Make function to refill http queue a callback

This eliminates the last function provided by the code using http.h as
a global symbol, so it should be possible to have multiple programs
using http.h in the same executable, and it also adds an argument to
that callback, so that info can be passed into the callback without
being global.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http-fetch.c

@@ -317,7 +317,7 @@ static void release_object_request(struct object_request *obj_req)
 }
 
 #ifdef USE_CURL_MULTI
-int fill_active_slot(void)
+static int fill_active_slot(void *unused)
 {
 	struct object_request *obj_req;
 
@@ -1035,6 +1035,10 @@ int main(int argc, const char **argv)
 	alt->packs = NULL;
 	alt->next = NULL;
 
+#ifdef USE_CURL_MULTI
+	add_fill_function(NULL, fill_active_slot);
+#endif
+
 	if (pull(commits, commit_id, write_ref, url))
 		rc = 1;
 

http-push.c

@@ -795,7 +795,7 @@ static void finish_request(struct transfer_request *request)
 }
 
 #ifdef USE_CURL_MULTI
-int fill_active_slot(void)
+static int fill_active_slot(void *unused)
 {
 	struct transfer_request *request = request_queue_head;
 
@@ -2496,6 +2496,7 @@ int main(int argc, char **argv)
 				objects_to_send);
 #ifdef USE_CURL_MULTI
 		fill_active_slots();
+		add_fill_function(NULL, fill_active_slot);
 #endif
 		finish_all_active_slots();
 

http.c

@@ -391,13 +391,39 @@ int start_active_slot(struct active_request_slot *slot)
 }
 
 #ifdef USE_CURL_MULTI
+struct fill_chain {
+	void *data;
+	int (*fill)(void *);
+	struct fill_chain *next;
+};
+
+static struct fill_chain *fill_cfg = NULL;
+
+void add_fill_function(void *data, int (*fill)(void *))
+{
+	struct fill_chain *new = malloc(sizeof(*new));
+	struct fill_chain **linkp = &fill_cfg;
+	new->data = data;
+	new->fill = fill;
+	new->next = NULL;
+	while (*linkp)
+		linkp = &(*linkp)->next;
+	*linkp = new;
+}
+
 void fill_active_slots(void)
 {
 	struct active_request_slot *slot = active_queue_head;
 
-	while (active_requests < max_requests)
-		if (!fill_active_slot())
+	while (active_requests < max_requests) {
+		struct fill_chain *fill;
+		for (fill = fill_cfg; fill; fill = fill->next)
+			if (fill->fill(fill->data))
+				break;
+
+		if (!fill)
 			break;
+	}
 
 	while (slot != NULL) {
 		if (!slot->in_use && slot->curl != NULL) {

http.h

@@ -70,10 +70,8 @@ extern void release_active_slot(struct active_request_slot *slot);
 
 #ifdef USE_CURL_MULTI
 extern void fill_active_slots(void);
+extern void add_fill_function(void *data, int (*fill)(void *));
 extern void step_active_slots(void);
-
-/* Provided by the program using http. */
-extern int fill_active_slot(void);
 #endif
 
 extern void http_init(void);