[PATCH weston v2 5/6] Add API to retrieve and iterate over the resources list of a client

[Giulio Camuffo]

To complement on the new resource created signal, this allows to
iterate over the existing resources of a client.

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

v2: - don't cast the function pointer, but make it a two step process
    - make it possible to break the loop early

 src/wayland-private.h     |  2 +-
 src/wayland-server-core.h |  8 ++++++++
 src/wayland-server.c      | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 src/wayland-util.c        |  8 ++++++--
 4 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/src/wayland-private.h b/src/wayland-private.h
index 045109b..b715534 100644
--- a/src/wayland-private.h
+++ b/src/wayland-private.h
@@ -74,7 +74,7 @@ struct wl_map {
 	uint32_t free_list;
 };
 
-typedef void (*wl_iterator_func_t)(void *element, void *data);
+typedef int (*wl_iterator_func_t)(void *element, void *data);
 
 void
 wl_map_init(struct wl_map *map, uint32_t side);
diff --git a/src/wayland-server-core.h b/src/wayland-server-core.h
index bb0a989..647d97c 100644
--- a/src/wayland-server-core.h
+++ b/src/wayland-server-core.h
@@ -216,6 +216,14 @@ void
 wl_client_add_resource_created_listener(struct wl_client *client,
                                         struct wl_listener *listener);
 
+typedef int (*wl_client_for_each_resource_iterator_func_t)(struct wl_resource *,
+                                                           void *user_data);
+
+void
+wl_client_for_each_resource(struct wl_client *client,
+                            wl_client_for_each_resource_iterator_func_t iterator,
+                            void *user_data);
+
 /** \class wl_listener
  *
  * \brief A single listener for Wayland signals
diff --git a/src/wayland-server.c b/src/wayland-server.c
index 067d8a5..98e3bda 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -565,7 +565,7 @@ wl_resource_post_no_memory(struct wl_resource *resource)
 			       WL_DISPLAY_ERROR_NO_MEMORY, "no memory");
 }
 
-static void
+static int
 destroy_resource(void *element, void *data)
 {
 	struct wl_resource *resource = element;
@@ -580,6 +580,8 @@ destroy_resource(void *element, void *data)
 
 	if (!(flags & WL_MAP_ENTRY_LEGACY))
 		free(resource);
+
+	return 0;
 }
 
 WL_EXPORT void
@@ -1603,6 +1605,49 @@ wl_client_add_resource_created_listener(struct wl_client *client,
 	wl_signal_add(&client->resource_created_signal, listener);
 }
 
+struct wl_resource_iterator_context {
+	void *user_data;
+	wl_client_for_each_resource_iterator_func_t it;
+};
+
+static int
+resource_iterator_helper(void *res, void *user_data)
+{
+	struct wl_resource_iterator_context *context = user_data;
+	struct wl_resource *resource = res;
+	return context->it(resource, context->user_data);
+}
+
+/** Iterate over all the resources of a client
+ *
+ * \param client The client object
+ * \param iterator The iterator function
+ * \param user_data The user data pointer
+ *
+ * The function pointed by \a iterator will be called for each
+ * resource owned by the client. The \a user_data will be passed
+ * as the second argument of the iterator function.
+ * If the \a iterator function returns a value less than 0 the loop
+ * will stop.
+ *
+ * Creating and destroying resources while iterating is safe, but new
+ * resources may or may not be picked up by the iterator.
+ *
+ * \memberof wl_client
+ */
+WL_EXPORT void
+wl_client_for_each_resource(struct wl_client *client,
+			    wl_client_for_each_resource_iterator_func_t iterator,
+			    void *user_data)
+{
+	struct wl_resource_iterator_context context = {
+		.user_data = user_data,
+		.it = iterator,
+	};
+
+	wl_map_for_each(&client->objects, resource_iterator_helper, &context);
+}
+
 /** \cond */ /* Deprecated functions below. */
 
 uint32_t
diff --git a/src/wayland-util.c b/src/wayland-util.c
index 7467366..856e53b 100644
--- a/src/wayland-util.c
+++ b/src/wayland-util.c
@@ -363,13 +363,17 @@ static void
 for_each_helper(struct wl_array *entries, wl_iterator_func_t func, void *data)
 {
 	union map_entry *start, *end, *p;
+	int ret;
 
 	start = entries->data;
 	end = (union map_entry *) ((char *) entries->data + entries->size);
 
 	for (p = start; p < end; p++)
-		if (p->data && !map_entry_is_free(*p))
-			func(map_entry_get_data(*p), data);
+		if (p->data && !map_entry_is_free(*p)) {
+			ret = func(map_entry_get_data(*p), data);
+			if (ret < 0)
+				break;
+		}
 }
 
 WL_EXPORT void
-- 
2.9.0