a608faf23217fadd42105d9eab96b28474930b69
1#include "cache.h"
2#include "tag.h"
3#include "commit.h"
4int save_commit_buffer = 1;
6struct sort_node
8{
9 /*
10 * the number of children of the associated commit
11 * that also occur in the list being sorted.
12 */
13 unsigned int indegree;
14 /*
16 * reference to original list item that we will re-use
17 * on output.
18 */
19 struct commit_list * list_item;
20};
22const char *commit_type = "commit";
24struct cmt_fmt_map {
26 const char *n;
27 size_t cmp_len;
28 enum cmit_fmt v;
29} cmt_fmts[] = {
30 { "raw", 1, CMIT_FMT_RAW },
31 { "medium", 1, CMIT_FMT_MEDIUM },
32 { "short", 1, CMIT_FMT_SHORT },
33 { "email", 1, CMIT_FMT_EMAIL },
34 { "full", 5, CMIT_FMT_FULL },
35 { "fuller", 5, CMIT_FMT_FULLER },
36 { "oneline", 1, CMIT_FMT_ONELINE },
37};
38enum cmit_fmt get_commit_format(const char *arg)
40{
41 int i;
42 if (!arg || !*arg)
44 return CMIT_FMT_DEFAULT;
45 if (*arg == '=')
46 arg++;
47 for (i = 0; i < ARRAY_SIZE(cmt_fmts); i++) {
48 if (!strncmp(arg, cmt_fmts[i].n, cmt_fmts[i].cmp_len))
49 return cmt_fmts[i].v;
50 }
51 die("invalid --pretty format: %s", arg);
53}
54static struct commit *check_commit(struct object *obj,
56 const unsigned char *sha1,
57 int quiet)
58{
59 if (obj->type != TYPE_COMMIT) {
60 if (!quiet)
61 error("Object %s is a %s, not a commit",
62 sha1_to_hex(sha1), typename(obj->type));
63 return NULL;
64 }
65 return (struct commit *) obj;
66}
67struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
69 int quiet)
70{
71 struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
72 if (!obj)
74 return NULL;
75 return check_commit(obj, sha1, quiet);
76}
77struct commit *lookup_commit_reference(const unsigned char *sha1)
79{
80 return lookup_commit_reference_gently(sha1, 0);
81}
82struct commit *lookup_commit(const unsigned char *sha1)
84{
85 struct object *obj = lookup_object(sha1);
86 if (!obj) {
87 struct commit *ret = alloc_commit_node();
88 created_object(sha1, &ret->object);
89 ret->object.type = TYPE_COMMIT;
90 return ret;
91 }
92 if (!obj->type)
93 obj->type = TYPE_COMMIT;
94 return check_commit(obj, sha1, 0);
95}
96static unsigned long parse_commit_date(const char *buf)
98{
99 unsigned long date;
100 if (memcmp(buf, "author", 6))
102 return 0;
103 while (*buf++ != '\n')
104 /* nada */;
105 if (memcmp(buf, "committer", 9))
106 return 0;
107 while (*buf++ != '>')
108 /* nada */;
109 date = strtoul(buf, NULL, 10);
110 if (date == ULONG_MAX)
111 date = 0;
112 return date;
113}
114static struct commit_graft **commit_graft;
116static int commit_graft_alloc, commit_graft_nr;
117static int commit_graft_pos(const unsigned char *sha1)
119{
120 int lo, hi;
121 lo = 0;
122 hi = commit_graft_nr;
123 while (lo < hi) {
124 int mi = (lo + hi) / 2;
125 struct commit_graft *graft = commit_graft[mi];
126 int cmp = memcmp(sha1, graft->sha1, 20);
127 if (!cmp)
128 return mi;
129 if (cmp < 0)
130 hi = mi;
131 else
132 lo = mi + 1;
133 }
134 return -lo - 1;
135}
136int register_commit_graft(struct commit_graft *graft, int ignore_dups)
138{
139 int pos = commit_graft_pos(graft->sha1);
140
141 if (0 <= pos) {
142 if (ignore_dups)
143 free(graft);
144 else {
145 free(commit_graft[pos]);
146 commit_graft[pos] = graft;
147 }
148 return 1;
149 }
150 pos = -pos - 1;
151 if (commit_graft_alloc <= ++commit_graft_nr) {
152 commit_graft_alloc = alloc_nr(commit_graft_alloc);
153 commit_graft = xrealloc(commit_graft,
154 sizeof(*commit_graft) *
155 commit_graft_alloc);
