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 commit->object.flags &= ~mark;
401 parents = commit->parents;
402 while (parents) {
403 struct commit *parent = parents->item;
404 /* Have we already cleared this? */
406 if (mark & parent->object.flags)
407 clear_commit_marks(parent, mark);
408 parents = parents->next;
409 }
410}
411/*
413 * Generic support for pretty-printing the header
414 */
415static int get_one_line(const char *msg, unsigned long len)
416{
417 int ret = 0;
418 while (len--) {
420 char c = *msg++;
421 if (!c)
422 break;
423 ret++;
424 if (c == '\n')
425 break;
426 }
427 return ret;
428}
429static int is_rfc2047_special(char ch)
431{
432 return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
433}
434static int add_rfc2047(char *buf, const char *line, int len)
436{
437 char *bp = buf;
438 int i, needquote;
439 static const char q_utf8[] = "=?utf-8?q?";
440 for (i = needquote = 0; !needquote && i < len; i++) {
442 unsigned ch = line[i];
443 if (ch & 0x80)
444 needquote++;
445 if ((i + 1 < len) &&
446 (ch == '=' && line[i+1] == '?'))
447 needquote++;
448 }
449 if (!needquote)
450 return sprintf(buf, "%.*s", len, line);
451 memcpy(bp, q_utf8, sizeof(q_utf8)-1);
453 bp += sizeof(q_utf8)-1;
454 for (i = 0; i < len; i++) {
455 unsigned ch = line[i] & 0xFF;
456 if (is_rfc2047_special(ch)) {
457 sprintf(bp, "=%02X", ch);
458 bp += 3;
459 }
460 else if (ch == ' ')
461 *bp++ = '_';
462 else
463 *bp++ = ch;
464 }
465 memcpy(bp, "?=", 2);
466 bp += 2;
467 return bp - buf;
468}
469static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
471{
472 char *date;
473 int namelen;
474 unsigned long time;
475 int tz, ret;
476 const char *filler = " ";
477 if (fmt == CMIT_FMT_ONELINE)
479 return 0;
480 date = strchr(line, '>');
481 if (!date)
482 return 0;
483 namelen = ++date - line;
484 time = strtoul(date, &date, 10);
485 tz = strtol(date, NULL, 10);
486 if (fmt == CMIT_FMT_EMAIL) {
488 char *name_tail = strchr(line, '<');
489 int display_name_length;
490 if (!name_tail)
491 return 0;
492 while (line < name_tail && isspace(name_tail[-1]))
493 name_tail--;
494 display_name_length = name_tail - line;
495 filler = "";
496 strcpy(buf, "From: ");
497 ret = strlen(buf);
498 ret += add_rfc2047(buf + ret, line, display_name_length);
499 memcpy(buf + ret, name_tail, namelen - display_name_length);
500 ret += namelen - display_name_length;
501 buf[ret++] = '\n';
502 }
503 else {
504 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
505 (fmt == CMIT_FMT_FULLER) ? 4 : 0,
506 filler, namelen, line);
507 }
508 switch (fmt) {
509 case CMIT_FMT_MEDIUM:
510 ret += sprintf(buf + ret, "Date: %s\n", show_date(time, tz));
511 break;
512 case CMIT_FMT_EMAIL:
513 ret += sprintf(buf + ret, "Date: %s\n",
514 show_rfc2822_date(time, tz));
515 break;
516 case CMIT_FMT_FULLER:
517 ret += sprintf(buf + ret, "%sDate: %s\n", what, show_date(time, tz));
518 break;
519 default:
520 /* notin' */
521 break;
522 }
523 return ret;
524}
525static int is_empty_line(const char *line, int *len_p)
527{
528 int len = *len_p;
529 while (len && isspace(line[len-1]))
530 len--;
531 *len_p = len;
532 return !len;
533}
534static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
536{
537 struct commit_list *parent = commit->parents;
538 int offset;
539 if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
541 !parent || !parent->next)
542 return 0;
543 offset = sprintf(buf, "Merge:");
545 while (parent) {
547 struct commit *p = parent->item;
548 const char *hex = abbrev
549 ? find_unique_abbrev(p->object.sha1, abbrev)
550 : sha1_to_hex(p->object.sha1);
551 const char *dots = (abbrev && strlen(hex) != 40) ? "..." : "";
552 parent = parent->next;
553 offset += sprintf(buf + offset, " %s%s", hex, dots);
555 }
556 buf[offset++] = '\n';
557 return offset;
558}
559unsigned 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)
561{
562 int hdr = 1, body = 0;
563 unsigned long offset = 0;
564 int indent = 4;
565 int parents_shown = 0;
566 const char *msg = commit->buffer;
567 int plain_non_ascii = 0;
568 if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
570 indent = 0;
571 /* After-subject is used to pass in Content-Type: multipart
573 * MIME header; in that case we do not have to do the
574 * plaintext content type even if the commit message has
575 * non 7-bit ASCII character. Otherwise, check if we need
576 * to say this is not a 7-bit ASCII.
