Add wayland backend cursor support

backend/meson.build

@@ -22,6 +22,7 @@ backend_files = files(
   'wayland/output.c',
   'wayland/registry.c',
   'wayland/wl_seat.c',
+  'wayland/os-compatibility.c',
 )
 
 if systemd.found()

backend/wayland/os-compatibility.c

@@ -0,0 +1,154 @@
+/*
+ * Copyright © 2012 Collabora, Ltd.
+ *
+ * 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 (including the
+ * next paragraph) 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.
+ */
+
+#define _XOPEN_SOURCE 700
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/epoll.h>
+#include <string.h>
+#include <stdlib.h>
+
+int
+os_fd_set_cloexec(int fd)
+{
+	long flags;
+
+	if (fd == -1)
+		return -1;
+
+	flags = fcntl(fd, F_GETFD);
+	if (flags == -1)
+		return -1;
+
+	if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)
+		return -1;
+
+	return 0;
+}
+
+static int
+set_cloexec_or_close(int fd)
+{
+	if (os_fd_set_cloexec(fd) != 0) {
+		close(fd);
+		return -1;
+	}
+	return fd;
+}
+
+static int
+create_tmpfile_cloexec(char *tmpname)
+{
+	int fd;
+
+#ifdef HAVE_MKOSTEMP
+	fd = mkostemp(tmpname, O_CLOEXEC);
+	if (fd >= 0)
+		unlink(tmpname);
+#else
+	fd = mkstemp(tmpname);
+	if (fd >= 0) {
+		fd = set_cloexec_or_close(fd);
+		unlink(tmpname);
+	}
+#endif
+
+	return fd;
+}
+
+/*
+ * Create a new, unique, anonymous file of the given size, and
+ * return the file descriptor for it. The file descriptor is set
+ * CLOEXEC. The file is immediately suitable for mmap()'ing
+ * the given size at offset zero.
+ *
+ * The file should not have a permanent backing store like a disk,
+ * but may have if XDG_RUNTIME_DIR is not properly implemented in OS.
+ *
+ * The file name is deleted from the file system.
+ *
+ * The file is suitable for buffer sharing between processes by
+ * transmitting the file descriptor over Unix sockets using the
+ * SCM_RIGHTS methods.
+ *
+ * If the C library implements posix_fallocate(), it is used to
+ * guarantee that disk space is available for the file at the
+ * given size. If disk space is insufficient, errno is set to ENOSPC.
+ * If posix_fallocate() is not supported, program may receive
+ * SIGBUS on accessing mmap()'ed file contents instead.
+ */
+int
+os_create_anonymous_file(off_t size)
+{
+	static const char template[] = "/wlroots-shared-XXXXXX";
+	const char *path;
+	char *name;
+	int fd;
+	int ret;
+
+	path = getenv("XDG_RUNTIME_DIR");
+	if (!path) {
+		errno = ENOENT;
+		return -1;
+	}
+
+	name = malloc(strlen(path) + sizeof(template));
+	if (!name)
+		return -1;
+
+	strcpy(name, path);
+	strcat(name, template);
+
+	fd = create_tmpfile_cloexec(name);
+
+	free(name);
+
+	if (fd < 0)
+		return -1;
+
+#ifdef HAVE_POSIX_FALLOCATE
+	do {
+		ret = posix_fallocate(fd, 0, size);
+	} while (ret == EINTR);
+	if (ret != 0) {
+		close(fd);
+		errno = ret;
+		return -1;
+	}
+#else
+	do {
+		ret = ftruncate(fd, size);
+	} while (ret < 0 && errno == EINTR);
+	if (ret < 0) {
+		close(fd);
+		return -1;
+	}
+#endif
+
+	return fd;
+}

backend/wayland/output.c

@@ -3,12 +3,17 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/mman.h>
 #include <wayland-client.h>
 #include <GLES3/gl3.h>
 #include <wlr/interfaces/wlr_output.h>
 #include <wlr/util/log.h>
 #include "backend/wayland.h"
 
