lib-http: client: Implicitly switch ioloop for global shared client c…

…ontext.

If the new ioloop is NULL, close the shared client context. In that case all
shared hosts, peers and idle connetions are closed and destroyed. The context
just remains as a container for settings and shared context. This is only
allowed when there are no clients left.

src/lib-http/http-client.c

@@ -611,6 +611,34 @@ http_client_context_remove_client(struct http_client_context *cctx,
 	http_client_context_update_settings(cctx);
 }
 
+static void http_client_context_close(struct http_client_context *cctx)
+{
+	struct connection *_conn, *_conn_next;
+	struct http_client_host_shared *hshared;
+	struct http_client_peer_shared *pshared;
+
+	/* Switching to NULL ioloop;
+	   close all hosts, peers, and connections */
+	i_assert(cctx->clients_list == NULL);
+
+	_conn = cctx->conn_list->connections;
+	while (_conn != NULL) {
+		struct http_client_connection *conn =
+			(struct http_client_connection *)_conn;
+		_conn_next = _conn->next;
+		http_client_connection_close(&conn);
+		_conn = _conn_next;
+	}
+	while (cctx->hosts_list != NULL) {
+		hshared = cctx->hosts_list;
+		http_client_host_shared_free(&hshared);
+	}
+	while (cctx->peers_list != NULL) {
+		pshared = cctx->peers_list;
+		http_client_peer_shared_close(&pshared);
+	}
+}
+
 void http_client_context_switch_ioloop(struct http_client_context *cctx)
 {
 	struct connection *_conn = cctx->conn_list->connections;
@@ -644,6 +672,18 @@ static void http_client_global_context_free(void)
 	http_client_context_unref(&http_client_global_context);
 }
 
+static void
+http_client_global_context_ioloop_switched(
+	struct ioloop *prev_ioloop ATTR_UNUSED)
+{
+	i_assert(http_client_global_context != NULL);
+	if (current_ioloop == NULL) {
+		http_client_context_close(http_client_global_context);
+		return;
+	}
+	http_client_context_switch_ioloop(http_client_global_context);
+}
+
 struct http_client_context *http_client_get_global_context(void)
 {
 	if (http_client_global_context != NULL)
@@ -654,5 +694,6 @@ struct http_client_context *http_client_get_global_context(void)
 	http_client_global_context = http_client_context_create(&set);
 	/* keep this a bit higher than lib-ssl-iostream */
 	lib_atexit_priority(http_client_global_context_free, LIB_ATEXIT_PRIORITY_LOW-1);
+	io_loop_add_switch_callback(http_client_global_context_ioloop_switched);
 	return http_client_global_context;
 }