odb_pack_keep(): stop generating keepfile name

The odb_pack_keep() function generates the name of a .keep
file and opens it. This has two problems:

  1. It requires a fixed-size buffer to create the filename
     and doesn't notice when the result is truncated.

  2. Of the two callers, one sometimes wants to open a
     filename it already has, which makes things awkward (it
     has to do so manually, and skips the leading-directory
     creation).

Instead, let's have odb_pack_keep() just open the file.
Generating the name isn't hard, and a future patch will
switch callers over to odb_pack_name() anyway.

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

builtin/index-pack.c

@@ -1402,10 +1402,10 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
 		int keep_fd, keep_msg_len = strlen(keep_msg);
 
 		if (!keep_name)
-			keep_fd = odb_pack_keep(name, sizeof(name), sha1);
-		else
-			keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
+			snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
+				 get_object_directory(), sha1_to_hex(sha1));
 
+		keep_fd = odb_pack_keep(keep_name ? keep_name : name);
 		if (keep_fd < 0) {
 			if (errno != EEXIST)
 				die_errno(_("cannot write keep file '%s'"),

cache.h

@@ -1578,11 +1578,11 @@ extern int odb_mkstemp(char *template, size_t limit, const char *pattern);
 extern char *odb_pack_name(struct strbuf *buf, const unsigned char *sha1, const char *ext);
 
 /*
- * Create a pack .keep file in the object database's pack directory, for
- * a pack with checksum "sha1". The return value is a file descriptor opened
- * for writing, or -1 on error. The name of the keep file is written to "name".
+ * Create a pack .keep file named "name" (which should generally be the output
+ * of odb_pack_name). Returns a file descriptor opened for writing, or -1 on
+ * error.
  */
-extern int odb_pack_keep(char *name, size_t namesz, const unsigned char *sha1);
+extern int odb_pack_keep(const char *name);
 
 /*
  * mmap the index file for the specified packfile (if it is not

environment.c

@@ -296,18 +296,16 @@ int odb_mkstemp(char *template, size_t limit, const char *pattern)
 	return xmkstemp_mode(template, mode);
 }
 
-int odb_pack_keep(char *name, size_t namesz, const unsigned char *sha1)
+int odb_pack_keep(const char *name)
 {
 	int fd;
 
-	snprintf(name, namesz, "%s/pack/pack-%s.keep",
-		 get_object_directory(), sha1_to_hex(sha1));
 	fd = open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
 	if (0 <= fd)
 		return fd;
 
 	/* slow path */
-	safe_create_leading_directories(name);
+	safe_create_leading_directories_const(name);
 	return open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
 }
 

fast-import.c

@@ -944,7 +944,9 @@ static char *keep_pack(const char *curr_index_name)
 	static const char *keep_msg = "fast-import";
 	int keep_fd;
 
-	keep_fd = odb_pack_keep(name, sizeof(name), pack_data->sha1);
+	snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
+		 get_object_directory(), sha1_to_hex(pack_data->sha1));
+	keep_fd = odb_pack_keep(name);
 	if (keep_fd < 0)
 		die_errno("cannot create keep file");
 	write_or_die(keep_fd, keep_msg, strlen(keep_msg));