Add pointer_constraint command

include/sway/commands.h

@@ -153,6 +153,7 @@ sway_cmd cmd_new_window;
 sway_cmd cmd_no_focus;
 sway_cmd cmd_output;
 sway_cmd cmd_permit;
+sway_cmd cmd_pointer_constraint;
 sway_cmd cmd_popup_during_fullscreen;
 sway_cmd cmd_reject;
 sway_cmd cmd_reload;

include/sway/config.h

@@ -143,6 +143,7 @@ struct seat_config {
 	int fallback; // -1 means not set
 	list_t *attachments; // list of seat_attachment configs
 	int hide_cursor_timeout;
+	bool allow_constrain;
 };
 
 enum config_dpms {

sway/commands.c

@@ -81,6 +81,7 @@ static struct cmd_handler handlers[] = {
 	{ "no_focus", cmd_no_focus },
 	{ "output", cmd_output },
 	{ "popup_during_fullscreen", cmd_popup_during_fullscreen },
+	{ "pointer_constraint", cmd_pointer_constraint },
 	{ "seat", cmd_seat },
 	{ "set", cmd_set },
 	{ "show_marks", cmd_show_marks },

sway/commands/pointer_constraint.c

@@ -0,0 +1,51 @@
+#include <string.h>
+#include <wlr/types/wlr_pointer_constraints_v1.h>
+#include "sway/commands.h"
+#include "sway/config.h"
+#include "sway/input/cursor.h"
+#include "sway/input/seat.h"
+
+enum operation {
+	OP_ENABLE,
+	OP_DISABLE,
+	OP_ESCAPE,
+};
+
+// pointer_constraint [enable|disable|escape]
+struct cmd_results *cmd_pointer_constraint(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "pointer_constraint", EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+
+	enum operation op;
+	if (strcmp(argv[0], "enable") == 0) {
+		op = OP_ENABLE;
+	} else if (strcmp(argv[0], "disable") == 0) {
+		op = OP_DISABLE;
+	} else if (strcmp(argv[0], "escape") == 0) {
+		op = OP_ESCAPE;
+	} else {
+		return cmd_results_new(CMD_FAILURE, "Expected enable|disable|escape");
+	}
+
+	if (op == OP_ESCAPE && config->reading) {
+		return cmd_results_new(CMD_FAILURE, "Can only escape at runtime.");
+	}
+
+	struct sway_cursor *cursor = config->handler_context.seat->cursor;
+	struct seat_config *seat_config = seat_get_config(cursor->seat);
+	switch (op) {
+	case OP_ENABLE:
+		seat_config->allow_constrain = true;
+		break;
+	case OP_DISABLE:
+		seat_config->allow_constrain = false;
+		/* fallthrough */
+	case OP_ESCAPE:
+		sway_cursor_constrain(cursor, NULL);
+		break;
+	}
+
+	return cmd_results_new(CMD_SUCCESS, NULL);
+}

sway/config/seat.c

@@ -26,6 +26,7 @@ struct seat_config *new_seat_config(const char* name) {
 		return NULL;
 	}
 	seat->hide_cursor_timeout = -1;
+	seat->allow_constrain = true;
 
 	return seat;
 }

sway/input/cursor.c

@@ -1454,6 +1454,11 @@ void handle_pointer_constraint(struct wl_listener *listener, void *data) {
 
 void sway_cursor_constrain(struct sway_cursor *cursor,
 		struct wlr_pointer_constraint_v1 *constraint) {
+	struct seat_config *config = seat_get_config(cursor->seat);
+	if (!config->allow_constrain) {
+		return;
+	}
+
 	if (cursor->active_constraint == constraint) {
 		return;
 	}

sway/meson.build

@@ -75,6 +75,7 @@ sway_sources = files(
 	'commands/nop.c',
 	'commands/output.c',
 	'commands/popup_during_fullscreen.c',
+	'commands/pointer_constraint.c',
 	'commands/reload.c',
 	'commands/rename.c',
 	'commands/resize.c',

sway/sway.5.scd

@@ -539,6 +539,11 @@ The default colors are:
 	\* may be used in lieu of a specific output name to configure all outputs.
 	A list of output names may be obtained via *swaymsg -t get_outputs*.
 
+*pointer_constraint* enable|disable|escape
+	Enables or disables the ability for clients to capture the cursor (enabled
+	by default). This is primarily useful for video games. The "escape" command
+	can be used at runtime to escape from a captured client.
+
 *popup_during_fullscreen* smart|ignore|leave_fullscreen
 	Determines what to do when a fullscreen view opens a dialog.
 	If _smart_ (the default), the dialog will be displayed. If _ignore_, the