compositor: introduce weston_buffer_reference
The wl_buffer reference counting API has been inconsistent. You would
manually increment the refcount and register a destroy listener, as
opposed to calling weston_buffer_post_release(), which internally
decremented the refcount, and then removing a list item.
Replace both cases with a single function:
weston_buffer_reference(weston_buffer_reference *ref, wl_buffer *buffer)
Buffer is assigned to ref->buffer, while taking care of all the refcounting
and release posting. You take a reference by passing a non-NULL buffer, and
release a reference by passing NULL as buffer. The function uses an
internal wl_buffer destroy listener, so the pointer gets reset on
destruction automatically.
This is inspired by the pipe_resource_reference() of Mesa, and modified
by krh's suggestion to add struct weston_buffer_reference.
Additionally, when a surface gets destroyed, the associated wl_buffer
will send a release event. Often the buffer is already destroyed on
client side, so the event will be discarded by libwayland-client.
Compositor-drm.c is converted to use weston_buffer_reference.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 27f2c7d..da36cd3 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -118,8 +118,7 @@
struct drm_output *output;
uint32_t fb_id;
int is_client_buffer;
- struct wl_buffer *buffer;
- struct wl_listener buffer_destroy_listener;
+ struct weston_buffer_reference buffer_ref;
};
struct drm_output {
@@ -208,10 +207,7 @@
if (fb->fb_id)
drmModeRmFB(gbm_device_get_fd(gbm), fb->fb_id);
- if (fb->buffer) {
- weston_buffer_post_release(fb->buffer);
- wl_list_remove(&fb->buffer_destroy_listener.link);
- }
+ weston_buffer_reference(&fb->buffer_ref, NULL);
free(data);
}
@@ -231,7 +227,7 @@
fb->bo = bo;
fb->is_client_buffer = 0;
- fb->buffer = NULL;
+ fb->buffer_ref.buffer = NULL;
width = gbm_bo_get_width(bo);
height = gbm_bo_get_height(bo);
@@ -283,26 +279,13 @@
}
static void
-fb_handle_buffer_destroy(struct wl_listener *listener, void *data)
-{
- struct drm_fb *fb = container_of(listener, struct drm_fb,
- buffer_destroy_listener);
-
- fb->buffer = NULL;
-}
-
-static void
drm_fb_set_buffer(struct drm_fb *fb, struct wl_buffer *buffer)
{
- assert(fb->buffer == NULL);
+ assert(fb->buffer_ref.buffer == NULL);
fb->is_client_buffer = 1;
- fb->buffer = buffer;
- fb->buffer->busy_count++;
- fb->buffer_destroy_listener.notify = fb_handle_buffer_destroy;
- wl_signal_add(&fb->buffer->resource.destroy_signal,
- &fb->buffer_destroy_listener);
+ weston_buffer_reference(&fb->buffer_ref, buffer);
}
static int
@@ -340,19 +323,20 @@
struct drm_output *output = (struct drm_output *) _output;
struct drm_compositor *c =
(struct drm_compositor *) output->base.compositor;
+ struct wl_buffer *buffer = es->buffer_ref.buffer;
struct gbm_bo *bo;
if (es->geometry.x != output->base.x ||
es->geometry.y != output->base.y ||
- es->buffer == NULL ||
- es->buffer->width != output->base.current->width ||
- es->buffer->height != output->base.current->height ||
+ buffer == NULL ||
+ buffer->width != output->base.current->width ||
+ buffer->height != output->base.current->height ||
output->base.transform != es->buffer_transform ||
es->transform.enabled)
return NULL;
bo = gbm_bo_import(c->gbm, GBM_BO_IMPORT_WL_BUFFER,
- es->buffer, GBM_BO_USE_SCANOUT);
+ buffer, GBM_BO_USE_SCANOUT);
/* Unable to use the buffer for scanout */
if (!bo)
@@ -369,7 +353,7 @@
return NULL;
}
- drm_fb_set_buffer(output->next, es->buffer);
+ drm_fb_set_buffer(output->next, buffer);
return &output->fb_plane;
}
@@ -601,13 +585,13 @@
if (es->output_mask != (1u << output_base->id))
return NULL;
- if (es->buffer == NULL)
+ if (es->buffer_ref.buffer == NULL)
return NULL;
if (es->alpha != 1.0f)
return NULL;
- if (wl_buffer_is_shm(es->buffer))
+ if (wl_buffer_is_shm(es->buffer_ref.buffer))
return NULL;
if (!drm_surface_transform_supported(es))
@@ -628,7 +612,7 @@
return NULL;
bo = gbm_bo_import(c->gbm, GBM_BO_IMPORT_WL_BUFFER,
- es->buffer, GBM_BO_USE_SCANOUT);
+ es->buffer_ref.buffer, GBM_BO_USE_SCANOUT);
if (!bo)
return NULL;
@@ -645,7 +629,7 @@
return NULL;
}
- drm_fb_set_buffer(s->next, es->buffer);
+ drm_fb_set_buffer(s->next, es->buffer_ref.buffer);
box = pixman_region32_extents(&es->transform.boundingbox);
s->plane.x = box->x1;
@@ -715,7 +699,8 @@
return NULL;
if (c->cursors_are_broken)
return NULL;
- if (es->buffer == NULL || !wl_buffer_is_shm(es->buffer) ||
+ if (es->buffer_ref.buffer == NULL ||
+ !wl_buffer_is_shm(es->buffer_ref.buffer) ||
es->geometry.width > 64 || es->geometry.height > 64)
return NULL;
@@ -742,14 +727,15 @@
return;
}
- if (es->buffer && pixman_region32_not_empty(&output->cursor_plane.damage)) {
+ if (es->buffer_ref.buffer &&
+ pixman_region32_not_empty(&output->cursor_plane.damage)) {
pixman_region32_fini(&output->cursor_plane.damage);
pixman_region32_init(&output->cursor_plane.damage);
output->current_cursor ^= 1;
bo = output->cursor_bo[output->current_cursor];
memset(buf, 0, sizeof buf);
- stride = wl_shm_buffer_get_stride(es->buffer);
- s = wl_shm_buffer_get_data(es->buffer);
+ stride = wl_shm_buffer_get_stride(es->buffer_ref.buffer);
+ s = wl_shm_buffer_get_data(es->buffer_ref.buffer);
for (i = 0; i < es->geometry.height; i++)
memcpy(buf + i * 64, s + i * stride,
es->geometry.width * 4);