[PATCH v2 2/3] 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 |   70 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 69 insertions(+), 1 deletions(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index 8009a8d..8322771 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -380,7 +380,75 @@ cmd_summary()
 	# TODO: quote module names containing space or tab
 	test -n "$modules" &&
 	echo "# Submodules modified: "$modules &&
-	echo "#"
+	echo "#" &&
+	git diff $cache_option --raw $head -- $modules |
+	grep '^:160000\|:[0-9]\+ 160000' |
+	cut -c2- |
+	while read mod_src mod_dst sha1_src sha1_dst status name
+	do
+		sha1_src=$(echo $sha1_src | sed -e 's/\.\.\.//')
+		sha1_dst=$(echo $sha1_dst | sed -e 's/\.\.\.//')
+		check_src=$(echo $mod_src | grep 160000)
+		check_dst=$(echo $mod_dst | grep 160000)
+		errmsg=
+		unfound_src=
+		unfound_dst=
+
+		test -z "$check_src" ||
+		GIT_DIR="$name/.git" git-rev-parse --verify $sha1_src^0 >/dev/null 2>&1 ||
+		unfound_src=t
+
+		test -z "$check_dst" ||
+		GIT_DIR="$name/.git" git-rev-parse --verify $sha1_dst^0 >/dev/null 2>&1 ||
+		unfound_dst=t
+
+		case "$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..}$sha1_dst 2>/dev/null)
+			;;
+		esac
+
+		sha1_src=$(echo $sha1_src | cut -c1-7)
+		sha1_dst=$(echo $sha1_dst | cut -c1-7)
+		if test $status = T
+		then
+			if test $mod_dst = 160000
+			then
+				echo "* $name $sha1_src(blob)->$sha1_dst(submodule):"
+			else
+				echo "* $name $sha1_src(submodule)->$sha1_dst(blob):"
+			fi
+		else
+			echo "* $name $sha1_src...$sha1_dst:"
+		fi
+		if test -n "$errmsg"
+		then
+			# Don't give error msg for modification whose dst is not submodule, i.e. deleted or changed to blob
+			test $mod_dst = 160000 && echo "$errmsg"
+		else
+			test -n "$left" && echo "$left"
+			test -n "$right" && echo "$right"
+		fi
+		echo
+	done | sed -e 's/^/# /'
+
 	cd "$cwd"
 }
 #
-- 
1.5.4.3.347.g5314c