Merge branch 'cb/maint-merge-recursive-fix' into cb/merge-recursive-fix
[git] / combine-diff.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "blob.h"
4 #include "diff.h"
5 #include "diffcore.h"
6 #include "quote.h"
7 #include "xdiff-interface.h"
8 #include "log-tree.h"
9
10 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
11 {
12         struct diff_queue_struct *q = &diff_queued_diff;
13         struct combine_diff_path *p;
14         int i;
15
16         if (!n) {
17                 struct combine_diff_path *list = NULL, **tail = &list;
18                 for (i = 0; i < q->nr; i++) {
19                         int len;
20                         const char *path;
21                         if (diff_unmodified_pair(q->queue[i]))
22                                 continue;
23                         path = q->queue[i]->two->path;
24                         len = strlen(path);
25                         p = xmalloc(combine_diff_path_size(num_parent, len));
26                         p->path = (char*) &(p->parent[num_parent]);
27                         memcpy(p->path, path, len);
28                         p->path[len] = 0;
29                         p->len = len;
30                         p->next = NULL;
31                         memset(p->parent, 0,
32                                sizeof(p->parent[0]) * num_parent);
33
34                         hashcpy(p->sha1, q->queue[i]->two->sha1);
35                         p->mode = q->queue[i]->two->mode;
36                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
37                         p->parent[n].mode = q->queue[i]->one->mode;
38                         p->parent[n].status = q->queue[i]->status;
39                         *tail = p;
40                         tail = &p->next;
41                 }
42                 return list;
43         }
44
45         for (p = curr; p; p = p->next) {
46                 int found = 0;
47                 if (!p->len)
48                         continue;
49                 for (i = 0; i < q->nr; i++) {
50                         const char *path;
51                         int len;
52
53                         if (diff_unmodified_pair(q->queue[i]))
54                                 continue;
55                         path = q->queue[i]->two->path;
56                         len = strlen(path);
57                         if (len == p->len && !memcmp(path, p->path, len)) {
58                                 found = 1;
59                                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
60                                 p->parent[n].mode = q->queue[i]->one->mode;
61                                 p->parent[n].status = q->queue[i]->status;
62                                 break;
63                         }
64                 }
65                 if (!found)
66                         p->len = 0;
67         }
68         return curr;
69 }
70
71 /* Lines lost from parent */
72 struct lline {
73         struct lline *next;
74         int len;
75         unsigned long parent_map;
76         char line[FLEX_ARRAY];
77 };
78
79 /* Lines surviving in the merge result */
80 struct sline {
81         struct lline *lost_head, **lost_tail;
82         char *bol;
83         int len;
84         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
85          * we did not change it).
86          * bit N is used for "interesting" lines, including context.
87          * bit (N+1) is used for "do not show deletion before this".
88          */
89         unsigned long flag;
90         unsigned long *p_lno;
91 };
92
93 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
94 {
95         char *blob;
96         enum object_type type;
97         if (is_null_sha1(sha1)) {
98                 /* deleted blob */
99                 *size = 0;
100                 return xcalloc(1, 1);
101         }
102         blob = read_sha1_file(sha1, &type, size);
103         if (type != OBJ_BLOB)
104                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
105         return blob;
106 }
107
108 static void append_lost(struct sline *sline, int n, const char *line, int len)
109 {
110         struct lline *lline;
111         unsigned long this_mask = (1UL<<n);
112         if (line[len-1] == '\n')
113                 len--;
114
115         /* Check to see if we can squash things */
116         if (sline->lost_head) {
117                 struct lline *last_one = NULL;
118                 /* We cannot squash it with earlier one */
119                 for (lline = sline->lost_head;
120                      lline;
121                      lline = lline->next)
122                         if (lline->parent_map & this_mask)
123                                 last_one = lline;
124                 lline = last_one ? last_one->next : sline->lost_head;
125                 while (lline) {
126                         if (lline->len == len &&
127                             !memcmp(lline->line, line, len)) {
128                                 lline->parent_map |= this_mask;
129                                 return;
130                         }
131                         lline = lline->next;
132                 }
133         }
134
135         lline = xmalloc(sizeof(*lline) + len + 1);
136         lline->len = len;
137         lline->next = NULL;
138         lline->parent_map = this_mask;
139         memcpy(lline->line, line, len);
140         lline->line[len] = 0;
141         *sline->lost_tail = lline;
142         sline->lost_tail = &lline->next;
143 }
144
145 struct combine_diff_state {
146         unsigned int lno;
147         int ob, on, nb, nn;
148         unsigned long nmask;
149         int num_parent;
150         int n;
151         struct sline *sline;
152         struct sline *lost_bucket;
153 };
154
155 static void consume_line(void *state_, char *line, unsigned long len)
156 {
157         struct combine_diff_state *state = state_;
158         if (5 < len && !memcmp("@@ -", line, 4)) {
159                 if (parse_hunk_header(line, len,
160                                       &state->ob, &state->on,
161                                       &state->nb, &state->nn))
162                         return;
163                 state->lno = state->nb;
164                 if (!state->nb)
165                         /* @@ -1,2 +0,0 @@ to remove the
166                          * first two lines...
