) || (patch->is_rename)) {
3326                         struct string_list_item *item;
3327                         item = string_list_insert(&state->fn_table, patch->old_name);
3328                         item->util = PATH_TO_BE_DELETED;
3329                 }
3330                 patch = patch->next;
3331         }
3332 }
3333
3334 static int checkout_target(struct index_state *istate,
3335                            struct cache_entry *ce, struct stat *st)
3336 {
3337         struct checkout costate = CHECKOUT_INIT;
3338
3339         costate.refresh_cache = 1;
3340         costate.istate = istate;
3341         if (checkout_entry(ce, &costate, NULL) || lstat(ce->name, st))
3342                 return error(_("cannot checkout %s"), ce->name);
3343         return 0;
3344 }
3345
3346 static struct patch *previous_patch(struct apply_state *state,
3347                                     struct patch *patch,
3348                                     int *gone)
3349 {
3350         struct patch *previous;
3351
3352         *gone = 0;
3353         if (patch->is_copy || patch->is_rename)
3354                 return NULL; /* "git" patches do not depend on the order */
3355
3356         previous = in_fn_table(state, patch->old_name);
3357         if (!previous)
3358                 return NULL;
3359
3360         if (to_be_deleted(previous))
3361                 return NULL; /* the deletion hasn't happened yet */
3362
3363         if (was_deleted(previous))
3364                 *gone = 1;
3365
3366         return previous;
3367 }
3368
3369 static int verify_index_match(const struct cache_entry *ce, struct stat *st)
3370 {
3371         if (S_ISGITLINK(ce->ce_mode)) {
3372                 if (!S_ISDIR(st->st_mode))
3373                         return -1;
3374                 return 0;
3375         }
3376         return ce_match_stat(ce, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
3377 }
3378
3379 #define SUBMODULE_PATCH_WITHOUT_INDEX 1
3380
3381 static int load_patch_target(struct apply_state *state,
3382                              struct strbuf *buf,
3383                              const struct cache_entry *ce,
3384                              struct stat *st,
3385                              const char *name,
3386                              unsigned expected_mode)
3387 {
3388         if (state->cached || state->check_index) {
3389                 if (read_file_or_gitlink(ce, buf))
3390                         return error(_("failed to read %s"), name);
3391         } else if (name) {
3392                 if (S_ISGITLINK(expected_mode)) {
3393                         if (ce)
3394                                 return read_file_or_gitlink(ce, buf);
3395                         else
3396                                 return SUBMODULE_PATCH_WITHOUT_INDEX;
3397                 } else if (has_symlink_leading_path(name, strlen(name))) {
3398                         return error(_("reading from '%s' beyond a symbolic link"), name);
3399                 } else {
3400                         if (read_old_data(st, name, buf))
3401                                 return error(_("failed to read %s"), name);
3402                 }
3403         }
3404         return 0;
3405 }
3406
3407 /*
3408  * We are about to apply "patch"; populate the "image" with the
3409  * current version we have, from the working tree or from the index,
3410  * depending on the situation e.g. --cached/--index.  If we are
3411  * applying a non-git patch that incrementally updates the tree,
3412  * we read from the result of a previous diff.
3413  */
3414 static int load_preimage(struct apply_state *state,
3415                          struct image *image,
3416                          struct patch *patch, struct stat *st,
3417                          const struct cache_entry *ce)
3418 {
3419         struct strbuf buf = STRBUF_INIT;
3420         size_t len;
3421         char *img;
3422         struct patch *previous;
3423         int status;
3424
3425         previous = previous_patch(state, patch, &status);
3426         if (status)
3427                 return error(_("path %s has been renamed/deleted"),
3428                              patch->old_name);
3429         if (previous) {
3430                 /* We have a patched copy in memory; use that. */
3431                 strbuf_add(&buf, previous->result, previous->resultsize);
3432         } else {
3433                 status = load_patch_target(state, &buf, ce, st,
3434                                            patch->old_name, patch->old_mode);
3435                 if (status < 0)
3436                         return status;
3437                 else if (status == SUBMODULE_PATCH_WITHOUT_INDEX) {
3438                         /*
3439                          * There is no way to apply subproject
3440                          * patch without looking at the index.
3441                          * NEEDSWORK: shouldn't this be flagged
3442                          * as an error???
3443                          */
3444                         free_fragment_list(patch->fragments);
3445                         patch->fragments = NULL;
3446                 } else if (status) {
3447                         return error(_("failed to read %s"), patch->old_name);
3448                 }
3449         }
3450
3451         img = strbuf_detach(&buf, &len);
3452         prepare_image(image, img, len, !patch->is_binary);
3453         return 0;
3454 }
3455
3456 static int three_way_merge(struct image *image,
3457                            char *path,
3458                            const struct object_id *base,
3459                            const struct object_id *ours,
3460                            const struct object_id *theirs)
3461 {
3462         mmfile_t base_file, our_file, their_file;
3463         mmbuffer_t result = { NULL };
3464         int status;
3465
3466         read_mmblob(&base_file, base);
3467         read_mmblob(&our_file, ours);
3468         read_mmblob(&their_file, theirs);
3469         status = ll_merge(&result, path,
3470                           &base_file, "base",
3471                           &our_file, "ours",
3472                           &their_file, "theirs", NULL);
3473         free(base_file.ptr);
3474         free(our_file.ptr);
3475         free(their_file.ptr);
3476         if (status < 0 || !result.ptr) {
3477                 free(result.ptr);
3478                 return -1;
3479         }
3480         clear_image(image);
3481         image->buf = result.ptr;
3482         image->len = result.size;
3483
3484         return status;
3485 }
3486
3487 /*
3488  * When directly falling back to add/add three-way merge, we read from
3489  * the current contents of the new_name.  In no cases other than that
3490  * this function will be called.
