[PATCH] Add --info-only option to git-update-cache.

Add --info-only option to git-update-cache.

[JC demangled whitespace from the posted patch himself because he
 liked it so much.  Also adjusted to the index_fd() interface
 slightly done differently from the original one.]

Signed-off-by: Bryan Larsen <bryan.larsen@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/git-update-cache.txt

@@ -14,6 +14,7 @@ SYNOPSIS
 	     [--ignore-missing]
 	     [--force-remove]
 	     [--cacheinfo <mode> <object> <file>]\*
+	     [--info-only]
 	     [--] [<file>]\*
 
 DESCRIPTION
@@ -47,6 +48,11 @@ OPTIONS
 --cacheinfo <mode> <object> <path>::
 	Directly insert the specified info into the cache.
 	
+--info-only::
+	Do not create objects in the object database for all
+	<file> arguments that follow this flag; just insert
+	their object IDs into the cache.
+
 --force-remove::
 	Remove the file from the index even when the working directory
 	still has such a file. (Implies --remove.)
@@ -80,15 +86,27 @@ the stat entry is out of date.
 For example, you'd want to do this after doing a "git-read-tree", to link
 up the stat cache details with the proper files.
 
-Using --cacheinfo
------------------
-'--cacheinfo' is used to register a file that is not in the current
-working directory.  This is useful for minimum-checkout merging.
+Using --cacheinfo or --info-only
+--------------------------------
+'--cacheinfo' is used to register a file that is not in the
+current working directory.  This is useful for minimum-checkout
+merging.
 
-To pretend you have a file with mode and sha1 at path, say:
+  To pretend you have a file with mode and sha1 at path, say:
 
    $ git-update-cache --cacheinfo mode sha1 path
 
+'--info-only' is used to register files without placing them in the object
+database.  This is useful for status-only repositories.
+
+Both '--cacheinfo' and '--info-only' behave similarly: the index is updated
+but the object database isn't.  '--cacheinfo' is useful when the object is
+in the database but the file isn't available locally.  '--info-only' is
+useful when the file is available, but you do not wish to update the
+object database.
+
+Examples
+--------
 To update and refresh only the files already checked out:
 
    git-checkout-cache -n -f -a && git-update-cache --ignore-missing --refresh

update-cache.c

@@ -12,7 +12,7 @@
  * like "git-update-cache *" and suddenly having all the object
  * files be revision controlled.
  */
-static int allow_add = 0, allow_remove = 0, allow_replace = 0, not_new = 0, quiet = 0;
+static int allow_add = 0, allow_remove = 0, allow_replace = 0, not_new = 0, quiet = 0, info_only = 0;
 static int force_remove;
 
 /* Three functions to allow overloaded pointer return; see linux/err.h */
@@ -68,7 +68,7 @@ static int add_file_to_cache(char *path)
 		fd = open(path, O_RDONLY);
 		if (fd < 0)
 			return -1;
-		if (index_fd(ce->sha1, fd, &st, 1, NULL) < 0)
+		if (index_fd(ce->sha1, fd, &st, !info_only, NULL) < 0)
 			return -1;
 		break;
 	case S_IFLNK:
@@ -77,7 +77,12 @@ static int add_file_to_cache(char *path)
 			free(target);
 			return -1;
 		}
-		if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
+		if (info_only) {
+			unsigned char hdr[50];
+			int hdrlen;
+			write_sha1_file_prepare(target, st.st_size, "blob",
+						ce->sha1, hdr, &hdrlen);
+		} else if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
 			return -1;
 		free(target);
 		break;
@@ -382,6 +387,10 @@ int main(int argc, char **argv)
 				i += 3;
 				continue;
 			}
+			if (!strcmp(path, "--info-only")) {
+				info_only = 1;
+				continue;
+			}
 			if (!strcmp(path, "--force-remove")) {
 				force_remove = 1;
 				continue;