Add --verbose|-v to test-chmtime
[git/dscho.git] / xdiff / xmerge.c
blob82b3573e7ada8c6df13ac24a78650b80af91ea73
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          */
32         int mode;
33         long i1, i2;
34         long chg1, chg2;
35 } xdmerge_t;
37 static int xdl_append_merge(xdmerge_t **merge, int mode,
38                 long i1, long chg1, long i2, long chg2)
40         xdmerge_t *m = *merge;
41         if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
42                 if (mode != m->mode)
43                         m->mode = 0;
44                 m->chg1 = i1 + chg1 - m->i1;
45                 m->chg2 = i2 + chg2 - m->i2;
46         } else {
47                 m = xdl_malloc(sizeof(xdmerge_t));
48                 if (!m)
49                         return -1;
50                 m->next = NULL;
51                 m->mode = mode;
52                 m->i1 = i1;
53                 m->chg1 = chg1;
54                 m->i2 = i2;
55                 m->chg2 = chg2;
56                 if (*merge)
57                         (*merge)->next = m;
58                 *merge = m;
59         }
60         return 0;
63 static int xdl_cleanup_merge(xdmerge_t *c)
65         int count = 0;
66         xdmerge_t *next_c;
68         /* were there conflicts? */
69         for (; c; c = next_c) {
70                 if (c->mode == 0)
71                         count++;
72                 next_c = c->next;
73                 free(c);
74         }
75         return count;
78 static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
79                 int line_count, long flags)
81         int i;
82         xrecord_t **rec1 = xe1->xdf2.recs + i1;
83         xrecord_t **rec2 = xe2->xdf2.recs + i2;
85         for (i = 0; i < line_count; i++) {
86                 int result = xdl_recmatch(rec1[i]->ptr, rec1[i]->size,
87                         rec2[i]->ptr, rec2[i]->size, flags);
88                 if (!result)
89                         return -1;
90         }
91         return 0;
94 static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
96         xrecord_t **recs = xe->xdf2.recs + i;
97         int size = 0;
99         if (count < 1)
100                 return 0;
102         for (i = 0; i < count; size += recs[i++]->size)
103                 if (dest)
104                         memcpy(dest + size, recs[i]->ptr, recs[i]->size);
105         if (add_nl) {
106                 i = recs[count - 1]->size;
107                 if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
108                         if (dest)
109                                 dest[size] = '\n';
110                         size++;
111                 }
112         }
113         return size;
116 static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
117                 xdfenv_t *xe2, const char *name2, xdmerge_t *m, char *dest)
119         const int marker_size = 7;
120         int marker1_size = (name1 ? strlen(name1) + 1 : 0);
121         int marker2_size = (name2 ? strlen(name2) + 1 : 0);
122         int conflict_marker_size = 3 * (marker_size + 1)
123                 + marker1_size + marker2_size;
124         int size, i1, j;
126         for (size = i1 = 0; m; m = m->next) {
127                 if (m->mode == 0) {
128                         size += xdl_recs_copy(xe1, i1, m->i1 - i1, 0,
129                                         dest ? dest + size : NULL);
130                         if (dest) {
131                                 for (j = 0; j < marker_size; j++)
132                                         dest[size++] = '<';
133                                 if (marker1_size) {
134                                         dest[size] = ' ';
135                                         memcpy(dest + size + 1, name1,
136                                                         marker1_size - 1);
137                                         size += marker1_size;
138                                 }
139                                 dest[size++] = '\n';
140                         } else
141                                 size += conflict_marker_size;
142                         size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
143                                         dest ? dest + size : NULL);
144                         if (dest) {
145                                 for (j = 0; j < marker_size; j++)
146                                         dest[size++] = '=';
147                                 dest[size++] = '\n';
148                         }
149                         size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
150                                         dest ? dest + size : NULL);
151                         if (dest) {
152                                 for (j = 0; j < marker_size; j++)
153                                         dest[size++] = '>';
154                                 if (marker2_size) {
155                                         dest[size] = ' ';
156                                         memcpy(dest + size + 1, name2,
157                                                         marker2_size - 1);
158                                         size += marker2_size;
159                                 }
160                                 dest[size++] = '\n';
161                         }
162                 } else if (m->mode == 1)
163                         size += xdl_recs_copy(xe1, i1, m->i1 + m->chg1 - i1, 0,
164                                         dest ? dest + size : NULL);
165                 else if (m->mode == 2)
166                         size += xdl_recs_copy(xe2, m->i2 - m->i1 + i1,
167                                         m->i1 + m->chg2 - i1, 0,
168                                         dest ? dest + size : NULL);
169                 else
170                         continue;
171                 i1 = m->i1 + m->chg1;
172         }
173         size += xdl_recs_copy(xe1, i1, xe1->xdf2.nrec - i1, 0,
174                         dest ? dest + size : NULL);
175         return size;
179  * Sometimes, changes are not quite identical, but differ in only a few
180  * lines. Try hard to show only these few lines as conflicting.