3491  */
3492 static int load_current(struct apply_state *state,
3493                         struct image *image,
3494                         struct patch *patch)
3495 {
3496         struct strbuf buf = STRBUF_INIT;
3497         int status, pos;
3498         size_t len;
3499         char *img;
3500         struct stat st;
3501         struct cache_entry *ce;
3502         char *name = patch->new_name;
3503         unsigned mode = patch->new_mode;
3504
3505         if (!patch->is_new)
3506                 die("BUG: patch to %s is not a creation", patch->old_name);
3507
3508         pos = cache_name_pos(name, strlen(name));
3509         if (pos < 0)
3510                 return error(_("%s: does not exist in index"), name);
3511         ce = active_cache[pos];
3512         if (lstat(name, &st)) {
3513                 if (errno != ENOENT)
3514                         return error_errno("%s", name);
3515                 if (checkout_target(&the_index, ce, &st))
3516                         return -1;
3517         }
3518         if (verify_index_match(ce, &st))
3519                 return error(_("%s: does not match index"), name);
3520
3521         status = load_patch_target(state, &buf, ce, &st, name, mode);
3522         if (status < 0)
3523                 return status;
3524         else if (status)
3525                 return -1;
3526         img = strbuf_detach(&buf, &len);
3527         prepare_image(image, img, len, !patch->is_binary);
3528         return 0;
3529 }
3530
3531 static int try_threeway(struct apply_state *state,
3532                         struct image *image,
3533                         struct patch *patch,
3534                         struct stat *st,
3535                         const struct cache_entry *ce)
3536 {
3537         struct object_id pre_oid, post_oid, our_oid;
3538         struct strbuf buf = STRBUF_INIT;
3539         size_t len;
3540         int status;
3541         char *img;
3542         struct image tmp_image;
3543
3544         /* No point falling back to 3-way merge in these cases */
3545         if (patch->is_delete ||
3546             S_ISGITLINK(patch->old_mode) || S_ISGITLINK(patch->new_mode))
3547                 return -1;
3548
3549         /* Preimage the patch was prepared for */
3550         if (patch->is_new)
3551                 write_sha1_file("", 0, blob_type, pre_oid.hash);
3552         else if (get_sha1(patch->old_sha1_prefix, pre_oid.hash) ||
3553                  read_blob_object(&buf, &pre_oid, patch->old_mode))
3554                 return error(_("repository lacks the necessary blob to fall back on 3-way merge."));
3555
3556         if (state->apply_verbosity > verbosity_silent)
3557                 fprintf(stderr, _("Falling back to three-way merge...\n"));
3558
3559         img = strbuf_detach(&buf, &len);
3560         prepare_image(&tmp_image, img, len, 1);
3561         /* Apply the patch to get the post image */
3562         if (apply_fragments(state, &tmp_image, patch) < 0) {
3563                 clear_image(&tmp_image);
3564                 return -1;
3565         }
3566         /* post_oid is theirs */
3567         write_sha1_file(tmp_image.buf, tmp_image.len, blob_type, post_oid.hash);
3568         clear_image(&tmp_image);
3569
3570         /* our_oid is ours */
3571         if (patch->is_new) {
3572                 if (load_current(state, &tmp_image, patch))
3573                         return error(_("cannot read the current contents of '%s'"),
3574                                      patch->new_name);
3575         } else {
3576                 if (load_preimage(state, &tmp_image, patch, st, ce))
3577                         return error(_("cannot read the current contents of '%s'"),
3578                                      patch->old_name);
3579         }
3580         write_sha1_file(tmp_image.buf, tmp_image.len, blob_type, our_oid.hash);
3581         clear_image(&tmp_image);
3582
3583         /* in-core three-way merge between post and our using pre as base */
3584         status = three_way_merge(image, patch->new_name,
3585                                  &pre_oid, &our_oid, &post_oid);
3586         if (status < 0) {
3587                 if (state->apply_verbosity > verbosity_silent)
3588                         fprintf(stderr,
3589                                 _("Failed to fall back on three-way merge...\n"));
3590                 return status;
3591         }
3592
3593         if (status) {
3594                 patch->conflicted_threeway = 1;
3595                 if (patch->is_new)
3596                         oidclr(&patch->threeway_stage[0]);
3597                 else
3598                         oidcpy(&patch->threeway_stage[0], &pre_oid);
3599                 oidcpy(&patch->threeway_stage[1], &our_oid);
3600                 oidcpy(&patch->threeway_stage[2], &post_oid);
3601                 if (state->apply_verbosity > verbosity_silent)
3602                         fprintf(stderr,
3603                                 _("Applied patch to '%s' with conflicts.\n"),
3604                                 patch->new_name);
3605         } else {
3606                 if (state->apply_verbosity > verbosity_silent)
3607                         fprintf(stderr,
3608                                 _("Applied patch to '%s' cleanly.\n"),
3609                                 patch->new_name);
3610         }
3611         return 0;
3612 }
3613
3614 static int apply_data(struct apply_state *state, struct patch *patch,
3615                       struct stat *st, const struct cache_entry *ce)
3616 {
3617         struct image image;
3618
3619         if (load_preimage(state, &image, patch, st, ce) < 0)
3620                 return -1;
3621
3622         if (patch->direct_to_threeway ||
3623             apply_fragments(state, &image, patch) < 0) {
3624                 /* Note: with --reject, apply_fragments() returns 0 */
3625                 if (!state->threeway || try_threeway(state, &image, patch, st, ce) < 0)
3626                         return -1;
3627         }
3628         patch->result = image.buf;
3629         patch->resultsize = image.len;
3630         add_to_fn_table(state, patch);
3631         free(image.line_allocated);
3632
3633         if (0 < patch->is_delete && patch->resultsize)
3634                 return error(_("removal patch leaves file contents"));
3635
3636         return 0;
3637 }
3638
3639 /*
3640  * If "patch" that we are looking at modifies or deletes what we have,
3641  * we would want it not to lose any local modification we have, either
3642  * in the working tree or in the index.
3643  *
3644  * This also decides if a non-git patch is a creation patch or a
3645  * modification to an existing empty file.  We do not check the state
3646  * of the current tree for a creation patch in this function; the caller
3647  * check_patch() separately makes sure (and errors out otherwise) that
3648  * the path the patch creates does not exist in the current tree.
3649  */
3650 static int check_preimage(struct apply_state *state,
3651                           struct patch *patch,
3652                           struct cache_entry **ce,
3653                           struct stat *st)
3654 {
3655         const char *old_name = patch->old_name;
3656         struct patch *previous = NULL;
3657         int stat_ret = 0, status;
3658         unsigned st_mode = 0;
3659
3660         if (!old_name)
3661                 return 0;
3662
3663         assert(patch->is_new <= 0);
3664         previous = previous_patch(state, patch, &status);
3665
3666         if (status)
3667                 return error(_("path %s has been renamed/deleted"), old_name);
3668         if (previous) {
3669                 st_mode = previous->new_mode;
3670         } else if (!state->cached) {
3671                 stat_ret = lstat(old_name, st);
3672                 if (stat_ret && errno != ENOENT)
3673                         return error_errno("%s", old_name);
3674         }
3675
3676         if (state->check_index && !previous) {
3677                 int pos = cache_name_pos(old_name, strlen(old_name));
3678                 if (pos < 0) {
3679                         if (patch->is_new < 0)
3680                                 goto is_new;
3681                         return error(_("%s: does not exist in index"), old_name);
3682                 }
3683                 *ce = active_cache[pos];
3684                 if (stat_ret < 0) {
3685                         if (checkout_target(&the_index, *ce, st))
3686                                 return -1;
3687                 }
3688                 if (!state->cached && verify_index_match(*ce, st))
3689                         return error(_("%s: does not match index"), old_name);
3690                 if (state->cached)
3691                         st_mode = (*ce)->ce_mode;
3692         } else if (stat_ret < 0) {
3693                 if (patch->is_new < 0)
3694                         goto is_new;
3695                 return error_errno("%s", old_name);
3696         }
3697
3698         if (!state->cached && !previous)
3699                 st_mode = ce_mode_from_stat(*ce, st->st_mode);
3700
3701         if (patch->is_new < 0)
3702                 patch->is_new = 0;
3703         if (!patch->old_mode)
3704                 patch->old_mode = st_mode;
3705         if ((st_mode ^ patch->old_mode) & S_IFMT)
3706                 return error(_("%s: wrong type"), old_name);
3707         if (st_mode != patch->old_mode)
3708                 warning(_("%s has type %o, expected %o"),
3709                         old_name, st_mode, patch->old_mode);
3710         if (!patch->new_mode && !patch->is_delete)
3711                 patch->new_mode = st_mode;
3712         return 0;
3713
3714  is_new:
3715         patch->is_new = 1;
3716         patch->is_delete = 0;
3717         free(patch->old_name);
3718         patch->old_name = NULL;
3719         return 0;
3720 }
3721
3722
3723 #define EXISTS_IN_INDEX 1
3724 #define EXISTS_IN_WORKTREE 2
3725
3726 static int check_to_create(struct apply_state *state,
3727                            const char *new_name,
3728                            int ok_if_exists)
3729 {
3730         struct stat nst;
3731
3732         if (state->check_index &&
3733             cache_name_pos(new_name, strlen(new_name)) >= 0 &&
3734             !ok_if_exists)
3735                 return EXISTS_IN_INDEX;
3736         if (state->cached)
3737                 return 0;
3738
3739         if (!lstat(new_name, &nst)) {
3740                 if (S_ISDIR(nst.st_mode) || ok_if_exists)
3741                         return 0;
3742                 /*
3743                  * A leading component of new_name might be a symlink
3744                  * that is going to be removed with this patch, but
3745                  * still pointing at somewhere that has the path.