+int os_create_anonymous_file(off_t size);
+
 static struct wl_callback_listener frame_listener;
 
 static void surface_frame_callback(void *data, struct wl_callback *cb, uint32_t time) {
@@ -46,9 +51,86 @@ static void wlr_wl_output_transform(struct wlr_output *_output,
 	output->wlr_output.transform = transform;
 }
 
+static bool wlr_wl_output_set_cursor(struct wlr_output *_output,
+		const uint8_t *buf, int32_t stride, uint32_t width, uint32_t height) {
+
+	struct wlr_wl_backend_output *output = (struct wlr_wl_backend_output *)_output;
+	struct wlr_wl_backend *backend = output->backend;
+	stride *= 4; // stride is given in pixels, we need it in bytes
+
+	if (!backend->shm || !backend->pointer) {
+		wlr_log(L_INFO, "cannot set cursor, no shm or pointer");
+		return false;
+	}
+
+	if (!output->cursor_surface) {
+		output->cursor_surface = wl_compositor_create_surface(output->backend->compositor);
+	}
+
+	uint32_t size = stride * height;
+	if (output->cursor_buf_size != size) {
+		if (output->cursor_buffer) {
+			wl_buffer_destroy(output->cursor_buffer);
+		}
+
+		if (size > output->cursor_buf_size) {
+			if (output->cursor_pool) {
+				wl_shm_pool_destroy(output->cursor_pool);
+				output->cursor_pool = NULL;
+				munmap(output->cursor_data, output->cursor_buf_size);
+			}
+		}
+
+		if (!output->cursor_pool) {
+			int fd = os_create_anonymous_file(size);
+			if (fd < 0) {
+				wlr_log_errno(L_INFO, "creating anonymous file for cursor buffer failed");
+				return false;
+			}
+
+			output->cursor_data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+			if (output->cursor_data == MAP_FAILED) {
+				close(fd);
+				wlr_log_errno(L_INFO, "mmap failed");
+				return false;
+			}
+
+			output->cursor_pool = wl_shm_create_pool(backend->shm, fd, size);
+			close(fd);
+		}
+
+		output->cursor_buffer = wl_shm_pool_create_buffer(output->cursor_pool,
+			0, width, height, stride, WL_SHM_FORMAT_ARGB8888);
+		output->cursor_buf_size = size;
+	}
+
+	memcpy(output->cursor_data, buf, size);
+	wl_surface_attach(output->cursor_surface, output->cursor_buffer, 0, 0);
+	wl_surface_damage(output->cursor_surface, 0, 0, width, height);
+	wl_surface_commit(output->cursor_surface);
+
+	wlr_wl_output_update_cursor(output, output->enter_serial);
+	return true;
+}
+
 static void wlr_wl_output_destroy(struct wlr_output *_output) {
 	struct wlr_wl_backend_output *output = (struct wlr_wl_backend_output *)_output;
 	wl_signal_emit(&output->backend->backend.events.output_remove, &output->wlr_output);
+
+	if (output->cursor_buf_size != 0) {
+		assert(output->cursor_data);
+		assert(output->cursor_buffer);
+		assert(output->cursor_pool);
+
+		wl_buffer_destroy(output->cursor_buffer);
+		munmap(output->cursor_data, output->cursor_buf_size);
+		wl_shm_pool_destroy(output->cursor_pool);
+	}
+
+	if (output->cursor_surface) {
+		wl_surface_destroy(output->cursor_surface);
+	}
+
 	if (output->frame_callback) {
 		wl_callback_destroy(output->frame_callback);
 	}
@@ -59,11 +141,25 @@ static void wlr_wl_output_destroy(struct wlr_output *_output) {
 	free(output);
 }
 
