revert: refactor merge recursive code into its own function

The code that is used to do a recursive merge is extracted from
the revert_or_cherry_pick() function and put into a new
do_recursive_merge() function.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/revert.c

@@ -279,18 +279,69 @@ static NORETURN void die_dirty_index(const char *me)
 	}
 }
 
+static void do_recursive_merge(struct commit *base, struct commit *next,
+			       const char *base_label, const char *next_label,
+			       unsigned char *head, struct strbuf *msgbuf,
+			       char *defmsg)
+{
+	struct merge_options o;
+	struct tree *result, *next_tree, *base_tree, *head_tree;
+	int clean, index_fd;
+	static struct lock_file index_lock;
+
+	index_fd = hold_locked_index(&index_lock, 1);
+
+	read_cache();
+	init_merge_options(&o);
+	o.ancestor = base ? base_label : "(empty tree)";
+	o.branch1 = "HEAD";
+	o.branch2 = next ? next_label : "(empty tree)";
+
+	head_tree = parse_tree_indirect(head);
+	next_tree = next ? next->tree : empty_tree();
+	base_tree = base ? base->tree : empty_tree();
+
+	clean = merge_trees(&o,
+			    head_tree,
+			    next_tree, base_tree, &result);
+
+	if (active_cache_changed &&
+	    (write_cache(index_fd, active_cache, active_nr) ||
+	     commit_locked_index(&index_lock)))
+		die("%s: Unable to write new index file", me);
+	rollback_lock_file(&index_lock);
+
+	if (!clean) {
+		int i;
+		strbuf_addstr(msgbuf, "\nConflicts:\n\n");
+		for (i = 0; i < active_nr;) {
+			struct cache_entry *ce = active_cache[i++];
+			if (ce_stage(ce)) {
+				strbuf_addch(msgbuf, '\t');
+				strbuf_addstr(msgbuf, ce->name);
+				strbuf_addch(msgbuf, '\n');
+				while (i < active_nr && !strcmp(ce->name,
+						active_cache[i]->name))
+					i++;
+			}
+		}
+		write_message(msgbuf, defmsg);
+		fprintf(stderr, "Automatic %s failed.%s\n",
+			me, help_msg(commit_name));
+		rerere(allow_rerere_auto);
+		exit(1);
+	}
+	write_message(msgbuf, defmsg);
+	fprintf(stderr, "Finished one %s.\n", me);
+}
+
 static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
-	int i, index_fd, clean;
 	struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
-
 	char *defmsg = git_pathdup("MERGE_MSG");
-	struct merge_options o;
-	struct tree *result, *next_tree, *base_tree, *head_tree;
-	static struct lock_file index_lock;
 	struct strbuf msgbuf = STRBUF_INIT;
 
 	git_config(git_default_config, NULL);
@@ -321,8 +372,6 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	}
 	discard_cache();
 
-	index_fd = hold_locked_index(&index_lock, 1);
-
 	if (!commit->parents) {
 		if (action == REVERT)
 			die ("Cannot revert a root commit");
@@ -395,47 +444,8 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		}
 	}
 
-	read_cache();
-	init_merge_options(&o);
-	o.ancestor = base ? base_label : "(empty tree)";
-	o.branch1 = "HEAD";
-	o.branch2 = next ? next_label : "(empty tree)";
-
-	head_tree = parse_tree_indirect(head);
-	next_tree = next ? next->tree : empty_tree();
-	base_tree = base ? base->tree : empty_tree();
-
-	clean = merge_trees(&o,
-			    head_tree,
-			    next_tree, base_tree, &result);
-
-	if (active_cache_changed &&
-	    (write_cache(index_fd, active_cache, active_nr) ||
-	     commit_locked_index(&index_lock)))
-		die("%s: Unable to write new index file", me);
-	rollback_lock_file(&index_lock);
-
-	if (!clean) {
-		strbuf_addstr(&msgbuf, "\nConflicts:\n\n");
-		for (i = 0; i < active_nr;) {
-			struct cache_entry *ce = active_cache[i++];
-			if (ce_stage(ce)) {
-				strbuf_addch(&msgbuf, '\t');
-				strbuf_addstr(&msgbuf, ce->name);
-				strbuf_addch(&msgbuf, '\n');
-				while (i < active_nr && !strcmp(ce->name,
-						active_cache[i]->name))
-					i++;
-			}
-		}
-		write_message(&msgbuf, defmsg);
-		fprintf(stderr, "Automatic %s failed.%s\n",
-			me, help_msg(commit_name));
-		rerere(allow_rerere_auto);
-		exit(1);
-	}
-	write_message(&msgbuf, defmsg);
-	fprintf(stderr, "Finished one %s.\n", me);
+	do_recursive_merge(base, next, base_label, next_label,
+			   head, &msgbuf, defmsg);
 
 	/*
 	 *