input: Add support for keyboard shortcuts inhibit

Adding support for the keyboard shortcuts inhibit protocol allows remote
desktop and virtualisation software to receive all keyboard input in
order to pass it through to their clients so users can fully interact
the their remote/virtual session. The software usually provides its own
key combination to release its "grab" to all keyboard input. The
inhibitor can be deactivated by the user by removing focus from the
surface using another input device such as the pointer.

Use support for the procotol in wlroots to add support to sway. Extend
the input manager with handlers for inhibitor creation and destruction
and appropriate bookkeeping. Attach the inhibitors to the seats they
apply to to avoid having to search the list of all currently existing
inhibitors on every keystroke and passing the inhibitor manager around.
Add a helper function to retrieve the inhibitor applying to the
currently focused surface of a seat, if one exists.

Extend bindsym with a flag for bindings that should be processed even if
an inhibitor is active. Conversely this disables all normal shortcuts if
an inhibitor is found for the currently focused surface in
keyboard::handle_key_event() since they don't have that flag set. Use
above helper function to determine if an inhibitor exists for the
surface that would eventually receive input.

Signed-off-by: Michael Weiser <michael.weiser@gmx.de>

include/sway/config.h

@@ -40,6 +40,7 @@ enum binding_flags {
 	BINDING_TITLEBAR=16, // mouse only; trigger on container titlebar
 	BINDING_CODE=32,     // keyboard only; convert keysyms into keycodes
 	BINDING_RELOAD=64,   // switch only; (re)trigger binding on reload
+	BINDING_INHIBITED=128,	// keyboard only: ignore shortcut inhibitor
 };
 
 /**

include/sway/input/input-manager.h

@@ -2,6 +2,7 @@
 #define _SWAY_INPUT_INPUT_MANAGER_H
 #include <libinput.h>
 #include <wlr/types/wlr_input_inhibitor.h>
+#include <wlr/types/wlr_keyboard_shortcuts_inhibit_v1.h>
 #include <wlr/types/wlr_virtual_keyboard_v1.h>
 #include <wlr/types/wlr_virtual_pointer_v1.h>
 #include "sway/server.h"
@@ -20,12 +21,14 @@ struct sway_input_manager {
 	struct wl_list seats;
 
 	struct wlr_input_inhibit_manager *inhibit;
+	struct wlr_keyboard_shortcuts_inhibit_manager_v1 *keyboard_shortcuts_inhibit;
 	struct wlr_virtual_keyboard_manager_v1 *virtual_keyboard;
 	struct wlr_virtual_pointer_manager_v1 *virtual_pointer;
 
 	struct wl_listener new_input;
 	struct wl_listener inhibit_activate;
 	struct wl_listener inhibit_deactivate;
+	struct wl_listener keyboard_shortcuts_inhibit_new_inhibitor;
 	struct wl_listener virtual_keyboard_new;
 	struct wl_listener virtual_pointer_new;
 };

include/sway/input/seat.h

@@ -1,6 +1,7 @@
 #ifndef _SWAY_INPUT_SEAT_H
 #define _SWAY_INPUT_SEAT_H
 
+#include <wlr/types/wlr_keyboard_shortcuts_inhibit_v1.h>
 #include <wlr/types/wlr_layer_shell_v1.h>
 #include <wlr/types/wlr_seat.h>
 #include <wlr/util/edges.h>
@@ -94,6 +95,8 @@ struct sway_seat {
 
 	struct wl_list devices; // sway_seat_device::link
 	struct wl_list keyboard_groups; // sway_keyboard_group::link
+	struct wl_list keyboard_shortcuts_inhibitors;
+				// sway_keyboard_shortcuts_inhibitor::link
 
 	struct wl_list link; // input_manager::seats
 };
@@ -104,6 +107,14 @@ struct sway_pointer_constraint {
 	struct wl_listener destroy;
 };
 
+struct sway_keyboard_shortcuts_inhibitor {
+	struct wlr_keyboard_shortcuts_inhibitor_v1 *inhibitor;
+
+	struct wl_listener destroy;
+
+	struct wl_list link; // sway_seat::keyboard_shortcuts_inhibitors
+};
+
 struct sway_seat *seat_create(const char *seat_name);
 
 void seat_destroy(struct sway_seat *seat);
@@ -269,4 +280,11 @@ void seatop_render(struct sway_seat *seat, struct sway_output *output,
 
 bool seatop_allows_set_cursor(struct sway_seat *seat);
 
