[PATCH weston] clients: Add a weston-autorotater client and rotater protocol

Emmanuel Gil Peyrot emmanuel.peyrot at collabora.com
Sat May 21 02:43:04 UTC 2016


This client uses libiio to retrieve accelerometer values from the iio
subsystem on Linux (and maybe some other kernels), and automatically
rotate the output whenever orientation changed.

I tested it with a mma8453 accelerometer, but everything needed should
be available in the configuration to make it work with any other iio
device.

Signed-off-by: Emmanuel Gil Peyrot <emmanuel.peyrot at collabora.com>
---
 Makefile.am                 |  24 +++
 clients/autorotater.c       | 472 ++++++++++++++++++++++++++++++++++++++++++++
 configure.ac                |  15 ++
 desktop-shell/shell.c       |   1 +
 protocol/weston-rotater.xml |  26 +++
 src/compositor.h            |   3 +
 src/rotater.c               | 150 ++++++++++++++
 7 files changed, 691 insertions(+)
 create mode 100644 clients/autorotater.c
 create mode 100644 protocol/weston-rotater.xml
 create mode 100644 src/rotater.c

diff --git a/Makefile.am b/Makefile.am
index 00b74e5..b1e0ade 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -122,6 +122,8 @@ endif
 nodist_weston_SOURCES =					\
 	protocol/weston-screenshooter-protocol.c			\
 	protocol/weston-screenshooter-server-protocol.h			\
+	protocol/weston-rotater-protocol.c		\
+	protocol/weston-rotater-server-protocol.h	\
 	protocol/text-cursor-position-protocol.c	\
 	protocol/text-cursor-position-server-protocol.h	\
 	protocol/text-input-unstable-v1-protocol.c			\
@@ -611,6 +613,28 @@ nodist_weston_screenshooter_SOURCES =			\
 weston_screenshooter_LDADD = $(CLIENT_LIBS) libshared.la
 weston_screenshooter_CFLAGS = $(AM_CFLAGS) $(CLIENT_CFLAGS)
 
