Merge branch 'rk/completion-stash'
[git] / add-patch.c
1 #include "cache.h"
2 #include "add-interactive.h"
3 #include "strbuf.h"
4 #include "run-command.h"
5 #include "strvec.h"
6 #include "pathspec.h"
7 #include "color.h"
8 #include "diff.h"
9 #include "compat/terminal.h"
10 #include "prompt.h"
11
12 enum prompt_mode_type {
13         PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_ADDITION, PROMPT_HUNK,
14         PROMPT_MODE_MAX, /* must be last */
15 };
16
17 struct patch_mode {
18         /*
19          * The magic constant 4 is chosen such that all patch modes
20          * provide enough space for three command-line arguments followed by a
21          * trailing `NULL`.
22          */
23         const char *diff_cmd[4], *apply_args[4], *apply_check_args[4];
24         unsigned is_reverse:1, index_only:1, apply_for_checkout:1;
25         const char *prompt_mode[PROMPT_MODE_MAX];
26         const char *edit_hunk_hint, *help_patch_text;
27 };
28
29 static struct patch_mode patch_mode_add = {
30         .diff_cmd = { "diff-files", NULL },
31         .apply_args = { "--cached", NULL },
32         .apply_check_args = { "--cached", NULL },
33         .prompt_mode = {
34                 N_("Stage mode change [y,n,q,a,d%s,?]? "),
35                 N_("Stage deletion [y,n,q,a,d%s,?]? "),
36                 N_("Stage addition [y,n,q,a,d%s,?]? "),
37                 N_("Stage this hunk [y,n,q,a,d%s,?]? ")
38         },
39         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
40                              "will immediately be marked for staging."),
41         .help_patch_text =
42                 N_("y - stage this hunk\n"
43                    "n - do not stage this hunk\n"
44                    "q - quit; do not stage this hunk or any of the remaining "
45                         "ones\n"
46                    "a - stage this hunk and all later hunks in the file\n"
47                    "d - do not stage this hunk or any of the later hunks in "
48                         "the file\n")
49 };
50
51 static struct patch_mode patch_mode_stash = {
52         .diff_cmd = { "diff-index", "HEAD", NULL },
53         .apply_args = { "--cached", NULL },
54         .apply_check_args = { "--cached", NULL },
55         .prompt_mode = {
56                 N_("Stash mode change [y,n,q,a,d%s,?]? "),
57                 N_("Stash deletion [y,n,q,a,d%s,?]? "),
58                 N_("Stash addition [y,n,q,a,d%s,?]? "),
59                 N_("Stash this hunk [y,n,q,a,d%s,?]? "),
60         },
61         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
62                              "will immediately be marked for stashing."),
63         .help_patch_text =
64                 N_("y - stash this hunk\n"
65                    "n - do not stash this hunk\n"
66                    "q - quit; do not stash this hunk or any of the remaining "
67                         "ones\n"
68                    "a - stash this hunk and all later hunks in the file\n"
69                    "d - do not stash this hunk or any of the later hunks in "
70                         "the file\n"),
71 };
72
73 static struct patch_mode patch_mode_reset_head = {
74         .diff_cmd = { "diff-index", "--cached", NULL },
75         .apply_args = { "-R", "--cached", NULL },
76         .apply_check_args = { "-R", "--cached", NULL },
77         .is_reverse = 1,
78         .index_only = 1,
79         .prompt_mode = {
80                 N_("Unstage mode change [y,n,q,a,d%s,?]? "),
81                 N_("Unstage deletion [y,n,q,a,d%s,?]? "),
82                 N_("Unstage addition [y,n,q,a,d%s,?]? "),
83                 N_("Unstage this hunk [y,n,q,a,d%s,?]? "),
84         },
85         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
86                              "will immediately be marked for unstaging."),
87         .help_patch_text =
88                 N_("y - unstage this hunk\n"
89                    "n - do not unstage this hunk\n"
90                    "q - quit; do not unstage this hunk or any of the remaining "
91                         "ones\n"
92                    "a - unstage this hunk and all later hunks in the file\n"
93                    "d - do not unstage this hunk or any of the later hunks in "
94                         "the file\n"),
95 };
96
97 static struct patch_mode patch_mode_reset_nothead = {
98         .diff_cmd = { "diff-index", "-R", "--cached", NULL },
99         .apply_args = { "--cached", NULL },
100         .apply_check_args = { "--cached", NULL },
101         .index_only = 1,
102         .prompt_mode = {
103                 N_("Apply mode change to index [y,n,q,a,d%s,?]? "),
104                 N_("Apply deletion to index [y,n,q,a,d%s,?]? "),
105                 N_("Apply addition to index [y,n,q,a,d%s,?]? "),
106                 N_("Apply this hunk to index [y,n,q,a,d%s,?]? "),
107         },
108         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
109                              "will immediately be marked for applying."),
110         .help_patch_text =
111                 N_("y - apply this hunk to index\n"
112                    "n - do not apply this hunk to index\n"
113                    "q - quit; do not apply this hunk or any of the remaining "
114                         "ones\n"
115                    "a - apply this hunk and all later hunks in the file\n"
116                    "d - do not apply this hunk or any of the later hunks in "
117                         "the file\n"),
118 };
119
120 static struct patch_mode patch_mode_checkout_index = {
121         .diff_cmd = { "diff-files", NULL },
122         .apply_args = { "-R", NULL },
123         .apply_check_args = { "-R", NULL },
124         .is_reverse = 1,
125         .prompt_mode = {
126                 N_("Discard mode change from worktree [y,n,q,a,d%s,?]? "),
127                 N_("Discard deletion from worktree [y,n,q,a,d%s,?]? "),
128                 N_("Discard addition from worktree [y,n,q,a,d%s,?]? "),
129                 N_("Discard this hunk from worktree [y,n,q,a,d%s,?]? "),
130         },
131         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
132                              "will immediately be marked for discarding."),
133         .help_patch_text =
134                 N_("y - discard this hunk from worktree\n"
135                    "n - do not discard this hunk from worktree\n"
136                    "q - quit; do not discard this hunk or any of the remaining "
137                         "ones\n"
138                    "a - discard this hunk and all later hunks in the file\n"
139                    "d - do not discard this hunk or any of the later hunks in "
140                         "the file\n"),
141 };
142
143 static struct patch_mode patch_mode_checkout_head = {
144         .diff_cmd = { "diff-index", NULL },
145         .apply_for_checkout = 1,
146         .apply_check_args = { "-R", NULL },
147         .is_reverse = 1,
148         .prompt_mode = {
149                 N_("Discard mode change from index and worktree [y,n,q,a,d%s,?]? "),
150                 N_("Discard deletion from index and worktree [y,n,q,a,d%s,?]? "),
151                 N_("Discard addition from index and worktree [y,n,q,a,d%s,?]? "),
152                 N_("Discard this hunk from index and worktree [y,n,q,a,d%s,?]? "),
153         },
154         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
155                              "will immediately be marked for discarding."),
156         .help_patch_text =
157                 N_("y - discard this hunk from index and worktree\n"
158                    "n - do not discard this hunk from index and worktree\n"
159                    "q - quit; do not discard this hunk or any of the remaining "
160                         "ones\n"
161                    "a - discard this hunk and all later hunks in the file\n"
162                    "d - do not discard this hunk or any of the later hunks in "
163                         "the file\n"),
164 };
165
166 static struct patch_mode patch_mode_checkout_nothead = {
167         .diff_cmd = { "diff-index", "-R", NULL },
168         .apply_for_checkout = 1,
169         .apply_check_args = { NULL },
170         .prompt_mode = {
171                 N_("Apply mode change to index and worktree [y,n,q,a,d%s,?]? "),
172                 N_("Apply deletion to index and worktree [y,n,q,a,d%s,?]? "),
173                 N_("Apply addition to index and worktree [y,n,q,a,d%s,?]? "),
174                 N_("Apply this hunk to index and worktree [y,n,q,a,d%s,?]? "),
175         },
176         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
177                              "will immediately be marked for applying."),
178         .help_patch_text =
179                 N_("y - apply this hunk to index and worktree\n"
180                    "n - do not apply this hunk to index and worktree\n"
181                    "q - quit; do not apply this hunk or any of the remaining "
182                         "ones\n"
183                    "a - apply this hunk and all later hunks in the file\n"
184                    "d - do not apply this hunk or any of the later hunks in "
185                         "the file\n"),
186 };
187
188 static struct patch_mode patch_mode_worktree_head = {
189         .diff_cmd = { "diff-index", NULL },
190         .apply_args = { "-R", NULL },
191         .apply_check_args = { "-R", NULL },
192         .is_reverse = 1,
193         .prompt_mode = {
194                 N_("Discard mode change from index and worktree [y,n,q,a,d%s,?]? "),
195                 N_("Discard deletion from index and worktree [y,n,q,a,d%s,?]? "),
196                 N_("Discard addition from index and worktree [y,n,q,a,d%s,?]? "),
197                 N_("Discard this hunk from index and worktree [y,n,q,a,d%s,?]? "),
198         },
199         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
200                              "will immediately be marked for discarding."),
201         .help_patch_text =
202                 N_("y - discard this hunk from worktree\n"
203                    "n - do not discard this hunk from worktree\n"
204                    "q - quit; do not discard this hunk or any of the remaining "
205                         "ones\n"
206                    "a - discard this hunk and all later hunks in the file\n"
207                    "d - do not discard this hunk or any of the later hunks in "
208                         "the file\n"),
209 };
210
211 static struct patch_mode patch_mode_worktree_nothead = {
212         .diff_cmd = { "diff-index", "-R", NULL },
213         .apply_args = { NULL },
214         .apply_check_args = { NULL },
215         .prompt_mode = {
216                 N_("Apply mode change to index and worktree [y,n,q,a,d%s,?]? "),
217                 N_("Apply deletion to index and worktree [y,n,q,a,d%s,?]? "),
218                 N_("Apply addition to index and worktree [y,n,q,a,d%s,?]? "),
219                 N_("Apply this hunk to index and worktree [y,n,q,a,d%s,?]? "),
220         },
221         .edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
222                              "will immediately be marked for applying."),
223         .help_patch_text =
224                 N_("y - apply this hunk to worktree\n"
225                    "n - do not apply this hunk to worktree\n"
226                    "q - quit; do not apply this hunk or any of the remaining "
227                         "ones\n"
228                    "a - apply this hunk and all later hunks in the file\n"
229                    "d - do not apply this hunk or any of the later hunks in "
230                         "the file\n"),
231 };
232
233 struct hunk_header {
234         unsigned long old_offset, old_count, new_offset, new_count;
235         /*
236          * Start/end offsets to the extra text after the second `@@` in the
237          * hunk header, e.g. the function signature. This is expected to
238          * include the newline.
