render/allocator: add wlr_allocator.buffer_caps

This allows users to know the capabilities of the buffers that
will be allocated. The buffer capability is important to
know when negotiating buffer formats.

include/render/allocator.h

@@ -19,6 +19,9 @@ struct wlr_allocator_interface {
 struct wlr_allocator {
 	const struct wlr_allocator_interface *impl;
 
+	// Capabilites of the buffers created with this allocator
+	uint32_t buffer_caps;
+
 	struct {
 		struct wl_signal destroy;
 	} events;
@@ -44,7 +47,7 @@ struct wlr_buffer *wlr_allocator_create_buffer(struct wlr_allocator *alloc,
 
 // For wlr_allocator implementors
 void wlr_allocator_init(struct wlr_allocator *alloc,
-	const struct wlr_allocator_interface *impl);
+	const struct wlr_allocator_interface *impl, uint32_t buffer_caps);
 
 struct wlr_allocator *allocator_autocreate_with_drm_fd(
 	struct wlr_backend *backend, struct wlr_renderer *renderer, int drm_fd);

render/allocator.c

@@ -11,9 +11,10 @@
 #include "types/wlr_buffer.h"
 
 void wlr_allocator_init(struct wlr_allocator *alloc,
-		const struct wlr_allocator_interface *impl) {
+		const struct wlr_allocator_interface *impl, uint32_t buffer_caps) {
 	assert(impl && impl->destroy && impl->create_buffer);
 	alloc->impl = impl;
+	alloc->buffer_caps = buffer_caps;
 	wl_signal_init(&alloc->events.destroy);
 }
 
@@ -74,5 +75,19 @@ void wlr_allocator_destroy(struct wlr_allocator *alloc) {
 
 struct wlr_buffer *wlr_allocator_create_buffer(struct wlr_allocator *alloc,
 		int width, int height, const struct wlr_drm_format *format) {
-	return alloc->impl->create_buffer(alloc, width, height, format);
+	struct wlr_buffer *buffer =
+		alloc->impl->create_buffer(alloc, width, height, format);
+	if (buffer == NULL) {
+		return NULL;
+	}
+	if (alloc->buffer_caps & WLR_BUFFER_CAP_DATA_PTR) {
+		assert(buffer->impl->get_data_ptr);
+	}
+	if (alloc->buffer_caps & WLR_BUFFER_CAP_DMABUF) {
+		assert(buffer->impl->get_dmabuf);
+	}
+	if (alloc->buffer_caps & WLR_BUFFER_CAP_SHM) {
+		assert(buffer->impl->get_shm);
+	}
+	return buffer;
 }

render/drm_dumb_allocator.c

@@ -15,6 +15,7 @@
 
 #include "render/drm_dumb_allocator.h"
 #include "render/pixel_format.h"
+#include "types/wlr_buffer.h"
 
 static const struct wlr_buffer_impl buffer_impl;
 
@@ -127,7 +128,7 @@ create_err:
 	return NULL;
 }
 
-static bool buffer_get_data_ptr(struct wlr_buffer *wlr_buffer, void **data,
+static bool drm_dumb_buffer_get_data_ptr(struct wlr_buffer *wlr_buffer, void **data,
 		uint32_t *format, size_t *stride) {
 	struct wlr_drm_dumb_buffer *buf = drm_dumb_buffer_from_buffer(wlr_buffer);
 	*data = buf->data;
@@ -152,7 +153,7 @@ static void buffer_destroy(struct wlr_buffer *wlr_buffer) {
 static const struct wlr_buffer_impl buffer_impl = {
 	.destroy = buffer_destroy,
 	.get_dmabuf = buffer_get_dmabuf,
-	.get_data_ptr = buffer_get_data_ptr,
+	.get_data_ptr = drm_dumb_buffer_get_data_ptr,
 };
 
 static const struct wlr_allocator_interface allocator_impl;
@@ -231,7 +232,8 @@ struct wlr_allocator *wlr_drm_dumb_allocator_create(int fd) {
 		free(path);
 		return NULL;
 	}
-	wlr_allocator_init(&alloc->base, &allocator_impl);
+	wlr_allocator_init(&alloc->base, &allocator_impl,
+		WLR_BUFFER_CAP_DATA_PTR | WLR_BUFFER_CAP_DMABUF);
 
 	alloc->drm_fd = drm_fd;
 	wl_list_init(&alloc->buffers);

render/gbm_allocator.c

@@ -7,6 +7,7 @@
 #include <wlr/util/log.h>
 #include <xf86drm.h>
 #include "render/gbm_allocator.h"
+#include "types/wlr_buffer.h"
 
 static const struct wlr_buffer_impl buffer_impl;
 
@@ -181,7 +182,7 @@ struct wlr_allocator *wlr_gbm_allocator_create(int drm_fd) {
 	if (alloc == NULL) {
 		return NULL;
 	}
-	wlr_allocator_init(&alloc->base, &allocator_impl);
+	wlr_allocator_init(&alloc->base, &allocator_impl, WLR_BUFFER_CAP_DMABUF);
 
 	alloc->fd = fd;
 	wl_list_init(&alloc->buffers);

render/shm_allocator.c

@@ -7,6 +7,7 @@
 #include "render/pixel_format.h"
 #include "render/shm_allocator.h"
 #include "util/shm.h"
+#include "types/wlr_buffer.h"
 
 static const struct wlr_buffer_impl buffer_impl;
 
@@ -30,7 +31,7 @@ static bool buffer_get_shm(struct wlr_buffer *wlr_buffer,
 	return true;
 }
 
-static bool buffer_get_data_ptr(struct wlr_buffer *wlr_buffer, void **data,
+static bool shm_buffer_get_data_ptr(struct wlr_buffer *wlr_buffer, void **data,
 		uint32_t *format, size_t *stride) {
 	struct wlr_shm_buffer *buffer = shm_buffer_from_buffer(wlr_buffer);
 	*data = buffer->data;
@@ -42,7 +43,7 @@ static bool buffer_get_data_ptr(struct wlr_buffer *wlr_buffer, void **data,
 static const struct wlr_buffer_impl buffer_impl = {
 	.destroy = buffer_destroy,
 	.get_shm = buffer_get_shm,
-	.get_data_ptr = buffer_get_data_ptr,
+	.get_data_ptr = shm_buffer_get_data_ptr,
 };
 
 static struct wlr_buffer *allocator_create_buffer(
@@ -103,7 +104,8 @@ struct wlr_allocator *wlr_shm_allocator_create(void) {
 	if (allocator == NULL) {
 		return NULL;
 	}
-	wlr_allocator_init(&allocator->base, &allocator_impl);
+	wlr_allocator_init(&allocator->base, &allocator_impl,
+		WLR_BUFFER_CAP_DATA_PTR | WLR_BUFFER_CAP_SHM);
 
 	wlr_log(WLR_DEBUG, "Created shm allocator");
 	return &allocator->base;