diff-tree --cc: squelch header generation on empty patch.
[git/git.git] / combine-diff.c
CommitLineData
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1#include "cache.h"
2#include "commit.h"
3#include "diff.h"
4#include "diffcore.h"
5#include "quote.h"
6
7struct path_list {
8 struct path_list *next;
9 int len;
10 char *path;
11 unsigned char sha1[20];
12 unsigned char parent_sha1[FLEX_ARRAY][20];
13};
14
15static int uninteresting(struct diff_filepair *p)
16{
17 if (diff_unmodified_pair(p))
18 return 1;
19 if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
20 return 1;
21 return 0;
22}
23
24static struct path_list *intersect_paths(struct path_list *curr,
25 int n, int num_parent)
26{
27 struct diff_queue_struct *q = &diff_queued_diff;
28 struct path_list *p;
29 int i;
30
31 if (!n) {
5290a0f8 32 struct path_list *list = NULL, **tail = &list;
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33 for (i = 0; i < q->nr; i++) {
34 int len;
35 const char *path;
36 if (uninteresting(q->queue[i]))
37 continue;
38 path = q->queue[i]->two->path;
39 len = strlen(path);
40
41 p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
42 p->path = (char*) &(p->parent_sha1[num_parent][0]);
43 memcpy(p->path, path, len);
44 p->path[len] = 0;
45 p->len = len;
46 p->next = NULL;
47 memcpy(p->sha1, q->queue[i]->two->sha1, 20);
48 memcpy(p->parent_sha1[n], q->queue[i]->one->sha1, 20);
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49 *tail = p;
50 tail = &p->next;
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51 }
52 return list;
53 }
54
55 for (p = curr; p; p = p->next) {
56 int found = 0;
57 if (!p->len)
58 continue;
59 for (i = 0; i < q->nr; i++) {
60 const char *path;
61 int len;
62
63 if (uninteresting(q->queue[i]))
64 continue;
65 path = q->queue[i]->two->path;
66 len = strlen(path);
67 if (len == p->len && !memcmp(path, p->path, len)) {
68 found = 1;
69 memcpy(p->parent_sha1[n],
70 q->queue[i]->one->sha1, 20);
71 break;
72 }
73 }
74 if (!found)
75 p->len = 0;
76 }
77 return curr;
78}
79
80struct lline {
81 struct lline *next;
82 int len;
83 unsigned long parent_map;
84 char line[FLEX_ARRAY];
85};
86
87struct sline {
88 struct lline *lost_head, **lost_tail;
89 char *bol;
90 int len;
91 unsigned long flag;
92};
93
94static char *grab_blob(const unsigned char *sha1, unsigned long *size)
95{
96 char *blob;
97 char type[20];
98 if (!memcmp(sha1, null_sha1, 20)) {
99 /* deleted blob */
100 *size = 0;
101 return xcalloc(1, 1);
102 }
103 blob = read_sha1_file(sha1, type, size);
104 if (strcmp(type, "blob"))
105 die("object '%s' is not a blob!", sha1_to_hex(sha1));
106 return blob;
107}
108
109#define TMPPATHLEN 50
110#define MAXLINELEN 10240
111
112static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
113{
114 int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
115 if (fd < 0)
116 die("unable to create temp-file");
117 if (write(fd, blob, size) != size)
118 die("unable to write temp-file");
119 close(fd);
120}
121
122static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
123{
124 unsigned long size;
125 void *blob;
126 blob = grab_blob(sha1, &size);
127 write_to_temp_file(tmpfile, blob, size);
128 free(blob);
129}
130
131static int parse_num(char **cp_p, unsigned int *num_p)
132{
133 char *cp = *cp_p;
134 unsigned int num = 0;
135 int read_some;
136
137 while ('0' <= *cp && *cp <= '9')
138 num = num * 10 + *cp++ - '0';
139 if (!(read_some = cp - *cp_p))
140 return -1;
141 *cp_p = cp;
142 *num_p = num;
143 return 0;
144}
145
146static int parse_hunk_header(char *line, int len,
147 unsigned int *ob, unsigned int *on,
148 unsigned int *nb, unsigned int *nn)
149{
150 char *cp;
151 cp = line + 4;
152 if (parse_num(&cp, ob)) {
153 bad_line:
154 return error("malformed diff output: %s", line);
155 }
156 if (*cp == ',') {
157 cp++;
158 if (parse_num(&cp, on))
159 goto bad_line;
160 }
161 else
162 *on = 1;
163 if (*cp++ != ' ' || *cp++ != '+')
164 goto bad_line;
165 if (parse_num(&cp, nb))
166 goto bad_line;
