implement ext-idle-notify-v1

Makefile

@@ -14,11 +14,15 @@ LIBS=-lrt $\
 	$(shell pkg-config --libs wayland-client) $\
 	$(shell guile-config link)
 OBJ=src/riverguile.o $\
+	src/seat.o src/output.o $\
 	src/call-layout-demand-handler.o $\
 	src/call-user-command-handler.o $\
+	src/call-idle-handler.o $\
 	src/load-script.o $\
-	protocol/river-layout-v3.o
+	protocol/river-layout-v3.o $\
-GEN=protocol/river-layout-v3.c protocol/river-layout-v3.h
+	protocol/ext-idle-notify-v1.o
+GEN=protocol/river-layout-v3.c protocol/river-layout-v3.h $\
+	protocol/ext-idle-notify-v1.c protocol/ext-idle-notify-v1.h
 
 all: riverguile
 

doc/riverguile.1

@@ -59,6 +59,25 @@ The command (string), the currently active tags (integer representing a
 bitfield of size 32) and the global name of the output (integer).
 This event can be used to change paramters of the layout.
 A new layout demand will be send right after this event.
+.P
+The key \fBidle:X\fR installs a handler which is called when the system has been
+idle for \fIX\fR seconds.
+As an example, use \fBidle:300\fR if you wish to be notified of your system
+being idle for five minutes.
+Idle in this case relates to user interaction;
+The system being idle for five minutes usually means there has been no input
+from the user in five minutes.
+Idle status however can also be influenced by other factors, for example by
+other programs inhibiting it (like video players), special sensors (user
+presence sensors) and is generally server-specific policy.
+The handler procedure must accept one argument, a symbol indicating the type
+of idle event.
+This symbol is either \fBidle\fR, indicating the system has been idle for the
+configured amount of time, or \fBresume\fR, indicating that the time intervall
+of the system being idle is over.
+Multiple idle handlers can be installed.
+Note: All idle events relate to the first advetised seat.
+As of now, river only supports a single seat anyway.
 .
 .
 .SH EXAMPLE

protocol/ext-idle-notify-v1.xml

@@ -0,0 +1,102 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="ext_idle_notify_v1">
+  <copyright>
+    Copyright © 2015 Martin Gräßlin
+    Copyright © 2022 Simon Ser
+
+    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.
+  </copyright>
+
+  <interface name="ext_idle_notifier_v1" version="1">
+    <description summary="idle notification manager">
+      This interface allows clients to monitor user idle status.
+
+      After binding to this global, clients can create ext_idle_notification_v1
+      objects to get notified when the user is idle for a given amount of time.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the manager">
+        Destroy the manager object. All objects created via this interface
+        remain valid.
+      </description>
+    </request>
+
+    <request name="get_idle_notification">
+      <description summary="create a notification object">
+        Create a new idle notification object.
+
+        The notification object has a minimum timeout duration and is tied to a
+        seat. The client will be notified if the seat is inactive for at least
+        the provided timeout. See ext_idle_notification_v1 for more details.
+
+        A zero timeout is valid and means the client wants to be notified as
+        soon as possible when the seat is inactive.
+      </description>
+      <arg name="id" type="new_id" interface="ext_idle_notification_v1"/>
+      <arg name="timeout" type="uint" summary="minimum idle timeout in msec"/>
+      <arg name="seat" type="object" interface="wl_seat"/>
+    </request>
+  </interface>
+
+  <interface name="ext_idle_notification_v1" version="1">
+    <description summary="idle notification">
+      This interface is used by the compositor to send idle notification events
+      to clients.
+
+      Initially the notification object is not idle. The notification object
+      becomes idle when no user activity has happened for at least the timeout
+      duration, starting from the creation of the notification object. User
+      activity may include input events or a presence sensor, but is
+      compositor-specific. If an idle inhibitor is active (e.g. another client
+      has created a zwp_idle_inhibitor_v1 on a visible surface), the compositor
+      must not make the notification object idle.
+
+      When the notification object becomes idle, an idled event is sent. When
+      user activity starts again, the notification object stops being idle,
+      a resumed event is sent and the timeout is restarted.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the notification object">
+        Destroy the notification object.
+      </description>
+    </request>
+
+    <event name="idled">
+      <description summary="notification object is idle">
+        This event is sent when the notification object becomes idle.
+
+        It's a compositor protocol error to send this event twice without a
+        resumed event in-between.
+      </description>
+    </event>
+
+    <event name="resumed">
+      <description summary="notification object is no longer idle">
+        This event is sent when the notification object stops being idle.
+
+        It's a compositor protocol error to send this event twice without an
+        idled event in-between. It's a compositor protocol error to send this
+        event prior to any idled event.
+      </description>
+    </event>
+  </interface>
+</protocol>

