ipc: add an input event

This adds an ipc event related to input devices. Currently the
following changes are supported:
- added: when an input device becomes available
- removed: when an input device is no longer available
- xkb_keymap_changed: (keyboards only) the keymap changed
- xkb_layout_changed: (keyboards only) the effective layout changed

7 files changed, 107 insertions, 0 deletions

diff --git a/include/ipc.h b/include/ipc.h
index 6063f69c..7ae21ab3 100644
--- a/include/ipc.h
+++ b/include/ipc.h
@@ -34,6 +34,7 @@ enum ipc_command_type {
 
         // sway-specific event types
         IPC_EVENT_BAR_STATE_UPDATE = ((1<<31) | 20),
+        IPC_EVENT_INPUT = ((1<<31) | 21),
 };
 
 #endif
diff --git a/include/sway/input/keyboard.h b/include/sway/input/keyboard.h
index 90214af9..1ff63c94 100644
--- a/include/sway/input/keyboard.h
+++ b/include/sway/input/keyboard.h
@@ -52,6 +52,7 @@ struct sway_keyboard {
         struct sway_seat_device *seat_device;
 
         struct xkb_keymap *keymap;
+        xkb_layout_index_t effective_layout;
 
         struct wl_listener keyboard_key;
         struct wl_listener keyboard_modifiers;
diff --git a/include/sway/ipc-server.h b/include/sway/ipc-server.h
index 3c43f74d..bc4f781a 100644
--- a/include/sway/ipc-server.h
+++ b/include/sway/ipc-server.h
@@ -2,6 +2,7 @@
 #define _SWAY_IPC_SERVER_H
 #include <sys/socket.h>
 #include "sway/config.h"
+#include "sway/input/input-manager.h"
 #include "sway/tree/container.h"
 #include "ipc.h"
 
@@ -19,5 +20,6 @@ void ipc_event_bar_state_update(struct bar_config *bar);
 void ipc_event_mode(const char *mode, bool pango);
 void ipc_event_shutdown(const char *reason);
 void ipc_event_binding(struct sway_binding *binding);
+void ipc_event_input(const char *change, struct sway_input_device *device);
 
 #endif
diff --git a/sway/input/input-manager.c b/sway/input/input-manager.c
index 4fd980c4..dd84a0b3 100644
--- a/sway/input/input-manager.c
+++ b/sway/input/input-manager.c
@@ -12,6 +12,7 @@
 #include "sway/config.h"
 #include "sway/input/input-manager.h"
 #include "sway/input/seat.h"
+#include "sway/ipc-server.h"
 #include "sway/server.h"
 #include "stringop.h"
 #include "list.h"
@@ -584,6 +585,8 @@ static void handle_device_destroy(struct wl_listener *listener, void *data) {
                 seat_remove_device(seat, input_device);
         }
 
+        ipc_event_input("removed", input_device);
+
         wl_list_remove(&input_device->link);
         wl_list_remove(&input_device->device_destroy.link);
         free(input_device->identifier);
@@ -656,6 +659,8 @@ static void handle_new_input(struct wl_listener *listener, void *data) {
                         "device '%s' is not configured on any seats",
                         input_device->identifier);
         }
+
+        ipc_event_input("added", input_device);
 }
 
 static void handle_inhibit_activate(struct wl_listener *listener, void *data) {
diff --git a/sway/input/keyboard.c b/sway/input/keyboard.c
index 1f7ed849..328458fa 100644
--- a/sway/input/keyboard.c
+++ b/sway/input/keyboard.c
@@ -473,6 +473,11 @@ static void handle_keyboard_modifiers(struct wl_listener *listener,
 
         uint32_t modifiers = wlr_keyboard_get_modifiers(wlr_device->keyboard);
         determine_bar_visibility(modifiers);
+
+        if (wlr_device->keyboard->modifiers.group != keyboard->effective_layout) {
+                keyboard->effective_layout = wlr_device->keyboard->modifiers.group;
+                ipc_event_input("xkb_layout", keyboard->seat_device->input_device);
+        }
 }
 
 struct sway_keyboard *sway_keyboard_create(struct sway_seat *seat,
@@ -603,8 +608,23 @@ void sway_keyboard_configure(struct sway_keyboard *keyboard) {
                 }
         }
 