167 if (*cp == ',') {
168 cp++;
169 if (parse_num(&cp, nn))
170 goto bad_line;
171 }
172 else
173 *nn = 1;
174 return -!!memcmp(cp, " @@", 3);
175}
176
177static void append_lost(struct sline *sline, int n, const char *line)
178{
179 struct lline *lline;
180 int len = strlen(line);
181 unsigned long this_mask = (1UL<<n);
182 if (line[len-1] == '\n')
183 len--;
184
185 /* Check to see if we can squash things */
186 if (sline->lost_head) {
187 struct lline *last_one = NULL;
188 /* We cannot squash it with earlier one */
189 for (lline = sline->lost_head;
190 lline;
191 lline = lline->next)
192 if (lline->parent_map & this_mask)
193 last_one = lline;
194 lline = last_one ? last_one->next : sline->lost_head;
195 while (lline) {
196 if (lline->len == len &&
197 !memcmp(lline->line, line, len)) {
198 lline->parent_map |= this_mask;
199 return;
200 }
201 lline = lline->next;
202 }
203 }
204
205 lline = xmalloc(sizeof(*lline) + len + 1);
206 lline->len = len;
207 lline->next = NULL;
208 lline->parent_map = this_mask;
209 memcpy(lline->line, line, len);
210 lline->line[len] = 0;
5290a0f8 211 *sline->lost_tail = lline;
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212 sline->lost_tail = &lline->next;
213}
214
215static void combine_diff(const unsigned char *parent, const char *ourtmp,
216 struct sline *sline, int cnt, int n)
217{
218 FILE *in;
219 char parent_tmp[TMPPATHLEN];
220 char cmd[TMPPATHLEN * 2 + 1024];
221 char line[MAXLINELEN];
222 unsigned int lno, ob, on, nb, nn;
223 unsigned long pmask = ~(1UL << n);
224 struct sline *lost_bucket = NULL;
225
226 write_temp_blob(parent_tmp, parent);
227 sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
228 parent_tmp, ourtmp);
229 in = popen(cmd, "r");
230 if (!in)
231 return;
232
233 lno = 1;
234 while (fgets(line, sizeof(line), in) != NULL) {
235 int len = strlen(line);
236 if (5 < len && !memcmp("@@ -", line, 4)) {
237 if (parse_hunk_header(line, len,
238 &ob, &on, &nb, &nn))
239 break;
240 lno = nb;
241 if (!nb) {
242 /* @@ -1,2 +0,0 @@ to remove the
243 * first two lines...
244 */
245 nb = 1;
246 }
247 lost_bucket = &sline[nb-1]; /* sline is 0 based */
248 continue;
249 }
250 if (!lost_bucket)
251 continue;
252 switch (line[0]) {
253 case '-':
254 append_lost(lost_bucket, n, line+1);
255 break;
256 case '+':
257 sline[lno-1].flag &= pmask;
258 lno++;
259 break;
260 }
261 }
262 fclose(in);
263 unlink(parent_tmp);
264}
265
266static unsigned long context = 3;
267static char combine_marker = '@';
268
269static int interesting(struct sline *sline, unsigned long all_mask)
270{
271 return ((sline->flag & all_mask) != all_mask || sline->lost_head);
272}
273
263eee29 274static unsigned long line_common_diff(struct sline *sline, unsigned long all_mask)
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275{
276 /*
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277 * Look at the line and see from which parents we have the
278 * same difference.
d8f4790e 279 */
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280
281 /* Lower bits of sline->flag records if the parent had this
282 * line, so XOR with all_mask gives us on-bits for parents we
283 * have differences with.
284 */
285 unsigned long common_adds = (sline->flag ^ all_mask) & all_mask;
286 unsigned long common_removes = all_mask;
287
288 /* If all the parents have this line, that also counts as
289 * having the same difference.
290 */
291 if (!common_adds)
292 common_adds = all_mask;
293
294 if (sline->lost_head) {
295 /* Lost head list records the lines removed from
296 * the parents, and parent_map records from which
297 * parent the line was removed.
298 */
299 struct lline *ll;
300 for (ll = sline->lost_head; ll; ll = ll->next) {
301 common_removes &= ll->parent_map;
302 }
303 }
304 return common_adds & common_removes;
305}
306
307static unsigned long line_all_diff(struct sline *sline, unsigned long all_mask)
308{
309 /*
310 * Look at the line and see from which parents we have some difference.