+if BUILD_AUTOROTATER
+libexec_PROGRAMS += weston-autorotater
+
+weston_autorotater_SOURCES =				\
+	clients/autorotater.c
+nodist_weston_autorotater_SOURCES =			\
+	protocol/weston-rotater-protocol.c		\
+	protocol/weston-rotater-client-protocol.h
+weston_autorotater_LDADD = $(CLIENT_LIBS) $(LIBIIO_LIBS) libshared.la
+weston_autorotater_CFLAGS = $(AM_CFLAGS) $(CLIENT_CFLAGS) $(LIBIIO_CFLAGS)
+
+weston_SOURCES +=					\
+	src/rotater.c
+
+BUILT_SOURCES +=					\
+	protocol/weston-rotater-protocol.c		\
+	protocol/weston-rotater-client-protocol.h
+
+EXTRA_DIST +=						\
+	protocol/weston-rotater.xml
+endif
+
 weston_terminal_SOURCES = 				\
 	clients/terminal.c				\
 	shared/helpers.h
diff --git a/clients/autorotater.c b/clients/autorotater.c
new file mode 100644
index 0000000..0547f83
--- /dev/null
+++ b/clients/autorotater.c
@@ -0,0 +1,472 @@
+/*
+ * Copyright © 2016 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.
+ */
+
+#include "config.h"
+
+#include <stdint.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <wayland-client.h>
+#include "weston-rotater-client-protocol.h"
+#include "shared/config-parser.h"
+#include "shared/helpers.h"
+#include "shared/xalloc.h"
+
+#include <iio.h>
+
+#define BUFFER_SIZE 256
+
+static struct weston_rotater *rotater;
+static struct wl_list output_list;
+
+struct rotater_output {
+	struct wl_output *output;
+	struct wl_list link;
+};
+
+#define DEFAULT_SAMPLING_FREQUENCY 100.
+
+struct config {
+	char *device_name;
+	char *channel_x_name, *channel_y_name;
+	char *sampling_frequency_name;
+	double wanted_sampling_frequency;
+	int threshold;
+	int smooth_capture;
+	struct wl_array allowed_rotations;
+};
+
+#define MAX_CAPTURE_BUFFER_LENGTH 16
+
+struct accelerometer {
+	struct iio_context *context;
+	struct iio_device *device;
+	struct iio_channel *channel_x, *channel_y;
+	double sampling_frequency;
+
+	struct {
+		int x[MAX_CAPTURE_BUFFER_LENGTH];
+		int y[MAX_CAPTURE_BUFFER_LENGTH];
+	} capture_buffer;
+};
+
+static const struct {
+	const char *name;
+	int token;
+} transforms[] = {
+	{ "normal",     WESTON_ROTATER_TRANSFORM_NORMAL },
+	{ "90",         WESTON_ROTATER_TRANSFORM_90 },
+	{ "180",        WESTON_ROTATER_TRANSFORM_180 },
+	{ "270",        WESTON_ROTATER_TRANSFORM_270 },
+	{ "flipped",    WESTON_ROTATER_TRANSFORM_FLIPPED },
+	{ "flipped-90", WESTON_ROTATER_TRANSFORM_FLIPPED_90 },
+	{ "flipped-180", WESTON_ROTATER_TRANSFORM_FLIPPED_180 },
+	{ "flipped-270", WESTON_ROTATER_TRANSFORM_FLIPPED_270 },
+};
+
+static bool
+parse_transform(const char *transform, int *out)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_LENGTH(transforms); i++)
+		if (strncmp(transforms[i].name, transform,
+		            strlen(transforms[i].name)) == 0) {
+			*out = transforms[i].token;
+			return true;
+		}
+
+	return false;
+}
+
+static struct config *
+read_configuration(void)
+{
+	struct config *configuration;
+	const char *config_file;
+	struct weston_config *config;
+	struct weston_config_section *s;
+
+	char *allowed_rotations, *p;
+	int transform, *array_items;
+	int i;
+
+	configuration = zalloc(sizeof *configuration);
+	if (!configuration)
+		return NULL;
+
+	config_file = weston_config_get_name_from_env();
+	config = weston_config_parse(config_file);
+	s = weston_config_get_section(config, "autorotater", NULL, NULL);
+	weston_config_section_get_string(s, "device",
+	                                 &configuration->device_name, NULL);
+	weston_config_section_get_string(s, "channel_x",
+	                                 &configuration->channel_x_name, NULL);
+	weston_config_section_get_string(s, "channel_y",
+	                                 &configuration->channel_y_name, NULL);
+	weston_config_section_get_int(s, "threshold",
+	                                 &configuration->threshold, 128);
+	weston_config_section_get_string(s, "sampling_frequency_attr",
+	                                 &configuration->sampling_frequency_name,
+	                                 NULL);
+	weston_config_section_get_double(s, "wanted_sampling_frequency",
+	                                 &configuration->wanted_sampling_frequency,
+	                                 0.);
+	weston_config_section_get_int(s, "smooth_capture",
+	                              &configuration->smooth_capture, 1);
+	weston_config_section_get_string(s, "allowed_rotations",
+	                                 &allowed_rotations, NULL);
+	weston_config_destroy(config);
+
+	if (configuration->smooth_capture < 1)
+		configuration->smooth_capture = 1;
+	else if (configuration->smooth_capture > MAX_CAPTURE_BUFFER_LENGTH)
+		configuration->smooth_capture = MAX_CAPTURE_BUFFER_LENGTH;
+
+	wl_array_init(&configuration->allowed_rotations);
+	if (allowed_rotations) {
+		p = allowed_rotations;
+		for (i = 0; i < 4; ++i) {
+			if (!parse_transform(p, &transform))
+				break;
+			array_items = wl_array_add(&configuration->allowed_rotations,
+			                          sizeof(int));
+			*array_items = transform;
+			for (; *p != ' ' && *p != '\0'; p++);
+			if (*p++ == '\0')
+				break;
+		}
+		free(allowed_rotations);
+	} else {
+		array_items = wl_array_add(&configuration->allowed_rotations,
+		                           sizeof(int));
+		array_items[0] = WESTON_ROTATER_TRANSFORM_NORMAL;
+		array_items[1] = WESTON_ROTATER_TRANSFORM_90;
+		array_items[2] = WESTON_ROTATER_TRANSFORM_180;
+		array_items[3] = WESTON_ROTATER_TRANSFORM_270;
+	}
+
+	return configuration;
+}
+
+static void
+destroy_configuration(struct config *config)
+{
+	free(config->device_name);
+	free(config->channel_x_name);
+	free(config->channel_y_name);
+	free(config->sampling_frequency_name);
+	wl_array_release(&config->allowed_rotations);
+	free(config);
+}
+
+static struct accelerometer *
+initialize_iio(struct config *config)
+{
+	struct accelerometer *accel;
+	int ret;
+
+	accel = zalloc(sizeof *accel);
+	if (!accel)
+		return NULL;
+
+	accel->context = iio_create_local_context();
+	if (!accel->context)
+		goto err_context;
+
+	if (config->device_name)
+		accel->device = iio_context_find_device(accel->context,
+		                                        config->device_name);
+
+	if (!accel->device) {
+		fprintf(stderr, "couldn't find device %s\n",
+		        config->device_name);
+		goto err_device;
+	}
+
+	accel->channel_x = iio_device_find_channel(accel->device,
+	                                           config->channel_x_name,
+	                                           false);
+	if (!accel->channel_x) {
+		fprintf(stderr, "couldn't find x channel %s\n",
+		        config->channel_x_name);
+		goto err_channel;
+	}
+
+	accel->channel_y = iio_device_find_channel(accel->device,
+	                                           config->channel_y_name,
