wlr_raster: Introduce new abstraction

types/meson.build

@@ -58,6 +58,7 @@ wlr_files += files(
 	'wlr_presentation_time.c',
 	'wlr_primary_selection_v1.c',
 	'wlr_primary_selection.c',
+	'wlr_raster.c',
 	'wlr_region.c',
 	'wlr_relative_pointer_v1.c',
 	'wlr_screencopy_v1.c',

types/wlr_raster.c

@@ -0,0 +1,83 @@
+#include <assert.h>
+#include <wlr/types/wlr_raster.h>
+#include <wlr/types/wlr_buffer.h>
+#include <wlr/render/wlr_texture.h>
+#include "util/signal.h"
+
+struct wlr_raster *wlr_raster_create(struct wlr_buffer *buffer) {
+	struct wlr_raster *raster = calloc(1, sizeof(*raster));
+	if (!raster) {
+		return NULL;
+	}
+
+	wl_list_init(&raster->sources);
+	wl_signal_init(&raster->events.destroy);
+
+	assert(buffer);
+	raster->width = buffer->width;
+	raster->height = buffer->height;
+	raster->buffer = wlr_buffer_lock(buffer);
+	
+	raster->n_locks = 1;
+
+	return raster;
+}
+
+void wlr_raster_remove_buffer(struct wlr_raster *raster) {
+	assert(raster->buffer);
+	assert(!wl_list_empty(&raster->sources));
+
+	wlr_buffer_unlock(raster->buffer);
+	raster->buffer = NULL;
+}
+
+static void raster_consider_destroy(struct wlr_raster *raster) {
+	if (raster->n_locks > 0) {
+		return;
+	}
+
+	wlr_signal_emit_safe(&raster->events.destroy, NULL);
+
+	struct wlr_texture *texture, *texture_tmp;
+	wl_list_for_each_safe(texture, texture_tmp, &raster->sources, link) {
+		wlr_texture_destroy(texture);
+	}
+
+	wlr_buffer_unlock(raster->buffer);
+	free(raster);
+}
+
+struct wlr_raster *wlr_raster_lock(struct wlr_raster *raster) {
+	raster->n_locks++;
+	return raster;
+}
+
+void wlr_raster_unlock(struct wlr_raster *raster) {
+	if (!raster) {
+		return;
+	}
+
+	assert(raster->n_locks > 0);
+
+	raster->n_locks--;
+	raster_consider_destroy(raster);
+}
+
+void wlr_raster_attach(struct wlr_raster *raster, struct wlr_texture *texture) {
+	assert(texture);
+	assert(!texture->raster);
+	assert(texture->width == raster->width && texture->height == raster->height);
+
+	wl_list_insert(&raster->sources, &texture->link);
+	texture->raster = raster;
+}
+
+void wlr_raster_detach(struct wlr_raster *raster, struct wlr_texture *texture) {
+	if (!texture) {
+		return;
+	}
+	
+	assert(texture->raster == raster);
+	texture->raster = NULL;
+	wl_list_remove(&texture->link);
+}