156 }
157 if (pos < commit_graft_nr)
158 memmove(commit_graft + pos + 1,
159 commit_graft + pos,
160 (commit_graft_nr - pos - 1) *
161 sizeof(*commit_graft));
162 commit_graft[pos] = graft;
163 return 0;
164}
165struct commit_graft *read_graft_line(char *buf, int len)
167{
168 /* The format is just "Commit Parent1 Parent2 ...\n" */
169 int i;
170 struct commit_graft *graft = NULL;
171 if (buf[len-1] == '\n')
173 buf[--len] = 0;
174 if (buf[0] == '#' || buf[0] == '\0')
175 return NULL;
176 if ((len + 1) % 41) {
177 bad_graft_data:
178 error("bad graft data: %s", buf);
179 free(graft);
180 return NULL;
181 }
182 i = (len + 1) / 41 - 1;
183 graft = xmalloc(sizeof(*graft) + 20 * i);
184 graft->nr_parent = i;
185 if (get_sha1_hex(buf, graft->sha1))
186 goto bad_graft_data;
187 for (i = 40; i < len; i += 41) {
188 if (buf[i] != ' ')
189 goto bad_graft_data;
190 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
191 goto bad_graft_data;
192 }
193 return graft;
194}
195int read_graft_file(const char *graft_file)
197{
198 FILE *fp = fopen(graft_file, "r");
199 char buf[1024];
200 if (!fp)
201 return -1;
202 while (fgets(buf, sizeof(buf), fp)) {
203 /* The format is just "Commit Parent1 Parent2 ...\n" */
204 int len = strlen(buf);
205 struct commit_graft *graft = read_graft_line(buf, len);
206 if (!graft)
207 continue;
208 if (register_commit_graft(graft, 1))
209 error("duplicate graft data: %s", buf);
210 }
211 fclose(fp);
212 return 0;
213}
214static void prepare_commit_graft(void)
216{
217 static int commit_graft_prepared;
218 char *graft_file;
219 if (commit_graft_prepared)
221 return;
222 graft_file = get_graft_file();
223 read_graft_file(graft_file);
224 commit_graft_prepared = 1;
225}
226static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
228{
229 int pos;
230 prepare_commit_graft();
231 pos = commit_graft_pos(sha1);
232 if (pos < 0)
233 return NULL;
234 return commit_graft[pos];
235}
236int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
238{
239 char *tail = buffer;
240 char *bufptr = buffer;
241 unsigned char parent[20];
242 struct commit_list **pptr;
243 struct commit_graft *graft;
244 unsigned n_refs = 0;
245 if (item->object.parsed)
247 return 0;
248 item->object.parsed = 1;
249 tail += size;
250 if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
251 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
252 if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
253 return error("bad tree pointer in commit %s",
254 sha1_to_hex(item->object.sha1));
255 item->tree = lookup_tree(parent);
256 if (item->tree)
257 n_refs++;
258 bufptr += 46; /* "tree " + "hex sha1" + "\n" */
259 pptr = &item->parents;
260 graft = lookup_commit_graft(item->object.sha1);
262 while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
263 struct commit *new_parent;
264 if (tail <= bufptr + 48 ||
266 get_sha1_hex(bufptr + 7, parent) ||
267 bufptr[47] != '\n')
268 return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
269 bufptr += 48;
270 if (graft)
271 continue;
272 new_parent = lookup_commit(parent);
273 if (new_parent) {
274 pptr = &commit_list_insert(new_parent, pptr)->next;
275 n_refs++;
276 }
277 }
278 if (graft) {
279 int i;
280 struct commit *new_parent;
281 for (i = 0; i < graft->nr_parent; i++) {
282 new_parent = lookup_commit(graft->parent[i]);
283 if (!new_parent)
284 continue;
285 pptr = &commit_list_insert(new_parent, pptr)->next;
286 n_refs++;
287 }
288 }
289 item->date = parse_commit_date(bufptr);
