[PATCH] Don't fetch objects that exist in the local repository

Be sure not to fetch objects that already exist in the local repository.
The main process loop no longer performs this check, http-fetch now checks
prior to starting a new request queue entry and when fetch_object() is called,
and local-fetch now checks when fetch_object() is called.

As discussed in this thread: http://marc.theaimsgroup.com/?t=112854890500001

Signed-off-by: Nick Hengeveld <nickh@reactrix.com>

fetch.c

@@ -165,7 +165,7 @@ static int loop(void)
 		 * the queue because we needed to fetch it first.
 		 */
 		if (! (obj->flags & TO_SCAN)) {
-			if (!has_sha1_file(obj->sha1) && fetch(obj->sha1)) {
+			if (fetch(obj->sha1)) {
 				report_missing(obj->type
 					       ? obj->type
 					       : "object", obj->sha1);

http-fetch.c

@@ -489,7 +489,10 @@ void process_request_queue()
 
 	while (active_requests < max_requests && request != NULL) {
 		if (request->state == WAITING) {
-			start_request(request);
+			if (has_sha1_file(request->sha1))
+				release_request(request);
+			else
+				start_request(request);
 			curl_multi_perform(curlm, &num_transfers);
 		}
 		request = request->next;
@@ -890,6 +893,11 @@ static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 	if (request == NULL)
 		return error("Couldn't find request for %s in the queue", hex);
 
+	if (has_sha1_file(request->sha1)) {
+		release_request(request);
+		return 0;
+	}
+
 #ifdef USE_CURL_MULTI
 	int num_transfers;
 	while (request->state == WAITING) {

local-fetch.c

@@ -166,7 +166,10 @@ static int fetch_file(const unsigned char *sha1)
 
 int fetch(unsigned char *sha1)
 {
-	return fetch_file(sha1) && fetch_pack(sha1);
+	if (has_sha1_file(sha1))
+		return 0;
+	else
+		return fetch_file(sha1) && fetch_pack(sha1);
 }
 
 int fetch_ref(char *ref, unsigned char *sha1)