167                          */
168                         state->nb = 1;
169                 if (state->nn == 0)
170                         /* @@ -X,Y +N,0 @@ removed Y lines
171                          * that would have come *after* line N
172                          * in the result.  Our lost buckets hang
173                          * to the line after the removed lines,
174                          */
175                         state->lost_bucket = &state->sline[state->nb];
176                 else
177                         state->lost_bucket = &state->sline[state->nb-1];
178                 if (!state->sline[state->nb-1].p_lno)
179                         state->sline[state->nb-1].p_lno =
180                                 xcalloc(state->num_parent,
181                                         sizeof(unsigned long));
182                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
183                 return;
184         }
185         if (!state->lost_bucket)
186                 return; /* not in any hunk yet */
187         switch (line[0]) {
188         case '-':
189                 append_lost(state->lost_bucket, state->n, line+1, len-1);
190                 break;
191         case '+':
192                 state->sline[state->lno-1].flag |= state->nmask;
193                 state->lno++;
194                 break;
195         }
196 }
197
198 static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
199                          struct sline *sline, unsigned int cnt, int n,
200                          int num_parent)
201 {
202         unsigned int p_lno, lno;
203         unsigned long nmask = (1UL << n);
204         xpparam_t xpp;
205         xdemitconf_t xecfg;
206         mmfile_t parent_file;
207         xdemitcb_t ecb;
208         struct combine_diff_state state;
209         unsigned long sz;
210
211         if (!cnt)
212                 return; /* result deleted */
213
214         parent_file.ptr = grab_blob(parent, &sz);
215         parent_file.size = sz;
216         memset(&xpp, 0, sizeof(xpp));
217         xpp.flags = XDF_NEED_MINIMAL;
218         memset(&xecfg, 0, sizeof(xecfg));
219         memset(&state, 0, sizeof(state));
220         state.nmask = nmask;
221         state.sline = sline;
222         state.lno = 1;
223         state.num_parent = num_parent;
224         state.n = n;
225
226         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
227                       &xpp, &xecfg, &ecb);
228         free(parent_file.ptr);
229
230         /* Assign line numbers for this parent.
231          *
232          * sline[lno].p_lno[n] records the first line number
233          * (counting from 1) for parent N if the final hunk display
234          * started by showing sline[lno] (possibly showing the lost
235          * lines attached to it first).
236          */
237         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
238                 struct lline *ll;
239                 sline[lno].p_lno[n] = p_lno;
240
241                 /* How many lines would this sline advance the p_lno? */
242                 ll = sline[lno].lost_head;
243                 while (ll) {
244                         if (ll->parent_map & nmask)
245                                 p_lno++; /* '-' means parent had it */
246                         ll = ll->next;
247                 }
248                 if (lno < cnt && !(sline[lno].flag & nmask))
249                         p_lno++; /* no '+' means parent had it */
250         }
251         sline[lno].p_lno[n] = p_lno; /* trailer */
252 }
253
254 static unsigned long context = 3;
255 static char combine_marker = '@';
256
257 static int interesting(struct sline *sline, unsigned long all_mask)
258 {
259         /* If some parents lost lines here, or if we have added to
260          * some parent, it is interesting.
