[PATCH] git-submodule: New subcommand 'summary' (2) - hard work

[Ping Yin <pkufranky@gmail.com>]

This patch does the hard work of submodule summary and finally gives
output shown in last patch.

Signed-off-by: Ping Yin <pkufranky@gmail.com>
---
 git-submodule.sh |   68 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 67 insertions(+), 1 deletions(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index 0e81484..cccb539 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -292,7 +292,73 @@ modules_summary()
 	# TODO: quote module names containing space or tab
 	test -n "$modules" &&
 	echo "# Submodules modified: "$modules &&
-	echo "#"
+	echo "#" &&
+	git diff $cache_option --raw $head -- $modules |
+	grep '^:160000\|:000000 160000' |
+	cut -c2- |
+	while read mod_src mod_dst sha1_src sha1_dst status name
+	do
+		sha1_dst=$(echo $sha1_dst | cut -c1-7)
+		sha1_src=$(echo $sha1_src | cut -c1-7)
+		check_dst=t
+		check_src=t
+		case $status in
+		D)
+			check_dst=
+			;;
+		A)
+			check_src=
+			;;
+		esac
+
+		(
+			errmsg=
+			unfound_src=
+			unfound_dst=
+
+			test -z "$check_src" ||
+			GIT_DIR="$name/.git" git-rev-parse $sha1_src >&/dev/null ||
+			unfound_src=t
+
+			test -z "$check_dst" ||
+			GIT_DIR="$name/.git" git-rev-parse $sha1_dst >&/dev/null ||
+			unfound_dst=t
+
+			case "$unfound_src,$unfound_dst" in
+			t,)
+				errmsg="  Warn: $name doesn't contain commit $sha1_src"
+				;;
+			,t)
+				errmsg="  Warn: $name doesn't contain commit $sha1_dst"
+				;;
+			t,t)
+				errmsg="  Warn: $name doesn't contain commits $sha1_src and $sha1_dst"
+				;;
+			*)
+				left=
+				right=
+				test -n "$check_src" &&
+				left=$(GIT_DIR="$name/.git" git log --pretty=format:"  <%s" \
+				${check_dst:+$sha1_dst..}$sha1_src 2>/dev/null)
+
+				test -n "$check_dst" &&
+				right=$(GIT_DIR="$name/.git" git log --reverse --pretty=format:"  >%s" \
+				${check_src:+$sha1_src..}$sha1_dst 2>/dev/null)
+				;;
+			esac
+
+			echo "* $name $sha1_src...$sha1_dst:"
+			if test -n "$errmsg"
+			then
+				echo "$errmsg"
+			else
+				test -n "$left" && echo "$left"
+				test -n "$right" && echo "$right"
+			fi
+			echo
+		) | sed 's/^/# /'
+	done
+
 	cd "$cwd"
 }
 #
-- 
1.5.4.rc2.9.gf5146-dirty