rebase: extract merge code to new source file

Extract the code for merge-based rebase to git-rebase--merge.sh.

Suggested-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Martin von Zweigbergk <martin.von.zweigbergk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

.gitignore

@@ -103,6 +103,7 @@
 /git-read-tree
 /git-rebase
 /git-rebase--interactive
+/git-rebase--merge
 /git-receive-pack
 /git-reflog
 /git-relink

Makefile

@@ -370,6 +370,7 @@ SCRIPT_SH += git-mergetool.sh
 SCRIPT_SH += git-pull.sh
 SCRIPT_SH += git-quiltimport.sh
 SCRIPT_SH += git-rebase--interactive.sh
+SCRIPT_SH += git-rebase--merge.sh
 SCRIPT_SH += git-rebase.sh
 SCRIPT_SH += git-repack.sh
 SCRIPT_SH += git-request-pull.sh

git-rebase--merge.sh

@@ -0,0 +1,154 @@
+#!/bin/sh
+#
+# Copyright (c) 2010 Junio C Hamano.
+#
+
+. git-sh-setup
+
+prec=4
+
+read_state () {
+	onto_name=$(cat "$state_dir"/onto_name) &&
+	end=$(cat "$state_dir"/end) &&
+	msgnum=$(cat "$state_dir"/msgnum)
+}
+
+continue_merge () {
+	test -d "$state_dir" || die "$state_dir directory does not exist"
+
+	unmerged=$(git ls-files -u)
+	if test -n "$unmerged"
+	then
+		echo "You still have unmerged paths in your index"
+		echo "did you forget to use git add?"
+		die "$resolvemsg"
+	fi
+
+	cmt=`cat "$state_dir/current"`
+	if ! git diff-index --quiet --ignore-submodules HEAD --
+	then
+		if ! git commit --no-verify -C "$cmt"
+		then
+			echo "Commit failed, please do not call \"git commit\""
+			echo "directly, but instead do one of the following: "
+			die "$resolvemsg"
+		fi
+		if test -z "$GIT_QUIET"
+		then
+			printf "Committed: %0${prec}d " $msgnum
+		fi
+		echo "$cmt $(git rev-parse HEAD^0)" >> "$state_dir/rewritten"
+	else
+		if test -z "$GIT_QUIET"
+		then
+			printf "Already applied: %0${prec}d " $msgnum
+		fi
+	fi
+	test -z "$GIT_QUIET" &&
+	GIT_PAGER='' git log --format=%s -1 "$cmt"
+
+	# onto the next patch:
+	msgnum=$(($msgnum + 1))
+	echo "$msgnum" >"$state_dir/msgnum"
+}
+
+call_merge () {
+	cmt="$(cat "$state_dir/cmt.$1")"
+	echo "$cmt" > "$state_dir/current"
+	hd=$(git rev-parse --verify HEAD)
+	cmt_name=$(git symbolic-ref HEAD 2> /dev/null || echo HEAD)
+	msgnum=$(cat "$state_dir/msgnum")
+	eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
+	eval GITHEAD_$hd='$onto_name'
+	export GITHEAD_$cmt GITHEAD_$hd
+	if test -n "$GIT_QUIET"
+	then
+		GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
+	fi
+	test -z "$strategy" && strategy=recursive
+	eval 'git-merge-$strategy' $strategy_opts '"$cmt^" -- "$hd" "$cmt"'
+	rv=$?
+	case "$rv" in
+	0)
+		unset GITHEAD_$cmt GITHEAD_$hd
+		return
+		;;
+	1)
+		git rerere $allow_rerere_autoupdate
+		die "$resolvemsg"
+		;;
+	2)
+		echo "Strategy: $rv $strategy failed, try another" 1>&2
+		die "$resolvemsg"
+		;;
+	*)
+		die "Unknown exit code ($rv) from command:" \
+			"git-merge-$strategy $cmt^ -- HEAD $cmt"
+		;;
+	esac
+}
+
+finish_rb_merge () {
+	move_to_original_branch
+	git notes copy --for-rewrite=rebase < "$state_dir"/rewritten
+	if test -x "$GIT_DIR"/hooks/post-rewrite &&
+		test -s "$state_dir"/rewritten; then
+		"$GIT_DIR"/hooks/post-rewrite rebase < "$state_dir"/rewritten
+	fi
+	rm -r "$state_dir"
+	say All done.
+}
+
+case "$action" in
+continue)
+	read_state
+	continue_merge
+	while test "$msgnum" -le "$end"
+	do
+		call_merge "$msgnum"
+		continue_merge
+	done
+	finish_rb_merge
+	exit
+	;;
+skip)
+	read_state
+	git rerere clear
+	msgnum=$(($msgnum + 1))
+	while test "$msgnum" -le "$end"
+	do
+		call_merge "$msgnum"
+		continue_merge
+	done
+	finish_rb_merge
+	exit
+	;;
+esac
+
+mkdir -p "$state_dir"
+echo "$onto_name" > "$state_dir/onto_name"
+echo "$head_name" > "$state_dir/head-name"
+echo "$onto" > "$state_dir/onto"
+echo "$orig_head" > "$state_dir/orig-head"
+echo "$GIT_QUIET" > "$state_dir/quiet"
+
+msgnum=0
+for cmt in `git rev-list --reverse --no-merges "$revisions"`
+do
+	msgnum=$(($msgnum + 1))
+	echo "$cmt" > "$state_dir/cmt.$msgnum"
+done
+
+echo 1 >"$state_dir/msgnum"
+echo $msgnum >"$state_dir/end"
+
+end=$msgnum
+msgnum=1
+
+while test "$msgnum" -le "$end"
+do
+	call_merge "$msgnum"
+	continue_merge
+done
+
+finish_rb_merge