577 */
578 if (fmt == CMIT_FMT_EMAIL && !after_subject) {
579 int i, ch, in_body;
580 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
582 if (!in_body) {
583 /* author could be non 7-bit ASCII but
584 * the log may so; skip over the
585 * header part first.
586 */
587 if (ch == '\n' &&
588 i + 1 < len && msg[i+1] == '\n')
589 in_body = 1;
590 }
591 else if (ch & 0x80) {
592 plain_non_ascii = 1;
593 break;
594 }
595 }
596 }
597 for (;;) {
599 const char *line = msg;
600 int linelen = get_one_line(msg, len);
601 if (!linelen)
603 break;
604 /*
606 * We want some slop for indentation and a possible
607 * final "...". Thus the "+ 20".
608 */
609 if (offset + linelen + 20 > space) {
610 memcpy(buf + offset, " ...\n", 8);
611 offset += 8;
612 break;
613 }
614 msg += linelen;
616 len -= linelen;
617 if (hdr) {
618 if (linelen == 1) {
619 hdr = 0;
620 if ((fmt != CMIT_FMT_ONELINE) && !subject)
621 buf[offset++] = '\n';
622 continue;
623 }
624 if (fmt == CMIT_FMT_RAW) {
625 memcpy(buf + offset, line, linelen);
626 offset += linelen;
627 continue;
628 }
629 if (!memcmp(line, "parent ", 7)) {
630 if (linelen != 48)
631 die("bad parent line in commit");
632 continue;
633 }
634 if (!parents_shown) {
636 offset += add_merge_info(fmt, buf + offset,
637 commit, abbrev);
638 parents_shown = 1;
639 continue;
640 }
641 /*
642 * MEDIUM == DEFAULT shows only author with dates.
643 * FULL shows both authors but not dates.
644 * FULLER shows both authors and dates.
