[PATCH wayland v2] Add API to install protocol loggers on the server wl_display

Giulio Camuffo giuliocamuffo at gmail.com
Thu Apr 7 11:37:44 UTC 2016


The new wl_display_add_protocol_logger allows to set a function as
a logger, which will get called when a new request is received or an
event is sent.
This is akin to setting WAYLAND_DEBUG=1, but more powerful because it
can be enabled at run time and allows to show the log e.g. in a UI view.

Signed-off-by: Giulio Camuffo <giulio.camuffo at kdab.com>
---

v2: changed the logger function to pass a struct wl_log_message* with all
    the relevant data instead of a string.

 src/wayland-server-core.h |  21 ++++++++++
 src/wayland-server.c      | 100 +++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 115 insertions(+), 6 deletions(-)

diff --git a/src/wayland-server-core.h b/src/wayland-server-core.h
index 9980c29..07a42fc 100644
--- a/src/wayland-server-core.h
+++ b/src/wayland-server-core.h
@@ -514,6 +514,27 @@ wl_shm_buffer_create(struct wl_client *client,
 
 void wl_log_set_handler_server(wl_log_func_t handler);
 
+enum wl_protocol_logger_direction {
+    WL_PROTOCOL_LOGGER_INCOMING,
+    WL_PROTOCOL_LOGGER_OUTGOING,
+};
+
+struct wl_log_message {
+	struct wl_resource *resource;
+	int message_opcode;
+	const struct wl_message *message;
+	int arguments_count;
+	const union wl_argument *arguments;
+};
+
+typedef void (*wl_protocol_logger_func_t)(void *, enum wl_protocol_logger_direction,
+					  const struct wl_log_message *);
+void wl_add_protocol_logger(struct wl_display *display,
+                            wl_protocol_logger_func_t, void *user_data);
+
+void wl_remove_protocol_logger(struct wl_display *display,
+                            wl_protocol_logger_func_t, void *user_data);
+
 #ifdef  __cplusplus
 }
 #endif
diff --git a/src/wayland-server.c b/src/wayland-server.c
index e47ccec..18bbec8 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -95,6 +95,7 @@ struct wl_display {
 	struct wl_list global_list;
 	struct wl_list socket_list;
 	struct wl_list client_list;
+	struct wl_list protocol_loggers;
 
 	struct wl_signal destroy_signal;
 	struct wl_signal create_client_signal;
@@ -121,10 +122,45 @@ struct wl_resource {
 	void *data;
 	int version;
 	wl_dispatcher_func_t dispatcher;
+	struct wl_resource *parent;
+};
+
+struct wl_protocol_logger {
+	struct wl_list link;
+	wl_protocol_logger_func_t func;
+	void *user_data;
 };
 
 static int debug_server = 0;
 
+static void
+closure_log(struct wl_resource *resource,
+	    struct wl_closure *closure, int send)
+{
+	struct wl_object *object = &resource->object;
+	struct wl_display *display = resource->client->display;
+	struct wl_protocol_logger *protocol_logger;
+	struct wl_log_message message;
+
+	if (debug_server)
+		wl_closure_print(closure, object, send);
+
+	if (!wl_list_empty(&display->protocol_loggers)) {
+		message.resource = resource;
+		message.message_opcode = closure->opcode;
+		message.message = closure->message;
+		message.arguments_count = closure->count;
+		message.arguments = closure->args;
+		wl_list_for_each(protocol_logger,
+				 &display->protocol_loggers, link) {
+			protocol_logger->func(protocol_logger->user_data,
+					      send ? WL_PROTOCOL_LOGGER_OUTGOING :
+						     WL_PROTOCOL_LOGGER_INCOMING,
+					      &message);
+		}
+	}
+}
+
 WL_EXPORT void
 wl_resource_post_event_array(struct wl_resource *resource, uint32_t opcode,
 			     union wl_argument *args)
@@ -143,8 +179,7 @@ wl_resource_post_event_array(struct wl_resource *resource, uint32_t opcode,
 	if (wl_closure_send(closure, resource->client->connection))
 		resource->client->error = 1;
 
-	if (debug_server)
-		wl_closure_print(closure, object, true);
+	closure_log(resource, closure, true);
 
 	wl_closure_destroy(closure);
 }
@@ -183,8 +218,7 @@ wl_resource_queue_event_array(struct wl_resource *resource, uint32_t opcode,
 	if (wl_closure_queue(closure, resource->client->connection))
 		resource->client->error = 1;
 
-	if (debug_server)
-		wl_closure_print(closure, object, true);
+	closure_log(resource, closure, true);
 
 	wl_closure_destroy(closure);
 }
@@ -331,8 +365,7 @@ wl_client_connection_data(int fd, uint32_t mask, void *data)
 			break;
 		}
 
-		if (debug_server)
-			wl_closure_print(closure, object, false);
+		closure_log(resource, closure, false);
 
 		if ((resource_flags & WL_MAP_ENTRY_LEGACY) ||
 		    resource->dispatcher == NULL) {
@@ -879,6 +912,7 @@ wl_display_create(void)
 	wl_list_init(&display->socket_list);
 	wl_list_init(&display->client_list);
 	wl_list_init(&display->registry_resource_list);
+	wl_list_init(&display->protocol_loggers);
 
 	wl_signal_init(&display->destroy_signal);
 	wl_signal_init(&display->create_client_signal);
@@ -1463,6 +1497,60 @@ wl_log_set_handler_server(wl_log_func_t handler)
 	wl_log_handler = handler;
 }
 
+/** Adds a new protocol logger.
+ *
+ * When a new protocol message arrives or is sent from the server
+ * all the protocol logger functions will be called, carrying the
+ * \a user_data pointer, the direction of the message (incoming or
+ * outgoing) and the actual message.
+ *
+ * \param func The function to call to log a new protocol message
+ * \param user_data The user data pointer to pass to \a func
+ *
+ * \sa wl_remove_protocol_logger
+ *
+ * \memberof wl_display
+ */
+WL_EXPORT void
+wl_add_protocol_logger(struct wl_display *display,
+		       wl_protocol_logger_func_t func, void *user_data)
+{
+	struct wl_protocol_logger *logger;
+
+	logger = malloc(sizeof *logger);
+	if (!logger)
+		return;
+
+	logger->func = func;
+	logger->user_data = user_data;
+	wl_list_init(&logger->link);
+	wl_list_insert(&display->protocol_loggers, &logger->link);
+}
+
+/** Removes a protocol logger.
+ *
+ * If a protocol logger was previously added with the same \a func and
+ * \a user_data, it will be removed from the display's list so that it
+ * will not be invoked anymore.
+ *
+ * \sa wl_add_protocol_logger
+ *
+ * \memberof wl_display
+ */
+WL_EXPORT void
+wl_remove_protocol_logger(struct wl_display *display,
+		          wl_protocol_logger_func_t func, void *user_data)
+{
+	struct wl_protocol_logger *logger;
+	wl_list_for_each(logger, &display->protocol_loggers, link) {
+		if (logger->func == func && logger->user_data == user_data) {
+			wl_list_remove(&logger->link);
+			free(logger);
+			return;
+		}
+	}
+}
+
 /** Add support for a wl_shm pixel format
  *
  * \param display The display object
-- 
2.8.0



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