src/call-idle-handler.c

@@ -0,0 +1,36 @@
+#include <libguile.h>
+
+#include "seat.h"
+#include "call-idle-handler.h"
+
+static void *call_idle_handler_inner (void *data)
+{
+	struct Call_idle_handler_parameters *params =
+		(struct Call_idle_handler_parameters *)data;
+
+	SCM event;
+	switch (params->event)
+	{
+		case IDLE:   event = scm_from_utf8_symbol("idle");   break;
+		case RESUME: event = scm_from_utf8_symbol("resume"); break;
+	}
+
+	return scm_call_1(params->idle->handler, event);
+}
+
+void *call_idle_handler (void *data)
+{
+	/* Continuation barrier causes stack unwind on exceptions (i.e. errors
+	 * in the user defined ide handler) to stop here. Otherwise the entire
+         * stack created by scm_with_guile() would be unwound. This makes
+         * responding to exceptions nicer.
+	 */
+	SCM call_result = scm_c_with_continuation_barrier(
+		call_idle_handler_inner, data
+	);
+
+	if ( call_result == NULL )
+		return (void *)"ERROR: An exception occured while calling the user-command handler.\n";
+
+	return NULL;
+}

src/call-idle-handler.h

@@ -0,0 +1,20 @@
+#ifndef RIVERGUILE_CALL_IDLE_HANDLER_H
+#define RIVERGUILE_CALL_IDLE_HANDLER_H
+
+#include "seat.h"
+
+enum Idle_handler_event
+{
+	IDLE,
+	RESUME,
+};
+
+struct Call_idle_handler_parameters
+{
+	struct Idle *idle;
+	enum Idle_handler_event event;
+};
+
+void *call_idle_handler (void *data);
+
+#endif

src/call-layout-demand-handler.c

@@ -1,17 +1,16 @@
 #include <assert.h>
 #include <libguile.h>
 
+#include "riverguile.h"
+#include "output.h"
 #include "river-layout-v3.h"
-
 #include "call-layout-demand-handler.h"
 
-extern SCM layout_demand_handler;
-
 static void *call_layout_demand_handler_inner (void *data)
 {
 	struct Call_layout_demand_handler_parameters *params = (struct Call_layout_demand_handler_parameters *)data;
 	return scm_call_5(
-		layout_demand_handler,
+		context.layout_demand_handler,
 		scm_from_uint32(params->view_count),
 		scm_from_uint32(params->width),
 		scm_from_uint32(params->height),
@@ -24,8 +23,8 @@ void *call_layout_demand_handler (void *data)
 {
 	struct Call_layout_demand_handler_parameters *params = (struct Call_layout_demand_handler_parameters *)data;
 
-	assert(layout_demand_handler != NULL);
+	assert(context.layout_demand_handler != NULL);
-	assert(scm_is_true(scm_procedure_p(layout_demand_handler)) == 1);
+	assert(scm_is_true(scm_procedure_p(context.layout_demand_handler)) == 1);
 
 	/* Continuation barrier causes stack unwind on exceptions (i.e. errors
 	 * in the user defined layout demand handler) to stop here. Otherwise

src/call-layout-demand-handler.h

@@ -3,8 +3,6 @@
 
 #include <libguile.h>
 
-#include "types.h"
-
 struct Call_layout_demand_handler_parameters
 {
 	uint32_t view_count, width, height, serial, tags;

src/call-user-command-handler.c

@@ -1,16 +1,15 @@
 #include <assert.h>
 #include <libguile.h>
 
-#include "types.h"
+#include "riverguile.h"
+#include "output.h"
 #include "call-user-command-handler.h"
 
-extern SCM user_command_handler;
-
 static void *call_user_command_handler_inner (void *data)
 {
 	struct Call_user_command_parameters *params = (struct Call_user_command_parameters *)data;
 	return scm_call_3(
-		user_command_handler,
+		context.user_command_handler,
 		scm_from_utf8_string(params->cmd),
 		scm_from_uint32(params->output->user_command_tags),
 		scm_from_uint32(params->output->name)
@@ -19,8 +18,8 @@ static void *call_user_command_handler_inner (void *data)
 
 void *call_user_command_handler (void *data)
 {
-	assert(user_command_handler != NULL);
+	assert(context.user_command_handler != NULL);
-	assert(scm_is_true(scm_procedure_p(user_command_handler)) == 1);
+	assert(scm_is_true(scm_procedure_p(context.user_command_handler)) == 1);
 