311 */
312 unsigned long different = (sline->flag ^ all_mask) & all_mask;
d8f4790e 313 if (sline->lost_head) {
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314 /* Lost head list records the lines removed from
315 * the parents, and parent_map records from which
316 * parent the line was removed.
317 */
d8f4790e 318 struct lline *ll;
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319 for (ll = sline->lost_head; ll; ll = ll->next) {
320 different |= ll->parent_map;
321 }
d8f4790e 322 }
263eee29 323 return different;
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324}
325
8828cdcb 326static int make_hunks(struct sline *sline, unsigned long cnt,
d8f4790e 327 int num_parent, int dense)
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328{
329 unsigned long all_mask = (1UL<<num_parent) - 1;
330 unsigned long mark = (1UL<<num_parent);
331 unsigned long i;
8828cdcb 332 int has_interesting = 0;
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333
334 i = 0;
335 while (i < cnt) {
336 if (interesting(&sline[i], all_mask)) {
337 unsigned long j = (context < i) ? i - context : 0;
338 while (j <= i)
339 sline[j++].flag |= mark;
340 while (++i < cnt) {
341 if (!interesting(&sline[i], all_mask))
342 break;
343 sline[i].flag |= mark;
344 }
345 j = (i + context < cnt) ? i + context : cnt;
346 while (i < j)
347 sline[i++].flag |= mark;
8828cdcb 348 has_interesting = 1;
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349 continue;
350 }
351 i++;
352 }
d8f4790e 353 if (!dense)
8828cdcb 354 return has_interesting;
d8f4790e 355
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356 /* Look at each hunk, and if we have changes from only one
357 * parent, or the changes are the same from all but one
358 * parent, mark that uninteresting.
d8f4790e 359 */
8828cdcb 360 has_interesting = 0;
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361 i = 0;
362 while (i < cnt) {
263eee29 363 int j, hunk_end, same, diff;
8828cdcb 364 unsigned long same_diff, all_diff;
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365 while (i < cnt && !(sline[i].flag & mark))
366 i++;
367 if (cnt <= i)
368 break; /* No more interesting hunks */
369 for (hunk_end = i + 1; hunk_end < cnt; hunk_end++)
370 if (!(sline[hunk_end].flag & mark))
371 break;
263eee29
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372 /* [i..hunk_end) are interesting. Now does it have
373 * the same change with all but one parent?
d8f4790e 374 */
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375 same_diff = all_mask;
376 all_diff = 0;
377 for (j = i; j < hunk_end; j++) {
378 same_diff &= line_common_diff(sline + j, all_mask);
379 all_diff |= line_all_diff(sline + j, all_mask);
380 }
381 diff = same = 0;
d8f4790e 382 for (j = 0; j < num_parent; j++) {
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383 if (same_diff & (1UL<<j))
384 same++;
385 if (all_diff & (1UL<<j))
386 diff++;
d8f4790e 387 }
263eee29 388 if ((num_parent - 1 <= same) || (diff == 1)) {
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389 /* This hunk is not that interesting after all */
390 for (j = i; j < hunk_end; j++)
391 sline[j].flag &= ~mark;
392 }
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393 else
394 has_interesting = 1;
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395 i = hunk_end;
396 }
8828cdcb 397 return has_interesting;
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398}
399
400static void dump_sline(struct sline *sline, int cnt, int num_parent)
401{
402 unsigned long mark = (1UL<<num_parent);
403 int i;
404 int lno = 0;
405
406 while (1) {
407 struct sline *sl = &sline[lno];
408 int hunk_end;
409 while (lno < cnt && !(sline[lno].flag & mark))
410 lno++;
411 if (cnt <= lno)
412 break;
413 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
414 if (!(sline[hunk_end].flag & mark))
415 break;
416 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
417 printf(" +%d,%d ", lno+1, hunk_end-lno);
418 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
419 putchar('\n');
420 while (lno < hunk_end) {
421 struct lline *ll;
422 int j;
423 sl = &sline[lno++];
424 ll = sl->lost_head;
425 while (ll) {
426 for (j = 0; j < num_parent; j++) {
427 if (ll->parent_map & (1UL<<j))
428 putchar('-');
429 else
430 putchar(' ');
431 }
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432 puts(ll->line);
433 ll = ll->next;
434 }
435 for (j = 0; j < num_parent; j++) {
