Add buffer.c to cover cairo-surface to wlr_buffer

include/buffer.h

@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Based on wlroots/include/types/wlr_buffer.c
+ *
+ * Copyright (c) 2017, 2018 Drew DeVault
+ * Copyright (c) 2018-2021 Simon Ser, Simon Zeni
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef __LABWC_BUFFER_H
+#define __LABWC_BUFFER_H
+
+#include "labwc.h"
+
+/**
+ * A read-only buffer that holds a data pointer.
+ *
+ * This is suitable for passing raw pixel data to a function that accepts a
+ * wlr_buffer.
+ */
+struct lab_data_buffer {
+	struct wlr_buffer base;
+
+	const void *data;
+	uint32_t format;
+	size_t stride;
+
+	void *saved_data;
+};
+
+/**
+ * Wraps a read-only data pointer into a wlr_buffer. The data pointer may be
+ * accessed until readonly_data_buffer_drop() is called.
+ */
+struct lab_data_buffer *buffer_create(uint32_t format, size_t stride,
+	uint32_t width, uint32_t height, const void *data);
+
+/**
+ * Drops ownership of the buffer (see wlr_buffer_drop() for more details) and
+ * perform a copy of the data pointer if a consumer still has the buffer locked.
+ */
+bool buffer_drop(struct lab_data_buffer *buffer);
+
+#endif /* __LABWC_BUFFER_H */

src/buffer.c

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Based on wlroots/types/wlr_buffer.c
+ *
+ * Copyright (c) 2017, 2018 Drew DeVault
+ * Copyright (c) 2018-2021 Simon Ser, Simon Zeni
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "config.h"
+#include <assert.h>
+#include <drm_fourcc.h>
+#include "buffer.h"
+
+static const struct wlr_buffer_impl data_buffer_impl;
+
+static struct lab_data_buffer *
+data_buffer_from_buffer(struct wlr_buffer *buffer)
+{
+	assert(buffer->impl == &data_buffer_impl);
+	return (struct lab_data_buffer *)buffer;
+}
+
+static void
+data_buffer_destroy(struct wlr_buffer *wlr_buffer)
+{
+	struct lab_data_buffer *buffer = data_buffer_from_buffer(wlr_buffer);
+	free(buffer->saved_data);
+	free(buffer);
+}
+
+static bool
+data_buffer_begin_data_ptr_access(struct wlr_buffer *wlr_buffer, uint32_t flags,
+		void **data, uint32_t *format, size_t *stride)
+{
+	struct lab_data_buffer *buffer = data_buffer_from_buffer(wlr_buffer);
+	if (buffer->data == NULL) {
+		return false;
+	}
+	if (flags & WLR_BUFFER_DATA_PTR_ACCESS_WRITE) {
+		return false;
+	}
+	*data = (void *)buffer->data;
+	*format = buffer->format;
+	*stride = buffer->stride;
+	return true;
+}
+
+static void
+data_buffer_end_data_ptr_access(struct wlr_buffer *wlr_buffer)
+{
+	/* noop */
+}
+
+static const struct wlr_buffer_impl data_buffer_impl = {
+	.destroy = data_buffer_destroy,
+	.begin_data_ptr_access = data_buffer_begin_data_ptr_access,
+	.end_data_ptr_access = data_buffer_end_data_ptr_access,
+};
+
+struct lab_data_buffer *
+buffer_create(uint32_t format, size_t stride, uint32_t width, uint32_t height,
+		const void *data)
+{
+	struct lab_data_buffer *buffer = calloc(1, sizeof(*buffer));
+	if (buffer == NULL) {
+		return NULL;
+	}
+	wlr_buffer_init(&buffer->base, &data_buffer_impl, width, height);
+	buffer->data = data;
+	buffer->format = format;
+	buffer->stride = stride;
+	return buffer;
+}
+
+
+bool
+buffer_drop(struct lab_data_buffer *buffer)
+{
+	bool ok = true;
+
+	if (buffer->base.n_locks > 0) {
+		size_t size = buffer->stride * buffer->base.height;
+		buffer->saved_data = malloc(size);
+		if (!buffer->saved_data) {
+			wlr_log_errno(WLR_ERROR, "allocation failed");
+			ok = false;
+			buffer->data = NULL;
+		} else {
+			memcpy(buffer->saved_data, buffer->data, size);
+			buffer->data = buffer->saved_data;
+		}
+	}
+	wlr_buffer_drop(&buffer->base);
+	return ok;
+}

src/meson.build

@@ -1,5 +1,6 @@
 labwc_sources = files(
   'action.c',
+  'buffer.c',
   'cursor.c',
   'damage.c',
   'desktop.c',