3746                  * In such a case, path "new_name" does not exist as
3747                  * far as git is concerned.
3748                  */
3749                 if (has_symlink_leading_path(new_name, strlen(new_name)))
3750                         return 0;
3751
3752                 return EXISTS_IN_WORKTREE;
3753         } else if ((errno != ENOENT) && (errno != ENOTDIR)) {
3754                 return error_errno("%s", new_name);
3755         }
3756         return 0;
3757 }
3758
3759 static uintptr_t register_symlink_changes(struct apply_state *state,
3760                                           const char *path,
3761                                           uintptr_t what)
3762 {
3763         struct string_list_item *ent;
3764
3765         ent = string_list_lookup(&state->symlink_changes, path);
3766         if (!ent) {
3767                 ent = string_list_insert(&state->symlink_changes, path);
3768                 ent->util = (void *)0;
3769         }
3770         ent->util = (void *)(what | ((uintptr_t)ent->util));
3771         return (uintptr_t)ent->util;
3772 }
3773
3774 static uintptr_t check_symlink_changes(struct apply_state *state, const char *path)
3775 {
3776         struct string_list_item *ent;
3777
3778         ent = string_list_lookup(&state->symlink_changes, path);
3779         if (!ent)
3780                 return 0;
3781         return (uintptr_t)ent->util;
3782 }
3783
3784 static void prepare_symlink_changes(struct apply_state *state, struct patch *patch)
3785 {
3786         for ( ; patch; patch = patch->next) {
3787                 if ((patch->old_name && S_ISLNK(patch->old_mode)) &&
3788                     (patch->is_rename || patch->is_delete))
3789                         /* the symlink at patch->old_name is removed */
3790                         register_symlink_changes(state, patch->old_name, APPLY_SYMLINK_GOES_AWAY);
3791
3792                 if (patch->new_name && S_ISLNK(patch->new_mode))
3793                         /* the symlink at patch->new_name is created or remains */
3794                         register_symlink_changes(state, patch->new_name, APPLY_SYMLINK_IN_RESULT);
3795         }
3796 }
3797
3798 static int path_is_beyond_symlink_1(struct apply_state *state, struct strbuf *name)
3799 {
3800         do {
3801                 unsigned int change;
3802
3803                 while (--name->len && name->buf[name->len] != '/')
3804                         ; /* scan backwards */
3805                 if (!name->len)
3806                         break;
3807                 name->buf[name->len] = '\0';
3808                 change = check_symlink_changes(state, name->buf);
3809                 if (change & APPLY_SYMLINK_IN_RESULT)
3810                         return 1;
3811                 if (change & APPLY_SYMLINK_GOES_AWAY)
3812                         /*
3813                          * This cannot be "return 0", because we may
3814                          * see a new one created at a higher level.
3815                          */
3816                         continue;
3817
3818                 /* otherwise, check the preimage */
3819                 if (state->check_index) {
3820                         struct cache_entry *ce;
3821
3822                         ce = cache_file_exists(name->buf, name->len, ignore_case);
3823                         if (ce && S_ISLNK(ce->ce_mode))
3824                                 return 1;
3825                 } else {
3826                         struct stat st;
3827                         if (!lstat(name->buf, &st) && S_ISLNK(st.st_mode))
3828                                 return 1;
3829                 }
3830         } while (1);
3831         return 0;
3832 }
3833
3834 static int path_is_beyond_symlink(struct apply_state *state, const char *name_)
3835 {
3836         int ret;
3837         struct strbuf name = STRBUF_INIT;
3838
3839         assert(*name_ != '\0');
3840         strbuf_addstr(&name, name_);
3841         ret = path_is_beyond_symlink_1(state, &name);
3842         strbuf_release(&name);
3843
3844         return ret;
3845 }
3846
3847 static int check_unsafe_path(struct patch *patch)
3848 {
3849         const char *old_name = NULL;
3850         const char *new_name = NULL;
3851         if (patch->is_delete)
3852                 old_name = patch->old_name;
3853         else if (!patch->is_new && !patch->is_copy)
3854                 old_name = patch->old_name;
3855         if (!patch->is_delete)
3856                 new_name = patch->new_name;
3857
3858         if (old_name && !verify_path(old_name))
3859                 return error(_("invalid path '%s'"), old_name);
3860         if (new_name && !verify_path(new_name))
3861                 return error(_("invalid path '%s'"), new_name);
3862         return 0;
3863 }
3864
3865 /*
3866  * Check and apply the patch in-core; leave the result in patch->result
3867  * for the caller to write it out to the final destination.
3868  */
3869 static int check_patch(struct apply_state *state, struct patch *patch)
3870 {
3871         struct stat st;
3872         const char *old_name = patch->old_name;
3873         const char *new_name = patch->new_name;
3874         const char *name = old_name ? old_name : new_name;
3875         struct cache_entry *ce = NULL;
3876         struct patch *tpatch;
3877         int ok_if_exists;
3878         int status;
3879
3880         patch->rejected = 1; /* we will drop this after we succeed */
3881
3882         status = check_preimage(state, patch, &ce, &st);
3883         if (status)
3884                 return status;
3885         old_name = patch->old_name;
3886
3887         /*
3888          * A type-change diff is always split into a patch to delete
3889          * old, immediately followed by a patch to create new (see
3890          * diff.c::run_diff()); in such a case it is Ok that the entry
3891          * to be deleted by the previous patch is still in the working
3892          * tree and in the index.
3893          *
3894          * A patch to swap-rename between A and B would first rename A
3895          * to B and then rename B to A.  While applying the first one,
3896          * the presence of B should not stop A from getting renamed to
3897          * B; ask to_be_deleted() about the later rename.  Removal of
3898          * B and rename from A to B is handled the same way by asking
3899          * was_deleted().
3900          */
3901         if ((tpatch = in_fn_table(state, new_name)) &&
3902             (was_deleted(tpatch) || to_be_deleted(tpatch)))
3903                 ok_if_exists = 1;
3904         else
3905                 ok_if_exists = 0;
3906
3907         if (new_name &&
3908             ((0 < patch->is_new) || patch->is_rename || patch->is_copy)) {
3909                 int err = check_to_create(state, new_name, ok_if_exists);
3910
3911                 if (err && state->threeway) {
3912                         patch->direct_to_threeway = 1;
3913                 } else switch (err) {
3914                 case 0:
3915                         break; /* happy */
3916                 case EXISTS_IN_INDEX:
3917                         return error(_("%s: already exists in index"), new_name);
3918                         break;
3919                 case EXISTS_IN_WORKTREE:
3920                         return error(_("%s: already exists in working directory"),
3921                                      new_name);
3922                 default:
3923                         return err;
3924                 }
3925
3926                 if (!patch->new_mode) {
3927                         if (0 < patch->is_new)
3928                                 patch->new_mode = S_IFREG | 0644;
3929                         else
3930                                 patch->new_mode = patch->old_mode;
3931                 }
3932         }
3933
3934         if (new_name && old_name) {
3935                 int same = !strcmp(old_name, new_name);
3936                 if (!patch->new_mode)
3937                         patch->new_mode = patch->old_mode;
3938                 if ((patch->old_mode ^ patch->new_mode) & S_IFMT) {
3939                         if (same)
3940                                 return error(_("new mode (%o) of %s does not "
3941                                                "match old mode (%o)"),
3942                                         patch->new_mode, new_name,
3943                                         patch->old_mode);
3944                         else
3945                                 return error(_("new mode (%o) of %s does not "
3946                                                "match old mode (%o) of %s"),
3947                                         patch->new_mode, new_name,
3948                                         patch->old_mode, old_name);
3949                 }
3950         }
3951
3952         if (!state->unsafe_paths && check_unsafe_path(patch))
3953                 return -128;
3954
3955         /*
3956          * An attempt to read from or delete a path that is beyond a
3957          * symbolic link will be prevented by load_patch_target() that
3958          * is called at the beginning of apply_data() so we do not
3959          * have to worry about a patch marked with "is_delete" bit
3960          * here.  We however need to make sure that the patch result
3961          * is not deposited to a path that is beyond a symbolic link
3962          * here.
