initial commit

yup, i definitely wrote all of this in a single commit

1 files changed, 391 insertions, 0 deletions

diff --git a/src/services/brightness-service.c b/src/services/brightness-service.c
new file mode 100644
index 0000000..32f0501
--- /dev/null
+++ b/src/services/brightness-service.c
@@ -0,0 +1,391 @@
+#include "services/brightness-service.h"
+#include <gio/gio.h>
+#include <math.h>
+
+//
+// FoobarBrightnessService:
+//
+// Service managing the brightness level. This is implemented by
+// - for read access: monitoring the "brightness" file in a "/sys/class/backlight" subdirectory,
+// - for write access: invoking the "brightnessctl" command.
+//
+
+struct _FoobarBrightnessService
+{
+	GObject       parent_instance;
+	gint          percentage;
+	GFileMonitor* file_monitor;
+	gulong        file_monitor_handler_id;
+	gchar*        device_name;
+	gchar*        file_path;
+	gint          max_brightness;
+};
+
+enum
+{
+	PROP_PERCENTAGE = 1,
+	N_PROPS,
+};
+
+static GParamSpec* props[N_PROPS] = { 0 };
+
+static void          foobar_brightness_service_class_init               ( FoobarBrightnessServiceClass* klass );
+static void          foobar_brightness_service_init                     ( FoobarBrightnessService*      self );
+static void          foobar_brightness_service_get_property             ( GObject*                      object,
+                                                                          guint                         prop_id,
+                                                                          GValue*                       value,
+                                                                          GParamSpec*                   pspec );
+static void          foobar_brightness_service_set_property             ( GObject*                      object,
+                                                                          guint                         prop_id,
+                                                                          GValue const*                 value,
+                                                                          GParamSpec*                   pspec );
+static void          foobar_brightness_service_finalize                 ( GObject*                      object );
+static void          foobar_brightness_service_handle_changed           ( GFileMonitor*                 monitor,
+                                                                          GFile*                        file,
+                                                                          GFile*                        other_file,
+                                                                          GFileMonitorEvent             event_type,
+                                                                          gpointer                      userdata );
+static gint          foobar_brightness_service_load_percentage          ( FoobarBrightnessService*      self );
+static void          foobar_brightness_service_write_percentage         ( FoobarBrightnessService*      self );
+static void          foobar_brightness_service_write_percentage_watch_cb( GPid                          pid,
+                                                                          gint                          status,
+                                                                          gpointer                      userdata );
+static void          foobar_brightness_service_get_info                 ( gchar**                       out_device_name,
+                                                                          gchar**                       out_file_path,
+                                                                          gint*                         out_max_brightness );
+static gint          foobar_brightness_service_read_value               ( gchar const*                  path );
+static GFileMonitor* foobar_brightness_service_monitor                  ( gchar const*                  path );
+
+G_DEFINE_FINAL_TYPE( FoobarBrightnessService, foobar_brightness_service, G_TYPE_OBJECT )
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Service Implementation
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Static initialization for the brightness service.
+//
+void foobar_brightness_service_class_init( FoobarBrightnessServiceClass* klass )
+{
+	GObjectClass* object_klass = G_OBJECT_CLASS( klass );
+	object_klass->get_property = foobar_brightness_service_get_property;
+	object_klass->set_property = foobar_brightness_service_set_property;
+	object_klass->finalize = foobar_brightness_service_finalize;
+
+	props[PROP_PERCENTAGE] = g_param_spec_int(
+		"percentage",
+		"Percentage",
+		"Current brightness percentage.",
+		0,
+		100,
+		100,
+		G_PARAM_READWRITE );
+	g_object_class_install_properties( object_klass, N_PROPS, props );
+}
+
+//
+// Instance initialization for the brightness service.
+//
+void foobar_brightness_service_init( FoobarBrightnessService* self )
+{
+	foobar_brightness_service_get_info( &self->device_name, &self->file_path, &self->max_brightness );
+	self->percentage = foobar_brightness_service_load_percentage( self );
+	if ( self->file_path )
+	{
+		self->file_monitor = foobar_brightness_service_monitor( self->file_path );
+	}
+	if ( self->file_monitor )
+	{
+		self->file_monitor_handler_id = g_signal_connect(
+			self->file_monitor,
+			"changed",
+			G_CALLBACK( foobar_brightness_service_handle_changed ),
+			self );
+	}
+	else
+	{
+		self->file_monitor_handler_id = 0;
+	}
+}
+
+//
+// Property getter implementation, mapping a property id to a method.