+void wlr_wl_output_update_cursor(struct wlr_wl_backend_output *output, uint32_t serial) {
+	if (output->cursor_surface && output->backend->pointer && serial) {
+		wl_pointer_set_cursor(output->backend->pointer, serial,
+			output->cursor_surface, 0, 0);
+	}
+}
+
+bool wlr_wl_output_move_cursor(struct wlr_output *_output, int x, int y) {
+	// TODO: only return true if x == current x and y == current y
+	return true;
+}
+
 static struct wlr_output_impl output_impl = {
 	.transform = wlr_wl_output_transform,
 	.destroy = wlr_wl_output_destroy,
 	.make_current = wlr_wl_output_make_current,
 	.swap_buffers = wlr_wl_output_swap_buffers,
+	.set_cursor = wlr_wl_output_set_cursor,
+	.move_cursor = wlr_wl_output_move_cursor
 };
 
 void handle_ping(void* data, struct wl_shell_surface* ssurface, uint32_t serial) {

backend/wayland/wl_seat.c

@@ -23,6 +23,8 @@ static void pointer_handle_enter(void *data, struct wl_pointer *wl_pointer,
 		wlr_wl_output_for_surface(wlr_wl_dev->backend, surface);
 	assert(output);
 	wlr_wl_pointer->current_output = output;
+	wlr_wl_pointer->current_output->enter_serial = serial;
+	wlr_wl_output_update_cursor(wlr_wl_pointer->current_output, serial);
 }
 
 static void pointer_handle_leave(void *data, struct wl_pointer *wl_pointer,
@@ -30,8 +32,11 @@ static void pointer_handle_leave(void *data, struct wl_pointer *wl_pointer,
 	struct wlr_input_device *dev = data;
 	assert(dev && dev->pointer);
 	struct wlr_wl_pointer *wlr_wl_pointer = (struct wlr_wl_pointer *)dev->pointer;
+	if (wlr_wl_pointer->current_output) {
+		wlr_wl_pointer->current_output->enter_serial = 0;
 		wlr_wl_pointer->current_output = NULL;
 	}
+}
 
 static void pointer_handle_motion(void *data, struct wl_pointer *wl_pointer,
 		uint32_t time, wl_fixed_t surface_x, wl_fixed_t surface_y) {
@@ -227,6 +232,7 @@ static void seat_handle_capabilities(void *data, struct wl_seat *wl_seat,
 		wlr_pointer_init(wlr_device->pointer, NULL);
 		wlr_wl_device->resource = wl_pointer;
 		wl_signal_emit(&backend->backend.events.input_add, wlr_device);
+		backend->pointer = wl_pointer;
 	}
 	if ((caps & WL_SEAT_CAPABILITY_KEYBOARD)) {
 		wlr_log(L_DEBUG, "seat %p offered keyboard", (void*) wl_seat);

include/backend/wayland.h

@@ -27,6 +27,7 @@ struct wlr_wl_backend {
 	struct wl_shell *shell;
 	struct wl_shm *shm;
 	struct wl_seat *seat;
+	struct wl_pointer *pointer;
 	char *seat_name;
 };
 
@@ -38,6 +39,14 @@ struct wlr_wl_backend_output {
 	struct wl_shell_surface *shell_surface;
 	struct wl_egl_window *egl_window;
 	struct wl_callback *frame_callback;
+
+	struct wl_shm_pool *cursor_pool;
+	void *cursor_buffer; // actually a (client-side) struct wl_buffer*
+	uint8_t *cursor_data;
+	struct wl_surface *cursor_surface;
+	uint32_t cursor_buf_size;
+	uint32_t enter_serial;
+
 	void *egl_surface;
 };
 
@@ -55,6 +64,7 @@ struct wlr_wl_pointer {
 };
 
 void wlr_wl_registry_poll(struct wlr_wl_backend *backend);
+void wlr_wl_output_update_cursor(struct wlr_wl_backend_output *output, uint32_t serial);
 struct wlr_wl_backend_output *wlr_wl_output_for_surface(
 		struct wlr_wl_backend *backend, struct wl_surface *surface);