3963          */
3964         if (!patch->is_delete && path_is_beyond_symlink(state, patch->new_name))
3965                 return error(_("affected file '%s' is beyond a symbolic link"),
3966                              patch->new_name);
3967
3968         if (apply_data(state, patch, &st, ce) < 0)
3969                 return error(_("%s: patch does not apply"), name);
3970         patch->rejected = 0;
3971         return 0;
3972 }
3973
3974 static int check_patch_list(struct apply_state *state, struct patch *patch)
3975 {
3976         int err = 0;
3977
3978         prepare_symlink_changes(state, patch);
3979         prepare_fn_table(state, patch);
3980         while (patch) {
3981                 int res;
3982                 if (state->apply_verbosity > verbosity_normal)
3983                         say_patch_name(stderr,
3984                                        _("Checking patch %s..."), patch);
3985                 res = check_patch(state, patch);
3986                 if (res == -128)
3987                         return -128;
3988                 err |= res;
3989                 patch = patch->next;
3990         }
3991         return err;
3992 }
3993
3994 static int read_apply_cache(struct apply_state *state)
3995 {
3996         if (state->index_file)
3997                 return read_cache_from(state->index_file);
3998         else
3999                 return read_cache();
4000 }
4001
4002 /* This function tries to read the object name from the current index */
4003 static int get_current_oid(struct apply_state *state, const char *path,
4004                            struct object_id *oid)
4005 {
4006         int pos;
4007
4008         if (read_apply_cache(state) < 0)
4009                 return -1;
4010         pos = cache_name_pos(path, strlen(path));
4011         if (pos < 0)
4012                 return -1;
4013         oidcpy(oid, &active_cache[pos]->oid);
4014         return 0;
4015 }
4016
4017 static int preimage_oid_in_gitlink_patch(struct patch *p, struct object_id *oid)
4018 {
4019         /*
4020          * A usable gitlink patch has only one fragment (hunk) that looks like:
4021          * @@ -1 +1 @@
4022          * -Subproject commit <old sha1>
4023          * +Subproject commit <new sha1>
4024          * or
4025          * @@ -1 +0,0 @@
4026          * -Subproject commit <old sha1>
4027          * for a removal patch.
4028          */
4029         struct fragment *hunk = p->fragments;
4030         static const char heading[] = "-Subproject commit ";
4031         char *preimage;
4032
4033         if (/* does the patch have only one hunk? */
4034             hunk && !hunk->next &&
4035             /* is its preimage one line? */
4036             hunk->oldpos == 1 && hunk->oldlines == 1 &&
4037             /* does preimage begin with the heading? */
4038             (preimage = memchr(hunk->patch, '\n', hunk->size)) != NULL &&
4039             starts_with(++preimage, heading) &&
4040             /* does it record full SHA-1? */
4041             !get_oid_hex(preimage + sizeof(heading) - 1, oid) &&
4042             preimage[sizeof(heading) + GIT_SHA1_HEXSZ - 1] == '\n' &&
4043             /* does the abbreviated name on the index line agree with it? */
4044             starts_with(preimage + sizeof(heading) - 1, p->old_sha1_prefix))
4045                 return 0; /* it all looks fine */
4046
4047         /* we may have full object name on the index line */
4048         return get_oid_hex(p->old_sha1_prefix, oid);
4049 }
4050
4051 /* Build an index that contains the just the files needed for a 3way merge */
4052 static int build_fake_ancestor(struct apply_state *state, struct patch *list)
4053 {
4054         struct patch *patch;
4055         struct index_state result = { NULL };
4056         static struct lock_file lock;
4057         int res;
4058
4059         /* Once we start supporting the reverse patch, it may be
4060          * worth showing the new sha1 prefix, but until then...
4061          */
4062         for (patch = list; patch; patch = patch->next) {
4063                 struct object_id oid;
4064                 struct cache_entry *ce;
4065                 const char *name;
4066
4067                 name = patch->old_name ? patch->old_name : patch->new_name;
4068                 if (0 < patch->is_new)
4069                         continue;
4070
4071                 if (S_ISGITLINK(patch->old_mode)) {
4072                         if (!preimage_oid_in_gitlink_patch(patch, &oid))
4073                                 ; /* ok, the textual part looks sane */
4074                         else
4075                                 return error(_("sha1 information is lacking or "
4076                                                "useless for submodule %s"), name);
4077                 } else if (!get_sha1_blob(patch->old_sha1_prefix, oid.hash)) {
4078                         ; /* ok */
4079                 } else if (!patch->lines_added && !patch->lines_deleted) {
4080                         /* mode-only change: update the current */
4081                         if (get_current_oid(state, patch->old_name, &oid))
4082                                 return error(_("mode change for %s, which is not "
4083                                                "in current HEAD"), name);
4084                 } else
4085                         return error(_("sha1 information is lacking or useless "
4086                                        "(%s)."), name);
4087
4088                 ce = make_cache_entry(patch->old_mode, oid.hash, name, 0, 0);
4089                 if (!ce)
4090                         return error(_("make_cache_entry failed for path '%s'"),
4091                                      name);
4092                 if (add_index_entry(&result, ce, ADD_CACHE_OK_TO_ADD)) {
4093                         free(ce);
4094                         return error(_("could not add %s to temporary index"),
4095                                      name);
4096                 }
4097         }
4098
4099         hold_lock_file_for_update(&lock, state->fake_ancestor, LOCK_DIE_ON_ERROR);
4100         res = write_locked_index(&result, &lock, COMMIT_LOCK);
4101         discard_index(&result);
4102
4103          if (res)
4104                  return error(_("could not write temporary index to %s"),
4105                               state->fake_ancestor);
4106
4107          return 0;
4108  }
4109
4110  static void stat_patch_list(struct apply_state *state, struct patch *patch)
4111  {
4112          int files, adds, dels;
4113
4114          for (files = adds = dels = 0 ; patch ; patch = patch->next) {
4115                  files++;
4116                  adds += patch->lines_added;
4117                  dels += patch->lines_deleted;
4118                  show_stats(state, patch);
4119          }
4120
4121          print_stat_summary(stdout, files, adds, dels);
4122  }
4123
4124  static void numstat_patch_list(struct apply_state *state,
4125                                 struct patch *patch)
4126  {
4127          for ( ; patch; patch = patch->next) {
4128                  const char *name;
4129                  name = patch->new_name ? patch->new_name : patch->old_name;
4130                  if (patch->is_binary)
4131                          printf("-\t-\t");
4132                  else
4133                          printf("%d\t%d\t", patch->lines_added, patch->lines_deleted);
4134                  write_name_quoted(name, stdout, state->line_termination);
4135          }
4136  }
4137
4138  static void show_file_mode_name(const char *newdelete, unsigned int mode, const char *name)
4139  {
4140          if (mode)
4141                  printf(" %s mode %06o %s\n", newdelete, mode, name);
4142          else
4143                  printf(" %s %s\n", newdelete, name);
4144  }
4145
4146  static void show_mode_change(struct patch *p, int show_name)
4147  {
4148          if (p->old_mode && p->new_mode && p->old_mode != p->new_mode) {
4149                  if (show_name)
4150                          printf(" mode change %06o => %06o %s\n",
4151                                 p->old_mode, p->new_mode, p->new_name);
4152                  else
4153                          printf(" mode change %06o => %06o\n",
4154                                 p->old_mode, p->new_mode);
4155          }
4156  }
4157
4158  static void show_rename_copy(struct patch *p)
4159  {
4160          const char *renamecopy = p->is_rename ? "rename" : "copy";
4161          const char *old, *new;
4162
4163          /* Find common prefix */
4164          old = p->old_name;
4165          new = p->new_name;
4166          while (1) {
