When building a fast-import stream, it's easy to forget the fact that
for non-merge commits happening on top of the current branch head, there
is no need for a "from" command. That is corroborated by the fact that
at least git-p4, hg-fast-export and felipec's git-remote-hg all
unconditionally use a "from" command.
Unfortunately, giving a "from" command always resets the branch tree,
forcing it to be re-read, and in many cases, the pack is also closed
and reopened through gfi_unpack_entry. Both are extra unwanted overhead,
and the latter is particularly slow at least on OSX.
So, avoid resetting the tree when it's unmodified, and avoid calling
gfi_unpack_entry when the given mark points to the same commit as the
current branch head.
Signed-off-by: Mike Hommey <mh@xxxxxxxxxxxx>
---
fast-import.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/fast-import.c b/fast-import.c
index e78ca10..372d63a 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -2588,14 +2588,12 @@ static int parse_from(struct branch *b)
{
const char *from;
struct branch *s;
+ unsigned char sha1[20];
if (!skip_prefix(command_buf.buf, "from ", &from))
return 0;
- if (b->branch_tree.tree) {
- release_tree_content_recursive(b->branch_tree.tree);
- b->branch_tree.tree = NULL;
- }
+ hashcpy(sha1, b->branch_tree.versions[1].sha1);
s = lookup_branch(from);
if (b == s)
@@ -2610,14 +2608,16 @@ static int parse_from(struct branch *b)
struct object_entry *oe = find_mark(idnum);
if (oe->type != OBJ_COMMIT)
die("Mark :%" PRIuMAX " not a commit", idnum);
- hashcpy(b->sha1, oe->idx.sha1);
- if (oe->pack_id != MAX_PACK_ID) {
- unsigned long size;
- char *buf = gfi_unpack_entry(oe, &size);
- parse_from_commit(b, buf, size);
- free(buf);
- } else
- parse_from_existing(b);
+ if (hashcmp(b->sha1, oe->idx.sha1)) {
+ hashcpy(b->sha1, oe->idx.sha1);
+ if (oe->pack_id != MAX_PACK_ID) {
+ unsigned long size;
+ char *buf = gfi_unpack_entry(oe, &size);
+ parse_from_commit(b, buf, size);
+ free(buf);
+ } else
+ parse_from_existing(b);
+ }
} else if (!get_sha1(from, b->sha1)) {
parse_from_existing(b);
if (is_null_sha1(b->sha1))
@@ -2626,6 +2626,11 @@ static int parse_from(struct branch *b)
else
die("Invalid ref name or SHA1 expression: %s", from);
+ if (b->branch_tree.tree && hashcmp(sha1, b->branch_tree.versions[1].sha1)) {
+ release_tree_content_recursive(b->branch_tree.tree);
+ b->branch_tree.tree = NULL;
+ }
+
read_next_command();
return 1;
}
--
2.4.3.2.gf0a024e.dirty
--
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