239          */
240         size_t extra_start, extra_end, colored_extra_start, colored_extra_end;
241 };
242
243 struct hunk {
244         size_t start, end, colored_start, colored_end, splittable_into;
245         ssize_t delta;
246         enum { UNDECIDED_HUNK = 0, SKIP_HUNK, USE_HUNK } use;
247         struct hunk_header header;
248 };
249
250 struct add_p_state {
251         struct add_i_state s;
252         struct strbuf answer, buf;
253
254         /* parsed diff */
255         struct strbuf plain, colored;
256         struct file_diff {
257                 struct hunk head;
258                 struct hunk *hunk;
259                 size_t hunk_nr, hunk_alloc;
260                 unsigned deleted:1, added:1, mode_change:1,binary:1;
261         } *file_diff;
262         size_t file_diff_nr;
263
264         /* patch mode */
265         struct patch_mode *mode;
266         const char *revision;
267 };
268
269 static void add_p_state_clear(struct add_p_state *s)
270 {
271         size_t i;
272
273         strbuf_release(&s->answer);
274         strbuf_release(&s->buf);
275         strbuf_release(&s->plain);
276         strbuf_release(&s->colored);
277         for (i = 0; i < s->file_diff_nr; i++)
278                 free(s->file_diff[i].hunk);
279         free(s->file_diff);
280         clear_add_i_state(&s->s);
281 }
282
283 static void err(struct add_p_state *s, const char *fmt, ...)
284 {
285         va_list args;
286
287         va_start(args, fmt);
288         fputs(s->s.error_color, stderr);
289         vfprintf(stderr, fmt, args);
290         fputs(s->s.reset_color, stderr);
291         fputc('\n', stderr);
292         va_end(args);
293 }
294
295 static void setup_child_process(struct add_p_state *s,
296                                 struct child_process *cp, ...)
297 {
298         va_list ap;
299         const char *arg;
300
301         va_start(ap, cp);
302         while ((arg = va_arg(ap, const char *)))
303                 strvec_push(&cp->args, arg);
304         va_end(ap);
305
306         cp->git_cmd = 1;
307         strvec_pushf(&cp->env_array,
308                      INDEX_ENVIRONMENT "=%s", s->s.r->index_file);
309 }
310
311 static int parse_range(const char **p,
312                        unsigned long *offset, unsigned long *count)
313 {
314         char *pend;
315
316         *offset = strtoul(*p, &pend, 10);
317         if (pend == *p)
318                 return -1;
319         if (*pend != ',') {
320                 *count = 1;
321                 *p = pend;
322                 return 0;
323         }
324         *count = strtoul(pend + 1, (char **)p, 10);
325         return *p == pend + 1 ? -1 : 0;
326 }
327
328 static int parse_hunk_header(struct add_p_state *s, struct hunk *hunk)
329 {
330         struct hunk_header *header = &hunk->header;
331         const char *line = s->plain.buf + hunk->start, *p = line;
332         char *eol = memchr(p, '\n', s->plain.len - hunk->start);
333
334         if (!eol)
335                 eol = s->plain.buf + s->plain.len;
336
337         if (!skip_prefix(p, "@@ -", &p) ||
338             parse_range(&p, &header->old_offset, &header->old_count) < 0 ||
339             !skip_prefix(p, " +", &p) ||
340             parse_range(&p, &header->new_offset, &header->new_count) < 0 ||
341             !skip_prefix(p, " @@", &p))
342                 return error(_("could not parse hunk header '%.*s'"),
343                              (int)(eol - line), line);
344
345         hunk->start = eol - s->plain.buf + (*eol == '\n');
346         header->extra_start = p - s->plain.buf;
347         header->extra_end = hunk->start;
348
349         if (!s->colored.len) {
350                 header->colored_extra_start = header->colored_extra_end = 0;
351                 return 0;
352         }
353
354         /* Now find the extra text in the colored diff */
355         line = s->colored.buf + hunk->colored_start;
356         eol = memchr(line, '\n', s->colored.len - hunk->colored_start);
357         if (!eol)
358                 eol = s->colored.buf + s->colored.len;
359         p = memmem(line, eol - line, "@@ -", 4);
360         if (!p)
361                 return error(_("could not parse colored hunk header '%.*s'"),
362                              (int)(eol - line), line);
363         p = memmem(p + 4, eol - p - 4, " @@", 3);
364         if (!p)
365                 return error(_("could not parse colored hunk header '%.*s'"),
366                              (int)(eol - line), line);
367         hunk->colored_start = eol - s->colored.buf + (*eol == '\n');
368         header->colored_extra_start = p + 3 - s->colored.buf;
369         header->colored_extra_end = hunk->colored_start;
370
371         return 0;
372 }
373
374 static int is_octal(const char *p, size_t len)
375 {
376         if (!len)
377                 return 0;
378
379         while (len--)
380                 if (*p < '0' || *(p++) > '7')
381                         return 0;
382         return 1;
383 }
384
385 static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
386 {
387         struct strvec args = STRVEC_INIT;
388         const char *diff_algorithm = s->s.interactive_diff_algorithm;
389         struct strbuf *plain = &s->plain, *colored = NULL;
390         struct child_process cp = CHILD_PROCESS_INIT;
391         char *p, *pend, *colored_p = NULL, *colored_pend = NULL, marker = '\0';
392         size_t file_diff_alloc = 0, i, color_arg_index;
393         struct file_diff *file_diff = NULL;
394         struct hunk *hunk = NULL;
395         int res;
396
397         strvec_pushv(&args, s->mode->diff_cmd);
398         if (diff_algorithm)
399                 strvec_pushf(&args, "--diff-algorithm=%s", diff_algorithm);
400         if (s->revision) {
401                 struct object_id oid;
402                 strvec_push(&args,
403                             /* could be on an unborn branch */
404                             !strcmp("HEAD", s->revision) &&
405                             get_oid("HEAD", &oid) ?