4167                  const char *slash_old, *slash_new;
4168                  slash_old = strchr(old, '/');
4169                  slash_new = strchr(new, '/');
4170                  if (!slash_old ||
4171                      !slash_new ||
4172                      slash_old - old != slash_new - new ||
4173                      memcmp(old, new, slash_new - new))
4174                          break;
4175                  old = slash_old + 1;
4176                  new = slash_new + 1;
4177          }
4178          /* p->old_name thru old is the common prefix, and old and new
4179           * through the end of names are renames
4180           */
4181          if (old != p->old_name)
4182                  printf(" %s %.*s{%s => %s} (%d%%)\n", renamecopy,
4183                         (int)(old - p->old_name), p->old_name,
4184                         old, new, p->score);
4185          else
4186                  printf(" %s %s => %s (%d%%)\n", renamecopy,
4187                         p->old_name, p->new_name, p->score);
4188          show_mode_change(p, 0);
4189  }
4190
4191  static void summary_patch_list(struct patch *patch)
4192  {
4193          struct patch *p;
4194
4195          for (p = patch; p; p = p->next) {
4196                  if (p->is_new)
4197                          show_file_mode_name("create", p->new_mode, p->new_name);
4198                  else if (p->is_delete)
4199                          show_file_mode_name("delete", p->old_mode, p->old_name);
4200                  else {
4201                          if (p->is_rename || p->is_copy)
4202                                  show_rename_copy(p);
4203                          else {
4204                                  if (p->score) {
4205                                          printf(" rewrite %s (%d%%)\n",
4206                                                 p->new_name, p->score);
4207                                          show_mode_change(p, 0);
4208                                  }
4209                                  else
4210                                          show_mode_change(p, 1);
4211                          }
4212                  }
4213          }
4214  }
4215
4216  static void patch_stats(struct apply_state *state, struct patch *patch)
4217  {
4218          int lines = patch->lines_added + patch->lines_deleted;
4219
4220          if (lines > state->max_change)
4221                  state->max_change = lines;
4222          if (patch->old_name) {
4223                  int len = quote_c_style(patch->old_name, NULL, NULL, 0);
4224                  if (!len)
4225                          len = strlen(patch->old_name);
4226                  if (len > state->max_len)
4227                          state->max_len = len;
4228          }
4229          if (patch->new_name) {
4230                  int len = quote_c_style(patch->new_name, NULL, NULL, 0);
4231                  if (!len)
4232                          len = strlen(patch->new_name);
4233                  if (len > state->max_len)
4234                          state->max_len = len;
4235          }
4236  }
4237
4238  static int remove_file(struct apply_state *state, struct patch *patch, int rmdir_empty)
4239  {
4240          if (state->update_index) {
4241                  if (remove_file_from_cache(patch->old_name) < 0)
4242                          return error(_("unable to remove %s from index"), patch->old_name);
4243          }
4244          if (!state->cached) {
4245                  if (!remove_or_warn(patch->old_mode, patch->old_name) && rmdir_empty) {
4246                          remove_path(patch->old_name);
4247                  }
4248          }
4249          return 0;
4250  }
4251
4252  static int add_index_file(struct apply_state *state,
4253                            const char *path,
4254                            unsigned mode,
4255                            void *buf,
4256                            unsigned long size)
4257  {
4258          struct stat st;
4259          struct cache_entry *ce;
4260          int namelen = strlen(path);
4261          unsigned ce_size = cache_entry_size(namelen);
4262
4263          if (!state->update_index)
4264                  return 0;
4265
4266          ce = xcalloc(1, ce_size);
4267          memcpy(ce->name, path, namelen);
4268          ce->ce_mode = create_ce_mode(mode);
4269          ce->ce_flags = create_ce_flags(0);
4270          ce->ce_namelen = namelen;
4271          if (S_ISGITLINK(mode)) {
4272                  const char *s;
4273
4274                  if (!skip_prefix(buf, "Subproject commit ", &s) ||
4275                      get_oid_hex(s, &ce->oid)) {
4276                         free(ce);
4277                         return error(_("corrupt patch for submodule %s"), path);
4278                 }
4279         } else {
4280                 if (!state->cached) {
4281                         if (lstat(path, &st) < 0) {
4282                                 free(ce);
4283                                 return error_errno(_("unable to stat newly "
4284                                                      "created file '%s'"),
4285                                                    path);
4286                         }
4287                         fill_stat_cache_info(ce, &st);
4288                 }
4289                 if (write_sha1_file(buf, size, blob_type, ce->oid.hash) < 0) {
4290                         free(ce);
4291                         return error(_("unable to create backing store "
4292                                        "for newly created file %s"), path);
4293                 }
4294         }
4295         if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD) < 0) {
4296                 free(ce);
4297                 return error(_("unable to add cache entry for %s"), path);
4298         }
4299
4300         return 0;
4301 }
4302
4303 /*
4304  * Returns:
4305  *  -1 if an unrecoverable error happened
4306  *   0 if everything went well
4307  *   1 if a recoverable error happened
4308  */
4309 static int try_create_file(const char *path, unsigned int mode, const char *buf, unsigned long size)
4310 {
4311         int fd, res;
4312         struct strbuf nbuf = STRBUF_INIT;
4313
4314         if (S_ISGITLINK(mode)) {
4315                 struct stat st;
4316                 if (!lstat(path, &st) && S_ISDIR(st.st_mode))
4317                         return 0;
4318                 return !!mkdir(path, 0777);
4319         }
4320
4321         if (has_symlinks && S_ISLNK(mode))
4322                 /* Although buf:size is counted string, it also is NUL
4323                  * terminated.
4324                  */
4325                 return !!symlink(buf, path);
4326
4327         fd = open(path, O_CREAT | O_EXCL | O_WRONLY, (mode & 0100) ? 0777 : 0666);
4328         if (fd < 0)
4329                 return 1;
4330
4331         if (convert_to_working_tree(path, buf, size, &nbuf)) {
4332                 size = nbuf.len;
4333                 buf  = nbuf.buf;
4334         }
4335
4336         res = write_in_full(fd, buf, size) < 0;
4337         if (res)
4338                 error_errno(_("failed to write to '%s'"), path);
4339         strbuf_release(&nbuf);
4340
4341         if (close(fd) < 0 && !res)
4342                 return error_errno(_("closing file '%s'"), path);
4343
4344         return res ? -1 : 0;
4345 }
4346
4347 /*
4348  * We optimistically assume that the directories exist,
4349  * which is true 99% of the time anyway. If they don't,
4350  * we create them and try again.
4351  *
4352  * Returns:
4353  *   -1 on error
4354  *   0 otherwise
4355  */
4356 static int create_one_file(struct apply_state *state,
4357                            char *path,
4358                            unsigned mode,
4359                            const char *buf,
4360                            unsigned long size)
4361 {
4362         int res;
4363
4364         if (state->cached)
4365                 return 0;
4366
4367         res = try_create_file(path, mode, buf, size);
4368         if (res < 0)
4369                 return -1;
4370         if (!res)
4371                 return 0;
4372
4373         if (errno == ENOENT) {
4374                 if (safe_create_leading_directories(path))
4375                         return 0;
4376                 res = try_create_file(path, mode, buf, size);
4377                 if (res < 0)
4378                         return -1;
4379                 if (!res)
4380                         return 0;
4381         }
4382
4383         if (errno == EEXIST || errno == EACCES) {
4384                 /* We may be trying to create a file where a directory
4385                  * used to be.