+//
+void foobar_brightness_service_get_property(
+	GObject*    object,
+	guint       prop_id,
+	GValue*     value,
+	GParamSpec* pspec )
+{
+	FoobarBrightnessService* self = (FoobarBrightnessService*)object;
+
+	switch ( prop_id )
+	{
+		case PROP_PERCENTAGE:
+			g_value_set_int( value, foobar_brightness_service_get_percentage( self ) );
+			break;
+		default:
+			G_OBJECT_WARN_INVALID_PROPERTY_ID( object, prop_id, pspec );
+			break;
+	}
+}
+
+//
+// Property setter implementation, mapping a property id to a method.
+//
+void foobar_brightness_service_set_property(
+	GObject*      object,
+	guint         prop_id,
+	GValue const* value,
+	GParamSpec*   pspec )
+{
+	FoobarBrightnessService* self = (FoobarBrightnessService*)object;
+
+	switch ( prop_id )
+	{
+		case PROP_PERCENTAGE:
+			foobar_brightness_service_set_percentage( self, g_value_get_int( value ) );
+			break;
+		default:
+			G_OBJECT_WARN_INVALID_PROPERTY_ID( object, prop_id, pspec );
+			break;
+	}
+}
+
+//
+// Instance cleanup for the brightness service.
+//
+void foobar_brightness_service_finalize( GObject* object )
+{
+	FoobarBrightnessService* self = (FoobarBrightnessService*)object;
+
+	g_clear_signal_handler( &self->file_monitor_handler_id, self->file_monitor );
+	g_clear_object( &self->file_monitor );
+	g_clear_pointer( &self->device_name, g_free );
+	g_clear_pointer( &self->file_path, g_free );
+
+	G_OBJECT_CLASS( foobar_brightness_service_parent_class )->finalize( object );
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Public API
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Create a new brightness service instance.
+//
+FoobarBrightnessService* foobar_brightness_service_new( void )
+{
+	return g_object_new( FOOBAR_TYPE_BRIGHTNESS_SERVICE, NULL );
+}
+
+//
+// Get the current brightness percentage value.
+//
+gint foobar_brightness_service_get_percentage( FoobarBrightnessService* self )
+{
+	g_return_val_if_fail( FOOBAR_IS_BRIGHTNESS_SERVICE( self ), 0 );
+
+	return self->percentage;
+}
+
+//
+// Update the current brightness percentage value.
+//
+void foobar_brightness_service_set_percentage(
+	FoobarBrightnessService* self,
+	gint                     value )
+{
+	g_return_if_fail( FOOBAR_IS_BRIGHTNESS_SERVICE( self ) );
+
+	value = CLAMP( value, 0, 100 );
+	if ( self->percentage != value )
+	{
+		self->percentage = value;
+		g_object_notify_by_pspec( G_OBJECT( self ), props[PROP_PERCENTAGE] );
+		foobar_brightness_service_write_percentage( self );
+	}
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Signal Handlers
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Called by the file monitor when the contents of the "brightness" file have changed.
+//
+void foobar_brightness_service_handle_changed(
+	GFileMonitor*     monitor,
+	GFile*            file,
+	GFile*            other_file,
+	GFileMonitorEvent event_type,
+	gpointer          userdata )
+{
+	(void)monitor;
+	(void)file;
+	(void)other_file;
+	(void)event_type;
+	FoobarBrightnessService* self = (FoobarBrightnessService*)userdata;
+
+	gint new_percentage = foobar_brightness_service_load_percentage( self );
+	if ( self->percentage != new_percentage )
+	{
+		self->percentage = new_percentage;
+		g_object_notify_by_pspec( G_OBJECT( self ), props[PROP_PERCENTAGE] );
+	}
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Helper Methods
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Load the current percentage value from the file at self->file_path.
+//
+// This requires file_path and max_brightness to be initialized, otherwise the brightness is assumed to be 100%.
+//
+gint foobar_brightness_service_load_percentage( FoobarBrightnessService* self )
+{
+	if ( !self->file_path || self->max_brightness == -1 ) { return 100; }
+
+	gint value = foobar_brightness_service_read_value( self->file_path );
+	if ( value == -1 ) { return 100; }
+
+	gdouble rel = value / (gdouble)self->max_brightness;
+	gint percentage = (gint)round( rel * 100. );
+	return CLAMP( percentage, 0, 100 );
+}
+
+//
+// Asynchronously update the current percentage value by invoking brightnessctl.
+//
+// This requires device_name to be initialized.
