Merge branch 'kl/pretty-doc-markup-fix'
[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(struct repository *r,
289                        const struct object_id *oid, unsigned int mode,
290                        unsigned long *size, struct userdiff_driver *textconv,
291                        const char *path)
292 {
293         char *blob;
294         enum object_type type;
295
296         if (S_ISGITLINK(mode)) {
297                 struct strbuf buf = STRBUF_INIT;
298                 strbuf_addf(&buf, "Subproject commit %s\n", oid_to_hex(oid));
299                 *size = buf.len;
300                 blob = strbuf_detach(&buf, NULL);
301         } else if (is_null_oid(oid)) {
302                 /* deleted blob */
303                 *size = 0;
304                 return xcalloc(1, 1);
305         } else if (textconv) {
306                 struct diff_filespec *df = alloc_filespec(path);
307                 fill_filespec(df, oid, 1, mode);
308                 *size = fill_textconv(r, textconv, df, &blob);
309                 free_filespec(df);
310         } else {
311                 blob = read_object_file(oid, &type, size);
312                 if (type != OBJ_BLOB)
313                         die("object '%s' is not a blob!", oid_to_hex(oid));
314         }
315         return blob;
316 }
317
318 static void append_lost(struct sline *sline, int n, const char *line, int len)
319 {
320         struct lline *lline;
321         unsigned long this_mask = (1UL<<n);
322         if (line[len-1] == '\n')
323                 len--;
324
325         FLEX_ALLOC_MEM(lline, line, line, len);
326         lline->len = len;
327         lline->next = NULL;
328         lline->prev = sline->plost.lost_tail;
329         if (lline->prev)
330                 lline->prev->next = lline;
331         else
332                 sline->plost.lost_head = lline;
333         sline->plost.lost_tail = lline;
334         sline->plost.len++;
335         lline->parent_map = this_mask;
336 }
337
338 struct combine_diff_state {
339         unsigned int lno;
340         int ob, on, nb, nn;
341         unsigned long nmask;
342         int num_parent;
343         int n;
344         struct sline *sline;
345         struct sline *lost_bucket;
346 };
347
348 static void consume_hunk(void *state_,
349                          long ob, long on,
350                          long nb, long nn,
351                          const char *funcline, long funclen)
352 {
353         struct combine_diff_state *state = state_;
354
355         state->ob = ob;
356         state->on = on;
357         state->nb = nb;
358         state->nn = nn;
359         state->lno = state->nb;
360         if (state->nn == 0) {
361                 /* @@ -X,Y +N,0 @@ removed Y lines
362                  * that would have come *after* line N
363                  * in the result.  Our lost buckets hang
364                  * to the line after the removed lines,
365                  *
366                  * Note that this is correct even when N == 0,
367                  * in which case the hunk removes the first
368                  * line in the file.
369                  */
370                 state->lost_bucket = &state->sline[state->nb];
371                 if (!state->nb)
372                         state->nb = 1;
373         } else {
374                 state->lost_bucket = &state->sline[state->nb-1];
375         }
376         if (!state->sline[state->nb-1].p_lno)
377                 state->sline[state->nb-1].p_lno =
378                         xcalloc(state->num_parent, sizeof(unsigned long));
379         state->sline[state->nb-1].p_lno[state->n] = state->ob;
380 }
381
382 static void consume_line(void *state_, char *line, unsigned long len)
383 {
384         struct combine_diff_state *state = state_;
385         if (!state->lost_bucket)
386                 return; /* not in any hunk yet */
387         switch (line[0]) {
388         case '-':
389                 append_lost(state->lost_bucket, state->n, line+1, len-1);
390                 break;
391         case '+':
392                 state->sline[state->lno-1].flag |= state->nmask;
393                 state->lno++;
394                 break;
395         }
396 }
397
398 static void combine_diff(struct repository *r,
399                          const struct object_id *parent, unsigned int mode,
400                          mmfile_t *result_file,
401                          struct sline *sline, unsigned int cnt, int n,
402                          int num_parent, int result_deleted,
403                          struct userdiff_driver *textconv,
404                          const char *path, long flags)
405 {
406         unsigned int p_lno, lno;
407         unsigned long nmask = (1UL << n);
408         xpparam_t xpp;
409         xdemitconf_t xecfg;
410         mmfile_t parent_file;
411         struct combine_diff_state state;
412         unsigned long sz;
413
414         if (result_deleted)
415                 return; /* result deleted */
416
417         parent_file.ptr = grab_blob(r, parent, mode, &sz, textconv, path);
418         parent_file.size = sz;
419         memset(&xpp, 0, sizeof(xpp));
420         xpp.flags = flags;
421         memset(&xecfg, 0, sizeof(xecfg));
422         memset(&state, 0, sizeof(state));
423         state.nmask = nmask;
424         state.sline = sline;
425         state.lno = 1;
426         state.num_parent = num_parent;
427         state.n = n;
428
429         if (xdi_diff_outf(&parent_file, result_file, consume_hunk,
430                           consume_line, &state, &xpp, &xecfg))
431                 die("unable to generate combined diff for %s",
432                     oid_to_hex(parent));
433         free(parent_file.ptr);
434
435         /* Assign line numbers for this parent.
436          *
437          * sline[lno].p_lno[n] records the first line number
438          * (counting from 1) for parent N if the final hunk display
439          * started by showing sline[lno] (possibly showing the lost
440          * lines attached to it first).
