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>
25 typedef struct s_xdmerge {
26 struct s_xdmerge *next;
29 * 1 = no conflict, take first,
30 * 2 = no conflict, take second.
31 * 3 = no conflict, take both.
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.
43 * These point at the preimage; of course there is just one
44 * preimage, that is from the shared common ancestor.
50 static int xdl_append_merge(xdmerge_t **merge, int mode,
55 xdmerge_t *m = *merge;
56 if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
59 m->chg0 = i0 + chg0 - m->i0;
60 m->chg1 = i1 + chg1 - m->i1;
61 m->chg2 = i2 + chg2 - m->i2;
63 m = xdl_malloc(sizeof(xdmerge_t));
81 static int xdl_cleanup_merge(xdmerge_t *c)
86 /* were there conflicts? */
87 for (; c; c = next_c) {
96 static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
97 int line_count, long flags)
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);
112 static int xdl_recs_copy_0(int use_orig, xdfenv_t *xe, int i, int count, int add_nl, char *dest)
117 recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
122 for (i = 0; i < count; size += recs[i++]->size)
124 memcpy(dest + size, recs[i]->ptr, recs[i]->size);
126 i = recs[count - 1]->size;
127 if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
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,
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);
157 if (marker_size <= 0)
158 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
160 /* Before conflicting part */
161 size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
162 dest ? dest + size : NULL);
165 size += marker_size + 1 + marker1_size;
167 for (j = 0; j < marker_size; j++)
171 memcpy(dest + size + 1, name1, marker1_size - 1);
172 size += marker1_size;
177 /* Postimage from side #1 */
178 size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
179 dest ? dest + size : NULL);
181 if (style == XDL_MERGE_DIFF3) {
182 /* Shared preimage */
184 size += marker_size + 1 + marker3_size;
186 for (j = 0; j < marker_size; j++)
190 memcpy(dest + size + 1, name3, marker3_size - 1);
191 size += marker3_size;
195 size += xdl_orig_copy(xe1, m->i0, m->chg0, 1,
196 dest ? dest + size : NULL);
200 size += marker_size + 1;
202 for (j = 0; j < marker_size; j++)
207 /* Postimage from side #2 */
208 size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
209 dest ? dest + size : NULL);
211 size += marker_size + 1 + marker2_size;
213 for (j = 0; j < marker_size; j++)
217 memcpy(dest + size + 1, name2, marker2_size - 1);
218 size += marker2_size;
225 static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
226 xdfenv_t *xe2, const char *name2,
227 const char *ancestor_name,
229 xdmerge_t *m, char *dest, int style,
234 for (size = i = 0; m; m = m->next) {
235 if (favor && !m->mode)
239 size = fill_conflict_hunk(xe1, name1, xe2, name2,
241 size, i, style, m, dest,
243 else if (m->mode & 3) {
244 /* Before conflicting part */
245 size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
246 dest ? dest + size : NULL);
247 /* Postimage from side #1 */
249 size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
250 dest ? dest + size : NULL);
251 /* Postimage from side #2 */
253 size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
254 dest ? dest + size : NULL);
259 size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0,
260 dest ? dest + size : NULL);
265 * Sometimes, changes are not quite identical, but differ in only a few
266 * lines. Try hard to show only these few lines as conflicting.
268 static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
269 xpparam_t const *xpp)
271 for (; m; m = m->next) {
274 xdchange_t *xscr, *x;
275 int i1 = m->i1, i2 = m->i2;
277 /* let's handle just the conflicts */
281 /* no sense refining a conflict when one side is empty */
282 if (m->chg1 == 0 || m->chg2 == 0)
286 * This probably does not work outside git, since
287 * we have a very simple mmfile structure.
289 t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
290 t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
291 + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
292 t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
293 t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
294 + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
295 if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
297 if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
298 xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
299 xdl_build_script(&xe, &xscr) < 0) {
304 /* If this happens, the changes are identical. */
310 m->i1 = xscr->i1 + i1;
311 m->chg1 = xscr->chg1;
312 m->i2 = xscr->i2 + i2;
313 m->chg2 = xscr->chg2;
315 xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
326 m->i1 = xscr->i1 + i1;
327 m->chg1 = xscr->chg1;
328 m->i2 = xscr->i2 + i2;
329 m->chg2 = xscr->chg2;
337 static int line_contains_alnum(const char *ptr, long size)
340 if (isalnum(*(ptr++)))
345 static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
347 for (; chg; chg--, i++)
348 if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
349 xe->xdf2.recs[i]->size))
355 * This function merges m and m->next, marking everything between those hunks
356 * as conflicting, too.
358 static void xdl_merge_two_conflicts(xdmerge_t *m)
360 xdmerge_t *next_m = m->next;
361 m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
362 m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
363 m->next = next_m->next;
368 * If there are less than 3 non-conflicting lines between conflicts,
369 * it appears simpler -- because it takes up less (or as many) lines --
370 * if the lines are moved into the conflicts.
