contrib/git-credential-gnome-keyring.c: remove unnecessary pre-declarations
[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 "xdiff/xmacros.h"
9 #include "log-tree.h"
10 #include "refs.h"
11 #include "userdiff.h"
12 #include "sha1-array.h"
13 #include "revision.h"
14
15 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
16 {
17         struct diff_queue_struct *q = &diff_queued_diff;
18         struct combine_diff_path *p;
19         int i;
20
21         if (!n) {
22                 struct combine_diff_path *list = NULL, **tail = &list;
23                 for (i = 0; i < q->nr; i++) {
24                         int len;
25                         const char *path;
26                         if (diff_unmodified_pair(q->queue[i]))
27                                 continue;
28                         path = q->queue[i]->two->path;
29                         len = strlen(path);
30                         p = xmalloc(combine_diff_path_size(num_parent, len));
31                         p->path = (char *) &(p->parent[num_parent]);
32                         memcpy(p->path, path, len);
33                         p->path[len] = 0;
34                         p->len = len;
35                         p->next = NULL;
36                         memset(p->parent, 0,
37                                sizeof(p->parent[0]) * num_parent);
38
39                         hashcpy(p->sha1, q->queue[i]->two->sha1);
40                         p->mode = q->queue[i]->two->mode;
41                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
42                         p->parent[n].mode = q->queue[i]->one->mode;
43                         p->parent[n].status = q->queue[i]->status;
44                         *tail = p;
45                         tail = &p->next;
46                 }
47                 return list;
48         }
49
50         for (p = curr; p; p = p->next) {
51                 int found = 0;
52                 if (!p->len)
53                         continue;
54                 for (i = 0; i < q->nr; i++) {
55                         const char *path;
56                         int len;
57
58                         if (diff_unmodified_pair(q->queue[i]))
59                                 continue;
60                         path = q->queue[i]->two->path;
61                         len = strlen(path);
62                         if (len == p->len && !memcmp(path, p->path, len)) {
63                                 found = 1;
64                                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
65                                 p->parent[n].mode = q->queue[i]->one->mode;
66                                 p->parent[n].status = q->queue[i]->status;
67                                 break;
68                         }
69                 }
70                 if (!found)
71                         p->len = 0;
72         }
73         return curr;
74 }
75
76 /* Lines lost from parent */
77 struct lline {
78         struct lline *next, *prev;
79         int len;
80         unsigned long parent_map;
81         char line[FLEX_ARRAY];
82 };
83
84 /* Lines lost from current parent (before coalescing) */
85 struct plost {
86         struct lline *lost_head, *lost_tail;
87         int len;
88 };
89
90 /* Lines surviving in the merge result */
91 struct sline {
92         /* Accumulated and coalesced lost lines */
93         struct lline *lost;
94         int lenlost;
95         struct plost plost;
96         char *bol;
97         int len;
98         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
99          * we did not change it).
100          * bit N is used for "interesting" lines, including context.
101          * bit (N+1) is used for "do not show deletion before this".
102          */
103         unsigned long flag;
104         unsigned long *p_lno;
105 };
106
107 static int match_string_spaces(const char *line1, int len1,
108                                const char *line2, int len2,
109                                long flags)
110 {
111         if (flags & XDF_WHITESPACE_FLAGS) {
112                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
113                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
114         }
115
116         if (!(flags & (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE)))
117                 return (len1 == len2 && !memcmp(line1, line2, len1));
118
119         while (len1 > 0 && len2 > 0) {
120                 len1--;
121                 len2--;
122                 if (XDL_ISSPACE(line1[len1]) || XDL_ISSPACE(line2[len2])) {
123                         if ((flags & XDF_IGNORE_WHITESPACE_CHANGE) &&
124                             (!XDL_ISSPACE(line1[len1]) || !XDL_ISSPACE(line2[len2])))
125                                 return 0;
126
127                         for (; len1 > 0 && XDL_ISSPACE(line1[len1]); len1--);
128                         for (; len2 > 0 && XDL_ISSPACE(line2[len2]); len2--);
129                 }
130                 if (line1[len1] != line2[len2])
131                         return 0;
132         }
133
134         if (flags & XDF_IGNORE_WHITESPACE) {
135                 /* Consume remaining spaces */
136                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
137                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
138         }
139
140         /* We matched full line1 and line2 */
141         if (!len1 && !len2)
142                 return 1;
143
144         return 0;
145 }
146
147 enum coalesce_direction { MATCH, BASE, NEW };
148
149 /* Coalesce new lines into base by finding LCS */
150 static struct lline *coalesce_lines(struct lline *base, int *lenbase,
151                                     struct lline *new, int lennew,
152                                     unsigned long parent, long flags)
153 {
154         int **lcs;
155         enum coalesce_direction **directions;
156         struct lline *baseend, *newend = NULL;
157         int i, j, origbaselen = *lenbase;
158
159         if (new == NULL)
160                 return base;
161
162         if (base == NULL) {
163                 *lenbase = lennew;
164                 return new;
165         }
166
167         /*
168          * Coalesce new lines into base by finding the LCS
169          * - Create the table to run dynamic programming
170          * - Compute the LCS
171          * - Then reverse read the direction structure:
172          *   - If we have MATCH, assign parent to base flag, and consume
173          *   both baseend and newend
174          *   - Else if we have BASE, consume baseend
175          *   - Else if we have NEW, insert newend lline into base and
176          *   consume newend
177          */
178         lcs = xcalloc(origbaselen + 1, sizeof(int*));
179         directions = xcalloc(origbaselen + 1, sizeof(enum coalesce_direction*));
180         for (i = 0; i < origbaselen + 1; i++) {