441          */
442         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
443                 struct lline *ll;
444                 sline[lno].p_lno[n] = p_lno;
445
446                 /* Coalesce new lines */
447                 if (sline[lno].plost.lost_head) {
448                         struct sline *sl = &sline[lno];
449                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
450                                                   sl->plost.lost_head,
451                                                   sl->plost.len, n, flags);
452                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
453                         sl->plost.len = 0;
454                 }
455
456                 /* How many lines would this sline advance the p_lno? */
457                 ll = sline[lno].lost;
458                 while (ll) {
459                         if (ll->parent_map & nmask)
460                                 p_lno++; /* '-' means parent had it */
461                         ll = ll->next;
462                 }
463                 if (lno < cnt && !(sline[lno].flag & nmask))
464                         p_lno++; /* no '+' means parent had it */
465         }
466         sline[lno].p_lno[n] = p_lno; /* trailer */
467 }
468
469 static unsigned long context = 3;
470 static char combine_marker = '@';
471
472 static int interesting(struct sline *sline, unsigned long all_mask)
473 {
474         /* If some parents lost lines here, or if we have added to
475          * some parent, it is interesting.
476          */
477         return ((sline->flag & all_mask) || sline->lost);
478 }
479
480 static unsigned long adjust_hunk_tail(struct sline *sline,
481                                       unsigned long all_mask,
482                                       unsigned long hunk_begin,
483                                       unsigned long i)
484 {
485         /* i points at the first uninteresting line.  If the last line
486          * of the hunk was interesting only because it has some
487          * deletion, then it is not all that interesting for the
488          * purpose of giving trailing context lines.  This is because
489          * we output '-' line and then unmodified sline[i-1] itself in
490          * that case which gives us one extra context line.
491          */
492         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
493                 i--;
494         return i;
495 }
496
497 static unsigned long find_next(struct sline *sline,
498                                unsigned long mark,
499                                unsigned long i,
500                                unsigned long cnt,
501                                int look_for_uninteresting)
502 {
503         /* We have examined up to i-1 and are about to look at i.
504          * Find next interesting or uninteresting line.  Here,
505          * "interesting" does not mean interesting(), but marked by
506          * the give_context() function below (i.e. it includes context
507          * lines that are not interesting to interesting() function
508          * that are surrounded by interesting() ones.
509          */
510         while (i <= cnt)
511                 if (look_for_uninteresting
512                     ? !(sline[i].flag & mark)
513                     : (sline[i].flag & mark))
514                         return i;
515                 else
516                         i++;
517         return i;
518 }
519
520 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
521 {
522         unsigned long all_mask = (1UL<<num_parent) - 1;
523         unsigned long mark = (1UL<<num_parent);
524         unsigned long no_pre_delete = (2UL<<num_parent);
525         unsigned long i;
526
527         /* Two groups of interesting lines may have a short gap of
528          * uninteresting lines.  Connect such groups to give them a
529          * bit of context.
530          *
531          * We first start from what the interesting() function says,
532          * and mark them with "mark", and paint context lines with the
533          * mark.  So interesting() would still say false for such context
534          * lines but they are treated as "interesting" in the end.
535          */
536         i = find_next(sline, mark, 0, cnt, 0);
537         if (cnt < i)
538                 return 0;
539
540         while (i <= cnt) {
541                 unsigned long j = (context < i) ? (i - context) : 0;
542                 unsigned long k;
543
544                 /* Paint a few lines before the first interesting line. */
545                 while (j < i) {
546                         if (!(sline[j].flag & mark))
547                                 sline[j].flag |= no_pre_delete;
548                         sline[j++].flag |= mark;
549                 }
550
551         again:
552                 /* we know up to i is to be included.  where does the
553                  * next uninteresting one start?
554                  */
555                 j = find_next(sline, mark, i, cnt, 1);
556                 if (cnt < j)
557                         break; /* the rest are all interesting */
558
559                 /* lookahead context lines */
560                 k = find_next(sline, mark, j, cnt, 0);
561                 j = adjust_hunk_tail(sline, all_mask, i, j);
562
563                 if (k < j + context) {
564                         /* k is interesting and [j,k) are not, but
565                          * paint them interesting because the gap is small.
566                          */
567                         while (j < k)
568                                 sline[j++].flag |= mark;
569                         i = k;
570                         goto again;
571                 }
572
573                 /* j is the first uninteresting line and there is
574                  * no overlap beyond it within context lines.  Paint
575                  * the trailing edge a bit.
576                  */
577                 i = k;
578                 k = (j + context < cnt+1) ? j + context : cnt+1;
579                 while (j < k)
580                         sline[j++].flag |= mark;
581         }
582         return 1;
583 }
584
585 static int make_hunks(struct sline *sline, unsigned long cnt,
586                        int num_parent, int dense)
587 {
588         unsigned long all_mask = (1UL<<num_parent) - 1;
589         unsigned long mark = (1UL<<num_parent);
590         unsigned long i;
591         int has_interesting = 0;
592
593         for (i = 0; i <= cnt; i++) {
594                 if (interesting(&sline[i], all_mask))
595                         sline[i].flag |= mark;
596                 else
597                         sline[i].flag &= ~mark;
598         }
599         if (!dense)
600                 return give_context(sline, cnt, num_parent);
601
602         /* Look at each hunk, and if we have changes from only one
603          * parent, or the changes are the same from all but one
604          * parent, mark that uninteresting.
