French translation: copy -> copie.
[git/dscho.git] / xdiff / xmerge.c
blob9e13b25abc90350de4488276074dc282edc216b1
1 /*
2  *  LibXDiff by Davide Libenzi ( File Differential Library )
3  *  Copyright (C) 2003-2006 Davide Libenzi, Johannes E. Schindelin
4  *
5  *  This library is free software; you can redistribute it and/or
6  *  modify it under the terms of the GNU Lesser General Public
7  *  License as published by the Free Software Foundation; either
8  *  version 2.1 of the License, or (at your option) any later version.
9  *
10  *  This library is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  *  Lesser General Public License for more details.
14  *
15  *  You should have received a copy of the GNU Lesser General Public
16  *  License along with this library; if not, write to the Free Software
17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  *
19  *  Davide Libenzi <davidel@xmailserver.org>
20  *
21  */
23 #include "xinclude.h"
25 typedef struct s_xdmerge {
26         struct s_xdmerge *next;
27         /*
28          * 0 = conflict,
29          * 1 = no conflict, take first,
30          * 2 = no conflict, take second.
31          * 3 = no conflict, take both.
32          */
33         int mode;
34         /*
35          * These point at the respective postimages.  E.g. <i1,chg1> is
36          * how side #1 wants to change the common ancestor; if there is no
37          * overlap, lines before i1 in the postimage of side #1 appear
38          * in the merge result as a region touched by neither side.
39          */
40         long i1, i2;
41         long chg1, chg2;
42         /*
43          * These point at the preimage; of course there is just one
44          * preimage, that is from the shared common ancestor.
45          */
46         long i0;
47         long chg0;
48 } xdmerge_t;
50 static int xdl_append_merge(xdmerge_t **merge, int mode,
51                             long i0, long chg0,
52                             long i1, long chg1,
53                             long i2, long chg2)
55         xdmerge_t *m = *merge;
56         if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
57                 if (mode != m->mode)
58                         m->mode = 0;
59                 m->chg0 = i0 + chg0 - m->i0;
60                 m->chg1 = i1 + chg1 - m->i1;
61                 m->chg2 = i2 + chg2 - m->i2;
62         } else {
63                 m = xdl_malloc(sizeof(xdmerge_t));
64                 if (!m)
65                         return -1;
66                 m->next = NULL;
67                 m->mode = mode;
68                 m->i0 = i0;
69                 m->chg0 = chg0;
70                 m->i1 = i1;
71                 m->chg1 = chg1;
72                 m->i2 = i2;
73                 m->chg2 = chg2;
74                 if (*merge)
75                         (*merge)->next = m;
76                 *merge = m;
77         }
78         return 0;
81 static int xdl_cleanup_merge(xdmerge_t *c)
83         int count = 0;
84         xdmerge_t *next_c;
86         /* were there conflicts? */
87         for (; c; c = next_c) {
88                 if (c->mode == 0)
89                         count++;
90                 next_c = c->next;
91                 free(c);
92         }
93         return count;
96 static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
97                 int line_count, long flags)
99         int i;
100         xrecord_t **rec1 = xe1->xdf2.recs + i1;
101         xrecord_t **rec2 = xe2->xdf2.recs + i2;
103         for (i = 0; i < line_count; i++) {
104                 int result = xdl_recmatch(rec1[i]->ptr, rec1[i]->size,
105                         rec2[i]->ptr, rec2[i]->size, flags);
106                 if (!result)
107                         return -1;
108         }
109         return 0;
112 static int xdl_recs_copy_0(int use_orig, xdfenv_t *xe, int i, int count, int add_nl, char *dest)
114         xrecord_t **recs;
115         int size = 0;
117         recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
119         if (count < 1)
120                 return 0;
122         for (i = 0; i < count; size += recs[i++]->size)
123                 if (dest)
124                         memcpy(dest + size, recs[i]->ptr, recs[i]->size);
125         if (add_nl) {
126                 i = recs[count - 1]->size;
127                 if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
128                         if (dest)
129                                 dest[size] = '\n';
130                         size++;
131                 }
132         }
133         return size;
136 static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
138         return xdl_recs_copy_0(0, xe, i, count, add_nl, dest);
141 static int xdl_orig_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
143         return xdl_recs_copy_0(1, xe, i, count, add_nl, dest);
146 static int fill_conflict_hunk(xdfenv_t *xe1, const char *name1,
147                               xdfenv_t *xe2, const char *name2,
148                               const char *name3,
149                               int size, int i, int style,
150                               xdmerge_t *m, char *dest, int marker_size)
152         int marker1_size = (name1 ? strlen(name1) + 1 : 0);
153         int marker2_size = (name2 ? strlen(name2) + 1 : 0);
154         int marker3_size = (name3 ? strlen(name3) + 1 : 0);
156         if (marker_size <= 0)
157                 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
159         /* Before conflicting part */
160         size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
161                               dest ? dest + size : NULL);
163         if (!dest) {
164                 size += marker_size + 1 + marker1_size;
165         } else {
166                 memset(dest + size, '<', marker_size);
167                 size += marker_size;
168                 if (marker1_size) {
169                         dest[size] = ' ';
170                         memcpy(dest + size + 1, name1, marker1_size - 1);
171                         size += marker1_size;
172                 }
173                 dest[size++] = '\n';
174         }
176         /* Postimage from side #1 */
177         size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
178                               dest ? dest + size : NULL);
180         if (style == XDL_MERGE_DIFF3) {
181                 /* Shared preimage */
182                 if (!dest) {
183                         size += marker_size + 1 + marker3_size;
184                 } else {
185                         memset(dest + size, '|', marker_size);
186                         size += marker_size;
187                         if (marker3_size) {
188                                 dest[size] = ' ';
189                                 memcpy(dest + size + 1, name3, marker3_size - 1);
190                                 size += marker3_size;
191                         }
