1#include "cache.h"
2#include "commit.h"
3#include "diff.h"
4#include "diffcore.h"
5#include "quote.h"
6static int uninteresting(struct diff_filepair *p)
8{
9 if (diff_unmodified_pair(p))
10 return 1;
11 if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
12 return 1;
13 return 0;
14}
15static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
17{
18 struct diff_queue_struct *q = &diff_queued_diff;
19 struct combine_diff_path *p;
20 int i;
21 if (!n) {
23 struct combine_diff_path *list = NULL, **tail = &list;
24 for (i = 0; i < q->nr; i++) {
25 int len;
26 const char *path;
27 if (uninteresting(q->queue[i]))
28 continue;
29 path = q->queue[i]->two->path;
30 len = strlen(path);
31 p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
33 p->path = (char*) &(p->parent_sha1[num_parent][0]);
34 memcpy(p->path, path, len);
35 p->path[len] = 0;
36 p->len = len;
37 p->next = NULL;
38 memcpy(p->sha1, q->queue[i]->two->sha1, 20);
39 memcpy(p->parent_sha1[n], q->queue[i]->one->sha1, 20);
40 *tail = p;
41 tail = &p->next;
42 }
43 return list;
44 }
45 for (p = curr; p; p = p->next) {
47 int found = 0;
48 if (!p->len)
49 continue;
50 for (i = 0; i < q->nr; i++) {
51 const char *path;
52 int len;
53 if (uninteresting(q->queue[i]))
55 continue;
56 path = q->queue[i]->two->path;
57 len = strlen(path);
58 if (len == p->len && !memcmp(path, p->path, len)) {
59 found = 1;
60 memcpy(p->parent_sha1[n],
61 q->queue[i]->one->sha1, 20);
62 break;
63 }
64 }
65 if (!found)
66 p->len = 0;
67 }
68 return curr;
69}
70struct lline {
72 struct lline *next;
73 int len;
74 unsigned long parent_map;
75 char line[FLEX_ARRAY];
76};
77struct sline {
79 struct lline *lost_head, **lost_tail;
80 char *bol;
81 int len;
82 unsigned long flag;
83};
84static char *grab_blob(const unsigned char *sha1, unsigned long *size)
86{
87 char *blob;
88 char type[20];
89 if (!memcmp(sha1, null_sha1, 20)) {
90 /* deleted blob */
91 *size = 0;
92 return xcalloc(1, 1);
93 }
94 blob = read_sha1_file(sha1, type, size);
95 if (strcmp(type, "blob"))
96 die("object '%s' is not a blob!", sha1_to_hex(sha1));
97 return blob;
98}
99#define TMPPATHLEN 50
101#define MAXLINELEN 10240
102static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
104{
105 int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
106 if (fd < 0)
107 die("unable to create temp-file");
108 if (write(fd, blob, size) != size)
109 die("unable to write temp-file");
110 close(fd);
111}
112static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
114{
115 unsigned long size;
116 void *blob;
117 blob = grab_blob(sha1, &size);
118 write_to_temp_file(tmpfile, blob, size);
119 free(blob);
120}
121static int parse_num(char **cp_p, unsigned int *num_p)
123{
124 char *cp = *cp_p;
125 unsigned int num = 0;
126 int read_some;
127 while ('0' <= *cp && *cp <= '9')
129 num = num * 10 + *cp++ - '0';
130 if (!(read_some = cp - *cp_p))
131 return -1;
132 *cp_p = cp;
133 *num_p = num;
134 return 0;
135}
136static int parse_hunk_header(char *line, int len,
138 unsigned int *ob, unsigned int *on,
139 unsigned int *nb, unsigned int *nn)
140{
141 char *cp;
142 cp = line + 4;
143 if (parse_num(&cp, ob)) {
144 bad_line:
145 return error("malformed diff output: %s", line);
146 }
147 if (*cp == ',') {
148 cp++;
149 if (parse_num(&cp, on))
150 goto bad_line;
151 }
152 else
153 *on = 1;
154 if (*cp++ != ' ' || *cp++ != '+')
