merge-recursive: copy $GITHEAD strings
[git] / combine-diff.c
1 #include "cache.h"
2 #include "object-store.h"
3 #include "commit.h"
4 #include "blob.h"
5 #include "diff.h"
6 #include "diffcore.h"
7 #include "quote.h"
8 #include "xdiff-interface.h"
9 #include "xdiff/xmacros.h"
10 #include "log-tree.h"
11 #include "refs.h"
12 #include "userdiff.h"
13 #include "sha1-array.h"
14 #include "revision.h"
15
16 static int compare_paths(const struct combine_diff_path *one,
17                           const struct diff_filespec *two)
18 {
19         if (!S_ISDIR(one->mode) && !S_ISDIR(two->mode))
20                 return strcmp(one->path, two->path);
21
22         return base_name_compare(one->path, strlen(one->path), one->mode,
23                                  two->path, strlen(two->path), two->mode);
24 }
25
26 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
27 {
28         struct diff_queue_struct *q = &diff_queued_diff;
29         struct combine_diff_path *p, **tail = &curr;
30         int i, cmp;
31
32         if (!n) {
33                 for (i = 0; i < q->nr; i++) {
34                         int len;
35                         const char *path;
36                         if (diff_unmodified_pair(q->queue[i]))
37                                 continue;
38                         path = q->queue[i]->two->path;
39                         len = strlen(path);
40                         p = xmalloc(combine_diff_path_size(num_parent, len));
41                         p->path = (char *) &(p->parent[num_parent]);
42                         memcpy(p->path, path, len);
43                         p->path[len] = 0;
44                         p->next = NULL;
45                         memset(p->parent, 0,
46                                sizeof(p->parent[0]) * num_parent);
47
48                         oidcpy(&p->oid, &q->queue[i]->two->oid);
49                         p->mode = q->queue[i]->two->mode;
50                         oidcpy(&p->parent[n].oid, &q->queue[i]->one->oid);
51                         p->parent[n].mode = q->queue[i]->one->mode;
52                         p->parent[n].status = q->queue[i]->status;
53                         *tail = p;
54                         tail = &p->next;
55                 }
56                 return curr;
57         }
58
59         /*
60          * paths in curr (linked list) and q->queue[] (array) are
61          * both sorted in the tree order.
62          */
63         i = 0;
64         while ((p = *tail) != NULL) {
65                 cmp = ((i >= q->nr)
66                        ? -1 : compare_paths(p, q->queue[i]->two));
67
68                 if (cmp < 0) {
69                         /* p->path not in q->queue[]; drop it */
70                         *tail = p->next;
71                         free(p);
72                         continue;
73                 }
74
75                 if (cmp > 0) {
76                         /* q->queue[i] not in p->path; skip it */
77                         i++;
78                         continue;
79                 }
80
81                 oidcpy(&p->parent[n].oid, &q->queue[i]->one->oid);
82                 p->parent[n].mode = q->queue[i]->one->mode;
83                 p->parent[n].status = q->queue[i]->status;
84
85                 tail = &p->next;
86                 i++;
87         }
88         return curr;
89 }
90
91 /* Lines lost from parent */
92 struct lline {
93         struct lline *next, *prev;
94         int len;
95         unsigned long parent_map;
96         char line[FLEX_ARRAY];
97 };
98
99 /* Lines lost from current parent (before coalescing) */
100 struct plost {
101         struct lline *lost_head, *lost_tail;
102         int len;
103 };
104
105 /* Lines surviving in the merge result */
106 struct sline {
107         /* Accumulated and coalesced lost lines */
108         struct lline *lost;
109         int lenlost;
110         struct plost plost;
111         char *bol;
112         int len;
113         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
114          * we did not change it).
115          * bit N is used for "interesting" lines, including context.
116          * bit (N+1) is used for "do not show deletion before this".
117          */
118         unsigned long flag;
119         unsigned long *p_lno;
120 };
121
122 static int match_string_spaces(const char *line1, int len1,
123                                const char *line2, int len2,
124                                long flags)
125 {
126         if (flags & XDF_WHITESPACE_FLAGS) {
127                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
128                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
129         }
130
131         if (!(flags & (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE)))
132                 return (len1 == len2 && !memcmp(line1, line2, len1));
133
134         while (len1 > 0 && len2 > 0) {
135                 len1--;
136                 len2--;
137                 if (XDL_ISSPACE(line1[len1]) || XDL_ISSPACE(line2[len2])) {
138                         if ((flags & XDF_IGNORE_WHITESPACE_CHANGE) &&
139                             (!XDL_ISSPACE(line1[len1]) || !XDL_ISSPACE(line2[len2])))
140                                 return 0;
141
142                         for (; len1 > 0 && XDL_ISSPACE(line1[len1]); len1--);
143                         for (; len2 > 0 && XDL_ISSPACE(line2[len2]); len2--);
144                 }
145                 if (line1[len1] != line2[len2])
146                         return 0;
147         }
148
149         if (flags & XDF_IGNORE_WHITESPACE) {
150                 /* Consume remaining spaces */
151                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
152                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
153         }
154
155         /* We matched full line1 and line2 */
156         if (!len1 && !len2)
157                 return 1;
158
159         return 0;
160 }
161
162 enum coalesce_direction { MATCH, BASE, NEW };
163
164 /* Coalesce new lines into base by finding LCS */
165 static struct lline *coalesce_lines(struct lline *base, int *lenbase,
166                                     struct lline *newline, int lennew,
167                                     unsigned long parent, long flags)
168 {
169         int **lcs;
170         enum coalesce_direction **directions;
171         struct lline *baseend, *newend = NULL;
172         int i, j, origbaselen = *lenbase;
173
174         if (newline == NULL)
175                 return base;
176
177         if (base == NULL) {
178                 *lenbase = lennew;
179                 return newline;
180         }
181
182         /*
183          * Coalesce new lines into base by finding the LCS
184          * - Create the table to run dynamic programming
185          * - Compute the LCS
186          * - Then reverse read the direction structure:
187          *   - If we have MATCH, assign parent to base flag, and consume
188          *   both baseend and newend
189          *   - Else if we have BASE, consume baseend
190          *   - Else if we have NEW, insert newend lline into base and
191          *   consume newend
