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 */
22#include "xinclude.h"
24typedef 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;
48static 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}
79static int xdl_cleanup_merge(xdmerge_t *c)
81{
82 int count = 0;
83 xdmerge_t *next_c;
84 /* 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}
94static 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;
101 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}
110static 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;
115 recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
117 if (count < 1)
119 return 0;
120 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}
134static 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}
139static 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}
144static 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;
154 /* Before conflicting part */
156 size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
157 dest ? dest + size : NULL);
158 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 }
171 /* Postimage from side #1 */
173 size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
174 dest ? dest + size : NULL);
175 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 }
188 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 }
196 /* 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}
214static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
216 xdfenv_t *xe2, const char *name2,
217 xdmerge_t *m, char *dest, int style)
218{
219 int size, i;
220 for (size = i = 0; m; m = m->next) {
222 if (m->mode == 0)
223 size = fill_conflict_hunk(xe1, name1, xe2, name2,
224 size, i, style, m, dest);
225 else if (m->mode == 1)
226 size += xdl_recs_copy(xe1, i, m->i1 + m->chg1 - i, 0,
227 dest ? dest + size : NULL);
228 else if (m->mode == 2)
229 size += xdl_recs_copy(xe2, m->i2 - m->i1 + i,
230 m->i1 + m->chg2 - i, 0,
231 dest ? dest + size : NULL);
232 else
233 continue;
234 i = m->i1 + m->chg1;
235 }
236 size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0,
237 dest ? dest + size : NULL);
238 return size;
239}
240/*
242 * Sometimes, changes are not quite identical, but differ in only a few
243 * lines. Try hard to show only these few lines as conflicting.
244 */
245static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
246 xpparam_t const *xpp)
247{
248 for (; m; m = m->next) {
249 mmfile_t t1, t2;
250 xdfenv_t xe;
251 xdchange_t *xscr, *x;
252 int i1 = m->i1, i2 = m->i2;
253 /* let's handle just the conflicts */
255 if (m->mode)
256 continue;
257 /* no sense refining a conflict when one side is empty */
259 if (m->chg1 == 0 || m->chg2 == 0)
260 continue;
261 /*
263 * This probably does not work outside git, since
264 * we have a very simple mmfile structure.
265 */
266 t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
267 t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
268 + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
269 t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
270 t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
271 + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
272 if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
273 return -1;
274 if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
275 xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
276 xdl_build_script(&xe, &xscr) < 0) {
277 xdl_free_env(&xe);
278 return -1;
279 }
280 if (!xscr) {
281 /* If this happens, the changes are identical. */
282 xdl_free_env(&xe);
283 m->mode = 4;
284 continue;
285 }
286 x = xscr;
287 m->i1 = xscr->i1 + i1;
288 m->chg1 = xscr->chg1;
289 m->i2 = xscr->i2 + i2;
290 m->chg2 = xscr->chg2;
291 while (xscr->next) {
292 xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
293 if (!m2) {
294 xdl_free_env(&xe);
295 xdl_free_script(x);
296 return -1;
297 }
298 xscr = xscr->next;
299 m2->next = m->next;
300 m->next = m2;
301 m = m2;
302 m->mode = 0;
303 m->i1 = xscr->i1 + i1;
304 m->chg1 = xscr->chg1;
305 m->i2 = xscr->i2 + i2;
306 m->chg2 = xscr->chg2;
307 }
308 xdl_free_env(&xe);
309 xdl_free_script(x);
310 }
311 return 0;
312}
313static int line_contains_alnum(const char *ptr, long size)
315{
316 while (size--)
317 if (isalnum(*(ptr++)))
318 return 1;
319 return 0;
320}
321static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
323{
324 for (; chg; chg--, i++)
325 if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
326 xe->xdf2.recs[i]->size))
327 return 1;
328 return 0;
329}
330/*
332 * This function merges m and m->next, marking everything between those hunks
333 * as conflicting, too.