155 goto bad_line;
156 if (parse_num(&cp, nb))
157 goto bad_line;
158 if (*cp == ',') {
159 cp++;
160 if (parse_num(&cp, nn))
161 goto bad_line;
162 }
163 else
164 *nn = 1;
165 return -!!memcmp(cp, " @@", 3);
166}
167static void append_lost(struct sline *sline, int n, const char *line)
169{
170 struct lline *lline;
171 int len = strlen(line);
172 unsigned long this_mask = (1UL<<n);
173 if (line[len-1] == '\n')
174 len--;
175 /* Check to see if we can squash things */
177 if (sline->lost_head) {
178 struct lline *last_one = NULL;
179 /* We cannot squash it with earlier one */
180 for (lline = sline->lost_head;
181 lline;
182 lline = lline->next)
183 if (lline->parent_map & this_mask)
184 last_one = lline;
185 lline = last_one ? last_one->next : sline->lost_head;
186 while (lline) {
187 if (lline->len == len &&
188 !memcmp(lline->line, line, len)) {
189 lline->parent_map |= this_mask;
190 return;
191 }
192 lline = lline->next;
193 }
194 }
195 lline = xmalloc(sizeof(*lline) + len + 1);
197 lline->len = len;
198 lline->next = NULL;
199 lline->parent_map = this_mask;
200 memcpy(lline->line, line, len);
201 lline->line[len] = 0;
202 *sline->lost_tail = lline;
203 sline->lost_tail = &lline->next;
204}
205static void combine_diff(const unsigned char *parent, const char *ourtmp,
207 struct sline *sline, int cnt, int n)
208{
209 FILE *in;
210 char parent_tmp[TMPPATHLEN];
211 char cmd[TMPPATHLEN * 2 + 1024];
212 char line[MAXLINELEN];
213 unsigned int lno, ob, on, nb, nn;
214 unsigned long pmask = ~(1UL << n);
215 struct sline *lost_bucket = NULL;
216 write_temp_blob(parent_tmp, parent);
218 sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
219 parent_tmp, ourtmp);
220 in = popen(cmd, "r");
221 if (!in)
222 return;
223 lno = 1;
225 while (fgets(line, sizeof(line), in) != NULL) {
226 int len = strlen(line);
227 if (5 < len && !memcmp("@@ -", line, 4)) {
228 if (parse_hunk_header(line, len,
229 &ob, &on, &nb, &nn))
230 break;
231 lno = nb;
232 if (!nb) {
233 /* @@ -1,2 +0,0 @@ to remove the
234 * first two lines...
235 */
236 nb = 1;
237 }
238 if (nn == 0)
239 lost_bucket = &sline[nb];
240 else
241 lost_bucket = &sline[nb-1];
242 continue;
243 }
244 if (!lost_bucket)
245 continue;
246 switch (line[0]) {
247 case '-':
248 append_lost(lost_bucket, n, line+1);
249 break;
250 case '+':
251 sline[lno-1].flag &= pmask;
252 lno++;
253 break;
254 }
255 }
256 fclose(in);
257 unlink(parent_tmp);
258}
259static unsigned long context = 3;
261static char combine_marker = '@';
262static int interesting(struct sline *sline, unsigned long all_mask)
264{
265 return ((sline->flag & all_mask) != all_mask || sline->lost_head);
266}
267static unsigned long adjust_hunk_tail(struct sline *sline,
269 unsigned long all_mask,
270 unsigned long hunk_begin,
271 unsigned long i)
272{
273 /* i points at the first uninteresting line.
274 * If the last line of the hunk was interesting
275 * only because it has some deletion, then
276 * it is not all that interesting for the
277 * purpose of giving trailing context lines.
278 */
279 if ((hunk_begin + 1 <= i) &&
280 ((sline[i-1].flag & all_mask) == all_mask))
281 i--;
282 return i;
283}
284static unsigned long next_interesting(struct sline *sline,
286 unsigned long mark,
287 unsigned long i,
288 unsigned long cnt,
289 int uninteresting)
290{
291 while (i < cnt)
292 if (uninteresting ?
