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857b933e JS |
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 | ||
23 | #include "xinclude.h" | |
24 | ||
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 | long i1, i2; | |
34 | long chg1, chg2; | |
35 | } xdmerge_t; | |
36 | ||
37 | static int xdl_append_merge(xdmerge_t **merge, int mode, | |
38 | long i1, long chg1, long i2, long chg2) | |
39 | { | |
40 | xdmerge_t *m = *merge; | |
98e6da8a JS |
41 | if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) { |
42 | if (mode != m->mode) | |
43 | m->mode = 0; | |
857b933e JS |
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 | } | |
62 | ||
63 | static int xdl_cleanup_merge(xdmerge_t *c) | |
64 | { | |
65 | int count = 0; | |
66 | xdmerge_t *next_c; | |
67 | ||
68 | /* 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 | } | |
77 | ||
78 | static 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 | ||
85 | 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 | } | |
93 | ||
94 | static 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 | ||
99 | if (count < 1) | |
100 | return 0; | |
101 | ||
102 | 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 | } | |
115 | ||
116 | static 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 | ||
126 | 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); | |
22b6abcd JS |
169 | else |
170 | continue; | |
857b933e JS |
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 | ||
178 | /* | |
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 | */ | |
182 | static 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 | ||
191 | /* let's handle just the conflicts */ | |
192 | if (m->mode) | |
193 | continue; | |
194 | ||
5d6b151f JS |
195 | /* no sense refining a conflict when one side is empty */ |
196 | if (m->chg1 == 0 || m->chg2 == 0) | |
197 | continue; | |
198 | ||
857b933e JS |
199 | /* |
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; | |
875b8ce4 JS |
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; | |
857b933e JS |
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) { | |
22b6abcd | 218 | /* If this happens, the changes are identical. */ |
857b933e | 219 | xdl_free_env(&xe); |
22b6abcd JS |
220 | m->mode = 4; |
221 | continue; | |
857b933e JS |
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 | } | |
250 | ||
f407f14d JS |
251 | /* |
252 | * This function merges m and m->next, marking everything between those hunks | |
253 | * as conflicting, too. | |
254 | */ | |
255 | static void xdl_merge_two_conflicts(xdmerge_t *m) | |
256 | { | |
257 | xdmerge_t *next_m = m->next; | |
258 | m->chg1 = next_m->i1 + next_m->chg1 - m->i1; | |
259 | m->chg2 = next_m->i2 + next_m->chg2 - m->i2; | |
260 | m->next = next_m->next; | |
261 | free(next_m); | |
262 | } | |
263 | ||
264 | /* | |
265 | * If there are less than 3 non-conflicting lines between conflicts, | |
266 | * it appears simpler -- because it takes up less (or as many) lines -- | |
267 | * if the lines are moved into the conflicts. | |
268 | */ | |
269 | static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m) | |
270 | { | |
271 | int result = 0; | |
272 | ||
273 | if (!m) | |
274 | return result; | |
275 | for (;;) { | |
276 | xdmerge_t *next_m = m->next; | |
277 | int begin, end; | |
278 | ||
279 | if (!next_m) | |
280 | return result; | |
281 | ||
282 | begin = m->i1 + m->chg1; | |
283 | end = next_m->i1; | |
284 | ||
285 | if (m->mode != 0 || next_m->mode != 0 || end - begin > 3) | |
286 | m = next_m; | |
287 | else { | |
288 | result++; | |
289 | xdl_merge_two_conflicts(m); | |
290 | } | |
291 | } | |
292 | } | |
293 | ||
857b933e JS |
294 | /* |
295 | * level == 0: mark all overlapping changes as conflict | |
296 | * level == 1: mark overlapping changes as conflict only if not identical | |
297 | * level == 2: analyze non-identical changes for minimal conflict set | |
298 | * | |
299 | * returns < 0 on error, == 0 for no conflicts, else number of conflicts | |
300 | */ | |
301 | static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1, const char *name1, | |
302 | xdfenv_t *xe2, xdchange_t *xscr2, const char *name2, | |
303 | int level, xpparam_t const *xpp, mmbuffer_t *result) { | |
304 | xdmerge_t *changes, *c; | |
305 | int i1, i2, chg1, chg2; | |
306 | ||
307 | c = changes = NULL; | |
308 | ||
309 | while (xscr1 && xscr2) { | |
310 | if (!changes) | |
311 | changes = c; | |
312 | if (xscr1->i1 + xscr1->chg1 < xscr2->i1) { | |
313 | i1 = xscr1->i2; | |
314 | i2 = xscr2->i2 - xscr2->i1 + xscr1->i1; | |
315 | chg1 = xscr1->chg2; | |
316 | chg2 = xscr1->chg1; | |
317 | if (xdl_append_merge(&c, 1, i1, chg1, i2, chg2)) { | |
318 | xdl_cleanup_merge(changes); | |
319 | return -1; | |
320 | } | |
321 | xscr1 = xscr1->next; | |
322 | continue; | |
323 | } | |
324 | if (xscr2->i1 + xscr2->chg1 < xscr1->i1) { | |
