[PATCH] ls-tree enhancements

This adds '-r' (recursive) option and '-z' (NUL terminated)
option to ls-tree.  I need it so that the merge-trees (formerly
known as git-merge.perl) script does not need to create any
temporary dircache while merging.  It used to use show-files on
a temporary dircache to get the list of files in the ancestor
tree, and also used the dircache to store the result of its
automerge.  I probably still need it for the latter reason, but
with this patch not for the former reason anymore.

It is relative to bb95843a5a0f397270819462812735ee29796fb4
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ls-tree.c

@@ -5,45 +5,117 @@
  */
 #include "cache.h"
 
-static int list(unsigned char *sha1)
+int line_termination = '\n';
+int recursive = 0;
+
+struct path_prefix {
+	struct path_prefix *prev;
+	const char *name;
+};
+
+static void print_path_prefix(struct path_prefix *prefix)
 {
-	void *buffer;
-	unsigned long size;
-	char type[20];
+	if (prefix) {
+		if (prefix->prev)
+			print_path_prefix(prefix->prev);
+		fputs(prefix->name, stdout);
+		putchar('/');
+	}
+}
+
+static void list_recursive(void *buffer,
+			  unsigned char *type,
+			  unsigned long size,
+			  struct path_prefix *prefix)
+{
+	struct path_prefix this_prefix;
+	this_prefix.prev = prefix;
 
-	buffer = read_sha1_file(sha1, type, &size);
-	if (!buffer)
-		die("unable to read sha1 file");
 	if (strcmp(type, "tree"))
 		die("expected a 'tree' node");
+
 	while (size) {
-		int len = strlen(buffer)+1;
-		unsigned char *sha1 = buffer + len;
-		char *path = strchr(buffer, ' ')+1;
+		int namelen = strlen(buffer)+1;
+		void *eltbuf;
+		char elttype[20];
+		unsigned long eltsize;
+		unsigned char *sha1 = buffer + namelen;
+		char *path = strchr(buffer, ' ') + 1;
 		unsigned int mode;
-		unsigned char *type;
 
-		if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
+		if (size < namelen + 20 || sscanf(buffer, "%o", &mode) != 1)
 			die("corrupt 'tree' file");
 		buffer = sha1 + 20;
-		size -= len + 20;
+		size -= namelen + 20;
+
 		/* XXX: We do some ugly mode heuristics here.
 		 * It seems not worth it to read each file just to get this
-		 * and the file size. -- pasky@ucw.cz */
-		type = S_ISDIR(mode) ? "tree" : "blob";
-		printf("%03o\t%s\t%s\t%s\n", mode, type, sha1_to_hex(sha1), path);
+		 * and the file size. -- pasky@ucw.cz
+		 * ... that is, when we are not recursive -- junkio@cox.net
+		 */
+		eltbuf = (recursive ? read_sha1_file(sha1, elttype, &eltsize) :
+			  NULL);
+		if (! eltbuf) {
+			if (recursive)
+				error("cannot read %s", sha1_to_hex(sha1));
+			type = S_ISDIR(mode) ? "tree" : "blob";
+		}
+		else
+			type = elttype;
+
+		printf("%03o\t%s\t%s\t", mode, type, sha1_to_hex(sha1));
+		print_path_prefix(prefix);
+		fputs(path, stdout);
+		putchar(line_termination);
+
+		if (eltbuf && !strcmp(type, "tree")) {
+			this_prefix.name = path;
+			list_recursive(eltbuf, elttype, eltsize, &this_prefix);
+		}
+		free(eltbuf);
 	}
+}
+
+static int list(unsigned char *sha1)
+{
+	void *buffer;
+	unsigned long size;
+	char type[20];
+
+	buffer = read_sha1_file(sha1, type, &size);
+	if (!buffer)
+		die("unable to read sha1 file");
+	list_recursive(buffer, type, size, NULL);
 	return 0;
 }
 
+static void _usage(void)
+{
+	usage("ls-tree [-r] [-z] <key>");
+}
+
 int main(int argc, char **argv)
 {
 	unsigned char sha1[20];
 
+	while (1 < argc && argv[1][0] == '-') {
+		switch (argv[1][1]) {
+		case 'z':
+			line_termination = 0;
+			break;
+		case 'r':
+			recursive = 1;
+			break;
+		default:
+			_usage();
+		}
+		argc--; argv++;
+	}
+
 	if (argc != 2)
-		usage("ls-tree <key>");
+		_usage();
 	if (get_sha1_hex(argv[1], sha1) < 0)
-		usage("ls-tree <key>");
+		_usage();
 	sha1_file_directory = getenv(DB_ENVIRONMENT);
 	if (!sha1_file_directory)
 		sha1_file_directory = DEFAULT_DB_ENVIRONMENT;