290 if (track_object_refs) {
292 unsigned i = 0;
293 struct commit_list *p;
294 struct object_refs *refs = alloc_object_refs(n_refs);
295 if (item->tree)
296 refs->ref[i++] = &item->tree->object;
297 for (p = item->parents; p; p = p->next)
298 refs->ref[i++] = &p->item->object;
299 set_object_refs(&item->object, refs);
300 }
301 return 0;
303}
304int parse_commit(struct commit *item)
306{
307 char type[20];
308 void *buffer;
309 unsigned long size;
310 int ret;
311 if (item->object.parsed)
313 return 0;
314 buffer = read_sha1_file(item->object.sha1, type, &size);
315 if (!buffer)
316 return error("Could not read %s",
317 sha1_to_hex(item->object.sha1));
318 if (strcmp(type, commit_type)) {
319 free(buffer);
320 return error("Object %s not a commit",
321 sha1_to_hex(item->object.sha1));
322 }
323 ret = parse_commit_buffer(item, buffer, size);
324 if (save_commit_buffer && !ret) {
325 item->buffer = buffer;
326 return 0;
327 }
328 free(buffer);
329 return ret;
330}
331struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
333{
334 struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
335 new_list->item = item;
336 new_list->next = *list_p;
337 *list_p = new_list;
338 return new_list;
339}
340void free_commit_list(struct commit_list *list)
342{
343 while (list) {
344 struct commit_list *temp = list;
345 list = temp->next;
346 free(temp);
347 }
348}
349struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
351{
352 struct commit_list **pp = list;
353 struct commit_list *p;
354 while ((p = *pp) != NULL) {
355 if (p->item->date < item->date) {
356 break;
357 }
358 pp = &p->next;
359 }
360 return commit_list_insert(item, pp);
361}
362
364void sort_by_date(struct commit_list **list)
365{
366 struct commit_list *ret = NULL;
367 while (*list) {
368 insert_by_date((*list)->item, &ret);
369 *list = (*list)->next;
370 }
371 *list = ret;
372}
373struct commit *pop_most_recent_commit(struct commit_list **list,
375 unsigned int mark)
376{
377 struct commit *ret = (*list)->item;
378 struct commit_list *parents = ret->parents;
379 struct commit_list *old = *list;
380 *list = (*list)->next;
382 free(old);
383 while (parents) {
385 struct commit *commit = parents->item;
386 parse_commit(commit);
387 if (!(commit->object.flags & mark)) {
388 commit->object.flags |= mark;
389 insert_by_date(commit, list);
390 }
391 parents = parents->next;
392 }
393 return ret;
394}
395void clear_commit_marks(struct commit *commit, unsigned int mark)
397{
398 struct commit_list *parents;
399 if (!commit)
401 return;
402 parents = commit->parents;
403 commit->object.flags &= ~mark;
404 while (parents) {
405 clear_commit_marks(parents->item, mark);
406 parents = parents->next;
407 }
408}
409/*
411 * Generic support for pretty-printing the header
412 */
413static int get_one_line(const char *msg, unsigned long len)
414{
415 int ret = 0;
416 while (len--) {
418 char c = *msg++;
419 if (!c)
420 break;
421 ret++;
422 if (c == '\n')
423 break;
424 }
425 return ret;
426}
427static int is_rfc2047_special(char ch)
429{
430 return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
431}
432static int add_rfc2047(char *buf, const char *line, int len)
434{
435 char *bp = buf;
436 int i, needquote;
437 static const char q_utf8[] = "=?utf-8?q?";
438 for (i = needquote = 0; !needquote && i < len; i++) {
440 unsigned ch = line[i];
441 if (ch & 0x80)
442 needquote++;
443 if ((i + 1 < len) &&
444 (ch == '=' && line[i+1] == '?'))