406                             empty_tree_oid_hex() : s->revision);
407         }
408         color_arg_index = args.nr;
409         /* Use `--no-color` explicitly, just in case `diff.color = always`. */
410         strvec_pushl(&args, "--no-color", "-p", "--", NULL);
411         for (i = 0; i < ps->nr; i++)
412                 strvec_push(&args, ps->items[i].original);
413
414         setup_child_process(s, &cp, NULL);
415         cp.argv = args.v;
416         res = capture_command(&cp, plain, 0);
417         if (res) {
418                 strvec_clear(&args);
419                 return error(_("could not parse diff"));
420         }
421         if (!plain->len) {
422                 strvec_clear(&args);
423                 return 0;
424         }
425         strbuf_complete_line(plain);
426
427         if (want_color_fd(1, -1)) {
428                 struct child_process colored_cp = CHILD_PROCESS_INIT;
429                 const char *diff_filter = s->s.interactive_diff_filter;
430
431                 setup_child_process(s, &colored_cp, NULL);
432                 xsnprintf((char *)args.v[color_arg_index], 8, "--color");
433                 colored_cp.argv = args.v;
434                 colored = &s->colored;
435                 res = capture_command(&colored_cp, colored, 0);
436                 strvec_clear(&args);
437                 if (res)
438                         return error(_("could not parse colored diff"));
439
440                 if (diff_filter) {
441                         struct child_process filter_cp = CHILD_PROCESS_INIT;
442
443                         setup_child_process(s, &filter_cp,
444                                             diff_filter, NULL);
445                         filter_cp.git_cmd = 0;
446                         filter_cp.use_shell = 1;
447                         strbuf_reset(&s->buf);
448                         if (pipe_command(&filter_cp,
449                                          colored->buf, colored->len,
450                                          &s->buf, colored->len,
451                                          NULL, 0) < 0)
452                                 return error(_("failed to run '%s'"),
453                                              diff_filter);
454                         strbuf_swap(colored, &s->buf);
455                 }
456
457                 strbuf_complete_line(colored);
458                 colored_p = colored->buf;
459                 colored_pend = colored_p + colored->len;
460         }
461         strvec_clear(&args);
462
463         /* parse files and hunks */
464         p = plain->buf;
465         pend = p + plain->len;
466         while (p != pend) {
467                 char *eol = memchr(p, '\n', pend - p);
468                 const char *deleted = NULL, *mode_change = NULL;
469
470                 if (!eol)
471                         eol = pend;
472
473                 if (starts_with(p, "diff ")) {
474                         ALLOC_GROW_BY(s->file_diff, s->file_diff_nr, 1,
475                                    file_diff_alloc);
476                         file_diff = s->file_diff + s->file_diff_nr - 1;
477                         hunk = &file_diff->head;
478                         hunk->start = p - plain->buf;
479                         if (colored_p)
480                                 hunk->colored_start = colored_p - colored->buf;
481                         marker = '\0';
482                 } else if (p == plain->buf)
483                         BUG("diff starts with unexpected line:\n"
484                             "%.*s\n", (int)(eol - p), p);
485                 else if (file_diff->deleted)
486                         ; /* keep the rest of the file in a single "hunk" */
487                 else if (starts_with(p, "@@ ") ||
488                          (hunk == &file_diff->head &&
489                           (skip_prefix(p, "deleted file", &deleted)))) {
490                         if (marker == '-' || marker == '+')
491                                 /*
492                                  * Should not happen; previous hunk did not end
493                                  * in a context line? Handle it anyway.
494                                  */
495                                 hunk->splittable_into++;
496
497                         ALLOC_GROW_BY(file_diff->hunk, file_diff->hunk_nr, 1,
498                                    file_diff->hunk_alloc);
499                         hunk = file_diff->hunk + file_diff->hunk_nr - 1;
500
501                         hunk->start = p - plain->buf;
502                         if (colored)
503                                 hunk->colored_start = colored_p - colored->buf;
504
505                         if (deleted)
506                                 file_diff->deleted = 1;
507                         else if (parse_hunk_header(s, hunk) < 0)
508                                 return -1;
509
510                         /*
511                          * Start counting into how many hunks this one can be
512                          * split
513                          */
514                         marker = *p;
515                 } else if (hunk == &file_diff->head &&
516                            starts_with(p, "new file")) {
517                         file_diff->added = 1;
518                 } else if (hunk == &file_diff->head &&
519                            skip_prefix(p, "old mode ", &mode_change) &&
520                            is_octal(mode_change, eol - mode_change)) {
521                         if (file_diff->mode_change)
522                                 BUG("double mode change?\n\n%.*s",
523                                     (int)(eol - plain->buf), plain->buf);
524                         if (file_diff->hunk_nr)
525                                 BUG("mode change in the middle?\n\n%.*s",
526                                     (int)(eol - plain->buf), plain->buf);
527
528                         /*
529                          * Do *not* change `hunk`: the mode change pseudo-hunk
530                          * is _part of_ the header "hunk".
531                          */
532                         file_diff->mode_change = 1;
533                         ALLOC_GROW_BY(file_diff->hunk, file_diff->hunk_nr, 1,
534                                    file_diff->hunk_alloc);
535                         file_diff->hunk->start = p - plain->buf;
536                         if (colored_p)
537                                 file_diff->hunk->colored_start =
538                                         colored_p - colored->buf;
539                 } else if (hunk == &file_diff->head &&
540                            skip_prefix(p, "new mode ", &mode_change) &&
541                            is_octal(mode_change, eol - mode_change)) {
542
543                         /*
544                          * Extend the "mode change" pseudo-hunk to include also
545                          * the "new mode" line.
546                          */
547                         if (!file_diff->mode_change)
548                                 BUG("'new mode' without 'old mode'?\n\n%.*s",
549                                     (int)(eol - plain->buf), plain->buf);
550                         if (file_diff->hunk_nr != 1)
551                                 BUG("mode change in the middle?\n\n%.*s",
552                                     (int)(eol - plain->buf), plain->buf);
553                         if (p - plain->buf != file_diff->hunk->end)
554                                 BUG("'new mode' does not immediately follow "
555                                     "'old mode'?\n\n%.*s",
556                                     (int)(eol - plain->buf), plain->buf);
557                 } else if (hunk == &file_diff->head &&
558                            starts_with(p, "Binary files "))
559                         file_diff->binary = 1;
560
561                 if (!!file_diff->deleted + !!file_diff->added +
562                     !!file_diff->mode_change > 1)
563                         BUG("diff can only contain delete *or* add *or* a "
564                             "mode change?!?\n%.*s",
565                             (int)(eol - (plain->buf + file_diff->head.start)),
566                             plain->buf + file_diff->head.start);
567
568                 if ((marker == '-' || marker == '+') && *p == ' ')
569                         hunk->splittable_into++;
570                 if (marker && *p != '\\')
571                         marker = *p;
572
573                 p = eol == pend ? pend : eol + 1;
574                 hunk->end = p - plain->buf;
575
576                 if (colored) {
577                         char *colored_eol = memchr(colored_p, '\n',
578                                                    colored_pend - colored_p);
579                         if (colored_eol)
580                                 colored_p = colored_eol + 1;
581                         else if (p != pend)
582                                 /* colored shorter than non-colored? */
583                                 goto mismatched_output;
584                         else
585                                 colored_p = colored_pend;
586
587                         hunk->colored_end = colored_p - colored->buf;
588                 }
589
590                 if (mode_change) {
591                         if (file_diff->hunk_nr != 1)
592                                 BUG("mode change in hunk #%d???",
593                                     (int)file_diff->hunk_nr);
594                         /* Adjust the end of the "mode change" pseudo-hunk */
595                         file_diff->hunk->end = hunk->end;
596                         if (colored)
597                                 file_diff->hunk->colored_end = hunk->colored_end;
598                 }
599         }
600
601         if (marker == '-' || marker == '+')
602                 /*
603                  * Last hunk ended in non-context line (i.e. it appended lines
604                  * to the file, so there are no trailing context lines).
605                  */
606                 hunk->splittable_into++;
607
608         /* non-colored shorter than colored? */
609         if (colored_p != colored_pend) {
610 mismatched_output:
611                 error(_("mismatched output from interactive.diffFilter"));
612                 advise(_("Your filter must maintain a one-to-one correspondence\n"
613                          "between its input and output lines."));
614                 return -1;
615         }
616
617         return 0;
618 }
619
620 static size_t find_next_line(struct strbuf *sb, size_t offset)
621 {
622         char *eol;
623
624         if (offset >= sb->len)
625                 BUG("looking for next line beyond buffer (%d >= %d)\n%s",
626                     (int)offset, (int)sb->len, sb->buf);
627
628         eol = memchr(sb->buf + offset, '\n', sb->len - offset);
629         if (!eol)
630                 return sb->len;
631         return eol - sb->buf + 1;
632 }
633
634 static void render_hunk(struct add_p_state *s, struct hunk *hunk,
635                         ssize_t delta, int colored, struct strbuf *out)
636 {
637         struct hunk_header *header = &hunk->header;
638
639         if (hunk->header.old_offset != 0 || hunk->header.new_offset != 0) {
640                 /*
641                  * Generate the hunk header dynamically, except for special
642                  * hunks (such as the diff header).
