On X11, use events modifiers to detect state

While there's a separate event to deliver modifiers for keyboard,
unfortunately, it's not even remotely reflects the modifiers state.

Thus use events along side regular modifier updates to correctly
detect the state. Also, apply the modifiers from the regular
key event by converting their state to xkb modifiers state.

Links: alacritty/alacritty#7549
Closes: #3388

CHANGELOG.md

@@ -12,6 +12,7 @@ Unreleased` header.
 # Unreleased
 
 - On X11, don't require XIM to run.
+- On X11, fix xkb state not being updated correctly sometimes leading to wrong input.
 - 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.

Cargo.toml

@@ -167,7 +167,7 @@ wayland-protocols = { version = "0.31.0", features = [ "staging"], optional = tr
 wayland-protocols-plasma = { version = "0.2.0", features = [ "client" ], optional = true }
 x11-dl = { version = "2.18.5", optional = true }
 x11rb = { version = "0.13.0", default-features = false, features = ["allow-unsafe-code", "dl-libxcb", "randr", "resource_manager", "xinput", "xkb"], optional = true }
-xkbcommon-dl = "0.4.0"
+xkbcommon-dl = "0.4.2"
 
 [target.'cfg(target_os = "redox")'.dependencies]
 orbclient = { version = "0.3.42", default-features = false }

src/platform_impl/linux/common/mod.rs

@@ -1,2 +1 @@
-pub mod keymap;
-pub mod xkb_state;
+pub mod xkb;

src/platform_impl/linux/common/xkb/compose.rs

@@ -0,0 +1,124 @@
+//! XKB compose handling.
+
+use std::env;
+use std::ffi::CString;
+use std::ops::Deref;
+use std::os::unix::ffi::OsStringExt;
+use std::ptr::NonNull;
+
+use super::XkbContext;
+use super::XKBCH;
+use smol_str::SmolStr;
+use xkbcommon_dl::{
+    xkb_compose_compile_flags, xkb_compose_feed_result, xkb_compose_state, xkb_compose_state_flags,
+    xkb_compose_status, xkb_compose_table, xkb_keysym_t,
+};
+
+#[derive(Debug)]
+pub struct XkbComposeTable {
+    table: NonNull<xkb_compose_table>,
+}
+
+impl XkbComposeTable {
+    pub fn new(context: &XkbContext) -> Option<Self> {
+        let locale = env::var_os("LC_ALL")
+            .and_then(|v| if v.is_empty() { None } else { Some(v) })
+            .or_else(|| env::var_os("LC_CTYPE"))
+            .and_then(|v| if v.is_empty() { None } else { Some(v) })
+            .or_else(|| env::var_os("LANG"))
+            .and_then(|v| if v.is_empty() { None } else { Some(v) })
+            .unwrap_or_else(|| "C".into());
+        let locale = CString::new(locale.into_vec()).unwrap();
+
+        let table = unsafe {
+            (XKBCH.xkb_compose_table_new_from_locale)(
+                context.as_ptr(),
+                locale.as_ptr(),
+                xkb_compose_compile_flags::XKB_COMPOSE_COMPILE_NO_FLAGS,
+            )
+        };
+
+        let table = NonNull::new(table)?;
+        Some(Self { table })
+    }
+
+    /// Create new state with the given compose table.
+    pub fn new_state(&self) -> Option<XkbComposeState> {
+        let state = unsafe {
+            (XKBCH.xkb_compose_state_new)(
+                self.table.as_ptr(),
+                xkb_compose_state_flags::XKB_COMPOSE_STATE_NO_FLAGS,
+            )
+        };
+
+        let state = NonNull::new(state)?;
+        Some(XkbComposeState { state })
+    }
+}
+
+impl Deref for XkbComposeTable {
+    type Target = NonNull<xkb_compose_table>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.table
+    }
+}
+
+impl Drop for XkbComposeTable {
+    fn drop(&mut self) {
+        unsafe {
+            (XKBCH.xkb_compose_table_unref)(self.table.as_ptr());
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct XkbComposeState {
+    state: NonNull<xkb_compose_state>,
+}
+
+impl XkbComposeState {
+    pub fn get_string(&mut self, scratch_buffer: &mut Vec<u8>) -> Option<SmolStr> {
+        super::make_string_with(scratch_buffer, |ptr, len| unsafe {
+            (XKBCH.xkb_compose_state_get_utf8)(self.state.as_ptr(), ptr, len)
+        })
+    }
+
+    #[inline]
+    pub fn feed(&mut self, keysym: xkb_keysym_t) -> ComposeStatus {
+        let feed_result = unsafe { (XKBCH.xkb_compose_state_feed)(self.state.as_ptr(), keysym) };
+        match feed_result {
+            xkb_compose_feed_result::XKB_COMPOSE_FEED_IGNORED => ComposeStatus::Ignored,
+            xkb_compose_feed_result::XKB_COMPOSE_FEED_ACCEPTED => {
+                ComposeStatus::Accepted(self.status())
+            }
+        }
+    }
+
+    #[inline]
+    pub fn reset(&mut self) {
+        unsafe {
+            (XKBCH.xkb_compose_state_reset)(self.state.as_ptr());
+        }
+    }
+
+    #[inline]
+    pub fn status(&mut self) -> xkb_compose_status {
+        unsafe { (XKBCH.xkb_compose_state_get_status)(self.state.as_ptr()) }
+    }
+}
+
+impl Drop for XkbComposeState {
+    fn drop(&mut self) {
+        unsafe {
+            (XKBCH.xkb_compose_state_unref)(self.state.as_ptr());
+        };
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum ComposeStatus {
+    Accepted(xkb_compose_status),
+    Ignored,
+    None,
+}