 	/* Continuation barrier causes stack unwind on exceptions (i.e. errors
 	 * in the user defined user-command handler) to stop here. Otherwise

src/call-user-command-handler.h

@@ -1,7 +1,7 @@
 #ifndef RIVERGUILE_CALL_USER_COMMAND_HANDLER_H
 #define RIVERGUILE_CALL_USER_COMMAND_HANDLER_H
 
-#include "types.h"
+#include "output.h"
 
 struct Call_user_command_parameters
 {

src/load-script.c

@@ -1,6 +1,11 @@
 #include <assert.h>
 #include <stdio.h>
+#include <stdint.h>
 #include <libguile.h>
+#include <string.h>
+
+#include "riverguile.h"
+#include "seat.h"
 
 /**
  * ISO C forbids casting a function pointer to a void pointer because on some
@@ -12,8 +17,35 @@
 #define scm_c_define_gsubr_fix(NAME, REQ, OPT, RST, FN) \
 	{ const long int ptr = (long int)FN; scm_c_define_gsubr(NAME, REQ, OPT, RST, (void *)ptr); }
 
-extern SCM layout_demand_handler;
+static uint32_t extract_ms_from_idle_key (SCM key)
-extern SCM user_command_handler;
+{
+	SCM key_split = scm_string_split(
+		scm_symbol_to_string(key),
+		scm_to_char_set(scm_from_utf8_string(":"))
+	);
+	if ( scm_to_uint32(scm_length(key_split)) != 2 )
+		goto error;
+
+	SCM maybe_number = scm_string_to_number(scm_cadr(key_split), scm_from_int(10));
+	if ( scm_is_false(maybe_number) == 1 )
+		goto error;
+
+	int32_t ms = scm_to_int32(maybe_number);
+	if ( ms < 0 )
+		goto error;
+
+	return (uint32_t)ms * 1000;
+
+error:
+	scm_error_scm(
+		scm_from_utf8_symbol("wrong-type-arg"),
+		scm_from_utf8_string("install-handler"),
+		scm_from_utf8_string("First argument: Excpected 'idle:<positive integer>."),
+		SCM_BOOL_F,
+		scm_list_1(key)
+	);
+	return 0;
+}
 
 static SCM install_handler (SCM key, SCM proc)
 {
@@ -42,10 +74,33 @@ static SCM install_handler (SCM key, SCM proc)
 		return SCM_UNSPECIFIED;
 	}
 
-	if (scm_is_eq(scm_from_utf8_symbol("layout-demand"), key))
+	if ( scm_is_eq(scm_from_utf8_symbol("layout-demand"), key) == 1 )
-		layout_demand_handler = proc;
+		context.layout_demand_handler = proc;
-	else if (scm_is_eq(scm_from_utf8_symbol("user-command"), key))
+	else if ( scm_is_eq(scm_from_utf8_symbol("user-command"), key) == 1)
-		user_command_handler = proc;
+		context.user_command_handler = proc;
+	else if ( scm_is_true(scm_string_prefix_p(scm_from_utf8_string("idle:"), scm_symbol_to_string(key),
+		scm_from_int(0), scm_from_int(5),
+		scm_from_int(0), scm_string_length(scm_symbol_to_string(key)))) == 1 )
+	{
+		uint32_t ms = extract_ms_from_idle_key(key);
+
+		struct Idle *idle = calloc(1, sizeof(struct Idle));
+		if ( idle == NULL )
+		{
+			scm_error_scm(
+				scm_from_utf8_symbol("memory-allocation-error"),
+				scm_from_utf8_string("install-handler"),
+				SCM_BOOL_F,
+				SCM_BOOL_F,
+				SCM_BOOL_F
+			);
+			return SCM_UNSPECIFIED;
+		}
+
+		idle->ms = ms;
+		idle->handler = proc;
+		wl_list_insert(&context.unconfigured_idles, &idle->link);
+	}
 	else
 	{
 		scm_error_scm(
@@ -91,13 +146,13 @@ void *load_script (void *data)
 	if ( call_result == NULL )
 		return (void *)"ERROR: Fatal error while loading layout script.\n";
 
-	if ( layout_demand_handler == NULL )
+	if ( context.layout_demand_handler == NULL )
 		return (void *)"ERROR: No layout demand handler installed.\n";
 
