[PATCH v3 3/4] filter-branch: stash away ref map in a branch
With "--state-branch=<branchname>" option, the mapping from old object names and filtered ones in ./map/ directory is stashed away in the object database, and the one from the previous run is read to populate the ./map/ directory, allowing for incremental updates of large trees.
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
---
I have been using this as part of the device tree extraction from the Linux
kernel source since 2013, about time I sent the patch upstream!
v2:
- added several preceding cleanup patches, including:
- new: use of mktag --allow-missing tagger.
- split-out: preserving $GIT_*.
- use git rev-parse rather than git show-ref.
- improved error handling for Perl sub-processes.
- collapsed some shell pipelines involving piping output of git and ls into
Perl into the Perl scripts.
- style fixes for conditionals and sub-shells.
- fixup indentation.
- added documentation.
- improved commit message.
---
Documentation/git-filter-branch.txt | 8 +++++-
git-filter-branch.sh | 49 ++++++++++++++++++++++++++++++++++++-
2 files changed, 55 insertions(+), 2 deletions(-)
Show changes to 2 files +55 −2
Documentation/git-filter-branch.txt, git-filter-branch.sh
diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index 9e5169aa6..bebdcdec5 100644
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -14,7 +14,7 @@ SYNOPSIS
[--commit-filter <command>] [--tag-name-filter <command>]
[--subdirectory-filter <directory>] [--prune-empty]
[--original <namespace>] [-d <directory>] [-f | --force]
- [--] [<rev-list options>...]
+ [--state-branch <branch>] [--] [<rev-list options>...]
DESCRIPTION
-----------
@@ -198,6 +198,12 @@ to other tags will be rewritten to point to the underlying commit.
directory or when there are already refs starting with
'refs/original/', unless forced.
+--state-branch <branch>::
+ This option will cause the mapping from old to new objects to
+ be loaded from named branch upon startup and saved as a new
+ commit to that branch upon exit, enabling incremental of large
+ trees. If '<branch>' does not exist it will be created.
+
<rev-list options>...::
Arguments for 'git rev-list'. All positive refs included by
these options are rewritten. You may also specify options
diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 9edb94206..956869b8e 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -86,7 +86,7 @@ USAGE="[--setup <command>] [--env-filter <command>]
[--parent-filter <command>] [--msg-filter <command>]
[--commit-filter <command>] [--tag-name-filter <command>]
[--subdirectory-filter <directory>] [--original <namespace>]
- [-d <directory>] [-f | --force]
+ [-d <directory>] [-f | --force] [--state-branch <branch>]
[--] [<rev-list options>...]"
OPTIONS_SPEC=
@@ -106,6 +106,7 @@ filter_msg=cat
filter_commit=
filter_tag_name=
filter_subdir=
+state_branch=
orig_namespace=refs/original/
force=
prune_empty=
@@ -181,6 +182,9 @@ do
--original)
orig_namespace=$(expr "$OPTARG/" : '\(.*[^/]\)/*$')/
;;
+ --state-branch)
+ state_branch="$OPTARG"
+ ;;
*)
usage
;;
@@ -259,6 +263,26 @@ export GIT_INDEX_FILE
# map old->new commit ids for rewriting parents
mkdir ../map || die "Could not create map/ directory"
+if test -n "$state_branch"
+then
+ state_commit=$(git rev-parse --no-flags --revs-only "$state_branch")
+ if test -n "$state_commit"
+ then
+ echo "Populating map from $state_branch ($state_commit)" 1>&2
+ perl -e'open(MAP, "-|", "git show $ARGV[0]:filter.map") or die;
+ while (<MAP>) {
+ m/(.*):(.*)/ or die;
+ open F, ">../map/$1" or die;
+ print F "$2" or die;
+ close(F) or die;
+ }
+ close(MAP) or die;' "$state_commit" \
+ || die "Unable to load state from $state_branch:filter.map"
+ else
+ echo "Branch $state_branch does not exist. Will create" 1>&2
+ fi
+fi
+
# we need "--" only if there are no path arguments in $@
nonrevs=$(git rev-parse --no-revs "$@") || exit
if test -z "$nonrevs"
@@ -590,6 +614,29 @@ test -z "$ORIG_GIT_COMMITTER_DATE" || {
export GIT_COMMITTER_DATE
}
+if test -n "$state_branch"
+then
+ echo "Saving rewrite state to $state_branch" 1>&2
+ state_blob=$(
+ perl -e'opendir D, "../map" or die;
+ open H, "|-", "git hash-object -w --stdin" or die;
+ foreach (sort readdir(D)) {
+ next if m/^\.\.?$/;
+ open F, "<../map/$_" or die;
+ chomp($f = <F>);
+ print H "$_:$f\n" or die;
+ }
+ close(H) or die;' || die "Unable to save state")
+ state_tree=$(/bin/echo -e "100644 blob $state_blob\tfilter.map" | git mktree)
+ if test -n "$state_commit"
+ then
+ state_commit=$(/bin/echo "Sync" | git commit-tree "$state_tree" -p "$state_commit")
+ else
+ state_commit=$(/bin/echo "Sync" | git commit-tree "$state_tree" )
+ fi
+ git update-ref "$state_branch" "$state_commit"
+fi
+
cd "$orig_dir"
rm -rf "$tempdir"
--
2.11.0
Ian Campbell