From 00fe65630e8dc056dd28770f5691ea8ae34b6fbc Mon Sep 17 00:00:00 2001
From: Kirill Chibisov <contact@kchibisov.com>
Date: Tue, 13 Feb 2024 07:49:58 +0400
Subject: [PATCH] On X11, don't require XIM to be present

In general, we may want to use xinput v2 for keyboard input in such
cases, so we have compose going, but for now just don't crash if
there's no XIM.
---
 CHANGELOG.md                                  |  1 +
 .../linux/x11/event_processor.rs              | 39 ++++++++++++-------
 src/platform_impl/linux/x11/mod.rs            | 18 +++++----
 src/platform_impl/linux/x11/window.rs         |  6 +--
 4 files changed, 39 insertions(+), 25 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85df38c4a..63bda55af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ Unreleased` header.
 
 # Unreleased
 
+- On X11, don't require XIM to run.
 - Fix compatibility with 32-bit platforms without 64-bit atomics.
 - On macOS, fix incorrect IME cursor rect origin.
 - On X11, fix swapped instance and general class names.
diff --git a/src/platform_impl/linux/x11/event_processor.rs b/src/platform_impl/linux/x11/event_processor.rs
index 872867e83..c92e902a9 100644
--- a/src/platform_impl/linux/x11/event_processor.rs
+++ b/src/platform_impl/linux/x11/event_processor.rs
@@ -74,7 +74,11 @@ impl<T: 'static> EventProcessor<T> {
 
         // Handle IME requests.
         while let Ok(request) = self.ime_receiver.try_recv() {
-            let ime = window_target.ime.get_mut();
+            let ime = match window_target.ime.as_mut() {
+                Some(ime) => ime,
+                None => continue,
+            };
+            let ime = ime.get_mut();
             match request {
                 ImeRequest::Position(window_id, x, y) => {
                     ime.send_xim_spot(window_id, x, y);
@@ -792,10 +796,11 @@ impl<T: 'static> EventProcessor<T> {
 
         // Since all XIM stuff needs to happen from the same thread, we destroy the input
         // context here instead of when dropping the window.
-        wt.ime
-            .borrow_mut()
-            .remove_context(window as XWindow)
-            .expect("Failed to destroy input context");
+        if let Some(ime) = wt.ime.as_ref() {
+            ime.borrow_mut()
+                .remove_context(window as XWindow)
+                .expect("Failed to destroy input context");
+        }
 
         callback(
             &self.target,
@@ -918,7 +923,11 @@ impl<T: 'static> EventProcessor<T> {
                     },
                 },
             );
-        } else if let Some(ic) = wt.ime.borrow().get_context(window as XWindow) {
+        } else if let Some(ic) = wt
+            .ime
+            .as_ref()
+            .and_then(|ime| ime.borrow().get_context(window as XWindow))
+        {
             let written = wt.xconn.lookup_utf8(ic, xev);
             if !written.is_empty() {
                 let event = Event::WindowEvent {
@@ -1183,10 +1192,11 @@ impl<T: 'static> EventProcessor<T> {
         // Set the timestamp.
         wt.xconn.set_timestamp(xev.time as xproto::Timestamp);
 
-        wt.ime
-            .borrow_mut()
-            .focus(xev.event)
-            .expect("Failed to focus input context");
+        if let Some(ime) = wt.ime.as_ref() {
+            ime.borrow_mut()
+                .focus(xev.event)
+                .expect("Failed to focus input context");
+        }
 
         if self.active_window == Some(window) {
             return;
@@ -1254,10 +1264,11 @@ impl<T: 'static> EventProcessor<T> {
             return;
         }
 
-        wt.ime
-            .borrow_mut()
-            .unfocus(xev.event)
-            .expect("Failed to unfocus input context");
+        if let Some(ime) = wt.ime.as_ref() {
+            ime.borrow_mut()
+                .unfocus(xev.event)
+                .expect("Failed to unfocus input context");
+        }
 
         if self.active_window.take() == Some(window) {
             let window_id = mkwid(window);
diff --git a/src/platform_impl/linux/x11/mod.rs b/src/platform_impl/linux/x11/mod.rs
index 7078cc505..5d0ad53c8 100644
--- a/src/platform_impl/linux/x11/mod.rs
+++ b/src/platform_impl/linux/x11/mod.rs
@@ -136,7 +136,7 @@ pub struct EventLoopWindowTarget<T> {
     control_flow: Cell<ControlFlow>,
     exit: Cell<Option<i32>>,
     root: xproto::Window,
-    ime: RefCell<Ime>,
+    ime: Option<RefCell<Ime>>,
     windows: RefCell<HashMap<WindowId, Weak<UnownedWindow>>>,
     redraw_sender: WakeSender<WindowId>,
     activation_sender: WakeSender<ActivationToken>,
@@ -213,13 +213,15 @@ impl<T: 'static> EventLoop<T> {
                 setlocale(LC_CTYPE, default_locale);
             }
         }
-        let ime = RefCell::new({
-            let result = Ime::new(Arc::clone(&xconn), ime_event_sender);
-            if let Err(ImeCreationError::OpenFailure(ref state)) = result {
-                panic!("Failed to open input method: {state:#?}");
-            }
-            result.expect("Failed to set input method destruction callback")
-        });
+
+        let ime = Ime::new(Arc::clone(&xconn), ime_event_sender);
+        if let Err(ImeCreationError::OpenFailure(state)) = ime.as_ref() {
+            warn!("Failed to open input method: {state:#?}");
+        } else if let Err(err) = ime.as_ref() {
+            warn!("Failed to set input method destruction callback: {err:?}");
+        }
+
+        let ime = ime.ok().map(RefCell::new);
 
         let randr_event_offset = xconn
             .select_xrandr_input(root)
diff --git a/src/platform_impl/linux/x11/window.rs b/src/platform_impl/linux/x11/window.rs
index 42119534f..9197b4f00 100644
--- a/src/platform_impl/linux/x11/window.rs
+++ b/src/platform_impl/linux/x11/window.rs
@@ -541,9 +541,9 @@ impl UnownedWindow {
             leap!(xconn.select_xinput_events(window.xwindow, super::ALL_MASTER_DEVICES, mask))
                 .ignore_error();
 
-            {
-                let result = event_loop
-                    .ime
+            // Try to create input context for the window.
+            if let Some(ime) = event_loop.ime.as_ref() {
+                let result = ime
                     .borrow_mut()
                     .create_context(window.xwindow as ffi::Window, false);
                 leap!(result);