261          */
262         return ((sline->flag & all_mask) || sline->lost_head);
263 }
264
265 static unsigned long adjust_hunk_tail(struct sline *sline,
266                                       unsigned long all_mask,
267                                       unsigned long hunk_begin,
268                                       unsigned long i)
269 {
270         /* i points at the first uninteresting line.  If the last line
271          * of the hunk was interesting only because it has some
272          * deletion, then it is not all that interesting for the
273          * purpose of giving trailing context lines.  This is because
274          * we output '-' line and then unmodified sline[i-1] itself in
275          * that case which gives us one extra context line.
276          */
277         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
278                 i--;
279         return i;
280 }
281
282 static unsigned long find_next(struct sline *sline,
283                                unsigned long mark,
284                                unsigned long i,
285                                unsigned long cnt,
286                                int look_for_uninteresting)
287 {
288         /* We have examined up to i-1 and are about to look at i.
289          * Find next interesting or uninteresting line.  Here,
290          * "interesting" does not mean interesting(), but marked by
291          * the give_context() function below (i.e. it includes context
292          * lines that are not interesting to interesting() function
293          * that are surrounded by interesting() ones.
294          */
295         while (i <= cnt)
296                 if (look_for_uninteresting
297                     ? !(sline[i].flag & mark)
298                     : (sline[i].flag & mark))
299                         return i;
300                 else
301                         i++;
302         return i;
303 }
304
305 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
306 {
307         unsigned long all_mask = (1UL<<num_parent) - 1;
308         unsigned long mark = (1UL<<num_parent);
309         unsigned long no_pre_delete = (2UL<<num_parent);
310         unsigned long i;
311
312         /* Two groups of interesting lines may have a short gap of
313          * uninteresting lines.  Connect such groups to give them a
314          * bit of context.
315          *
316          * We first start from what the interesting() function says,
317          * and mark them with "mark", and paint context lines with the
318          * mark.  So interesting() would still say false for such context
319          * lines but they are treated as "interesting" in the end.
320          */
321         i = find_next(sline, mark, 0, cnt, 0);
322         if (cnt < i)
323                 return 0;
324
325         while (i <= cnt) {
326                 unsigned long j = (context < i) ? (i - context) : 0;
327                 unsigned long k;
328
329                 /* Paint a few lines before the first interesting line. */
330                 while (j < i)
331                         sline[j++].flag |= mark | no_pre_delete;
332
333         again:
334                 /* we know up to i is to be included.  where does the
335                  * next uninteresting one start?
336                  */
337                 j = find_next(sline, mark, i, cnt, 1);
338                 if (cnt < j)
339                         break; /* the rest are all interesting */
340
341                 /* lookahead context lines */
342                 k = find_next(sline, mark, j, cnt, 0);
343                 j = adjust_hunk_tail(sline, all_mask, i, j);
344
345                 if (k < j + context) {
346                         /* k is interesting and [j,k) are not, but
347                          * paint them interesting because the gap is small.
348                          */
349                         while (j < k)
350                                 sline[j++].flag |= mark;
351                         i = k;
352                         goto again;
353                 }
354
355                 /* j is the first uninteresting line and there is
356                  * no overlap beyond it within context lines.  Paint
357                  * the trailing edge a bit.
358                  */
359                 i = k;
360                 k = (j + context < cnt+1) ? j + context : cnt+1;
361                 while (j < k)
362                         sline[j++].flag |= mark;
363         }
364         return 1;
365 }
366
367 static int make_hunks(struct sline *sline, unsigned long cnt,
368                        int num_parent, int dense)
369 {
370         unsigned long all_mask = (1UL<<num_parent) - 1;
371         unsigned long mark = (1UL<<num_parent);
372         unsigned long i;
373         int has_interesting = 0;
374
375         for (i = 0; i <= cnt; i++) {
376                 if (interesting(&sline[i], all_mask))
377                         sline[i].flag |= mark;
378                 else
379                         sline[i].flag &= ~mark;
380         }
381         if (!dense)
382                 return give_context(sline, cnt, num_parent);
383
384         /* Look at each hunk, and if we have changes from only one
385          * parent, or the changes are the same from all but one
386          * parent, mark that uninteresting.
387          */
388         i = 0;
389         while (i <= cnt) {
390                 unsigned long j, hunk_begin, hunk_end;
391                 unsigned long same_diff;
392                 while (i <= cnt && !(sline[i].flag & mark))
393                         i++;
394                 if (cnt < i)
395                         break; /* No more interesting hunks */
396                 hunk_begin = i;
397                 for (j = i + 1; j <= cnt; j++) {
398                         if (!(sline[j].flag & mark)) {
399                                 /* Look beyond the end to see if there
400                                  * is an interesting line after this
401                                  * hunk within context span.