445 needquote++;
446 }
447 if (!needquote)
448 return sprintf(buf, "%.*s", len, line);
449 memcpy(bp, q_utf8, sizeof(q_utf8)-1);
451 bp += sizeof(q_utf8)-1;
452 for (i = 0; i < len; i++) {
453 unsigned ch = line[i] & 0xFF;
454 if (is_rfc2047_special(ch)) {
455 sprintf(bp, "=%02X", ch);
456 bp += 3;
457 }
458 else if (ch == ' ')
459 *bp++ = '_';
460 else
461 *bp++ = ch;
462 }
463 memcpy(bp, "?=", 2);
464 bp += 2;
465 return bp - buf;
466}
467static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
469{
470 char *date;
471 int namelen;
472 unsigned long time;
473 int tz, ret;
474 const char *filler = " ";
475 if (fmt == CMIT_FMT_ONELINE)
477 return 0;
478 date = strchr(line, '>');
479 if (!date)
480 return 0;
481 namelen = ++date - line;
482 time = strtoul(date, &date, 10);
483 tz = strtol(date, NULL, 10);
484 if (fmt == CMIT_FMT_EMAIL) {
486 char *name_tail = strchr(line, '<');
487 int display_name_length;
488 if (!name_tail)
489 return 0;
490 while (line < name_tail && isspace(name_tail[-1]))
491 name_tail--;
492 display_name_length = name_tail - line;
493 filler = "";
494 strcpy(buf, "From: ");
495 ret = strlen(buf);
496 ret += add_rfc2047(buf + ret, line, display_name_length);
497 memcpy(buf + ret, name_tail, namelen - display_name_length);
498 ret += namelen - display_name_length;
499 buf[ret++] = '\n';
500 }
501 else {
502 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
503 (fmt == CMIT_FMT_FULLER) ? 4 : 0,
504 filler, namelen, line);
505 }
506 switch (fmt) {
507 case CMIT_FMT_MEDIUM:
508 ret += sprintf(buf + ret, "Date: %s\n", show_date(time, tz));
509 break;
510 case CMIT_FMT_EMAIL:
511 ret += sprintf(buf + ret, "Date: %s\n",
512 show_rfc2822_date(time, tz));
513 break;
514 case CMIT_FMT_FULLER:
515 ret += sprintf(buf + ret, "%sDate: %s\n", what, show_date(time, tz));
516 break;
517 default:
518 /* notin' */
519 break;
520 }
521 return ret;
522}
523static int is_empty_line(const char *line, int *len_p)
525{
526 int len = *len_p;
527 while (len && isspace(line[len-1]))
528 len--;
529 *len_p = len;
530 return !len;
531}
532static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
534{
535 struct commit_list *parent = commit->parents;
536 int offset;
537 if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
539 !parent || !parent->next)
540 return 0;
541 offset = sprintf(buf, "Merge:");
543 while (parent) {
545 struct commit *p = parent->item;
546 const char *hex = abbrev
547 ? find_unique_abbrev(p->object.sha1, abbrev)
548 : sha1_to_hex(p->object.sha1);
549 const char *dots = (abbrev && strlen(hex) != 40) ? "..." : "";
550 parent = parent->next;
551 offset += sprintf(buf + offset, " %s%s", hex, dots);
553 }
554 buf[offset++] = '\n';
555 return offset;
556}
557unsigned long pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit, unsigned long len, char *buf, unsigned long space, int abbrev, const char *subject, const char *after_subject)
559{
560 int hdr = 1, body = 0;
561 unsigned long offset = 0;
562 int indent = 4;
563 int parents_shown = 0;
564 const char *msg = commit->buffer;
565 int plain_non_ascii = 0;
566 if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
568 indent = 0;
569 /* After-subject is used to pass in Content-Type: multipart
571 * MIME header; in that case we do not have to do the
572 * plaintext content type even if the commit message has
573 * non 7-bit ASCII character. Otherwise, check if we need
574 * to say this is not a 7-bit ASCII.
575 */
576 if (fmt == CMIT_FMT_EMAIL && !after_subject) {
577 int i, ch, in_body;
578 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
580 if (!in_body) {
581 /* author could be non 7-bit ASCII but
582 * the log may so; skip over the
583 * header part first.
584 */
585 if (ch == '\n' &&
586 i + 1 < len && msg[i+1] == '\n')
587 in_body = 1;
588 }
589 else if (ch & 0x80) {
590 plain_non_ascii = 1;
591 break;
592 }
593 }
594 }
595 for (;;) {
597 const char *line = msg;
598 int linelen = get_one_line(msg, len);
599 if (!linelen)
601 break;
602 /*
604 * We want some slop for indentation and a possible
605 * final "...". Thus the "+ 20".
606 */
607 if (offset + linelen + 20 > space) {
608 memcpy(buf + offset, " ...\n", 8);
609 offset += 8;
610 break;
611 }
612 msg += linelen;
614 len -= linelen;
615 if (hdr) {
616 if (linelen == 1) {
617 hdr = 0;
618 if ((fmt != CMIT_FMT_ONELINE) && !subject)
619 buf[offset++] = '\n';
620 continue;
621 }
622 if (fmt == CMIT_FMT_RAW) {
623 memcpy(buf + offset, line, linelen);
624 offset += linelen;
625 continue;
626 }
627 if (!memcmp(line, "parent ", 7)) {
628 if (linelen != 48)
629 die("bad parent line in commit");
630 continue;
631 }
632 if (!parents_shown) {
634 offset += add_merge_info(fmt, buf + offset,
635 commit, abbrev);
636 parents_shown = 1;
637 continue;
638 }
639 /*
640 * MEDIUM == DEFAULT shows only author with dates.
