cat-file: split batch_one_object into two stages

There are really two things going on in this function:

  1. We convert the name we got on stdin to a sha1.

  2. We look up and print information on the sha1.

Let's split out the second half so that we can call it
separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/cat-file.c

@@ -251,10 +251,31 @@ static void print_object_or_die(struct batch_options *opt, struct expand_data *d
 	}
 }
 
+static void batch_object_write(const char *obj_name, struct batch_options *opt,
+			       struct expand_data *data)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
+		printf("%s missing\n", obj_name);
+		fflush(stdout);
+		return;
+	}
+
+	strbuf_expand(&buf, opt->format, expand_format, data);
+	strbuf_addch(&buf, '\n');
+	batch_write(opt, buf.buf, buf.len);
+	strbuf_release(&buf);
+
+	if (opt->print_contents) {
+		print_object_or_die(opt, data);
+		batch_write(opt, "\n", 1);
+	}
+}
+
 static void batch_one_object(const char *obj_name, struct batch_options *opt,
 			     struct expand_data *data)
 {
-	struct strbuf buf = STRBUF_INIT;
 	struct object_context ctx;
 	int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 	enum follow_symlinks_result result;
@@ -294,21 +315,7 @@ static void batch_one_object(const char *obj_name, struct batch_options *opt,
 		return;
 	}
 
-	if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
+	batch_object_write(obj_name, opt, data);
-		printf("%s missing\n", obj_name);
-		fflush(stdout);
-		return;
-	}
-
-	strbuf_expand(&buf, opt->format, expand_format, data);
-	strbuf_addch(&buf, '\n');
-	batch_write(opt, buf.buf, buf.len);
-	strbuf_release(&buf);
-
-	if (opt->print_contents) {
-		print_object_or_die(opt, data);
-		batch_write(opt, "\n", 1);
-	}
 }
 
 static int batch_objects(struct batch_options *opt)