implement an emit command and resolve swaywm#4937

Command Syntax: emit <press|release|press-release> <criteria> <keys>
* action: specifies whether to press, release the keys or do both
* criteria: first window that matches the criteria will get the key input
* keys: modifiers and keys separated by +
Examples:
* emit press-release [app_id=com.obsproject.Studio] ALT+F8
* bindsym --no-repeat Ctrl+T emit press [app_id=wev] Ctrl+A
* bindsym --no-repeat --release Ctrl+T emit release [app_id=wev] Ctrl+A

common/util.c

@@ -141,3 +141,9 @@ bool sway_set_cloexec(int fd, bool cloexec) {
 	}
 	return true;
 }
+
+uint32_t get_current_time_msec(void) {
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+	return now.tv_sec * 1000 + now.tv_nsec / 1000000;
+}

include/sway/commands.h

@@ -201,6 +201,7 @@ sway_cmd cmd_workspace;
 sway_cmd cmd_workspace_layout;
 sway_cmd cmd_ws_auto_back_and_forth;
 sway_cmd cmd_xwayland;
+sway_cmd cmd_emit;
 
 sway_cmd bar_cmd_bindcode;
 sway_cmd bar_cmd_binding_mode_indicator;

include/util.h

@@ -61,4 +61,6 @@ const char *sway_wl_output_subpixel_to_string(enum wl_output_subpixel subpixel);
 
 bool sway_set_cloexec(int fd, bool cloexec);
 
+uint32_t get_current_time_msec(void);
+
 #endif

sway/commands.c

@@ -115,6 +115,7 @@ static const struct cmd_handler command_handlers[] = {
 	{ "allow_tearing", cmd_allow_tearing },
 	{ "border", cmd_border },
 	{ "create_output", cmd_create_output },
+	{ "emit", cmd_emit },
 	{ "exit", cmd_exit },
 	{ "floating", cmd_floating },
 	{ "fullscreen", cmd_fullscreen },