334 */
335static void xdl_merge_two_conflicts(xdmerge_t *m)
336{
337 xdmerge_t *next_m = m->next;
338 m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
339 m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
340 m->next = next_m->next;
341 free(next_m);
342}
343/*
345 * If there are less than 3 non-conflicting lines between conflicts,
346 * it appears simpler -- because it takes up less (or as many) lines --
347 * if the lines are moved into the conflicts.
348 */
349static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
350 int simplify_if_no_alnum)
351{
352 int result = 0;
353 if (!m)
355 return result;
356 for (;;) {
357 xdmerge_t *next_m = m->next;
358 int begin, end;
359 if (!next_m)
361 return result;
362 begin = m->i1 + m->chg1;
364 end = next_m->i1;
365 if (m->mode != 0 || next_m->mode != 0 ||
367 (end - begin > 3 &&
368 (!simplify_if_no_alnum ||
369 lines_contain_alnum(xe1, begin, end - begin)))) {
370 m = next_m;
371 } else {
372 result++;
373 xdl_merge_two_conflicts(m);
374 }
375 }
376}
377/*
379 * level == 0: mark all overlapping changes as conflict
380 * level == 1: mark overlapping changes as conflict only if not identical
381 * level == 2: analyze non-identical changes for minimal conflict set
382 * level == 3: analyze non-identical changes for minimal conflict set, but
383 * treat hunks not containing any letter or number as conflicting
384 *
385 * returns < 0 on error, == 0 for no conflicts, else number of conflicts
386 */
387static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1, const char *name1,
388 xdfenv_t *xe2, xdchange_t *xscr2, const char *name2,
389 int flags, xpparam_t const *xpp, mmbuffer_t *result) {
390 xdmerge_t *changes, *c;
391 int i0, i1, i2, chg0, chg1, chg2;
392 int level = flags & XDL_MERGE_LEVEL_MASK;
393 int style = flags & XDL_MERGE_STYLE_MASK;
394 if (style == XDL_MERGE_DIFF3) {
396 /*
397 * "diff3 -m" output does not make sense for anything
398 * more aggressive than XDL_MERGE_EAGER.
399 */
400 if (XDL_MERGE_EAGER < level)
401 level = XDL_MERGE_EAGER;
402 }
403 c = changes = NULL;
405 while (xscr1 && xscr2) {
407 if (!changes)
408 changes = c;
409 if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
410 i0 = xscr1->i1;
411 i1 = xscr1->i2;
412 i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
413 chg0 = xscr1->chg1;
414 chg1 = xscr1->chg2;
415 chg2 = xscr1->chg1;
416 if (xdl_append_merge(&c, 1,
417 i0, chg0, i1, chg1, i2, chg2)) {
418 xdl_cleanup_merge(changes);
419 return -1;
420 }
421 xscr1 = xscr1->next;
422 continue;
423 }
424 if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
425 i0 = xscr2->i1;
426 i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
427 i2 = xscr2->i2;
428 chg0 = xscr2->chg1;
429 chg1 = xscr2->chg1;
430 chg2 = xscr2->chg2;
431 if (xdl_append_merge(&c, 2,
432 i0, chg0, i1, chg1, i2, chg2)) {
433 xdl_cleanup_merge(changes);
434 return -1;
435 }
436 xscr2 = xscr2->next;
437 continue;
438 }
439 if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
440 xscr1->chg1 != xscr2->chg1 ||
441 xscr1->chg2 != xscr2->chg2 ||
442 xdl_merge_cmp_lines(xe1, xscr1->i2,
443 xe2, xscr2->i2,
444 xscr1->chg2, xpp->flags)) {
445 /* conflict */
446 int off = xscr1->i1 - xscr2->i1;
447 int ffo = off + xscr1->chg1 - xscr2->chg1;
448 i0 = xscr1->i1;
450 i1 = xscr1->i2;
451 i2 = xscr2->i2;
452 if (off > 0) {
453 i0 -= off;
454 i1 -= off;