641 * FULL shows both authors but not dates.
642 * FULLER shows both authors and dates.
643 */
644 if (!memcmp(line, "author ", 7))
645 offset += add_user_info("Author", fmt,
646 buf + offset,
647 line + 7);
648 if (!memcmp(line, "committer ", 10) &&
649 (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
650 offset += add_user_info("Commit", fmt,
651 buf + offset,
652 line + 10);
653 continue;
654 }
655 if (is_empty_line(line, &linelen)) {
657 if (!body)
658 continue;
659 if (subject)
660 continue;
661 if (fmt == CMIT_FMT_SHORT)
662 break;
663 } else {
664 body = 1;
665 }
666 if (subject) {
668 int slen = strlen(subject);
669 memcpy(buf + offset, subject, slen);
670 offset += slen;
671 offset += add_rfc2047(buf + offset, line, linelen);
672 }
673 else {
674 memset(buf + offset, ' ', indent);
675 memcpy(buf + offset + indent, line, linelen);
676 offset += linelen + indent;
677 }
678 buf[offset++] = '\n';
679 if (fmt == CMIT_FMT_ONELINE)
680 break;
681 if (subject && plain_non_ascii) {
682 static const char header[] =
683 "Content-Type: text/plain; charset=UTF-8\n"
684 "Content-Transfer-Encoding: 8bit\n";
685 memcpy(buf + offset, header, sizeof(header)-1);
686 offset += sizeof(header)-1;
687 }
688 if (after_subject) {
689 int slen = strlen(after_subject);
690 if (slen > space - offset - 1)
691 slen = space - offset - 1;
692 memcpy(buf + offset, after_subject, slen);
693 offset += slen;
694 after_subject = NULL;
695 }
696 subject = NULL;
697 }
698 while (offset && isspace(buf[offset-1]))
699 offset--;
700 /* Make sure there is an EOLN for the non-oneline case */
701 if (fmt != CMIT_FMT_ONELINE)
702 buf[offset++] = '\n';
703 buf[offset] = '\0';
704 return offset;
705}
706struct commit *pop_commit(struct commit_list **stack)
708{
709 struct commit_list *top = *stack;
710 struct commit *item = top ? top->item : NULL;
711 if (top) {
713 *stack = top->next;
714 free(top);
715 }
716 return item;
717}
718int count_parents(struct commit * commit)
720{
721 int count = 0;
722 struct commit_list * parents = commit->parents;
723 for (count=0;parents; parents=parents->next,count++)
724 ;
725 return count;
726}
727void topo_sort_default_setter(struct commit *c, void *data)
729{
730 c->util = data;
731}
732void *topo_sort_default_getter(struct commit *c)
734{
735 return c->util;
736}
737/*
739 * Performs an in-place topological sort on the list supplied.
740 */
741void sort_in_topological_order(struct commit_list ** list, int lifo)
742{
743 sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
744 topo_sort_default_getter);
745}
746void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
748 topo_sort_set_fn_t setter,
749 topo_sort_get_fn_t getter)
750{
751 struct commit_list * next = *list;
752 struct commit_list * work = NULL, **insert;
753 struct commit_list ** pptr = list;
754 struct sort_node * nodes;
755 struct sort_node * next_nodes;
756 int count = 0;
757 /* determine the size of the list */
759 while (next) {
760 next = next->next;
761 count++;
762 }
763
764 if (!count)
765 return;
766 /* allocate an array to help sort the list */
767 nodes = xcalloc(count, sizeof(*nodes));
768 /* link the list to the array */
769 next_nodes = nodes;
770 next=*list;
771 while (next) {
772 next_nodes->list_item = next;
773 setter(next->item, next_nodes);
774 next_nodes++;
775 next = next->next;
776 }
777 /* update the indegree */
778 next=*list;
779 while (next) {
780 struct commit_list * parents = next->item->parents;
781 while (parents) {
782 struct commit * parent=parents->item;
783 struct sort_node * pn = (struct sort_node *) getter(parent);
784 if (pn)
786 pn->indegree++;
787 parents=parents->next;
788 }
789 next=next->next;
790 }
791 /*
792 * find the tips
793 *
794 * tips are nodes not reachable from any other node in the list
795 *
796 * the tips serve as a starting set for the work queue.
