add river-control-unstable-v1 support

Makefile

@@ -21,9 +21,11 @@ OBJ=src/riverguile.o $\
 	src/call-exit-handler.o $\
 	src/load-script.o $\
 	protocol/river-layout-v3.o $\
-	protocol/ext-idle-notify-v1.o
+	protocol/ext-idle-notify-v1.o $\
+	protocol/river-control-unstable-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
+	protocol/ext-idle-notify-v1.c protocol/ext-idle-notify-v1.h $\
+	protocol/river-control-unstable-v1.c protocol/river-control-unstable-v1.h
 
 all: riverguile
 

doc/riverguile.1

@@ -23,22 +23,60 @@ If certain handlers are installed it will run continously.
 .P
 Uppon launch, riverguile tries to load the script from the following paths
 in the given order:
-.IP  \(bu 2
+.IP \(bu 2
 \fBlayout.scm\fR
-.IP  \(bu 2
+.IP \(bu 2
 \fB$XDG_CONFIG_HOME/river/layout.scm\fR
-.IP  \(bu 2
+.IP \(bu 2
 \fB$HOME/.config/river/layout.scm\fR
-.IP  \(bu 2
+.IP \(bu 2
 \fB/etc/riverguile/layout.scm\fR
+.
+.
+.SH COMMANDS
 .P
+Riverguile exposes the special procedure
+\fB(riverctl \fR\fIfirst\fR . \fIrest\fR\fB)\fR, which can be used to send
+commands to the server in a similar fashion to
+.BR riverctl (1).
+All arguments must be strings.
+.P
+Here is an example of using this procedure to instruct river to spawn an
+instance of the
+.BR foot (1)
+terminal emulator:
+.P
+.RS
+.EX
+(\fBriverctl\fR "spawn" "foot")
+.EE
+.RE
+.P
+To make using this procedure more ergonomic you likely want to wrap it in a
+macro like this:
+.P
+.RS
+.EX
+(\fBdefine-syntax\fR R
+  (\fBsyntax-rules\fR ()
+    ((R first) (riverctl (\fBsymbol->string\fR 'first)))
+    ((R first . rest) (\fBapply\fR riverctl
+                             (\fBmap\fR \fBsymbol->string\fR
+                                  (\fBappend\fR '(first) 'rest))))))
+
+(R spawn foot)
+(R spawn \fB#{\fRnotify-send notification!\fB}#\fR)
+.EE
+.RE
+.P
+This macro can of course be further modified to suit your specific needs.
 .
 .
 .SH EVENT HANDLERS
 .P
-In the context of the script, a special procedure
+Riverguile exposes the special procedure
-\fB(install-handler \fR\fIkey\fR \fIproc\fR\fB)\fR is available, which can be
+\fB(install-handler \fR\fIkey\fR \fIproc\fR\fB)\fR, which can be used to install
-used to install event handlers.
+event handlers.
 The parameter \fIkey\fR is a symbol indicating for which event to install
 the procedure \fIproc\fR.
 The following keys are currently evailable:

protocol/river-control-unstable-v1.xml

@@ -0,0 +1,85 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="river_control_unstable_v1">
+  <copyright>
+    Copyright 2020 The River Developers
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+  </copyright>
+
+  <interface name="zriver_control_v1" version="1">
+    <description summary="run compositor commands">
+      This interface allows clients to run compositor commands and receive a
+      success/failure response with output or a failure message respectively.
+
+      Each command is built up in a series of add_argument requests and
+      executed with a run_command request. The first argument is the command
+      to be run.
+
+      A complete list of commands should be made available in the man page of
+      the compositor.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the river_control object">
+        This request indicates that the client will not use the
+        river_control object any more. Objects that have been created
+        through this instance are not affected.
+      </description>
+    </request>
+
+    <request name="add_argument">
+      <description summary="add an argument to the current command">
+        Arguments are stored by the server in the order they were sent until
+        the run_command request is made.
+      </description>
+      <arg name="argument" type="string" summary="the argument to add"/>
+    </request>
+
+    <request name="run_command">
+      <description summary="run the current command">
+        Execute the command built up using the add_argument request for the
+        given seat.
+      </description>
+      <arg name="seat" type="object" interface="wl_seat"/>
+      <arg name="callback" type="new_id" interface="zriver_command_callback_v1"
+        summary="callback object"/>
+    </request>
+  </interface>
+
+  <interface name="zriver_command_callback_v1" version="1">
+    <description summary="callback object">
+      This object is created by the run_command request. Exactly one of the
+      success or failure events will be sent. This object will be destroyed
+      by the compositor after one of the events is sent.
+    </description>
+
+    <event name="success" type="destructor">
+      <description summary="command successful">
+        Sent when the command has been successfully received and executed by
+        the compositor. Some commands may produce output, in which case the
+        output argument will be a non-empty string.
+      </description>
+      <arg name="output" type="string" summary="the output of the command"/>
+    </event>
+
+    <event name="failure" type="destructor">
+      <description summary="command failed">
+        Sent when the command could not be carried out. This could be due to
+        sending a non-existent command, no command, not enough arguments, too
+        many arguments, invalid arguments, etc.
+      </description>
+      <arg name="failure_message" type="string"
+        summary="a message explaining why failure occurred"/>
+    </event>
+  </interface>
+</protocol>

src/load-script.c

@@ -8,6 +8,8 @@
 #include "output.h"
 #include "seat.h"
 
