git-cat-file: Add --batch-check option

This new option allows multiple objects to be specified on stdin. For each
object specified, a line of the following form is printed:

<sha1> SP <type> SP <size> LF

If the object does not exist in the repository, a line of the following form is
printed:

<object> SP missing LF

Signed-off-by: Adam Roben <aroben@apple.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 72 insertions, 2 deletions

diff --git a/builtin-cat-file.c b/builtin-cat-file.c
index a76bb16b49..832cfd184a 100644
--- a/builtin-cat-file.c
+++ b/builtin-cat-file.c
@@ -143,11 +143,48 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
 	return 0;
 }
 
-static const char cat_file_usage[] = "git-cat-file [-t|-s|-e|-p|<type>] <sha1>";
+static int batch_one_object(const char *obj_name)
+{
+	unsigned char sha1[20];
+	enum object_type type;
+	unsigned long size;
+
+	if (!obj_name)
+	   return 1;
+
+	if (get_sha1(obj_name, sha1)) {
+		printf("%s missing\n", obj_name);
+		return 0;
+	}
+
+	type = sha1_object_info(sha1, &size);
+	if (type <= 0)
+		return 1;
+
+	printf("%s %s %lu\n", sha1_to_hex(sha1), typename(type), size);
+
+	return 0;
+}
+
+static int batch_objects(void)
+{
+	struct strbuf buf;
+
+	strbuf_init(&buf, 0);
+	while (strbuf_getline(&buf, stdin, '\n') != EOF) {
+		int error = batch_one_object(buf.buf);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+static const char cat_file_usage[] = "git-cat-file [ [-t|-s|-e|-p|<type>] <sha1> | --batch-check < <list_of_sha1s> ]";
 
 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 {
-	int i, opt = 0;
+	int i, opt = 0, batch_check = 0;
 	const char *exp_type = NULL, *obj_name = NULL;
 
 	git_config(git_default_config);
@@ -155,7 +192,28 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
 	for (i = 1; i < argc; ++i) {
 		const char *arg = argv[i];
 
+		if (!strcmp(arg, "--batch-check")) {
+			if (opt) {
+				error("git-cat-file: Can't use --batch-check with -%c", opt);
+				usage(cat_file_usage);
+			} else if (exp_type) {
+				error("git-cat-file: Can't use --batch-check when a type (\"%s\") is specified", exp_type);
+				usage(cat_file_usage);
+			} else if (obj_name) {
+				error("git-cat-file: Can't use --batch-check when an object (\"%s\") is specified", obj_name);
+				usage(cat_file_usage);
+			}
+
+			batch_check = 1;
+			continue;
+		}
+
 		if (!strcmp(arg, "-t") || !strcmp(arg, "-s") || !strcmp(arg, "-e") || !strcmp(arg, "-p")) {
+			if (batch_check) {
+				error("git-cat-file: Can't use %s with --batch-check", arg);
+				usage(cat_file_usage);
+			}
+
 			exp_type = arg;
 			opt = exp_type[1];
 			continue;
@@ -165,6 +223,11 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
 			usage(cat_file_usage);
 
 		if (!exp_type) {
+			if (batch_check) {
+				error("git-cat-file: Can't specify a type (\"%s\") with --batch-check", arg);
+				usage(cat_file_usage);
+			}
+
 			exp_type = arg;
 			continue;
 		}
@@ -172,10 +235,17 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
 		if (obj_name)
 			usage(cat_file_usage);
 
+		// We should have hit one of the earlier if (batch_check) cases before
+		// getting here.
+		assert(!batch_check);
+
 		obj_name = arg;
 		break;
 	}
 
+	if (batch_check)
+		return batch_objects();
+
 	if (!exp_type || !obj_name)
 		usage(cat_file_usage);