402                                  */
403                                 unsigned long la; /* lookahead */
404                                 int contin = 0;
405                                 la = adjust_hunk_tail(sline, all_mask,
406                                                      hunk_begin, j);
407                                 la = (la + context < cnt + 1) ?
408                                         (la + context) : cnt + 1;
409                                 while (j <= --la) {
410                                         if (sline[la].flag & mark) {
411                                                 contin = 1;
412                                                 break;
413                                         }
414                                 }
415                                 if (!contin)
416                                         break;
417                                 j = la;
418                         }
419                 }
420                 hunk_end = j;
421
422                 /* [i..hunk_end) are interesting.  Now is it really
423                  * interesting?  We check if there are only two versions
424                  * and the result matches one of them.  That is, we look
425                  * at:
426                  *   (+) line, which records lines added to which parents;
427                  *       this line appears in the result.
428                  *   (-) line, which records from what parents the line
429                  *       was removed; this line does not appear in the result.
430                  * then check the set of parents the result has difference
431                  * from, from all lines.  If there are lines that has
432                  * different set of parents that the result has differences
433                  * from, that means we have more than two versions.
434                  *
435                  * Even when we have only two versions, if the result does
436                  * not match any of the parents, the it should be considered
437                  * interesting.  In such a case, we would have all '+' line.
438                  * After passing the above "two versions" test, that would
439                  * appear as "the same set of parents" to be "all parents".
440                  */
441                 same_diff = 0;
442                 has_interesting = 0;
443                 for (j = i; j < hunk_end && !has_interesting; j++) {
444                         unsigned long this_diff = sline[j].flag & all_mask;
445                         struct lline *ll = sline[j].lost_head;
446                         if (this_diff) {
447                                 /* This has some changes.  Is it the
448                                  * same as others?
449                                  */
450                                 if (!same_diff)
451                                         same_diff = this_diff;
452                                 else if (same_diff != this_diff) {
453                                         has_interesting = 1;
454                                         break;
455                                 }
456                         }
457                         while (ll && !has_interesting) {
458                                 /* Lost this line from these parents;
459                                  * who are they?  Are they the same?
460                                  */
461                                 this_diff = ll->parent_map;
462                                 if (!same_diff)
463                                         same_diff = this_diff;
464                                 else if (same_diff != this_diff) {
465                                         has_interesting = 1;
466                                 }
467                                 ll = ll->next;
468                         }
469                 }
470
471                 if (!has_interesting && same_diff != all_mask) {
472                         /* This hunk is not that interesting after all */
473                         for (j = hunk_begin; j < hunk_end; j++)
474                                 sline[j].flag &= ~mark;
475                 }
476                 i = hunk_end;
477         }
478
479         has_interesting = give_context(sline, cnt, num_parent);
480         return has_interesting;
481 }
482
483 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
484 {
485         l0 = sline[l0].p_lno[n];
486         l1 = sline[l1].p_lno[n];
487         printf(" -%lu,%lu", l0, l1-l0-null_context);
488 }
489
490 static int hunk_comment_line(const char *bol)
491 {
492         int ch;
493
494         if (!bol)
495                 return 0;
496         ch = *bol & 0xff;
497         return (isalpha(ch) || ch == '_' || ch == '$');
498 }
499
500 static void show_line_to_eol(const char *line, int len, const char *reset)
501 {
502         int saw_cr_at_eol = 0;
503         if (len < 0)
504                 len = strlen(line);
505         saw_cr_at_eol = (len && line[len-1] == '\r');
506
507         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
508                reset,
509                saw_cr_at_eol ? "\r" : "");
510 }
511
512 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
513                        int use_color)
514 {
515         unsigned long mark = (1UL<<num_parent);
516         unsigned long no_pre_delete = (2UL<<num_parent);
517         int i;
518         unsigned long lno = 0;
519         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
520         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
521         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
522         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
523         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
524
525         if (!cnt)
526                 return; /* result deleted */
527
528         while (1) {
529                 struct sline *sl = &sline[lno];
530                 unsigned long hunk_end;
531                 unsigned long rlines;
532                 const char *hunk_comment = NULL;
533                 unsigned long null_context = 0;
534
535                 while (lno <= cnt && !(sline[lno].flag & mark)) {
536                         if (hunk_comment_line(sline[lno].bol))
537                                 hunk_comment = sline[lno].bol;
538                         lno++;
539                 }
540                 if (cnt < lno)
541                         break;
542                 else {
543                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
544                                 if (!(sline[hunk_end].flag & mark))
545                                         break;
546                 }
547                 rlines = hunk_end - lno;
548                 if (cnt < hunk_end)
549                         rlines--; /* pointing at the last delete hunk */
550
551                 if (!context) {
552                         /*
553                          * Even when running with --unified=0, all
554                          * lines in the hunk needs to be processed in
555                          * the loop below in order to show the
556                          * deletion recorded in lost_head.  However,
557                          * we do not want to show the resulting line
558                          * with all blank context markers in such a
559                          * case.  Compensate.