 	/* Checked in the installer functions. */
-	assert(scm_is_true(scm_procedure_p(layout_demand_handler)) == 1);
+	assert(scm_is_true(scm_procedure_p(context.layout_demand_handler)) == 1);
-	if ( user_command_handler != NULL )
+	if ( context.user_command_handler != NULL )
-		assert(scm_is_true(scm_procedure_p(user_command_handler)) == 1);
+		assert(scm_is_true(scm_procedure_p(context.user_command_handler)) == 1);
 
 	return NULL;
 }

src/output.c

@@ -0,0 +1,121 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <libguile.h>
+#include <assert.h>
+
+#include "river-layout-v3.h"
+
+#include "riverguile.h"
+#include "output.h"
+#include "call-layout-demand-handler.h"
+#include "call-user-command-handler.h"
+
+static void layout_handle_layout_demand (void *data, struct river_layout_v3 *river_layout_v3,
+		uint32_t view_count, uint32_t width, uint32_t height, uint32_t tags, uint32_t serial)
+{
+	struct Output *output = (struct Output *)data;
+
+	struct Call_layout_demand_handler_parameters params = {
+		.view_count = view_count,
+		.width = width,
+		.height = height,
+		.serial = serial,
+		.tags = tags,
+		.output = output,
+	};
+
+	void *res = scm_with_guile(call_layout_demand_handler, (void *)&params);
+	if ( res != NULL )
+	{
+		fputs(res, stderr);
+		fputs("INFO: This error is not fatal.\n", stderr);
+		return;
+	}
+
+	// TODO allow setting layout name from user installed layout demand handler
+	river_layout_v3_commit(output->layout, "(🐦)", serial);
+}
+
+static void layout_handle_user_command (void *data,
+		struct river_layout_v3 *river_layout, const char *command)
+{
+	if ( context.user_command_handler == NULL )
+		return;
+
+	struct Output *output = (struct Output *)data;
+
+	struct Call_user_command_parameters params = {
+		.cmd = command,
+		.output = output,
+	};
+
+	void *res = scm_with_guile(call_user_command_handler, (void *)&params);
+	if ( res != NULL )
+	{
+		fputs(res, stderr);
+		fputs("INFO: This error is not fatal.\n", stderr);
+	}
+}
+
+static void layout_handle_user_command_tags (void *data,
+		struct river_layout_v3 *river_layout, uint32_t tags)
+{
+	struct Output *output = (struct Output *)data;
+	output->user_command_tags = tags;
+}
+
+static void layout_handle_namespace_in_use (void *data, struct river_layout_v3 *river_layout_v3)
+{
+	fputs("ERROR: Namespace already in use.\n", stderr);
+	context.ret = EXIT_FAILURE;
+	context.loop = false;
+}
+
+static const struct river_layout_v3_listener layout_listener = {
+	.namespace_in_use  = layout_handle_namespace_in_use,
+	.layout_demand     = layout_handle_layout_demand,
+	.user_command      = layout_handle_user_command,
+	.user_command_tags = layout_handle_user_command_tags,
+};
+
+void output_configure (struct Output *output)
+{
+	if ( context.layout_manager == NULL )
+		return;
+	if (output->configured)
+		return;
+
+	output->layout = river_layout_manager_v3_get_layout(
+		context.layout_manager, output->wl_output, "riverguile"
+	);
+	river_layout_v3_add_listener(output->layout, &layout_listener, output);
+	output->configured = true;
+}
+
+struct Output *output_create (struct wl_output *wl_output, uint32_t name)
+{
+	struct Output *output = calloc(1, sizeof(struct Output));
+	if ( output == NULL )
+	{
+		fprintf(stderr, "ERROR: calloc: %s\n", strerror(errno));
+		return NULL;
+	}
+
+	output->name = name;
+	output->wl_output = wl_output;
+	output_configure(output);
+
+	return output;
+}
+
+void output_destroy (struct Output *output)
+{
+	if ( output->layout != NULL )
+		river_layout_v3_destroy(output->layout);
+	assert(output->wl_output != NULL);
+	wl_output_destroy(output->wl_output);
+	free(output);
+}
+

src/output.h

@@ -1,5 +1,5 @@
-#ifndef RIVERGUILE_TYPES_H_INCLUDED
+#ifndef RIVERGUILE_OUTPUT_H
-#define RIVERGUILE_TYPES_H_INCLUDED
+#define RIVERGUILE_OUTPUT_H
 
 #include <stdbool.h>
 #include <wayland-client.h>
@@ -22,4 +22,8 @@ struct Output
 	uint32_t user_command_tags;
 };
 
+struct Output *output_create (struct wl_output *wl_output, uint32_t name);
+void output_destroy (struct Output *output);
+void output_configure (struct Output *output);
+
 #endif

src/riverguile.c

@@ -19,168 +19,80 @@
 #endif
 
 #include "river-layout-v3.h"
+#include "ext-idle-notify-v1.h"
 
