[PATCH 06/17] {fetch,upload}-pack: support narrow repository

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

If $GIT_DIR/narrow is set, fetch-pack will send "narrow-tree" lines to
upload-pack, where the prefixes are passed to rev-list mechanism to
produce a narrow pack.

"narrow-tree" capability is required for this to work.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/git-fetch-pack.txt          |    3 ++
 Documentation/technical/pack-protocol.txt |    3 ++
 builtin/fetch-pack.c                      |    9 +++++++
 upload-pack.c                             |   38 +++++++++++++++++++++++++++-
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-fetch-pack.txt b/Documentation/git-fetch-pack.txt
index 4a8487c..19b0d92 100644
--- a/Documentation/git-fetch-pack.txt
+++ b/Documentation/git-fetch-pack.txt
@@ -25,6 +25,9 @@ This command degenerates to download everything to complete the
 asked refs from the remote side when the local side does not
 have a common ancestor commit.
 
+In narrow repositories, it asks 'git-upload-pack' to send only objects
+within narrow area defined in $GIT_DIR/narrow.
+
 
 OPTIONS
 -------
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index 369f91d..39474d2 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -215,6 +215,9 @@ discovery phase as 'want' lines. Clients MUST send at least one
 obj-id in a 'want' command which did not appear in the response
 obtained through ref discovery.
 
+If client is requesting narrow clone, it must send 'narrow-tree'
+lines before 'want' lines.
+
 If client is requesting a shallow clone, it will now send a 'deepen'
 line with the depth it is requesting.
 
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index dbd8b7b..591e0e4 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -37,6 +37,7 @@ static int marked;
 
 static struct commit_list *rev_list;
 static int non_common_revs, multi_ack, use_sideband;
+const char **narrow_prefix;
 
 static void rev_list_push(struct commit *commit, int mark)
 {
@@ -237,6 +238,12 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 	for_each_ref(rev_list_insert_ref, NULL);
 
 	fetching = 0;
+	narrow_prefix = get_narrow_prefix();
+	if (narrow_prefix) {
+		const char **p = narrow_prefix;
+		while (*p)
+			packet_buf_write(&req_buf, "narrow-tree %s\n", *p++);
+	}
 	for ( ; refs ; refs = refs->next) {
 		unsigned char *remote = refs->old_sha1;
 		const char *remote_hex;
@@ -692,6 +699,8 @@ static struct ref *do_fetch_pack(int fd[2],
 
 	if (is_repository_shallow() && !server_supports("shallow"))
 		die("Server does not support shallow clients");
+	if (narrow_prefix && !server_supports("narrow-tree"))
+		die("Server does not support narrow-tree");
 	if (server_supports("multi_ack_detailed")) {
 		if (args.verbose)
 			fprintf(stderr, "Server supports multi_ack_detailed\n");
diff --git a/upload-pack.c b/upload-pack.c
index cc1983f..f3747e5 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -41,6 +41,8 @@ static int use_sideband;
 static int debug_fd;
 static int advertise_refs;
 static int stateless_rpc;
+const char **narrow_prefix;
+int narrow_prefix_nr;
 
 static void reset_timeout(void)
 {
@@ -118,6 +120,10 @@ static int do_rev_list(int in, int out, void *user_data)
 	revs.simplify_history = 0;
 	if (use_thin_pack)
 		revs.edge_hint = 1;
+	if (narrow_prefix) {
+		revs.prune_data = narrow_prefix;
+		narrow_prefix[narrow_prefix_nr] = NULL;
+	}
 
 	for (i = 0; i < want_obj.nr; i++) {
 		struct object *o = want_obj.objects[i].item;
@@ -154,9 +160,10 @@ static void create_pack_file(void)
 		"corruption on the remote side.";
 	int buffered = -1;
 	ssize_t sz;
-	const char *argv[10];
+	const char **argv;
 	int arg = 0;
 
+	argv = xmalloc(sizeof(*argv)*(11+narrow_prefix_nr));
 	if (shallow_nr) {
 		memset(&rev_list, 0, sizeof(rev_list));
 		rev_list.proc = do_rev_list;
@@ -180,6 +187,11 @@ static void create_pack_file(void)
 		argv[arg++] = "--delta-base-offset";
 	if (use_include_tag)
 		argv[arg++] = "--include-tag";
+	if (narrow_prefix) {
+		argv[arg++] = "--";
+		memcpy(argv+arg, narrow_prefix, narrow_prefix_nr*sizeof(*argv));
+		arg += narrow_prefix_nr;
+	}
 	argv[arg++] = NULL;
 
 	memset(&pack_objects, 0, sizeof(pack_objects));
@@ -307,6 +319,7 @@ static void create_pack_file(void)
 		error("git upload-pack: git-pack-objects died with error.");
 		goto fail;
 	}
+	free(argv);
 	if (shallow_nr && finish_async(&rev_list))
 		goto fail;	/* error was already reported */
 
@@ -500,6 +513,22 @@ static void receive_needs(void)
 		if (debug_fd)
 			write_in_full(debug_fd, line, len);
 
+		if (!prefixcmp(line, "narrow-tree ")) {
+			char *s;
+			int len;
+			len = strlen(line+12);
+			s = malloc(len+1);
+			memcpy(s, line+12, len-1);
+			s[len-1] = '\0'; /* \n */
+			if (s[len-2] == '/')
+				die("trailing slash in narrow prefix not allowed, %s", line);
+
+			narrow_prefix_nr++;
+			narrow_prefix = xrealloc(narrow_prefix,
+						 sizeof(*narrow_prefix)*(narrow_prefix_nr+1));
+			narrow_prefix[narrow_prefix_nr-1] = s;
+			continue;
+		}
 		if (!prefixcmp(line, "shallow ")) {
 			unsigned char sha1[20];
 			struct object *object;
@@ -563,6 +592,9 @@ static void receive_needs(void)
 	if (!use_sideband && daemon_mode)
 		no_progress = 1;
 
+	if (narrow_prefix)
+		use_thin_pack = 0;
+
 	if (depth == 0 && shallows.nr == 0)
 		return;
 	if (depth > 0) {
@@ -620,7 +652,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow no-progress"
-		" include-tag multi_ack_detailed";
+		" include-tag multi_ack_detailed narrow-tree";
 	struct object *o = parse_object(sha1);
 
 	if (!o)
@@ -725,6 +757,8 @@ int main(int argc, char **argv)
 		die("'%s' does not appear to be a git repository", dir);
 	if (is_repository_shallow())
 		die("attempt to fetch/clone from a shallow repository");
+	if (get_narrow_prefix())
+		die("attempt to fetch/clone from a narrow repository");
 	if (getenv("GIT_DEBUG_SEND_PACK"))
 		debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));
 	upload_pack();
-- 
1.7.1.rc1.69.g24c2f7