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Merge branch 'js/merge-base'

This commit is contained in:
Junio C Hamano 2006-07-06 19:26:13 -07:00
parent c31cfb3db3 b7d936b2fd
commit bf928e9d2c
6 changed files with 354 additions and 243 deletions
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14
Documentation/git-rev-list.txt
View File

@ -15,6 +15,7 @@ SYNOPSIS
[ \--sparse ]
[ \--no-merges ]
[ \--remove-empty ]
[ \--not ]
[ \--all ]
[ \--topo-order ]
[ \--parents ]
@ -37,6 +38,14 @@ not in 'baz'".
A special notation <commit1>..<commit2> can be used as a
short-hand for {caret}<commit1> <commit2>.
Another special notation is <commit1>...<commit2> which is useful for
merges. The resulting set of commits is the symmetric difference
between the two operands. The following two commands are equivalent:
------------
$ git-rev-list A B --not $(git-merge-base --all A B)
$ git-rev-list A...B
------------
OPTIONS
-------
@ -93,6 +102,11 @@ OPTIONS
--remove-empty::
Stop when a given path disappears from the tree.
--not::
Reverses the meaning of the '{caret}' prefix (or lack
thereof) for all following revision specifiers, up to
the next `--not`.
--all::
Pretend as if all the refs in `$GIT_DIR/refs/` are
listed on the command line as <commit>.

65
builtin-rev-parse.c
View File

@ -164,6 +164,51 @@ static int show_file(const char *arg)
return 0;
}
static int try_difference(const char *arg)
{
char *dotdot;
unsigned char sha1[20];
unsigned char end[20];
const char *next;
const char *this;
int symmetric;
if (!(dotdot = strstr(arg, "..")))
return 0;
next = dotdot + 2;
this = arg;
symmetric = (*next == '.');
*dotdot = 0;
next += symmetric;
if (!*next)
next = "HEAD";
if (dotdot == arg)
this = "HEAD";
if (!get_sha1(this, sha1) && !get_sha1(next, end)) {
show_rev(NORMAL, end, next);
show_rev(symmetric ? NORMAL : REVERSED, sha1, this);
if (symmetric) {
struct commit_list *exclude;
struct commit *a, *b;
a = lookup_commit_reference(sha1);
b = lookup_commit_reference(end);
exclude = get_merge_bases(a, b, 1);
while (exclude) {
struct commit_list *n = exclude->next;
show_rev(REVERSED,
exclude->item->object.sha1,NULL);
free(exclude);
exclude = n;
}
}
return 1;
}
*dotdot = '.';
return 0;
}
int cmd_rev_parse(int argc, const char **argv, char **envp)
{
int i, as_is = 0, verify = 0;
@ -174,7 +219,6 @@ int cmd_rev_parse(int argc, const char **argv, char **envp)
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
char *dotdot;
if (as_is) {
if (show_file(arg) && as_is < 2)
@ -326,23 +370,8 @@ int cmd_rev_parse(int argc, const char **argv, char **envp)
}
/* Not a flag argument */
dotdot = strstr(arg, "..");
if (dotdot) {
unsigned char end[20];
const char *next = dotdot + 2;
const char *this = arg;
*dotdot = 0;
if (!*next)
next = "HEAD";
if (dotdot == arg)
this = "HEAD";
if (!get_sha1(this, sha1) && !get_sha1(next, end)) {
show_rev(NORMAL, end, next);
show_rev(REVERSED, sha1, this);
continue;
}
*dotdot = '.';
}
if (try_difference(arg))
continue;
if (!get_sha1(arg, sha1)) {
show_rev(NORMAL, sha1, arg);
continue;