181                 lcs[i] = xcalloc(lennew + 1, sizeof(int));
182                 directions[i] = xcalloc(lennew + 1, sizeof(enum coalesce_direction));
183                 directions[i][0] = BASE;
184         }
185         for (j = 1; j < lennew + 1; j++)
186                 directions[0][j] = NEW;
187
188         for (i = 1, baseend = base; i < origbaselen + 1; i++) {
189                 for (j = 1, newend = new; j < lennew + 1; j++) {
190                         if (match_string_spaces(baseend->line, baseend->len,
191                                                 newend->line, newend->len, flags)) {
192                                 lcs[i][j] = lcs[i - 1][j - 1] + 1;
193                                 directions[i][j] = MATCH;
194                         } else if (lcs[i][j - 1] >= lcs[i - 1][j]) {
195                                 lcs[i][j] = lcs[i][j - 1];
196                                 directions[i][j] = NEW;
197                         } else {
198                                 lcs[i][j] = lcs[i - 1][j];
199                                 directions[i][j] = BASE;
200                         }
201                         if (newend->next)
202                                 newend = newend->next;
203                 }
204                 if (baseend->next)
205                         baseend = baseend->next;
206         }
207
208         for (i = 0; i < origbaselen + 1; i++)
209                 free(lcs[i]);
210         free(lcs);
211
212         /* At this point, baseend and newend point to the end of each lists */
213         i--;
214         j--;
215         while (i != 0 || j != 0) {
216                 if (directions[i][j] == MATCH) {
217                         baseend->parent_map |= 1<<parent;
218                         baseend = baseend->prev;
219                         newend = newend->prev;
220                         i--;
221                         j--;
222                 } else if (directions[i][j] == NEW) {
223                         struct lline *lline;
224
225                         lline = newend;
226                         /* Remove lline from new list and update newend */
227                         if (lline->prev)
228                                 lline->prev->next = lline->next;
229                         else
230                                 new = lline->next;
231                         if (lline->next)
232                                 lline->next->prev = lline->prev;
233
234                         newend = lline->prev;
235                         j--;
236
237                         /* Add lline to base list */
238                         if (baseend) {
239                                 lline->next = baseend->next;
240                                 lline->prev = baseend;
241                                 if (lline->prev)
242                                         lline->prev->next = lline;
243                         }
244                         else {
245                                 lline->next = base;
246                                 base = lline;
247                         }
248                         (*lenbase)++;
249
250                         if (lline->next)
251                                 lline->next->prev = lline;
252
253                 } else {
254                         baseend = baseend->prev;
255                         i--;
256                 }
257         }
258
259         newend = new;
260         while (newend) {
261                 struct lline *lline = newend;
262                 newend = newend->next;
263                 free(lline);
264         }
265
266         for (i = 0; i < origbaselen + 1; i++)
267                 free(directions[i]);
268         free(directions);
269
270         return base;
271 }
272
273 static char *grab_blob(const unsigned char *sha1, unsigned int mode,
274                        unsigned long *size, struct userdiff_driver *textconv,
275                        const char *path)
276 {
277         char *blob;
278         enum object_type type;
279
280         if (S_ISGITLINK(mode)) {
281                 blob = xmalloc(100);
282                 *size = snprintf(blob, 100,
283                                  "Subproject commit %s\n", sha1_to_hex(sha1));
284         } else if (is_null_sha1(sha1)) {
285                 /* deleted blob */
286                 *size = 0;
287                 return xcalloc(1, 1);
288         } else if (textconv) {
289                 struct diff_filespec *df = alloc_filespec(path);
290                 fill_filespec(df, sha1, 1, mode);
291                 *size = fill_textconv(textconv, df, &blob);
292                 free_filespec(df);
293         } else {
294                 blob = read_sha1_file(sha1, &type, size);
295                 if (type != OBJ_BLOB)
296                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
297         }
298         return blob;
299 }
300
301 static void append_lost(struct sline *sline, int n, const char *line, int len)
302 {
303         struct lline *lline;
304         unsigned long this_mask = (1UL<<n);
305         if (line[len-1] == '\n')
306                 len--;
307
308         lline = xmalloc(sizeof(*lline) + len + 1);
309         lline->len = len;
310         lline->next = NULL;
311         lline->prev = sline->plost.lost_tail;
312         if (lline->prev)
313                 lline->prev->next = lline;
314         else
315                 sline->plost.lost_head = lline;
316         sline->plost.lost_tail = lline;
317         sline->plost.len++;
318         lline->parent_map = this_mask;
319         memcpy(lline->line, line, len);
320         lline->line[len] = 0;
321 }
322
323 struct combine_diff_state {
324         unsigned int lno;
325         int ob, on, nb, nn;
326         unsigned long nmask;
327         int num_parent;
328         int n;
329         struct sline *sline;
330         struct sline *lost_bucket;
331 };
332
333 static void consume_line(void *state_, char *line, unsigned long len)
334 {
335         struct combine_diff_state *state = state_;
336         if (5 < len && !memcmp("@@ -", line, 4)) {
337                 if (parse_hunk_header(line, len,
338                                       &state->ob, &state->on,
339                                       &state->nb, &state->nn))
340                         return;
341                 state->lno = state->nb;
342                 if (state->nn == 0) {
343                         /* @@ -X,Y +N,0 @@ removed Y lines
344                          * that would have come *after* line N
345                          * in the result.  Our lost buckets hang
346                          * to the line after the removed lines,
347                          *
348                          * Note that this is correct even when N == 0,
349                          * in which case the hunk removes the first
350                          * line in the file.