-#include "types.h"
-#include "call-layout-demand-handler.h"
-#include "call-user-command-handler.h"
 #include "load-script.h"
+#include "riverguile.h"
+#include "output.h"
+#include "seat.h"
 
-bool loop = true;
+struct Context context = {
-int ret = EXIT_SUCCESS;
+	/* Handlers are initially NULL instead of SCM_EOL because I am not sure whether
-
-jmp_buf skip_main_loop;
-
-struct wl_display *wl_display = NULL;
-struct wl_registry *wl_registry = NULL;
-struct wl_callback *sync_callback = NULL;
-struct river_layout_manager_v3 *layout_manager = NULL;
-
-struct wl_list outputs;
-
-/* Handlers are initially NULL instead of SCM_EOL because I am not sure whether
 	 * scm_null_p() is safe to use outside of a guile context and if yes, whether
 	 * that is intended or will disappear in the future. Special care must be taken
 	 * to never call any scm_* function on these while they are NULL.
 	 */
-SCM layout_demand_handler = NULL;
+	.layout_demand_handler = NULL,
-SCM user_command_handler = NULL;
+	.user_command_handler = NULL,
 
-static void layout_handle_layout_demand (void *data, struct river_layout_v3 *river_layout_v3,
+	.loop = true,
-		uint32_t view_count, uint32_t width, uint32_t height, uint32_t tags, uint32_t serial)
+	.ret = EXIT_SUCCESS,
-{
-	struct Output *output = (struct Output *)data;
-
-	struct Call_layout_demand_handler_parameters params = {
-		.view_count = view_count,
-		.width = width,
-		.height = height,
-		.serial = serial,
-		.tags = tags,
-		.output = output,
-	};
-
-	void *res = scm_with_guile(call_layout_demand_handler, (void *)&params);
-	if ( res != NULL )
-	{
-		fputs(res, stderr);
-		fputs("INFO: This error is not fatal.\n", stderr);
-		return;
-	}
-
-	// TODO allow setting layout name from user installed layout demand handler
-	river_layout_v3_commit(output->layout, "(🐦)", serial);
-}
-
-static void layout_handle_user_command (void *data,
-		struct river_layout_v3 *river_layout, const char *command)
-{
-	if ( user_command_handler == NULL )
-		return;
-
-	struct Output *output = (struct Output *)data;
-
-	struct Call_user_command_parameters params = {
-		.cmd = command,
-		.output = output,
-	};
-
-	void *res = scm_with_guile(call_user_command_handler, (void *)&params);
-	if ( res != NULL )
-	{
-		fputs(res, stderr);
-		fputs("INFO: This error is not fatal.\n", stderr);
-	}
-}
-
-static void layout_handle_user_command_tags (void *data,
-		struct river_layout_v3 *river_layout, uint32_t tags)
-{
-	struct Output *output = (struct Output *)data;
-	output->user_command_tags = tags;
-}
-
-static void layout_handle_namespace_in_use (void *data, struct river_layout_v3 *river_layout_v3)
-{
-	fputs("ERROR: Namespace already in use.\n", stderr);
-	ret = EXIT_FAILURE;
-	loop = false;
-}
-
-static const struct river_layout_v3_listener layout_listener = {
-	.namespace_in_use  = layout_handle_namespace_in_use,
-	.layout_demand     = layout_handle_layout_demand,
-	.user_command      = layout_handle_user_command,
-	.user_command_tags = layout_handle_user_command_tags,
 };
 
-static void output_configure (struct Output *output)
+jmp_buf skip_main_loop;
-{
-	if ( layout_manager == NULL )
-		return;
-	if (output->configured)
-		return;
-
-	output->layout = river_layout_manager_v3_get_layout(
-		layout_manager, output->wl_output, "riverguile"
-	);
-	river_layout_v3_add_listener(output->layout, &layout_listener, output);
-	output->configured = true;
-}
-
-static struct Output *output_create (struct wl_output *wl_output)
-{
-	struct Output *output = calloc(1, sizeof(struct Output));
-	if ( output == NULL )
-	{
-		fprintf(stderr, "ERROR: calloc: %s\n", strerror(errno));
-		return NULL;
-	}
-
-	output->wl_output = wl_output;
-	output_configure(output);
-	return output;
-}
-
-static void output_destroy (struct Output *output)
-{
-	if ( output->layout != NULL )
-		river_layout_v3_destroy(output->layout);
-	assert(output->wl_output != NULL);
-	wl_output_destroy(output->wl_output);
-	free(output);
-}
 