+	                                           false);
+	if (!accel->channel_y) {
+		fprintf(stderr, "couldn't find y channel %s\n",
+		        config->channel_y_name);
+		goto err_channel;
+	}
+
+	if (config->wanted_sampling_frequency) {
+		ret = iio_device_attr_write_double(accel->device,
+		                                   config->sampling_frequency_name,
+		                                   config->wanted_sampling_frequency);
+		if (ret < 0) {
+			fprintf(stderr, "couldn't set sampling frequency to "
+			                "%f\n",
+			        config->wanted_sampling_frequency);
+			goto err_channel;
+		}
+	}
+
+	ret = iio_device_attr_read_double(accel->device,
+	                                  config->sampling_frequency_name,
+	                                  &accel->sampling_frequency);
+	if (ret < 0) {
+		fprintf(stderr, "couldn't retrieve sampling frequency, "
+		                "defaulting to %f\n",
+		        DEFAULT_SAMPLING_FREQUENCY);
+		accel->sampling_frequency = DEFAULT_SAMPLING_FREQUENCY;
+	}
+
+	return accel;
+
+err_channel:
+err_device:
+	iio_context_destroy(accel->context);
+err_context:
+	free(accel);
+	return NULL;
+}
+
+static void
+destroy_accelerometer(struct accelerometer *accel)
+{
+	if (accel->context)
+		iio_context_destroy(accel->context);
+	free(accel);
+}
+
+static bool
+capture_rotation(struct accelerometer *accel, int pos)
+{
+	char buf[BUFFER_SIZE];
+	ssize_t ret;
+
+	ret = iio_channel_attr_read(accel->channel_x, "raw", buf, BUFFER_SIZE);
+	if (ret < 0) {
+		iio_strerror(-ret, buf, BUFFER_SIZE);
+		fprintf(stderr, "%s\n", buf);
+		return false;
+	}
+	accel->capture_buffer.x[pos] = atoi(buf);
+
+	ret = iio_channel_attr_read(accel->channel_y, "raw", buf, BUFFER_SIZE);
+	if (ret < 0) {
+		iio_strerror(-ret, buf, BUFFER_SIZE);
+		fprintf(stderr, "%s\n", buf);
+		return false;
+	}
+	accel->capture_buffer.y[pos] = atoi(buf);
+	return true;
+}
+
+static void
+smooth_input(struct accelerometer *accel, int pos, int values_count, int *x, int *y)
+{
+	int i;
+
+	*x = accel->capture_buffer.x[pos];
+	*y = accel->capture_buffer.y[pos];
+
+	if (values_count > 1) {
+		for (i = 1; i < values_count; ++i) {
+			*x += accel->capture_buffer.x[(pos - i) % values_count];
+			*y += accel->capture_buffer.y[(pos - i) % values_count];
+		}
+
+		*x /= values_count;
+		*y /= values_count;
+	}
+}
+
+static int
+get_transform(int x, int y, int threshold)
+{
+	if (y > threshold && y > x)
+		return WESTON_ROTATER_TRANSFORM_NORMAL;
+	if (x > threshold && x > y)
+		return WESTON_ROTATER_TRANSFORM_90;
+	if (y < -threshold && y < x)
+		return WESTON_ROTATER_TRANSFORM_180;
+	if (x < -threshold && x < y)
+		return WESTON_ROTATER_TRANSFORM_270;
+	return -1;
+}
+
+static bool
+synchronize(struct wl_display *display, int sampling_frequency)
+{
+	if (wl_display_roundtrip(display) < 0) {
+		fprintf(stderr, "lost connection, aborting\n");
+		return false;
+	}
+	usleep(1000 * sampling_frequency);
+	return true;
+}
+
+static void
+handle_global(void *data, struct wl_registry *registry,
+              uint32_t name, const char *interface, uint32_t version)
+{
+	static struct rotater_output *output;
+
+	if (strcmp(interface, "wl_output") == 0) {
+		output = xmalloc(sizeof *output);
+		output->output = wl_registry_bind(registry, name,
+		                                  &wl_output_interface, 1);
+		wl_list_insert(&output_list, &output->link);
+	} else if (strcmp(interface, "weston_rotater") == 0) {
+		rotater = wl_registry_bind(registry, name,
+		                           &weston_rotater_interface,
+		                           1);
+	}
+}
+
+static void
+handle_global_remove(void *data, struct wl_registry *registry, uint32_t name)
+{
+	/* XXX: unimplemented */
+}
+
+static const struct wl_registry_listener registry_listener = {
+	handle_global,
+	handle_global_remove
+};
+
+int main(int argc, char *argv[])
+{
+	struct wl_display *display;
+	struct wl_registry *registry;
+	struct rotater_output *output;
+	struct config *config;
+	struct accelerometer *accel;
+	bool ret, found;
+	int frame = 0;
+	int x, y;
+	int transform, previous_transform, *allowed_transform;
+
+	if (getenv("WAYLAND_SOCKET") == NULL) {
+		fprintf(stderr, "%s must be launched by weston.\n",
+		        program_invocation_short_name);
+		return 1;
+	}
+
+	display = wl_display_connect(NULL);
+	if (display == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return 2;
+	}
+
+	wl_list_init(&output_list);
+	registry = wl_display_get_registry(display);
+	wl_registry_add_listener(registry, &registry_listener, NULL);
+	wl_display_dispatch(display);
+	wl_display_roundtrip(display);
+	if (rotater == NULL) {
+		fprintf(stderr, "display doesn't support rotater\n");
+		free(registry);
+		wl_display_disconnect(display);
+		return 3;
+	}
+
+	config = read_configuration();
+	if (!config) {
+		fprintf(stderr, "failed to read configuration\n");
+		free(registry);
+		wl_display_disconnect(display);
+		return 4;
+	}
+
+	accel = initialize_iio(config);
+	if (!accel) {
+		fprintf(stderr, "failed to initialize iio subsystem\n");
+		free(registry);
+		wl_display_disconnect(display);
+		destroy_configuration(config);
+		return 5;
+	}
+
+	previous_transform = WESTON_ROTATER_TRANSFORM_NORMAL;
+	for (;;) {
+		ret = capture_rotation(accel, frame);
+		if (!ret) {
+			fprintf(stderr, "failed to capture accelerometer "
+			                "values\n");
+			break;
+		}
+
+		smooth_input(accel, frame, config->smooth_capture, &x, &y);
+
+		transform = get_transform(x, y, config->threshold);
+		if (transform < 0) {
+			if (!synchronize(display, accel->sampling_frequency))
+				return 6;
+			continue;
+		}
+
+		found = false;
+		wl_array_for_each(allowed_transform,
+		                  &config->allowed_rotations) {
+			if (transform == *allowed_transform) {
+				found = true;
+				break;
+			}
+		}
+
+		if (!found) {
+			if (!synchronize(display, accel->sampling_frequency))
+				return 6;
+			continue;
+		}
+
+		if (transform != previous_transform) {
+			wl_list_for_each(output, &output_list, link) {
+				weston_rotater_rotate(rotater,
+				                      output->output,
+				                      transform);
+			}
+		}
+		previous_transform = transform;
+		frame = (frame + 1) % config->smooth_capture;
+
+		if (!synchronize(display, accel->sampling_frequency))
+			return 6;
+	}
+
+	wl_display_disconnect(display);
+	destroy_accelerometer(accel);
+	destroy_configuration(config);
+
+	return 0;
+}
diff --git a/configure.ac b/configure.ac
index e1300b4..61f9eba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -384,6 +384,20 @@ if ! test "x$enable_simple_dmabuf_v4l_client" = "xno"; then
 fi
 AM_CONDITIONAL(BUILD_SIMPLE_DMABUF_V4L_CLIENT, test "x$enable_simple_dmabuf_v4l_client" = "xyes")
 