351                          */
352                         state->lost_bucket = &state->sline[state->nb];
353                         if (!state->nb)
354                                 state->nb = 1;
355                 } else {
356                         state->lost_bucket = &state->sline[state->nb-1];
357                 }
358                 if (!state->sline[state->nb-1].p_lno)
359                         state->sline[state->nb-1].p_lno =
360                                 xcalloc(state->num_parent,
361                                         sizeof(unsigned long));
362                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
363                 return;
364         }
365         if (!state->lost_bucket)
366                 return; /* not in any hunk yet */
367         switch (line[0]) {
368         case '-':
369                 append_lost(state->lost_bucket, state->n, line+1, len-1);
370                 break;
371         case '+':
372                 state->sline[state->lno-1].flag |= state->nmask;
373                 state->lno++;
374                 break;
375         }
376 }
377
378 static void combine_diff(const unsigned char *parent, unsigned int mode,
379                          mmfile_t *result_file,
380                          struct sline *sline, unsigned int cnt, int n,
381                          int num_parent, int result_deleted,
382                          struct userdiff_driver *textconv,
383                          const char *path, long flags)
384 {
385         unsigned int p_lno, lno;
386         unsigned long nmask = (1UL << n);
387         xpparam_t xpp;
388         xdemitconf_t xecfg;
389         mmfile_t parent_file;
390         struct combine_diff_state state;
391         unsigned long sz;
392
393         if (result_deleted)
394                 return; /* result deleted */
395
396         parent_file.ptr = grab_blob(parent, mode, &sz, textconv, path);
397         parent_file.size = sz;
398         memset(&xpp, 0, sizeof(xpp));
399         xpp.flags = flags;
400         memset(&xecfg, 0, sizeof(xecfg));
401         memset(&state, 0, sizeof(state));
402         state.nmask = nmask;
403         state.sline = sline;
404         state.lno = 1;
405         state.num_parent = num_parent;
406         state.n = n;
407
408         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
409                       &xpp, &xecfg);
410         free(parent_file.ptr);
411
412         /* Assign line numbers for this parent.
413          *
414          * sline[lno].p_lno[n] records the first line number
415          * (counting from 1) for parent N if the final hunk display
416          * started by showing sline[lno] (possibly showing the lost
417          * lines attached to it first).
418          */
419         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
420                 struct lline *ll;
421                 sline[lno].p_lno[n] = p_lno;
422
423                 /* Coalesce new lines */
424                 if (sline[lno].plost.lost_head) {
425                         struct sline *sl = &sline[lno];
426                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
427                                                   sl->plost.lost_head,
428                                                   sl->plost.len, n, flags);
429                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
430                         sl->plost.len = 0;
431                 }
432
433                 /* How many lines would this sline advance the p_lno? */
434                 ll = sline[lno].lost;
435                 while (ll) {
436                         if (ll->parent_map & nmask)
437                                 p_lno++; /* '-' means parent had it */
438                         ll = ll->next;
439                 }
440                 if (lno < cnt && !(sline[lno].flag & nmask))
441                         p_lno++; /* no '+' means parent had it */
442         }
443         sline[lno].p_lno[n] = p_lno; /* trailer */
444 }
445
446 static unsigned long context = 3;
447 static char combine_marker = '@';
448
449 static int interesting(struct sline *sline, unsigned long all_mask)
450 {
451         /* If some parents lost lines here, or if we have added to
452          * some parent, it is interesting.
453          */
454         return ((sline->flag & all_mask) || sline->lost);
455 }
456
457 static unsigned long adjust_hunk_tail(struct sline *sline,
458                                       unsigned long all_mask,
459                                       unsigned long hunk_begin,
460                                       unsigned long i)
461 {
462         /* i points at the first uninteresting line.  If the last line
463          * of the hunk was interesting only because it has some
464          * deletion, then it is not all that interesting for the
465          * purpose of giving trailing context lines.  This is because
466          * we output '-' line and then unmodified sline[i-1] itself in
467          * that case which gives us one extra context line.
468          */
469         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
470                 i--;
471         return i;
472 }
473
474 static unsigned long find_next(struct sline *sline,
475                                unsigned long mark,
476                                unsigned long i,
477                                unsigned long cnt,
478                                int look_for_uninteresting)
479 {
480         /* We have examined up to i-1 and are about to look at i.
481          * Find next interesting or uninteresting line.  Here,
482          * "interesting" does not mean interesting(), but marked by
483          * the give_context() function below (i.e. it includes context
484          * lines that are not interesting to interesting() function
485          * that are surrounded by interesting() ones.
486          */
487         while (i <= cnt)
488                 if (look_for_uninteresting
489                     ? !(sline[i].flag & mark)
490                     : (sline[i].flag & mark))
491                         return i;
492                 else
493                         i++;
494         return i;
495 }
496
497 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
498 {
499         unsigned long all_mask = (1UL<<num_parent) - 1;
500         unsigned long mark = (1UL<<num_parent);
501         unsigned long no_pre_delete = (2UL<<num_parent);
502         unsigned long i;
503
504         /* Two groups of interesting lines may have a short gap of
505          * uninteresting lines.  Connect such groups to give them a
506          * bit of context.
507          *
508          * We first start from what the interesting() function says,
509          * and mark them with "mark", and paint context lines with the
510          * mark.  So interesting() would still say false for such context
511          * lines but they are treated as "interesting" in the end.
512          */
513         i = find_next(sline, mark, 0, cnt, 0);
514         if (cnt < i)
515                 return 0;
516
517         while (i <= cnt) {
518                 unsigned long j = (context < i) ? (i - context) : 0;
519                 unsigned long k;
520
521                 /* Paint a few lines before the first interesting line. */
522                 while (j < i) {
523                         if (!(sline[j].flag & mark))
524                                 sline[j].flag |= no_pre_delete;
525                         sline[j++].flag |= mark;
526                 }
527
528         again:
529                 /* we know up to i is to be included.  where does the
530                  * next uninteresting one start?