 static void registry_handle_global (void *data, struct wl_registry *registry,
 		uint32_t name, const char *interface, uint32_t version)
 {
 	if ( strcmp(interface, river_layout_manager_v3_interface.name) == 0 )
 	{
-		layout_manager = wl_registry_bind(
+		context.layout_manager = wl_registry_bind(
 			registry, name, &river_layout_manager_v3_interface, 2
 		);
 	}
+	else if ( strcmp(interface, ext_idle_notifier_v1_interface.name) == 0 )
+	{
+		context.idle_notifier = wl_registry_bind(
+			registry, name, &ext_idle_notifier_v1_interface, 1
+		);
+	}
 	else if ( strcmp(interface, wl_output_interface.name) == 0 )
 	{
 		struct wl_output *wl_output = wl_registry_bind(
 			registry, name, &wl_output_interface, 1
 		);
-		struct Output *output = output_create(wl_output);
+		struct Output *output = output_create(wl_output, name);
 		if ( output == NULL )
 		{
 			wl_output_destroy(wl_output);
-			ret = EXIT_FAILURE;
+			context.ret = EXIT_FAILURE;
-			loop = false;
+			context.loop = false;
 			return;
 		}
-		wl_list_insert(&outputs, &output->link);
+		wl_list_insert(&context.outputs, &output->link);
+	}
+	else if ( strcmp(interface, wl_seat_interface.name) == 0 )
+	{
+		struct wl_seat *wl_seat = wl_registry_bind(
+			registry, name, &wl_seat_interface, 1
+		);
+		struct Seat *seat = seat_create(wl_seat, name);
+		if ( seat == NULL )
+		{
+			wl_seat_destroy(wl_seat);
+			context.ret = EXIT_FAILURE;
+			context.loop = false;
+			return;
+		}
+		wl_list_insert(&context.seats, &seat->link);
 	}
 }
 
 static void registry_handle_global_remove (void *data, struct wl_registry *registry,
 		uint32_t name)
 {
-	struct Output *output, *tmp;
+	struct Output *output, *tmp_o;
-	wl_list_for_each_safe(output, tmp, &outputs, link)
+	wl_list_for_each_safe(output, tmp_o, &context.outputs, link)
 	{
 		if ( output->name != name )
 			continue;
@@ -188,6 +100,16 @@ static void registry_handle_global_remove (void *data, struct wl_registry *regis
 		output_destroy(output);
 		return;
 	}
+
+	struct Seat *seat, *tmp_s;
+	wl_list_for_each_safe(seat, tmp_s, &context.seats, link)
+	{
+		if ( seat->name != name )
+			continue;
+		wl_list_remove(&seat->link);
+		seat_destroy(seat);
+		return;
+	}
 }
 
 static const struct wl_registry_listener registry_listener = {
@@ -198,22 +120,41 @@ static const struct wl_registry_listener registry_listener = {
 static void sync_handle_done (void *data, struct wl_callback *wl_callback, uint32_t other_data)
 {
 	wl_callback_destroy(wl_callback);
-	sync_callback = NULL;
+	context.sync_callback = NULL;
 
-	if ( layout_manager == NULL )
+	if ( context.layout_manager == NULL )
 	{
 		fputs("ERROR: Wayland server  does not support river-layout-v3.\n", stderr);
-		ret = EXIT_FAILURE;
+		context.ret = EXIT_FAILURE;
-		loop = false;
+		context.loop = false;
 		return;
 	}
 
+	if ( context.idle_notifier == NULL )
+	{
+		if ( wl_list_length(&context.unconfigured_idles) > 0 )
+		{
+			fputs("ERROR: Wayland server  does not support ext-idle-notify-v1.\n", stderr);
+			fputs("INFO: This error is not fatal.\n", stderr);
+		}
+	}
+	else
+	{
+		struct Seat *seat;
+		wl_list_for_each(seat, &context.seats, link)
+			break;
+
+		struct Idle *idle, *tmp_i;
+		wl_list_for_each_safe(idle, tmp_i, &context.unconfigured_idles, link)
+			idle_configure(idle, seat);
+	}
+
 	/* If outputs were registered before the river_layout_manager is
 	 * available, they won't have a river_layout, so we need to create
 	 * those here.
 	 */
 	struct Output *output;
-	wl_list_for_each(output, &outputs, link)
+	wl_list_for_each(output, &context.outputs, link)
 		output_configure(output);
 }
 
@@ -224,7 +165,7 @@ static const struct wl_callback_listener sync_callback_listener = {
 static void handle_interrupt (int signum)
 {
 	fputs("Killed 💀\n", stderr);
-	loop = false;
+	context.loop = false;
 	longjmp(skip_main_loop, 1);
 }
 