645 */
646 if (!memcmp(line, "author ", 7))
647 offset += add_user_info("Author", fmt,
648 buf + offset,
649 line + 7);
650 if (!memcmp(line, "committer ", 10) &&
651 (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
652 offset += add_user_info("Commit", fmt,
653 buf + offset,
654 line + 10);
655 continue;
656 }
657 if (is_empty_line(line, &linelen)) {
659 if (!body)
660 continue;
661 if (subject)
662 continue;
663 if (fmt == CMIT_FMT_SHORT)
664 break;
665 } else {
666 body = 1;
667 }
668 if (subject) {
670 int slen = strlen(subject);
671 memcpy(buf + offset, subject, slen);
672 offset += slen;
673 offset += add_rfc2047(buf + offset, line, linelen);
674 }
675 else {
676 memset(buf + offset, ' ', indent);
677 memcpy(buf + offset + indent, line, linelen);
678 offset += linelen + indent;
679 }
680 buf[offset++] = '\n';
681 if (fmt == CMIT_FMT_ONELINE)
682 break;
683 if (subject && plain_non_ascii) {
684 static const char header[] =
685 "Content-Type: text/plain; charset=UTF-8\n"
686 "Content-Transfer-Encoding: 8bit\n";
687 memcpy(buf + offset, header, sizeof(header)-1);
688 offset += sizeof(header)-1;
689 }
690 if (after_subject) {
691 int slen = strlen(after_subject);
692 if (slen > space - offset - 1)
693 slen = space - offset - 1;
694 memcpy(buf + offset, after_subject, slen);
695 offset += slen;
696 after_subject = NULL;
697 }
698 subject = NULL;
699 }
700 while (offset && isspace(buf[offset-1]))
701 offset--;
702 /* Make sure there is an EOLN for the non-oneline case */
703 if (fmt != CMIT_FMT_ONELINE)
704 buf[offset++] = '\n';
705 buf[offset] = '\0';
706 return offset;
707}
708struct commit *pop_commit(struct commit_list **stack)
710{
711 struct commit_list *top = *stack;
712 struct commit *item = top ? top->item : NULL;
713 if (top) {
715 *stack = top->next;
716 free(top);
717 }
718 return item;
719}
720int count_parents(struct commit * commit)
722{
723 int count = 0;
724 struct commit_list * parents = commit->parents;
725 for (count=0;parents; parents=parents->next,count++)
726 ;
727 return count;
728}
729void topo_sort_default_setter(struct commit *c, void *data)
731{
732 c->util = data;
733}
734void *topo_sort_default_getter(struct commit *c)
736{
737 return c->util;
738}
739/*
741 * Performs an in-place topological sort on the list supplied.
742 */
743void sort_in_topological_order(struct commit_list ** list, int lifo)
744{
745 sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
746 topo_sort_default_getter);
747}
748void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
750 topo_sort_set_fn_t setter,
751 topo_sort_get_fn_t getter)
752{
753 struct commit_list * next = *list;
754 struct commit_list * work = NULL, **insert;
755 struct commit_list ** pptr = list;
756 struct sort_node * nodes;
757 struct sort_node * next_nodes;
758 int count = 0;
759 /* determine the size of the list */
761 while (next) {
762 next = next->next;
763 count++;
764 }
765
766 if (!count)
767 return;
768 /* allocate an array to help sort the list */
769 nodes = xcalloc(count, sizeof(*nodes));
770 /* link the list to the array */
771 next_nodes = nodes;
772 next=*list;
773 while (next) {
774 next_nodes->list_item = next;
775 setter(next->item, next_nodes);
776 next_nodes++;
777 next = next->next;
778 }
779 /* update the indegree */
780 next=*list;
781 while (next) {
782 struct commit_list * parents = next->item->parents;
783 while (parents) {
784 struct commit * parent=parents->item;
785 struct sort_node * pn = (struct sort_node *) getter(parent);
786 if (pn)
788 pn->indegree++;
789 parents=parents->next;
790 }
791 next=next->next;
792 }
793 /*
794 * find the tips
795 *
796 * tips are nodes not reachable from any other node in the list
797 *
798 * the tips serve as a starting set for the work queue.
799 */
800 next=*list;
801 insert = &work;
802 while (next) {
803 struct sort_node * node = (struct sort_node *) getter(next->item);
804 if (node->indegree == 0) {
806 insert = &commit_list_insert(next->item, insert)->next;
807 }
808 next=next->next;
809 }
810 /* process the list in topological order */
812 if (!lifo)
813 sort_by_date(&work);
814 while (work) {
815 struct commit * work_item = pop_commit(&work);
816 struct sort_node * work_node = (struct sort_node *) getter(work_item);
817 struct commit_list * parents = work_item->parents;
818 while (parents) {
820 struct commit * parent=parents->item;
821 struct sort_node * pn = (struct sort_node *) getter(parent);
822 if (pn) {
824 /*
825 * parents are only enqueued for emission
826 * when all their children have been emitted thereby
827 * guaranteeing topological order.
