Verify remote packs, speed up pending request queue

Verify that remote packs exist before using the pack index, add requests to
the beginning of the queue to locate pending requests faster.

Signed-off-by: Nick Hengeveld <nickh@reactrix.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

http-push.c

@@ -727,7 +727,6 @@ void process_waiting_requests(void)
 void add_request(unsigned char *sha1, char *lock_token)
 {
 	struct transfer_request *request = request_queue_head;
-	struct transfer_request *tail;
 	struct packed_git *target;
 
 	while (request != NULL && memcmp(request->sha1, sha1, 20))
@@ -745,17 +744,8 @@ void add_request(unsigned char *sha1, char *lock_token)
 	request->lock_token = lock_token;
 	request->headers = NULL;
 	request->state = NEED_CHECK;
-	request->next = NULL;
-
-	if (request_queue_head == NULL) {
-		request_queue_head = request;
-	} else {
-		tail = request_queue_head;
-		while (tail->next != NULL) {
-			tail = tail->next;
-		}
-		tail->next = request;
-	}
+	request->next = request_queue_head;
+	request_queue_head = request;
 #ifdef USE_CURL_MULTI
 	process_request_queue();
 	process_curl_messages();
@@ -775,13 +765,29 @@ static int fetch_index(unsigned char *sha1)
 	FILE *indexfile;
 	struct active_request_slot *slot;
 
+	/* Don't use the index if the pack isn't there */
+	url = xmalloc(strlen(remote->url) + 65);
+	sprintf(url, "%s/objects/pack/pack-%s.pack", remote->url, hex);
+	slot = get_active_slot();
+	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
+	if (start_active_slot(slot)) {
+		run_active_slot(slot);
+		if (slot->curl_result != CURLE_OK) {
+			free(url);
+			return error("Unable to verify pack %s is available",
+				     hex);
+		}
+	} else {
+		return error("Unable to start request");
+	}
+
 	if (has_pack_index(sha1))
 		return 0;
 
 	if (push_verbosely)
 		fprintf(stderr, "Getting index for pack %s\n", hex);
 
-	url = xmalloc(strlen(remote->url) + 64);
 	sprintf(url, "%s/objects/pack/pack-%s.idx", remote->url, hex);
 
 	filename = sha1_pack_index_name(sha1);
@@ -792,6 +798,8 @@ static int fetch_index(unsigned char *sha1)
 			     filename);
 
 	slot = get_active_slot();
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 	curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
@@ -833,8 +841,6 @@ static int fetch_index(unsigned char *sha1)
 static int setup_index(unsigned char *sha1)
 {
 	struct packed_git *new_pack;
-	if (has_pack_file(sha1))
-		return 0; // don't list this as something we can get
 
 	if (fetch_index(sha1))
 		return -1;
@@ -1610,7 +1616,6 @@ int main(int argc, char **argv)
 	while (request != NULL) {
 		next_request = request->next;
 		release_request(request);
-		free(request);
 		request = next_request;
 	}