weston-log: merge functions that destroy different types of subscribers

Log subscriber API is not type-safe. File and flight recorder
subscribers are created with functions that return
weston_log_subscriber objects. But there's a problem: to destroy
these objects you have to call the right function for each type
of subscriber, and a user calling the wrong destroy function
wouldn't get a warning.

Merge functions that destroy different types of subscribers, making
the log subscriber API type-safe.

Signed-off-by: Leandro Ribeiro <leandrohr@riseup.net>

compositor/main.c

@@ -3381,8 +3381,8 @@ out:
 	weston_log_scope_destroy(log_scope);
 	log_scope = NULL;
 	weston_log_ctx_destroy(log_ctx);
-	weston_log_subscriber_destroy_log(logger);
+	weston_log_subscriber_destroy(logger);
-	weston_log_subscriber_destroy_flight_rec(flight_rec);
+	weston_log_subscriber_destroy(flight_rec);
 
 out_signals:
 	for (i = ARRAY_LENGTH(signals) - 1; i >= 0; i--)

include/libweston/weston-log.h

@@ -110,6 +110,9 @@ char *
 weston_log_scope_timestamp(struct weston_log_scope *scope,
 			     char *buf, size_t len);
 
+void
+weston_log_subscriber_destroy(struct weston_log_subscriber *subscriber);
+
 void
 weston_log_subscribe(struct weston_log_context *log_ctx,
 		     struct weston_log_subscriber *subscriber,
@@ -118,15 +121,9 @@ weston_log_subscribe(struct weston_log_context *log_ctx,
 struct weston_log_subscriber *
 weston_log_subscriber_create_log(FILE *dump_to);
 
-void
-weston_log_subscriber_destroy_log(struct weston_log_subscriber *sub);
-
 struct weston_log_subscriber *
 weston_log_subscriber_create_flight_rec(size_t size);
 
-void
-weston_log_subscriber_destroy_flight_rec(struct weston_log_subscriber *sub);
-
 void
 weston_log_subscriber_display_flight_rec(struct weston_log_subscriber *sub);
 

libweston/weston-log-file.c

@@ -54,14 +54,21 @@ weston_log_file_write(struct weston_log_subscriber *sub,
 	fwrite(data, len, 1, stream->file);
 }
 
+static void
+weston_log_subscriber_destroy_log(struct weston_log_subscriber *subscriber)
+{
+	struct weston_debug_log_file *file = to_weston_debug_log_file(subscriber);
+	free(file);
+}
+
 /** Creates a file type of subscriber
  *
- * Should be destroyed using weston_log_subscriber_destroy_log()
+ * Should be destroyed using weston_log_subscriber_destroy()
  *
  * @param dump_to if specified, used for writing data to
  * @returns a weston_log_subscriber object or NULL in case of failure
  *
- * @sa weston_log_subscriber_destroy_log
+ * @sa weston_log_subscriber_destroy
  *
  */
 WL_EXPORT struct weston_log_subscriber *
@@ -79,6 +86,7 @@ weston_log_subscriber_create_log(FILE *dump_to)
 
 
 	file->base.write = weston_log_file_write;
+	file->base.destroy = weston_log_subscriber_destroy_log;
 	file->base.destroy_subscription = NULL;
 	file->base.complete = NULL;
 
@@ -86,15 +94,3 @@ weston_log_subscriber_create_log(FILE *dump_to)
 
 	return &file->base;
 }
-
-/** Destroy the subscriber created with weston_log_subscriber_create_log
- *
- * @param subscriber the weston_log_subscriber object to destroy
- *
- */
-WL_EXPORT void
-weston_log_subscriber_destroy_log(struct weston_log_subscriber *subscriber)
-{
-	struct weston_debug_log_file *file = to_weston_debug_log_file(subscriber);
-	free(file);
-}

libweston/weston-log-flight-rec.c

@@ -218,10 +218,24 @@ weston_log_subscriber_display_flight_rec(struct weston_log_subscriber *sub)
 	weston_log_subscriber_display_flight_rec_data(rb, rb->file);
 }
 