372 static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
373 int simplify_if_no_alnum)
380 xdmerge_t *next_m = m->next;
386 begin = m->i1 + m->chg1;
389 if (m->mode != 0 || next_m->mode != 0 ||
391 (!simplify_if_no_alnum ||
392 lines_contain_alnum(xe1, begin, end - begin)))) {
396 xdl_merge_two_conflicts(m);
402 * level == 0: mark all overlapping changes as conflict
403 * level == 1: mark overlapping changes as conflict only if not identical
404 * level == 2: analyze non-identical changes for minimal conflict set
405 * level == 3: analyze non-identical changes for minimal conflict set, but
406 * treat hunks not containing any letter or number as conflicting
408 * returns < 0 on error, == 0 for no conflicts, else number of conflicts
410 static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
411 xdfenv_t *xe2, xdchange_t *xscr2,
412 xmparam_t const *xmp, mmbuffer_t *result)
414 xdmerge_t *changes, *c;
415 xpparam_t const *xpp = &xmp->xpp;
416 const char *const ancestor_name = xmp->ancestor;
417 const char *const name1 = xmp->file1;
418 const char *const name2 = xmp->file2;
419 int i0, i1, i2, chg0, chg1, chg2;
420 int level = xmp->level;
421 int style = xmp->style;
422 int favor = xmp->favor;
424 if (style == XDL_MERGE_DIFF3) {
426 * "diff3 -m" output does not make sense for anything
427 * more aggressive than XDL_MERGE_EAGER.
429 if (XDL_MERGE_EAGER < level)
430 level = XDL_MERGE_EAGER;
435 while (xscr1 && xscr2) {
438 if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
441 i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
445 if (xdl_append_merge(&c, 1,
446 i0, chg0, i1, chg1, i2, chg2)) {
447 xdl_cleanup_merge(changes);
453 if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
455 i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
460 if (xdl_append_merge(&c, 2,
461 i0, chg0, i1, chg1, i2, chg2)) {
462 xdl_cleanup_merge(changes);
468 if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
469 xscr1->chg1 != xscr2->chg1 ||
470 xscr1->chg2 != xscr2->chg2 ||
471 xdl_merge_cmp_lines(xe1, xscr1->i2,
473 xscr1->chg2, xpp->flags)) {
475 int off = xscr1->i1 - xscr2->i1;
476 int ffo = off + xscr1->chg1 - xscr2->chg1;
487 chg0 = xscr1->i1 + xscr1->chg1 - i0;
488 chg1 = xscr1->i2 + xscr1->chg2 - i1;
489 chg2 = xscr2->i2 + xscr2->chg2 - i2;
495 if (xdl_append_merge(&c, 0,
496 i0, chg0, i1, chg1, i2, chg2)) {
497 xdl_cleanup_merge(changes);
502 i1 = xscr1->i1 + xscr1->chg1;
503 i2 = xscr2->i1 + xscr2->chg1;
515 i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
519 if (xdl_append_merge(&c, 1,
520 i0, chg0, i1, chg1, i2, chg2)) {
521 xdl_cleanup_merge(changes);
530 i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
535 if (xdl_append_merge(&c, 2,
536 i0, chg0, i1, chg1, i2, chg2)) {
537 xdl_cleanup_merge(changes);
544 /* refine conflicts */
545 if (XDL_MERGE_ZEALOUS <= level &&
546 (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
547 xdl_simplify_non_conflicts(xe1, changes,
548 XDL_MERGE_ZEALOUS < level) < 0)) {
549 xdl_cleanup_merge(changes);
554 int marker_size = xmp->marker_size;
555 int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
557 favor, changes, NULL, style,
559 result->ptr = xdl_malloc(size);
561 xdl_cleanup_merge(changes);
565 xdl_fill_merge_buffer(xe1, name1, xe2, name2,
566 ancestor_name, favor, changes,
567 result->ptr, style, marker_size);
569 return xdl_cleanup_merge(changes);
572 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
573 xmparam_t const *xmp, mmbuffer_t *result)
575 xdchange_t *xscr1, *xscr2;
578 xpparam_t const *xpp = &xmp->xpp;
583 if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
584 xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
587 if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
588 xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
589 xdl_build_script(&xe1, &xscr1) < 0) {
593 if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
594 xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
595 xdl_build_script(&xe2, &xscr2) < 0) {
601 result->ptr = xdl_malloc(mf2->size);
602 memcpy(result->ptr, mf2->ptr, mf2->size);
603 result->size = mf2->size;
605 result->ptr = xdl_malloc(mf1->size);
606 memcpy(result->ptr, mf1->ptr, mf1->size);
607 result->size = mf1->size;
609 status = xdl_do_merge(&xe1, xscr1,
613 xdl_free_script(xscr1);
614 xdl_free_script(xscr2);