b2ddc75376f530a07cb951bc8314c4a635517af5
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 /*
34 * These point at the respective postimages. E.g. <i1,chg1> is
35 * how side #1 wants to change the common ancestor; if there is no
36 * overlap, lines before i1 in the postimage of side #1 appear
37 * in the merge result as a region touched by neither side.
38 */
39 long i1, i2;
40 long chg1, chg2;
41 /*
42 * These point at the preimage; of course there is just one
43 * preimage, that is from the shared common ancestor.
44 */
45 long i0;
46 long chg0;
47 } xdmerge_t;
49 static int xdl_append_merge(xdmerge_t **merge, int mode,
50 long i0, long chg0,
51 long i1, long chg1,
52 long i2, long chg2)
53 {
54 xdmerge_t *m = *merge;
55 if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
56 if (mode != m->mode)
57 m->mode = 0;
58 m->chg0 = i0 + chg0 - m->i0;
59 m->chg1 = i1 + chg1 - m->i1;
60 m->chg2 = i2 + chg2 - m->i2;
61 } else {
62 m = xdl_malloc(sizeof(xdmerge_t));
63 if (!m)
64 return -1;
65 m->next = NULL;
66 m->mode = mode;
67 m->i0 = i0;
68 m->chg0 = chg0;
69 m->i1 = i1;
70 m->chg1 = chg1;
71 m->i2 = i2;
72 m->chg2 = chg2;
73 if (*merge)
74 (*merge)->next = m;
75 *merge = m;
76 }
77 return 0;
78 }
80 static int xdl_cleanup_merge(xdmerge_t *c)
81 {
82 int count = 0;
83 xdmerge_t *next_c;
85 /* were there conflicts? */
86 for (; c; c = next_c) {
87 if (c->mode == 0)
88 count++;
89 next_c = c->next;
90 free(c);
91 }
92 return count;
93 }
95 static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
96 int line_count, long flags)
97 {
98 int i;
99 xrecord_t **rec1 = xe1->xdf2.recs + i1;
100 xrecord_t **rec2 = xe2->xdf2.recs + i2;
102 for (i = 0; i < line_count; i++) {
103 int result = xdl_recmatch(rec1[i]->ptr, rec1[i]->size,
104 rec2[i]->ptr, rec2[i]->size, flags);
105 if (!result)
106 return -1;
107 }
108 return 0;
109 }
111 static int xdl_recs_copy_0(int use_orig, xdfenv_t *xe, int i, int count, int add_nl, char *dest)
112 {
113 xrecord_t **recs;
114 int size = 0;
116 recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
118 if (count < 1)
119 return 0;
121 for (i = 0; i < count; size += recs[i++]->size)
122 if (dest)
123 memcpy(dest + size, recs[i]->ptr, recs[i]->size);
124 if (add_nl) {
125 i = recs[count - 1]->size;
126 if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
127 if (dest)
128 dest[size] = '\n';
129 size++;
130 }
131 }
132 return size;
133 }
135 static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
136 {
137 return xdl_recs_copy_0(0, xe, i, count, add_nl, dest);
138 }
140 static int xdl_orig_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
141 {
142 return xdl_recs_copy_0(1, xe, i, count, add_nl, dest);
143 }
145 static int fill_conflict_hunk(xdfenv_t *xe1, const char *name1,
146 xdfenv_t *xe2, const char *name2,
147 int size, int i, int style,
148 xdmerge_t *m, char *dest)
149 {
150 const int marker_size = 7;
151 int marker1_size = (name1 ? strlen(name1) + 1 : 0);
152 int marker2_size = (name2 ? strlen(name2) + 1 : 0);
153 int j;
155 /* Before conflicting part */
156 size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
157 dest ? dest + size : NULL);
159 if (!dest) {
160 size += marker_size + 1 + marker1_size;
161 } else {
162 for (j = 0; j < marker_size; j++)
163 dest[size++] = '<';
164 if (marker1_size) {
165 dest[size] = ' ';
166 memcpy(dest + size + 1, name1, marker1_size - 1);
167 size += marker1_size;
168 }
169 dest[size++] = '\n';
170 }
172 /* Postimage from side #1 */
173 size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
174 dest ? dest + size : NULL);
176 if (style == XDL_MERGE_DIFF3) {
177 /* Shared preimage */
178 if (!dest) {
179 size += marker_size + 1;
180 } else {
181 for (j = 0; j < marker_size; j++)
182 dest[size++] = '|';
183 dest[size++] = '\n';
184 }
185 size += xdl_orig_copy(xe1, m->i0, m->chg0, 1,
186 dest ? dest + size : NULL);
187 }
189 if (!dest) {