+/**
+ * Returns the keyboard shortcuts inhibitor that applies to the currently
+ * focused surface of a seat or NULL if none exists.
+ */
+struct sway_keyboard_shortcuts_inhibitor *
+keyboard_shortcuts_inhibitor_get_for_focused_surface(const struct sway_seat *seat);
+
 #endif

sway/commands/bind.c

@@ -72,7 +72,8 @@ static bool binding_key_compare(struct sway_binding *binding_a,
 	}
 
 	uint32_t conflict_generating_flags = BINDING_RELEASE | BINDING_BORDER
-			| BINDING_CONTENTS | BINDING_TITLEBAR | BINDING_LOCKED;
+			| BINDING_CONTENTS | BINDING_TITLEBAR | BINDING_LOCKED
+			| BINDING_INHIBITED;
 	if ((binding_a->flags & conflict_generating_flags) !=
 			(binding_b->flags & conflict_generating_flags)) {
 		return false;
@@ -354,6 +355,8 @@ static struct cmd_results *cmd_bindsym_or_bindcode(int argc, char **argv,
 			binding->flags |= BINDING_RELEASE;
 		} else if (strcmp("--locked", argv[0]) == 0) {
 			binding->flags |= BINDING_LOCKED;
+		} else if (strcmp("--inhibited", argv[0]) == 0) {
+			binding->flags |= BINDING_INHIBITED;
 		} else if (strcmp("--whole-window", argv[0]) == 0) {
 			binding->flags |= BINDING_BORDER | BINDING_CONTENTS | BINDING_TITLEBAR;
 		} else if (strcmp("--border", argv[0]) == 0) {

sway/input/input-manager.c

@@ -296,6 +296,46 @@ static void handle_inhibit_deactivate(struct wl_listener *listener, void *data)
 	}
 }
 
+static void handle_keyboard_shortcuts_inhibitor_destroy(
+		struct wl_listener *listener, void *data) {
+	struct sway_keyboard_shortcuts_inhibitor *sway_inhibitor =
+		wl_container_of(listener, sway_inhibitor, destroy);
+
+	sway_log(SWAY_DEBUG, "Removing keyboard shortcuts inhibitor");
+
+	// sway_seat::keyboard_shortcuts_inhibitors
+	wl_list_remove(&sway_inhibitor->link);
+	wl_list_remove(&sway_inhibitor->destroy.link);
+	free(sway_inhibitor);
+}
+
+static void handle_keyboard_shortcuts_inhibit_new_inhibitor(
+		struct wl_listener *listener, void *data) {
+	struct sway_input_manager *input_manager =
+		wl_container_of(listener, input_manager,
+				keyboard_shortcuts_inhibit_new_inhibitor);
+	struct wlr_keyboard_shortcuts_inhibitor_v1 *inhibitor = data;
+
+	sway_log(SWAY_DEBUG, "Adding keyboard shortcuts inhibitor");
+
+	struct sway_keyboard_shortcuts_inhibitor *sway_inhibitor =
+		calloc(1, sizeof(struct sway_keyboard_shortcuts_inhibitor));
+	if (!sway_assert(sway_inhibitor, "could not allocate keyboard "
+				"shortcuts inhibitor")) {
+		return;
+	}
+	sway_inhibitor->inhibitor = inhibitor;
+
+	sway_inhibitor->destroy.notify = handle_keyboard_shortcuts_inhibitor_destroy;
+	wl_signal_add(&inhibitor->events.destroy, &sway_inhibitor->destroy);
+
+	// attach inhibitor to the seat it applies to
+	struct sway_seat *seat = inhibitor->seat->data;
+	wl_list_insert(&seat->keyboard_shortcuts_inhibitors, &sway_inhibitor->link);
+
+	wlr_keyboard_shortcuts_inhibitor_v1_activate(inhibitor);
+}
+
 void handle_virtual_keyboard(struct wl_listener *listener, void *data) {
 	struct sway_input_manager *input_manager =
 		wl_container_of(listener, input_manager, virtual_keyboard_new);
@@ -397,6 +437,13 @@ struct sway_input_manager *input_manager_create(struct sway_server *server) {
 	wl_signal_add(&input->inhibit->events.deactivate,
 			&input->inhibit_deactivate);
 
