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 long i1, i2;
34 long chg1, chg2;
35} xdmerge_t;
36static int xdl_append_merge(xdmerge_t **merge, int mode,
38 long i1, long chg1, long i2, long chg2)
39{
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;
61}
62static int xdl_cleanup_merge(xdmerge_t *c)
64{
65 int count = 0;
66 xdmerge_t *next_c;
67 /* 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;
76}
77static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
79 int line_count, long flags)
80{
81 int i;
82 xrecord_t **rec1 = xe1->xdf2.recs + i1;
83 xrecord_t **rec2 = xe2->xdf2.recs + i2;
84 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;
92}
93static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
95{
96 xrecord_t **recs = xe->xdf2.recs + i;
97 int size = 0;
98 if (count < 1)
100 return 0;
101 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;
114}
115static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
117 xdfenv_t *xe2, const char *name2, xdmerge_t *m, char *dest)
118{
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;
125 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;
176}
177/*
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 */
182static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
183 xpparam_t const *xpp)
184{
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;
190 /* let's handle just the conflicts */
192 if (m->mode)
193 continue;
194 /* no sense refining a conflict when one side is empty */
196 if (m->chg1 == 0 || m->chg2 == 0)
197 continue;
198 /*
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;
249}
250static int line_contains_alnum(const char *ptr, long size)
252{
253 while (size--)
254 if (isalnum(*(ptr++)))
255 return 1;
256 return 0;
257}
258static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
260{
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;
266}
267/*
269 * This function merges m and m->next, marking everything between those hunks
270 * as conflicting, too.
271 */
272static void xdl_merge_two_conflicts(xdmerge_t *m)
273{
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);
279}
280/*
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 */
286static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
287 int simplify_if_no_alnum)
288{
289 int result = 0;
290 if (!m)
292 return result;
293 for (;;) {
294 xdmerge_t *next_m = m->next;
295 int begin, end;
296 if (!next_m)
298 return result;
299 begin = m->i1 + m->chg1;
301 end = next_m->i1;
302 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 }
313}
314/*
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
321 *
322 * returns < 0 on error, == 0 for no conflicts, else number of conflicts
323 */
324static 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;
329 c = changes = NULL;
331 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;
368 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 }
386 i1 = xscr1->i1 + xscr1->chg1;
388 i2 = xscr2->i1 + xscr2->chg1;
389 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);
444}
445int 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;
452 result->ptr = NULL;
454 result->size = 0;
455 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);
492 return status;
494}