293 !(sline[i].flag & mark) :
294 (sline[i].flag & mark))
295 return i;
296 else
297 i++;
298 return cnt;
299}
300static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
302{
303 unsigned long all_mask = (1UL<<num_parent) - 1;
304 unsigned long mark = (1UL<<num_parent);
305 unsigned long i;
306 i = next_interesting(sline, mark, 0, cnt, 0);
308 if (cnt <= i)
309 return 0;
310 while (i < cnt) {
312 unsigned long j = (context < i) ? (i - context) : 0;
313 unsigned long k;
314 while (j < i)
315 sline[j++].flag |= mark;
316 again:
318 j = next_interesting(sline, mark, i, cnt, 1);
319 if (cnt <= j)
320 break; /* the rest are all interesting */
321 /* lookahead context lines */
323 k = next_interesting(sline, mark, j, cnt, 0);
324 j = adjust_hunk_tail(sline, all_mask, i, j);
325 if (k < j + context) {
327 /* k is interesting and [j,k) are not, but
328 * paint them interesting because the gap is small.
329 */
330 while (j < k)
331 sline[j++].flag |= mark;
332 i = k;
333 goto again;
334 }
335 /* j is the first uninteresting line and there is
337 * no overlap beyond it within context lines.
338 */
339 i = k;
340 k = (j + context < cnt) ? j + context : cnt;
341 while (j < k)
342 sline[j++].flag |= mark;
343 }
344 return 1;
345}
346static int make_hunks(struct sline *sline, unsigned long cnt,
348 int num_parent, int dense)
349{
350 unsigned long all_mask = (1UL<<num_parent) - 1;
351 unsigned long mark = (1UL<<num_parent);
352 unsigned long i;
353 int has_interesting = 0;
354 for (i = 0; i < cnt; i++) {
356 if (interesting(&sline[i], all_mask))
357 sline[i].flag |= mark;
358 else
359 sline[i].flag &= ~mark;
360 }
361 if (!dense)
362 return give_context(sline, cnt, num_parent);
363 /* Look at each hunk, and if we have changes from only one
365 * parent, or the changes are the same from all but one
366 * parent, mark that uninteresting.
367 */
368 i = 0;
369 while (i < cnt) {
370 unsigned long j, hunk_begin, hunk_end;
371 unsigned long same_diff;
372 while (i < cnt && !(sline[i].flag & mark))
373 i++;
374 if (cnt <= i)
375 break; /* No more interesting hunks */
376 hunk_begin = i;
377 for (j = i + 1; j < cnt; j++) {
378 if (!(sline[j].flag & mark)) {
379 /* Look beyond the end to see if there
380 * is an interesting line after this
381 * hunk within context span.
382 */
383 unsigned long la; /* lookahead */
384 int contin = 0;
385 la = adjust_hunk_tail(sline, all_mask,
386 hunk_begin, j);
387 la = (la + context < cnt) ?
388 (la + context) : cnt;
389 while (j <= --la) {
390 if (sline[la].flag & mark) {
391 contin = 1;
392 break;
393 }
394 }
395 if (!contin)
396 break;
397 j = la;
398 }
399 }
400 hunk_end = j;
401 /* [i..hunk_end) are interesting. Now is it really
403 * interesting? We check if there are only two versions
404 * and the result matches one of them. That is, we look
405 * at:
406 * (+) line, which records lines added to which parents;
407 * this line appears in the result.
408 * (-) line, which records from what parents the line
409 * was removed; this line does not appear in the result.
410 * then check the set of parents the result has difference
411 * from, from all lines. If there are lines that has
412 * different set of parents that the result has differences
413 * from, that means we have more than two versions.
414 *
415 * Even when we have only two versions, if the result does
416 * not match any of the parents, the it should be considered
417 * interesting. In such a case, we would have all '+' line.
418 * After passing the above "two versions" test, that would
419 * appear as "the same set of parents" to be "all parents".
420 */
421 same_diff = 0;
422 has_interesting = 0;
423 for (j = i; j < hunk_end && !has_interesting; j++) {
424 unsigned long this_diff = ~sline[j].flag & all_mask;
425 struct lline *ll = sline[j].lost_head;
426 if (this_diff) {
427 /* This has some changes. Is it the
428 * same as others?
429 */
430 if (!same_diff)
431 same_diff = this_diff;
432 else if (same_diff != this_diff) {
433 has_interesting = 1;
434 break;
435 }
436 }
437 while (ll && !has_interesting) {
438 /* Lost this line from these parents;
439 * who are they? Are they the same?