643                  */
644                 const char *p;
645                 size_t len;
646                 unsigned long old_offset = header->old_offset;
647                 unsigned long new_offset = header->new_offset;
648
649                 if (!colored) {
650                         p = s->plain.buf + header->extra_start;
651                         len = header->extra_end - header->extra_start;
652                 } else {
653                         strbuf_addstr(out, s->s.fraginfo_color);
654                         p = s->colored.buf + header->colored_extra_start;
655                         len = header->colored_extra_end
656                                 - header->colored_extra_start;
657                 }
658
659                 if (s->mode->is_reverse)
660                         old_offset -= delta;
661                 else
662                         new_offset += delta;
663
664                 strbuf_addf(out, "@@ -%lu,%lu +%lu,%lu @@",
665                             old_offset, header->old_count,
666                             new_offset, header->new_count);
667                 if (len)
668                         strbuf_add(out, p, len);
669                 else if (colored)
670                         strbuf_addf(out, "%s\n", GIT_COLOR_RESET);
671                 else
672                         strbuf_addch(out, '\n');
673         }
674
675         if (colored)
676                 strbuf_add(out, s->colored.buf + hunk->colored_start,
677                            hunk->colored_end - hunk->colored_start);
678         else
679                 strbuf_add(out, s->plain.buf + hunk->start,
680                            hunk->end - hunk->start);
681 }
682
683 static void render_diff_header(struct add_p_state *s,
684                                struct file_diff *file_diff, int colored,
685                                struct strbuf *out)
686 {
687         /*
688          * If there was a mode change, the first hunk is a pseudo hunk that
689          * corresponds to the mode line in the header. If the user did not want
690          * to stage that "hunk", we actually have to cut it out from the header.
691          */
692         int skip_mode_change =
693                 file_diff->mode_change && file_diff->hunk->use != USE_HUNK;
694         struct hunk *head = &file_diff->head, *first = file_diff->hunk;
695
696         if (!skip_mode_change) {
697                 render_hunk(s, head, 0, colored, out);
698                 return;
699         }
700
701         if (colored) {
702                 const char *p = s->colored.buf;
703
704                 strbuf_add(out, p + head->colored_start,
705                             first->colored_start - head->colored_start);
706                 strbuf_add(out, p + first->colored_end,
707                             head->colored_end - first->colored_end);
708         } else {
709                 const char *p = s->plain.buf;
710
711                 strbuf_add(out, p + head->start, first->start - head->start);
712                 strbuf_add(out, p + first->end, head->end - first->end);
713         }
714 }
715
716 /* Coalesce hunks again that were split */
717 static int merge_hunks(struct add_p_state *s, struct file_diff *file_diff,
718                        size_t *hunk_index, int use_all, struct hunk *merged)
719 {
720         size_t i = *hunk_index, delta;
721         struct hunk *hunk = file_diff->hunk + i;
722         /* `header` corresponds to the merged hunk */
723         struct hunk_header *header = &merged->header, *next;
724
725         if (!use_all && hunk->use != USE_HUNK)
726                 return 0;
727
728         *merged = *hunk;
729         /* We simply skip the colored part (if any) when merging hunks */
730         merged->colored_start = merged->colored_end = 0;
731
732         for (; i + 1 < file_diff->hunk_nr; i++) {
733                 hunk++;
734                 next = &hunk->header;
735
736                 /*
737                  * Stop merging hunks when:
738                  *
739                  * - the hunk is not selected for use, or
740                  * - the hunk does not overlap with the already-merged hunk(s)
741                  */
742                 if ((!use_all && hunk->use != USE_HUNK) ||
743                     header->new_offset >= next->new_offset + merged->delta ||
744                     header->new_offset + header->new_count
745                     < next->new_offset + merged->delta)
746                         break;
747
748                 /*
749                  * If the hunks were not edited, and overlap, we can simply
750                  * extend the line range.
751                  */
752                 if (merged->start < hunk->start && merged->end > hunk->start) {
753                         merged->end = hunk->end;
754                         merged->colored_end = hunk->colored_end;
755                         delta = 0;
756                 } else {
757                         const char *plain = s->plain.buf;
758                         size_t  overlapping_line_count = header->new_offset
759                                 + header->new_count - merged->delta
760                                 - next->new_offset;
761                         size_t overlap_end = hunk->start;
762                         size_t overlap_start = overlap_end;
763                         size_t overlap_next, len, j;
764
765                         /*
766                          * One of the hunks was edited: the modified hunk was
767                          * appended to the strbuf `s->plain`.
768                          *
769                          * Let's ensure that at least the last context line of
770                          * the first hunk overlaps with the corresponding line
771                          * of the second hunk, and then merge.
772                          */
773                         for (j = 0; j < overlapping_line_count; j++) {
774                                 overlap_next = find_next_line(&s->plain,
775                                                               overlap_end);
776
777                                 if (overlap_next > hunk->end)
778                                         BUG("failed to find %d context lines "
779                                             "in:\n%.*s",
780                                             (int)overlapping_line_count,
781                                             (int)(hunk->end - hunk->start),
782                                             plain + hunk->start);
783
784                                 if (plain[overlap_end] != ' ')
785                                         return error(_("expected context line "
786                                                        "#%d in\n%.*s"),
787                                                      (int)(j + 1),
788                                                      (int)(hunk->end
789                                                            - hunk->start),
790                                                      plain + hunk->start);
791
792                                 overlap_start = overlap_end;
793                                 overlap_end = overlap_next;
794                         }
795                         len = overlap_end - overlap_start;
796
797                         if (len > merged->end - merged->start ||
798                             memcmp(plain + merged->end - len,
799                                    plain + overlap_start, len))
800                                 return error(_("hunks do not overlap:\n%.*s\n"
801                                                "\tdoes not end with:\n%.*s"),
802                                              (int)(merged->end - merged->start),
803                                              plain + merged->start,
804                                              (int)len, plain + overlap_start);
805
806                         /*
807                          * Since the start-end ranges are not adjacent, we
808                          * cannot simply take the union of the ranges. To
809                          * address that, we temporarily append the union of the
810                          * lines to the `plain` strbuf.
811                          */
812                         if (merged->end != s->plain.len) {
813                                 size_t start = s->plain.len;
814
815                                 strbuf_add(&s->plain, plain + merged->start,
816                                            merged->end - merged->start);
817                                 plain = s->plain.buf;
818                                 merged->start = start;
819                                 merged->end = s->plain.len;
820                         }
821
822                         strbuf_add(&s->plain,
823                                    plain + overlap_end,
824                                    hunk->end - overlap_end);
825                         merged->end = s->plain.len;
826                         merged->splittable_into += hunk->splittable_into;
827                         delta = merged->delta;
828                         merged->delta += hunk->delta;
829                 }
830
831                 header->old_count = next->old_offset + next->old_count
832                         - header->old_offset;
833                 header->new_count = next->new_offset + delta
834                         + next->new_count - header->new_offset;
835         }
836
837         if (i == *hunk_index)
838                 return 0;
839
840         *hunk_index = i;
841         return 1;
842 }
843
844 static void reassemble_patch(struct add_p_state *s,
845                              struct file_diff *file_diff, int use_all,
846                              struct strbuf *out)
847 {
848         struct hunk *hunk;
849         size_t save_len = s->plain.len, i;
850         ssize_t delta = 0;
851
852         render_diff_header(s, file_diff, 0, out);
853
854         for (i = file_diff->mode_change; i < file_diff->hunk_nr; i++) {
855                 struct hunk merged = { 0 };
856
857                 hunk = file_diff->hunk + i;
858                 if (!use_all && hunk->use != USE_HUNK)
859                         delta += hunk->header.old_count
860                                 - hunk->header.new_count;
861                 else {
862                         /* merge overlapping hunks into a temporary hunk */
863                         if (merge_hunks(s, file_diff, &i, use_all, &merged))
864                                 hunk = &merged;
865
866                         render_hunk(s, hunk, delta, 0, out);
867
868                         /*
869                          * In case `merge_hunks()` used `plain` as a scratch
870                          * pad (this happens when an edited hunk had to be
871                          * coalesced with another hunk).