192          */
193         lcs = xcalloc(st_add(origbaselen, 1), sizeof(int*));
194         directions = xcalloc(st_add(origbaselen, 1), sizeof(enum coalesce_direction*));
195         for (i = 0; i < origbaselen + 1; i++) {
196                 lcs[i] = xcalloc(st_add(lennew, 1), sizeof(int));
197                 directions[i] = xcalloc(st_add(lennew, 1), sizeof(enum coalesce_direction));
198                 directions[i][0] = BASE;
199         }
200         for (j = 1; j < lennew + 1; j++)
201                 directions[0][j] = NEW;
202
203         for (i = 1, baseend = base; i < origbaselen + 1; i++) {
204                 for (j = 1, newend = newline; j < lennew + 1; j++) {
205                         if (match_string_spaces(baseend->line, baseend->len,
206                                                 newend->line, newend->len, flags)) {
207                                 lcs[i][j] = lcs[i - 1][j - 1] + 1;
208                                 directions[i][j] = MATCH;
209                         } else if (lcs[i][j - 1] >= lcs[i - 1][j]) {
210                                 lcs[i][j] = lcs[i][j - 1];
211                                 directions[i][j] = NEW;
212                         } else {
213                                 lcs[i][j] = lcs[i - 1][j];
214                                 directions[i][j] = BASE;
215                         }
216                         if (newend->next)
217                                 newend = newend->next;
218                 }
219                 if (baseend->next)
220                         baseend = baseend->next;
221         }
222
223         for (i = 0; i < origbaselen + 1; i++)
224                 free(lcs[i]);
225         free(lcs);
226
227         /* At this point, baseend and newend point to the end of each lists */
228         i--;
229         j--;
230         while (i != 0 || j != 0) {
231                 if (directions[i][j] == MATCH) {
232                         baseend->parent_map |= 1<<parent;
233                         baseend = baseend->prev;
234                         newend = newend->prev;
235                         i--;
236                         j--;
237                 } else if (directions[i][j] == NEW) {
238                         struct lline *lline;
239
240                         lline = newend;
241                         /* Remove lline from new list and update newend */
242                         if (lline->prev)
243                                 lline->prev->next = lline->next;
244                         else
245                                 newline = lline->next;
246                         if (lline->next)
247                                 lline->next->prev = lline->prev;
248
249                         newend = lline->prev;
250                         j--;
251
252                         /* Add lline to base list */
253                         if (baseend) {
254                                 lline->next = baseend->next;
255                                 lline->prev = baseend;
256                                 if (lline->prev)
257                                         lline->prev->next = lline;
258                         }
259                         else {
260                                 lline->next = base;
261                                 base = lline;
262                         }
263                         (*lenbase)++;
264
265                         if (lline->next)
266                                 lline->next->prev = lline;
267
268                 } else {
269                         baseend = baseend->prev;
270                         i--;
271                 }
272         }
273
274         newend = newline;
275         while (newend) {
276                 struct lline *lline = newend;
277                 newend = newend->next;
278                 free(lline);
279         }
280
281         for (i = 0; i < origbaselen + 1; i++)
282                 free(directions[i]);
283         free(directions);
284
285         return base;
286 }
287
288 static char *grab_blob(const struct object_id *oid, unsigned int mode,
289                        unsigned long *size, struct userdiff_driver *textconv,
290                        const char *path)
291 {
292         char *blob;
293         enum object_type type;
294
295         if (S_ISGITLINK(mode)) {
296                 struct strbuf buf = STRBUF_INIT;
297                 strbuf_addf(&buf, "Subproject commit %s\n", oid_to_hex(oid));
298                 *size = buf.len;
299                 blob = strbuf_detach(&buf, NULL);
300         } else if (is_null_oid(oid)) {
301                 /* deleted blob */
302                 *size = 0;
303                 return xcalloc(1, 1);
304         } else if (textconv) {
305                 struct diff_filespec *df = alloc_filespec(path);
306                 fill_filespec(df, oid, 1, mode);
307                 *size = fill_textconv(textconv, df, &blob);
308                 free_filespec(df);
309         } else {
310                 blob = read_object_file(oid, &type, size);
311                 if (type != OBJ_BLOB)
312                         die("object '%s' is not a blob!", oid_to_hex(oid));
313         }
314         return blob;
315 }
316
317 static void append_lost(struct sline *sline, int n, const char *line, int len)
318 {
319         struct lline *lline;
320         unsigned long this_mask = (1UL<<n);
321         if (line[len-1] == '\n')
322                 len--;
323
324         FLEX_ALLOC_MEM(lline, line, line, len);
325         lline->len = len;
326         lline->next = NULL;
327         lline->prev = sline->plost.lost_tail;
328         if (lline->prev)
329                 lline->prev->next = lline;
330         else
331                 sline->plost.lost_head = lline;
332         sline->plost.lost_tail = lline;
333         sline->plost.len++;
334         lline->parent_map = this_mask;
335 }
336
337 struct combine_diff_state {
338         unsigned int lno;
339         int ob, on, nb, nn;
340         unsigned long nmask;
341         int num_parent;
342         int n;
343         struct sline *sline;
344         struct sline *lost_bucket;
345 };
346
347 static void consume_line(void *state_, char *line, unsigned long len)
348 {
349         struct combine_diff_state *state = state_;
350         if (5 < len && !memcmp("@@ -", line, 4)) {
351                 if (parse_hunk_header(line, len,
352                                       &state->ob, &state->on,
353                                       &state->nb, &state->nn))
354                         return;
355                 state->lno = state->nb;
356                 if (state->nn == 0) {
357                         /* @@ -X,Y +N,0 @@ removed Y lines
358                          * that would have come *after* line N
359                          * in the result.  Our lost buckets hang
360                          * to the line after the removed lines,
361                          *
362                          * Note that this is correct even when N == 0,
363                          * in which case the hunk removes the first
364                          * line in the file.