+        bool keymap_changed = false;
+        bool effective_layout_changed = keyboard->effective_layout != 0;
+        if (keyboard->keymap) {
+                char *old_keymap_string = xkb_keymap_get_as_string(keyboard->keymap,
+                        XKB_KEYMAP_FORMAT_TEXT_V1);
+                char *new_keymap_string = xkb_keymap_get_as_string(keymap,
+                        XKB_KEYMAP_FORMAT_TEXT_V1);
+                keymap_changed = strcmp(old_keymap_string, new_keymap_string);
+                free(old_keymap_string);
+                free(new_keymap_string);
+        } else {
+                keymap_changed = true;
+        }
+
         xkb_keymap_unref(keyboard->keymap);
         keyboard->keymap = keymap;
+        keyboard->effective_layout = 0;
         wlr_keyboard_set_keymap(wlr_device->keyboard, keyboard->keymap);
 
         xkb_mod_mask_t locked_mods = 0;
@@ -654,6 +674,14 @@ void sway_keyboard_configure(struct sway_keyboard *keyboard) {
         wl_signal_add(&wlr_device->keyboard->events.modifiers,
                 &keyboard->keyboard_modifiers);
         keyboard->keyboard_modifiers.notify = handle_keyboard_modifiers;
+
+        if (keymap_changed) {
+                ipc_event_input("xkb_keymap",
+                        keyboard->seat_device->input_device);
+        } else if (effective_layout_changed) {
+                ipc_event_input("xkb_layout",
+                        keyboard->seat_device->input_device);
+        }
 }
 
 void sway_keyboard_destroy(struct sway_keyboard *keyboard) {
diff --git a/sway/ipc-server.c b/sway/ipc-server.c
index ca1c1b12..773e90fd 100644
--- a/sway/ipc-server.c
+++ b/sway/ipc-server.c
@@ -487,6 +487,21 @@ static void ipc_event_tick(const char *payload) {
         json_object_put(json);
 }
 
+void ipc_event_input(const char *change, struct sway_input_device *device) {
+        if (!ipc_has_event_listeners(IPC_EVENT_INPUT)) {
+                return;
+        }
+        sway_log(SWAY_DEBUG, "Sending input event");
+
+        json_object *json = json_object_new_object();
+        json_object_object_add(json, "change", json_object_new_string(change));
+        json_object_object_add(json, "input", ipc_json_describe_input(device));
+
+        const char *json_string = json_object_to_json_string(json);
+        ipc_send_event(json_string, IPC_EVENT_INPUT);
+        json_object_put(json);
+}
+
 int ipc_client_handle_writable(int client_fd, uint32_t mask, void *data) {
         struct ipc_client *client = data;
 
@@ -716,6 +731,8 @@ void ipc_client_handle_command(struct ipc_client *client, uint32_t payload_lengt
                         } else if (strcmp(event_type, "tick") == 0) {
                                 client->subscribed_events |= event_mask(IPC_EVENT_TICK);
                                 is_tick = true;
+                        } else if (strcmp(event_type, "input") == 0) {
+                                client->subscribed_events |= event_mask(IPC_EVENT_INPUT);
                         } else {
                                 const char msg[] = "{\"success\": false}";
                                 ipc_send_reply(client, payload_type, msg, strlen(msg));
diff --git a/sway/sway-ipc.7.scd b/sway/sway-ipc.7.scd
index 3657dcd6..4688e46d 100644
--- a/sway/sway-ipc.7.scd
+++ b/sway/sway-ipc.7.scd
@@ -1371,6 +1371,9 @@ available:
 |- 0x80000014
 :  bar_status_update
 :  Send when the visibility of a bar should change due to a modifier
+|- 0x80000015
+:  input
+:  Sent when something related to input devices changes
 
 
 ## 0x80000000. WORKSPACE
@@ -1702,6 +1705,56 @@ event is a single object with the following properties:
 }
 ```
 
+## 0x80000015. INPUT
+
+Sent when something related to the input devices changes. The event is a single
+object with the following properties:
+
+[- *PROPERTY*
+:- *DATA TYPE*
+:- *DESCRIPTION*
+|- change
+:  string
+:[ What has changed
+|- input
+:  object
+:  An object representing the input that is identical the ones GET_INPUTS gives
+
+The following change types are currently available:
+[- *TYPE*
+:- *DESCRIPTION*
+|- added
+:[ The input device became available
+|- removed
+:  The input device is no longer available
+|- xkb_keymap
+:  (Keyboards only) The keymap for the keyboard has changed
+|- xkb_layout
+:  (Keyboards only) The effective layout in the keymap has changed
+
+*Example Event:*
+```
+{
+        "change": "xkb_layout",
+        "input": {
+                "identifier": "1:1:AT_Translated_Set_2_keyboard",
+                "name": "AT Translated Set 2 keyboard",
+                "vendor": 1,
+                "product": 1,
+                "type": "keyboard",
+                "xkb_layout_names": [
+                        "English (US)",
+                        "English (Dvorak)"
+                ],
+                "xkb_active_layout_index": 1,
+                "xkb_active_layout_name": "English (Dvorak)",
+                "libinput": {
+                        "send_events": "enabled"
+                }
+        }
+}
+```
+
 # SEE ALSO
 
 *sway*(1) *sway*(5) *sway-bar*(5) *swaymsg*(1) *sway-input*(5) *sway-output*(5)