190 size += marker_size + 1;
191 } else {
192 for (j = 0; j < marker_size; j++)
193 dest[size++] = '=';
194 dest[size++] = '\n';
195 }
197 /* Postimage from side #2 */
198 size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
199 dest ? dest + size : NULL);
200 if (!dest) {
201 size += marker_size + 1 + marker2_size;
202 } else {
203 for (j = 0; j < marker_size; j++)
204 dest[size++] = '>';
205 if (marker2_size) {
206 dest[size] = ' ';
207 memcpy(dest + size + 1, name2, marker2_size - 1);
208 size += marker2_size;
209 }
210 dest[size++] = '\n';
211 }
212 return size;
213 }
215 static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
216 xdfenv_t *xe2, const char *name2,
217 int favor,
218 xdmerge_t *m, char *dest, int style)
219 {
220 int size, i;
222 for (size = i = 0; m; m = m->next) {
223 if (favor && !m->mode)
224 m->mode = favor;
226 if (m->mode == 0)
227 size = fill_conflict_hunk(xe1, name1, xe2, name2,
228 size, i, style, m, dest);
229 else if (m->mode == 1)
230 size += xdl_recs_copy(xe1, i, m->i1 + m->chg1 - i, 0,
231 dest ? dest + size : NULL);
232 else if (m->mode == 2)
233 size += xdl_recs_copy(xe2, m->i2 - m->i1 + i,
234 m->i1 + m->chg2 - i, 0,
235 dest ? dest + size : NULL);
236 else
237 continue;
238 i = m->i1 + m->chg1;
239 }
240 size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0,
241 dest ? dest + size : NULL);
242 return size;
243 }
245 /*
246 * Sometimes, changes are not quite identical, but differ in only a few
247 * lines. Try hard to show only these few lines as conflicting.
248 */
249 static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
250 xpparam_t const *xpp)
251 {
252 for (; m; m = m->next) {
253 mmfile_t t1, t2;
254 xdfenv_t xe;
255 xdchange_t *xscr, *x;
256 int i1 = m->i1, i2 = m->i2;
258 /* let's handle just the conflicts */
259 if (m->mode)
260 continue;
262 /* no sense refining a conflict when one side is empty */
263 if (m->chg1 == 0 || m->chg2 == 0)
264 continue;
266 /*
267 * This probably does not work outside git, since
268 * we have a very simple mmfile structure.
269 */
270 t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
271 t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
272 + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
273 t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
274 t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
275 + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
276 if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
277 return -1;
278 if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
279 xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
280 xdl_build_script(&xe, &xscr) < 0) {
281 xdl_free_env(&xe);
282 return -1;
283 }
284 if (!xscr) {
285 /* If this happens, the changes are identical. */
286 xdl_free_env(&xe);
287 m->mode = 4;
288 continue;
289 }
290 x = xscr;
291 m->i1 = xscr->i1 + i1;
292 m->chg1 = xscr->chg1;
293 m->i2 = xscr->i2 + i2;
294 m->chg2 = xscr->chg2;
295 while (xscr->next) {
296 xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
297 if (!m2) {
298 xdl_free_env(&xe);
299 xdl_free_script(x);
300 return -1;
301 }
302 xscr = xscr->next;
303 m2->next = m->next;
304 m->next = m2;
305 m = m2;
306 m->mode = 0;
307 m->i1 = xscr->i1 + i1;
308 m->chg1 = xscr->chg1;
309 m->i2 = xscr->i2 + i2;
310 m->chg2 = xscr->chg2;
311 }
312 xdl_free_env(&xe);
313 xdl_free_script(x);
314 }
315 return 0;
316 }
318 static int line_contains_alnum(const char *ptr, long size)
319 {
320 while (size--)
321 if (isalnum(*(ptr++)))
322 return 1;
323 return 0;
324 }
326 static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
327 {
328 for (; chg; chg--, i++)
329 if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
330 xe->xdf2.recs[i]->size))
331 return 1;
332 return 0;
333 }
335 /*
336 * This function merges m and m->next, marking everything between those hunks
337 * as conflicting, too.