872                          */
873                         strbuf_setlen(&s->plain, save_len);
874
875                         delta += hunk->delta;
876                 }
877         }
878 }
879
880 static int split_hunk(struct add_p_state *s, struct file_diff *file_diff,
881                        size_t hunk_index)
882 {
883         int colored = !!s->colored.len, first = 1;
884         struct hunk *hunk = file_diff->hunk + hunk_index;
885         size_t splittable_into;
886         size_t end, colored_end, current, colored_current = 0, context_line_count;
887         struct hunk_header remaining, *header;
888         char marker, ch;
889
890         if (hunk_index >= file_diff->hunk_nr)
891                 BUG("invalid hunk index: %d (must be >= 0 and < %d)",
892                     (int)hunk_index, (int)file_diff->hunk_nr);
893
894         if (hunk->splittable_into < 2)
895                 return 0;
896         splittable_into = hunk->splittable_into;
897
898         end = hunk->end;
899         colored_end = hunk->colored_end;
900
901         remaining = hunk->header;
902
903         file_diff->hunk_nr += splittable_into - 1;
904         ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr, file_diff->hunk_alloc);
905         if (hunk_index + splittable_into < file_diff->hunk_nr)
906                 memmove(file_diff->hunk + hunk_index + splittable_into,
907                         file_diff->hunk + hunk_index + 1,
908                         (file_diff->hunk_nr - hunk_index - splittable_into)
909                         * sizeof(*hunk));
910         hunk = file_diff->hunk + hunk_index;
911         hunk->splittable_into = 1;
912         memset(hunk + 1, 0, (splittable_into - 1) * sizeof(*hunk));
913
914         header = &hunk->header;
915         header->old_count = header->new_count = 0;
916
917         current = hunk->start;
918         if (colored)
919                 colored_current = hunk->colored_start;
920         marker = '\0';
921         context_line_count = 0;
922
923         while (splittable_into > 1) {
924                 ch = s->plain.buf[current];
925
926                 if (!ch)
927                         BUG("buffer overrun while splitting hunks");
928
929                 /*
930                  * Is this the first context line after a chain of +/- lines?
931                  * Then record the start of the next split hunk.
932                  */
933                 if ((marker == '-' || marker == '+') && ch == ' ') {
934                         first = 0;
935                         hunk[1].start = current;
936                         if (colored)
937                                 hunk[1].colored_start = colored_current;
938                         context_line_count = 0;
939                 }
940
941                 /*
942                  * Was the previous line a +/- one? Alternatively, is this the
943                  * first line (and not a +/- one)?
944                  *
945                  * Then just increment the appropriate counter and continue
946                  * with the next line.
947                  */
948                 if (marker != ' ' || (ch != '-' && ch != '+')) {
949 next_hunk_line:
950                         /* Comment lines are attached to the previous line */
951                         if (ch == '\\')
952                                 ch = marker ? marker : ' ';
953
954                         /* current hunk not done yet */
955                         if (ch == ' ')
956                                 context_line_count++;
957                         else if (ch == '-')
958                                 header->old_count++;
959                         else if (ch == '+')
960                                 header->new_count++;
961                         else
962                                 BUG("unhandled diff marker: '%c'", ch);
963                         marker = ch;
964                         current = find_next_line(&s->plain, current);
965                         if (colored)
966                                 colored_current =
967                                         find_next_line(&s->colored,
968                                                        colored_current);
969                         continue;
970                 }
971
972                 /*
973                  * We got us the start of a new hunk!
974                  *
975                  * This is a context line, so it is shared with the previous
976                  * hunk, if any.
977                  */
978
979                 if (first) {
980                         if (header->old_count || header->new_count)
981                                 BUG("counts are off: %d/%d",
982                                     (int)header->old_count,
983                                     (int)header->new_count);
984
985                         header->old_count = context_line_count;
986                         header->new_count = context_line_count;
987                         context_line_count = 0;
988                         first = 0;
989                         goto next_hunk_line;
990                 }
991
992                 remaining.old_offset += header->old_count;
993                 remaining.old_count -= header->old_count;
994                 remaining.new_offset += header->new_count;
995                 remaining.new_count -= header->new_count;
996
997                 /* initialize next hunk header's offsets */
998                 hunk[1].header.old_offset =
999                         header->old_offset + header->old_count;
1000                 hunk[1].header.new_offset =
1001                         header->new_offset + header->new_count;
1002
1003                 /* add one split hunk */
1004                 header->old_count += context_line_count;
1005                 header->new_count += context_line_count;
1006
1007                 hunk->end = current;
1008                 if (colored)
1009                         hunk->colored_end = colored_current;
1010
1011                 hunk++;
1012                 hunk->splittable_into = 1;
1013                 hunk->use = hunk[-1].use;
1014                 header = &hunk->header;
1015
1016                 header->old_count = header->new_count = context_line_count;
1017                 context_line_count = 0;
1018
1019                 splittable_into--;
1020                 marker = ch;
1021         }
1022
1023         /* last hunk simply gets the rest */
1024         if (header->old_offset != remaining.old_offset)
1025                 BUG("miscounted old_offset: %lu != %lu",
1026                     header->old_offset, remaining.old_offset);
1027         if (header->new_offset != remaining.new_offset)
1028                 BUG("miscounted new_offset: %lu != %lu",
1029                     header->new_offset, remaining.new_offset);
1030         header->old_count = remaining.old_count;
1031         header->new_count = remaining.new_count;
1032         hunk->end = end;
1033         if (colored)
1034                 hunk->colored_end = colored_end;
1035
1036         return 0;
1037 }
1038
1039 static void recolor_hunk(struct add_p_state *s, struct hunk *hunk)
1040 {
1041         const char *plain = s->plain.buf;
1042         size_t current, eol, next;
1043
1044         if (!s->colored.len)
1045                 return;
1046
1047         hunk->colored_start = s->colored.len;
1048         for (current = hunk->start; current < hunk->end; ) {
1049                 for (eol = current; eol < hunk->end; eol++)
1050                         if (plain[eol] == '\n')
1051                                 break;
1052                 next = eol + (eol < hunk->end);
1053                 if (eol > current && plain[eol - 1] == '\r')
1054                         eol--;
1055
1056                 strbuf_addstr(&s->colored,
1057                               plain[current] == '-' ?
1058                               s->s.file_old_color :
1059                               plain[current] == '+' ?
1060                               s->s.file_new_color :
1061                               s->s.context_color);
1062                 strbuf_add(&s->colored, plain + current, eol - current);
1063                 strbuf_addstr(&s->colored, GIT_COLOR_RESET);
1064                 if (next > eol)
1065                         strbuf_add(&s->colored, plain + eol, next - eol);
1066                 current = next;
1067         }
1068         hunk->colored_end = s->colored.len;
1069 }
1070
1071 static int edit_hunk_manually(struct add_p_state *s, struct hunk *hunk)
1072 {
1073         size_t i;
1074
1075         strbuf_reset(&s->buf);
1076         strbuf_commented_addf(&s->buf, _("Manual hunk edit mode -- see bottom for "
1077                                       "a quick guide.\n"));
1078         render_hunk(s, hunk, 0, 0, &s->buf);
1079         strbuf_commented_addf(&s->buf,
1080                               _("---\n"
1081                                 "To remove '%c' lines, make them ' ' lines "
1082                                 "(context).\n"
1083                                 "To remove '%c' lines, delete them.\n"
1084                                 "Lines starting with %c will be removed.\n"),
1085                               s->mode->is_reverse ? '+' : '-',
1086                               s->mode->is_reverse ? '-' : '+',
1087                               comment_line_char);
1088         strbuf_commented_addf(&s->buf, "%s", _(s->mode->edit_hunk_hint));
1089         /*
1090          * TRANSLATORS: 'it' refers to the patch mentioned in the previous
1091          * messages.
1092          */
1093         strbuf_commented_addf(&s->buf,
1094                               _("If it does not apply cleanly, you will be "
1095                                 "given an opportunity to\n"
1096                                 "edit again.  If all lines of the hunk are "
1097                                 "removed, then the edit is\n"
1098                                 "aborted and the hunk is left unchanged.\n"));
1099
1100         if (strbuf_edit_interactively(&s->buf, "addp-hunk-edit.diff", NULL) < 0)
1101                 return -1;
1102
1103         /* strip out commented lines */
1104         hunk->start = s->plain.len;
1105         for (i = 0; i < s->buf.len; ) {
1106                 size_t next = find_next_line(&s->buf, i);
1107
1108                 if (s->buf.buf[i] != comment_line_char)
1109                         strbuf_add(&s->plain, s->buf.buf + i, next - i);
1110                 i = next;
1111         }
1112
1113         hunk->end = s->plain.len;
1114         if (hunk->end == hunk->start)
1115                 /* The user aborted editing by deleting everything */
1116                 return 0;
1117
1118         recolor_hunk(s, hunk);
1119
1120         /*
1121          * If the hunk header is intact, parse it, otherwise simply use the
1122          * hunk header prior to editing (which will adjust `hunk->start` to
1123          * skip the hunk header).