+AC_ARG_ENABLE(weston-autorotater,
+              AS_HELP_STRING([--disable-weston-autorotater],
+                             [do not build the autorotater client]),,
+              enable_autorotater="auto")
+if ! test "x$enable_autorotater" = "xno"; then
+  PKG_CHECK_MODULES(LIBIIO, [libiio],
+		    have_autorotater=yes, have_autorotater=no)
+  if test "x$have_autorotater" = "xno" -a "x$enable_autorotater" = "xyes"; then
+    AC_MSG_ERROR([autorotater client explicitly enabled, but libiio couldn't be found])
+  fi
+  enable_autorotater="$have_autorotater"
+fi
+AM_CONDITIONAL(BUILD_AUTOROTATER, test "x$enable_autorotater" = "xyes")
+
 AC_ARG_ENABLE(clients, [  --enable-clients],, enable_clients=yes)
 AM_CONDITIONAL(BUILD_CLIENTS, test x$enable_clients = xyes)
 if test x$enable_clients = xyes; then
@@ -688,6 +702,7 @@ AC_MSG_RESULT([
 	Build EGL Clients		${have_cairo_egl}
 	Build Simple Clients		${enable_simple_clients}
 	Build Simple EGL Clients	${enable_simple_egl_clients}
+	Build Autorotater Client	${enable_autorotater}
 