251
commit.c
View File

@ -397,12 +397,13 @@ void clear_commit_marks(struct commit *commit, unsigned int mark)
{
struct commit_list *parents;
parents = commit->parents;
commit->object.flags &= ~mark;
parents = commit->parents;
while (parents) {
struct commit *parent = parents->item;
if (parent && parent->object.parsed &&
(parent->object.flags & mark))
/* Have we already cleared this? */
if (mark & parent->object.flags)
clear_commit_marks(parent, mark);
parents = parents->next;
}
@ -846,3 +847,247 @@ void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
}
free(nodes);
}
/* merge-rebase stuff */
/* bits #0..7 in revision.h */
#define PARENT1 (1u<< 8)
#define PARENT2 (1u<< 9)
#define STALE (1u<<10)
static struct commit *interesting(struct commit_list *list)
{
while (list) {
struct commit *commit = list->item;
list = list->next;
if (commit->object.flags & STALE)
continue;
return commit;
}
return NULL;
}
/*
* A pathological example of how this thing works.
*
* Suppose we had this commit graph, where chronologically
* the timestamp on the commit are A <= B <= C <= D <= E <= F
* and we are trying to figure out the merge base for E and F
* commits.
*
* F
* / \
* E A D
* \ / /
* B /
* \ /
* C
*
* First we push E and F to list to be processed. E gets bit 1
* and F gets bit 2. The list becomes:
*
* list=F(2) E(1), result=empty
*
* Then we pop F, the newest commit, from the list. Its flag is 2.
* We scan its parents, mark them reachable from the side that F is
* reachable from, and push them to the list:
*
* list=E(1) D(2) A(2), result=empty
*
* Next pop E and do the same.
*
* list=D(2) B(1) A(2), result=empty
*
* Next pop D and do the same.
*
* list=C(2) B(1) A(2), result=empty
*
* Next pop C and do the same.
*
* list=B(1) A(2), result=empty
*
* Now it is B's turn. We mark its parent, C, reachable from B's side,
* and push it to the list:
*
* list=C(3) A(2), result=empty
*
* Now pop C and notice it has flags==3. It is placed on the result list,
* and the list now contains:
*
* list=A(2), result=C(3)
*
* We pop A and do the same.
*
* list=B(3), result=C(3)
*
* Next, we pop B and something very interesting happens. It has flags==3
* so it is also placed on the result list, and its parents are marked
* stale, retroactively, and placed back on the list:
*
* list=C(7), result=C(7) B(3)
*
* Now, list does not have any interesting commit. So we find the newest
* commit from the result list that is not marked stale. Which is
* commit B.
*
*
* Another pathological example how this thing used to fail to mark an
* ancestor of a merge base as STALE before we introduced the
* postprocessing phase (mark_reachable_commits).
*
* 2
* H
* 1 / \
* G A \
* |\ / \
* | B \
* | \ \
* \ C F
* \ \ /
* \ D /
* \ | /
* \| /
* E
*
* list A B C D E F G H
* G1 H2 - - - - - - 1 2
* H2 E1 B1 - 1 - - 1 - 1 2
* F2 E1 B1 A2 2 1 - - 1 2 1 2
* E3 B1 A2 2 1 - - 3 2 1 2
* B1 A2 2 1 - - 3 2 1 2
* C1 A2 2 1 1 - 3 2 1 2
* D1 A2 2 1 1 1 3 2 1 2
* A2 2 1 1 1 3 2 1 2
* B3 2 3 1 1 3 2 1 2
* C7 2 3 7 1 3 2 1 2
*
* At this point, unfortunately, everybody in the list is
* stale, so we fail to complete the following two
* steps to fully marking stale commits.
*
* D7 2 3 7 7 3 2 1 2
* E7 2 3 7 7 7 2 1 2
*
* and we ended up showing E as an interesting merge base.
* The postprocessing phase re-injects C and continues traversal
* to contaminate D and E.
*/
static void mark_reachable_commits(struct commit_list *result,
struct commit_list *list)
{
struct commit_list *tmp;
/*
* Postprocess to fully contaminate the well.
*/
for (tmp = result; tmp; tmp = tmp->next) {
struct commit *c = tmp->item;
/* Reinject stale ones to list,
* so we can scan their parents.
*/
if (c->object.flags & STALE)
commit_list_insert(c, &list);
}
while (list) {
struct commit *c = list->item;
struct commit_list *parents;
tmp = list;
list = list->next;
free(tmp);
/* Anything taken out of the list is stale, so
* mark all its parents stale. We do not
* parse new ones (we already parsed all the relevant
* ones).
*/
parents = c->parents;
while (parents) {
struct commit *p = parents->item;
parents = parents->next;
if (!(p->object.flags & STALE)) {
p->object.flags |= STALE;
commit_list_insert(p, &list);
}
}
}
}
struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2,
int cleanup)
{
struct commit_list *list = NULL;
struct commit_list *result = NULL;
struct commit_list *tmp = NULL;
if (rev1 == rev2)
return commit_list_insert(rev1, &result);
parse_commit(rev1);
parse_commit(rev2);
rev1->object.flags |= PARENT1;
rev2->object.flags |= PARENT2;
insert_by_date(rev1, &list);
insert_by_date(rev2, &list);
while (interesting(list)) {
struct commit *commit = list->item;
struct commit_list *parents;
int flags = commit->object.flags
& (PARENT1 | PARENT2 | STALE);
tmp = list;
list = list->next;
free(tmp);
if (flags == (PARENT1 | PARENT2)) {
insert_by_date(commit, &result);
/* Mark parents of a found merge stale */
flags |= STALE;
}
parents = commit->parents;
while (parents) {
struct commit *p = parents->item;
parents = parents->next;
if ((p->object.flags & flags) == flags)
continue;
parse_commit(p);
p->object.flags |= flags;
insert_by_date(p, &list);
}
}
if (!result)
goto finish;
if (result->next && list)
mark_reachable_commits(result, list);
/* cull duplicates */
for (tmp = result, list = NULL; tmp; ) {
struct commit *commit = tmp->item;
struct commit_list *next = tmp->next;
if (commit->object.flags & STALE) {
if (list != NULL)
list->next = next;
free(tmp);
} else {
if (list == NULL)
result = tmp;
list = tmp;
commit->object.flags |= STALE;
}
tmp = next;
}
finish:
if (cleanup) {
clear_commit_marks(rev1, PARENT1 | PARENT2 | STALE);
clear_commit_marks(rev2, PARENT1 | PARENT2 | STALE);
}
return result;
}