@@ -353,13 +294,16 @@ int main(int argc, char *argv[])
 	signal(SIGSEGV, handle_error);
 	signal(SIGFPE, handle_error);
 	signal(SIGINT, handle_interrupt);
-	wl_list_init(&outputs);
+
+	wl_list_init(&context.outputs);
+	wl_list_init(&context.seats);
+	wl_list_init(&context.unconfigured_idles);
 
 	// TODO use argv[1] if present
 	char *path = get_script_path();
 	if ( path == NULL )
 	{
-		ret = EXIT_FAILURE;
+		context.ret = EXIT_FAILURE;
 		goto early_exit;
 	}
 
@@ -367,8 +311,8 @@ int main(int argc, char *argv[])
 	if ( res != NULL )
 	{
 		fputs((char *)res, stderr);
-		ret = EXIT_FAILURE;
+		context.ret = EXIT_FAILURE;
-		loop = false;
+		context.loop = false;
 		goto early_exit;
 	}
 
@@ -381,44 +325,62 @@ int main(int argc, char *argv[])
 	if ( display_name == NULL )
 	{
 		fputs("ERROR: WAYLAND_DISPLAY is not set.\n", stderr);
-		ret = EXIT_FAILURE;
+		context.ret = EXIT_FAILURE;
 		goto early_exit;
 	}
 
-	wl_display = wl_display_connect(display_name);
+	context.wl_display = wl_display_connect(display_name);
-	if ( wl_display == NULL )
+	if ( context.wl_display == NULL )
 	{
 		fputs("ERROR: Can not connect to wayland display.\n", stderr);
-		ret = EXIT_FAILURE;
+		context.ret = EXIT_FAILURE;
 		goto early_exit;
 	}
 
-	wl_registry = wl_display_get_registry(wl_display);
+	context.wl_registry = wl_display_get_registry(context.wl_display);
-	wl_registry_add_listener(wl_registry, &registry_listener, NULL);
+	wl_registry_add_listener(context.wl_registry, &registry_listener, NULL);
 
-	sync_callback = wl_display_sync(wl_display);
+	context.sync_callback = wl_display_sync(context.wl_display);
-	wl_callback_add_listener(sync_callback, &sync_callback_listener, NULL);
+	wl_callback_add_listener(context.sync_callback, &sync_callback_listener, NULL);
 
 	if ( setjmp(skip_main_loop) == 0 )
-		while ( loop && wl_display_dispatch(wl_display) > 0 );
+		while ( context.loop && wl_display_dispatch(context.wl_display) > 0 );
 
-	struct Output *output, *tmp;
+	struct Idle *idle, *tmp_i;
-	wl_list_for_each_safe(output, tmp, &outputs, link)
+	wl_list_for_each_safe(idle, tmp_i, &context.unconfigured_idles, link)
+	{
+		wl_list_remove(&idle->link);
+		idle_destroy(idle);
+	}
+
+	struct Output *output, *tmp_o;
+	wl_list_for_each_safe(output, tmp_o, &context.outputs, link)
 	{
 		wl_list_remove(&output->link);
 		output_destroy(output);
 	}
 
-	if ( sync_callback != NULL )
+	struct Seat *seat, *tmp_s;
-		wl_callback_destroy(sync_callback);
+	wl_list_for_each_safe(seat, tmp_s, &context.seats, link)
-	if ( wl_registry != NULL )
+	{
-		wl_registry_destroy(wl_registry);
+		wl_list_remove(&seat->link);
-	wl_display_disconnect(wl_display);
+		seat_destroy(seat);
+	}
+
+	if ( context.idle_notifier != NULL )
+		ext_idle_notifier_v1_destroy(context.idle_notifier);
+	if ( context.layout_manager != NULL )
+		river_layout_manager_v3_destroy(context.layout_manager);
+	if ( context.sync_callback != NULL )
+		wl_callback_destroy(context.sync_callback);
+	if ( context.wl_registry != NULL )
+		wl_registry_destroy(context.wl_registry);
+	wl_display_disconnect(context.wl_display);
 
 early_exit:
 	if ( path != NULL )
 		free(path);
 