338 */
339 static void xdl_merge_two_conflicts(xdmerge_t *m)
340 {
341 xdmerge_t *next_m = m->next;
342 m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
343 m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
344 m->next = next_m->next;
345 free(next_m);
346 }
348 /*
349 * If there are less than 3 non-conflicting lines between conflicts,
350 * it appears simpler -- because it takes up less (or as many) lines --
351 * if the lines are moved into the conflicts.
352 */
353 static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
354 int simplify_if_no_alnum)
355 {
356 int result = 0;
358 if (!m)
359 return result;
360 for (;;) {
361 xdmerge_t *next_m = m->next;
362 int begin, end;
364 if (!next_m)
365 return result;
367 begin = m->i1 + m->chg1;
368 end = next_m->i1;
370 if (m->mode != 0 || next_m->mode != 0 ||
371 (end - begin > 3 &&
372 (!simplify_if_no_alnum ||
373 lines_contain_alnum(xe1, begin, end - begin)))) {
374 m = next_m;
375 } else {
376 result++;
377 xdl_merge_two_conflicts(m);
378 }
379 }
380 }
382 /*
383 * level == 0: mark all overlapping changes as conflict
384 * level == 1: mark overlapping changes as conflict only if not identical
385 * level == 2: analyze non-identical changes for minimal conflict set
386 * level == 3: analyze non-identical changes for minimal conflict set, but
387 * treat hunks not containing any letter or number as conflicting
388 *
389 * returns < 0 on error, == 0 for no conflicts, else number of conflicts
390 */
391 static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1, const char *name1,
392 xdfenv_t *xe2, xdchange_t *xscr2, const char *name2,
393 int flags, xpparam_t const *xpp, mmbuffer_t *result) {
394 xdmerge_t *changes, *c;
395 int i0, i1, i2, chg0, chg1, chg2;
396 int level = flags & XDL_MERGE_LEVEL_MASK;
397 int style = flags & XDL_MERGE_STYLE_MASK;
398 int favor = XDL_MERGE_FAVOR(flags);
400 if (style == XDL_MERGE_DIFF3) {
401 /*
402 * "diff3 -m" output does not make sense for anything
403 * more aggressive than XDL_MERGE_EAGER.
404 */
405 if (XDL_MERGE_EAGER < level)
406 level = XDL_MERGE_EAGER;
407 }
409 c = changes = NULL;
411 while (xscr1 && xscr2) {
412 if (!changes)
413 changes = c;
414 if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
415 i0 = xscr1->i1;
416 i1 = xscr1->i2;
417 i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
418 chg0 = xscr1->chg1;
419 chg1 = xscr1->chg2;
420 chg2 = xscr1->chg1;
421 if (xdl_append_merge(&c, 1,
422 i0, chg0, i1, chg1, i2, chg2)) {
423 xdl_cleanup_merge(changes);
424 return -1;
425 }
426 xscr1 = xscr1->next;
427 continue;
428 }
429 if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
430 i0 = xscr2->i1;
431 i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
432 i2 = xscr2->i2;
433 chg0 = xscr2->chg1;
434 chg1 = xscr2->chg1;
435 chg2 = xscr2->chg2;
436 if (xdl_append_merge(&c, 2,
437 i0, chg0, i1, chg1, i2, chg2)) {
438 xdl_cleanup_merge(changes);
439 return -1;
440 }
441 xscr2 = xscr2->next;
442 continue;
443 }
444 if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
445 xscr1->chg1 != xscr2->chg1 ||
446 xscr1->chg2 != xscr2->chg2 ||
447 xdl_merge_cmp_lines(xe1, xscr1->i2,
448 xe2, xscr2->i2,
449 xscr1->chg2, xpp->flags)) {
450 /* conflict */
451 int off = xscr1->i1 - xscr2->i1;
452 int ffo = off + xscr1->chg1 - xscr2->chg1;
454 i0 = xscr1->i1;
455 i1 = xscr1->i2;
456 i2 = xscr2->i2;
457 if (off > 0) {