src/platform_impl/linux/common/keymap.rs → src/platform_impl/linux/common/xkb/keymap.rs

@@ -1,6 +1,24 @@
-//! Convert XKB keys to Winit keys.
+//! XKB keymap.
+
+use std::ffi::c_char;
+use std::ops::Deref;
+use std::ptr::{self, NonNull};
+
+#[cfg(x11_platform)]
+use x11_dl::xlib_xcb::xcb_connection_t;
+#[cfg(wayland_platform)]
+use {memmap2::MmapOptions, std::os::unix::io::OwnedFd};
+
+use xkb::XKB_MOD_INVALID;
+use xkbcommon_dl::{
+    self as xkb, xkb_keycode_t, xkb_keymap, xkb_keymap_compile_flags, xkb_keysym_t,
+    xkb_layout_index_t, xkb_mod_index_t,
+};
 
 use crate::keyboard::{Key, KeyCode, KeyLocation, NamedKey, NativeKey, NativeKeyCode, PhysicalKey};
+#[cfg(x11_platform)]
+use crate::platform_impl::common::xkb::XKBXH;
+use crate::platform_impl::common::xkb::{XkbContext, XKBH};
 
 /// Map the raw X11-style keycode to the `KeyCode` enum.
 ///
@@ -894,3 +912,140 @@ pub fn keysym_location(keysym: u32) -> KeyLocation {
         _ => KeyLocation::Standard,
     }
 }
+
+#[derive(Debug)]
+pub struct XkbKeymap {
+    keymap: NonNull<xkb_keymap>,
+    _mods_indices: ModsIndices,
+    pub _core_keyboard_id: i32,
+}
+
+impl XkbKeymap {
+    #[cfg(wayland_platform)]
+    pub fn from_fd(context: &XkbContext, fd: OwnedFd, size: usize) -> Option<Self> {
+        let map = unsafe { MmapOptions::new().len(size).map_copy_read_only(&fd).ok()? };
+
+        let keymap = unsafe {
+            let keymap = (XKBH.xkb_keymap_new_from_string)(
+                (*context).as_ptr(),
+                map.as_ptr() as *const _,
+                xkb::xkb_keymap_format::XKB_KEYMAP_FORMAT_TEXT_V1,
+                xkb_keymap_compile_flags::XKB_KEYMAP_COMPILE_NO_FLAGS,
+            );
+            NonNull::new(keymap)?
+        };
+
+        Some(Self::new_inner(keymap, 0))
+    }
+
+    #[cfg(x11_platform)]
+    pub fn from_x11_keymap(
+        context: &XkbContext,
+        xcb: *mut xcb_connection_t,
+        core_keyboard_id: i32,
+    ) -> Option<Self> {
+        let keymap = unsafe {
+            (XKBXH.xkb_x11_keymap_new_from_device)(
+                context.as_ptr(),
+                xcb,
+                core_keyboard_id,
+                xkb_keymap_compile_flags::XKB_KEYMAP_COMPILE_NO_FLAGS,
+            )
+        };
+        let keymap = NonNull::new(keymap)?;
+        Some(Self::new_inner(keymap, core_keyboard_id))
+    }
+
+    fn new_inner(keymap: NonNull<xkb_keymap>, _core_keyboard_id: i32) -> Self {
+        let mods_indices = ModsIndices {
+            shift: mod_index_for_name(keymap, xkb::XKB_MOD_NAME_SHIFT),
+            caps: mod_index_for_name(keymap, xkb::XKB_MOD_NAME_CAPS),