 	Install Demo Clients		${enable_demo_clients_install}
 
diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
index 7d5bca9..c1750a7 100644
--- a/desktop-shell/shell.c
+++ b/desktop-shell/shell.c
@@ -6704,6 +6704,7 @@ module_init(struct weston_compositor *ec,
 	wl_signal_add(&ec->seat_created_signal, &shell->seat_create_listener);
 
 	screenshooter_create(ec);
+	rotater_create(ec);
 
 	shell_add_bindings(ec, shell);
 
diff --git a/protocol/weston-rotater.xml b/protocol/weston-rotater.xml
new file mode 100644
index 0000000..90a6f84
--- /dev/null
+++ b/protocol/weston-rotater.xml
@@ -0,0 +1,26 @@
+<protocol name="weston_rotater">
+
+  <interface name="weston_rotater" version="1">
+
+    <enum name="transform">
+      <description summary="copied from wl_output.transform"/>
+      <entry name="normal" value="0"/>
+      <entry name="90" value="1"/>
+      <entry name="180" value="2"/>
+      <entry name="270" value="3"/>
+      <entry name="flipped" value="4"/>
+      <entry name="flipped_90" value="5"/>
+      <entry name="flipped_180" value="6"/>
+      <entry name="flipped_270" value="7"/>
+    </enum>
+
+    <request name="rotate">
+      <arg name="output" type="object" interface="wl_output"/>
+      <arg name="transform" type="int" enum="transform"/>
+    </request>
+
+    <event name="done"/>
+
+  </interface>
+
+</protocol>
diff --git a/src/compositor.h b/src/compositor.h
index 0bbf458..9a211c1 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -1592,6 +1592,9 @@ int
 weston_screenshooter_shoot(struct weston_output *output, struct weston_buffer *buffer,
 			   weston_screenshooter_done_func_t done, void *data);
 