4386                  */
4387                 struct stat st;
4388                 if (!lstat(path, &st) && (!S_ISDIR(st.st_mode) || !rmdir(path)))
4389                         errno = EEXIST;
4390         }
4391
4392         if (errno == EEXIST) {
4393                 unsigned int nr = getpid();
4394
4395                 for (;;) {
4396                         char newpath[PATH_MAX];
4397                         mksnpath(newpath, sizeof(newpath), "%s~%u", path, nr);
4398                         res = try_create_file(newpath, mode, buf, size);
4399                         if (res < 0)
4400                                 return -1;
4401                         if (!res) {
4402                                 if (!rename(newpath, path))
4403                                         return 0;
4404                                 unlink_or_warn(newpath);
4405                                 break;
4406                         }
4407                         if (errno != EEXIST)
4408                                 break;
4409                         ++nr;
4410                 }
4411         }
4412         return error_errno(_("unable to write file '%s' mode %o"),
4413                            path, mode);
4414 }
4415
4416 static int add_conflicted_stages_file(struct apply_state *state,
4417                                        struct patch *patch)
4418 {
4419         int stage, namelen;
4420         unsigned ce_size, mode;
4421         struct cache_entry *ce;
4422
4423         if (!state->update_index)
4424                 return 0;
4425         namelen = strlen(patch->new_name);
4426         ce_size = cache_entry_size(namelen);
4427         mode = patch->new_mode ? patch->new_mode : (S_IFREG | 0644);
4428
4429         remove_file_from_cache(patch->new_name);
4430         for (stage = 1; stage < 4; stage++) {
4431                 if (is_null_oid(&patch->threeway_stage[stage - 1]))
4432                         continue;
4433                 ce = xcalloc(1, ce_size);
4434                 memcpy(ce->name, patch->new_name, namelen);
4435                 ce->ce_mode = create_ce_mode(mode);
4436                 ce->ce_flags = create_ce_flags(stage);
4437                 ce->ce_namelen = namelen;
4438                 oidcpy(&ce->oid, &patch->threeway_stage[stage - 1]);
4439                 if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD) < 0) {
4440                         free(ce);
4441                         return error(_("unable to add cache entry for %s"),
4442                                      patch->new_name);
4443                 }
4444         }
4445
4446         return 0;
4447 }
4448
4449 static int create_file(struct apply_state *state, struct patch *patch)
4450 {
4451         char *path = patch->new_name;
4452         unsigned mode = patch->new_mode;
4453         unsigned long size = patch->resultsize;
4454         char *buf = patch->result;
4455
4456         if (!mode)
4457                 mode = S_IFREG | 0644;
4458         if (create_one_file(state, path, mode, buf, size))
4459                 return -1;
4460
4461         if (patch->conflicted_threeway)
4462                 return add_conflicted_stages_file(state, patch);
4463         else
4464                 return add_index_file(state, path, mode, buf, size);
4465 }
4466
4467 /* phase zero is to remove, phase one is to create */
4468 static int write_out_one_result(struct apply_state *state,
4469                                 struct patch *patch,
4470                                 int phase)
4471 {
4472         if (patch->is_delete > 0) {
4473                 if (phase == 0)
4474                         return remove_file(state, patch, 1);
4475                 return 0;
4476         }
4477         if (patch->is_new > 0 || patch->is_copy) {
4478                 if (phase == 1)
4479                         return create_file(state, patch);
4480                 return 0;
4481         }
4482         /*
4483          * Rename or modification boils down to the same
4484          * thing: remove the old, write the new
4485          */
4486         if (phase == 0)
4487                 return remove_file(state, patch, patch->is_rename);
4488         if (phase == 1)
4489                 return create_file(state, patch);
4490         return 0;
4491 }
4492
4493 static int write_out_one_reject(struct apply_state *state, struct patch *patch)
4494 {
4495         FILE *rej;
4496         char namebuf[PATH_MAX];
4497         struct fragment *frag;
4498         int cnt = 0;
4499         struct strbuf sb = STRBUF_INIT;
4500
4501         for (cnt = 0, frag = patch->fragments; frag; frag = frag->next) {
4502                 if (!frag->rejected)
4503                         continue;
4504                 cnt++;
4505         }
4506
4507         if (!cnt) {
4508                 if (state->apply_verbosity > verbosity_normal)
4509                         say_patch_name(stderr,
4510                                        _("Applied patch %s cleanly."), patch);
4511                 return 0;
4512         }
4513
4514         /* This should not happen, because a removal patch that leaves
4515          * contents are marked "rejected" at the patch level.
4516          */
4517         if (!patch->new_name)
4518                 die(_("internal error"));
4519
4520         /* Say this even without --verbose */
4521         strbuf_addf(&sb, Q_("Applying patch %%s with %d reject...",
4522                             "Applying patch %%s with %d rejects...",
4523                             cnt),
4524                     cnt);
4525         if (state->apply_verbosity > verbosity_silent)
4526                 say_patch_name(stderr, sb.buf, patch);
4527         strbuf_release(&sb);
4528
4529         cnt = strlen(patch->new_name);
4530         if (ARRAY_SIZE(namebuf) <= cnt + 5) {
4531                 cnt = ARRAY_SIZE(namebuf) - 5;
4532                 warning(_("truncating .rej filename to %.*s.rej"),
4533                         cnt - 1, patch->new_name);
4534         }
4535         memcpy(namebuf, patch->new_name, cnt);
4536         memcpy(namebuf + cnt, ".rej", 5);
4537
4538         rej = fopen(namebuf, "w");
4539         if (!rej)
4540                 return error_errno(_("cannot open %s"), namebuf);
4541
4542         /* Normal git tools never deal with .rej, so do not pretend
4543          * this is a git patch by saying --git or giving extended
4544          * headers.  While at it, maybe please "kompare" that wants
4545          * the trailing TAB and some garbage at the end of line ;-).
4546          */
4547         fprintf(rej, "diff a/%s b/%s\t(rejected hunks)\n",
4548                 patch->new_name, patch->new_name);
4549         for (cnt = 1, frag = patch->fragments;
4550              frag;
4551              cnt++, frag = frag->next) {
4552                 if (!frag->rejected) {
4553                         if (state->apply_verbosity > verbosity_silent)
4554                                 fprintf_ln(stderr, _("Hunk #%d applied cleanly."), cnt);
4555                         continue;
4556                 }
4557                 if (state->apply_verbosity > verbosity_silent)
4558                         fprintf_ln(stderr, _("Rejected hunk #%d."), cnt);
4559                 fprintf(rej, "%.*s", frag->size, frag->patch);
4560                 if (frag->patch[frag->size-1] != '\n')
4561                         fputc('\n', rej);
4562         }
4563         fclose(rej);
4564         return -1;
4565 }
4566
4567 /*
4568  * Returns:
4569  *  -1 if an error happened
4570  *   0 if the patch applied cleanly
4571  *   1 if the patch did not apply cleanly
4572  */
4573 static int write_out_results(struct apply_state *state, struct patch *list)
4574 {
4575         int phase;
4576         int errs = 0;
4577         struct patch *l;
4578         struct string_list cpath = STRING_LIST_INIT_DUP;
4579
4580         for (phase = 0; phase < 2; phase++) {
4581                 l = list;
4582                 while (l) {
4583                         if (l->rejected)
4584                                 errs = 1;
4585                         else {
4586                                 if (write_out_one_result(state, l, phase)) {
4587                                         string_list_clear(&cpath, 0);
4588                                         return -1;
4589                                 }
4590                                 if (phase == 1) {
4591                                         if (write_out_one_reject(state, l))
4592                                                 errs = 1;
4593                                         if (l->conflicted_threeway) {
4594                                                 string_list_append(&cpath, l->new_name);
4595                                                 errs = 1;
4596                                         }
4597                                 }
4598                         }
4599                         l = l->next;
4600                 }
4601         }
4602
4603         if (cpath.nr) {
4604                 struct string_list_item *item;
4605
4606                 string_list_sort(&cpath);
4607                 if (state->apply_verbosity > verbosity_silent) {
4608                         for_each_string_list_item(item, &cpath)
4609                                 fprintf(stderr, "U %s\n", item->string);
4610                 }
4611                 string_list_clear(&cpath, 0);
4612
4613                 rerere(0);
4614         }
4615
4616         return errs;
4617 }
4618
4619 /*
4620  * Try to apply a patch.