365                          */
366                         state->lost_bucket = &state->sline[state->nb];
367                         if (!state->nb)
368                                 state->nb = 1;
369                 } else {
370                         state->lost_bucket = &state->sline[state->nb-1];
371                 }
372                 if (!state->sline[state->nb-1].p_lno)
373                         state->sline[state->nb-1].p_lno =
374                                 xcalloc(state->num_parent,
375                                         sizeof(unsigned long));
376                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
377                 return;
378         }
379         if (!state->lost_bucket)
380                 return; /* not in any hunk yet */
381         switch (line[0]) {
382         case '-':
383                 append_lost(state->lost_bucket, state->n, line+1, len-1);
384                 break;
385         case '+':
386                 state->sline[state->lno-1].flag |= state->nmask;
387                 state->lno++;
388                 break;
389         }
390 }
391
392 static void combine_diff(const struct object_id *parent, unsigned int mode,
393                          mmfile_t *result_file,
394                          struct sline *sline, unsigned int cnt, int n,
395                          int num_parent, int result_deleted,
396                          struct userdiff_driver *textconv,
397                          const char *path, long flags)
398 {
399         unsigned int p_lno, lno;
400         unsigned long nmask = (1UL << n);
401         xpparam_t xpp;
402         xdemitconf_t xecfg;
403         mmfile_t parent_file;
404         struct combine_diff_state state;
405         unsigned long sz;
406
407         if (result_deleted)
408                 return; /* result deleted */
409
410         parent_file.ptr = grab_blob(parent, mode, &sz, textconv, path);
411         parent_file.size = sz;
412         memset(&xpp, 0, sizeof(xpp));
413         xpp.flags = flags;
414         memset(&xecfg, 0, sizeof(xecfg));
415         memset(&state, 0, sizeof(state));
416         state.nmask = nmask;
417         state.sline = sline;
418         state.lno = 1;
419         state.num_parent = num_parent;
420         state.n = n;
421
422         if (xdi_diff_outf(&parent_file, result_file, consume_line, &state,
423                           &xpp, &xecfg))
424                 die("unable to generate combined diff for %s",
425                     oid_to_hex(parent));
426         free(parent_file.ptr);
427
428         /* Assign line numbers for this parent.
429          *
430          * sline[lno].p_lno[n] records the first line number
431          * (counting from 1) for parent N if the final hunk display
432          * started by showing sline[lno] (possibly showing the lost
433          * lines attached to it first).
434          */
435         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
436                 struct lline *ll;
437                 sline[lno].p_lno[n] = p_lno;
438
439                 /* Coalesce new lines */
440                 if (sline[lno].plost.lost_head) {
441                         struct sline *sl = &sline[lno];
442                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
443                                                   sl->plost.lost_head,
444                                                   sl->plost.len, n, flags);
445                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
446                         sl->plost.len = 0;
447                 }
448
449                 /* How many lines would this sline advance the p_lno? */
450                 ll = sline[lno].lost;
451                 while (ll) {
452                         if (ll->parent_map & nmask)
453                                 p_lno++; /* '-' means parent had it */
454                         ll = ll->next;
455                 }
456                 if (lno < cnt && !(sline[lno].flag & nmask))
457                         p_lno++; /* no '+' means parent had it */
458         }
459         sline[lno].p_lno[n] = p_lno; /* trailer */
460 }
461
462 static unsigned long context = 3;
463 static char combine_marker = '@';
464
465 static int interesting(struct sline *sline, unsigned long all_mask)
466 {
467         /* If some parents lost lines here, or if we have added to
468          * some parent, it is interesting.
469          */
470         return ((sline->flag & all_mask) || sline->lost);
471 }
472
473 static unsigned long adjust_hunk_tail(struct sline *sline,
474                                       unsigned long all_mask,
475                                       unsigned long hunk_begin,
476                                       unsigned long i)
477 {
478         /* i points at the first uninteresting line.  If the last line
479          * of the hunk was interesting only because it has some
480          * deletion, then it is not all that interesting for the
481          * purpose of giving trailing context lines.  This is because
482          * we output '-' line and then unmodified sline[i-1] itself in
483          * that case which gives us one extra context line.
484          */
485         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
486                 i--;
487         return i;
488 }
489
490 static unsigned long find_next(struct sline *sline,
491                                unsigned long mark,
492                                unsigned long i,
493                                unsigned long cnt,
494                                int look_for_uninteresting)
495 {
496         /* We have examined up to i-1 and are about to look at i.
497          * Find next interesting or uninteresting line.  Here,
498          * "interesting" does not mean interesting(), but marked by
499          * the give_context() function below (i.e. it includes context
500          * lines that are not interesting to interesting() function
501          * that are surrounded by interesting() ones.
502          */
503         while (i <= cnt)
504                 if (look_for_uninteresting
505                     ? !(sline[i].flag & mark)
506                     : (sline[i].flag & mark))
507                         return i;
508                 else
509                         i++;
510         return i;
511 }
512
513 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
514 {
515         unsigned long all_mask = (1UL<<num_parent) - 1;
516         unsigned long mark = (1UL<<num_parent);
517         unsigned long no_pre_delete = (2UL<<num_parent);
518         unsigned long i;
519
520         /* Two groups of interesting lines may have a short gap of
521          * uninteresting lines.  Connect such groups to give them a
522          * bit of context.
523          *
524          * We first start from what the interesting() function says,
525          * and mark them with "mark", and paint context lines with the
526          * mark.  So interesting() would still say false for such context
527          * lines but they are treated as "interesting" in the end.
528          */
529         i = find_next(sline, mark, 0, cnt, 0);
530         if (cnt < i)
531                 return 0;
532
533         while (i <= cnt) {
534                 unsigned long j = (context < i) ? (i - context) : 0;
535                 unsigned long k;
536
537                 /* Paint a few lines before the first interesting line. */
538                 while (j < i) {
539                         if (!(sline[j].flag & mark))
540                                 sline[j].flag |= no_pre_delete;
541                         sline[j++].flag |= mark;
542                 }
543
544         again:
545                 /* we know up to i is to be included.  where does the
546                  * next uninteresting one start?
547                  */
548                 j = find_next(sline, mark, i, cnt, 1);
549                 if (cnt < j)
550                         break; /* the rest are all interesting */
551
552                 /* lookahead context lines */
553                 k = find_next(sline, mark, j, cnt, 0);
554                 j = adjust_hunk_tail(sline, all_mask, i, j);
555
556                 if (k < j + context) {
557                         /* k is interesting and [j,k) are not, but
558                          * paint them interesting because the gap is small.
559                          */
560                         while (j < k)
561                                 sline[j++].flag |= mark;
562                         i = k;
563                         goto again;
564                 }
565
566                 /* j is the first uninteresting line and there is
567                  * no overlap beyond it within context lines.  Paint
568                  * the trailing edge a bit.
569                  */
570                 i = k;
571                 k = (j + context < cnt+1) ? j + context : cnt+1;
572                 while (j < k)
573                         sline[j++].flag |= mark;
574         }
575         return 1;
576 }
577
578 static int make_hunks(struct sline *sline, unsigned long cnt,
579                        int num_parent, int dense)
580 {
581         unsigned long all_mask = (1UL<<num_parent) - 1;
582         unsigned long mark = (1UL<<num_parent);
583         unsigned long i;
584         int has_interesting = 0;
585
586         for (i = 0; i <= cnt; i++) {
587                 if (interesting(&sline[i], all_mask))
588                         sline[i].flag |= mark;
589                 else
590                         sline[i].flag &= ~mark;
591         }
592         if (!dense)
593                 return give_context(sline, cnt, num_parent);
594
595         /* Look at each hunk, and if we have changes from only one
596          * parent, or the changes are the same from all but one
597          * parent, mark that uninteresting.