192                         dest[size++] = '\n';
193                 }
194                 size += xdl_orig_copy(xe1, m->i0, m->chg0, 1,
195                                       dest ? dest + size : NULL);
196         }
198         if (!dest) {
199                 size += marker_size + 1;
200         } else {
201                 memset(dest + size, '=', marker_size);
202                 size += marker_size;
203                 dest[size++] = '\n';
204         }
206         /* Postimage from side #2 */
207         size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
208                               dest ? dest + size : NULL);
209         if (!dest) {
210                 size += marker_size + 1 + marker2_size;
211         } else {
212                 memset(dest + size, '>', marker_size);
213                 size += marker_size;
214                 if (marker2_size) {
215                         dest[size] = ' ';
216                         memcpy(dest + size + 1, name2, marker2_size - 1);
217                         size += marker2_size;
218                 }
219                 dest[size++] = '\n';
220         }
221         return size;
224 static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
225                                  xdfenv_t *xe2, const char *name2,
226                                  const char *ancestor_name,
227                                  int favor,
228                                  xdmerge_t *m, char *dest, int style,
229                                  int marker_size)
231         int size, i;
233         for (size = i = 0; m; m = m->next) {
234                 if (favor && !m->mode)
235                         m->mode = favor;
237                 if (m->mode == 0)
238                         size = fill_conflict_hunk(xe1, name1, xe2, name2,
239                                                   ancestor_name,
240                                                   size, i, style, m, dest,
241                                                   marker_size);
242                 else if (m->mode & 3) {
243                         /* Before conflicting part */
244                         size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
245                                               dest ? dest + size : NULL);
246                         /* Postimage from side #1 */
247                         if (m->mode & 1)
248                                 size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
249                                                       dest ? dest + size : NULL);
250                         /* Postimage from side #2 */
251                         if (m->mode & 2)
252                                 size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
253                                                       dest ? dest + size : NULL);
254                 } else
255                         continue;
256                 i = m->i1 + m->chg1;
257         }
258         size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0,
259                               dest ? dest + size : NULL);
260         return size;
264  * Sometimes, changes are not quite identical, but differ in only a few
265  * lines. Try hard to show only these few lines as conflicting.
266  */
267 static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
268                 xpparam_t const *xpp)
270         for (; m; m = m->next) {
271                 mmfile_t t1, t2;
272                 xdfenv_t xe;
273                 xdchange_t *xscr, *x;
274                 int i1 = m->i1, i2 = m->i2;
276                 /* let's handle just the conflicts */
277                 if (m->mode)
278                         continue;
280                 /* no sense refining a conflict when one side is empty */
281                 if (m->chg1 == 0 || m->chg2 == 0)
282                         continue;
284                 /*
285                  * This probably does not work outside git, since
286                  * we have a very simple mmfile structure.
287                  */
288                 t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
289                 t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
290                         + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
291                 t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
292                 t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
293                         + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
294                 if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
295                         return -1;
296                 if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
297                     xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
298                     xdl_build_script(&xe, &xscr) < 0) {
299                         xdl_free_env(&xe);
300                         return -1;
301                 }
302                 if (!xscr) {
303                         /* If this happens, the changes are identical. */
304                         xdl_free_env(&xe);
305                         m->mode = 4;
306                         continue;
307                 }
308                 x = xscr;
309                 m->i1 = xscr->i1 + i1;
310                 m->chg1 = xscr->chg1;
311                 m->i2 = xscr->i2 + i2;
312                 m->chg2 = xscr->chg2;
313                 while (xscr->next) {
314                         xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
315                         if (!m2) {
316                                 xdl_free_env(&xe);
317                                 xdl_free_script(x);
318                                 return -1;
319                         }
320                         xscr = xscr->next;
321                         m2->next = m->next;
322                         m->next = m2;
323                         m = m2;
324                         m->mode = 0;
325                         m->i1 = xscr->i1 + i1;
326                         m->chg1 = xscr->chg1;
327                         m->i2 = xscr->i2 + i2;
328                         m->chg2 = xscr->chg2;
329                 }
330                 xdl_free_env(&xe);
331                 xdl_free_script(x);
332         }
333         return 0;
336 static int line_contains_alnum(const char *ptr, long size)
338         while (size--)
339                 if (isalnum((unsigned char)*(ptr++)))
340                         return 1;
341         return 0;
344 static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
346         for (; chg; chg--, i++)
347                 if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
348                                 xe->xdf2.recs[i]->size))
349                         return 1;
350         return 0;
354  * This function merges m and m->next, marking everything between those hunks
355  * as conflicting, too.