+	input->keyboard_shortcuts_inhibit =
+		wlr_keyboard_shortcuts_inhibit_v1_create(server->wl_display);
+	input->keyboard_shortcuts_inhibit_new_inhibitor.notify =
+		handle_keyboard_shortcuts_inhibit_new_inhibitor;
+	wl_signal_add(&input->keyboard_shortcuts_inhibit->events.new_inhibitor,
+			&input->keyboard_shortcuts_inhibit_new_inhibitor);
+
 	return input;
 }
 

sway/input/keyboard.c

@@ -150,16 +150,18 @@ static bool update_shortcut_state(struct sway_shortcut_state *state,
  */
 static void get_active_binding(const struct sway_shortcut_state *state,
 		list_t *bindings, struct sway_binding **current_binding,
-		uint32_t modifiers, bool release, bool locked, const char *input,
+		uint32_t modifiers, bool release, bool locked, bool inhibited,
-		bool exact_input, xkb_layout_index_t group) {
+		const char *input, bool exact_input, xkb_layout_index_t group) {
 	for (int i = 0; i < bindings->length; ++i) {
 		struct sway_binding *binding = bindings->items[i];
 		bool binding_locked = (binding->flags & BINDING_LOCKED) != 0;
+		bool binding_inhibited = (binding->flags & BINDING_INHIBITED) != 0;
 		bool binding_release = binding->flags & BINDING_RELEASE;
 
 		if (modifiers ^ binding->modifiers ||
 				release != binding_release ||
 				locked > binding_locked ||
+				inhibited > binding_inhibited ||
 				(binding->group != XKB_LAYOUT_INVALID &&
 				 binding->group != group) ||
 				(strcmp(binding->input, input) != 0 &&
@@ -195,6 +197,8 @@ static void get_active_binding(const struct sway_shortcut_state *state,
 
 			bool current_locked =
 				((*current_binding)->flags & BINDING_LOCKED) != 0;
+			bool current_inhibited =
+				((*current_binding)->flags & BINDING_INHIBITED) != 0;
 			bool current_input = strcmp((*current_binding)->input, input) == 0;
 			bool current_group_set =
 				(*current_binding)->group != XKB_LAYOUT_INVALID;
@@ -203,6 +207,7 @@ static void get_active_binding(const struct sway_shortcut_state *state,
 
 			if (current_input == binding_input
 					&& current_locked == binding_locked
+					&& current_inhibited == binding_inhibited
 					&& current_group_set == binding_group_set) {
 				sway_log(SWAY_DEBUG,
 						"Encountered conflicting bindings %d and %d",
@@ -224,11 +229,21 @@ static void get_active_binding(const struct sway_shortcut_state *state,
 					current_locked == locked) {
 				continue; // Prefer correct lock state for matching input+group
 			}
+
+			if (current_input == binding_input &&
+					current_group_set == binding_group_set &&
+					current_locked == binding_locked &&
+					current_inhibited == inhibited) {
+				// Prefer correct inhibition state for matching
+				// input+group+locked
+				continue;
+			}
 		}
 
 		*current_binding = binding;
 		if (strcmp((*current_binding)->input, input) == 0 &&
 				(((*current_binding)->flags & BINDING_LOCKED) == locked) &&
+				(((*current_binding)->flags & BINDING_INHIBITED) == inhibited) &&
 				(*current_binding)->group == group) {
 			return; // If a perfect match is found, quit searching
 		}
@@ -328,6 +343,9 @@ static void handle_key_event(struct sway_keyboard *keyboard,
 	bool exact_identifier = wlr_device->keyboard->group != NULL;
 	seat_idle_notify_activity(seat, IDLE_SOURCE_KEYBOARD);
 	bool input_inhibited = seat->exclusive_client != NULL;
+	struct sway_keyboard_shortcuts_inhibitor *sway_inhibitor =
+		keyboard_shortcuts_inhibitor_get_for_focused_surface(seat);
+	bool shortcuts_inhibited = sway_inhibitor && sway_inhibitor->inhibitor->active;
 