531                  */
532                 j = find_next(sline, mark, i, cnt, 1);
533                 if (cnt < j)
534                         break; /* the rest are all interesting */
535
536                 /* lookahead context lines */
537                 k = find_next(sline, mark, j, cnt, 0);
538                 j = adjust_hunk_tail(sline, all_mask, i, j);
539
540                 if (k < j + context) {
541                         /* k is interesting and [j,k) are not, but
542                          * paint them interesting because the gap is small.
543                          */
544                         while (j < k)
545                                 sline[j++].flag |= mark;
546                         i = k;
547                         goto again;
548                 }
549
550                 /* j is the first uninteresting line and there is
551                  * no overlap beyond it within context lines.  Paint
552                  * the trailing edge a bit.
553                  */
554                 i = k;
555                 k = (j + context < cnt+1) ? j + context : cnt+1;
556                 while (j < k)
557                         sline[j++].flag |= mark;
558         }
559         return 1;
560 }
561
562 static int make_hunks(struct sline *sline, unsigned long cnt,
563                        int num_parent, int dense)
564 {
565         unsigned long all_mask = (1UL<<num_parent) - 1;
566         unsigned long mark = (1UL<<num_parent);
567         unsigned long i;
568         int has_interesting = 0;
569
570         for (i = 0; i <= cnt; i++) {
571                 if (interesting(&sline[i], all_mask))
572                         sline[i].flag |= mark;
573                 else
574                         sline[i].flag &= ~mark;
575         }
576         if (!dense)
577                 return give_context(sline, cnt, num_parent);
578
579         /* Look at each hunk, and if we have changes from only one
580          * parent, or the changes are the same from all but one
581          * parent, mark that uninteresting.
582          */
583         i = 0;
584         while (i <= cnt) {
585                 unsigned long j, hunk_begin, hunk_end;
586                 unsigned long same_diff;
587                 while (i <= cnt && !(sline[i].flag & mark))
588                         i++;
589                 if (cnt < i)
590                         break; /* No more interesting hunks */
591                 hunk_begin = i;
592                 for (j = i + 1; j <= cnt; j++) {
593                         if (!(sline[j].flag & mark)) {
594                                 /* Look beyond the end to see if there
595                                  * is an interesting line after this
596                                  * hunk within context span.
597                                  */
598                                 unsigned long la; /* lookahead */
599                                 int contin = 0;
600                                 la = adjust_hunk_tail(sline, all_mask,
601                                                      hunk_begin, j);
602                                 la = (la + context < cnt + 1) ?
603                                         (la + context) : cnt + 1;
604                                 while (la && j <= --la) {
605                                         if (sline[la].flag & mark) {
606                                                 contin = 1;
607                                                 break;
608                                         }
609                                 }
610                                 if (!contin)
611                                         break;
612                                 j = la;
613                         }
614                 }
615                 hunk_end = j;
616
617                 /* [i..hunk_end) are interesting.  Now is it really
618                  * interesting?  We check if there are only two versions
619                  * and the result matches one of them.  That is, we look
620                  * at:
621                  *   (+) line, which records lines added to which parents;
622                  *       this line appears in the result.
623                  *   (-) line, which records from what parents the line
624                  *       was removed; this line does not appear in the result.
625                  * then check the set of parents the result has difference
626                  * from, from all lines.  If there are lines that has
627                  * different set of parents that the result has differences
628                  * from, that means we have more than two versions.
629                  *
630                  * Even when we have only two versions, if the result does
631                  * not match any of the parents, the it should be considered
632                  * interesting.  In such a case, we would have all '+' line.
633                  * After passing the above "two versions" test, that would
634                  * appear as "the same set of parents" to be "all parents".
635                  */
636                 same_diff = 0;
637                 has_interesting = 0;
638                 for (j = i; j < hunk_end && !has_interesting; j++) {
639                         unsigned long this_diff = sline[j].flag & all_mask;
640                         struct lline *ll = sline[j].lost;
641                         if (this_diff) {
642                                 /* This has some changes.  Is it the
643                                  * same as others?
644                                  */
645                                 if (!same_diff)
646                                         same_diff = this_diff;
647                                 else if (same_diff != this_diff) {
648                                         has_interesting = 1;
649                                         break;
650                                 }
651                         }
652                         while (ll && !has_interesting) {
653                                 /* Lost this line from these parents;
654                                  * who are they?  Are they the same?
655                                  */
656                                 this_diff = ll->parent_map;
657                                 if (!same_diff)
658                                         same_diff = this_diff;
659                                 else if (same_diff != this_diff) {
660                                         has_interesting = 1;
661                                 }
662                                 ll = ll->next;
663                         }
664                 }
665
666                 if (!has_interesting && same_diff != all_mask) {
667                         /* This hunk is not that interesting after all */
668                         for (j = hunk_begin; j < hunk_end; j++)
669                                 sline[j].flag &= ~mark;
670                 }
671                 i = hunk_end;
672         }
673
674         has_interesting = give_context(sline, cnt, num_parent);
675         return has_interesting;
676 }
677
678 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
679 {
680         l0 = sline[l0].p_lno[n];
681         l1 = sline[l1].p_lno[n];
682         printf(" -%lu,%lu", l0, l1-l0-null_context);
683 }
684
685 static int hunk_comment_line(const char *bol)
686 {
687         int ch;
688
689         if (!bol)
690                 return 0;
691         ch = *bol & 0xff;
692         return (isalpha(ch) || ch == '_' || ch == '$');
693 }
694
695 static void show_line_to_eol(const char *line, int len, const char *reset)
696 {
697         int saw_cr_at_eol = 0;
698         if (len < 0)
699                 len = strlen(line);
700         saw_cr_at_eol = (len && line[len-1] == '\r');
701
702         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
703                reset,
704                saw_cr_at_eol ? "\r" : "");
705 }
706
707 static void dump_sline(struct sline *sline, const char *line_prefix,
708                        unsigned long cnt, int num_parent,
709                        int use_color, int result_deleted)
710 {
711         unsigned long mark = (1UL<<num_parent);
712         unsigned long no_pre_delete = (2UL<<num_parent);
713         int i;
714         unsigned long lno = 0;
715         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
716         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
717         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
718         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
719         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
720         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
721
722         if (result_deleted)
723                 return; /* result deleted */
724
725         while (1) {
726                 unsigned long hunk_end;
727                 unsigned long rlines;
728                 const char *hunk_comment = NULL;
729                 unsigned long null_context = 0;
730
731                 while (lno <= cnt && !(sline[lno].flag & mark)) {
732                         if (hunk_comment_line(sline[lno].bol))
733                                 hunk_comment = sline[lno].bol;
734                         lno++;
735                 }
736                 if (cnt < lno)
737                         break;
738                 else {
739                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
740                                 if (!(sline[hunk_end].flag & mark))
741                                         break;
742                 }
743                 rlines = hunk_end - lno;
744                 if (cnt < hunk_end)
745                         rlines--; /* pointing at the last delete hunk */
746
747                 if (!context) {
748                         /*
749                          * Even when running with --unified=0, all
750                          * lines in the hunk needs to be processed in
751                          * the loop below in order to show the
752                          * deletion recorded in lost_head.  However,
753                          * we do not want to show the resulting line
754                          * with all blank context markers in such a
755                          * case.  Compensate.