598          */
599         i = 0;
600         while (i <= cnt) {
601                 unsigned long j, hunk_begin, hunk_end;
602                 unsigned long same_diff;
603                 while (i <= cnt && !(sline[i].flag & mark))
604                         i++;
605                 if (cnt < i)
606                         break; /* No more interesting hunks */
607                 hunk_begin = i;
608                 for (j = i + 1; j <= cnt; j++) {
609                         if (!(sline[j].flag & mark)) {
610                                 /* Look beyond the end to see if there
611                                  * is an interesting line after this
612                                  * hunk within context span.
613                                  */
614                                 unsigned long la; /* lookahead */
615                                 int contin = 0;
616                                 la = adjust_hunk_tail(sline, all_mask,
617                                                      hunk_begin, j);
618                                 la = (la + context < cnt + 1) ?
619                                         (la + context) : cnt + 1;
620                                 while (la && j <= --la) {
621                                         if (sline[la].flag & mark) {
622                                                 contin = 1;
623                                                 break;
624                                         }
625                                 }
626                                 if (!contin)
627                                         break;
628                                 j = la;
629                         }
630                 }
631                 hunk_end = j;
632
633                 /* [i..hunk_end) are interesting.  Now is it really
634                  * interesting?  We check if there are only two versions
635                  * and the result matches one of them.  That is, we look
636                  * at:
637                  *   (+) line, which records lines added to which parents;
638                  *       this line appears in the result.
639                  *   (-) line, which records from what parents the line
640                  *       was removed; this line does not appear in the result.
641                  * then check the set of parents the result has difference
642                  * from, from all lines.  If there are lines that has
643                  * different set of parents that the result has differences
644                  * from, that means we have more than two versions.
645                  *
646                  * Even when we have only two versions, if the result does
647                  * not match any of the parents, the it should be considered
648                  * interesting.  In such a case, we would have all '+' line.
649                  * After passing the above "two versions" test, that would
650                  * appear as "the same set of parents" to be "all parents".
651                  */
652                 same_diff = 0;
653                 has_interesting = 0;
654                 for (j = i; j < hunk_end && !has_interesting; j++) {
655                         unsigned long this_diff = sline[j].flag & all_mask;
656                         struct lline *ll = sline[j].lost;
657                         if (this_diff) {
658                                 /* This has some changes.  Is it the
659                                  * same as others?
660                                  */
661                                 if (!same_diff)
662                                         same_diff = this_diff;
663                                 else if (same_diff != this_diff) {
664                                         has_interesting = 1;
665                                         break;
666                                 }
667                         }
668                         while (ll && !has_interesting) {
669                                 /* Lost this line from these parents;
670                                  * who are they?  Are they the same?
671                                  */
672                                 this_diff = ll->parent_map;
673                                 if (!same_diff)
674                                         same_diff = this_diff;
675                                 else if (same_diff != this_diff) {
676                                         has_interesting = 1;
677                                 }
678                                 ll = ll->next;
679                         }
680                 }
681
682                 if (!has_interesting && same_diff != all_mask) {
683                         /* This hunk is not that interesting after all */
684                         for (j = hunk_begin; j < hunk_end; j++)
685                                 sline[j].flag &= ~mark;
686                 }
687                 i = hunk_end;
688         }
689
690         has_interesting = give_context(sline, cnt, num_parent);
691         return has_interesting;
692 }
693
694 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
695 {
696         l0 = sline[l0].p_lno[n];
697         l1 = sline[l1].p_lno[n];
698         printf(" -%lu,%lu", l0, l1-l0-null_context);
699 }
700
701 static int hunk_comment_line(const char *bol)
702 {
703         int ch;
704
705         if (!bol)
706                 return 0;
707         ch = *bol & 0xff;
708         return (isalpha(ch) || ch == '_' || ch == '$');
709 }
710
711 static void show_line_to_eol(const char *line, int len, const char *reset)
712 {
713         int saw_cr_at_eol = 0;
714         if (len < 0)
715                 len = strlen(line);
716         saw_cr_at_eol = (len && line[len-1] == '\r');
717
718         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
719                reset,
720                saw_cr_at_eol ? "\r" : "");
721 }
722
723 static void dump_sline(struct sline *sline, const char *line_prefix,
724                        unsigned long cnt, int num_parent,
725                        int use_color, int result_deleted)
726 {
727         unsigned long mark = (1UL<<num_parent);
728         unsigned long no_pre_delete = (2UL<<num_parent);
729         int i;
730         unsigned long lno = 0;
731         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
732         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
733         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
734         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
735         const char *c_context = diff_get_color(use_color, DIFF_CONTEXT);
736         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
737
738         if (result_deleted)
739                 return; /* result deleted */
740
741         while (1) {
742                 unsigned long hunk_end;
743                 unsigned long rlines;
744                 const char *hunk_comment = NULL;
745                 unsigned long null_context = 0;
746
747                 while (lno <= cnt && !(sline[lno].flag & mark)) {
748                         if (hunk_comment_line(sline[lno].bol))
749                                 hunk_comment = sline[lno].bol;
750                         lno++;
751                 }
752                 if (cnt < lno)
753                         break;
754                 else {
755                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
756                                 if (!(sline[hunk_end].flag & mark))
757                                         break;
758                 }
759                 rlines = hunk_end - lno;
760                 if (cnt < hunk_end)
761                         rlines--; /* pointing at the last delete hunk */
762
763                 if (!context) {
764                         /*
765                          * Even when running with --unified=0, all
766                          * lines in the hunk needs to be processed in
767                          * the loop below in order to show the
768                          * deletion recorded in lost_head.  However,
769                          * we do not want to show the resulting line
770                          * with all blank context markers in such a
771                          * case.  Compensate.
