From 0f8d8bcf15dc8c84e984f07e411b331c961dd0a6 Mon Sep 17 00:00:00 2001
From: Kirill Chibisov <contact@kchibisov.com>
Date: Sun, 9 Oct 2022 09:55:19 +0300
Subject: [PATCH] On X11, fix IME crashing without available styles

Fixes #2510.
---
 CHANGELOG.md                                  |  4 +-
 .../linux/x11/ime/input_method.rs             | 54 ++++++++++---------
 src/platform_impl/linux/x11/ime/mod.rs        |  8 +--
 3 files changed, 37 insertions(+), 29 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 61c402060a3..fedbe852d58 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,9 @@ And please only add new entries to the top of this list, right below the `# Unre
 
 # Unreleased
 
-# 0.27.3 (2022-9-10)
+- On X11, fix XIM not picking IME when no styles advertised.
+
+# 0.27.3
 
 - On Windows, added `WindowExtWindows::set_undecorated_shadow` and `WindowBuilderExtWindows::with_undecorated_shadow` to draw the drop shadow behind a borderless window.
 - On Windows, fixed default window features (ie snap, animations, shake, etc.) when decorations are disabled.
diff --git a/src/platform_impl/linux/x11/ime/input_method.rs b/src/platform_impl/linux/x11/ime/input_method.rs
index ca78a1bdabf..cb9da36a4dc 100644
--- a/src/platform_impl/linux/x11/ime/input_method.rs
+++ b/src/platform_impl/linux/x11/ime/input_method.rs
@@ -41,26 +41,36 @@ unsafe fn open_im(xconn: &Arc<XConnection>, locale_modifiers: &CStr) -> Option<f
 #[derive(Debug)]
 pub struct InputMethod {
     pub im: ffi::XIM,
-    pub preedit_style: Style,
-    pub none_style: Style,
     _name: String,
 }
 
+#[derive(Debug, Default)]
+pub struct InputMethodStyles {
+    pub preedit_style: Option<Style>,
+    pub none_style: Option<Style>,
+}
+
 impl InputMethod {
-    fn new(xconn: &Arc<XConnection>, im: ffi::XIM, name: String) -> Option<Self> {
+    fn new(im: ffi::XIM, name: String) -> Self {
+        Self { im, _name: name }
+    }
+
+    // XXX checking this during creation is not desired, since we don't want to filter
+    // ime based on styles since IME could be reloading, etc, so we ask for that when needed.
+    pub(crate) fn query_styles(&self, xconn: &Arc<XConnection>) -> InputMethodStyles {
         let mut styles: *mut XIMStyles = std::ptr::null_mut();
 
         // Query the styles supported by the XIM.
         unsafe {
             if !(xconn.xlib.XGetIMValues)(
-                im,
+                self.im,
                 ffi::XNQueryInputStyle_0.as_ptr() as *const _,
                 (&mut styles) as *mut _,
                 std::ptr::null_mut::<()>(),
             )
             .is_null()
             {
-                return None;
+                return InputMethodStyles::default();
             }
         }
 
@@ -70,33 +80,27 @@ impl InputMethod {
         unsafe {
             std::slice::from_raw_parts((*styles).supported_styles, (*styles).count_styles as _)
                 .iter()
-                .for_each(|style| match *style {
-                    XIM_PREEDIT_STYLE => {
-                        preedit_style = Some(Style::Preedit(*style));
-                    }
-                    XIM_NOTHING_STYLE if preedit_style.is_none() => {
-                        preedit_style = Some(Style::Nothing(*style))
+                .for_each(|style| {
+                    println!("{style:x}");
+                    match *style {
+                        XIM_PREEDIT_STYLE => {
+                            preedit_style = Some(Style::Preedit(*style));
+                        }
+                        XIM_NOTHING_STYLE if preedit_style.is_none() => {
+                            preedit_style = Some(Style::Nothing(*style))
+                        }
+                        XIM_NONE_STYLE => none_style = Some(Style::None(*style)),
+                        _ => (),
                     }
-                    XIM_NONE_STYLE => none_style = Some(Style::None(*style)),
-                    _ => (),
                 });
 
             (xconn.xlib.XFree)(styles.cast());
         };
 
-        if preedit_style.is_none() && none_style.is_none() {
-            return None;
-        }
-
-        let preedit_style = preedit_style.unwrap_or_else(|| none_style.unwrap());
-        let none_style = none_style.unwrap_or(preedit_style);
-
-        Some(InputMethod {
-            im,
-            _name: name,
+        InputMethodStyles {
             preedit_style,
             none_style,
-        })
+        }
     }
 }
 
@@ -257,7 +261,7 @@ impl PotentialInputMethod {
     pub fn open_im(&mut self, xconn: &Arc<XConnection>) -> Option<InputMethod> {
         let im = unsafe { open_im(xconn, &self.name.c_string) };
         self.successful = Some(im.is_some());
-        im.and_then(|im| InputMethod::new(xconn, im, self.name.string.clone()))
+        im.map(|im| InputMethod::new(im, self.name.string.clone()))
     }
 }
 
diff --git a/src/platform_impl/linux/x11/ime/mod.rs b/src/platform_impl/linux/x11/ime/mod.rs
index fec2423a35a..8ff6c34e846 100644
--- a/src/platform_impl/linux/x11/ime/mod.rs
+++ b/src/platform_impl/linux/x11/ime/mod.rs
@@ -122,11 +122,13 @@ impl Ime {
             None
         } else {
             let im = self.inner.im.as_ref().unwrap();
+            let styles = im.query_styles(&self.inner.xconn);
             let style = if with_preedit {
-                im.preedit_style
+                styles.preedit_style.or(styles.none_style)
             } else {
-                im.none_style
-            };
+                styles.none_style.or(styles.preedit_style)
+            }
+            .unwrap_or_default();
 
             let context = unsafe {
                 ImeContext::new(