sway/commands/emit.c

@@ -0,0 +1,170 @@
+#include "list.h"
+#include "sway/commands.h"
+#include "sway/criteria.h"
+#include "sway/input/keyboard.h"
+#include "sway/input/seat.h"
+#include "sway/tree/container.h"
+#include "stringop.h"
+
+
+struct keycode_matches {
+	xkb_keysym_t keysym;
+	xkb_keycode_t keycode;
+	int count;
+};
+
+static void find_keycode(struct xkb_keymap *keymap,
+		xkb_keycode_t keycode, void *data) {
+	xkb_keysym_t keysym = xkb_state_key_get_one_sym(
+			config->keysym_translation_state, keycode);
+
+	if (keysym == XKB_KEY_NoSymbol) {
+		return;
+	}
+
+	struct keycode_matches *matches = data;
+	if (matches->keysym == keysym) {
+		matches->keycode = keycode;
+		matches->count++;
+	}
+}
+
+static struct keycode_matches get_keycode_for_keysym(xkb_keysym_t keysym) {
+	struct keycode_matches matches = {
+		.keysym = keysym,
+		.keycode = XKB_KEYCODE_INVALID,
+		.count = 0,
+	};
+
+	xkb_keymap_key_for_each(
+			xkb_state_get_keymap(config->keysym_translation_state),
+			find_keycode, &matches);
+	return matches;
+}
+
+enum emit_action {
+  EMIT_ACTION_RELEASE = 1 << 0,
+  EMIT_ACTION_PRESS = 1 << 1
+};
+
+
+struct cmd_results *cmd_emit(int argc, char **argv) {
+  struct cmd_results *error = NULL;
+  if((error = checkarg(argc, "emit", EXPECTED_EQUAL_TO, 3))) {
+    return error;
+  }
+
+  enum emit_action action = 0;
+  if(strcmp("press", argv[0]) == 0) {
+    action = EMIT_ACTION_PRESS;
+  } else if(strcmp("release", argv[0]) == 0) {
+    action = EMIT_ACTION_RELEASE;
+  } else if(strcmp("press-release", argv[0]) == 0) {
+    action = EMIT_ACTION_PRESS | EMIT_ACTION_RELEASE;
+  }
+
+  if(!action) {
+    return cmd_results_new(CMD_INVALID, "Unknown emit action '%s'", argv[0]);
+  }
+
+
+  char *err_str = NULL;
+  struct criteria *criteria = criteria_parse(argv[1], &err_str);
+  if(!criteria) {
+    error = cmd_results_new(CMD_INVALID, "%s", err_str);
+    free(err_str);
+    return error;
+  }
+
+  list_t *keycodes = create_list();
+  list_t *split = split_string(argv[2], "+");
+
+  uint32_t raw_modifiers = 0;
+  for(int i = 0; i < split->length; i++) {
+    uint32_t current_mod;
+
+    // parse modifier key
+    if((current_mod = get_modifier_mask_by_name(split->items[i])) > 0) {
+      raw_modifiers |= current_mod;
+      continue;
+    }
+
+    xkb_keysym_t keysym = xkb_keysym_from_name(split->items[i],
+                                               XKB_KEYSYM_CASE_INSENSITIVE);
+    if(!keysym) {
+      criteria_destroy(criteria);
+      list_free_items_and_destroy(keycodes);
+      error = cmd_results_new(CMD_FAILURE,
+                              "Unknown key '%s'", (char*) split->items[i]);
+      list_free_items_and_destroy(split);
+      return error;
+    }
+
+    struct keycode_matches matches = get_keycode_for_keysym(keysym);
+    if(matches.count == 0) {
+      criteria_destroy(criteria);
+      list_free_items_and_destroy(keycodes);
+      list_free_items_and_destroy(split);
+      return cmd_results_new(CMD_FAILURE, "Unable to convert key to keycode");
+    }
+
+    uint32_t *keycode = malloc(sizeof(uint32_t));
+    if(!keycode) {
+      criteria_destroy(criteria);
+      list_free_items_and_destroy(keycodes);
+      list_free_items_and_destroy(split);
+      return cmd_results_new(CMD_FAILURE, "Unable to allocate key");
+    }
+    *keycode = matches.keycode;
+    list_add(keycodes, keycode);
+  }
+
+
+  list_t *containers = criteria_get_containers(criteria);
+
+  struct sway_seat *seat = config->handler_context.seat;
+  struct sway_container *original_container = seat_get_focused_container(seat);
+
+  if(containers->length == 0) {
+    return cmd_results_new(CMD_FAILURE, "no matching container found: %s", argv[1]);
+  }
+  struct sway_container *container = containers->items[0];
+  bool is_same_surface = container->view->surface == original_container->view->surface;
+
+  if(!is_same_surface) {
+    wlr_seat_keyboard_enter(seat->wlr_seat, container->view->surface, 0, 0, NULL);
+  }
+
+  struct wlr_keyboard_modifiers wlr_modifiers = {
+    .depressed = raw_modifiers
+  };
+  wlr_seat_keyboard_send_modifiers(seat->wlr_seat, &wlr_modifiers);
+
+  // send key presses
+  if(action & EMIT_ACTION_PRESS) {
+    for(int i = 0; i < keycodes->length; i++) {
+      wlr_seat_keyboard_notify_key(seat->wlr_seat, get_current_time_msec(), *((uint32_t*) keycodes->items[i])-8, 1);
+    }
+  }
+
+  // send key releases
+  if(action & EMIT_ACTION_RELEASE) {
+    for(int i = 0; i < keycodes->length; i++) {
+      wlr_seat_keyboard_notify_key(seat->wlr_seat, get_current_time_msec(), *((uint32_t*) keycodes->items[i])-8, 0);
+    }
+  }
+
+  struct wlr_keyboard *keyboard = wlr_seat_get_keyboard(seat->wlr_seat);
+
+  if(is_same_surface) {
+    wlr_seat_keyboard_send_modifiers(seat->wlr_seat, &keyboard->modifiers);
+  } else {
+    wlr_seat_keyboard_enter(seat->wlr_seat, original_container->view->surface, keyboard->keycodes, keyboard->num_keycodes, &keyboard->modifiers);
+  }
+
+  list_free(containers);
+
+  criteria_destroy(criteria);
+
+  return cmd_results_new(CMD_SUCCESS, NULL);
+}

sway/input/cursor.c

@@ -32,12 +32,6 @@
 #include "sway/tree/workspace.h"
 #include "wlr-layer-shell-unstable-v1-protocol.h"
 
-static uint32_t get_current_time_msec(void) {
-	struct timespec now;
-	clock_gettime(CLOCK_MONOTONIC, &now);
-	return now.tv_sec * 1000 + now.tv_nsec / 1000000;
-}
-
 /**
  * Returns the node at the cursor's position. If there is a surface at that
  * location, it is stored in **surface (it may not be a view).

sway/meson.build

@@ -124,6 +124,7 @@ sway_sources = files(
 	'commands/workspace_layout.c',
 	'commands/ws_auto_back_and_forth.c',
 	'commands/xwayland.c',
+	'commands/emit.c',
 
 	'commands/bar/bind.c',
 	'commands/bar/binding_mode_indicator.c',