560                          */
561                         unsigned long j;
562                         for (j = lno; j < hunk_end; j++)
563                                 if (!(sline[j].flag & (mark-1)))
564                                         null_context++;
565                         rlines -= null_context;
566                 }
567
568                 fputs(c_frag, stdout);
569                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
570                 for (i = 0; i < num_parent; i++)
571                         show_parent_lno(sline, lno, hunk_end, i, null_context);
572                 printf(" +%lu,%lu ", lno+1, rlines);
573                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
574
575                 if (hunk_comment) {
576                         int comment_end = 0;
577                         for (i = 0; i < 40; i++) {
578                                 int ch = hunk_comment[i] & 0xff;
579                                 if (!ch || ch == '\n')
580                                         break;
581                                 if (!isspace(ch))
582                                     comment_end = i;
583                         }
584                         if (comment_end)
585                                 putchar(' ');
586                         for (i = 0; i < comment_end; i++)
587                                 putchar(hunk_comment[i]);
588                 }
589
590                 printf("%s\n", c_reset);
591                 while (lno < hunk_end) {
592                         struct lline *ll;
593                         int j;
594                         unsigned long p_mask;
595                         sl = &sline[lno++];
596                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
597                         while (ll) {
598                                 fputs(c_old, stdout);
599                                 for (j = 0; j < num_parent; j++) {
600                                         if (ll->parent_map & (1UL<<j))
601                                                 putchar('-');
602                                         else
603                                                 putchar(' ');
604                                 }
605                                 show_line_to_eol(ll->line, -1, c_reset);
606                                 ll = ll->next;
607                         }
608                         if (cnt < lno)
609                                 break;
610                         p_mask = 1;
611                         if (!(sl->flag & (mark-1))) {
612                                 /*
613                                  * This sline was here to hang the
614                                  * lost lines in front of it.
615                                  */
616                                 if (!context)
617                                         continue;
618                                 fputs(c_plain, stdout);
619                         }
620                         else
621                                 fputs(c_new, stdout);
622                         for (j = 0; j < num_parent; j++) {
623                                 if (p_mask & sl->flag)
624                                         putchar('+');
625                                 else
626                                         putchar(' ');
627                                 p_mask <<= 1;
628                         }
629                         show_line_to_eol(sl->bol, sl->len, c_reset);
630                 }
631         }
632 }
633
634 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
635                                int i, int j)
636 {
637         /* We have already examined parent j and we know parent i
638          * and parent j are the same, so reuse the combined result
639          * of parent j for parent i.