605          */
606         i = 0;
607         while (i <= cnt) {
608                 unsigned long j, hunk_begin, hunk_end;
609                 unsigned long same_diff;
610                 while (i <= cnt && !(sline[i].flag & mark))
611                         i++;
612                 if (cnt < i)
613                         break; /* No more interesting hunks */
614                 hunk_begin = i;
615                 for (j = i + 1; j <= cnt; j++) {
616                         if (!(sline[j].flag & mark)) {
617                                 /* Look beyond the end to see if there
618                                  * is an interesting line after this
619                                  * hunk within context span.
620                                  */
621                                 unsigned long la; /* lookahead */
622                                 int contin = 0;
623                                 la = adjust_hunk_tail(sline, all_mask,
624                                                      hunk_begin, j);
625                                 la = (la + context < cnt + 1) ?
626                                         (la + context) : cnt + 1;
627                                 while (la && j <= --la) {
628                                         if (sline[la].flag & mark) {
629                                                 contin = 1;
630                                                 break;
631                                         }
632                                 }
633                                 if (!contin)
634                                         break;
635                                 j = la;
636                         }
637                 }
638                 hunk_end = j;
639
640                 /* [i..hunk_end) are interesting.  Now is it really
641                  * interesting?  We check if there are only two versions
642                  * and the result matches one of them.  That is, we look
643                  * at:
644                  *   (+) line, which records lines added to which parents;
645                  *       this line appears in the result.
646                  *   (-) line, which records from what parents the line
647                  *       was removed; this line does not appear in the result.
648                  * then check the set of parents the result has difference
649                  * from, from all lines.  If there are lines that has
650                  * different set of parents that the result has differences
651                  * from, that means we have more than two versions.
652                  *
653                  * Even when we have only two versions, if the result does
654                  * not match any of the parents, the it should be considered
655                  * interesting.  In such a case, we would have all '+' line.
656                  * After passing the above "two versions" test, that would
657                  * appear as "the same set of parents" to be "all parents".
658                  */
659                 same_diff = 0;
660                 has_interesting = 0;
661                 for (j = i; j < hunk_end && !has_interesting; j++) {
662                         unsigned long this_diff = sline[j].flag & all_mask;
663                         struct lline *ll = sline[j].lost;
664                         if (this_diff) {
665                                 /* This has some changes.  Is it the
666                                  * same as others?
667                                  */
668                                 if (!same_diff)
669                                         same_diff = this_diff;
670                                 else if (same_diff != this_diff) {
671                                         has_interesting = 1;
672                                         break;
673                                 }
674                         }
675                         while (ll && !has_interesting) {
676                                 /* Lost this line from these parents;
677                                  * who are they?  Are they the same?
678                                  */
679                                 this_diff = ll->parent_map;
680                                 if (!same_diff)
681                                         same_diff = this_diff;
682                                 else if (same_diff != this_diff) {
683                                         has_interesting = 1;
684                                 }
685                                 ll = ll->next;
686                         }
687                 }
688
689                 if (!has_interesting && same_diff != all_mask) {
690                         /* This hunk is not that interesting after all */
691                         for (j = hunk_begin; j < hunk_end; j++)
692                                 sline[j].flag &= ~mark;
693                 }
694                 i = hunk_end;
695         }
696
697         has_interesting = give_context(sline, cnt, num_parent);
698         return has_interesting;
699 }
700
701 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
702 {
703         l0 = sline[l0].p_lno[n];
704         l1 = sline[l1].p_lno[n];
705         printf(" -%lu,%lu", l0, l1-l0-null_context);
706 }
707
708 static int hunk_comment_line(const char *bol)
709 {
710         int ch;
711
712         if (!bol)
713                 return 0;
714         ch = *bol & 0xff;
715         return (isalpha(ch) || ch == '_' || ch == '$');
716 }
717
718 static void show_line_to_eol(const char *line, int len, const char *reset)
719 {
720         int saw_cr_at_eol = 0;
721         if (len < 0)
722                 len = strlen(line);
723         saw_cr_at_eol = (len && line[len-1] == '\r');
724
725         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
726                reset,
727                saw_cr_at_eol ? "\r" : "");
728 }
729
730 static void dump_sline(struct sline *sline, const char *line_prefix,
731                        unsigned long cnt, int num_parent,
732                        int use_color, int result_deleted)
733 {
734         unsigned long mark = (1UL<<num_parent);
735         unsigned long no_pre_delete = (2UL<<num_parent);
736         int i;
737         unsigned long lno = 0;
738         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
739         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
740         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
741         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
742         const char *c_context = diff_get_color(use_color, DIFF_CONTEXT);
743         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
744
745         if (result_deleted)
746                 return; /* result deleted */
747
748         while (1) {
749                 unsigned long hunk_end;
750                 unsigned long rlines;
751                 const char *hunk_comment = NULL;
752                 unsigned long null_context = 0;
753
754                 while (lno <= cnt && !(sline[lno].flag & mark)) {
755                         if (hunk_comment_line(sline[lno].bol))
756                                 hunk_comment = sline[lno].bol;
757                         lno++;
758                 }
759                 if (cnt < lno)
760                         break;
761                 else {
762                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
763                                 if (!(sline[hunk_end].flag & mark))
764                                         break;
765                 }
766                 rlines = hunk_end - lno;
767                 if (cnt < hunk_end)
768                         rlines--; /* pointing at the last delete hunk */
769
770                 if (!context) {
771                         /*
772                          * Even when running with --unified=0, all
773                          * lines in the hunk needs to be processed in
774                          * the loop below in order to show the
775                          * deletion recorded in lost_head.  However,
776                          * we do not want to show the resulting line
777                          * with all blank context markers in such a
778                          * case.  Compensate.