1124          */
1125         if (s->plain.buf[hunk->start] == '@' &&
1126             parse_hunk_header(s, hunk) < 0)
1127                 return error(_("could not parse hunk header"));
1128
1129         return 1;
1130 }
1131
1132 static ssize_t recount_edited_hunk(struct add_p_state *s, struct hunk *hunk,
1133                                    size_t orig_old_count, size_t orig_new_count)
1134 {
1135         struct hunk_header *header = &hunk->header;
1136         size_t i;
1137
1138         header->old_count = header->new_count = 0;
1139         for (i = hunk->start; i < hunk->end; ) {
1140                 switch (s->plain.buf[i]) {
1141                 case '-':
1142                         header->old_count++;
1143                         break;
1144                 case '+':
1145                         header->new_count++;
1146                         break;
1147                 case ' ': case '\r': case '\n':
1148                         header->old_count++;
1149                         header->new_count++;
1150                         break;
1151                 }
1152
1153                 i = find_next_line(&s->plain, i);
1154         }
1155
1156         return orig_old_count - orig_new_count
1157                 - header->old_count + header->new_count;
1158 }
1159
1160 static int run_apply_check(struct add_p_state *s,
1161                            struct file_diff *file_diff)
1162 {
1163         struct child_process cp = CHILD_PROCESS_INIT;
1164
1165         strbuf_reset(&s->buf);
1166         reassemble_patch(s, file_diff, 1, &s->buf);
1167
1168         setup_child_process(s, &cp,
1169                             "apply", "--check", NULL);
1170         strvec_pushv(&cp.args, s->mode->apply_check_args);
1171         if (pipe_command(&cp, s->buf.buf, s->buf.len, NULL, 0, NULL, 0))
1172                 return error(_("'git apply --cached' failed"));
1173
1174         return 0;
1175 }
1176
1177 static int read_single_character(struct add_p_state *s)
1178 {
1179         if (s->s.use_single_key) {
1180                 int res = read_key_without_echo(&s->answer);
1181                 printf("%s\n", res == EOF ? "" : s->answer.buf);
1182                 return res;
1183         }
1184
1185         if (git_read_line_interactively(&s->answer) == EOF)
1186                 return EOF;
1187         return 0;
1188 }
1189
1190 static int prompt_yesno(struct add_p_state *s, const char *prompt)
1191 {
1192         for (;;) {
1193                 color_fprintf(stdout, s->s.prompt_color, "%s", _(prompt));
1194                 fflush(stdout);
1195                 if (read_single_character(s) == EOF)
1196                         return -1;
1197                 switch (tolower(s->answer.buf[0])) {
1198                 case 'n': return 0;
1199                 case 'y': return 1;
1200                 }
1201         }
1202 }
1203
1204 static int edit_hunk_loop(struct add_p_state *s,
1205                           struct file_diff *file_diff, struct hunk *hunk)
1206 {
1207         size_t plain_len = s->plain.len, colored_len = s->colored.len;
1208         struct hunk backup;
1209
1210         backup = *hunk;
1211
1212         for (;;) {
1213                 int res = edit_hunk_manually(s, hunk);
1214                 if (res == 0) {
1215                         /* abandoned */
1216                         *hunk = backup;
1217                         return -1;
1218                 }
1219
1220                 if (res > 0) {
1221                         hunk->delta +=
1222                                 recount_edited_hunk(s, hunk,
1223                                                     backup.header.old_count,
1224                                                     backup.header.new_count);
1225                         if (!run_apply_check(s, file_diff))
1226                                 return 0;
1227                 }
1228
1229                 /* Drop edits (they were appended to s->plain) */
1230                 strbuf_setlen(&s->plain, plain_len);
1231                 strbuf_setlen(&s->colored, colored_len);
1232                 *hunk = backup;
1233
1234                 /*
1235                  * TRANSLATORS: do not translate [y/n]
1236                  * The program will only accept that input at this point.
1237                  * Consider translating (saying "no" discards!) as
1238                  * (saying "n" for "no" discards!) if the translation
1239                  * of the word "no" does not start with n.
1240                  */
1241                 res = prompt_yesno(s, _("Your edited hunk does not apply. "
1242                                         "Edit again (saying \"no\" discards!) "
1243                                         "[y/n]? "));
1244                 if (res < 1)
1245                         return -1;
1246         }
1247 }
1248
1249 static int apply_for_checkout(struct add_p_state *s, struct strbuf *diff,
1250                               int is_reverse)
1251 {
1252         const char *reverse = is_reverse ? "-R" : NULL;
1253         struct child_process check_index = CHILD_PROCESS_INIT;
1254         struct child_process check_worktree = CHILD_PROCESS_INIT;
1255         struct child_process apply_index = CHILD_PROCESS_INIT;
1256         struct child_process apply_worktree = CHILD_PROCESS_INIT;
1257         int applies_index, applies_worktree;
1258
1259         setup_child_process(s, &check_index,
1260                             "apply", "--cached", "--check", reverse, NULL);
1261         applies_index = !pipe_command(&check_index, diff->buf, diff->len,
1262                                       NULL, 0, NULL, 0);
1263
1264         setup_child_process(s, &check_worktree,
1265                             "apply", "--check", reverse, NULL);
1266         applies_worktree = !pipe_command(&check_worktree, diff->buf, diff->len,
1267                                          NULL, 0, NULL, 0);
1268
1269         if (applies_worktree && applies_index) {
1270                 setup_child_process(s, &apply_index,
1271                                     "apply", "--cached", reverse, NULL);
1272                 pipe_command(&apply_index, diff->buf, diff->len,
1273                              NULL, 0, NULL, 0);
1274
1275                 setup_child_process(s, &apply_worktree,
1276                                     "apply", reverse, NULL);
1277                 pipe_command(&apply_worktree, diff->buf, diff->len,
1278                              NULL, 0, NULL, 0);
1279
1280                 return 1;
1281         }
1282
1283         if (!applies_index) {
1284                 err(s, _("The selected hunks do not apply to the index!"));
1285                 if (prompt_yesno(s, _("Apply them to the worktree "
1286                                           "anyway? ")) > 0) {
1287                         setup_child_process(s, &apply_worktree,
1288                                             "apply", reverse, NULL);
1289                         return pipe_command(&apply_worktree, diff->buf,
1290                                             diff->len, NULL, 0, NULL, 0);
1291                 }
1292                 err(s, _("Nothing was applied.\n"));
1293         } else
1294                 /* As a last resort, show the diff to the user */
1295                 fwrite(diff->buf, diff->len, 1, stderr);
1296
1297         return 0;
1298 }
1299
1300 #define SUMMARY_HEADER_WIDTH 20
1301 #define SUMMARY_LINE_WIDTH 80
1302 static void summarize_hunk(struct add_p_state *s, struct hunk *hunk,
1303                            struct strbuf *out)
1304 {
1305         struct hunk_header *header = &hunk->header;
1306         struct strbuf *plain = &s->plain;
1307         size_t len = out->len, i;
1308
1309         strbuf_addf(out, " -%lu,%lu +%lu,%lu ",
1310                     header->old_offset, header->old_count,
1311                     header->new_offset, header->new_count);
1312         if (out->len - len < SUMMARY_HEADER_WIDTH)
1313                 strbuf_addchars(out, ' ',
1314                                 SUMMARY_HEADER_WIDTH + len - out->len);
1315         for (i = hunk->start; i < hunk->end; i = find_next_line(plain, i))
1316                 if (plain->buf[i] != ' ')
1317                         break;
1318         if (i < hunk->end)
1319                 strbuf_add(out, plain->buf + i, find_next_line(plain, i) - i);
1320         if (out->len - len > SUMMARY_LINE_WIDTH)
1321                 strbuf_setlen(out, len + SUMMARY_LINE_WIDTH);
1322         strbuf_complete_line(out);
1323 }
1324
1325 #define DISPLAY_HUNKS_LINES 20
1326 static size_t display_hunks(struct add_p_state *s,
1327                             struct file_diff *file_diff, size_t start_index)
1328 {
1329         size_t end_index = start_index + DISPLAY_HUNKS_LINES;
1330
1331         if (end_index > file_diff->hunk_nr)
1332                 end_index = file_diff->hunk_nr;
1333
1334         while (start_index < end_index) {
1335                 struct hunk *hunk = file_diff->hunk + start_index++;
1336
1337                 strbuf_reset(&s->buf);
1338                 strbuf_addf(&s->buf, "%c%2d: ", hunk->use == USE_HUNK ? '+'
1339                             : hunk->use == SKIP_HUNK ? '-' : ' ',
1340                             (int)start_index);
1341                 summarize_hunk(s, hunk, &s->buf);
1342                 fputs(s->buf.buf, stdout);
1343         }
1344
1345         return end_index;
1346 }
1347
1348 static const char help_patch_remainder[] =
1349 N_("j - leave this hunk undecided, see next undecided hunk\n"
1350    "J - leave this hunk undecided, see next hunk\n"
1351    "k - leave this hunk undecided, see previous undecided hunk\n"
1352    "K - leave this hunk undecided, see previous hunk\n"
1353    "g - select a hunk to go to\n"
1354    "/ - search for a hunk matching the given regex\n"