756                          */
757                         unsigned long j;
758                         for (j = lno; j < hunk_end; j++)
759                                 if (!(sline[j].flag & (mark-1)))
760                                         null_context++;
761                         rlines -= null_context;
762                 }
763
764                 printf("%s%s", line_prefix, c_frag);
765                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
766                 for (i = 0; i < num_parent; i++)
767                         show_parent_lno(sline, lno, hunk_end, i, null_context);
768                 printf(" +%lu,%lu ", lno+1, rlines);
769                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
770
771                 if (hunk_comment) {
772                         int comment_end = 0;
773                         for (i = 0; i < 40; i++) {
774                                 int ch = hunk_comment[i] & 0xff;
775                                 if (!ch || ch == '\n')
776                                         break;
777                                 if (!isspace(ch))
778                                     comment_end = i;
779                         }
780                         if (comment_end)
781                                 printf("%s%s %s%s", c_reset,
782                                                     c_plain, c_reset,
783                                                     c_func);
784                         for (i = 0; i < comment_end; i++)
785                                 putchar(hunk_comment[i]);
786                 }
787
788                 printf("%s\n", c_reset);
789                 while (lno < hunk_end) {
790                         struct lline *ll;
791                         int j;
792                         unsigned long p_mask;
793                         struct sline *sl = &sline[lno++];
794                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
795                         while (ll) {
796                                 printf("%s%s", line_prefix, c_old);
797                                 for (j = 0; j < num_parent; j++) {
798                                         if (ll->parent_map & (1UL<<j))
799                                                 putchar('-');
800                                         else
801                                                 putchar(' ');
802                                 }
803                                 show_line_to_eol(ll->line, -1, c_reset);
804                                 ll = ll->next;
805                         }
806                         if (cnt < lno)
807                                 break;
808                         p_mask = 1;
809                         fputs(line_prefix, stdout);
810                         if (!(sl->flag & (mark-1))) {
811                                 /*
812                                  * This sline was here to hang the
813                                  * lost lines in front of it.
814                                  */
815                                 if (!context)
816                                         continue;
817                                 fputs(c_plain, stdout);
818                         }
819                         else
820                                 fputs(c_new, stdout);
821                         for (j = 0; j < num_parent; j++) {
822                                 if (p_mask & sl->flag)
823                                         putchar('+');
824                                 else
825                                         putchar(' ');
826                                 p_mask <<= 1;
827                         }
828                         show_line_to_eol(sl->bol, sl->len, c_reset);
829                 }
830         }
831 }
832
833 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
834                                int i, int j)
835 {
836         /* We have already examined parent j and we know parent i
837          * and parent j are the same, so reuse the combined result
838          * of parent j for parent i.
839          */
840         unsigned long lno, imask, jmask;
841         imask = (1UL<<i);
842         jmask = (1UL<<j);
843
844         for (lno = 0; lno <= cnt; lno++) {
845                 struct lline *ll = sline->lost;
846                 sline->p_lno[i] = sline->p_lno[j];
847                 while (ll) {
848                         if (ll->parent_map & jmask)
849                                 ll->parent_map |= imask;
850                         ll = ll->next;
851                 }
852                 if (sline->flag & jmask)
853                         sline->flag |= imask;
854                 sline++;
855         }
856         /* the overall size of the file (sline[cnt]) */
857         sline->p_lno[i] = sline->p_lno[j];
858 }
859
860 static void dump_quoted_path(const char *head,
861                              const char *prefix,
862                              const char *path,
863                              const char *line_prefix,
864                              const char *c_meta, const char *c_reset)
865 {
866         static struct strbuf buf = STRBUF_INIT;
867
868         strbuf_reset(&buf);
869         strbuf_addstr(&buf, line_prefix);
870         strbuf_addstr(&buf, c_meta);
871         strbuf_addstr(&buf, head);
872         quote_two_c_style(&buf, prefix, path, 0);
873         strbuf_addstr(&buf, c_reset);
874         puts(buf.buf);
875 }
876
877 static void show_combined_header(struct combine_diff_path *elem,
878                                  int num_parent,
879                                  int dense,
880                                  struct rev_info *rev,
881                                  const char *line_prefix,
882                                  int mode_differs,
883                                  int show_file_header)
884 {
885         struct diff_options *opt = &rev->diffopt;
886         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
887         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
888         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
889         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
890         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
891         const char *abb;
892         int added = 0;
893         int deleted = 0;
894         int i;
895
896         if (rev->loginfo && !rev->no_commit_id)
897                 show_log(rev);
898
899         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
900                          "", elem->path, line_prefix, c_meta, c_reset);
901         printf("%s%sindex ", line_prefix, c_meta);
902         for (i = 0; i < num_parent; i++) {
903                 abb = find_unique_abbrev(elem->parent[i].sha1,
904                                          abbrev);
905                 printf("%s%s", i ? "," : "", abb);
906         }
907         abb = find_unique_abbrev(elem->sha1, abbrev);
908         printf("..%s%s\n", abb, c_reset);
909
910         if (mode_differs) {
911                 deleted = !elem->mode;
912
913                 /* We say it was added if nobody had it */