+static void
+weston_log_subscriber_destroy_flight_rec(struct weston_log_subscriber *sub)
+{
+	struct weston_debug_log_flight_recorder *flight_rec = to_flight_recorder(sub);
+
+	/* Resets weston_primary_flight_recorder_ring_buffer to NULL if it
+	 * is the destroyed subscriber */
+	if (weston_primary_flight_recorder_ring_buffer == &flight_rec->rb)
+		weston_primary_flight_recorder_ring_buffer = NULL;
+
+	free(flight_rec->rb.buf);
+	free(flight_rec);
+}
+
 /** Create a flight recorder type of subscriber
  *
  * Allocates both the flight recorder and the underlying ring buffer. Use
- * weston_log_subscriber_destroy_flight_rec() to clean-up.
+ * weston_log_subscriber_destroy() to clean-up.
  *
  * @param size specify the maximum size (in bytes) of the backing storage
  * for the flight recorder
@@ -241,6 +255,7 @@ weston_log_subscriber_create_flight_rec(size_t size)
 		return NULL;
 
 	flight_rec->base.write = weston_log_flight_recorder_write;
+	flight_rec->base.destroy = weston_log_subscriber_destroy_flight_rec;
 	flight_rec->base.destroy_subscription = NULL;
 	flight_rec->base.complete = NULL;
 	wl_list_init(&flight_rec->base.subscription_list);
@@ -260,27 +275,6 @@ weston_log_subscriber_create_flight_rec(size_t size)
 	return &flight_rec->base;
 }
 
-/** Destroys the weston_log_subscriber object created with
- * weston_log_subscriber_create_flight_rec()
- *
- * @param sub the weston_log_subscriber object
- *
- * This also resets weston_primary_flight_recorder_ring_buffer to NULL if it
- * is the destroyed subscriber.
- */
-WL_EXPORT void
-weston_log_subscriber_destroy_flight_rec(struct weston_log_subscriber *sub)
-{
-	struct weston_debug_log_flight_recorder *flight_rec;
-
-	flight_rec = to_flight_recorder(sub);
-	if (weston_primary_flight_recorder_ring_buffer == &flight_rec->rb)
-		weston_primary_flight_recorder_ring_buffer = NULL;
-
-	free(flight_rec->rb.buf);
-	free(flight_rec);
-}
-
 /** Retrieve flight recorder ring buffer contents, could be useful when
  * implementing an assert()-like wrapper.
  *

libweston/weston-log-internal.h

@@ -52,6 +52,8 @@ struct weston_log_subscription;
 struct weston_log_subscriber {
 	/** write the data pointed by @param data */
 	void (*write)(struct weston_log_subscriber *sub, const char *data, size_t len);
+	/** For destroying the subscriber */
+	void (*destroy)(struct weston_log_subscriber *sub);
 	/** For the type of streams that required additional destroy operation
 	 * for destroying the stream */
 	void (*destroy_subscription)(struct weston_log_subscriber *sub);
@@ -79,7 +81,6 @@ weston_log_subscription_add(struct weston_log_scope *scope,
 void
 weston_log_subscription_remove(struct weston_log_subscription *sub);
 
-
 void
 weston_log_bind_weston_debug(struct wl_client *client,
 			     void *data, uint32_t version, uint32_t id);

libweston/weston-log-wayland.c

@@ -180,6 +180,7 @@ stream_create(struct weston_log_context *log_ctx, const char *name,
 	stream->resource = stream_resource;
 
 	stream->base.write = weston_log_debug_wayland_write;
+	stream->base.destroy = NULL;
 	stream->base.destroy_subscription = weston_log_debug_wayland_to_destroy;
 	stream->base.complete = weston_log_debug_wayland_complete;
 	wl_list_init(&stream->base.subscription_list);

libweston/weston-log.c

@@ -939,6 +939,21 @@ weston_log_scope_timestamp(struct weston_log_scope *scope,
 	return buf;
 }
 
+/** Destroy a file type or a flight-rec type subscriber.
+ *
+ * They are created, respectively, with weston_log_subscriber_create_log()
+ * and weston_log_subscriber_create_flight_rec()
+ *
+ * @param subscriber the weston_log_subscriber object to destroy
+ *
+ * @ingroup log
+ */
+WL_EXPORT void
+weston_log_subscriber_destroy(struct weston_log_subscriber *subscriber)
+{
+	subscriber->destroy(subscriber);
+}
+
 /** Subscribe to a scope
  *
  * Creates a subscription which is used to subscribe the \p subscriber