828 */
829 pn->indegree--;
830 if (!pn->indegree) {
831 if (!lifo)
832 insert_by_date(parent, &work);
833 else
834 commit_list_insert(parent, &work);
835 }
836 }
837 parents=parents->next;
838 }
839 /*
840 * work_item is a commit all of whose children
841 * have already been emitted. we can emit it now.
842 */
843 *pptr = work_node->list_item;
844 pptr = &(*pptr)->next;
845 *pptr = NULL;
846 setter(work_item, NULL);
847 }
848 free(nodes);
849}
850/* merge-rebase stuff */
852/* bits #0..7 in revision.h */
854#define PARENT1 (1u<< 8)
855#define PARENT2 (1u<< 9)
856#define STALE (1u<<10)
857static struct commit *interesting(struct commit_list *list)
859{
860 while (list) {
861 struct commit *commit = list->item;
862 list = list->next;
863 if (commit->object.flags & STALE)
864 continue;
865 return commit;
866 }
867 return NULL;
868}
869/*
871 * A pathological example of how this thing works.
872 *
873 * Suppose we had this commit graph, where chronologically
874 * the timestamp on the commit are A <= B <= C <= D <= E <= F
875 * and we are trying to figure out the merge base for E and F
876 * commits.
877 *
878 * F
879 * / \
880 * E A D
881 * \ / /
882 * B /
883 * \ /
884 * C
885 *
886 * First we push E and F to list to be processed. E gets bit 1
887 * and F gets bit 2. The list becomes:
888 *
889 * list=F(2) E(1), result=empty
890 *
891 * Then we pop F, the newest commit, from the list. Its flag is 2.
892 * We scan its parents, mark them reachable from the side that F is
893 * reachable from, and push them to the list:
894 *
895 * list=E(1) D(2) A(2), result=empty
896 *
897 * Next pop E and do the same.
898 *
899 * list=D(2) B(1) A(2), result=empty
900 *
901 * Next pop D and do the same.
902 *
903 * list=C(2) B(1) A(2), result=empty
904 *
905 * Next pop C and do the same.
906 *
907 * list=B(1) A(2), result=empty
908 *
909 * Now it is B's turn. We mark its parent, C, reachable from B's side,
910 * and push it to the list:
911 *
912 * list=C(3) A(2), result=empty
913 *
914 * Now pop C and notice it has flags==3. It is placed on the result list,
915 * and the list now contains:
916 *
917 * list=A(2), result=C(3)
918 *
919 * We pop A and do the same.
920 *
921 * list=B(3), result=C(3)
922 *
923 * Next, we pop B and something very interesting happens. It has flags==3
924 * so it is also placed on the result list, and its parents are marked
925 * stale, retroactively, and placed back on the list:
926 *
927 * list=C(7), result=C(7) B(3)
928 *
929 * Now, list does not have any interesting commit. So we find the newest
930 * commit from the result list that is not marked stale. Which is
931 * commit B.
932 *
933 *
934 * Another pathological example how this thing used to fail to mark an
935 * ancestor of a merge base as STALE before we introduced the
936 * postprocessing phase (mark_reachable_commits).
937 *
938 * 2
939 * H
940 * 1 / \
941 * G A \
942 * |\ / \
943 * | B \
944 * | \ \
945 * \ C F
946 * \ \ /
947 * \ D /
948 * \ | /
949 * \| /
950 * E
951 *
952 * list A B C D E F G H
953 * G1 H2 - - - - - - 1 2
954 * H2 E1 B1 - 1 - - 1 - 1 2
955 * F2 E1 B1 A2 2 1 - - 1 2 1 2
956 * E3 B1 A2 2 1 - - 3 2 1 2
957 * B1 A2 2 1 - - 3 2 1 2
958 * C1 A2 2 1 1 - 3 2 1 2
959 * D1 A2 2 1 1 1 3 2 1 2
960 * A2 2 1 1 1 3 2 1 2
961 * B3 2 3 1 1 3 2 1 2
962 * C7 2 3 7 1 3 2 1 2
963 *
964 * At this point, unfortunately, everybody in the list is
965 * stale, so we fail to complete the following two
966 * steps to fully marking stale commits.