181  */
182 static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
183                 xpparam_t const *xpp)
185         for (; m; m = m->next) {
186                 mmfile_t t1, t2;
187                 xdfenv_t xe;
188                 xdchange_t *xscr, *x;
189                 int i1 = m->i1, i2 = m->i2;
191                 /* let's handle just the conflicts */
192                 if (m->mode)
193                         continue;
195                 /* no sense refining a conflict when one side is empty */
196                 if (m->chg1 == 0 || m->chg2 == 0)
197                         continue;
199                 /*
200                  * This probably does not work outside git, since
201                  * we have a very simple mmfile structure.
202                  */
203                 t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
204                 t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
205                         + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
206                 t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
207                 t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
208                         + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
209                 if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
210                         return -1;
211                 if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
212                     xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
213                     xdl_build_script(&xe, &xscr) < 0) {
214                         xdl_free_env(&xe);
215                         return -1;
216                 }
217                 if (!xscr) {
218                         /* If this happens, the changes are identical. */
219                         xdl_free_env(&xe);
220                         m->mode = 4;
221                         continue;
222                 }
223                 x = xscr;
224                 m->i1 = xscr->i1 + i1;
225                 m->chg1 = xscr->chg1;
226                 m->i2 = xscr->i2 + i2;
227                 m->chg2 = xscr->chg2;
228                 while (xscr->next) {
229                         xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
230                         if (!m2) {
231                                 xdl_free_env(&xe);
232                                 xdl_free_script(x);
233                                 return -1;
234                         }
235                         xscr = xscr->next;
236                         m2->next = m->next;
237                         m->next = m2;
238                         m = m2;
239                         m->mode = 0;
240                         m->i1 = xscr->i1 + i1;
241                         m->chg1 = xscr->chg1;
242                         m->i2 = xscr->i2 + i2;
243                         m->chg2 = xscr->chg2;
244                 }
245                 xdl_free_env(&xe);
246                 xdl_free_script(x);
247         }
248         return 0;
251 static int line_contains_alnum(const char *ptr, long size)
253         while (size--)
254                 if (isalnum(*(ptr++)))
255                         return 1;
256         return 0;
259 static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
261         for (; chg; chg--, i++)
262                 if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
263                                 xe->xdf2.recs[i]->size))
264                         return 1;
265         return 0;
269  * This function merges m and m->next, marking everything between those hunks
270  * as conflicting, too.
271  */
272 static void xdl_merge_two_conflicts(xdmerge_t *m)
274         xdmerge_t *next_m = m->next;
275         m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
276         m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
277         m->next = next_m->next;
278         free(next_m);
282  * If there are less than 3 non-conflicting lines between conflicts,
283  * it appears simpler -- because it takes up less (or as many) lines --
284  * if the lines are moved into the conflicts.
285  */
286 static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
287                                       int simplify_if_no_alnum)
289         int result = 0;
291         if (!m)
292                 return result;
293         for (;;) {
294                 xdmerge_t *next_m = m->next;
295                 int begin, end;
297                 if (!next_m)
298                         return result;
300                 begin = m->i1 + m->chg1;
301                 end = next_m->i1;
303                 if (m->mode != 0 || next_m->mode != 0 ||
304                     (end - begin > 3 &&
305                      (!simplify_if_no_alnum ||
306                       lines_contain_alnum(xe1, begin, end - begin)))) {
307                         m = next_m;
308                 } else {
309                         result++;
310                         xdl_merge_two_conflicts(m);
311                 }
312         }
316  * level == 0: mark all overlapping changes as conflict
317  * level == 1: mark overlapping changes as conflict only if not identical
318  * level == 2: analyze non-identical changes for minimal conflict set
319  * level == 3: analyze non-identical changes for minimal conflict set, but
320  *             treat hunks not containing any letter or number as conflicting
322  * returns < 0 on error, == 0 for no conflicts, else number of conflicts
323  */
324 static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1, const char *name1,
325                 xdfenv_t *xe2, xdchange_t *xscr2, const char *name2,
326                 int level, xpparam_t const *xpp, mmbuffer_t *result) {
327         xdmerge_t *changes, *c;
328         int i1, i2, chg1, chg2;
330         c = changes = NULL;
332         while (xscr1 && xscr2) {
333                 if (!changes)
334                         changes = c;
335                 if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
336                         i1 = xscr1->i2;
337                         i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
338                         chg1 = xscr1->chg2;
339                         chg2 = xscr1->chg1;
340                         if (xdl_append_merge(&c, 1, i1, chg1, i2, chg2)) {
341                                 xdl_cleanup_merge(changes);
342                                 return -1;
343                         }