772                          */
773                         unsigned long j;
774                         for (j = lno; j < hunk_end; j++)
775                                 if (!(sline[j].flag & (mark-1)))
776                                         null_context++;
777                         rlines -= null_context;
778                 }
779
780                 printf("%s%s", line_prefix, c_frag);
781                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
782                 for (i = 0; i < num_parent; i++)
783                         show_parent_lno(sline, lno, hunk_end, i, null_context);
784                 printf(" +%lu,%lu ", lno+1, rlines);
785                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
786
787                 if (hunk_comment) {
788                         int comment_end = 0;
789                         for (i = 0; i < 40; i++) {
790                                 int ch = hunk_comment[i] & 0xff;
791                                 if (!ch || ch == '\n')
792                                         break;
793                                 if (!isspace(ch))
794                                     comment_end = i;
795                         }
796                         if (comment_end)
797                                 printf("%s%s %s%s", c_reset,
798                                                     c_context, c_reset,
799                                                     c_func);
800                         for (i = 0; i < comment_end; i++)
801                                 putchar(hunk_comment[i]);
802                 }
803
804                 printf("%s\n", c_reset);
805                 while (lno < hunk_end) {
806                         struct lline *ll;
807                         int j;
808                         unsigned long p_mask;
809                         struct sline *sl = &sline[lno++];
810                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
811                         while (ll) {
812                                 printf("%s%s", line_prefix, c_old);
813                                 for (j = 0; j < num_parent; j++) {
814                                         if (ll->parent_map & (1UL<<j))
815                                                 putchar('-');
816                                         else
817                                                 putchar(' ');
818                                 }
819                                 show_line_to_eol(ll->line, -1, c_reset);
820                                 ll = ll->next;
821                         }
822                         if (cnt < lno)
823                                 break;
824                         p_mask = 1;
825                         fputs(line_prefix, stdout);
826                         if (!(sl->flag & (mark-1))) {
827                                 /*
828                                  * This sline was here to hang the
829                                  * lost lines in front of it.
830                                  */
831                                 if (!context)
832                                         continue;
833                                 fputs(c_context, stdout);
834                         }
835                         else
836                                 fputs(c_new, stdout);
837                         for (j = 0; j < num_parent; j++) {
838                                 if (p_mask & sl->flag)
839                                         putchar('+');
840                                 else
841                                         putchar(' ');
842                                 p_mask <<= 1;
843                         }
844                         show_line_to_eol(sl->bol, sl->len, c_reset);
845                 }
846         }
847 }
848
849 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
850                                int i, int j)
851 {
852         /* We have already examined parent j and we know parent i
853          * and parent j are the same, so reuse the combined result
854          * of parent j for parent i.
855          */
856         unsigned long lno, imask, jmask;
857         imask = (1UL<<i);
858         jmask = (1UL<<j);
859
860         for (lno = 0; lno <= cnt; lno++) {
861                 struct lline *ll = sline->lost;
862                 sline->p_lno[i] = sline->p_lno[j];
863                 while (ll) {
864                         if (ll->parent_map & jmask)
865                                 ll->parent_map |= imask;
866                         ll = ll->next;
867                 }
868                 if (sline->flag & jmask)
869                         sline->flag |= imask;
870                 sline++;
871         }
872         /* the overall size of the file (sline[cnt]) */
873         sline->p_lno[i] = sline->p_lno[j];
874 }
875
876 static void dump_quoted_path(const char *head,
877                              const char *prefix,
878                              const char *path,
879                              const char *line_prefix,
880                              const char *c_meta, const char *c_reset)
881 {
882         static struct strbuf buf = STRBUF_INIT;
883
884         strbuf_reset(&buf);
885         strbuf_addstr(&buf, line_prefix);
886         strbuf_addstr(&buf, c_meta);
887         strbuf_addstr(&buf, head);
888         quote_two_c_style(&buf, prefix, path, 0);
889         strbuf_addstr(&buf, c_reset);
890         puts(buf.buf);
891 }
892
893 static void show_combined_header(struct combine_diff_path *elem,
894                                  int num_parent,
895                                  int dense,
896                                  struct rev_info *rev,
897                                  const char *line_prefix,
898                                  int mode_differs,
899                                  int show_file_header)
900 {
901         struct diff_options *opt = &rev->diffopt;
902         int abbrev = opt->flags.full_index ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
903         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
904         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
905         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
906         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
907         const char *abb;
908         int added = 0;
909         int deleted = 0;
910         int i;
911
912         if (rev->loginfo && !rev->no_commit_id)
913                 show_log(rev);
914
915         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
916                          "", elem->path, line_prefix, c_meta, c_reset);
917         printf("%s%sindex ", line_prefix, c_meta);
918         for (i = 0; i < num_parent; i++) {
919                 abb = find_unique_abbrev(&elem->parent[i].oid,
920                                          abbrev);
921                 printf("%s%s", i ? "," : "", abb);
922         }
923         abb = find_unique_abbrev(&elem->oid, abbrev);
924         printf("..%s%s\n", abb, c_reset);
925
926         if (mode_differs) {
927                 deleted = !elem->mode;
928
929                 /* We say it was added if nobody had it */
930                 added = !deleted;
931                 for (i = 0; added && i < num_parent; i++)
932                         if (elem->parent[i].status !=
933                             DIFF_STATUS_ADDED)
934                                 added = 0;
935                 if (added)
936                         printf("%s%snew file mode %06o",
937                                line_prefix, c_meta, elem->mode);
938                 else {
939                         if (deleted)
940                                 printf("%s%sdeleted file ",
941                                        line_prefix, c_meta);
942                         printf("mode ");
943                         for (i = 0; i < num_parent; i++) {
944                                 printf("%s%06o", i ? "," : "",
945                                        elem->parent[i].mode);
946                         }
947                         if (elem->mode)
948                                 printf("..%06o", elem->mode);
949                 }
