Win32: fix detection of empty directories in is_dir_empty
[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
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.
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.
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
19 * Davide Libenzi <davidel@xmailserver.org>
23 #include "xinclude.h"
25 typedef struct s_xdmerge {
26 struct s_xdmerge *next;
28 * 0 = conflict,
29 * 1 = no conflict, take first,
30 * 2 = no conflict, take second.
31 * 3 = no conflict, take both.
33 int mode;
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.
40 long i1, i2;
41 long chg1, chg2;
43 * These point at the preimage; of course there is just one
44 * preimage, that is from the shared common ancestor.
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;
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);
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;
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++;
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;
173 dest[size++] = '\n';
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;
192 dest[size++] = '\n';
194 size += xdl_orig_copy(xe1, m->i0, m->chg0, 1,
195 dest ? dest + size : NULL);
198 if (!dest) {
199 size += marker_size + 1;
200 } else {
201 memset(dest + size, '=', marker_size);
202 size += marker_size;
203 dest[size++] = '\n';
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;
219 dest[size++] = '\n';
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;
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.
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;
285 * This probably does not work outside git, since
286 * we have a very simple mmfile structure.
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;
302 if (!xscr) {
303 /* If this happens, the changes are identical. */
304 xdl_free_env(&xe);
305 m->mode = 4;
306 continue;
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;
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;
330 xdl_free_env(&xe);
331 xdl_free_script(x);
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.
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.
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);
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
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) {
425 * "diff3 -m" output does not make sense for anything
426 * more aggressive than XDL_MERGE_EAGER.
428 if (XDL_MERGE_EAGER < level)
429 level = XDL_MERGE_EAGER;
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;
449 xscr1 = xscr1->next;
450 continue;
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;
464 xscr2 = xscr2->next;
465 continue;
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;
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;
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;
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;
523 xscr1 = xscr1->next;
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;
539 xscr2 = xscr2->next;
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;
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;
563 result->size = size;
564 xdl_fill_merge_buffer(xe1, name1, xe2, name2,
565 ancestor_name, favor, changes,
566 result->ptr, style, marker_size);
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;
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;
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;
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);
612 xdl_free_script(xscr1);
613 xdl_free_script(xscr2);
615 xdl_free_env(&xe1);
616 xdl_free_env(&xe2);
618 return status;