2
commit.h
View File

@ -105,4 +105,6 @@ struct commit_graft *read_graft_line(char *buf, int len);
int register_commit_graft(struct commit_graft *, int);
int read_graft_file(const char *graft_file);
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
#endif /* COMMIT_H */

218
merge-base.c
View File

@ -2,232 +2,22 @@
#include "cache.h"
#include "commit.h"
#define PARENT1 1
#define PARENT2 2
#define UNINTERESTING 4
static struct commit *interesting(struct commit_list *list)
{
while (list) {
struct commit *commit = list->item;
list = list->next;
if (commit->object.flags & UNINTERESTING)
continue;
return commit;
}
return NULL;
}
/*
* A pathological example of how this thing works.
*
* Suppose we had this commit graph, where chronologically
* the timestamp on the commit are A <= B <= C <= D <= E <= F
* and we are trying to figure out the merge base for E and F
* commits.
*
* F
* / \
* E A D
* \ / /
* B /
* \ /
* C
*
* First we push E and F to list to be processed. E gets bit 1
* and F gets bit 2. The list becomes:
*
* list=F(2) E(1), result=empty
*
* Then we pop F, the newest commit, from the list. Its flag is 2.
* We scan its parents, mark them reachable from the side that F is
* reachable from, and push them to the list:
*
* list=E(1) D(2) A(2), result=empty
*
* Next pop E and do the same.
*
* list=D(2) B(1) A(2), result=empty
*
* Next pop D and do the same.
*
* list=C(2) B(1) A(2), result=empty
*
* Next pop C and do the same.
*
* list=B(1) A(2), result=empty
*
* Now it is B's turn. We mark its parent, C, reachable from B's side,
* and push it to the list:
*
* list=C(3) A(2), result=empty
*
* Now pop C and notice it has flags==3. It is placed on the result list,
* and the list now contains:
*
* list=A(2), result=C(3)
*
* We pop A and do the same.
*
* list=B(3), result=C(3)
*
* Next, we pop B and something very interesting happens. It has flags==3
* so it is also placed on the result list, and its parents are marked
* uninteresting, retroactively, and placed back on the list:
*
* list=C(7), result=C(7) B(3)
*
* Now, list does not have any interesting commit. So we find the newest
* commit from the result list that is not marked uninteresting. Which is
* commit B.
*
*
* Another pathological example how this thing used to fail to mark an
* ancestor of a merge base as UNINTERESTING before we introduced the
* postprocessing phase (mark_reachable_commits).
*
* 2
* H
* 1 / \
* G A \
* |\ / \
* | B \
* | \ \
* \ C F
* \ \ /
* \ D /
* \ | /
* \| /
* E
*
* list A B C D E F G H
* G1 H2 - - - - - - 1 2
* H2 E1 B1 - 1 - - 1 - 1 2
* F2 E1 B1 A2 2 1 - - 1 2 1 2
* E3 B1 A2 2 1 - - 3 2 1 2
* B1 A2 2 1 - - 3 2 1 2
* C1 A2 2 1 1 - 3 2 1 2
* D1 A2 2 1 1 1 3 2 1 2
* A2 2 1 1 1 3 2 1 2
* B3 2 3 1 1 3 2 1 2
* C7 2 3 7 1 3 2 1 2
*
* At this point, unfortunately, everybody in the list is
* uninteresting, so we fail to complete the following two
* steps to fully marking uninteresting commits.
*
* D7 2 3 7 7 3 2 1 2
* E7 2 3 7 7 7 2 1 2
*
* and we ended up showing E as an interesting merge base.
* The postprocessing phase re-injects C and continues traversal
* to contaminate D and E.
*/
static int show_all = 0;
static void mark_reachable_commits(struct commit_list *result,
struct commit_list *list)
{
struct commit_list *tmp;
/*
* Postprocess to fully contaminate the well.
*/
for (tmp = result; tmp; tmp = tmp->next) {
struct commit *c = tmp->item;
/* Reinject uninteresting ones to list,
* so we can scan their parents.
*/
if (c->object.flags & UNINTERESTING)
commit_list_insert(c, &list);
}
while (list) {
struct commit *c = list->item;
struct commit_list *parents;
tmp = list;
list = list->next;
free(tmp);
/* Anything taken out of the list is uninteresting, so
* mark all its parents uninteresting. We do not
* parse new ones (we already parsed all the relevant
* ones).
*/
parents = c->parents;
while (parents) {
struct commit *p = parents->item;
parents = parents->next;
if (!(p->object.flags & UNINTERESTING)) {
p->object.flags |= UNINTERESTING;
commit_list_insert(p, &list);
}
}
}
}
static int merge_base(struct commit *rev1, struct commit *rev2)
{
struct commit_list *list = NULL;
struct commit_list *result = NULL;
struct commit_list *tmp = NULL;
if (rev1 == rev2) {
printf("%s\n", sha1_to_hex(rev1->object.sha1));
return 0;
}
parse_commit(rev1);
parse_commit(rev2);
rev1->object.flags |= 1;
rev2->object.flags |= 2;
insert_by_date(rev1, &list);
insert_by_date(rev2, &list);
while (interesting(list)) {
struct commit *commit = list->item;
struct commit_list *parents;
int flags = commit->object.flags & 7;
tmp = list;
list = list->next;
free(tmp);
if (flags == 3) {
insert_by_date(commit, &result);
/* Mark parents of a found merge uninteresting */
flags |= UNINTERESTING;
}
parents = commit->parents;
while (parents) {
struct commit *p = parents->item;
parents = parents->next;
if ((p->object.flags & flags) == flags)
continue;
parse_commit(p);
p->object.flags |= flags;
insert_by_date(p, &list);
}
}
struct commit_list *result = get_merge_bases(rev1, rev2, 0);
if (!result)
return 1;
if (result->next && list)
mark_reachable_commits(result, list);
while (result) {
struct commit *commit = result->item;
result = result->next;
if (commit->object.flags & UNINTERESTING)
continue;
printf("%s\n", sha1_to_hex(commit->object.sha1));
printf("%s\n", sha1_to_hex(result->item->object.sha1));
if (!show_all)
return 0;
commit->object.flags |= UNINTERESTING;
result = result->next;
}
return 0;
}

