add river-control-unstable-v1 support

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