-	return ret;
+	return context.ret;
 }
 

src/riverguile.h

@@ -0,0 +1,33 @@
+#ifndef RIVERGUILE_RIVERGUILE_H
+#define RIVERGUILE_RIVERGUILE_H
+
+#include <stdbool.h>
+#include <wayland-client.h>
+#include <libguile.h>
+
+#include "seat.h"
+
+struct Context
+{
+	SCM layout_demand_handler;
+	SCM user_command_handler;
+
+	bool loop;
+	int ret;
+
+	struct wl_display              *wl_display;
+	struct wl_registry             *wl_registry;
+	struct wl_callback             *sync_callback;
+	struct river_layout_manager_v3 *layout_manager;
+	struct ext_idle_notifier_v1    *idle_notifier;
+
+	struct wl_list seats;
+	struct wl_list outputs;
+
+	/* Idles are created before we connect to the server and bind seats. */
+	struct wl_list unconfigured_idles;
+};
+
+extern struct Context context;
+
+#endif

src/seat.c

@@ -0,0 +1,112 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "ext-idle-notify-v1.h"
+
+#include "riverguile.h"
+#include "seat.h"
+#include "call-idle-handler.h"
+
+static void idle_notification_handle_idled (void *data,
+		      struct ext_idle_notification_v1 *ext_idle_notification_v1)
+{
+	struct Idle *idle = (struct Idle *)data;
+	assert(idle->handler != NULL);
+
+	struct Call_idle_handler_parameters params = {
+		.idle = idle,
+		.event = IDLE,
+	};
+	call_idle_handler(&params);
+}
+
+static void idle_notification_handle_resumed (void *data,
+		      struct ext_idle_notification_v1 *ext_idle_notification_v1)
+{
+	struct Idle *idle = (struct Idle *)data;
+	assert(idle->handler != NULL);
+
+	struct Call_idle_handler_parameters params = {
+		.idle = idle,
+		.event = RESUME,
+	};
+	call_idle_handler(&params);
+}
+
+static const struct ext_idle_notification_v1_listener idle_notification_listener = {
+	.idled = idle_notification_handle_idled,
+	.resumed = idle_notification_handle_resumed,
+};
+
+void idle_configure (struct Idle *idle, struct Seat *seat)
+{
+	assert(idle->seat == NULL);
+
+	idle->idle_notification = ext_idle_notifier_v1_get_idle_notification(
+		context.idle_notifier,
+		idle->ms,
+		seat->wl_seat
+	);
+
+	ext_idle_notification_v1_add_listener(
+		idle->idle_notification,
+		&idle_notification_listener,
+		idle
+	);
+
+	wl_list_remove(&idle->link);
+	wl_list_insert(&seat->idles, &idle->link);
+	idle->seat = seat;
+}
+
+void idle_destroy (struct Idle *idle)
+{
+	// TODO XXX how do we tell guile it is allowed to clean up the handler?
+	//          maybe by entering guile mode one more time at exit?
+	//          we could also define an 'exit handler
+	if ( idle->idle_notification != NULL )
+	{
+		assert(idle->seat != NULL);
+		ext_idle_notification_v1_destroy(idle->idle_notification);
+	}
+	else
+	{
+		assert(idle->seat == NULL);
+	}
+	free(idle);
+}
+
+struct Seat *seat_create (struct wl_seat *wl_seat, uint32_t name)
+{
+	struct Seat *seat = calloc(1, sizeof(struct Seat));
+	if ( seat == NULL )
+	{
+		fprintf(stderr, "ERROR: calloc: %s\n", strerror(errno));
+		return NULL;
+	}
+
+	seat->name = name;
+	seat->wl_seat = wl_seat;
+
+	wl_list_init(&seat->idles);
+
+	return seat;
+}
+
+void seat_destroy (struct Seat *seat)
+{
+	struct Idle *idle, *tmp_i;
+	wl_list_for_each_safe(idle, tmp_i, &seat->idles, link)
+	{
+		wl_list_remove(&idle->link);
+		idle_destroy(idle);
+	}
+
+	assert(seat->wl_seat != NULL);
+	wl_seat_destroy(seat->wl_seat);
+	free(seat);
+}
+

src/seat.h

@@ -0,0 +1,31 @@
+#ifndef RIVERGUILE_SEAT_H
+#define RIVERGUILE_SEAT_H
+
+#include <wayland-client.h>
+#include <libguile.h>
+
+struct Seat
+{
+	struct wl_list link;
+	struct wl_seat *wl_seat;
+	uint32_t name;
+
+	struct wl_list idles;
+};
+
+struct Idle
+{
+	struct Seat *seat;
+	struct wl_list link;
+	struct ext_idle_notification_v1 *idle_notification;
+	SCM handler;
+	uint32_t ms;
+};
+
+struct Seat *seat_create (struct wl_seat *wl_seat, uint32_t name);
+void seat_destroy (struct Seat *seat);
+
+void idle_configure (struct Idle *idle, struct Seat *seat);
+void idle_destroy (struct Idle *idle);
+
+#endif