458 i0 -= off;
459 i1 -= off;
460 }
461 else
462 i2 += off;
463 chg0 = xscr1->i1 + xscr1->chg1 - i0;
464 chg1 = xscr1->i2 + xscr1->chg2 - i1;
465 chg2 = xscr2->i2 + xscr2->chg2 - i2;
466 if (ffo < 0) {
467 chg0 -= ffo;
468 chg1 -= ffo;
469 } else
470 chg2 += ffo;
471 if (xdl_append_merge(&c, 0,
472 i0, chg0, i1, chg1, i2, chg2)) {
473 xdl_cleanup_merge(changes);
474 return -1;
475 }
476 }
478 i1 = xscr1->i1 + xscr1->chg1;
479 i2 = xscr2->i1 + xscr2->chg1;
481 if (i1 >= i2)
482 xscr2 = xscr2->next;
483 if (i2 >= i1)
484 xscr1 = xscr1->next;
485 }
486 while (xscr1) {
487 if (!changes)
488 changes = c;
489 i0 = xscr1->i1;
490 i1 = xscr1->i2;
491 i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
492 chg0 = xscr1->chg1;
493 chg1 = xscr1->chg2;
494 chg2 = xscr1->chg1;
495 if (xdl_append_merge(&c, 1,
496 i0, chg0, i1, chg1, i2, chg2)) {
497 xdl_cleanup_merge(changes);
498 return -1;
499 }
500 xscr1 = xscr1->next;
501 }
502 while (xscr2) {
503 if (!changes)
504 changes = c;
505 i0 = xscr2->i1;
506 i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
507 i2 = xscr2->i2;
508 chg0 = xscr2->chg1;
509 chg1 = xscr2->chg1;
510 chg2 = xscr2->chg2;
511 if (xdl_append_merge(&c, 2,
512 i0, chg0, i1, chg1, i2, chg2)) {
513 xdl_cleanup_merge(changes);
514 return -1;
515 }
516 xscr2 = xscr2->next;
517 }
518 if (!changes)
519 changes = c;
520 /* refine conflicts */
521 if (XDL_MERGE_ZEALOUS <= level &&
522 (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
523 xdl_simplify_non_conflicts(xe1, changes,
524 XDL_MERGE_ZEALOUS < level) < 0)) {
525 xdl_cleanup_merge(changes);
526 return -1;
527 }
528 /* output */
529 if (result) {
530 int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
531 favor, changes, NULL, style);
532 result->ptr = xdl_malloc(size);
533 if (!result->ptr) {
534 xdl_cleanup_merge(changes);
535 return -1;
536 }
537 result->size = size;
538 xdl_fill_merge_buffer(xe1, name1, xe2, name2, favor, changes,
539 result->ptr, style);
540 }
541 return xdl_cleanup_merge(changes);
542 }
544 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, const char *name1,
545 mmfile_t *mf2, const char *name2,
546 xpparam_t const *xpp, int flags, mmbuffer_t *result) {
547 xdchange_t *xscr1, *xscr2;
548 xdfenv_t xe1, xe2;
549 int status;
551 result->ptr = NULL;
552 result->size = 0;
554 if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
555 xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
556 return -1;
557 }
558 if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
559 xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
560 xdl_build_script(&xe1, &xscr1) < 0) {
561 xdl_free_env(&xe1);
562 return -1;
563 }
564 if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
565 xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
566 xdl_build_script(&xe2, &xscr2) < 0) {
567 xdl_free_env(&xe2);
568 return -1;
569 }
570 status = 0;
571 if (!xscr1) {
572 result->ptr = xdl_malloc(mf2->size);
573 memcpy(result->ptr, mf2->ptr, mf2->size);
574 result->size = mf2->size;
575 } else if (!xscr2) {
576 result->ptr = xdl_malloc(mf1->size);
577 memcpy(result->ptr, mf1->ptr, mf1->size);
578 result->size = mf1->size;
579 } else {
580 status = xdl_do_merge(&xe1, xscr1, name1,
581 &xe2, xscr2, name2,
582 flags, xpp, result);
583 }
584 xdl_free_script(xscr1);
585 xdl_free_script(xscr2);
587 xdl_free_env(&xe1);
588 xdl_free_env(&xe2);
590 return status;
591 }