+//
+void foobar_brightness_service_write_percentage( FoobarBrightnessService* self )
+{
+	if ( !self->device_name ) { return; }
+
+	g_autofree gchar* percentage_string = g_strdup_printf( "%d%%", self->percentage );
+	gchar* args[] = { "brightnessctl", "-d", self->device_name, "s", percentage_string, NULL };
+
+	g_autoptr( GError ) error = NULL;
+	GPid child_pid;
+	if ( !g_spawn_async(
+		NULL,
+		args,
+		NULL,
+		G_SPAWN_DO_NOT_REAP_CHILD
+			| G_SPAWN_SEARCH_PATH
+			| G_SPAWN_STDIN_FROM_DEV_NULL
+			| G_SPAWN_STDOUT_TO_DEV_NULL
+			| G_SPAWN_STDERR_TO_DEV_NULL,
+		NULL,
+		NULL,
+		&child_pid,
+		&error ) )
+	{
+		g_warning( "Unable to spawn brightnessctl: %s", error->message );
+		return;
+	}
+
+	g_child_watch_add( child_pid, foobar_brightness_service_write_percentage_watch_cb, NULL );
+}
+
+//
+// Called when the brightnessctl child process has finished.
+//
+void foobar_brightness_service_write_percentage_watch_cb(
+	GPid     pid,
+	gint     status,
+	gpointer userdata )
+{
+	(void)userdata;
+
+	g_autoptr( GError ) error = NULL;
+	if ( !g_spawn_check_wait_status( status, &error ) )
+	{
+		g_warning( "Unable to set brightness with brightnessctl: %s", error->message );
+	}
+
+	g_spawn_close_pid( pid );
+}
+
+//
+// Initialize information for the brightness device.
+//
+// This looks for the first directory in the /sys/class/backlight directories and uses it as the device name. It also
+// populates out_file_path to the path of this directory and out_max_brightness to the contents of the corresponding
+// max_brightness file.
+//
+void foobar_brightness_service_get_info(
+	gchar** out_device_name,
+	gchar** out_file_path,
+	gint*   out_max_brightness )
+{
+	*out_device_name = NULL;
+	*out_file_path = NULL;
+	*out_max_brightness = -1;
+
+	g_autoptr( GFile ) dir = g_file_new_for_path( "/sys/class/backlight" );
+	if ( !dir ) { return; }
+
+	g_autoptr( GFileEnumerator ) enumerator = g_file_enumerate_children(
+		dir,
+		"standard::",
+		G_FILE_QUERY_INFO_NONE,
+		NULL,
+		NULL );
+	if ( !enumerator ) { return; }
+
+	g_autoptr( GFileInfo ) info = g_file_enumerator_next_file( enumerator, NULL, NULL );
+	g_file_enumerator_close( enumerator, NULL, NULL );
+	if ( !info ) { return; }
+
+	gchar* device_name = g_strdup( g_file_info_get_name( info ) );
+	gchar* current_file_path = g_strdup_printf( "/sys/class/backlight/%s/brightness", device_name );
+	gchar* max_file_path = g_strdup_printf( "/sys/class/backlight/%s/max_brightness", device_name );
+	*out_device_name = device_name;
+	*out_file_path = current_file_path;
+	*out_max_brightness = foobar_brightness_service_read_value( max_file_path );
+	g_free( max_file_path );
+}
+
+//
+// Read the current brightness integer (not percentage) from the given file path.
+//
+gint foobar_brightness_service_read_value( gchar const* path )
+{
+	g_autofree gchar* contents = NULL;
+	g_autoptr( GError ) error = NULL;
+	if ( !g_file_get_contents( path, &contents, NULL, &error ) )
+	{
+		g_warning( "Unable to read %s: %s", path, error->message );
+		return -1;
+	}
+
+	errno = 0;
+	char* endptr;
+	long  result = strtol( contents, &endptr, 10 );
+	if ( errno != 0 || endptr == contents || result > INT_MAX || result < 0 )
+	{
+		g_warning( "Expected integer in %s, but got: %s", path, contents );
+		return -1;
+	}
+
+	return (gint)result;
+}
+
+//
+// Set up a file monitor for the given path.
+//
+GFileMonitor* foobar_brightness_service_monitor( gchar const* path )
+{
+	g_autoptr( GFile ) file = g_file_new_for_path( path );
+	if ( !file ) { return NULL; }
+
+	g_autoptr( GError ) error = NULL;
+	GFileMonitor* monitor = g_file_monitor_file( file, G_FILE_MONITOR_NONE, NULL, &error );
+	if ( !monitor ) { g_warning( "Unable to monitor brightness: %s", error->message ); }
+
+	return monitor;
+}