1355    "s - split the current hunk into smaller hunks\n"
1356    "e - manually edit the current hunk\n"
1357    "? - print help\n");
1358
1359 static int patch_update_file(struct add_p_state *s,
1360                              struct file_diff *file_diff)
1361 {
1362         size_t hunk_index = 0;
1363         ssize_t i, undecided_previous, undecided_next;
1364         struct hunk *hunk;
1365         char ch;
1366         struct child_process cp = CHILD_PROCESS_INIT;
1367         int colored = !!s->colored.len, quit = 0;
1368         enum prompt_mode_type prompt_mode_type;
1369         enum {
1370                 ALLOW_GOTO_PREVIOUS_HUNK = 1 << 0,
1371                 ALLOW_GOTO_PREVIOUS_UNDECIDED_HUNK = 1 << 1,
1372                 ALLOW_GOTO_NEXT_HUNK = 1 << 2,
1373                 ALLOW_GOTO_NEXT_UNDECIDED_HUNK = 1 << 3,
1374                 ALLOW_SEARCH_AND_GOTO = 1 << 4,
1375                 ALLOW_SPLIT = 1 << 5,
1376                 ALLOW_EDIT = 1 << 6
1377         } permitted = 0;
1378
1379         /* Empty added files have no hunks */
1380         if (!file_diff->hunk_nr && !file_diff->added)
1381                 return 0;
1382
1383         strbuf_reset(&s->buf);
1384         render_diff_header(s, file_diff, colored, &s->buf);
1385         fputs(s->buf.buf, stdout);
1386         for (;;) {
1387                 if (hunk_index >= file_diff->hunk_nr)
1388                         hunk_index = 0;
1389                 hunk = file_diff->hunk_nr
1390                                 ? file_diff->hunk + hunk_index
1391                                 : &file_diff->head;
1392                 undecided_previous = -1;
1393                 undecided_next = -1;
1394
1395                 if (file_diff->hunk_nr) {
1396                         for (i = hunk_index - 1; i >= 0; i--)
1397                                 if (file_diff->hunk[i].use == UNDECIDED_HUNK) {
1398                                         undecided_previous = i;
1399                                         break;
1400                                 }
1401
1402                         for (i = hunk_index + 1; i < file_diff->hunk_nr; i++)
1403                                 if (file_diff->hunk[i].use == UNDECIDED_HUNK) {
1404                                         undecided_next = i;
1405                                         break;
1406                                 }
1407                 }
1408
1409                 /* Everything decided? */
1410                 if (undecided_previous < 0 && undecided_next < 0 &&
1411                     hunk->use != UNDECIDED_HUNK)
1412                         break;
1413
1414                 strbuf_reset(&s->buf);
1415                 if (file_diff->hunk_nr) {
1416                         render_hunk(s, hunk, 0, colored, &s->buf);
1417                         fputs(s->buf.buf, stdout);
1418
1419                         strbuf_reset(&s->buf);
1420                         if (undecided_previous >= 0) {
1421                                 permitted |= ALLOW_GOTO_PREVIOUS_UNDECIDED_HUNK;
1422                                 strbuf_addstr(&s->buf, ",k");
1423                         }
1424                         if (hunk_index) {
1425                                 permitted |= ALLOW_GOTO_PREVIOUS_HUNK;
1426                                 strbuf_addstr(&s->buf, ",K");
1427                         }
1428                         if (undecided_next >= 0) {
1429                                 permitted |= ALLOW_GOTO_NEXT_UNDECIDED_HUNK;
1430                                 strbuf_addstr(&s->buf, ",j");
1431                         }
1432                         if (hunk_index + 1 < file_diff->hunk_nr) {
1433                                 permitted |= ALLOW_GOTO_NEXT_HUNK;
1434                                 strbuf_addstr(&s->buf, ",J");
1435                         }
1436                         if (file_diff->hunk_nr > 1) {
1437                                 permitted |= ALLOW_SEARCH_AND_GOTO;
1438                                 strbuf_addstr(&s->buf, ",g,/");
1439                         }
1440                         if (hunk->splittable_into > 1) {
1441                                 permitted |= ALLOW_SPLIT;
1442                                 strbuf_addstr(&s->buf, ",s");
1443                         }
1444                         if (hunk_index + 1 > file_diff->mode_change &&
1445                             !file_diff->deleted) {
1446                                 permitted |= ALLOW_EDIT;
1447                                 strbuf_addstr(&s->buf, ",e");
1448                         }
1449                 }
1450                 if (file_diff->deleted)
1451                         prompt_mode_type = PROMPT_DELETION;
1452                 else if (file_diff->added)
1453                         prompt_mode_type = PROMPT_ADDITION;
1454                 else if (file_diff->mode_change && !hunk_index)
1455                         prompt_mode_type = PROMPT_MODE_CHANGE;
1456                 else
1457                         prompt_mode_type = PROMPT_HUNK;
1458
1459                 color_fprintf(stdout, s->s.prompt_color,
1460                               "(%"PRIuMAX"/%"PRIuMAX") ",
1461                               (uintmax_t)hunk_index + 1,
1462                               (uintmax_t)(file_diff->hunk_nr
1463                                                 ? file_diff->hunk_nr
1464                                                 : 1));
1465                 color_fprintf(stdout, s->s.prompt_color,
1466                               _(s->mode->prompt_mode[prompt_mode_type]),
1467                               s->buf.buf);
1468                 fflush(stdout);
1469                 if (read_single_character(s) == EOF)
1470                         break;
1471
1472                 if (!s->answer.len)
1473                         continue;
1474                 ch = tolower(s->answer.buf[0]);
1475                 if (ch == 'y') {
1476                         hunk->use = USE_HUNK;
1477 soft_increment:
1478                         hunk_index = undecided_next < 0 ?
1479                                 file_diff->hunk_nr : undecided_next;
1480                 } else if (ch == 'n') {
1481                         hunk->use = SKIP_HUNK;
1482                         goto soft_increment;
1483                 } else if (ch == 'a') {
1484                         if (file_diff->hunk_nr) {
1485                                 for (; hunk_index < file_diff->hunk_nr; hunk_index++) {
1486                                         hunk = file_diff->hunk + hunk_index;
1487                                         if (hunk->use == UNDECIDED_HUNK)
1488                                                 hunk->use = USE_HUNK;
1489                                 }
1490                         } else if (hunk->use == UNDECIDED_HUNK) {
1491                                 hunk->use = USE_HUNK;
1492                         }
1493                 } else if (ch == 'd' || ch == 'q') {
1494                         if (file_diff->hunk_nr) {
1495                                 for (; hunk_index < file_diff->hunk_nr; hunk_index++) {
1496                                         hunk = file_diff->hunk + hunk_index;
1497                                         if (hunk->use == UNDECIDED_HUNK)
1498                                                 hunk->use = SKIP_HUNK;
1499                                 }
1500                         } else if (hunk->use == UNDECIDED_HUNK) {
1501                                 hunk->use = SKIP_HUNK;
1502                         }
1503                         if (ch == 'q') {
1504                                 quit = 1;
1505                                 break;
1506                         }
1507                 } else if (s->answer.buf[0] == 'K') {
1508                         if (permitted & ALLOW_GOTO_PREVIOUS_HUNK)
1509                                 hunk_index--;
1510                         else
1511                                 err(s, _("No previous hunk"));
1512                 } else if (s->answer.buf[0] == 'J') {
1513                         if (permitted & ALLOW_GOTO_NEXT_HUNK)
1514                                 hunk_index++;
1515                         else
1516                                 err(s, _("No next hunk"));
1517                 } else if (s->answer.buf[0] == 'k') {
1518                         if (permitted & ALLOW_GOTO_PREVIOUS_UNDECIDED_HUNK)
1519                                 hunk_index = undecided_previous;
1520                         else
1521                                 err(s, _("No previous hunk"));
1522                 } else if (s->answer.buf[0] == 'j') {
1523                         if (permitted & ALLOW_GOTO_NEXT_UNDECIDED_HUNK)
1524                                 hunk_index = undecided_next;
1525                         else
1526                                 err(s, _("No next hunk"));
1527                 } else if (s->answer.buf[0] == 'g') {
1528                         char *pend;
1529                         unsigned long response;
1530
1531                         if (!(permitted & ALLOW_SEARCH_AND_GOTO)) {
1532                                 err(s, _("No other hunks to goto"));
1533                                 continue;
1534                         }
1535                         strbuf_remove(&s->answer, 0, 1);
1536                         strbuf_trim(&s->answer);
1537                         i = hunk_index - DISPLAY_HUNKS_LINES / 2;
1538                         if (i < file_diff->mode_change)
1539                                 i = file_diff->mode_change;
1540                         while (s->answer.len == 0) {
1541                                 i = display_hunks(s, file_diff, i);
1542                                 printf("%s", i < file_diff->hunk_nr ?