436 if ((1UL<<j) & sl->flag)
437 putchar(' ');
438 else
439 putchar('+');
440 }
e2283409 441 printf("%.*s\n", sl->len, sl->bol);
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442 }
443 }
444}
445
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446static int show_combined_diff(struct path_list *elem, int num_parent,
447 int dense, const char *header, int show_empty)
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448{
449 unsigned long size, cnt, lno;
450 char *result, *cp, *ep;
451 struct sline *sline; /* survived lines */
8828cdcb 452 int i, show_hunks, shown_header = 0;
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453 char ourtmp[TMPPATHLEN];
454
455 /* Read the result of merge first */
456 result = grab_blob(elem->sha1, &size);
457 write_to_temp_file(ourtmp, result, size);
458
459 for (cnt = 0, cp = result; cp - result < size; cp++) {
460 if (*cp == '\n')
461 cnt++;
462 }
463 if (result[size-1] != '\n')
464 cnt++; /* incomplete line */
465
466 sline = xcalloc(cnt, sizeof(*sline));
467 ep = result;
468 sline[0].bol = result;
469 for (lno = 0, cp = result; cp - result < size; cp++) {
470 if (*cp == '\n') {
5290a0f8 471 sline[lno].lost_tail = &sline[lno].lost_head;
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472 sline[lno].len = cp - sline[lno].bol;
473 sline[lno].flag = (1UL<<num_parent) - 1;
474 lno++;
475 if (lno < cnt)
476 sline[lno].bol = cp + 1;
477 }
478 }
479 if (result[size-1] != '\n') {
5290a0f8 480 sline[cnt-1].lost_tail = &sline[cnt-1].lost_head;
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481 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
482 sline[cnt-1].flag = (1UL<<num_parent) - 1;
483 }
484
485 for (i = 0; i < num_parent; i++)
486 combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
487
8828cdcb 488 show_hunks = make_hunks(sline, cnt, num_parent, dense);
af3feefa 489
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490 if (header && (show_hunks || show_empty)) {
491 shown_header++;
492 puts(header);
493 }
494 if (show_hunks) {
495 printf("diff --%s ", dense ? "cc" : "combined");
496 if (quote_c_style(elem->path, NULL, NULL, 0))
497 quote_c_style(elem->path, NULL, stdout, 0);
498 else
499 printf("%s", elem->path);
500 putchar('\n');
501 dump_sline(sline, cnt, num_parent);
502 }
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503 unlink(ourtmp);
504 free(result);
505
506 for (i = 0; i < cnt; i++) {
507 if (sline[i].lost_head) {
508 struct lline *ll = sline[i].lost_head;
509 while (ll) {
510 struct lline *tmp = ll;
511 ll = ll->next;
512 free(tmp);
513 }
514 }
515 }
516 free(sline);
8828cdcb 517 return shown_header;
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518}
519
520int diff_tree_combined_merge(const unsigned char *sha1,
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521 const char *header,
522 int show_empty_merge, int dense)
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523{
524 struct commit *commit = lookup_commit(sha1);
525 struct diff_options diffopts;
526 struct commit_list *parents;
527 struct path_list *p, *paths = NULL;
528 int num_parent, i, num_paths;
529
530 diff_setup(&diffopts);
531 diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
532 diffopts.recursive = 1;
533
534 /* count parents */
535 for (parents = commit->parents, num_parent = 0;
536 parents;
537 parents = parents->next, num_parent++)
538 ; /* nothing */
539
540 /* find set of paths that everybody touches */
541 for (parents = commit->parents, i = 0;
542 parents;
543 parents = parents->next, i++) {
544 struct commit *parent = parents->item;
545 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
546 &diffopts);
547 paths = intersect_paths(paths, i, num_parent);
548 diff_flush(&diffopts);
549 }
550
551 /* find out surviving paths */
552 for (num_paths = 0, p = paths; p; p = p->next) {
553 if (p->len)
554 num_paths++;
555 }
556 if (num_paths || show_empty_merge) {
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557 for (p = paths; p; p = p->next) {
558 if (!p->len)
559 continue;
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560 if (show_combined_diff(p, num_parent, dense, header,
561 show_empty_merge))
562 header = NULL;
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563 }
564 }
565
566 /* Clean things up */
567 while (paths) {
568 struct path_list *tmp = paths;
569 paths = paths->next;
570 free(tmp);
571 }
572 return 0;
573}