440 */
441 this_diff = ll->parent_map;
442 if (!same_diff)
443 same_diff = this_diff;
444 else if (same_diff != this_diff) {
445 has_interesting = 1;
446 }
447 ll = ll->next;
448 }
449 }
450 if (!has_interesting && same_diff != all_mask) {
452 /* This hunk is not that interesting after all */
453 for (j = hunk_begin; j < hunk_end; j++)
454 sline[j].flag &= ~mark;
455 }
456 i = hunk_end;
457 }
458 has_interesting = give_context(sline, cnt, num_parent);
460 return has_interesting;
461}
462static void dump_sline(struct sline *sline, int cnt, int num_parent)
464{
465 unsigned long mark = (1UL<<num_parent);
466 int i;
467 int lno = 0;
468 while (1) {
470 struct sline *sl = &sline[lno];
471 int hunk_end;
472 while (lno < cnt && !(sline[lno].flag & mark))
473 lno++;
474 if (cnt <= lno)
475 break;
476 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
477 if (!(sline[hunk_end].flag & mark))
478 break;
479 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
480 printf(" +%d,%d ", lno+1, hunk_end-lno);
481 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
482 putchar('\n');
483 while (lno < hunk_end) {
484 struct lline *ll;
485 int j;
486 sl = &sline[lno++];
487 ll = sl->lost_head;
488 while (ll) {
489 for (j = 0; j < num_parent; j++) {
490 if (ll->parent_map & (1UL<<j))
491 putchar('-');
492 else
493 putchar(' ');
494 }
495 puts(ll->line);
496 ll = ll->next;
497 }
498 for (j = 0; j < num_parent; j++) {
499 if ((1UL<<j) & sl->flag)
500 putchar(' ');
501 else
502 putchar('+');
503 }
504 printf("%.*s\n", sl->len, sl->bol);
505 }
506 }
507}
508static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
510 int i, int j)
511{
512 /* We have already examined parent j and we know parent i
513 * and parent j are the same, so reuse the combined result
514 * of parent j for parent i.
515 */
516 unsigned long lno, imask, jmask;
517 imask = (1UL<<i);
518 jmask = (1UL<<j);
519 for (lno = 0; lno < cnt; lno++) {
521 struct lline *ll = sline->lost_head;
522 while (ll) {
523 if (ll->parent_map & jmask)
524 ll->parent_map |= imask;
525 ll = ll->next;
526 }
527 if (!(sline->flag & jmask))
528 sline->flag &= ~imask;
529 sline++;
530 }
531}
532int show_combined_diff(struct combine_diff_path *elem, int num_parent,
534 int dense, const char *header, int show_empty)
535{
536 unsigned long size, cnt, lno;
537 char *result, *cp, *ep;
538 struct sline *sline; /* survived lines */
539 int i, show_hunks, shown_header = 0;
540 char ourtmp_buf[TMPPATHLEN];
541 char *ourtmp = ourtmp_buf;
542 /* Read the result of merge first */
544 if (memcmp(elem->sha1, null_sha1, 20)) {
545 result = grab_blob(elem->sha1, &size);
546 write_to_temp_file(ourtmp, result, size);
547 }
548 else {
549 struct stat st;
550 int fd;
551 ourtmp = elem->path;
552 if (0 <= (fd = open(ourtmp, O_RDONLY)) &&
553 !fstat(fd, &st)) {
554 int len = st.st_size;
555 int cnt = 0;
556 size = len;
558 result = xmalloc(len + 1);
559 while (cnt < len) {
560 int done = xread(fd, result+cnt, len-cnt);
561 if (done == 0)
562 break;
563 if (done < 0)
564 die("read error '%s'", ourtmp);
565 cnt += done;
566 }
567 result[len] = 0;
568 }
569 else {
570 /* deleted file */
571 size = 0;
572 result = xmalloc(1);
573 result[0] = 0;
574 ourtmp = "/dev/null";
575 }
576 if (0 <= fd)
577 close(fd);
578 }
579 for (cnt = 0, cp = result; cp - result < size; cp++) {
581 if (*cp == '\n')
582 cnt++;
583 }