914                 added = !deleted;
915                 for (i = 0; added && i < num_parent; i++)
916                         if (elem->parent[i].status !=
917                             DIFF_STATUS_ADDED)
918                                 added = 0;
919                 if (added)
920                         printf("%s%snew file mode %06o",
921                                line_prefix, c_meta, elem->mode);
922                 else {
923                         if (deleted)
924                                 printf("%s%sdeleted file ",
925                                        line_prefix, c_meta);
926                         printf("mode ");
927                         for (i = 0; i < num_parent; i++) {
928                                 printf("%s%06o", i ? "," : "",
929                                        elem->parent[i].mode);
930                         }
931                         if (elem->mode)
932                                 printf("..%06o", elem->mode);
933                 }
934                 printf("%s\n", c_reset);
935         }
936
937         if (!show_file_header)
938                 return;
939
940         if (added)
941                 dump_quoted_path("--- ", "", "/dev/null",
942                                  line_prefix, c_meta, c_reset);
943         else
944                 dump_quoted_path("--- ", a_prefix, elem->path,
945                                  line_prefix, c_meta, c_reset);
946         if (deleted)
947                 dump_quoted_path("+++ ", "", "/dev/null",
948                                  line_prefix, c_meta, c_reset);
949         else
950                 dump_quoted_path("+++ ", b_prefix, elem->path,
951                                  line_prefix, c_meta, c_reset);
952 }
953
954 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
955                             int dense, int working_tree_file,
956                             struct rev_info *rev)
957 {
958         struct diff_options *opt = &rev->diffopt;
959         unsigned long result_size, cnt, lno;
960         int result_deleted = 0;
961         char *result, *cp;
962         struct sline *sline; /* survived lines */
963         int mode_differs = 0;
964         int i, show_hunks;
965         mmfile_t result_file;
966         struct userdiff_driver *userdiff;
967         struct userdiff_driver *textconv = NULL;
968         int is_binary;
969         const char *line_prefix = diff_line_prefix(opt);
970
971         context = opt->context;
972         userdiff = userdiff_find_by_path(elem->path);
973         if (!userdiff)
974                 userdiff = userdiff_find_by_name("default");
975         if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV))
976                 textconv = userdiff_get_textconv(userdiff);
977
978         /* Read the result of merge first */
979         if (!working_tree_file)
980                 result = grab_blob(elem->sha1, elem->mode, &result_size,
981                                    textconv, elem->path);
982         else {
983                 /* Used by diff-tree to read from the working tree */
984                 struct stat st;
985                 int fd = -1;
986
987                 if (lstat(elem->path, &st) < 0)
988                         goto deleted_file;
989
990                 if (S_ISLNK(st.st_mode)) {
991                         struct strbuf buf = STRBUF_INIT;
992
993                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
994                                 error("readlink(%s): %s", elem->path,
995                                       strerror(errno));
996                                 return;
997                         }
998                         result_size = buf.len;
999                         result = strbuf_detach(&buf, NULL);
1000                         elem->mode = canon_mode(st.st_mode);
1001                 } else if (S_ISDIR(st.st_mode)) {
1002                         unsigned char sha1[20];
1003                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
1004                                 result = grab_blob(elem->sha1, elem->mode,
1005                                                    &result_size, NULL, NULL);
1006                         else
1007                                 result = grab_blob(sha1, elem->mode,
1008                                                    &result_size, NULL, NULL);
1009                 } else if (textconv) {
1010                         struct diff_filespec *df = alloc_filespec(elem->path);
1011                         fill_filespec(df, null_sha1, 0, st.st_mode);
1012                         result_size = fill_textconv(textconv, df, &result);
1013                         free_filespec(df);
1014                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1015                         size_t len = xsize_t(st.st_size);
1016                         ssize_t done;
1017                         int is_file, i;
1018
1019                         elem->mode = canon_mode(st.st_mode);
1020                         /* if symlinks don't work, assume symlink if all parents
1021                          * are symlinks
1022                          */
1023                         is_file = has_symlinks;
1024                         for (i = 0; !is_file && i < num_parent; i++)
1025                                 is_file = !S_ISLNK(elem->parent[i].mode);
1026                         if (!is_file)
1027                                 elem->mode = canon_mode(S_IFLNK);
1028
1029                         result_size = len;
1030                         result = xmalloc(len + 1);
1031
1032                         done = read_in_full(fd, result, len);
1033                         if (done < 0)
1034                                 die_errno("read error '%s'", elem->path);
1035                         else if (done < len)
1036                                 die("early EOF '%s'", elem->path);
1037
1038                         result[len] = 0;
1039
1040                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1041                         if (is_file) {
1042                                 struct strbuf buf = STRBUF_INIT;
1043
1044                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
1045                                         free(result);
1046                                         result = strbuf_detach(&buf, &len);
1047                                         result_size = len;
1048                                 }
1049                         }
1050                 }
1051                 else {
1052                 deleted_file:
1053                         result_deleted = 1;
1054                         result_size = 0;
1055                         elem->mode = 0;
1056                         result = xcalloc(1, 1);
1057                 }
1058
1059                 if (0 <= fd)
1060                         close(fd);
1061         }
1062
1063         for (i = 0; i < num_parent; i++) {
1064                 if (elem->parent[i].mode != elem->mode) {
1065                         mode_differs = 1;
1066                         break;
1067                 }