779                          */
780                         unsigned long j;
781                         for (j = lno; j < hunk_end; j++)
782                                 if (!(sline[j].flag & (mark-1)))
783                                         null_context++;
784                         rlines -= null_context;
785                 }
786
787                 printf("%s%s", line_prefix, c_frag);
788                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
789                 for (i = 0; i < num_parent; i++)
790                         show_parent_lno(sline, lno, hunk_end, i, null_context);
791                 printf(" +%lu,%lu ", lno+1, rlines);
792                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
793
794                 if (hunk_comment) {
795                         int comment_end = 0;
796                         for (i = 0; i < 40; i++) {
797                                 int ch = hunk_comment[i] & 0xff;
798                                 if (!ch || ch == '\n')
799                                         break;
800                                 if (!isspace(ch))
801                                     comment_end = i;
802                         }
803                         if (comment_end)
804                                 printf("%s%s %s%s", c_reset,
805                                                     c_context, c_reset,
806                                                     c_func);
807                         for (i = 0; i < comment_end; i++)
808                                 putchar(hunk_comment[i]);
809                 }
810
811                 printf("%s\n", c_reset);
812                 while (lno < hunk_end) {
813                         struct lline *ll;
814                         int j;
815                         unsigned long p_mask;
816                         struct sline *sl = &sline[lno++];
817                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
818                         while (ll) {
819                                 printf("%s%s", line_prefix, c_old);
820                                 for (j = 0; j < num_parent; j++) {
821                                         if (ll->parent_map & (1UL<<j))
822                                                 putchar('-');
823                                         else
824                                                 putchar(' ');
825                                 }
826                                 show_line_to_eol(ll->line, -1, c_reset);
827                                 ll = ll->next;
828                         }
829                         if (cnt < lno)
830                                 break;
831                         p_mask = 1;
832                         fputs(line_prefix, stdout);
833                         if (!(sl->flag & (mark-1))) {
834                                 /*
835                                  * This sline was here to hang the
836                                  * lost lines in front of it.
837                                  */
838                                 if (!context)
839                                         continue;
840                                 fputs(c_context, stdout);
841                         }
842                         else
843                                 fputs(c_new, stdout);
844                         for (j = 0; j < num_parent; j++) {
845                                 if (p_mask & sl->flag)
846                                         putchar('+');
847                                 else
848                                         putchar(' ');
849                                 p_mask <<= 1;
850                         }
851                         show_line_to_eol(sl->bol, sl->len, c_reset);
852                 }
853         }
854 }
855
856 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
857                                int i, int j)
858 {
859         /* We have already examined parent j and we know parent i
860          * and parent j are the same, so reuse the combined result
861          * of parent j for parent i.
862          */
863         unsigned long lno, imask, jmask;
864         imask = (1UL<<i);
865         jmask = (1UL<<j);
866
867         for (lno = 0; lno <= cnt; lno++) {
868                 struct lline *ll = sline->lost;
869                 sline->p_lno[i] = sline->p_lno[j];
870                 while (ll) {
871                         if (ll->parent_map & jmask)
872                                 ll->parent_map |= imask;
873                         ll = ll->next;
874                 }
875                 if (sline->flag & jmask)
876                         sline->flag |= imask;
877                 sline++;
878         }
879         /* the overall size of the file (sline[cnt]) */
880         sline->p_lno[i] = sline->p_lno[j];
881 }
882
883 static void dump_quoted_path(const char *head,
884                              const char *prefix,
885                              const char *path,
886                              const char *line_prefix,
887                              const char *c_meta, const char *c_reset)
888 {
889         static struct strbuf buf = STRBUF_INIT;
890
891         strbuf_reset(&buf);
892         strbuf_addstr(&buf, line_prefix);
893         strbuf_addstr(&buf, c_meta);
894         strbuf_addstr(&buf, head);
895         quote_two_c_style(&buf, prefix, path, 0);
896         strbuf_addstr(&buf, c_reset);
897         puts(buf.buf);
898 }
899
900 static void show_combined_header(struct combine_diff_path *elem,
901                                  int num_parent,
902                                  int dense,
903                                  struct rev_info *rev,
904                                  const char *line_prefix,
905                                  int mode_differs,
906                                  int show_file_header)
907 {
908         struct diff_options *opt = &rev->diffopt;
909         int abbrev = opt->flags.full_index ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
910         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
911         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
912         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
913         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
914         const char *abb;
915         int added = 0;
916         int deleted = 0;
917         int i;
918
919         if (rev->loginfo && !rev->no_commit_id)
920                 show_log(rev);
921
922         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
923                          "", elem->path, line_prefix, c_meta, c_reset);
924         printf("%s%sindex ", line_prefix, c_meta);
925         for (i = 0; i < num_parent; i++) {
926                 abb = find_unique_abbrev(&elem->parent[i].oid,
927                                          abbrev);
928                 printf("%s%s", i ? "," : "", abb);
929         }
930         abb = find_unique_abbrev(&elem->oid, abbrev);
931         printf("..%s%s\n", abb, c_reset);
932
933         if (mode_differs) {
934                 deleted = !elem->mode;
935
936                 /* We say it was added if nobody had it */
937                 added = !deleted;
938                 for (i = 0; added && i < num_parent; i++)
939                         if (elem->parent[i].status !=
940                             DIFF_STATUS_ADDED)
941                                 added = 0;
942                 if (added)
943                         printf("%s%snew file mode %06o",
944                                line_prefix, c_meta, elem->mode);
945                 else {
946                         if (deleted)
947                                 printf("%s%sdeleted file ",
948                                        line_prefix, c_meta);
949                         printf("mode ");
950                         for (i = 0; i < num_parent; i++) {
951                                 printf("%s%06o", i ? "," : "",
952                                        elem->parent[i].mode);
953                         }
954                         if (elem->mode)
955                                 printf("..%06o", elem->mode);
956                 }
957                 printf("%s\n", c_reset);
958         }
959
960         if (!show_file_header)
961                 return;
962
963         if (added)