584 if (result[size-1] != '\n')
585 cnt++; /* incomplete line */
586 sline = xcalloc(cnt, sizeof(*sline));
588 ep = result;
589 sline[0].bol = result;
590 for (lno = 0, cp = result; cp - result < size; cp++) {
591 if (*cp == '\n') {
592 sline[lno].lost_tail = &sline[lno].lost_head;
593 sline[lno].len = cp - sline[lno].bol;
594 sline[lno].flag = (1UL<<num_parent) - 1;
595 lno++;
596 if (lno < cnt)
597 sline[lno].bol = cp + 1;
598 }
599 }
600 if (result[size-1] != '\n') {
601 sline[cnt-1].lost_tail = &sline[cnt-1].lost_head;
602 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
603 sline[cnt-1].flag = (1UL<<num_parent) - 1;
604 }
605 for (i = 0; i < num_parent; i++) {
607 int j;
608 for (j = 0; j < i; j++) {
609 if (!memcmp(elem->parent_sha1[i],
610 elem->parent_sha1[j], 20)) {
611 reuse_combine_diff(sline, cnt, i, j);
612 break;
613 }
614 }
615 if (i <= j)
616 combine_diff(elem->parent_sha1[i], ourtmp, sline,
617 cnt, i);
618 }
619 show_hunks = make_hunks(sline, cnt, num_parent, dense);
621 if (header && (show_hunks || show_empty)) {
623 shown_header++;
624 puts(header);
625 }
626 if (show_hunks) {
627 printf("diff --%s ", dense ? "cc" : "combined");
628 if (quote_c_style(elem->path, NULL, NULL, 0))
629 quote_c_style(elem->path, NULL, stdout, 0);
630 else
631 printf("%s", elem->path);
632 putchar('\n');
633 printf("index ");
634 for (i = 0; i < num_parent; i++) {
635 printf("%s%s",
636 i ? ".." : "",
637 find_unique_abbrev(elem->parent_sha1[i],
638 DEFAULT_ABBREV));
639 }
640 printf("->%s\n",
641 find_unique_abbrev(elem->sha1, DEFAULT_ABBREV));
642 dump_sline(sline, cnt, num_parent);
643 }
644 if (ourtmp == ourtmp_buf)
645 unlink(ourtmp);
646 free(result);
647 for (i = 0; i < cnt; i++) {
649 if (sline[i].lost_head) {
650 struct lline *ll = sline[i].lost_head;
651 while (ll) {
652 struct lline *tmp = ll;
653 ll = ll->next;
654 free(tmp);
655 }
656 }
657 }
658 free(sline);
659 return shown_header;
660}
661int diff_tree_combined_merge(const unsigned char *sha1,
663 const char *header,
664 int show_empty_merge, int dense)
665{
666 struct commit *commit = lookup_commit(sha1);
667 struct diff_options diffopts;
668 struct commit_list *parents;
669 struct combine_diff_path *p, *paths = NULL;
670 int num_parent, i, num_paths;
671 diff_setup(&diffopts);
673 diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
674 diffopts.recursive = 1;
675 /* count parents */
677 for (parents = commit->parents, num_parent = 0;
678 parents;
679 parents = parents->next, num_parent++)
680 ; /* nothing */
681 /* find set of paths that everybody touches */
683 for (parents = commit->parents, i = 0;
684 parents;
685 parents = parents->next, i++) {
686 struct commit *parent = parents->item;
687 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
688 &diffopts);
689 paths = intersect_paths(paths, i, num_parent);
690 diff_flush(&diffopts);
691 }
692 /* find out surviving paths */
694 for (num_paths = 0, p = paths; p; p = p->next) {
695 if (p->len)
696 num_paths++;
697 }
698 if (num_paths || show_empty_merge) {
699 for (p = paths; p; p = p->next) {
700 if (!p->len)
701 continue;
702 if (show_combined_diff(p, num_parent, dense, header,
703 show_empty_merge))
704 header = NULL;
705 }
706 }
707 /* Clean things up */
709 while (paths) {
710 struct combine_diff_path *tmp = paths;
711 paths = paths->next;
712 free(tmp);
713 }
714 return 0;
715}