356  */
357 static void xdl_merge_two_conflicts(xdmerge_t *m)
359         xdmerge_t *next_m = m->next;
360         m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
361         m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
362         m->next = next_m->next;
363         free(next_m);
367  * If there are less than 3 non-conflicting lines between conflicts,
368  * it appears simpler -- because it takes up less (or as many) lines --
369  * if the lines are moved into the conflicts.
370  */
371 static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
372                                       int simplify_if_no_alnum)
374         int result = 0;
376         if (!m)
377                 return result;
378         for (;;) {
379                 xdmerge_t *next_m = m->next;
380                 int begin, end;
382                 if (!next_m)
383                         return result;
385                 begin = m->i1 + m->chg1;
386                 end = next_m->i1;
388                 if (m->mode != 0 || next_m->mode != 0 ||
389                     (end - begin > 3 &&
390                      (!simplify_if_no_alnum ||
391                       lines_contain_alnum(xe1, begin, end - begin)))) {
392                         m = next_m;
393                 } else {
394                         result++;
395                         xdl_merge_two_conflicts(m);
396                 }
397         }
401  * level == 0: mark all overlapping changes as conflict
402  * level == 1: mark overlapping changes as conflict only if not identical
403  * level == 2: analyze non-identical changes for minimal conflict set
404  * level == 3: analyze non-identical changes for minimal conflict set, but
405  *             treat hunks not containing any letter or number as conflicting
407  * returns < 0 on error, == 0 for no conflicts, else number of conflicts
408  */
409 static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
410                 xdfenv_t *xe2, xdchange_t *xscr2,
411                 xmparam_t const *xmp, mmbuffer_t *result)
413         xdmerge_t *changes, *c;
414         xpparam_t const *xpp = &xmp->xpp;
415         const char *const ancestor_name = xmp->ancestor;
416         const char *const name1 = xmp->file1;
417         const char *const name2 = xmp->file2;
418         int i0, i1, i2, chg0, chg1, chg2;
419         int level = xmp->level;
420         int style = xmp->style;
421         int favor = xmp->favor;
423         if (style == XDL_MERGE_DIFF3) {
424                 /*
425                  * "diff3 -m" output does not make sense for anything
426                  * more aggressive than XDL_MERGE_EAGER.
427                  */
428                 if (XDL_MERGE_EAGER < level)
429                         level = XDL_MERGE_EAGER;
430         }
432         c = changes = NULL;
434         while (xscr1 && xscr2) {
435                 if (!changes)
436                         changes = c;
437                 if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
438                         i0 = xscr1->i1;
439                         i1 = xscr1->i2;
440                         i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
441                         chg0 = xscr1->chg1;
442                         chg1 = xscr1->chg2;
443                         chg2 = xscr1->chg1;
444                         if (xdl_append_merge(&c, 1,
445                                              i0, chg0, i1, chg1, i2, chg2)) {
446                                 xdl_cleanup_merge(changes);
447                                 return -1;
448                         }
449                         xscr1 = xscr1->next;
450                         continue;
451                 }
452                 if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
453                         i0 = xscr2->i1;
454                         i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
455                         i2 = xscr2->i2;
456                         chg0 = xscr2->chg1;
457                         chg1 = xscr2->chg1;
458                         chg2 = xscr2->chg2;
459                         if (xdl_append_merge(&c, 2,
460                                              i0, chg0, i1, chg1, i2, chg2)) {
461                                 xdl_cleanup_merge(changes);
462                                 return -1;
463                         }
464                         xscr2 = xscr2->next;
465                         continue;
466                 }
467                 if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
468                                 xscr1->chg1 != xscr2->chg1 ||
469                                 xscr1->chg2 != xscr2->chg2 ||
470                                 xdl_merge_cmp_lines(xe1, xscr1->i2,
471                                         xe2, xscr2->i2,
472                                         xscr1->chg2, xpp->flags)) {
473                         /* conflict */
474                         int off = xscr1->i1 - xscr2->i1;
475                         int ffo = off + xscr1->chg1 - xscr2->chg1;
477                         i0 = xscr1->i1;
478                         i1 = xscr1->i2;
479                         i2 = xscr2->i2;
480                         if (off > 0) {
481                                 i0 -= off;
482                                 i1 -= off;
483                         }
484                         else
485                                 i2 += off;
486                         chg0 = xscr1->i1 + xscr1->chg1 - i0;