4621  *
4622  * Returns:
4623  *  -128 if a bad error happened (like patch unreadable)
4624  *  -1 if patch did not apply and user cannot deal with it
4625  *   0 if the patch applied
4626  *   1 if the patch did not apply but user might fix it
4627  */
4628 static int apply_patch(struct apply_state *state,
4629                        int fd,
4630                        const char *filename,
4631                        int options)
4632 {
4633         size_t offset;
4634         struct strbuf buf = STRBUF_INIT; /* owns the patch text */
4635         struct patch *list = NULL, **listp = &list;
4636         int skipped_patch = 0;
4637         int res = 0;
4638
4639         state->patch_input_file = filename;
4640         if (read_patch_file(&buf, fd) < 0)
4641                 return -128;
4642         offset = 0;
4643         while (offset < buf.len) {
4644                 struct patch *patch;
4645                 int nr;
4646
4647                 patch = xcalloc(1, sizeof(*patch));
4648                 patch->inaccurate_eof = !!(options & APPLY_OPT_INACCURATE_EOF);
4649                 patch->recount =  !!(options & APPLY_OPT_RECOUNT);
4650                 nr = parse_chunk(state, buf.buf + offset, buf.len - offset, patch);
4651                 if (nr < 0) {
4652                         free_patch(patch);
4653                         if (nr == -128) {
4654                                 res = -128;
4655                                 goto end;
4656                         }
4657                         break;
4658                 }
4659                 if (state->apply_in_reverse)
4660                         reverse_patches(patch);
4661                 if (use_patch(state, patch)) {
4662                         patch_stats(state, patch);
4663                         *listp = patch;
4664                         listp = &patch->next;
4665                 }
4666                 else {
4667                         if (state->apply_verbosity > verbosity_normal)
4668                                 say_patch_name(stderr, _("Skipped patch '%s'."), patch);
4669                         free_patch(patch);
4670                         skipped_patch++;
4671                 }
4672                 offset += nr;
4673         }
4674
4675         if (!list && !skipped_patch) {
4676                 error(_("unrecognized input"));
4677                 res = -128;
4678                 goto end;
4679         }
4680
4681         if (state->whitespace_error && (state->ws_error_action == die_on_ws_error))
4682                 state->apply = 0;
4683
4684         state->update_index = state->check_index && state->apply;
4685         if (state->update_index && state->newfd < 0) {
4686                 if (state->index_file)
4687                         state->newfd = hold_lock_file_for_update(state->lock_file,
4688                                                                  state->index_file,
4689                                                                  LOCK_DIE_ON_ERROR);
4690                 else
4691                         state->newfd = hold_locked_index(state->lock_file, LOCK_DIE_ON_ERROR);
4692         }
4693
4694         if (state->check_index && read_apply_cache(state) < 0) {
4695                 error(_("unable to read index file"));
4696                 res = -128;
4697                 goto end;
4698         }
4699
4700         if (state->check || state->apply) {
4701                 int r = check_patch_list(state, list);
4702                 if (r == -128) {
4703                         res = -128;
4704                         goto end;
4705                 }
4706                 if (r < 0 && !state->apply_with_reject) {
4707                         res = -1;
4708                         goto end;
4709                 }
4710         }
4711
4712         if (state->apply) {
4713                 int write_res = write_out_results(state, list);
4714                 if (write_res < 0) {
4715                         res = -128;
4716                         goto end;
4717                 }
4718                 if (write_res > 0) {
4719                         /* with --3way, we still need to write the index out */
4720                         res = state->apply_with_reject ? -1 : 1;
4721                         goto end;
4722                 }
4723         }
4724
4725         if (state->fake_ancestor &&
4726             build_fake_ancestor(state, list)) {
4727                 res = -128;
4728                 goto end;
4729         }
4730
4731         if (state->diffstat && state->apply_verbosity > verbosity_silent)
4732                 stat_patch_list(state, list);
4733
4734         if (state->numstat && state->apply_verbosity > verbosity_silent)
4735                 numstat_patch_list(state, list);
4736
4737         if (state->summary && state->apply_verbosity > verbosity_silent)
4738                 summary_patch_list(list);
4739
4740 end:
4741         free_patch_list(list);
4742         strbuf_release(&buf);
4743         string_list_clear(&state->fn_table, 0);
4744         return res;
4745 }
4746
4747 static int apply_option_parse_exclude(const struct option *opt,
4748                                       const char *arg, int unset)
4749 {
4750         struct apply_state *state = opt->value;
4751         add_name_limit(state, arg, 1);
4752         return 0;
4753 }
4754
4755 static int apply_option_parse_include(const struct option *opt,
4756                                       const char *arg, int unset)
4757 {
4758         struct apply_state *state = opt->value;
4759         add_name_limit(state, arg, 0);
4760         state->has_include = 1;
4761         return 0;
4762 }
4763
4764 static int apply_option_parse_p(const struct option *opt,
4765                                 const char *arg,
4766                                 int unset)
4767 {
4768         struct apply_state *state = opt->value;
4769         state->p_value = atoi(arg);
4770         state->p_value_known = 1;
4771         return 0;
4772 }
4773
4774 static int apply_option_parse_space_change(const struct option *opt,
4775                                            const char *arg, int unset)
4776 {
4777         struct apply_state *state = opt->value;
4778         if (unset)
4779                 state->ws_ignore_action = ignore_ws_none;
4780         else
4781                 state->ws_ignore_action = ignore_ws_change;
4782         return 0;
4783 }
4784
4785 static int apply_option_parse_whitespace(const struct option *opt,
4786                                          const char *arg, int unset)
4787 {
4788         struct apply_state *state = opt->value;
4789         state->whitespace_option = arg;
4790         if (parse_whitespace_option(state, arg))
4791                 exit(1);
4792         return 0;
4793 }
4794
4795 static int apply_option_parse_directory(const struct option *opt,
4796                                         const char *arg, int unset)
4797 {
4798         struct apply_state *state = opt->value;
4799         strbuf_reset(&state->root);
4800         strbuf_addstr(&state->root, arg);
4801         strbuf_complete(&state->root, '/');
4802         return 0;
4803 }
4804
4805 int apply_all_patches(struct apply_state *state,
4806                       int argc,
4807                       const char **argv,
4808                       int options)
4809 {
4810         int i;
4811         int res;
4812         int errs = 0;
4813         int read_stdin = 1;
4814
4815         for (i = 0; i < argc; i++) {
4816                 const char *arg = argv[i];
4817                 int fd;
4818
4819                 if (!strcmp(arg, "-")) {
4820                         res = apply_patch(state, 0, "<stdin>", options);
4821                         if (res < 0)
4822                                 goto end;
4823                         errs |= res;
4824                         read_stdin = 0;
4825                         continue;
4826                 } else if (0 < state->prefix_length)
4827                         arg = prefix_filename(state->prefix,
4828                                               state->prefix_length,
4829                                               arg);
4830
4831                 fd = open(arg, O_RDONLY);
4832                 if (fd < 0) {
4833                         error(_("can't open patch '%s': %s"), arg, strerror(errno));
4834                         res = -128;
4835                         goto end;
4836                 }
4837                 read_stdin = 0;
4838                 set_default_whitespace_mode(state);
