subtree: add git subtree use and ignore commands

Tell split to use or ignore larger sections of the history. In most cases
split does this automatically based on metadata from subtree add.

Signed-off-by: Tom Clarkson <[email protected]>

Author: tqc

contrib/subtree/git-subtree.sh

@@ -9,13 +9,15 @@ then
 	set -- -h
 fi
 OPTS_SPEC="\
-git subtree add   --prefix=<prefix> <commit>
-git subtree add   --prefix=<prefix> <repository> <ref>
-git subtree merge --prefix=<prefix> <commit>
-git subtree pull  --prefix=<prefix> <repository> <ref>
-git subtree push  --prefix=<prefix> <repository> <ref>
-git subtree split --prefix=<prefix> <commit>
-git subtree map   --prefix=<prefix> <mainline> <subtree>
+git subtree add    --prefix=<prefix> <commit>
+git subtree add    --prefix=<prefix> <repository> <ref>
+git subtree merge  --prefix=<prefix> <commit>
+git subtree pull   --prefix=<prefix> <repository> <ref>
+git subtree push   --prefix=<prefix> <repository> <ref>
+git subtree split  --prefix=<prefix> <commit>
+git subtree map    --prefix=<prefix> <mainline> <subtree>
+git subtree ignore --prefix=<prefix> <commit>
+git subtree use    --prefix=<prefix> <commit>
 --
 h,help        show the help
 q             quiet
@@ -162,7 +164,7 @@ command="$1"
 shift
 
 case "$command" in
-add|merge|pull|map)
+add|merge|pull|map|ignore|use)
 	default=
 	;;
 split|push)
@@ -433,6 +435,18 @@ find_mainline_ref () {
 	done
 }
 
+exclude_processed_refs () {
+		if test -r "$cachedir/processed"
+		then
+			cat "$cachedir/processed" |
+			while read rev
+			do
+				debug "read $rev"
+				echo "^$rev"
+			done
+		fi
+}
+
 copy_commit () {
 	# We're going to set some environment vars here, so
 	# do it in a subshell to get rid of them safely later
@@ -798,20 +812,60 @@ cmd_add_commit () {
 }
 
 cmd_map () {
-	oldrev="$1"
-	newrev="$2"
 
-	if test -z "$oldrev"
+	if test -z "$1"
 	then
 		die "You must provide a revision to map"
 	fi
 
+	oldrev=$(git rev-parse --revs-only "$1") || exit $?
+	newrev=
+
+	if test -n "$2"
+	then
+		newrev=$(git rev-parse --revs-only "$2") || exit $?
+	fi
+
 	cache_setup || exit $?
 	cache_set "$oldrev" "$newrev"
 
 	say "Mapped $oldrev => $newrev"
 }
 
+cmd_ignore () {
+	revs=$(git rev-parse $default --revs-only "$@") || exit $?
+	ensure_single_rev $revs
+
+	say "Ignoring $revs"
+
+	cache_setup || exit $?
+
+	git rev-list $revs |
+	while read rev
+	do
+		cache_set "$rev" ""
+	done
+
+	echo "$revs" >>"$cachedir/processed"
+}
+
+cmd_use () {
+	revs=$(git rev-parse $default --revs-only "$@") || exit $?
+	ensure_single_rev $revs
+
+	say "Using existing subtree $revs"
+
+	cache_setup || exit $?
+
+	git rev-list $revs |
+	while read rev
+	do
+		cache_set "$rev" "$rev"
+	done
+
+	echo "$revs" >>"$cachedir/processed"
+}
+
 cmd_split () {
 	debug "Splitting $dir..."
 	cache_setup || exit $?
@@ -829,7 +883,7 @@ cmd_split () {
 		done
 	fi
 
-	unrevs="$(find_existing_splits "$dir" "$revs")"
+	unrevs="$(find_existing_splits "$dir" "$revs") $(exclude_processed_refs)"
 
 	mainline="$(find_mainline_ref "$dir" "$revs")"
 	if test -n "$mainline"