+            ctrl: mod_index_for_name(keymap, xkb::XKB_MOD_NAME_CTRL),
+            alt: mod_index_for_name(keymap, xkb::XKB_MOD_NAME_ALT),
+            num: mod_index_for_name(keymap, xkb::XKB_MOD_NAME_NUM),
+            mod3: mod_index_for_name(keymap, b"Mod3\0"),
+            logo: mod_index_for_name(keymap, xkb::XKB_MOD_NAME_LOGO),
+            mod5: mod_index_for_name(keymap, b"Mod5\0"),
+        };
+
+        Self {
+            keymap,
+            _mods_indices: mods_indices,
+            _core_keyboard_id,
+        }
+    }
+
+    #[cfg(x11_platform)]
+    pub fn mods_indices(&self) -> ModsIndices {
+        self._mods_indices
+    }
+
+    pub fn first_keysym_by_level(
+        &mut self,
+        layout: xkb_layout_index_t,
+        keycode: xkb_keycode_t,
+    ) -> xkb_keysym_t {
+        unsafe {
+            let mut keysyms = ptr::null();
+            let count = (XKBH.xkb_keymap_key_get_syms_by_level)(
+                self.keymap.as_ptr(),
+                keycode,
+                layout,
+                // NOTE: The level should be zero to ignore modifiers.
+                0,
+                &mut keysyms,
+            );
+
+            if count == 1 {
+                *keysyms
+            } else {
+                0
+            }
+        }
+    }
+
+    /// Check whether the given key repeats.
+    pub fn key_repeats(&mut self, keycode: xkb_keycode_t) -> bool {
+        unsafe { (XKBH.xkb_keymap_key_repeats)(self.keymap.as_ptr(), keycode) == 1 }
+    }
+}
+
+impl Drop for XkbKeymap {
+    fn drop(&mut self) {
+        unsafe {
+            (XKBH.xkb_keymap_unref)(self.keymap.as_ptr());
+        };
+    }
+}
+
+impl Deref for XkbKeymap {
+    type Target = NonNull<xkb_keymap>;
+    fn deref(&self) -> &Self::Target {
+        &self.keymap
+    }
+}
+
+/// Modifier index in the keymap.
+#[derive(Default, Debug, Clone, Copy)]
+pub struct ModsIndices {
+    pub shift: Option<xkb_mod_index_t>,
+    pub caps: Option<xkb_mod_index_t>,
+    pub ctrl: Option<xkb_mod_index_t>,
+    pub alt: Option<xkb_mod_index_t>,
+    pub num: Option<xkb_mod_index_t>,
+    pub mod3: Option<xkb_mod_index_t>,
+    pub logo: Option<xkb_mod_index_t>,
+    pub mod5: Option<xkb_mod_index_t>,
+}
+
+fn mod_index_for_name(keymap: NonNull<xkb_keymap>, name: &[u8]) -> Option<xkb_mod_index_t> {
+    unsafe {
+        let mod_index =
+            (XKBH.xkb_keymap_mod_get_index)(keymap.as_ptr(), name.as_ptr() as *const c_char);
+        if mod_index == XKB_MOD_INVALID {
+            None
+        } else {
+            Some(mod_index)
+        }
+    }
+}