964                 dump_quoted_path("--- ", "", "/dev/null",
965                                  line_prefix, c_meta, c_reset);
966         else
967                 dump_quoted_path("--- ", a_prefix, elem->path,
968                                  line_prefix, c_meta, c_reset);
969         if (deleted)
970                 dump_quoted_path("+++ ", "", "/dev/null",
971                                  line_prefix, c_meta, c_reset);
972         else
973                 dump_quoted_path("+++ ", b_prefix, elem->path,
974                                  line_prefix, c_meta, c_reset);
975 }
976
977 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
978                             int dense, int working_tree_file,
979                             struct rev_info *rev)
980 {
981         struct diff_options *opt = &rev->diffopt;
982         unsigned long result_size, cnt, lno;
983         int result_deleted = 0;
984         char *result, *cp;
985         struct sline *sline; /* survived lines */
986         int mode_differs = 0;
987         int i, show_hunks;
988         mmfile_t result_file;
989         struct userdiff_driver *userdiff;
990         struct userdiff_driver *textconv = NULL;
991         int is_binary;
992         const char *line_prefix = diff_line_prefix(opt);
993
994         context = opt->context;
995         userdiff = userdiff_find_by_path(opt->repo->index, elem->path);
996         if (!userdiff)
997                 userdiff = userdiff_find_by_name("default");
998         if (opt->flags.allow_textconv)
999                 textconv = userdiff_get_textconv(opt->repo, userdiff);
1000
1001         /* Read the result of merge first */
1002         if (!working_tree_file)
1003                 result = grab_blob(opt->repo, &elem->oid, elem->mode, &result_size,
1004                                    textconv, elem->path);
1005         else {
1006                 /* Used by diff-tree to read from the working tree */
1007                 struct stat st;
1008                 int fd = -1;
1009
1010                 if (lstat(elem->path, &st) < 0)
1011                         goto deleted_file;
1012
1013                 if (S_ISLNK(st.st_mode)) {
1014                         struct strbuf buf = STRBUF_INIT;
1015
1016                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
1017                                 error_errno("readlink(%s)", elem->path);
1018                                 return;
1019                         }
1020                         result_size = buf.len;
1021                         result = strbuf_detach(&buf, NULL);
1022                         elem->mode = canon_mode(st.st_mode);
1023                 } else if (S_ISDIR(st.st_mode)) {
1024                         struct object_id oid;
1025                         if (resolve_gitlink_ref(elem->path, "HEAD", &oid) < 0)
1026                                 result = grab_blob(opt->repo, &elem->oid,
1027                                                    elem->mode, &result_size,
1028                                                    NULL, NULL);
1029                         else
1030                                 result = grab_blob(opt->repo, &oid, elem->mode,
1031                                                    &result_size, NULL, NULL);
1032                 } else if (textconv) {
1033                         struct diff_filespec *df = alloc_filespec(elem->path);
1034                         fill_filespec(df, &null_oid, 0, st.st_mode);
1035                         result_size = fill_textconv(opt->repo, textconv, df, &result);
1036                         free_filespec(df);
1037                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1038                         size_t len = xsize_t(st.st_size);
1039                         ssize_t done;
1040                         int is_file, i;
1041
1042                         elem->mode = canon_mode(st.st_mode);
1043                         /* if symlinks don't work, assume symlink if all parents
1044                          * are symlinks
1045                          */
1046                         is_file = has_symlinks;
1047                         for (i = 0; !is_file && i < num_parent; i++)
1048                                 is_file = !S_ISLNK(elem->parent[i].mode);
1049                         if (!is_file)
1050                                 elem->mode = canon_mode(S_IFLNK);
1051
1052                         result_size = len;
1053                         result = xmallocz(len);
1054
1055                         done = read_in_full(fd, result, len);
1056                         if (done < 0)
1057                                 die_errno("read error '%s'", elem->path);
1058                         else if (done < len)
1059                                 die("early EOF '%s'", elem->path);
1060
1061                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1062                         if (is_file) {
1063                                 struct strbuf buf = STRBUF_INIT;
1064
1065                                 if (convert_to_git(rev->diffopt.repo->index,
1066                                                    elem->path, result, len, &buf, global_conv_flags_eol)) {
1067                                         free(result);
1068                                         result = strbuf_detach(&buf, &len);
1069                                         result_size = len;
1070                                 }
1071                         }
1072                 }
1073                 else {
1074                 deleted_file:
1075                         result_deleted = 1;
1076                         result_size = 0;
1077                         elem->mode = 0;
1078                         result = xcalloc(1, 1);
1079                 }
1080
1081                 if (0 <= fd)
1082                         close(fd);
1083         }
1084
1085         for (i = 0; i < num_parent; i++) {
1086                 if (elem->parent[i].mode != elem->mode) {
1087                         mode_differs = 1;
1088                         break;
1089                 }
1090         }
1091
1092         if (textconv)
1093                 is_binary = 0;
1094         else if (userdiff->binary != -1)
1095                 is_binary = userdiff->binary;
1096         else {
1097                 is_binary = buffer_is_binary(result, result_size);
1098                 for (i = 0; !is_binary && i < num_parent; i++) {
1099                         char *buf;
1100                         unsigned long size;
1101                         buf = grab_blob(opt->repo,
1102                                         &elem->parent[i].oid,
1103                                         elem->parent[i].mode,
1104                                         &size, NULL, NULL);
1105                         if (buffer_is_binary(buf, size))
1106                                 is_binary = 1;
1107                         free(buf);
1108                 }
1109         }
1110         if (is_binary) {
1111                 show_combined_header(elem, num_parent, dense, rev,
1112                                      line_prefix, mode_differs, 0);
1113                 printf("Binary files differ\n");
1114                 free(result);
1115                 return;
1116         }
1117
1118         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1119                 if (*cp == '\n')
1120                         cnt++;
1121         }
1122         if (result_size && result[result_size-1] != '\n')
1123                 cnt++; /* incomplete line */
1124
1125         sline = xcalloc(st_add(cnt, 2), sizeof(*sline));
1126         sline[0].bol = result;
1127         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1128                 if (*cp == '\n') {
1129                         sline[lno].len = cp - sline[lno].bol;
1130                         lno++;
1131                         if (lno < cnt)
1132                                 sline[lno].bol = cp + 1;
1133                 }
1134         }
1135         if (result_size && result[result_size-1] != '\n')
1136                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1137
1138         result_file.ptr = result;
1139         result_file.size = result_size;
1140
1141         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1142          * for deletion hunk at the end.