967 *
968 * D7 2 3 7 7 3 2 1 2
969 * E7 2 3 7 7 7 2 1 2
970 *
971 * and we ended up showing E as an interesting merge base.
972 * The postprocessing phase re-injects C and continues traversal
973 * to contaminate D and E.
974 */
975static void mark_reachable_commits(struct commit_list *result,
977 struct commit_list *list)
978{
979 struct commit_list *tmp;
980 /*
982 * Postprocess to fully contaminate the well.
983 */
984 for (tmp = result; tmp; tmp = tmp->next) {
985 struct commit *c = tmp->item;
986 /* Reinject stale ones to list,
987 * so we can scan their parents.
988 */
989 if (c->object.flags & STALE)
990 commit_list_insert(c, &list);
991 }
992 while (list) {
993 struct commit *c = list->item;
994 struct commit_list *parents;
995 tmp = list;
997 list = list->next;
998 free(tmp);
999 /* Anything taken out of the list is stale, so
1001 * mark all its parents stale. We do not
1002 * parse new ones (we already parsed all the relevant
1003 * ones).
1004 */
1005 parents = c->parents;
1006 while (parents) {
1007 struct commit *p = parents->item;
1008 parents = parents->next;
1009 if (!(p->object.flags & STALE)) {
1010 p->object.flags |= STALE;
1011 commit_list_insert(p, &list);
1012 }
1013 }
1014 }
1015}
1016struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2,
1018 int cleanup)
1019{
1020 struct commit_list *list = NULL;
1021 struct commit_list *result = NULL;
1022 struct commit_list *tmp = NULL;
1023 if (rev1 == rev2)
1025 return commit_list_insert(rev1, &result);
1026 parse_commit(rev1);
1028 parse_commit(rev2);
1029 rev1->object.flags |= PARENT1;
1031 rev2->object.flags |= PARENT2;
1032 insert_by_date(rev1, &list);
1033 insert_by_date(rev2, &list);
1034 while (interesting(list)) {
1036 struct commit *commit = list->item;
1037 struct commit_list *parents;
1038 int flags = commit->object.flags
1039 & (PARENT1 | PARENT2 | STALE);
1040 tmp = list;
1042 list = list->next;
1043 free(tmp);
1044 if (flags == (PARENT1 | PARENT2)) {
1045 insert_by_date(commit, &result);
1046 /* Mark parents of a found merge stale */
1048 flags |= STALE;
1049 }
1050 parents = commit->parents;
1051 while (parents) {
1052 struct commit *p = parents->item;
1053 parents = parents->next;
1054 if ((p->object.flags & flags) == flags)
1055 continue;
1056 parse_commit(p);
1057 p->object.flags |= flags;
1058 insert_by_date(p, &list);
1059 }
1060 }
1061 if (!result)
1063 goto finish;
1064 if (result->next && list)
1066 mark_reachable_commits(result, list);
1067 /* cull duplicates */
1069 for (tmp = result, list = NULL; tmp; ) {
1070 struct commit *commit = tmp->item;
1071 struct commit_list *next = tmp->next;
1072 if (commit->object.flags & STALE) {
1073 if (list != NULL)
1074 list->next = next;
1075 free(tmp);
1076 } else {
1077 if (list == NULL)
1078 result = tmp;
1079 list = tmp;
1080 commit->object.flags |= STALE;
1081 }
1082 tmp = next;
1084 }
1085 finish:
1087 if (cleanup) {
1088 clear_commit_marks(rev1, PARENT1 | PARENT2 | STALE);
1089 clear_commit_marks(rev2, PARENT1 | PARENT2 | STALE);
1090 }
1091 return result;
1093}