[PATCH v2 2/3] filter-branch --blob-filter: speed/flexibility improvements.

From

Avery Pennarun <apenwarr@gmail.com>

Date

Jun 13, 2008, 00:52 UTC

Message-ID

<1213318344-26013-2-git-send-email-apenwarr@gmail.com>

In-Reply-To

<1213318344-26013-1-git-send-email-apenwarr@gmail.com>

Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
---
 Documentation/git-filter-branch.txt |   27 +++++++++++++++++++++++++++
 git-filter-branch.sh                |   27 +++++++++++++++++----------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index ea77f1f..0c5cd0f 100644
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -12,6 +12,7 @@ SYNOPSIS
 	[--index-filter <command>] [--parent-filter <command>]
 	[--msg-filter <command>] [--commit-filter <command>]
 	[--tag-name-filter <command>] [--subdirectory-filter <directory>]
+	[--blob-filter <command]
 	[--original <namespace>] [-d <directory>] [-f | --force]
 	[<rev-list options>...]
 
@@ -149,6 +150,16 @@ to other tags will be rewritten to point to the underlying commit.
 	The result will contain that directory (and only that) as its
 	project root.
 
+--blob-filter <command>::
+	This is the filter for modifying the contents of each file (blob) in
+	the tree.  The contents of a file are provided on stdin, and the new
+	file contents should be provided on stdout.  The pathname of the
+	blob in the current revision is in $GIT_BLOB_PATH. For efficiency,
+	the before/after results of a given blob+filename are only
+	calculated once and then cached, so your filter must always return
+	the same output blob for any given input blob.  You might use this
+	filter for converting CRLF to LF in all your files, for example.
+
 --original <namespace>::
 	Use this option to set the namespace where the original commits
 	will be stored. The default value is 'refs/original'.
@@ -196,6 +207,22 @@ git filter-branch --index-filter 'git update-index --remove filename' HEAD
 
 Now, you will get the rewritten history saved in HEAD.
 
+To convert CRLF to LF in all your files using the "fromdos" program (be
+careful: this will attempt to modify binary files too!):
+
+----------------------------------------------
+git filter-branch --blob-filter 'fromdos' HEAD
+----------------------------------------------
+
+To convert CRLF to LF in all your *.c and *.cpp files:
+
+---------------------------------------------------------
+git filter-branch --blob-filter 'case "$GIT_BLOB_PATH" in
+	*.c|*.cpp) fromdos;;
+	*) cat;;
+esac' HEAD
+---------------------------------------------------------
+
 To set a commit (which typically is at the tip of another
 history) to be the parent of the current initial commit, in
 order to paste the other history behind the current history:
diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index a0d9a79..f1ee263 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -55,19 +55,24 @@ EOF
 eval "$functions"
 
 munge_blobs() {
-	while read mode sha1 stage path
+	while read GIT_BLOB_MODE GIT_BLOB_SHA1 stage GIT_BLOB_PATH
 	do
-		if ! test -r "$workdir/../blob-cache/$sha1"
+		export GIT_BLOB_MODE GIT_BLOB_SHA1 GIT_BLOB_PATH
+		cachefile="$cachedir/$GIT_BLOB_SHA1/$GIT_BLOB_PATH"
+		if ! test -r "$cachefile"
 		then
-			new=`git cat-file blob $sha1 |
-			     eval "$filter_blob" |
-			     git hash-object -w --stdin`
-			printf $new >$workdir/../blob-cache/$sha1
+			new=$(git cat-file blob $GIT_BLOB_SHA1 |
+			      eval "$filter_blob" |
+			      git hash-object -w --stdin)
+			mkdir -p "$(dirname "$cachefile")"
+			echo -n $new >"$cachefile"
+		else
+			read new <"$cachefile"
 		fi
 		printf "%s %s\t%s\n" \
-			"$mode" \
-			$(cat "$workdir/../blob-cache/$sha1") \
-			"$path"
+			"$GIT_BLOB_MODE" \
+			"$new" \
+			"$GIT_BLOB_PATH"
 	done
 }
 
@@ -108,6 +113,7 @@ USAGE="[--env-filter <command>] [--tree-filter <command>] \
 [--index-filter <command>] [--parent-filter <command>] \
 [--msg-filter <command>] [--commit-filter <command>] \
 [--tag-name-filter <command>] [--subdirectory-filter <directory>] \
+[--blob-filter <command>] \
 [--original <namespace>] [-d <directory>] [-f | --force] \
 [<rev-list options>...]"
 
@@ -249,7 +255,8 @@ ret=0
 mkdir ../map || die "Could not create map/ directory"
 
 # cache rewritten blobs for blob filter
-mkdir ../blob-cache || die "Could not create blob-cache/ directory"
+cachedir="$workdir/../blob-cache"
+mkdir "$cachedir" || die "Could not create blob-cache/ directory"
 
 case "$filter_subdir" in
 "")

-- 
1.5.6.rc2.29.g4717e