+#include "river-control-unstable-v1.h"
+
 /**
  * ISO C forbids casting a function pointer to a void pointer because on some
  * architectures they have different sizes. However scm_c_define_gsubr() wants
@@ -155,6 +157,72 @@ static SCM install_handler (SCM key, SCM proc)
 	return SCM_BOOL_T;
 }
 
+static SCM riverctl (SCM first, SCM rest)
+{
+	if ( context.river_control == NULL )
+	{
+		fputs("ERROR: User script attempts to send river command but river-control-unstable-v1 not available.\n", stderr);
+		fputs("INFO: This error is not fatal, however riverguile will not be able to send any commands to river.\n", stderr);
+		return SCM_BOOL_F;
+	}
+	if ( wl_list_length(&context.seats) == 0 )
+	{
+		fputs("ERROR: User script attempts to send river command but server did not advertise any seats.\n", stderr);
+		fputs("INFO: This error is not fatal, however riverguile will not be able to send any commands to river.\n", stderr);
+		return SCM_BOOL_F;
+	}
+
+	if ( scm_is_string(first) != 1 )
+		goto error;
+
+	assert(scm_is_true(scm_list_p(rest)) == 1);
+	const uint32_t rest_len = scm_to_uint32(scm_length(rest));
+	for (uint32_t i = 0; i < rest_len; i++)
+		if ( scm_is_string(scm_list_ref(rest, scm_from_uint32(i))) != 1 )
+			goto error;
+
+	char *first_owned = scm_to_utf8_stringn(first, 0);
+	zriver_control_v1_add_argument(context.river_control, first_owned);
+	free(first_owned);
+
+	for (uint32_t i = 0; i < rest_len; i++)
+	{
+		char *owned = scm_to_utf8_stringn(scm_list_ref(rest, scm_from_uint32(i)), 0);
+		zriver_control_v1_add_argument(context.river_control, owned);
+		free(owned);
+	}
+
+	/* Just use the first seat. River only supports a single one anyway. */
+	struct Seat *seat;
+	wl_list_for_each(seat, &context.seats, link)
+		break;
+
+	/* While river does tell us about the status of the command, I do not
+	 * want to make use of that in riverguile for multiple reasons.
+	 * For one, the reporting is of course async, meaning we could not raise
+	 * a guile error in response to failed commands, even if we wanted to.
+	 * Riverguile could allow to install a handler for the callback, however
+	 * I do not sett the use. There are two riverctl commands that return
+	 * useful data as a string, however using that for scripting would be
+	 * very hacky and I prefer dedicated well designed interfaces. So we
+	 * just destroy the callback before it even fires.
+	 */
+	zriver_command_callback_v1_destroy(
+		zriver_control_v1_run_command(context.river_control, seat->wl_seat)
+	);
+
+	return SCM_BOOL_T;
+error:
+	scm_error_scm(
+		scm_from_utf8_symbol("wrong-type-arg"),
+		scm_from_utf8_string("riverctl"),
+		scm_from_utf8_string("All arguments must be strings."),
+		SCM_BOOL_F,
+		SCM_BOOL_F
+	);
+	return SCM_UNSPECIFIED;
+}
+
 static void *load_script_inner (void *data)
 {
 	const char *path = (char *)data;
@@ -172,6 +240,7 @@ void *load_script (void *data)
 	/* Note: All guile objects are garbage collected. */
 
 	scm_c_define_gsubr_fix("install-handler", 2, 0, 0, install_handler);
+	scm_c_define_gsubr_fix("riverctl", 1, 0, 1, riverctl);
 
 	/* Continuation barrier causes stack unwind on exceptions to stop here.
 	 * Otherwise the entire stack created by scm_with_guile() would be

src/riverguile.c

@@ -20,6 +20,7 @@
 
 #include "river-layout-v3.h"
 #include "ext-idle-notify-v1.h"
+#include "river-control-unstable-v1.h"
 
 #include "load-script.h"
 #include "call-exit-handler.h"
@@ -35,6 +36,7 @@ struct Context context = {
 	 */
 	.layout_demand_handler = NULL,
 	.user_command_handler = NULL,
+	.exit_handler = NULL,
 
 	.loop = true,
 	.ret = EXIT_SUCCESS,
@@ -51,6 +53,12 @@ static void registry_handle_global (void *data, struct wl_registry *registry,
 			registry, name, &river_layout_manager_v3_interface, 2
 		);
 	}
+	else if ( strcmp(interface, zriver_control_v1_interface.name) == 0 )
+	{
+		context.river_control = wl_registry_bind(
+			registry, name, &zriver_control_v1_interface, 1
+		);
+	}
 	else if ( strcmp(interface, ext_idle_notifier_v1_interface.name) == 0 )
 	{
 		context.idle_notifier = wl_registry_bind(
@@ -380,6 +388,8 @@ int main(int argc, char *argv[])
 		ext_idle_notifier_v1_destroy(context.idle_notifier);
 	if ( context.layout_manager != NULL )
 		river_layout_manager_v3_destroy(context.layout_manager);
+	if ( context.river_control != NULL )
+		zriver_control_v1_destroy(context.river_control);
 	if ( context.sync_callback != NULL )
 		wl_callback_destroy(context.sync_callback);
 	if ( context.wl_registry != NULL )

src/riverguile.h

@@ -35,6 +35,7 @@ struct Context
 	struct wl_callback             *sync_callback;
 	struct river_layout_manager_v3 *layout_manager;
 	struct ext_idle_notifier_v1    *idle_notifier;
+	struct zriver_control_v1       *river_control;
 
 	struct wl_list seats;
 	struct wl_list outputs;