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authorjon@blackcubes.dyndns.org <jon@blackcubes.dyndns.org>2005-06-06 15:39:40 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-06 16:07:26 (GMT)
commita3437b8c26a63d971437c8b6ac6f6d4f632be548 (patch)
tree0e99213a652fbf3fbe2fa6e3d2562808fc776543 /commit.c
parentd925ffbd064802bc8a6ab0bccf0c43b00a7fe710 (diff)
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[PATCH] Modify git-rev-list to linearise the commit history in merge order.
This patch linearises the GIT commit history graph into merge order which is defined by invariants specified in Documentation/git-rev-list.txt. The linearisation produced by this patch is superior in an objective sense to that produced by the existing git-rev-list implementation in that the linearisation produced is guaranteed to have the minimum number of discontinuities, where a discontinuity is defined as an adjacent pair of commits in the output list which are not related in a direct child-parent relationship. With this patch a graph like this: a4 --- | \ \ | b4 | |/ | | a3 | | | | | a2 | | | | c3 | | | | | c2 | b3 | | | /| | b2 | | | c1 | | / | b1 a1 | | | a0 | | / root Sorts like this: = a4 | c3 | c2 | c1 ^ b4 | b3 | b2 | b1 ^ a3 | a2 | a1 | a0 = root Instead of this: = a4 | c3 ^ b4 | a3 ^ c2 ^ b3 ^ a2 ^ b2 ^ c1 ^ a1 ^ b1 ^ a0 = root A test script, t/t6000-rev-list.sh, includes a test which demonstrates that the linearisation produced by --merge-order has less discontinuities than the linearisation produced by git-rev-list without the --merge-order flag specified. To see this, do the following: cd t ./t6000-rev-list.sh cd trash cat actual-default-order cat actual-merge-order The existing behaviour of git-rev-list is preserved, by default. To obtain the modified behaviour, specify --merge-order or --merge-order --show-breaks on the command line. This version of the patch has been tested on the git repository and also on the linux-2.6 repository and has reasonable performance on both - ~50-100% slower than the original algorithm. This version of the patch has incorporated a functional equivalent of the Linus' output limiting algorithm into the merge-order algorithm itself. This operates per the notes associated with Linus' commit 337cb3fb8da45f10fe9a0c3cf571600f55ead2ce. This version has incorporated Linus' feedback regarding proposed changes to rev-list.c. (see: [PATCH] Factor out filtering in rev-list.c) This version has improved the way sort_first_epoch marks commits as uninteresting. For more details about this change, refer to Documentation/git-rev-list.txt and http://blackcubes.dyndns.org/epoch/. Signed-off-by: Jon Seymour <jon.seymour@gmail.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'commit.c')
-rw-r--r--commit.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/commit.c b/commit.c
index 3d3bb1c..21ac2fe 100644
--- a/commit.c
+++ b/commit.c
@@ -130,7 +130,7 @@ void free_commit_list(struct commit_list *list)
}
}
-static void insert_by_date(struct commit_list **list, struct commit *item)
+void insert_by_date(struct commit_list **list, struct commit *item)
{
struct commit_list **pp = list;
struct commit_list *p;
@@ -280,3 +280,25 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
buf[offset] = '\0';
return offset;
}
+
+struct commit *pop_commit(struct commit_list **stack)
+{
+ struct commit_list *top = *stack;
+ struct commit *item = top ? top->item : NULL;
+
+ if (top) {
+ *stack = top->next;
+ free(top);
+ }
+ return item;
+}
+
+int count_parents(struct commit * commit)
+{
+ int count = 0;
+ struct commit_list * parents = commit->parents;
+ for (count=0;parents; parents=parents->next,count++)
+ ;
+ return count;
+}
+