1143          */
1144         sline[0].p_lno = xcalloc(st_mult(st_add(cnt, 2), num_parent), sizeof(unsigned long));
1145         for (lno = 0; lno <= cnt; lno++)
1146                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1147
1148         for (i = 0; i < num_parent; i++) {
1149                 int j;
1150                 for (j = 0; j < i; j++) {
1151                         if (oideq(&elem->parent[i].oid,
1152                                   &elem->parent[j].oid)) {
1153                                 reuse_combine_diff(sline, cnt, i, j);
1154                                 break;
1155                         }
1156                 }
1157                 if (i <= j)
1158                         combine_diff(opt->repo,
1159                                      &elem->parent[i].oid,
1160                                      elem->parent[i].mode,
1161                                      &result_file, sline,
1162                                      cnt, i, num_parent, result_deleted,
1163                                      textconv, elem->path, opt->xdl_opts);
1164         }
1165
1166         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1167
1168         if (show_hunks || mode_differs || working_tree_file) {
1169                 show_combined_header(elem, num_parent, dense, rev,
1170                                      line_prefix, mode_differs, 1);
1171                 dump_sline(sline, line_prefix, cnt, num_parent,
1172                            opt->use_color, result_deleted);
1173         }
1174         free(result);
1175
1176         for (lno = 0; lno < cnt; lno++) {
1177                 if (sline[lno].lost) {
1178                         struct lline *ll = sline[lno].lost;
1179                         while (ll) {
1180                                 struct lline *tmp = ll;
1181                                 ll = ll->next;
1182                                 free(tmp);
1183                         }
1184                 }
1185         }
1186         free(sline[0].p_lno);
1187         free(sline);
1188 }
1189
1190 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1191 {
1192         struct diff_options *opt = &rev->diffopt;
1193         int line_termination, inter_name_termination, i;
1194         const char *line_prefix = diff_line_prefix(opt);
1195
1196         line_termination = opt->line_termination;
1197         inter_name_termination = '\t';
1198         if (!line_termination)
1199                 inter_name_termination = 0;
1200
1201         if (rev->loginfo && !rev->no_commit_id)
1202                 show_log(rev);
1203
1204
1205         if (opt->output_format & DIFF_FORMAT_RAW) {
1206                 printf("%s", line_prefix);
1207
1208                 /* As many colons as there are parents */
1209                 for (i = 0; i < num_parent; i++)
1210                         putchar(':');
1211
1212                 /* Show the modes */
1213                 for (i = 0; i < num_parent; i++)
1214                         printf("%06o ", p->parent[i].mode);
1215                 printf("%06o", p->mode);
1216
1217                 /* Show sha1's */
1218                 for (i = 0; i < num_parent; i++)
1219                         printf(" %s", diff_aligned_abbrev(&p->parent[i].oid,
1220                                                           opt->abbrev));
1221                 printf(" %s ", diff_aligned_abbrev(&p->oid, opt->abbrev));
1222         }
1223
1224         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1225                 for (i = 0; i < num_parent; i++)
1226                         putchar(p->parent[i].status);
1227                 putchar(inter_name_termination);
1228         }
1229
1230         write_name_quoted(p->path, stdout, line_termination);
1231 }
1232
1233 /*
1234  * The result (p->elem) is from the working tree and their
1235  * parents are typically from multiple stages during a merge
1236  * (i.e. diff-files) or the state in HEAD and in the index
1237  * (i.e. diff-index).
1238  */
1239 void show_combined_diff(struct combine_diff_path *p,
1240                        int num_parent,
1241                        int dense,
1242                        struct rev_info *rev)
1243 {
1244         struct diff_options *opt = &rev->diffopt;
1245
1246         if (opt->output_format & (DIFF_FORMAT_RAW |
1247                                   DIFF_FORMAT_NAME |
1248                                   DIFF_FORMAT_NAME_STATUS))
1249                 show_raw_diff(p, num_parent, rev);
1250         else if (opt->output_format & DIFF_FORMAT_PATCH)
1251                 show_patch_diff(p, num_parent, dense, 1, rev);
1252 }
1253
1254 static void free_combined_pair(struct diff_filepair *pair)
1255 {
1256         free(pair->two);
1257         free(pair);
1258 }
1259
1260 /*
1261  * A combine_diff_path expresses N parents on the LHS against 1 merge
1262  * result. Synthesize a diff_filepair that has N entries on the "one"
1263  * side and 1 entry on the "two" side.