1543                                        _("go to which hunk (<ret> to see "
1544                                          "more)? ") : _("go to which hunk? "));
1545                                 fflush(stdout);
1546                                 if (strbuf_getline(&s->answer,
1547                                                    stdin) == EOF)
1548                                         break;
1549                                 strbuf_trim_trailing_newline(&s->answer);
1550                         }
1551
1552                         strbuf_trim(&s->answer);
1553                         response = strtoul(s->answer.buf, &pend, 10);
1554                         if (*pend || pend == s->answer.buf)
1555                                 err(s, _("Invalid number: '%s'"),
1556                                     s->answer.buf);
1557                         else if (0 < response && response <= file_diff->hunk_nr)
1558                                 hunk_index = response - 1;
1559                         else
1560                                 err(s, Q_("Sorry, only %d hunk available.",
1561                                           "Sorry, only %d hunks available.",
1562                                           file_diff->hunk_nr),
1563                                     (int)file_diff->hunk_nr);
1564                 } else if (s->answer.buf[0] == '/') {
1565                         regex_t regex;
1566                         int ret;
1567
1568                         if (!(permitted & ALLOW_SEARCH_AND_GOTO)) {
1569                                 err(s, _("No other hunks to search"));
1570                                 continue;
1571                         }
1572                         strbuf_remove(&s->answer, 0, 1);
1573                         strbuf_trim_trailing_newline(&s->answer);
1574                         if (s->answer.len == 0) {
1575                                 printf("%s", _("search for regex? "));
1576                                 fflush(stdout);
1577                                 if (strbuf_getline(&s->answer,
1578                                                    stdin) == EOF)
1579                                         break;
1580                                 strbuf_trim_trailing_newline(&s->answer);
1581                                 if (s->answer.len == 0)
1582                                         continue;
1583                         }
1584                         ret = regcomp(&regex, s->answer.buf,
1585                                       REG_EXTENDED | REG_NOSUB | REG_NEWLINE);
1586                         if (ret) {
1587                                 char errbuf[1024];
1588
1589                                 regerror(ret, &regex, errbuf, sizeof(errbuf));
1590                                 err(s, _("Malformed search regexp %s: %s"),
1591                                     s->answer.buf, errbuf);
1592                                 continue;
1593                         }
1594                         i = hunk_index;
1595                         for (;;) {
1596                                 /* render the hunk into a scratch buffer */
1597                                 render_hunk(s, file_diff->hunk + i, 0, 0,
1598                                             &s->buf);
1599                                 if (regexec(&regex, s->buf.buf, 0, NULL, 0)
1600                                     != REG_NOMATCH)
1601                                         break;
1602                                 i++;
1603                                 if (i == file_diff->hunk_nr)
1604                                         i = 0;
1605                                 if (i != hunk_index)
1606                                         continue;
1607                                 err(s, _("No hunk matches the given pattern"));
1608                                 break;
1609                         }
1610                         hunk_index = i;
1611                 } else if (s->answer.buf[0] == 's') {
1612                         size_t splittable_into = hunk->splittable_into;
1613                         if (!(permitted & ALLOW_SPLIT))
1614                                 err(s, _("Sorry, cannot split this hunk"));
1615                         else if (!split_hunk(s, file_diff,
1616                                              hunk - file_diff->hunk))
1617                                 color_fprintf_ln(stdout, s->s.header_color,
1618                                                  _("Split into %d hunks."),
1619                                                  (int)splittable_into);
1620                 } else if (s->answer.buf[0] == 'e') {
1621                         if (!(permitted & ALLOW_EDIT))
1622                                 err(s, _("Sorry, cannot edit this hunk"));
1623                         else if (edit_hunk_loop(s, file_diff, hunk) >= 0) {
1624                                 hunk->use = USE_HUNK;
1625                                 goto soft_increment;
1626                         }
1627                 } else {
1628                         const char *p = _(help_patch_remainder), *eol = p;
1629
1630                         color_fprintf(stdout, s->s.help_color, "%s",
1631                                       _(s->mode->help_patch_text));
1632
1633                         /*
1634                          * Show only those lines of the remainder that are
1635                          * actually applicable with the current hunk.
1636                          */
1637                         for (; *p; p = eol + (*eol == '\n')) {
1638                                 eol = strchrnul(p, '\n');
1639
1640                                 /*
1641                                  * `s->buf` still contains the part of the
1642                                  * commands shown in the prompt that are not
1643                                  * always available.
1644                                  */
1645                                 if (*p != '?' && !strchr(s->buf.buf, *p))
1646                                         continue;
1647
1648                                 color_fprintf_ln(stdout, s->s.help_color,
1649                                                  "%.*s", (int)(eol - p), p);
1650                         }
1651                 }
1652         }
1653
1654         /* Any hunk to be used? */
1655         for (i = 0; i < file_diff->hunk_nr; i++)
1656                 if (file_diff->hunk[i].use == USE_HUNK)
1657                         break;
1658
1659         if (i < file_diff->hunk_nr ||
1660             (!file_diff->hunk_nr && file_diff->head.use == USE_HUNK)) {
1661                 /* At least one hunk selected: apply */
1662                 strbuf_reset(&s->buf);
1663                 reassemble_patch(s, file_diff, 0, &s->buf);
1664
1665                 discard_index(s->s.r->index);
1666                 if (s->mode->apply_for_checkout)
1667                         apply_for_checkout(s, &s->buf,
1668                                            s->mode->is_reverse);
1669                 else {
1670                         setup_child_process(s, &cp, "apply", NULL);
1671                         strvec_pushv(&cp.args, s->mode->apply_args);
1672                         if (pipe_command(&cp, s->buf.buf, s->buf.len,
1673                                          NULL, 0, NULL, 0))
1674                                 error(_("'git apply' failed"));
1675                 }
1676                 if (repo_read_index(s->s.r) >= 0)
1677                         repo_refresh_and_write_index(s->s.r, REFRESH_QUIET, 0,
1678                                                      1, NULL, NULL, NULL);
1679         }
1680
1681         putchar('\n');
1682         return quit;
1683 }
1684
1685 int run_add_p(struct repository *r, enum add_p_mode mode,
1686               const char *revision, const struct pathspec *ps)
1687 {
1688         struct add_p_state s = {
1689                 { r }, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
1690         };
1691         size_t i, binary_count = 0;
1692
1693         init_add_i_state(&s.s, r);
1694
1695         if (mode == ADD_P_STASH)
1696                 s.mode = &patch_mode_stash;
1697         else if (mode == ADD_P_RESET) {
1698                 if (!revision || !strcmp(revision, "HEAD"))
1699                         s.mode = &patch_mode_reset_head;
1700                 else
1701                         s.mode = &patch_mode_reset_nothead;
1702         } else if (mode == ADD_P_CHECKOUT) {
1703                 if (!revision)
1704                         s.mode = &patch_mode_checkout_index;
1705                 else if (!strcmp(revision, "HEAD"))
1706                         s.mode = &patch_mode_checkout_head;
1707                 else
1708                         s.mode = &patch_mode_checkout_nothead;
1709         } else if (mode == ADD_P_WORKTREE) {
1710                 if (!revision)
1711                         s.mode = &patch_mode_checkout_index;
1712                 else if (!strcmp(revision, "HEAD"))
1713                         s.mode = &patch_mode_worktree_head;
1714                 else
1715                         s.mode = &patch_mode_worktree_nothead;
1716         } else
1717                 s.mode = &patch_mode_add;
1718         s.revision = revision;
1719
1720         if (discard_index(r->index) < 0 || repo_read_index(r) < 0 ||
1721             (!s.mode->index_only &&
1722              repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
1723                                           NULL, NULL, NULL) < 0) ||
1724             parse_diff(&s, ps) < 0) {
1725                 add_p_state_clear(&s);
1726                 return -1;
1727         }
1728
1729         for (i = 0; i < s.file_diff_nr; i++)
1730                 if (s.file_diff[i].binary && !s.file_diff[i].hunk_nr)
1731                         binary_count++;
1732                 else if (patch_update_file(&s, s.file_diff + i))
1733                         break;
1734
1735         if (s.file_diff_nr == 0)
1736                 fprintf(stderr, _("No changes.\n"));
1737         else if (binary_count == s.file_diff_nr)
1738                 fprintf(stderr, _("Only binary files changed.\n"));
1739
1740         add_p_state_clear(&s);
1741         return 0;
1742 }