1068         }
1069
1070         if (textconv)
1071                 is_binary = 0;
1072         else if (userdiff->binary != -1)
1073                 is_binary = userdiff->binary;
1074         else {
1075                 is_binary = buffer_is_binary(result, result_size);
1076                 for (i = 0; !is_binary && i < num_parent; i++) {
1077                         char *buf;
1078                         unsigned long size;
1079                         buf = grab_blob(elem->parent[i].sha1,
1080                                         elem->parent[i].mode,
1081                                         &size, NULL, NULL);
1082                         if (buffer_is_binary(buf, size))
1083                                 is_binary = 1;
1084                         free(buf);
1085                 }
1086         }
1087         if (is_binary) {
1088                 show_combined_header(elem, num_parent, dense, rev,
1089                                      line_prefix, mode_differs, 0);
1090                 printf("Binary files differ\n");
1091                 free(result);
1092                 return;
1093         }
1094
1095         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1096                 if (*cp == '\n')
1097                         cnt++;
1098         }
1099         if (result_size && result[result_size-1] != '\n')
1100                 cnt++; /* incomplete line */
1101
1102         sline = xcalloc(cnt+2, sizeof(*sline));
1103         sline[0].bol = result;
1104         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1105                 if (*cp == '\n') {
1106                         sline[lno].len = cp - sline[lno].bol;
1107                         lno++;
1108                         if (lno < cnt)
1109                                 sline[lno].bol = cp + 1;
1110                 }
1111         }
1112         if (result_size && result[result_size-1] != '\n')
1113                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1114
1115         result_file.ptr = result;
1116         result_file.size = result_size;
1117
1118         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1119          * for deletion hunk at the end.
1120          */
1121         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
1122         for (lno = 0; lno <= cnt; lno++)
1123                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1124
1125         for (i = 0; i < num_parent; i++) {
1126                 int j;
1127                 for (j = 0; j < i; j++) {
1128                         if (!hashcmp(elem->parent[i].sha1,
1129                                      elem->parent[j].sha1)) {
1130                                 reuse_combine_diff(sline, cnt, i, j);
1131                                 break;
1132                         }
1133                 }
1134                 if (i <= j)
1135                         combine_diff(elem->parent[i].sha1,
1136                                      elem->parent[i].mode,
1137                                      &result_file, sline,
1138                                      cnt, i, num_parent, result_deleted,
1139                                      textconv, elem->path, opt->xdl_opts);
1140         }
1141
1142         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1143
1144         if (show_hunks || mode_differs || working_tree_file) {
1145                 show_combined_header(elem, num_parent, dense, rev,
1146                                      line_prefix, mode_differs, 1);
1147                 dump_sline(sline, line_prefix, cnt, num_parent,
1148                            opt->use_color, result_deleted);
1149         }
1150         free(result);
1151
1152         for (lno = 0; lno < cnt; lno++) {
1153                 if (sline[lno].lost) {
1154                         struct lline *ll = sline[lno].lost;
1155                         while (ll) {
1156                                 struct lline *tmp = ll;
1157                                 ll = ll->next;
1158                                 free(tmp);
1159                         }
1160                 }
1161         }
1162         free(sline[0].p_lno);
1163         free(sline);
1164 }
1165
1166 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1167 {
1168         struct diff_options *opt = &rev->diffopt;
1169         int line_termination, inter_name_termination, i;
1170         const char *line_prefix = diff_line_prefix(opt);
1171
1172         line_termination = opt->line_termination;
1173         inter_name_termination = '\t';
1174         if (!line_termination)
1175                 inter_name_termination = 0;
1176
1177         if (rev->loginfo && !rev->no_commit_id)
1178                 show_log(rev);
1179
1180
1181         if (opt->output_format & DIFF_FORMAT_RAW) {
1182                 printf("%s", line_prefix);
1183
1184                 /* As many colons as there are parents */
1185                 for (i = 0; i < num_parent; i++)
1186                         putchar(':');
1187
1188                 /* Show the modes */
1189                 for (i = 0; i < num_parent; i++)
1190                         printf("%06o ", p->parent[i].mode);
1191                 printf("%06o", p->mode);
1192
1193                 /* Show sha1's */
1194                 for (i = 0; i < num_parent; i++)
1195                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
1196                                                          opt->abbrev));
1197                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
1198         }
1199
1200         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1201                 for (i = 0; i < num_parent; i++)
1202                         putchar(p->parent[i].status);
1203                 putchar(inter_name_termination);
1204         }
1205
1206         write_name_quoted(p->path, stdout, line_termination);
1207 }
1208
1209 /*
1210  * The result (p->elem) is from the working tree and their
1211  * parents are typically from multiple stages during a merge
1212  * (i.e. diff-files) or the state in HEAD and in the index
1213  * (i.e. diff-index).
1214  */
1215 void show_combined_diff(struct combine_diff_path *p,
1216                        int num_parent,
1217                        int dense,
1218                        struct rev_info *rev)
1219 {
1220         struct diff_options *opt = &rev->diffopt;
1221
1222         if (!p->len)
1223                 return;
1224         if (opt->output_format & (DIFF_FORMAT_RAW |
1225                                   DIFF_FORMAT_NAME |
1226                                   DIFF_FORMAT_NAME_STATUS))
1227                 show_raw_diff(p, num_parent, rev);
1228         else if (opt->output_format & DIFF_FORMAT_PATCH)
1229                 show_patch_diff(p, num_parent, dense, 1, rev);
1230 }
1231
1232 static void free_combined_pair(struct diff_filepair *pair)
1233 {
1234         free(pair->two);
1235         free(pair);
1236 }
1237
1238 /*
1239  * A combine_diff_path expresses N parents on the LHS against 1 merge
1240  * result. Synthesize a diff_filepair that has N entries on the "one"
1241  * side and 1 entry on the "two" side.