1264  *
1265  * In the future, we might want to add more data to combine_diff_path
1266  * so that we can fill fields we are ignoring (most notably, size) here,
1267  * but currently nobody uses it, so this should suffice for now.
1268  */
1269 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1270                                            int num_parent)
1271 {
1272         int i;
1273         struct diff_filepair *pair;
1274         struct diff_filespec *pool;
1275
1276         pair = xmalloc(sizeof(*pair));
1277         pool = xcalloc(st_add(num_parent, 1), sizeof(struct diff_filespec));
1278         pair->one = pool + 1;
1279         pair->two = pool;
1280
1281         for (i = 0; i < num_parent; i++) {
1282                 pair->one[i].path = p->path;
1283                 pair->one[i].mode = p->parent[i].mode;
1284                 oidcpy(&pair->one[i].oid, &p->parent[i].oid);
1285                 pair->one[i].oid_valid = !is_null_oid(&p->parent[i].oid);
1286                 pair->one[i].has_more_entries = 1;
1287         }
1288         pair->one[num_parent - 1].has_more_entries = 0;
1289
1290         pair->two->path = p->path;
1291         pair->two->mode = p->mode;
1292         oidcpy(&pair->two->oid, &p->oid);
1293         pair->two->oid_valid = !is_null_oid(&p->oid);
1294         return pair;
1295 }
1296
1297 static void handle_combined_callback(struct diff_options *opt,
1298                                      struct combine_diff_path *paths,
1299                                      int num_parent,
1300                                      int num_paths)
1301 {
1302         struct combine_diff_path *p;
1303         struct diff_queue_struct q;
1304         int i;
1305
1306         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1307         q.alloc = num_paths;
1308         q.nr = num_paths;
1309         for (i = 0, p = paths; p; p = p->next)
1310                 q.queue[i++] = combined_pair(p, num_parent);
1311         opt->format_callback(&q, opt, opt->format_callback_data);
1312         for (i = 0; i < num_paths; i++)
1313                 free_combined_pair(q.queue[i]);
1314         free(q.queue);
1315 }
1316
1317 static const char *path_path(void *obj)
1318 {
1319         struct combine_diff_path *path = (struct combine_diff_path *)obj;
1320
1321         return path->path;
1322 }
1323
1324 /*
1325  * Diff stat formats which we always compute solely against the first parent.
1326  */
1327 #define STAT_FORMAT_MASK (DIFF_FORMAT_NUMSTAT \
1328                           | DIFF_FORMAT_SHORTSTAT \
1329                           | DIFF_FORMAT_SUMMARY \
1330                           | DIFF_FORMAT_DIRSTAT \
1331                           | DIFF_FORMAT_DIFFSTAT)
1332
1333 /* find set of paths that every parent touches */
1334 static struct combine_diff_path *find_paths_generic(const struct object_id *oid,
1335         const struct oid_array *parents, struct diff_options *opt)
1336 {
1337         struct combine_diff_path *paths = NULL;
1338         int i, num_parent = parents->nr;
1339
1340         int output_format = opt->output_format;
1341         const char *orderfile = opt->orderfile;
1342
1343         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1344         /* tell diff_tree to emit paths in sorted (=tree) order */
1345         opt->orderfile = NULL;
1346
1347         /* D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)  (wrt paths) */
1348         for (i = 0; i < num_parent; i++) {
1349                 /*
1350                  * show stat against the first parent even when doing
1351                  * combined diff.
1352                  */
1353                 int stat_opt = output_format & STAT_FORMAT_MASK;
1354                 if (i == 0 && stat_opt)
1355                         opt->output_format = stat_opt;
1356                 else
1357                         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1358                 diff_tree_oid(&parents->oid[i], oid, "", opt);
1359                 diffcore_std(opt);
1360                 paths = intersect_paths(paths, i, num_parent);
1361
1362                 /* if showing diff, show it in requested order */
1363                 if (opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1364                     orderfile) {
1365                         diffcore_order(orderfile);
1366                 }
1367
1368                 diff_flush(opt);
1369         }
1370
1371         opt->output_format = output_format;
1372         opt->orderfile = orderfile;
1373         return paths;
1374 }
1375
1376
1377 /*
1378  * find set of paths that everybody touches, assuming diff is run without
1379  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
1380  */
1381 static struct combine_diff_path *find_paths_multitree(
1382         const struct object_id *oid, const struct oid_array *parents,
1383         struct diff_options *opt)
1384 {
1385         int i, nparent = parents->nr;
1386         const struct object_id **parents_oid;
1387         struct combine_diff_path paths_head;
1388         struct strbuf base;
1389
1390         ALLOC_ARRAY(parents_oid, nparent);
1391         for (i = 0; i < nparent; i++)
1392                 parents_oid[i] = &parents->oid[i];
1393
1394         /* fake list head, so worker can assume it is non-NULL */
1395         paths_head.next = NULL;
1396
1397         strbuf_init(&base, PATH_MAX);
1398         diff_tree_paths(&paths_head, oid, parents_oid, nparent, &base, opt);
1399
1400         strbuf_release(&base);
1401         free(parents_oid);
1402         return paths_head.next;
1403 }
1404
1405
1406 void diff_tree_combined(const struct object_id *oid,
1407                         const struct oid_array *parents,
1408                         int dense,
1409                         struct rev_info *rev)
1410 {
1411         struct diff_options *opt = &rev->diffopt;
1412         struct diff_options diffopts;
1413         struct combine_diff_path *p, *paths;
1414         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1415         int need_generic_pathscan;
1416
1417         /* nothing to do, if no parents */
1418         if (!num_parent)
1419                 return;
1420
1421         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1422         needsep = 0;
1423         if (show_log_first) {
1424                 show_log(rev);
1425
1426                 if (rev->verbose_header && opt->output_format &&
1427                     opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1428                     !commit_format_is_empty(rev->commit_format))
1429                         printf("%s%c", diff_line_prefix(opt),
1430                                opt->line_termination);
1431         }
1432
1433         diffopts = *opt;
1434         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1435         diffopts.flags.recursive = 1;
1436         diffopts.flags.allow_external = 0;
1437
1438         /* find set of paths that everybody touches
1439          *
1440          * NOTE
1441          *
1442          * Diffcore transformations are bound to diff_filespec and logic
1443          * comparing two entries - i.e. they do not apply directly to combine
1444          * diff.