47
revision.c
View File

@ -537,6 +537,18 @@ void init_revisions(struct rev_info *revs)
diff_setup(&revs->diffopt);
}
static void add_pending_commit_list(struct rev_info *revs,
struct commit_list *commit_list,
unsigned int flags)
{
while (commit_list) {
struct object *object = &commit_list->item->object;
object->flags |= flags;
add_pending_object(revs, object, sha1_to_hex(object->sha1));
commit_list = commit_list->next;
}
}
/*
* Parse revision information, filling in the "rev_info" structure,
* and removing the used arguments from the argument list.
@ -772,27 +784,46 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
unsigned char from_sha1[20];
const char *next = dotdot + 2;
const char *this = arg;
int symmetric = *next == '.';
unsigned int flags_exclude = flags ^ UNINTERESTING;
*dotdot = 0;
next += symmetric;
if (!*next)
next = "HEAD";
if (dotdot == arg)
this = "HEAD";
if (!get_sha1(this, from_sha1) &&
!get_sha1(next, sha1)) {
struct object *exclude;
struct object *include;
struct commit *a, *b;
struct commit_list *exclude;
exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
include = get_reference(revs, next, sha1, flags);
if (!exclude || !include)
die("Invalid revision range %s..%s", arg, next);
a = lookup_commit_reference(from_sha1);
b = lookup_commit_reference(sha1);
if (!a || !b) {
die(symmetric ?
"Invalid symmetric difference expression %s...%s" :
"Invalid revision range %s..%s",
arg, next);
}
if (!seen_dashdash) {
*dotdot = '.';
verify_non_filename(revs->prefix, arg);
}
add_pending_object(revs, exclude, this);
add_pending_object(revs, include, next);
if (symmetric) {
exclude = get_merge_bases(a, b, 1);
add_pending_commit_list(revs, exclude,
flags_exclude);
free_commit_list(exclude);
a->object.flags |= flags;
} else
a->object.flags |= flags_exclude;
b->object.flags |= flags;
add_pending_object(revs, &a->object, this);
add_pending_object(revs, &b->object, next);
continue;
}
*dotdot = '.';