Added some escape-hatch keybindings for Wetterhorn.

Specifically a way to reload the plugin and switch vterms. This is
important in case the plugin is borked and stops accepting keyboard, the
user can switch to a vterm, fix the plugin and reload it to get things
working again without running into data loss.

4 files changed, 43 insertions, 12 deletions

diff --git a/Setup.hs b/Setup.hs
index 50385ed..f3a2180 100644
--- a/Setup.hs
+++ b/Setup.hs
@@ -19,7 +19,7 @@ main = do
           let buildPath = fromJust (flagToMaybe $ configDistPref conf)
 
           callCommand $
-            printf "cd wlroots && meson setup %s -Dexamples=false --reconfigure"  (wlrootsDir buildPath)
+            printf "cd wlroots && meson setup %s -Dexamples=false -Dbackends=x11,drm,libinput --reconfigure"  (wlrootsDir buildPath)
 
           callCommand $
             printf "cmake -B %s -S harness"  (harnessDir buildPath)
diff --git a/harness/include/wl.h b/harness/include/wl.h
index b8d4e14..903ba10 100644
--- a/harness/include/wl.h
+++ b/harness/include/wl.h
@@ -6,10 +6,11 @@
 #include <unistd.h>
 #include <wayland-server-core.h>
 #include <wlr/backend.h>
+#include <wlr/backend/session.h>
 #include <wlr/render/allocator.h>
 #include <wlr/render/wlr_renderer.h>
-#include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_data_device.h>
 #include <wlr/types/wlr_input_device.h>
 #include <wlr/types/wlr_keyboard.h>
@@ -68,6 +69,7 @@ struct tinywl_server {
 	struct wl_list outputs;
 	struct wl_listener new_output;
 
+  struct wlr_session *session;
   plugin_t plugin;
 };
 
diff --git a/harness/src/wl.c b/harness/src/wl.c
index 0bd0410..f083a5e 100644
--- a/harness/src/wl.c
+++ b/harness/src/wl.c
@@ -105,15 +105,43 @@ static void keyboard_handle_key(struct wl_listener *listener, void *data)
   int handled = false;
   uint32_t modifiers = wlr_keyboard_get_modifiers(keyboard->wlr_keyboard);
   uint32_t codepoint;
-  /* Pass the information along to the plugin for the plugin to handle. The
-   * plugin will return via 'handled' whether or not the key event was handled
-   * or not. */
-  if (nsyms > 0) {
-    codepoint =
-        xkb_state_key_get_utf32(keyboard->wlr_keyboard->xkb_state, keycode);
-    plugin_call_update_state(server->plugin, plugin_handle_keybinding,
-                             keyboard->wlr_keyboard, event, modifiers, syms[0],
-                             codepoint, &handled);
+  int ec;
+
+  if (nsyms > 0 && syms[0] >= XKB_KEY_XF86Switch_VT_1 &&
+      syms[0] <= XKB_KEY_XF86Switch_VT_12) {
+    /* Escape-hatch to change sessions. These should always be available key
+     * bindings regardless of what the plugin dictates. This allows an escape
+     * hatch to edit the plugin in a different vterm and then use the escape
+     * hatch below to hot-restart the plugin if things get borked. */
+    if (event->state == WL_KEYBOARD_KEY_STATE_PRESSED) {
+      wlr_session_change_vt(server->session,
+                            syms[0] - XKB_KEY_XF86Switch_VT_1 + 1);
+    }
+  }
+  else if (modifiers ==
+               (WLR_MODIFIER_SHIFT | WLR_MODIFIER_CTRL | WLR_MODIFIER_ALT) &&
+           nsyms > 0 && syms[0] == XKB_KEY_Escape) {
+    /* Escape-hatch to hot-reload the plugin in case the plugin got borked and
+     * stops accepting keybindings. Ctrl+Shift+Alt+Escape will always reload the
+     * plugin.*/
+    if (event->state == WL_KEYBOARD_KEY_STATE_PRESSED) {
+      if ((ec = plugin_hot_reload_same_state(&server->plugin)) != 0) {
+        fprintf(stderr, "Failed to hot reload plugin");
+        exit(1);
+      }
+    }
+  }
+  else {
+    /* Pass the information along to the plugin for the plugin to handle. The
+     * plugin will return via 'handled' whether or not the key event was handled
+     * or not. */
+    if (nsyms > 0) {
+      codepoint =
+          xkb_state_key_get_utf32(keyboard->wlr_keyboard->xkb_state, keycode);
+      plugin_call_update_state(server->plugin, plugin_handle_keybinding,
+                               keyboard->wlr_keyboard, event, modifiers,
+                               syms[0], codepoint, &handled);
+    }
   }
 }
 
@@ -806,7 +834,7 @@ int main(int argc, char *argv[])
    * output hardware. The autocreate option will choose the most suitable
    * backend based on the current environment, such as opening an X11 window
    * if an X11 server is running. */
-  server.backend = wlr_backend_autocreate(server.wl_display, NULL);
+  server.backend = wlr_backend_autocreate(server.wl_display, &server.session);
   if (server.backend == NULL) {
     wlr_log(WLR_ERROR, "failed to create wlr_backend");
     return 1;
diff --git a/src/Wetterhorn/Core/W.hs b/src/Wetterhorn/Core/W.hs
index b809545..b2c6b51 100644
--- a/src/Wetterhorn/Core/W.hs
+++ b/src/Wetterhorn/Core/W.hs
@@ -224,6 +224,7 @@ shellExec = wio . ForeignInterface.doShellExec
 wio :: IO a -> W a
 wio = liftIO
 
+-- | Type class to lift an arbitrary 'W' computation into another monad.
 class Wlike m where
   liftW :: W a -> m a