1242  *
1243  * In the future, we might want to add more data to combine_diff_path
1244  * so that we can fill fields we are ignoring (most notably, size) here,
1245  * but currently nobody uses it, so this should suffice for now.
1246  */
1247 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1248                                            int num_parent)
1249 {
1250         int i;
1251         struct diff_filepair *pair;
1252         struct diff_filespec *pool;
1253
1254         pair = xmalloc(sizeof(*pair));
1255         pool = xcalloc(num_parent + 1, sizeof(struct diff_filespec));
1256         pair->one = pool + 1;
1257         pair->two = pool;
1258
1259         for (i = 0; i < num_parent; i++) {
1260                 pair->one[i].path = p->path;
1261                 pair->one[i].mode = p->parent[i].mode;
1262                 hashcpy(pair->one[i].sha1, p->parent[i].sha1);
1263                 pair->one[i].sha1_valid = !is_null_sha1(p->parent[i].sha1);
1264                 pair->one[i].has_more_entries = 1;
1265         }
1266         pair->one[num_parent - 1].has_more_entries = 0;
1267
1268         pair->two->path = p->path;
1269         pair->two->mode = p->mode;
1270         hashcpy(pair->two->sha1, p->sha1);
1271         pair->two->sha1_valid = !is_null_sha1(p->sha1);
1272         return pair;
1273 }
1274
1275 static void handle_combined_callback(struct diff_options *opt,
1276                                      struct combine_diff_path *paths,
1277                                      int num_parent,
1278                                      int num_paths)
1279 {
1280         struct combine_diff_path *p;
1281         struct diff_queue_struct q;
1282         int i;
1283
1284         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1285         q.alloc = num_paths;
1286         q.nr = num_paths;
1287         for (i = 0, p = paths; p; p = p->next) {
1288                 if (!p->len)
1289                         continue;
1290                 q.queue[i++] = combined_pair(p, num_parent);
1291         }
1292         opt->format_callback(&q, opt, opt->format_callback_data);
1293         for (i = 0; i < num_paths; i++)
1294                 free_combined_pair(q.queue[i]);
1295         free(q.queue);
1296 }
1297
1298 void diff_tree_combined(const unsigned char *sha1,
1299                         const struct sha1_array *parents,
1300                         int dense,
1301                         struct rev_info *rev)
1302 {
1303         struct diff_options *opt = &rev->diffopt;
1304         struct diff_options diffopts;
1305         struct combine_diff_path *p, *paths = NULL;
1306         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1307
1308         diffopts = *opt;
1309         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1310         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1311         DIFF_OPT_SET(&diffopts, RECURSIVE);
1312         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
1313
1314         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1315         needsep = 0;
1316         /* find set of paths that everybody touches */
1317         for (i = 0; i < num_parent; i++) {
1318                 /* show stat against the first parent even
1319                  * when doing combined diff.
1320                  */
1321                 int stat_opt = (opt->output_format &
1322                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1323                 if (i == 0 && stat_opt)
1324                         diffopts.output_format = stat_opt;
1325                 else
1326                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1327                 diff_tree_sha1(parents->sha1[i], sha1, "", &diffopts);
1328                 diffcore_std(&diffopts);
1329                 paths = intersect_paths(paths, i, num_parent);
1330
1331                 if (show_log_first && i == 0) {
1332                         show_log(rev);
1333
1334                         if (rev->verbose_header && opt->output_format)
1335                                 printf("%s%c", diff_line_prefix(opt),
1336                                        opt->line_termination);
1337                 }
1338                 diff_flush(&diffopts);
1339         }
1340
1341         /* find out surviving paths */
1342         for (num_paths = 0, p = paths; p; p = p->next) {
1343                 if (p->len)
1344                         num_paths++;
1345         }
1346         if (num_paths) {
1347                 if (opt->output_format & (DIFF_FORMAT_RAW |
1348                                           DIFF_FORMAT_NAME |
1349                                           DIFF_FORMAT_NAME_STATUS)) {
1350                         for (p = paths; p; p = p->next) {
1351                                 if (p->len)
1352                                         show_raw_diff(p, num_parent, rev);
1353                         }
1354                         needsep = 1;
1355                 }
1356                 else if (opt->output_format &
1357                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1358                         needsep = 1;
1359                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1360                         handle_combined_callback(opt, paths, num_parent, num_paths);
1361
1362                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1363                         if (needsep)
1364                                 printf("%s%c", diff_line_prefix(opt),
1365                                        opt->line_termination);
1366                         for (p = paths; p; p = p->next) {
1367                                 if (p->len)
1368                                         show_patch_diff(p, num_parent, dense,
1369                                                         0, rev);
1370                         }
1371                 }
1372         }
1373
1374         /* Clean things up */
1375         while (paths) {
1376                 struct combine_diff_path *tmp = paths;
1377                 paths = paths->next;
1378                 free(tmp);
1379         }
1380
1381         free_pathspec(&diffopts.pathspec);
1382 }
1383
1384 void diff_tree_combined_merge(const struct commit *commit, int dense,
1385                               struct rev_info *rev)
1386 {
1387         struct commit_list *parent = get_saved_parents(rev, commit);
1388         struct sha1_array parents = SHA1_ARRAY_INIT;
1389
1390         while (parent) {
1391                 sha1_array_append(&parents, parent->item->object.sha1);
1392                 parent = parent->next;
1393         }
1394         diff_tree_combined(commit->object.sha1, &parents, dense, rev);
1395         sha1_array_clear(&parents);
1396 }