797 */
798 next=*list;
799 insert = &work;
800 while (next) {
801 struct sort_node * node = (struct sort_node *) getter(next->item);
802 if (node->indegree == 0) {
804 insert = &commit_list_insert(next->item, insert)->next;
805 }
806 next=next->next;
807 }
808 /* process the list in topological order */
810 if (!lifo)
811 sort_by_date(&work);
812 while (work) {
813 struct commit * work_item = pop_commit(&work);
814 struct sort_node * work_node = (struct sort_node *) getter(work_item);
815 struct commit_list * parents = work_item->parents;
816 while (parents) {
818 struct commit * parent=parents->item;
819 struct sort_node * pn = (struct sort_node *) getter(parent);
820 if (pn) {
822 /*
823 * parents are only enqueued for emission
824 * when all their children have been emitted thereby
825 * guaranteeing topological order.
826 */
827 pn->indegree--;
828 if (!pn->indegree) {
829 if (!lifo)
830 insert_by_date(parent, &work);
831 else
832 commit_list_insert(parent, &work);
833 }
834 }
835 parents=parents->next;
836 }
837 /*
838 * work_item is a commit all of whose children
839 * have already been emitted. we can emit it now.
840 */
841 *pptr = work_node->list_item;
842 pptr = &(*pptr)->next;
843 *pptr = NULL;
844 setter(work_item, NULL);
845 }
846 free(nodes);
847}
848/* merge-rebase stuff */
850/* bits #0..7 in revision.h */
852#define PARENT1 (1u<< 8)
853#define PARENT2 (1u<< 9)
854#define STALE (1u<<10)
855static struct commit *interesting(struct commit_list *list)
857{
858 while (list) {
859 struct commit *commit = list->item;
860 list = list->next;
861 if (commit->object.flags & STALE)
862 continue;
863 return commit;
864 }
865 return NULL;
866}
867/*
869 * A pathological example of how this thing works.
870 *
871 * Suppose we had this commit graph, where chronologically
872 * the timestamp on the commit are A <= B <= C <= D <= E <= F
873 * and we are trying to figure out the merge base for E and F
874 * commits.
875 *
876 * F
877 * / \
878 * E A D
879 * \ / /
880 * B /
881 * \ /
882 * C
883 *
884 * First we push E and F to list to be processed. E gets bit 1
885 * and F gets bit 2. The list becomes:
886 *
887 * list=F(2) E(1), result=empty
888 *
889 * Then we pop F, the newest commit, from the list. Its flag is 2.
890 * We scan its parents, mark them reachable from the side that F is
891 * reachable from, and push them to the list:
892 *
893 * list=E(1) D(2) A(2), result=empty
894 *
895 * Next pop E and do the same.
896 *
897 * list=D(2) B(1) A(2), result=empty
898 *
899 * Next pop D and do the same.
900 *
901 * list=C(2) B(1) A(2), result=empty
902 *
903 * Next pop C and do the same.
904 *
905 * list=B(1) A(2), result=empty
906 *
907 * Now it is B's turn. We mark its parent, C, reachable from B's side,
908 * and push it to the list:
909 *
910 * list=C(3) A(2), result=empty
911 *
912 * Now pop C and notice it has flags==3. It is placed on the result list,
913 * and the list now contains:
914 *
915 * list=A(2), result=C(3)
916 *
917 * We pop A and do the same.
918 *
919 * list=B(3), result=C(3)
920 *
921 * Next, we pop B and something very interesting happens. It has flags==3
922 * so it is also placed on the result list, and its parents are marked
923 * stale, retroactively, and placed back on the list:
924 *
925 * list=C(7), result=C(7) B(3)
926 *
927 * Now, list does not have any interesting commit. So we find the newest
928 * commit from the result list that is not marked stale. Which is
929 * commit B.
930 *
931 *
932 * Another pathological example how this thing used to fail to mark an
933 * ancestor of a merge base as STALE before we introduced the
934 * postprocessing phase (mark_reachable_commits).