640          */
641         unsigned long lno, imask, jmask;
642         imask = (1UL<<i);
643         jmask = (1UL<<j);
644
645         for (lno = 0; lno <= cnt; lno++) {
646                 struct lline *ll = sline->lost_head;
647                 sline->p_lno[i] = sline->p_lno[j];
648                 while (ll) {
649                         if (ll->parent_map & jmask)
650                                 ll->parent_map |= imask;
651                         ll = ll->next;
652                 }
653                 if (sline->flag & jmask)
654                         sline->flag |= imask;
655                 sline++;
656         }
657         /* the overall size of the file (sline[cnt]) */
658         sline->p_lno[i] = sline->p_lno[j];
659 }
660
661 static void dump_quoted_path(const char *head,
662                              const char *prefix,
663                              const char *path,
664                              const char *c_meta, const char *c_reset)
665 {
666         static struct strbuf buf = STRBUF_INIT;
667
668         strbuf_reset(&buf);
669         strbuf_addstr(&buf, c_meta);
670         strbuf_addstr(&buf, head);
671         quote_two_c_style(&buf, prefix, path, 0);
672         strbuf_addstr(&buf, c_reset);
673         puts(buf.buf);
674 }
675
676 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
677                             int dense, struct rev_info *rev)
678 {
679         struct diff_options *opt = &rev->diffopt;
680         unsigned long result_size, cnt, lno;
681         char *result, *cp;
682         struct sline *sline; /* survived lines */
683         int mode_differs = 0;
684         int i, show_hunks;
685         int working_tree_file = is_null_sha1(elem->sha1);
686         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
687         const char *a_prefix, *b_prefix;
688         mmfile_t result_file;
689
690         context = opt->context;
691         a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
692         b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
693
694         /* Read the result of merge first */
695         if (!working_tree_file)
696                 result = grab_blob(elem->sha1, &result_size);
697         else {
698                 /* Used by diff-tree to read from the working tree */
699                 struct stat st;
700                 int fd = -1;
701
702                 if (lstat(elem->path, &st) < 0)
703                         goto deleted_file;
704
705                 if (S_ISLNK(st.st_mode)) {
706                         size_t len = xsize_t(st.st_size);
707                         result_size = len;
708                         result = xmalloc(len + 1);
709                         if (result_size != readlink(elem->path, result, len)) {
710                                 error("readlink(%s): %s", elem->path,
711                                       strerror(errno));
712                                 return;
713                         }
714                         result[len] = 0;
715                         elem->mode = canon_mode(st.st_mode);
716                 }
717                 else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
718                          !fstat(fd, &st)) {
719                         size_t len = xsize_t(st.st_size);
720                         ssize_t done;
721                         int is_file, i;
722
723                         elem->mode = canon_mode(st.st_mode);
724                         /* if symlinks don't work, assume symlink if all parents
725                          * are symlinks
726                          */
727                         is_file = has_symlinks;
728                         for (i = 0; !is_file && i < num_parent; i++)
729                                 is_file = !S_ISLNK(elem->parent[i].mode);
730                         if (!is_file)
731                                 elem->mode = canon_mode(S_IFLNK);
732
733                         result_size = len;
734                         result = xmalloc(len + 1);
735
736                         done = read_in_full(fd, result, len);
737                         if (done < 0)
738                                 die("read error '%s'", elem->path);
739                         else if (done < len)
740                                 die("early EOF '%s'", elem->path);
741
742                         result[len] = 0;
743
744                         /* If not a fake symlink, apply filters, e.g. autocrlf */
745                         if (is_file) {
746                                 struct strbuf buf = STRBUF_INIT;
747
748                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
749                                         free(result);
750                                         result = strbuf_detach(&buf, &len);
751                                         result_size = len;
752                                 }
753                         }
754                 }
755                 else {
756                 deleted_file:
757                         result_size = 0;
758                         elem->mode = 0;
759                         result = xcalloc(1, 1);
760                 }
761
762                 if (0 <= fd)
763                         close(fd);
764         }
765
766         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
767                 if (*cp == '\n')
768                         cnt++;
769         }
770         if (result_size && result[result_size-1] != '\n')
771                 cnt++; /* incomplete line */
772
773         sline = xcalloc(cnt+2, sizeof(*sline));
774         sline[0].bol = result;
775         for (lno = 0; lno <= cnt + 1; lno++) {
776                 sline[lno].lost_tail = &sline[lno].lost_head;
777                 sline[lno].flag = 0;
778         }
779         for (lno = 0, cp = result; cp < result + result_size; cp++) {
780                 if (*cp == '\n') {
781                         sline[lno].len = cp - sline[lno].bol;
782                         lno++;
783                         if (lno < cnt)
784                                 sline[lno].bol = cp + 1;
785                 }
786         }
787         if (result_size && result[result_size-1] != '\n')
788                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
789
790         result_file.ptr = result;
791         result_file.size = result_size;
792
793         /* Even p_lno[cnt+1] is valid -- that is for the end line number
794          * for deletion hunk at the end.