950                 printf("%s\n", c_reset);
951         }
952
953         if (!show_file_header)
954                 return;
955
956         if (added)
957                 dump_quoted_path("--- ", "", "/dev/null",
958                                  line_prefix, c_meta, c_reset);
959         else
960                 dump_quoted_path("--- ", a_prefix, elem->path,
961                                  line_prefix, c_meta, c_reset);
962         if (deleted)
963                 dump_quoted_path("+++ ", "", "/dev/null",
964                                  line_prefix, c_meta, c_reset);
965         else
966                 dump_quoted_path("+++ ", b_prefix, elem->path,
967                                  line_prefix, c_meta, c_reset);
968 }
969
970 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
971                             int dense, int working_tree_file,
972                             struct rev_info *rev)
973 {
974         struct diff_options *opt = &rev->diffopt;
975         unsigned long result_size, cnt, lno;
976         int result_deleted = 0;
977         char *result, *cp;
978         struct sline *sline; /* survived lines */
979         int mode_differs = 0;
980         int i, show_hunks;
981         mmfile_t result_file;
982         struct userdiff_driver *userdiff;
983         struct userdiff_driver *textconv = NULL;
984         int is_binary;
985         const char *line_prefix = diff_line_prefix(opt);
986
987         context = opt->context;
988         userdiff = userdiff_find_by_path(elem->path);
989         if (!userdiff)
990                 userdiff = userdiff_find_by_name("default");
991         if (opt->flags.allow_textconv)
992                 textconv = userdiff_get_textconv(userdiff);
993
994         /* Read the result of merge first */
995         if (!working_tree_file)
996                 result = grab_blob(&elem->oid, elem->mode, &result_size,
997                                    textconv, elem->path);
998         else {
999                 /* Used by diff-tree to read from the working tree */
1000                 struct stat st;
1001                 int fd = -1;
1002
1003                 if (lstat(elem->path, &st) < 0)
1004                         goto deleted_file;
1005
1006                 if (S_ISLNK(st.st_mode)) {
1007                         struct strbuf buf = STRBUF_INIT;
1008
1009                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
1010                                 error_errno("readlink(%s)", elem->path);
1011                                 return;
1012                         }
1013                         result_size = buf.len;
1014                         result = strbuf_detach(&buf, NULL);
1015                         elem->mode = canon_mode(st.st_mode);
1016                 } else if (S_ISDIR(st.st_mode)) {
1017                         struct object_id oid;
1018                         if (resolve_gitlink_ref(elem->path, "HEAD", &oid) < 0)
1019                                 result = grab_blob(&elem->oid, elem->mode,
1020                                                    &result_size, NULL, NULL);
1021                         else
1022                                 result = grab_blob(&oid, elem->mode,
1023                                                    &result_size, NULL, NULL);
1024                 } else if (textconv) {
1025                         struct diff_filespec *df = alloc_filespec(elem->path);
1026                         fill_filespec(df, &null_oid, 0, st.st_mode);
1027                         result_size = fill_textconv(textconv, df, &result);
1028                         free_filespec(df);
1029                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1030                         size_t len = xsize_t(st.st_size);
1031                         ssize_t done;
1032                         int is_file, i;
1033
1034                         elem->mode = canon_mode(st.st_mode);
1035                         /* if symlinks don't work, assume symlink if all parents
1036                          * are symlinks
1037                          */
1038                         is_file = has_symlinks;
1039                         for (i = 0; !is_file && i < num_parent; i++)
1040                                 is_file = !S_ISLNK(elem->parent[i].mode);
1041                         if (!is_file)
1042                                 elem->mode = canon_mode(S_IFLNK);
1043
1044                         result_size = len;
1045                         result = xmallocz(len);
1046
1047                         done = read_in_full(fd, result, len);
1048                         if (done < 0)
1049                                 die_errno("read error '%s'", elem->path);
1050                         else if (done < len)
1051                                 die("early EOF '%s'", elem->path);
1052
1053                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1054                         if (is_file) {
1055                                 struct strbuf buf = STRBUF_INIT;
1056
1057                                 if (convert_to_git(&the_index, elem->path, result, len, &buf, global_conv_flags_eol)) {
1058                                         free(result);
1059                                         result = strbuf_detach(&buf, &len);
1060                                         result_size = len;
1061                                 }
1062                         }
1063                 }
1064                 else {
1065                 deleted_file:
1066                         result_deleted = 1;
1067                         result_size = 0;
1068                         elem->mode = 0;
1069                         result = xcalloc(1, 1);
1070                 }
1071
1072                 if (0 <= fd)
1073                         close(fd);
1074         }
1075
1076         for (i = 0; i < num_parent; i++) {
1077                 if (elem->parent[i].mode != elem->mode) {
1078                         mode_differs = 1;
1079                         break;
1080                 }
1081         }
1082
1083         if (textconv)
1084                 is_binary = 0;
1085         else if (userdiff->binary != -1)
1086                 is_binary = userdiff->binary;
1087         else {
1088                 is_binary = buffer_is_binary(result, result_size);
1089                 for (i = 0; !is_binary && i < num_parent; i++) {
1090                         char *buf;
1091                         unsigned long size;
1092                         buf = grab_blob(&elem->parent[i].oid,
1093                                         elem->parent[i].mode,
1094                                         &size, NULL, NULL);
1095                         if (buffer_is_binary(buf, size))
1096                                 is_binary = 1;
1097                         free(buf);
1098                 }
1099         }
1100         if (is_binary) {
1101                 show_combined_header(elem, num_parent, dense, rev,
1102                                      line_prefix, mode_differs, 0);
1103                 printf("Binary files differ\n");
1104                 free(result);
1105                 return;
1106         }
1107
1108         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1109                 if (*cp == '\n')
1110                         cnt++;
1111         }
1112         if (result_size && result[result_size-1] != '\n')
1113                 cnt++; /* incomplete line */
1114
1115         sline = xcalloc(st_add(cnt, 2), sizeof(*sline));
1116         sline[0].bol = result;
1117         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1118                 if (*cp == '\n') {
1119                         sline[lno].len = cp - sline[lno].bol;
1120                         lno++;
1121                         if (lno < cnt)
1122                                 sline[lno].bol = cp + 1;
1123                 }
1124         }
1125         if (result_size && result[result_size-1] != '\n')
1126                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1127
1128         result_file.ptr = result;
1129         result_file.size = result_size;
1130
1131         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1132          * for deletion hunk at the end.