4839                 res = apply_patch(state, fd, arg, options);
4840                 close(fd);
4841                 if (res < 0)
4842                         goto end;
4843                 errs |= res;
4844         }
4845         set_default_whitespace_mode(state);
4846         if (read_stdin) {
4847                 res = apply_patch(state, 0, "<stdin>", options);
4848                 if (res < 0)
4849                         goto end;
4850                 errs |= res;
4851         }
4852
4853         if (state->whitespace_error) {
4854                 if (state->squelch_whitespace_errors &&
4855                     state->squelch_whitespace_errors < state->whitespace_error) {
4856                         int squelched =
4857                                 state->whitespace_error - state->squelch_whitespace_errors;
4858                         warning(Q_("squelched %d whitespace error",
4859                                    "squelched %d whitespace errors",
4860                                    squelched),
4861                                 squelched);
4862                 }
4863                 if (state->ws_error_action == die_on_ws_error) {
4864                         error(Q_("%d line adds whitespace errors.",
4865                                  "%d lines add whitespace errors.",
4866                                  state->whitespace_error),
4867                               state->whitespace_error);
4868                         res = -128;
4869                         goto end;
4870                 }
4871                 if (state->applied_after_fixing_ws && state->apply)
4872                         warning(Q_("%d line applied after"
4873                                    " fixing whitespace errors.",
4874                                    "%d lines applied after"
4875                                    " fixing whitespace errors.",
4876                                    state->applied_after_fixing_ws),
4877                                 state->applied_after_fixing_ws);
4878                 else if (state->whitespace_error)
4879                         warning(Q_("%d line adds whitespace errors.",
4880                                    "%d lines add whitespace errors.",
4881                                    state->whitespace_error),
4882                                 state->whitespace_error);
4883         }
4884
4885         if (state->update_index) {
4886                 res = write_locked_index(&the_index, state->lock_file, COMMIT_LOCK);
4887                 if (res) {
4888                         error(_("Unable to write new index file"));
4889                         res = -128;
4890                         goto end;
4891                 }
4892                 state->newfd = -1;
4893         }
4894
4895         res = !!errs;
4896
4897 end:
4898         if (state->newfd >= 0) {
4899                 rollback_lock_file(state->lock_file);
4900                 state->newfd = -1;
4901         }
4902
4903         if (state->apply_verbosity <= verbosity_silent) {
4904                 set_error_routine(state->saved_error_routine);
4905                 set_warn_routine(state->saved_warn_routine);
4906         }
4907
4908         if (res > -1)
4909                 return res;
4910         return (res == -1 ? 1 : 128);
4911 }
4912
4913 int apply_parse_options(int argc, const char **argv,
4914                         struct apply_state *state,
4915                         int *force_apply, int *options,
4916                         const char * const *apply_usage)
4917 {
4918         struct option builtin_apply_options[] = {
4919                 { OPTION_CALLBACK, 0, "exclude", state, N_("path"),
4920                         N_("don't apply changes matching the given path"),
4921                         0, apply_option_parse_exclude },
4922                 { OPTION_CALLBACK, 0, "include", state, N_("path"),
4923                         N_("apply changes matching the given path"),
4924                         0, apply_option_parse_include },
4925                 { OPTION_CALLBACK, 'p', NULL, state, N_("num"),
4926                         N_("remove <num> leading slashes from traditional diff paths"),
4927                         0, apply_option_parse_p },
4928                 OPT_BOOL(0, "no-add", &state->no_add,
4929                         N_("ignore additions made by the patch")),
4930                 OPT_BOOL(0, "stat", &state->diffstat,
4931                         N_("instead of applying the patch, output diffstat for the input")),
4932                 OPT_NOOP_NOARG(0, "allow-binary-replacement"),
4933                 OPT_NOOP_NOARG(0, "binary"),
4934                 OPT_BOOL(0, "numstat", &state->numstat,
4935                         N_("show number of added and deleted lines in decimal notation")),
4936                 OPT_BOOL(0, "summary", &state->summary,
4937                         N_("instead of applying the patch, output a summary for the input")),
4938                 OPT_BOOL(0, "check", &state->check,
4939                         N_("instead of applying the patch, see if the patch is applicable")),
4940                 OPT_BOOL(0, "index", &state->check_index,
4941                         N_("make sure the patch is applicable to the current index")),
4942                 OPT_BOOL(0, "cached", &state->cached,
4943                         N_("apply a patch without touching the working tree")),
4944                 OPT_BOOL(0, "unsafe-paths", &state->unsafe_paths,
4945                         N_("accept a patch that touches outside the working area")),
4946                 OPT_BOOL(0, "apply", force_apply,
4947                         N_("also apply the patch (use with --stat/--summary/--check)")),
4948                 OPT_BOOL('3', "3way", &state->threeway,
4949                          N_( "attempt three-way merge if a patch does not apply")),
4950                 OPT_FILENAME(0, "build-fake-ancestor", &state->fake_ancestor,
4951                         N_("build a temporary index based on embedded index information")),
4952                 /* Think twice before adding "--nul" synonym to this */
4953                 OPT_SET_INT('z', NULL, &state->line_termination,
4954                         N_("paths are separated with NUL character"), '\0'),
4955                 OPT_INTEGER('C', NULL, &state->p_context,
4956                                 N_("ensure at least <n> lines of context match")),
4957                 { OPTION_CALLBACK, 0, "whitespace", state, N_("action"),
4958                         N_("detect new or modified lines that have whitespace errors"),
4959                         0, apply_option_parse_whitespace },
4960                 { OPTION_CALLBACK, 0, "ignore-space-change", state, NULL,
4961                         N_("ignore changes in whitespace when finding context"),
4962                         PARSE_OPT_NOARG, apply_option_parse_space_change },
4963                 { OPTION_CALLBACK, 0, "ignore-whitespace", state, NULL,
4964                         N_("ignore changes in whitespace when finding context"),
4965                         PARSE_OPT_NOARG, apply_option_parse_space_change },
4966                 OPT_BOOL('R', "reverse", &state->apply_in_reverse,
4967                         N_("apply the patch in reverse")),
4968                 OPT_BOOL(0, "unidiff-zero", &state->unidiff_zero,
4969                         N_("don't expect at least one line of context")),
4970                 OPT_BOOL(0, "reject", &state->apply_with_reject,
4971                         N_("leave the rejected hunks in corresponding *.rej files")),
4972                 OPT_BOOL(0, "allow-overlap", &state->allow_overlap,
4973                         N_("allow overlapping hunks")),
4974                 OPT__VERBOSE(&state->apply_verbosity, N_("be verbose")),
4975                 OPT_BIT(0, "inaccurate-eof", options,
4976                         N_("tolerate incorrectly detected missing new-line at the end of file"),
4977                         APPLY_OPT_INACCURATE_EOF),
4978                 OPT_BIT(0, "recount", options,
4979                         N_("do not trust the line counts in the hunk headers"),
4980                         APPLY_OPT_RECOUNT),
4981                 { OPTION_CALLBACK, 0, "directory", state, N_("root"),
4982                         N_("prepend <root> to all filenames"),
4983                         0, apply_option_parse_directory },
4984                 OPT_END()
4985         };
4986
4987         return parse_options(argc, argv, state->prefix, builtin_apply_options, apply_usage, 0);
4988 }