795          */
796         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
797         for (lno = 0; lno <= cnt; lno++)
798                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
799
800         for (i = 0; i < num_parent; i++) {
801                 int j;
802                 for (j = 0; j < i; j++) {
803                         if (!hashcmp(elem->parent[i].sha1,
804                                      elem->parent[j].sha1)) {
805                                 reuse_combine_diff(sline, cnt, i, j);
806                                 break;
807                         }
808                 }
809                 if (i <= j)
810                         combine_diff(elem->parent[i].sha1, &result_file, sline,
811                                      cnt, i, num_parent);
812                 if (elem->parent[i].mode != elem->mode)
813                         mode_differs = 1;
814         }
815
816         show_hunks = make_hunks(sline, cnt, num_parent, dense);
817
818         if (show_hunks || mode_differs || working_tree_file) {
819                 const char *abb;
820                 int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
821                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
822                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
823                 int added = 0;
824                 int deleted = 0;
825
826                 if (rev->loginfo && !rev->no_commit_id)
827                         show_log(rev);
828                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
829                                  "", elem->path, c_meta, c_reset);
830                 printf("%sindex ", c_meta);
831                 for (i = 0; i < num_parent; i++) {
832                         abb = find_unique_abbrev(elem->parent[i].sha1,
833                                                  abbrev);
834                         printf("%s%s", i ? "," : "", abb);
835                 }
836                 abb = find_unique_abbrev(elem->sha1, abbrev);
837                 printf("..%s%s\n", abb, c_reset);
838
839                 if (mode_differs) {
840                         deleted = !elem->mode;
841
842                         /* We say it was added if nobody had it */
843                         added = !deleted;
844                         for (i = 0; added && i < num_parent; i++)
845                                 if (elem->parent[i].status !=
846                                     DIFF_STATUS_ADDED)
847                                         added = 0;
848                         if (added)
849                                 printf("%snew file mode %06o",
850                                        c_meta, elem->mode);
851                         else {
852                                 if (deleted)
853                                         printf("%sdeleted file ", c_meta);
854                                 printf("mode ");
855                                 for (i = 0; i < num_parent; i++) {
856                                         printf("%s%06o", i ? "," : "",
857                                                elem->parent[i].mode);
858                                 }
859                                 if (elem->mode)
860                                         printf("..%06o", elem->mode);
861                         }
862                         printf("%s\n", c_reset);
863                 }
864                 if (added)
865                         dump_quoted_path("--- ", "", "/dev/null",
866                                          c_meta, c_reset);
867                 else
868                         dump_quoted_path("--- ", a_prefix, elem->path,
869                                          c_meta, c_reset);
870                 if (deleted)
871                         dump_quoted_path("+++ ", "", "/dev/null",
872                                          c_meta, c_reset);
873                 else
874                         dump_quoted_path("+++ ", b_prefix, elem->path,
875                                          c_meta, c_reset);
876                 dump_sline(sline, cnt, num_parent,
877                            DIFF_OPT_TST(opt, COLOR_DIFF));
878         }
879         free(result);
880
881         for (lno = 0; lno < cnt; lno++) {
882                 if (sline[lno].lost_head) {
883                         struct lline *ll = sline[lno].lost_head;
884                         while (ll) {
885                                 struct lline *tmp = ll;
886                                 ll = ll->next;
887                                 free(tmp);
888                         }
889                 }
890         }
891         free(sline[0].p_lno);
892         free(sline);
893 }
894
895 #define COLONS "::::::::::::::::::::::::::::::::"
896
897 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
898 {
899         struct diff_options *opt = &rev->diffopt;
900         int i, offset;
901         const char *prefix;
902         int line_termination, inter_name_termination;
903
904         line_termination = opt->line_termination;
905         inter_name_termination = '\t';
906         if (!line_termination)
907                 inter_name_termination = 0;
908
909         if (rev->loginfo && !rev->no_commit_id)
910                 show_log(rev);
911
912         if (opt->output_format & DIFF_FORMAT_RAW) {
913                 offset = strlen(COLONS) - num_parent;
914                 if (offset < 0)
915                         offset = 0;
916                 prefix = COLONS + offset;
917
918                 /* Show the modes */
919                 for (i = 0; i < num_parent; i++) {
920                         printf("%s%06o", prefix, p->parent[i].mode);
921                         prefix = " ";
922                 }
