Re: expensive local git clone

[Junio C Hamano <junkio@cox.net>]

>>>>> "DSM" == David S Miller <davem@davemloft.net> writes:

DSM> I keep hoping git-clone-script is going to be a good way
DSM> to clone two local trees.  Is my hope misguided?  :-)

Something along these lines?
------------
Short-cut "git fetch" when cloning locally.

Instead of calling local-pull to "do the right thing", just
hardlink or copy the object files over when we know we are doing
the clone locally.

Signed-off-by: Junio C Hamano <junkio@cox.net>
---

cd /opt/packrat/playpen/public/in-place/git/git.junio/
jit-diff
# - master: git-format-patch: Prepare patches for e-mail submission.
# + (working tree)
diff --git a/git-clone-script b/git-clone-script
--- a/git-clone-script
+++ b/git-clone-script
@@ -1,7 +1,39 @@
 #!/bin/sh
 repo="$1"
 dir="$2"
-mkdir $dir || exit 1
-cd $dir
-git-init-db
-git fetch "$repo" && ( git-rev-parse FETCH_HEAD > .git/HEAD )
+mkdir "$dir" &&
+D=$(
+    (cd "$dir" && git-init-db && pwd)
+) || exit 1
+
+# See if repo is a local directory.
+if (
+	cd "$repo/objects" 2>/dev/null
+)
+then
+	# See if we can hardlink and drop "l" if not.
+	sample_file=$(cd "$repo" && find objects -type f -print | sed -e 1q)
+
+	# objects directory should not be empty since we are cloning!
+	test -f "$repo/$sample_file" || exit 
+
+	if ln "$repo/$sample_file" "$D/.git/objects/sample" 2>/dev/null
+	then
+	    l=l
+	else
+	    l=
+	fi &&
+	rm -f "$D/.git/objects/sample" &&
+
+	cd "$repo" &&
+	find objects -type f -print |
+	cpio -puam$l "$D/.git" || exit 1
+
+	# FETCH_HEAD is always HEAD because we do not do the
+	# extra parameter to "git fetch".
+	pwd
+	cat "HEAD" >"$D/.git/FETCH_HEAD"
+	cd "$D"
+else
+	cd "$D" && git fetch "$repo"
+fi && ( git-rev-parse FETCH_HEAD > .git/HEAD )

Compilation finished at Mon Jul  4 14:37:29