935 *
936 * 2
937 * H
938 * 1 / \
939 * G A \
940 * |\ / \
941 * | B \
942 * | \ \
943 * \ C F
944 * \ \ /
945 * \ D /
946 * \ | /
947 * \| /
948 * E
949 *
950 * list A B C D E F G H
951 * G1 H2 - - - - - - 1 2
952 * H2 E1 B1 - 1 - - 1 - 1 2
953 * F2 E1 B1 A2 2 1 - - 1 2 1 2
954 * E3 B1 A2 2 1 - - 3 2 1 2
955 * B1 A2 2 1 - - 3 2 1 2
956 * C1 A2 2 1 1 - 3 2 1 2
957 * D1 A2 2 1 1 1 3 2 1 2
958 * A2 2 1 1 1 3 2 1 2
959 * B3 2 3 1 1 3 2 1 2
960 * C7 2 3 7 1 3 2 1 2
961 *
962 * At this point, unfortunately, everybody in the list is
963 * stale, so we fail to complete the following two
964 * steps to fully marking stale commits.
965 *
966 * D7 2 3 7 7 3 2 1 2
967 * E7 2 3 7 7 7 2 1 2
968 *
969 * and we ended up showing E as an interesting merge base.
970 * The postprocessing phase re-injects C and continues traversal
971 * to contaminate D and E.
972 */
973static void mark_reachable_commits(struct commit_list *result,
975 struct commit_list *list)
976{
977 struct commit_list *tmp;
978 /*
980 * Postprocess to fully contaminate the well.
981 */
982 for (tmp = result; tmp; tmp = tmp->next) {
983 struct commit *c = tmp->item;
984 /* Reinject stale ones to list,
985 * so we can scan their parents.
986 */
987 if (c->object.flags & STALE)
988 commit_list_insert(c, &list);
989 }
990 while (list) {
991 struct commit *c = list->item;
992 struct commit_list *parents;
993 tmp = list;
995 list = list->next;
996 free(tmp);
997 /* Anything taken out of the list is stale, so
999 * mark all its parents stale. We do not
1000 * parse new ones (we already parsed all the relevant
1001 * ones).
1002 */
1003 parents = c->parents;
1004 while (parents) {
1005 struct commit *p = parents->item;
1006 parents = parents->next;
1007 if (!(p->object.flags & STALE)) {
1008 p->object.flags |= STALE;
1009 commit_list_insert(p, &list);
1010 }
1011 }
1012 }
1013}
1014struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2,
1016 int cleanup)
1017{
1018 struct commit_list *list = NULL;
1019 struct commit_list *result = NULL;
1020 struct commit_list *tmp = NULL;
1021 if (rev1 == rev2)
1023 return commit_list_insert(rev1, &result);
1024 parse_commit(rev1);
1026 parse_commit(rev2);
1027 rev1->object.flags |= PARENT1;
1029 rev2->object.flags |= PARENT2;
1030 insert_by_date(rev1, &list);
1031 insert_by_date(rev2, &list);
1032 while (interesting(list)) {
1034 struct commit *commit = list->item;
1035 struct commit_list *parents;
1036 int flags = commit->object.flags
1037 & (PARENT1 | PARENT2 | STALE);
1038 tmp = list;
1040 list = list->next;
1041 free(tmp);
1042 if (flags == (PARENT1 | PARENT2)) {
1043 insert_by_date(commit, &result);
1044 /* Mark parents of a found merge stale */
1046 flags |= STALE;
1047 }
1048 parents = commit->parents;
1049 while (parents) {
1050 struct commit *p = parents->item;
1051 parents = parents->next;
1052 if ((p->object.flags & flags) == flags)
1053 continue;
1054 parse_commit(p);
1055 p->object.flags |= flags;
1056 insert_by_date(p, &list);
1057 }
1058 }
1059 if (!result)
1061 return NULL;
1062 if (result->next && list)
1064 mark_reachable_commits(result, list);
1065 /* cull duplicates */
1067 for (tmp = result, list = NULL; tmp; ) {
1068 struct commit *commit = tmp->item;
1069 struct commit_list *next = tmp->next;
1070 if (commit->object.flags & STALE) {
1071 if (list != NULL)
1072 list->next = next;
1073 free(tmp);
1074 } else {
1075 if (list == NULL)
1076 result = tmp;
1077 list = tmp;
1078 commit->object.flags |= STALE;
1079 }
1080 tmp = next;
1082 }
1083 if (cleanup) {
1085 clear_commit_marks(rev1, PARENT1 | PARENT2 | STALE);
1086 clear_commit_marks(rev2, PARENT1 | PARENT2 | STALE);
1087 }
1088 return result;
1090}