487                         chg1 = xscr1->i2 + xscr1->chg2 - i1;
488                         chg2 = xscr2->i2 + xscr2->chg2 - i2;
489                         if (ffo < 0) {
490                                 chg0 -= ffo;
491                                 chg1 -= ffo;
492                         } else
493                                 chg2 += ffo;
494                         if (xdl_append_merge(&c, 0,
495                                              i0, chg0, i1, chg1, i2, chg2)) {
496                                 xdl_cleanup_merge(changes);
497                                 return -1;
498                         }
499                 }
501                 i1 = xscr1->i1 + xscr1->chg1;
502                 i2 = xscr2->i1 + xscr2->chg1;
504                 if (i1 >= i2)
505                         xscr2 = xscr2->next;
506                 if (i2 >= i1)
507                         xscr1 = xscr1->next;
508         }
509         while (xscr1) {
510                 if (!changes)
511                         changes = c;
512                 i0 = xscr1->i1;
513                 i1 = xscr1->i2;
514                 i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
515                 chg0 = xscr1->chg1;
516                 chg1 = xscr1->chg2;
517                 chg2 = xscr1->chg1;
518                 if (xdl_append_merge(&c, 1,
519                                      i0, chg0, i1, chg1, i2, chg2)) {
520                         xdl_cleanup_merge(changes);
521                         return -1;
522                 }
523                 xscr1 = xscr1->next;
524         }
525         while (xscr2) {
526                 if (!changes)
527                         changes = c;
528                 i0 = xscr2->i1;
529                 i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
530                 i2 = xscr2->i2;
531                 chg0 = xscr2->chg1;
532                 chg1 = xscr2->chg1;
533                 chg2 = xscr2->chg2;
534                 if (xdl_append_merge(&c, 2,
535                                      i0, chg0, i1, chg1, i2, chg2)) {
536                         xdl_cleanup_merge(changes);
537                         return -1;
538                 }
539                 xscr2 = xscr2->next;
540         }
541         if (!changes)
542                 changes = c;
543         /* refine conflicts */
544         if (XDL_MERGE_ZEALOUS <= level &&
545             (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
546              xdl_simplify_non_conflicts(xe1, changes,
547                                         XDL_MERGE_ZEALOUS < level) < 0)) {
548                 xdl_cleanup_merge(changes);
549                 return -1;
550         }
551         /* output */
552         if (result) {
553                 int marker_size = xmp->marker_size;
554                 int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
555                                                  ancestor_name,
556                                                  favor, changes, NULL, style,
557                                                  marker_size);
558                 result->ptr = xdl_malloc(size);
559                 if (!result->ptr) {
560                         xdl_cleanup_merge(changes);
561                         return -1;
562                 }
563                 result->size = size;
564                 xdl_fill_merge_buffer(xe1, name1, xe2, name2,
565                                       ancestor_name, favor, changes,
566                                       result->ptr, style, marker_size);
567         }
568         return xdl_cleanup_merge(changes);
571 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
572                 xmparam_t const *xmp, mmbuffer_t *result)
574         xdchange_t *xscr1, *xscr2;
575         xdfenv_t xe1, xe2;
576         int status;
577         xpparam_t const *xpp = &xmp->xpp;
579         result->ptr = NULL;
580         result->size = 0;
582         if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
583                         xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
584                 return -1;
585         }
586         if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
587             xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
588             xdl_build_script(&xe1, &xscr1) < 0) {
589                 xdl_free_env(&xe1);
590                 return -1;
591         }
592         if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
593             xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
594             xdl_build_script(&xe2, &xscr2) < 0) {
595                 xdl_free_env(&xe2);
596                 return -1;
597         }
598         status = 0;
599         if (!xscr1) {
600                 result->ptr = xdl_malloc(mf2->size);
601                 memcpy(result->ptr, mf2->ptr, mf2->size);
602                 result->size = mf2->size;
603         } else if (!xscr2) {
604                 result->ptr = xdl_malloc(mf1->size);
605                 memcpy(result->ptr, mf1->ptr, mf1->size);
606                 result->size = mf1->size;
607         } else {
608                 status = xdl_do_merge(&xe1, xscr1,
609                                       &xe2, xscr2,
610                                       xmp, result);
611         }
612         xdl_free_script(xscr1);
613         xdl_free_script(xscr2);
615         xdl_free_env(&xe1);
616         xdl_free_env(&xe2);
618         return status;