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authorJunio C Hamano <gitster@pobox.com>2007-08-01 23:42:36 -0700
committerJunio C Hamano <gitster@pobox.com>2007-08-01 23:42:36 -0700
commit3d5c418ff56645e13bdbd8c9f7d84fdaf7c8494b (patch)
tree1f1a596ee7b69399e2b233d20c7770639e6150e0 /git-clone.sh
parent72a4f4b657846af6c65360d92aa09d8b7f3dfbb0 (diff)
downloadgit-3d5c418ff56645e13bdbd8c9f7d84fdaf7c8494b.tar.gz
git-clone: aggressively optimize local clone behaviour.
This changes the behaviour of cloning from a repository on the local machine, by defaulting to "-l" (use hardlinks to share files under .git/objects) and making "-l" a no-op. A new option, --no-hardlinks, is also added to cause file-level copy of files under .git/objects while still avoiding the normal "pack to pipe, then receive and index pack" network transfer overhead. The old behaviour of local cloning without -l nor -s is availble by specifying the source repository with the newly introduced file:///path/to/repo.git/ syntax (i.e. "same as network" cloning). * With --no-hardlinks (i.e. have all .git/objects/ copied via cpio) would not catch the source repository corruption, and also risks corrupted recipient repository if an alpha-particle hits memory cell while indexing and resolving deltas. As long as the recipient is created uncorrupted, you have a good back-up. * same-as-network is expensive, but it would catch the breakage of the source repository. It still risks corrupted recipient repository due to hardware failure. As long as the recipient is created uncorrupted, you have a good back-up. * The new default on the same filesystem, as long as the source repository is healthy, it is very likely that the recipient would be, too. Also it is very cheap. You do not get any back-up benefit, though. None of the method is resilient against the source repository corruption, so let's discount that from the comparison. Then the difference with and without --no-hardlinks matters primarily if you value the back-up benefit or not. If you want to use the cloned repository as a back-up, then it is cheaper to do a clone with --no-hardlinks and two git-fsck (source before clone, recipient after clone) than same-as-network clone, especially as you are likely to do a git-fsck on the recipient if you are so paranoid anyway. Which leads me to believe that being able to use file:/// is probably a good idea, if only for testability, but probably of little practical value. We default to hardlinked clone for everyday use, and paranoids can use --no-hardlinks as a way to make a back-up. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'git-clone.sh')
-rwxr-xr-xgit-clone.sh64
1 files changed, 35 insertions, 29 deletions
diff --git a/git-clone.sh b/git-clone.sh
index 09225540e6..4c9b1c9710 100755
--- a/git-clone.sh
+++ b/git-clone.sh
@@ -87,7 +87,7 @@ Perhaps git-update-server-info needs to be run there?"
quiet=
local=no
-use_local=no
+use_local_hardlink=yes
local_shared=no
unset template
no_checkout=
@@ -108,9 +108,13 @@ while
no_checkout=yes ;;
*,--na|*,--nak|*,--nake|*,--naked|\
*,-b|*,--b|*,--ba|*,--bar|*,--bare) bare=yes ;;
- *,-l|*,--l|*,--lo|*,--loc|*,--loca|*,--local) use_local=yes ;;
+ *,-l|*,--l|*,--lo|*,--loc|*,--loca|*,--local)
+ use_local_hardlink=yes ;;
+ *,--no-h|*,--no-ha|*,--no-har|*,--no-hard|*,--no-hardl|\
+ *,--no-hardli|*,--no-hardlin|*,--no-hardlink|*,--no-hardlinks)
+ use_local_hardlink=no ;;
*,-s|*,--s|*,--sh|*,--sha|*,--shar|*,--share|*,--shared)
- local_shared=yes; use_local=yes ;;
+ local_shared=yes; ;;
1,--template) usage ;;
*,--template)
shift; template="--template=$1" ;;
@@ -249,34 +253,36 @@ fi
rm -f "$GIT_DIR/CLONE_HEAD"
# We do local magic only when the user tells us to.
-case "$local,$use_local" in
-yes,yes)
+case "$local" in
+yes)
( cd "$repo/objects" ) ||
- die "-l flag seen but repository '$repo' is not local."
+ die "cannot chdir to local '$repo/objects'."
- case "$local_shared" in
- no)
- # See if we can hardlink and drop "l" if not.
- sample_file=$(cd "$repo" && \
- find objects -type f -print | sed -e 1q)
-
- # objects directory should not be empty since we are cloning!
- test -f "$repo/$sample_file" || exit
-
- l=
- if ln "$repo/$sample_file" "$GIT_DIR/objects/sample" 2>/dev/null
- then
- l=l
- fi &&
- rm -f "$GIT_DIR/objects/sample" &&
- cd "$repo" &&
- find objects -depth -print | cpio -pumd$l "$GIT_DIR/" || exit 1
- ;;
- yes)
- mkdir -p "$GIT_DIR/objects/info"
- echo "$repo/objects" >> "$GIT_DIR/objects/info/alternates"
- ;;
- esac
+ if test "$local_shared" = yes
+ then
+ mkdir -p "$GIT_DIR/objects/info"
+ echo "$repo/objects" >>"$GIT_DIR/objects/info/alternates"
+ else
+ l= &&
+ if test "$use_local_hardlink" = yes
+ 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 because
+ # we are cloning!
+ test -f "$repo/$sample_file" || exit
+ if ln "$repo/$sample_file" "$GIT_DIR/objects/sample" 2>/dev/null
+ then
+ rm -f "$GIT_DIR/objects/sample"
+ l=l
+ else
+ echo >&2 "Warning: -l asked but cannot hardlink to $repo"
+ fi
+ fi &&
+ cd "$repo" &&
+ find objects -depth -print | cpio -pumd$l "$GIT_DIR/" || exit 1
+ fi
git-ls-remote "$repo" >"$GIT_DIR/CLONE_HEAD" || exit 1
;;
*)