Re: [PATCH] fetch-pack should not ask for a ref which is already there
Hi,
On Thu, 29 Sep 2005, Linus Torvalds wrote:
Show 6 quoted lines
> On Thu, 29 Sep 2005, Johannes Schindelin wrote:
> >
> > With this patch, instead of blindly asking for every remote ref, fetch-pack
> > first looks in the local repository if that ref is already there.
>
> No. This is WRONG.
Actually, this is not wrong. The patch is wrong. Here's why:
> The "fetch" semantics are simple: we only write out new refs _after_ we've
> fetched all the objects that point to them. That means that while we
> cannot trust a "oh, I already have this commit, let's skip it", we _can_
> trust "oh, I already have these refs, let's skip them".
What the commit message should suggest was: if a local ref is identical to the remote ref, do not "want" it. But of course, I got it all wrong. BTW this patch is not to annoy you, but to ease the burden on the server for git-daemon. (Many a developer begins the day by fetching the latest and greatest).
The correct way to go about it would be to check that
$(git-rev-list <remote_ref> $(git-rev-parse --all | sed "s/^/^/"))
is empty. However, I am lazy, and in most cases, it is sufficient to check if the remote ref is identical to a local ref. So here goes another try:
[PATCH] fetch-pack should not ask for a ref which is already there
With this patch, instead of blindly asking for every remote ref, fetch-pack first looks in the local repository if that ref is already a local ref.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
---
fetch-pack.c | 72 ++++++++++++++++++++++++++++++++++++++++++----------------
1 files changed, 52 insertions(+), 20 deletions(-)
edfbae3927434270c35dfcad417e7d202e509e90
Show changes to fetch-pack.c +52 −20
diff --git a/fetch-pack.c b/fetch-pack.c
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -9,6 +9,22 @@ static const char fetch_pack_usage[] =
"git-fetch-pack [-q] [-v] [--exec=upload-pack] [host:]directory <refs>...";
static const char *exec = "git-upload-pack";
+static int has_ref_flag;
+static const unsigned char *has_ref_sha1;
+
+static int has_ref_helper(const char *path, const unsigned char *sha1) {
+ if(!memcmp(sha1, has_ref_sha1, 20))
+ has_ref_flag = 1;
+ return has_ref_flag;
+}
+
+static int has_ref(const unsigned char *sha1) {
+ has_ref_sha1 = sha1;
+ has_ref_flag = 0;
+ for_each_ref(has_ref_helper);
+ return has_ref_flag;
+}
+
static int find_common(int fd[2], unsigned char *result_sha1,
struct ref *refs)
{
@@ -16,20 +32,27 @@ static int find_common(int fd[2], unsign
int count = 0, flushes = 0, retval;
FILE *revs;
- revs = popen("git-rev-list $(git-rev-parse --all)", "r");
- if (!revs)
- die("unable to run 'git-rev-list'");
-
while (refs) {
unsigned char *remote = refs->old_sha1;
- if (verbose)
- fprintf(stderr,
- "want %s (%s)\n", sha1_to_hex(remote),
- refs->name);
- packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
+ if(!has_ref(remote)) {
+ if (verbose)
+ fprintf(stderr,
+ "want %s (%s)\n", sha1_to_hex(remote),
+ refs->name);
+ packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
+ count++;
+ }
refs = refs->next;
}
packet_flush(fd[1]);
+
+ if(count==0)
+ return 1;
+
+ revs = popen("git-rev-list $(git-rev-parse --all)", "r");
+ if (!revs)
+ die("unable to run 'git-rev-list'");
+
flushes = 1;
retval = -1;
while (fgets(line, sizeof(line), revs) != NULL) {
@@ -74,7 +97,7 @@ static int find_common(int fd[2], unsign
return retval;
}
-static int fetch_pack(int fd[2], int nr_match, char **match)
+static struct ref *fetch_pack(int fd[2], int nr_match, char **match)
{
struct ref *ref;
unsigned char sha1[20];
@@ -86,7 +109,10 @@ static int fetch_pack(int fd[2], int nr_
packet_flush(fd[1]);
die("no matching remote head");
}
- if (find_common(fd, sha1, ref) < 0)
+ status = find_common(fd, sha1, ref);
+ if(status > 0)
+ return ref;
+ if(status < 0)
fprintf(stderr, "warning: no common commits\n");
pid = fork();
if (pid < 0)
@@ -109,12 +135,7 @@ static int fetch_pack(int fd[2], int nr_
int code = WEXITSTATUS(status);
if (code)
die("git-unpack-objects died with error code %d", code);
- while (ref) {
- printf("%s %s\n",
- sha1_to_hex(ref->old_sha1), ref->name);
- ref = ref->next;
- }
- return 0;
+ return ref;
}
if (WIFSIGNALED(status)) {
int sig = WTERMSIG(status);
@@ -125,10 +146,11 @@ static int fetch_pack(int fd[2], int nr_
int main(int argc, char **argv)
{
- int i, ret, nr_heads;
+ int i, nr_heads;
char *dest = NULL, **heads;
int fd[2];
pid_t pid;
+ struct ref *ref;
nr_heads = 0;
heads = NULL;
@@ -160,9 +182,19 @@ int main(int argc, char **argv)
pid = git_connect(fd, dest, exec);
if (pid < 0)
return 1;
- ret = fetch_pack(fd, nr_heads, heads);
+ ref = fetch_pack(fd, nr_heads, heads);
+ if(!ref)
+ return 1;
+
+ while (ref) {
+ printf("%s %s\n",
+ sha1_to_hex(ref->old_sha1), ref->name);
+ ref = ref->next;
+ }
+
close(fd[0]);
close(fd[1]);
finish_connect(pid);
- return ret;
+
+ return 0;
}
Johannes Schindelin
