[PATCH] git-submodule: provide easy way of adding new submodules

[Sven Verdoolaege <skimo@kotnet.org>]

To make a submodule effectively usable, the path and
a URL where the submodule can be cloned need to be stored
in .gitmodules.  This subcommand takes care of setting
this information after cloning the new submodule.
Only the index is updated, so, if needed, the user may still
change the URL or switch to a different branch of the submodule
before committing.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 Documentation/git-submodule.txt |    8 +++++
 git-submodule.sh                |   65 +++++++++++++++++++++++++++++++++++---
 2 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index f8fb80f..bf9cbf9 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -8,11 +8,19 @@ git-submodule - Initialize, update or inspect submodules
 
 SYNOPSIS
 --------
+'git-submodule' [--quiet] add <repository> [<path>]
 'git-submodule' [--quiet] [--cached] [status|init|update] [--] [<path>...]
 
 
 COMMANDS
 --------
+add::
+	Add the given repository as a submodule at the given path
+	to the changeset to be committed next.  In particular, the
+	repository is cloned at the specified path, added to the
+	changeset and registered in .gitmodules.   If no path is
+	specified, the path is deduced from the repository specification.
+
 status::
 	Show the status of the submodules. This will print the SHA-1 of the
 	currently checked out commit for each submodule, along with the
diff --git a/git-submodule.sh b/git-submodule.sh
index 89a3885..85ae275 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1,13 +1,14 @@
 #!/bin/sh
 #
-# git-submodules.sh: init, update or list git submodules
+# git-submodules.sh: add, init, update or list git submodules
 #
 # Copyright (c) 2007 Lars Hjemli
 
-USAGE='[--quiet] [--cached] [status|init|update] [--] [<path>...]'
+USAGE='[--quiet] [--cached] [add <repo>|status|init|update] [--] [<path>...]'
 . git-sh-setup
 require_work_tree
 
+add=
 init=
 update=
 status=
@@ -25,6 +26,17 @@ say()
 	fi
 }
 
+get_repo_base() {
+	(
+		cd "`/bin/pwd`" &&
+		cd "$1" || cd "$1.git" &&
+		{
+			cd .git
+			pwd
+		}
+	) 2>/dev/null
+}
+
 #
 # Map submodule path to submodule name
 #
@@ -66,6 +78,41 @@ module_clone()
 }
 
 #
+# Add a new submodule to the working tree, .gitmodules and the index
+#
+# $@ = repo [path]
+#
+module_add()
+{
+	repo=$1
+	path=$2
+
+	# Turn the source into an absolute path if
+	# it is local
+	if base=$(get_repo_base "$repo"); then
+		repo="$base"
+	fi
+
+	# Guess path from repo if not specified or strip trailing slashes
+	if test -z "$path"; then
+		path=$(echo "$repo" | sed -e 's|/*$||' -e 's|:*/*\.git$||' -e 's|.*[/:]||g')
+	else
+		path=$(echo "$path" | sed -e 's|/*$||')
+	fi
+
+	module_clone "$path" "$repo" || exit
+	(unset GIT_DIR && cd "$path" && git checkout -q) ||
+	die "Unable to checkout submodule '$path'"
+	git add "$path" ||
+	die "Failed to add submodule '$path'"
+
+	GIT_CONFIG=.gitmodules git config submodule."$path".path "$path" &&
+	GIT_CONFIG=.gitmodules git config submodule."$path".url "$repo" &&
+	git add .gitmodules ||
+	die "Failed to register submodule '$path'"
+}
+
+#
 # Register submodules in .git/config
 #
 # $@ = requested paths (default to all)
@@ -173,6 +220,9 @@ modules_list()
 while case "$#" in 0) break ;; esac
 do
 	case "$1" in
+	add)
+		add=1
+		;;
 	init)
 		init=1
 		;;
@@ -201,14 +251,17 @@ do
 	shift
 done
 
-case "$init,$update,$status,$cached" in
-1,,,)
+case "$add,$init,$update,$status,$cached" in
+1,,,,)
+	module_add "$@"
+	;;
+,1,,,)
 	modules_init "$@"
 	;;
-,1,,)
+,,1,,)
 	modules_update "$@"
 	;;
-,,*,*)
+,,,*,*)
 	modules_list "$@"
 	;;
 *)
-- 
1.5.2.1.1088.ge05f4-dirty