344                         xscr1 = xscr1->next;
345                         continue;
346                 }
347                 if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
348                         i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
349                         i2 = xscr2->i2;
350                         chg1 = xscr2->chg1;
351                         chg2 = xscr2->chg2;
352                         if (xdl_append_merge(&c, 2, i1, chg1, i2, chg2)) {
353                                 xdl_cleanup_merge(changes);
354                                 return -1;
355                         }
356                         xscr2 = xscr2->next;
357                         continue;
358                 }
359                 if (level < 1 || xscr1->i1 != xscr2->i1 ||
360                                 xscr1->chg1 != xscr2->chg1 ||
361                                 xscr1->chg2 != xscr2->chg2 ||
362                                 xdl_merge_cmp_lines(xe1, xscr1->i2,
363                                         xe2, xscr2->i2,
364                                         xscr1->chg2, xpp->flags)) {
365                         /* conflict */
366                         int off = xscr1->i1 - xscr2->i1;
367                         int ffo = off + xscr1->chg1 - xscr2->chg1;
369                         i1 = xscr1->i2;
370                         i2 = xscr2->i2;
371                         if (off > 0)
372                                 i1 -= off;
373                         else
374                                 i2 += off;
375                         chg1 = xscr1->i2 + xscr1->chg2 - i1;
376                         chg2 = xscr2->i2 + xscr2->chg2 - i2;
377                         if (ffo > 0)
378                                 chg2 += ffo;
379                         else
380                                 chg1 -= ffo;
381                         if (xdl_append_merge(&c, 0, i1, chg1, i2, chg2)) {
382                                 xdl_cleanup_merge(changes);
383                                 return -1;
384                         }
385                 }
387                 i1 = xscr1->i1 + xscr1->chg1;
388                 i2 = xscr2->i1 + xscr2->chg1;
390                 if (i1 >= i2)
391                         xscr2 = xscr2->next;
392                 if (i2 >= i1)
393                         xscr1 = xscr1->next;
394         }
395         while (xscr1) {
396                 if (!changes)
397                         changes = c;
398                 i1 = xscr1->i2;
399                 i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
400                 chg1 = xscr1->chg2;
401                 chg2 = xscr1->chg1;
402                 if (xdl_append_merge(&c, 1, i1, chg1, i2, chg2)) {
403                         xdl_cleanup_merge(changes);
404                         return -1;
405                 }
406                 xscr1 = xscr1->next;
407         }
408         while (xscr2) {
409                 if (!changes)
410                         changes = c;
411                 i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
412                 i2 = xscr2->i2;
413                 chg1 = xscr2->chg1;
414                 chg2 = xscr2->chg2;
415                 if (xdl_append_merge(&c, 2, i1, chg1, i2, chg2)) {
416                         xdl_cleanup_merge(changes);
417                         return -1;
418                 }
419                 xscr2 = xscr2->next;
420         }
421         if (!changes)
422                 changes = c;
423         /* refine conflicts */
424         if (level > 1 &&
425             (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
426              xdl_simplify_non_conflicts(xe1, changes, level > 2) < 0)) {
427                 xdl_cleanup_merge(changes);
428                 return -1;
429         }
430         /* output */
431         if (result) {
432                 int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
433                         changes, NULL);
434                 result->ptr = xdl_malloc(size);
435                 if (!result->ptr) {
436                         xdl_cleanup_merge(changes);
437                         return -1;
438                 }
439                 result->size = size;
440                 xdl_fill_merge_buffer(xe1, name1, xe2, name2, changes,
441                                 result->ptr);
442         }
443         return xdl_cleanup_merge(changes);
446 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, const char *name1,
447                 mmfile_t *mf2, const char *name2,
448                 xpparam_t const *xpp, int level, mmbuffer_t *result) {
449         xdchange_t *xscr1, *xscr2;
450         xdfenv_t xe1, xe2;
451         int status;
453         result->ptr = NULL;
454         result->size = 0;
456         if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
457                         xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
458                 return -1;
459         }
460         if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
461             xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
462             xdl_build_script(&xe1, &xscr1) < 0) {
463                 xdl_free_env(&xe1);
464                 return -1;
465         }
466         if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
467             xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
468             xdl_build_script(&xe2, &xscr2) < 0) {
469                 xdl_free_env(&xe2);
470                 return -1;
471         }
472         status = 0;
473         if (xscr1 || xscr2) {
474                 if (!xscr1) {
475                         result->ptr = xdl_malloc(mf2->size);
476                         memcpy(result->ptr, mf2->ptr, mf2->size);
477                         result->size = mf2->size;
478                 } else if (!xscr2) {
479                         result->ptr = xdl_malloc(mf1->size);
480                         memcpy(result->ptr, mf1->ptr, mf1->size);
481                         result->size = mf1->size;
482                 } else {
483                         status = xdl_do_merge(&xe1, xscr1, name1,
484                                               &xe2, xscr2, name2,
485                                               level, xpp, result);
486                 }
487                 xdl_free_script(xscr1);
488                 xdl_free_script(xscr2);
489         }
490         xdl_free_env(&xe1);
491         xdl_free_env(&xe2);
493         return status;