 	// Identify new keycode, raw keysym(s), and translated keysym(s)
 	xkb_keycode_t keycode = event->keycode + 8;
@@ -364,15 +382,18 @@ static void handle_key_event(struct sway_keyboard *keyboard,
 	struct sway_binding *binding_released = NULL;
 	get_active_binding(&keyboard->state_keycodes,
 			config->current_mode->keycode_bindings, &binding_released,
-			code_modifiers, true, input_inhibited, device_identifier,
+			code_modifiers, true, input_inhibited,
+			shortcuts_inhibited, device_identifier,
 			exact_identifier, keyboard->effective_layout);
 	get_active_binding(&keyboard->state_keysyms_raw,
 			config->current_mode->keysym_bindings, &binding_released,
-			raw_modifiers, true, input_inhibited, device_identifier,
+			raw_modifiers, true, input_inhibited,
+			shortcuts_inhibited, device_identifier,
 			exact_identifier, keyboard->effective_layout);
 	get_active_binding(&keyboard->state_keysyms_translated,
 			config->current_mode->keysym_bindings, &binding_released,
-			translated_modifiers, true, input_inhibited, device_identifier,
+			translated_modifiers, true, input_inhibited,
+			shortcuts_inhibited, device_identifier,
 			exact_identifier, keyboard->effective_layout);
 
 	// Execute stored release binding once no longer active
@@ -393,17 +414,19 @@ static void handle_key_event(struct sway_keyboard *keyboard,
 	if (event->state == WLR_KEY_PRESSED) {
 		get_active_binding(&keyboard->state_keycodes,
 				config->current_mode->keycode_bindings, &binding,
-				code_modifiers, false, input_inhibited, device_identifier,
+				code_modifiers, false, input_inhibited,
+				shortcuts_inhibited, device_identifier,
 				exact_identifier, keyboard->effective_layout);
 		get_active_binding(&keyboard->state_keysyms_raw,
 				config->current_mode->keysym_bindings, &binding,
-				raw_modifiers, false, input_inhibited, device_identifier,
+				raw_modifiers, false, input_inhibited,
+				shortcuts_inhibited, device_identifier,
 				exact_identifier, keyboard->effective_layout);
 		get_active_binding(&keyboard->state_keysyms_translated,
 				config->current_mode->keysym_bindings, &binding,
 				translated_modifiers, false, input_inhibited,
-				device_identifier, exact_identifier,
+				shortcuts_inhibited, device_identifier,
-				keyboard->effective_layout);
+				exact_identifier, keyboard->effective_layout);
 	}
 
 	// Set up (or clear) keyboard repeat for a pressed binding. Since the

sway/input/seat.c

@@ -557,6 +557,7 @@ struct sway_seat *seat_create(const char *seat_name) {
 		handle_request_set_primary_selection;
 
 	wl_list_init(&seat->keyboard_groups);
+	wl_list_init(&seat->keyboard_shortcuts_inhibitors);
 
 	wl_list_insert(&server.input->seats, &seat->link);
 
@@ -1473,3 +1474,18 @@ void seatop_render(struct sway_seat *seat, struct sway_output *output,
 bool seatop_allows_set_cursor(struct sway_seat *seat) {
 	return seat->seatop_impl->allow_set_cursor;
 }
+
+struct sway_keyboard_shortcuts_inhibitor *
+keyboard_shortcuts_inhibitor_get_for_focused_surface(
+		const struct sway_seat *seat) {
+	struct wlr_surface *focused_surface =
+		seat->wlr_seat->keyboard_state.focused_surface;
+	struct sway_keyboard_shortcuts_inhibitor *sway_inhibitor = NULL;
+	wl_list_for_each(sway_inhibitor, &seat->keyboard_shortcuts_inhibitors, link) {
+		if (sway_inhibitor->inhibitor->surface == focused_surface) {
+			return sway_inhibitor;
+		}
+	}
+
+	return NULL;
+}

sway/sway.5.scd

@@ -374,6 +374,14 @@ runtime.
 	and one has both _--input-device_ and _--locked_ and the other has neither,
 	the former will be preferred even when unlocked.
 
+	Unless the flag _--inhibited_ is set, the command will not be run when
+	a keyboard shortcuts inhibitor is active for the currently focused
+	window. Such inhibitors are usually requested by remote desktop and
+	virtualization software to enable the user to send keyboard shortcuts
+	to the remote or virtual session. The _--inhibited_ flag allows to
+	define bindings which will be exempt from pass-through to such
+	software. The same preference logic as for _--locked_ applies.
+
 	Bindings to keysyms are layout-dependent. This can be changed with the
 	_--to-code_ flag. In this case, the keysyms will be translated into the
 	corresponding keycodes in the first configured layout.