923                 printf("%s%06o", prefix, p->mode);
924
925                 /* Show sha1's */
926                 for (i = 0; i < num_parent; i++)
927                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
928                                                          opt->abbrev));
929                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
930         }
931
932         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
933                 for (i = 0; i < num_parent; i++)
934                         putchar(p->parent[i].status);
935                 putchar(inter_name_termination);
936         }
937
938         write_name_quoted(p->path, stdout, line_termination);
939 }
940
941 void show_combined_diff(struct combine_diff_path *p,
942                        int num_parent,
943                        int dense,
944                        struct rev_info *rev)
945 {
946         struct diff_options *opt = &rev->diffopt;
947         if (!p->len)
948                 return;
949         if (opt->output_format & (DIFF_FORMAT_RAW |
950                                   DIFF_FORMAT_NAME |
951                                   DIFF_FORMAT_NAME_STATUS))
952                 show_raw_diff(p, num_parent, rev);
953         else if (opt->output_format & DIFF_FORMAT_PATCH)
954                 show_patch_diff(p, num_parent, dense, rev);
955 }
956
957 void diff_tree_combined(const unsigned char *sha1,
958                         const unsigned char parent[][20],
959                         int num_parent,
960                         int dense,
961                         struct rev_info *rev)
962 {
963         struct diff_options *opt = &rev->diffopt;
964         struct diff_options diffopts;
965         struct combine_diff_path *p, *paths = NULL;
966         int i, num_paths, needsep, show_log_first;
967
968         diffopts = *opt;
969         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
970         DIFF_OPT_SET(&diffopts, RECURSIVE);
971         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
972
973         show_log_first = !!rev->loginfo && !rev->no_commit_id;
974         needsep = 0;
975         /* find set of paths that everybody touches */
976         for (i = 0; i < num_parent; i++) {
977                 /* show stat against the first parent even
978                  * when doing combined diff.
979                  */
980                 int stat_opt = (opt->output_format &
981                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
982                 if (i == 0 && stat_opt)
983                         diffopts.output_format = stat_opt;
984                 else
985                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
986                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
987                 diffcore_std(&diffopts);
988                 paths = intersect_paths(paths, i, num_parent);
989
990                 if (show_log_first && i == 0) {
991                         show_log(rev);
992                         if (rev->verbose_header && opt->output_format)
993                                 putchar(opt->line_termination);
994                 }
995                 diff_flush(&diffopts);
996         }
997
998         /* find out surviving paths */
999         for (num_paths = 0, p = paths; p; p = p->next) {
1000                 if (p->len)
1001                         num_paths++;
1002         }
1003         if (num_paths) {
1004                 if (opt->output_format & (DIFF_FORMAT_RAW |
1005                                           DIFF_FORMAT_NAME |
1006                                           DIFF_FORMAT_NAME_STATUS)) {
1007                         for (p = paths; p; p = p->next) {
1008                                 if (p->len)
1009                                         show_raw_diff(p, num_parent, rev);
1010                         }
1011                         needsep = 1;
1012                 }
1013                 else if (opt->output_format &
1014                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1015                         needsep = 1;
1016                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1017                         if (needsep)
1018                                 putchar(opt->line_termination);
1019                         for (p = paths; p; p = p->next) {
1020                                 if (p->len)
1021                                         show_patch_diff(p, num_parent, dense,
1022                                                         rev);
1023                         }
1024                 }
1025         }
1026
1027         /* Clean things up */
1028         while (paths) {
1029                 struct combine_diff_path *tmp = paths;
1030                 paths = paths->next;
1031                 free(tmp);
1032         }
1033 }
1034
1035 void diff_tree_combined_merge(const unsigned char *sha1,
1036                              int dense, struct rev_info *rev)
1037 {
1038         int num_parent;
1039         const unsigned char (*parent)[20];
1040         struct commit *commit = lookup_commit(sha1);
1041         struct commit_list *parents;
1042
1043         /* count parents */
1044         for (parents = commit->parents, num_parent = 0;
1045              parents;
1046              parents = parents->next, num_parent++)
1047                 ; /* nothing */
1048
1049         parent = xmalloc(num_parent * sizeof(*parent));
1050         for (parents = commit->parents, num_parent = 0;
1051              parents;
1052              parents = parents->next, num_parent++)
1053                 hashcpy((unsigned char*)(parent + num_parent),
1054                         parents->item->object.sha1);
1055         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1056 }