455 }
456 else
457 i2 += off;
458 chg0 = xscr1->i1 + xscr1->chg1 - i0;
459 chg1 = xscr1->i2 + xscr1->chg2 - i1;
460 chg2 = xscr2->i2 + xscr2->chg2 - i2;
461 if (ffo < 0) {
462 chg0 -= ffo;
463 chg1 -= ffo;
464 } else
465 chg2 += ffo;
466 if (xdl_append_merge(&c, 0,
467 i0, chg0, i1, chg1, i2, chg2)) {
468 xdl_cleanup_merge(changes);
469 return -1;
470 }
471 }
472 i1 = xscr1->i1 + xscr1->chg1;
474 i2 = xscr2->i1 + xscr2->chg1;
475 if (i1 >= i2)
477 xscr2 = xscr2->next;
478 if (i2 >= i1)
479 xscr1 = xscr1->next;
480 }
481 while (xscr1) {
482 if (!changes)
483 changes = c;
484 i0 = xscr1->i1;
485 i1 = xscr1->i2;
486 i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
487 chg0 = xscr1->chg1;
488 chg1 = xscr1->chg2;
489 chg2 = xscr1->chg1;
490 if (xdl_append_merge(&c, 1,
491 i0, chg0, i1, chg1, i2, chg2)) {
492 xdl_cleanup_merge(changes);
493 return -1;
494 }
495 xscr1 = xscr1->next;
496 }
497 while (xscr2) {
498 if (!changes)
499 changes = c;
500 i0 = xscr2->i1;
501 i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
502 i2 = xscr2->i2;
503 chg0 = xscr2->chg1;
504 chg1 = xscr2->chg1;
505 chg2 = xscr2->chg2;
506 if (xdl_append_merge(&c, 2,
507 i0, chg0, i1, chg1, i2, chg2)) {
508 xdl_cleanup_merge(changes);
509 return -1;
510 }
511 xscr2 = xscr2->next;
512 }
513 if (!changes)
514 changes = c;
515 /* refine conflicts */
516 if (XDL_MERGE_ZEALOUS <= level &&
517 (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
518 xdl_simplify_non_conflicts(xe1, changes,
519 XDL_MERGE_ZEALOUS < level) < 0)) {
520 xdl_cleanup_merge(changes);
521 return -1;
522 }
523 /* output */
524 if (result) {
525 int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
526 changes, NULL, style);
527 result->ptr = xdl_malloc(size);
528 if (!result->ptr) {
529 xdl_cleanup_merge(changes);
530 return -1;
531 }
532 result->size = size;
533 xdl_fill_merge_buffer(xe1, name1, xe2, name2, changes,
534 result->ptr, style);
535 }
536 return xdl_cleanup_merge(changes);
537}
538int xdl_merge(mmfile_t *orig, mmfile_t *mf1, const char *name1,
540 mmfile_t *mf2, const char *name2,
541 xpparam_t const *xpp, int flags, mmbuffer_t *result) {
542 xdchange_t *xscr1, *xscr2;
543 xdfenv_t xe1, xe2;
544 int status;
545 result->ptr = NULL;
547 result->size = 0;
548 if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
550 xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
551 return -1;
552 }
553 if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
554 xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
555 xdl_build_script(&xe1, &xscr1) < 0) {
556 xdl_free_env(&xe1);
557 return -1;
558 }
559 if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
560 xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
561 xdl_build_script(&xe2, &xscr2) < 0) {
562 xdl_free_env(&xe2);
563 return -1;
564 }
565 status = 0;
566 if (xscr1 || xscr2) {
567 if (!xscr1) {
568 result->ptr = xdl_malloc(mf2->size);
569 memcpy(result->ptr, mf2->ptr, mf2->size);
570 result->size = mf2->size;
571 } else if (!xscr2) {
572 result->ptr = xdl_malloc(mf1->size);
573 memcpy(result->ptr, mf1->ptr, mf1->size);
574 result->size = mf1->size;
575 } else {
576 status = xdl_do_merge(&xe1, xscr1, name1,
577 &xe2, xscr2, name2,
578 flags, xpp, result);
579 }
580 xdl_free_script(xscr1);
581 xdl_free_script(xscr2);
582 }
583 xdl_free_env(&xe1);
584 xdl_free_env(&xe2);
585 return status;
587}