1133          */
1134         sline[0].p_lno = xcalloc(st_mult(st_add(cnt, 2), num_parent), sizeof(unsigned long));
1135         for (lno = 0; lno <= cnt; lno++)
1136                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1137
1138         for (i = 0; i < num_parent; i++) {
1139                 int j;
1140                 for (j = 0; j < i; j++) {
1141                         if (!oidcmp(&elem->parent[i].oid,
1142                                      &elem->parent[j].oid)) {
1143                                 reuse_combine_diff(sline, cnt, i, j);
1144                                 break;
1145                         }
1146                 }
1147                 if (i <= j)
1148                         combine_diff(&elem->parent[i].oid,
1149                                      elem->parent[i].mode,
1150                                      &result_file, sline,
1151                                      cnt, i, num_parent, result_deleted,
1152                                      textconv, elem->path, opt->xdl_opts);
1153         }
1154
1155         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1156
1157         if (show_hunks || mode_differs || working_tree_file) {
1158                 show_combined_header(elem, num_parent, dense, rev,
1159                                      line_prefix, mode_differs, 1);
1160                 dump_sline(sline, line_prefix, cnt, num_parent,
1161                            opt->use_color, result_deleted);
1162         }
1163         free(result);
1164
1165         for (lno = 0; lno < cnt; lno++) {
1166                 if (sline[lno].lost) {
1167                         struct lline *ll = sline[lno].lost;
1168                         while (ll) {
1169                                 struct lline *tmp = ll;
1170                                 ll = ll->next;
1171                                 free(tmp);
1172                         }
1173                 }
1174         }
1175         free(sline[0].p_lno);
1176         free(sline);
1177 }
1178
1179 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1180 {
1181         struct diff_options *opt = &rev->diffopt;
1182         int line_termination, inter_name_termination, i;
1183         const char *line_prefix = diff_line_prefix(opt);
1184
1185         line_termination = opt->line_termination;
1186         inter_name_termination = '\t';
1187         if (!line_termination)
1188                 inter_name_termination = 0;
1189
1190         if (rev->loginfo && !rev->no_commit_id)
1191                 show_log(rev);
1192
1193
1194         if (opt->output_format & DIFF_FORMAT_RAW) {
1195                 printf("%s", line_prefix);
1196
1197                 /* As many colons as there are parents */
1198                 for (i = 0; i < num_parent; i++)
1199                         putchar(':');
1200
1201                 /* Show the modes */
1202                 for (i = 0; i < num_parent; i++)
1203                         printf("%06o ", p->parent[i].mode);
1204                 printf("%06o", p->mode);
1205
1206                 /* Show sha1's */
1207                 for (i = 0; i < num_parent; i++)
1208                         printf(" %s", diff_aligned_abbrev(&p->parent[i].oid,
1209                                                           opt->abbrev));
1210                 printf(" %s ", diff_aligned_abbrev(&p->oid, opt->abbrev));
1211         }
1212
1213         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1214                 for (i = 0; i < num_parent; i++)
1215                         putchar(p->parent[i].status);
1216                 putchar(inter_name_termination);
1217         }
1218
1219         write_name_quoted(p->path, stdout, line_termination);
1220 }
1221
1222 /*
1223  * The result (p->elem) is from the working tree and their
1224  * parents are typically from multiple stages during a merge
1225  * (i.e. diff-files) or the state in HEAD and in the index
1226  * (i.e. diff-index).
1227  */
1228 void show_combined_diff(struct combine_diff_path *p,
1229                        int num_parent,
1230                        int dense,
1231                        struct rev_info *rev)
1232 {
1233         struct diff_options *opt = &rev->diffopt;
1234
1235         if (opt->output_format & (DIFF_FORMAT_RAW |
1236                                   DIFF_FORMAT_NAME |
1237                                   DIFF_FORMAT_NAME_STATUS))
1238                 show_raw_diff(p, num_parent, rev);
1239         else if (opt->output_format & DIFF_FORMAT_PATCH)
1240                 show_patch_diff(p, num_parent, dense, 1, rev);
1241 }
1242
1243 static void free_combined_pair(struct diff_filepair *pair)
1244 {
1245         free(pair->two);
1246         free(pair);
1247 }
1248
1249 /*
1250  * A combine_diff_path expresses N parents on the LHS against 1 merge
1251  * result. Synthesize a diff_filepair that has N entries on the "one"
1252  * side and 1 entry on the "two" side.
1253  *
1254  * In the future, we might want to add more data to combine_diff_path
1255  * so that we can fill fields we are ignoring (most notably, size) here,
1256  * but currently nobody uses it, so this should suffice for now.
1257  */
1258 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1259                                            int num_parent)
1260 {
1261         int i;
1262         struct diff_filepair *pair;
1263         struct diff_filespec *pool;
1264
1265         pair = xmalloc(sizeof(*pair));
1266         pool = xcalloc(st_add(num_parent, 1), sizeof(struct diff_filespec));
1267         pair->one = pool + 1;
1268         pair->two = pool;
1269
1270         for (i = 0; i < num_parent; i++) {
1271                 pair->one[i].path = p->path;
1272                 pair->one[i].mode = p->parent[i].mode;
1273                 oidcpy(&pair->one[i].oid, &p->parent[i].oid);
1274                 pair->one[i].oid_valid = !is_null_oid(&p->parent[i].oid);
1275                 pair->one[i].has_more_entries = 1;
1276         }
1277         pair->one[num_parent - 1].has_more_entries = 0;
1278
1279         pair->two->path = p->path;
1280         pair->two->mode = p->mode;
1281         oidcpy(&pair->two->oid, &p->oid);
1282         pair->two->oid_valid = !is_null_oid(&p->oid);
1283         return pair;
1284 }
1285
1286 static void handle_combined_callback(struct diff_options *opt,
1287                                      struct combine_diff_path *paths,
1288                                      int num_parent,
1289                                      int num_paths)
1290 {
1291         struct combine_diff_path *p;
1292         struct diff_queue_struct q;
1293         int i;
1294
1295         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1296         q.alloc = num_paths;
1297         q.nr = num_paths;
1298         for (i = 0, p = paths; p; p = p->next)
1299                 q.queue[i++] = combined_pair(p, num_parent);
1300         opt->format_callback(&q, opt, opt->format_callback_data);
1301         for (i = 0; i < num_paths; i++)
1302                 free_combined_pair(q.queue[i]);
1303         free(q.queue);
1304 }
1305
1306 static const char *path_path(void *obj)
1307 {
1308         struct combine_diff_path *path = (struct combine_diff_path *)obj;
1309
1310         return path->path;
1311 }
1312
1313
1314 /* find set of paths that every parent touches */
1315 static struct combine_diff_path *find_paths_generic(const struct object_id *oid,
1316         const struct oid_array *parents, struct diff_options *opt)
1317 {
1318         struct combine_diff_path *paths = NULL;
1319         int i, num_parent = parents->nr;
1320
1321         int output_format = opt->output_format;
1322         const char *orderfile = opt->orderfile;
1323
1324         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1325         /* tell diff_tree to emit paths in sorted (=tree) order */
1326         opt->orderfile = NULL;
1327
1328         /* D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)  (wrt paths) */
1329         for (i = 0; i < num_parent; i++) {
1330                 /*
1331                  * show stat against the first parent even when doing
1332                  * combined diff.