+void
+rotater_create(struct weston_compositor *ec);
+
 struct clipboard *
 clipboard_create(struct weston_seat *seat);
 
diff --git a/src/rotater.c b/src/rotater.c
new file mode 100644
index 0000000..4575ac7
--- /dev/null
+++ b/src/rotater.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright © 2016 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.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <linux/input-event-codes.h>
+
+#include "compositor.h"
+#include "weston-rotater-server-protocol.h"
+#include "shared/helpers.h"
+
+struct rotater {
+	struct weston_compositor *ec;
+	struct wl_global *global;
+	struct wl_client *client;
+	struct weston_process process;
+	struct wl_listener destroy_listener;
+};
+
+static void
+rotater_rotate(struct wl_client *client,
+               struct wl_resource *resource,
+               struct wl_resource *output_resource,
+               int32_t transform)
+{
+	int32_t current_width;
+	struct weston_output *output =
+		wl_resource_get_user_data(output_resource);
+
+	/* Only swap width and height when the aspect ratio changed. */
+	if ((transform ^ output->transform) & 1) {
+		current_width = output->width;
+		output->width = output->height;
+		output->height = current_width;
+	}
+
+	output->transform = transform;
+	output->dirty = 1;
+	weston_output_damage(output);
+}
+
+struct weston_rotater_interface rotater_implementation = {
+	rotater_rotate
+};
+
+static void
+bind_rotater(struct wl_client *client,
+             void *data, uint32_t version, uint32_t id)
+{
+	struct rotater *rotater = data;
+	struct wl_resource *resource;
+
+	resource = wl_resource_create(client,
+	                              &weston_rotater_interface, 1, id);
+
+	if (client != rotater->client) {
+		wl_resource_post_error(resource,
+		                       WL_DISPLAY_ERROR_INVALID_OBJECT,
+		                       "rotater failed: permission denied");
+		return;
+	}
+
+	wl_resource_set_implementation(resource, &rotater_implementation,
+	                               data, NULL);
+}
+
+static void
+rotater_sigchld(struct weston_process *process, int status)
+{
+	struct rotater *rotater =
+		container_of(process, struct rotater, process);
+
+	rotater->client = NULL;
+}
+
+static void
+rotater_launch_autorotater(struct rotater *rotater)
+{
+	char *rotater_exe;
+	int ret;
+
+	ret = asprintf(&rotater_exe, "%s/%s",
+	               weston_config_get_libexec_dir(),
+	               "/weston-autorotater");
+	if (ret < 0) {
+		weston_log("Could not construct rotater path.\n");
+		return;
+	}
+
+	if (!rotater->client)
+		rotater->client = weston_client_launch(rotater->ec,
+		                        &rotater->process,
+		                        rotater_exe, rotater_sigchld);
+	free(rotater_exe);
+}
+
+static void
+rotater_destroy(struct wl_listener *listener, void *data)
+{
+	struct rotater *rotater =
+		container_of(listener, struct rotater, destroy_listener);
+
+	wl_global_destroy(rotater->global);
+	free(rotater);
+}
+
+WL_EXPORT void
+rotater_create(struct weston_compositor *ec)
+{
+	struct rotater *rotater;
+
+	rotater = malloc(sizeof *rotater);
+	if (rotater == NULL)
+		return;
+
+	rotater->ec = ec;
+	rotater->client = NULL;
+
+	rotater->global = wl_global_create(ec->wl_display,
+	                                   &weston_rotater_interface, 1,
+	                                   rotater, bind_rotater);
+	rotater->destroy_listener.notify = rotater_destroy;
+	wl_signal_add(&ec->destroy_signal, &rotater->destroy_listener);
+	rotater_launch_autorotater(rotater);
+}
-- 
2.8.2



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