325 | i1 = xscr1->i2 - xscr1->i1 + xscr2->i1; | |
326 | i2 = xscr2->i2; | |
327 | chg1 = xscr2->chg1; | |
328 | chg2 = xscr2->chg2; | |
329 | if (xdl_append_merge(&c, 2, i1, chg1, i2, chg2)) { | |
330 | xdl_cleanup_merge(changes); | |
331 | return -1; | |
332 | } | |
333 | xscr2 = xscr2->next; | |
334 | continue; | |
335 | } | |
336 | if (level < 1 || xscr1->i1 != xscr2->i1 || | |
337 | xscr1->chg1 != xscr2->chg1 || | |
338 | xscr1->chg2 != xscr2->chg2 || | |
339 | xdl_merge_cmp_lines(xe1, xscr1->i2, | |
340 | xe2, xscr2->i2, | |
341 | xscr1->chg2, xpp->flags)) { | |
342 | /* conflict */ | |
343 | int off = xscr1->i1 - xscr2->i1; | |
344 | int ffo = off + xscr1->chg1 - xscr2->chg1; | |
345 | ||
346 | i1 = xscr1->i2; | |
347 | i2 = xscr2->i2; | |
348 | if (off > 0) | |
349 | i1 -= off; | |
350 | else | |
351 | i2 += off; | |
352 | chg1 = xscr1->i2 + xscr1->chg2 - i1; | |
353 | chg2 = xscr2->i2 + xscr2->chg2 - i2; | |
354 | if (ffo > 0) | |
355 | chg2 += ffo; | |
356 | else | |
357 | chg1 -= ffo; | |
358 | if (xdl_append_merge(&c, 0, i1, chg1, i2, chg2)) { | |
359 | xdl_cleanup_merge(changes); | |
360 | return -1; | |
361 | } | |
362 | } | |
363 | ||
364 | i1 = xscr1->i1 + xscr1->chg1; | |
365 | i2 = xscr2->i1 + xscr2->chg1; | |
366 | ||
98e6da8a | 367 | if (i1 >= i2) |
710daa83 | 368 | xscr2 = xscr2->next; |
98e6da8a | 369 | if (i2 >= i1) |
857b933e | 370 | xscr1 = xscr1->next; |
857b933e JS |
371 | } |
372 | while (xscr1) { | |
373 | if (!changes) | |
374 | changes = c; | |
375 | i1 = xscr1->i2; | |
376 | i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec; | |
377 | chg1 = xscr1->chg2; | |
378 | chg2 = xscr1->chg1; | |
379 | if (xdl_append_merge(&c, 1, i1, chg1, i2, chg2)) { | |
380 | xdl_cleanup_merge(changes); | |
381 | return -1; | |
382 | } | |
383 | xscr1 = xscr1->next; | |
384 | } | |
385 | while (xscr2) { | |
386 | if (!changes) | |
387 | changes = c; | |
388 | i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec; | |
389 | i2 = xscr2->i2; | |
390 | chg1 = xscr2->chg1; | |
391 | chg2 = xscr2->chg2; | |
392 | if (xdl_append_merge(&c, 2, i1, chg1, i2, chg2)) { | |
393 | xdl_cleanup_merge(changes); | |
394 | return -1; | |
395 | } | |
396 | xscr2 = xscr2->next; | |
397 | } | |
398 | if (!changes) | |
399 | changes = c; | |
400 | /* refine conflicts */ | |
f407f14d JS |
401 | if (level > 1 && |
402 | (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 || | |
403 | xdl_simplify_non_conflicts(xe1, changes) < 0)) { | |
857b933e JS |
404 | xdl_cleanup_merge(changes); |
405 | return -1; | |
406 | } | |
407 | /* output */ | |
408 | if (result) { | |
409 | int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2, | |
410 | changes, NULL); | |
411 | result->ptr = xdl_malloc(size); | |
412 | if (!result->ptr) { | |
413 | xdl_cleanup_merge(changes); | |
414 | return -1; | |
415 | } | |
416 | result->size = size; | |
417 | xdl_fill_merge_buffer(xe1, name1, xe2, name2, changes, | |
418 | result->ptr); | |
419 | } | |
420 | return xdl_cleanup_merge(changes); | |
421 | } | |
422 | ||
423 | int xdl_merge(mmfile_t *orig, mmfile_t *mf1, const char *name1, | |
424 | mmfile_t *mf2, const char *name2, | |
425 | xpparam_t const *xpp, int level, mmbuffer_t *result) { | |
426 | xdchange_t *xscr1, *xscr2; | |
427 | xdfenv_t xe1, xe2; | |
53a7085a | 428 | int status; |
857b933e JS |
429 | |
430 | result->ptr = NULL; | |
431 | result->size = 0; | |
432 | ||
433 | if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 || | |
434 | xdl_do_diff(orig, mf2, xpp, &xe2) < 0) { | |
435 | return -1; | |
436 | } | |
437 | if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 || | |
438 | xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 || | |
439 | xdl_build_script(&xe1, &xscr1) < 0) { | |
440 | xdl_free_env(&xe1); | |
441 | return -1; | |
442 | } | |
443 | if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 || | |
444 | xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 || | |
445 | xdl_build_script(&xe2, &xscr2) < 0) { | |
446 | xdl_free_env(&xe2); | |
447 | return -1; | |
448 | } | |
53a7085a | 449 | status = 0; |
857b933e JS |
450 | if (xscr1 || xscr2) { |
451 | if (!xscr1) { | |
452 | result->ptr = xdl_malloc(mf2->size); | |
453 | memcpy(result->ptr, mf2->ptr, mf2->size); | |
454 | result->size = mf2->size; | |
455 | } else if (!xscr2) { | |
456 | result->ptr = xdl_malloc(mf1->size); | |
457 | memcpy(result->ptr, mf1->ptr, mf1->size); | |
458 | result->size = mf1->size; | |
53a7085a JH |
459 | } else { |
460 | status = xdl_do_merge(&xe1, xscr1, name1, | |
461 | &xe2, xscr2, name2, | |
462 | level, xpp, result); | |
857b933e JS |
463 | } |
464 | xdl_free_script(xscr1); | |
465 | xdl_free_script(xscr2); | |
466 | } | |
467 | xdl_free_env(&xe1); | |
468 | xdl_free_env(&xe2); | |
469 | ||
53a7085a | 470 | return status; |
857b933e | 471 | } |