1333                  */
1334                 int stat_opt = (output_format &
1335                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1336                 if (i == 0 && stat_opt)
1337                         opt->output_format = stat_opt;
1338                 else
1339                         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1340                 diff_tree_oid(&parents->oid[i], oid, "", opt);
1341                 diffcore_std(opt);
1342                 paths = intersect_paths(paths, i, num_parent);
1343
1344                 /* if showing diff, show it in requested order */
1345                 if (opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1346                     orderfile) {
1347                         diffcore_order(orderfile);
1348                 }
1349
1350                 diff_flush(opt);
1351         }
1352
1353         opt->output_format = output_format;
1354         opt->orderfile = orderfile;
1355         return paths;
1356 }
1357
1358
1359 /*
1360  * find set of paths that everybody touches, assuming diff is run without
1361  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
1362  */
1363 static struct combine_diff_path *find_paths_multitree(
1364         const struct object_id *oid, const struct oid_array *parents,
1365         struct diff_options *opt)
1366 {
1367         int i, nparent = parents->nr;
1368         const struct object_id **parents_oid;
1369         struct combine_diff_path paths_head;
1370         struct strbuf base;
1371
1372         ALLOC_ARRAY(parents_oid, nparent);
1373         for (i = 0; i < nparent; i++)
1374                 parents_oid[i] = &parents->oid[i];
1375
1376         /* fake list head, so worker can assume it is non-NULL */
1377         paths_head.next = NULL;
1378
1379         strbuf_init(&base, PATH_MAX);
1380         diff_tree_paths(&paths_head, oid, parents_oid, nparent, &base, opt);
1381
1382         strbuf_release(&base);
1383         free(parents_oid);
1384         return paths_head.next;
1385 }
1386
1387
1388 void diff_tree_combined(const struct object_id *oid,
1389                         const struct oid_array *parents,
1390                         int dense,
1391                         struct rev_info *rev)
1392 {
1393         struct diff_options *opt = &rev->diffopt;
1394         struct diff_options diffopts;
1395         struct combine_diff_path *p, *paths;
1396         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1397         int need_generic_pathscan;
1398
1399         /* nothing to do, if no parents */
1400         if (!num_parent)
1401                 return;
1402
1403         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1404         needsep = 0;
1405         if (show_log_first) {
1406                 show_log(rev);
1407
1408                 if (rev->verbose_header && opt->output_format &&
1409                     opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1410                     !commit_format_is_empty(rev->commit_format))
1411                         printf("%s%c", diff_line_prefix(opt),
1412                                opt->line_termination);
1413         }
1414
1415         diffopts = *opt;
1416         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1417         diffopts.flags.recursive = 1;
1418         diffopts.flags.allow_external = 0;
1419
1420         /* find set of paths that everybody touches
1421          *
1422          * NOTE
1423          *
1424          * Diffcore transformations are bound to diff_filespec and logic
1425          * comparing two entries - i.e. they do not apply directly to combine
1426          * diff.
1427          *
1428          * If some of such transformations is requested - we launch generic
1429          * path scanning, which works significantly slower compared to
1430          * simultaneous all-trees-in-one-go scan in find_paths_multitree().
1431          *
1432          * TODO some of the filters could be ported to work on
1433          * combine_diff_paths - i.e. all functionality that skips paths, so in
1434          * theory, we could end up having only multitree path scanning.
1435          *
1436          * NOTE please keep this semantically in sync with diffcore_std()
1437          */
1438         need_generic_pathscan = opt->skip_stat_unmatch  ||
1439                         opt->flags.follow_renames       ||
1440                         opt->break_opt != -1    ||
1441                         opt->detect_rename      ||
1442                         (opt->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)   ||
1443                         opt->filter;
1444
1445
1446         if (need_generic_pathscan) {
1447                 /*
1448                  * NOTE generic case also handles --stat, as it computes
1449                  * diff(sha1,parent_i) for all i to do the job, specifically
1450                  * for parent0.
1451                  */
1452                 paths = find_paths_generic(oid, parents, &diffopts);
1453         }
1454         else {
1455                 int stat_opt;
1456                 paths = find_paths_multitree(oid, parents, &diffopts);
1457
1458                 /*
1459                  * show stat against the first parent even
1460                  * when doing combined diff.
1461                  */
1462                 stat_opt = (opt->output_format &
1463                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1464                 if (stat_opt) {
1465                         diffopts.output_format = stat_opt;
1466
1467                         diff_tree_oid(&parents->oid[0], oid, "", &diffopts);
1468                         diffcore_std(&diffopts);
1469                         if (opt->orderfile)
1470                                 diffcore_order(opt->orderfile);
1471                         diff_flush(&diffopts);
1472                 }
1473         }
1474
1475         /* find out number of surviving paths */
1476         for (num_paths = 0, p = paths; p; p = p->next)
1477                 num_paths++;
1478
1479         /* order paths according to diffcore_order */
1480         if (opt->orderfile && num_paths) {
1481                 struct obj_order *o;
1482
1483                 ALLOC_ARRAY(o, num_paths);
1484                 for (i = 0, p = paths; p; p = p->next, i++)
1485                         o[i].obj = p;
1486                 order_objects(opt->orderfile, path_path, o, num_paths);
1487                 for (i = 0; i < num_paths - 1; i++) {
1488                         p = o[i].obj;
1489                         p->next = o[i+1].obj;
1490                 }
1491
1492                 p = o[num_paths-1].obj;
1493                 p->next = NULL;
1494                 paths = o[0].obj;
1495                 free(o);
1496         }
1497
1498
1499         if (num_paths) {
1500                 if (opt->output_format & (DIFF_FORMAT_RAW |
1501                                           DIFF_FORMAT_NAME |
1502                                           DIFF_FORMAT_NAME_STATUS)) {
1503                         for (p = paths; p; p = p->next)
1504                                 show_raw_diff(p, num_parent, rev);
1505                         needsep = 1;
1506                 }
1507                 else if (opt->output_format &
1508                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1509                         needsep = 1;
1510                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1511                         handle_combined_callback(opt, paths, num_parent, num_paths);
1512
1513                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1514                         if (needsep)
1515                                 printf("%s%c", diff_line_prefix(opt),
1516                                        opt->line_termination);
1517                         for (p = paths; p; p = p->next)
1518                                 show_patch_diff(p, num_parent, dense,
1519                                                 0, rev);
1520                 }
1521         }
1522
1523         /* Clean things up */
1524         while (paths) {
1525                 struct combine_diff_path *tmp = paths;
1526                 paths = paths->next;
1527                 free(tmp);
1528         }
1529
1530         clear_pathspec(&diffopts.pathspec);
1531 }
1532
1533 void diff_tree_combined_merge(const struct commit *commit, int dense,
1534                               struct rev_info *rev)
1535 {
1536         struct commit_list *parent = get_saved_parents(rev, commit);
1537         struct oid_array parents = OID_ARRAY_INIT;
1538
1539         while (parent) {
1540                 oid_array_append(&parents, &parent->item->object.oid);
1541                 parent = parent->next;
1542         }
1543         diff_tree_combined(&commit->object.oid, &parents, dense, rev);
1544         oid_array_clear(&parents);
1545 }