1445          *
1446          * If some of such transformations is requested - we launch generic
1447          * path scanning, which works significantly slower compared to
1448          * simultaneous all-trees-in-one-go scan in find_paths_multitree().
1449          *
1450          * TODO some of the filters could be ported to work on
1451          * combine_diff_paths - i.e. all functionality that skips paths, so in
1452          * theory, we could end up having only multitree path scanning.
1453          *
1454          * NOTE please keep this semantically in sync with diffcore_std()
1455          */
1456         need_generic_pathscan = opt->skip_stat_unmatch  ||
1457                         opt->flags.follow_renames       ||
1458                         opt->break_opt != -1    ||
1459                         opt->detect_rename      ||
1460                         (opt->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)   ||
1461                         opt->filter;
1462
1463
1464         if (need_generic_pathscan) {
1465                 /*
1466                  * NOTE generic case also handles --stat, as it computes
1467                  * diff(sha1,parent_i) for all i to do the job, specifically
1468                  * for parent0.
1469                  */
1470                 paths = find_paths_generic(oid, parents, &diffopts);
1471         }
1472         else {
1473                 int stat_opt;
1474                 paths = find_paths_multitree(oid, parents, &diffopts);
1475
1476                 /*
1477                  * show stat against the first parent even
1478                  * when doing combined diff.
1479                  */
1480                 stat_opt = opt->output_format & STAT_FORMAT_MASK;
1481                 if (stat_opt) {
1482                         diffopts.output_format = stat_opt;
1483
1484                         diff_tree_oid(&parents->oid[0], oid, "", &diffopts);
1485                         diffcore_std(&diffopts);
1486                         if (opt->orderfile)
1487                                 diffcore_order(opt->orderfile);
1488                         diff_flush(&diffopts);
1489                 }
1490         }
1491
1492         /* find out number of surviving paths */
1493         for (num_paths = 0, p = paths; p; p = p->next)
1494                 num_paths++;
1495
1496         /* order paths according to diffcore_order */
1497         if (opt->orderfile && num_paths) {
1498                 struct obj_order *o;
1499
1500                 ALLOC_ARRAY(o, num_paths);
1501                 for (i = 0, p = paths; p; p = p->next, i++)
1502                         o[i].obj = p;
1503                 order_objects(opt->orderfile, path_path, o, num_paths);
1504                 for (i = 0; i < num_paths - 1; i++) {
1505                         p = o[i].obj;
1506                         p->next = o[i+1].obj;
1507                 }
1508
1509                 p = o[num_paths-1].obj;
1510                 p->next = NULL;
1511                 paths = o[0].obj;
1512                 free(o);
1513         }
1514
1515
1516         if (num_paths) {
1517                 if (opt->output_format & (DIFF_FORMAT_RAW |
1518                                           DIFF_FORMAT_NAME |
1519                                           DIFF_FORMAT_NAME_STATUS)) {
1520                         for (p = paths; p; p = p->next)
1521                                 show_raw_diff(p, num_parent, rev);
1522                         needsep = 1;
1523                 }
1524                 else if (opt->output_format & STAT_FORMAT_MASK)
1525                         needsep = 1;
1526                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1527                         handle_combined_callback(opt, paths, num_parent, num_paths);
1528
1529                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1530                         if (needsep)
1531                                 printf("%s%c", diff_line_prefix(opt),
1532                                        opt->line_termination);
1533                         for (p = paths; p; p = p->next)
1534                                 show_patch_diff(p, num_parent, dense,
1535                                                 0, rev);
1536                 }
1537         }
1538
1539         /* Clean things up */
1540         while (paths) {
1541                 struct combine_diff_path *tmp = paths;
1542                 paths = paths->next;
1543                 free(tmp);
1544         }
1545
1546         clear_pathspec(&diffopts.pathspec);
1547 }
1548
1549 void diff_tree_combined_merge(const struct commit *commit, int dense,
1550                               struct rev_info *rev)
1551 {
1552         struct commit_list *parent = get_saved_parents(rev, commit);
1553         struct oid_array parents = OID_ARRAY_INIT;
1554
1555         while (parent) {
1556                 oid_array_append(&parents, &parent->item->object.oid);
1557                 parent = parent->next;
1558         }
1559         diff_tree_combined(&commit->object.oid, &parents, dense, rev);
1560         oid_array_clear(&parents);
1561 }