fix(tip): override IMM32 property to enable commit on unselect

Author: kanru

editor/src-tauri/Cargo.lock

@@ -0,0 +1,42 @@
+//! Undocumented IMM32 API.
+
+pub(crate) const IME_PROP_COMPLETE_ON_UNSELECT: u32 = 0x00100000;
+
+use windows::Win32::{Foundation::HINSTANCE, UI::Input::KeyboardAndMouse::HKL};
+
+// Retrieve the pointer to an IME instance
+//
+// See https://github.com/reactos/reactos/blob/80bd4608363683131411f131e8783749e51835c5/win32ss/user/imm32/ime.c#L531
+windows_core::link!("imm32.dll" "system" fn ImmLockImeDpi(hkl: HKL) -> *mut ImeDpi);
+
+// Return the pointer of an IME instance
+//
+// See https://github.com/reactos/reactos/blob/80bd4608363683131411f131e8783749e51835c5/win32ss/user/imm32/ime.c#L561
+windows_core::link!("imm32.dll" "system" fn ImmUnlockImeDpi(pimedpi: *mut ImeDpi));
+
+// IME info
+//
+// See https://github.com/reactos/reactos/blob/80bd4608363683131411f131e8783749e51835c5/sdk/include/ddk/immdev.h#L20
+#[repr(C)]
+pub(crate) struct ImeInfo {
+    pub(crate) dw_private_data_size: u32,
+    pub(crate) fdw_property: u32,
+    pub(crate) fdw_conversion_caps: u32,
+    pub(crate) fdw_sentence_caps: u32,
+    pub(crate) fdw_uicaps: u32,
+    pub(crate) fdw_scscaps: u32,
+    pub(crate) fdw_select_caps: u32,
+}
+
+// IME instance struct
+//
+// Unused remaining fields are not included.
+//
+// See https://github.com/reactos/reactos/blob/80bd4608363683131411f131e8783749e51835c5/sdk/include/reactos/imm32_undoc.h#L91
+#[repr(C)]
+pub(crate) struct ImeDpi {
+    pnext: *const ImeDpi,
+    hinst: HINSTANCE,
+    hkl: HKL,
+    pub(crate) ime_info: ImeInfo,
+}

preferences/src-tauri/Cargo.lock

@@ -2,6 +2,7 @@
 
 mod com;
 pub mod config;
+mod imm32;
 mod keybind;
 mod logging;
 mod text_service;

tip/src/imm32.rs

@@ -776,16 +776,30 @@ impl ChewingTextService {
         ecwrite: u32,
         composition: &ITfComposition,
     ) -> Result<()> {
-        // commit current preedit
         unsafe {
+            let composition_range = composition
+                .GetRange()
+                .inspect_err(|_| debug!("failed to get composition range"))?;
             let doc_mgr = self
                 .thread_mgr
                 .GetFocus()
                 .context("failed to get current ITfDocumentMgr")?;
             let context = doc_mgr
                 .GetTop()
                 .context("failed to get current ITfContext")?;
-            EndComposition::will_end_composition(&context, composition, ecwrite)?;
+
+            // When a composition is interrupted by the application we only need to
+            // clear the display attributes. When I tested this, clearing the display attribute
+            // is not necessary, but this is what mozc was doing.
+            //
+            // In pure TSF mode, the composition string is automatically committed on termination.
+            // In TSF/IMM32 bridge mode, the bridge sets a default property which we override to
+            // have the same commit on unselect behavior. See [`TextService_Impl::Activate`].
+            let disp_attr_prop =
+                context.GetProperty(&windows::Win32::UI::TextServices::GUID_PROP_ATTRIBUTE)?;
+            disp_attr_prop
+                .Clear(ecwrite, &composition_range)
+                .inspect_err(|_| debug!("failed to clear display attribute"))?;
         }
         self.on_composition_terminated_tail()
     }

tip/src/lib.rs

@@ -171,18 +171,18 @@ impl EndComposition {
         ec: u32,
     ) -> Result<()> {
         unsafe {
-            let range = composition
+            let composition_range = composition
                 .GetRange()
                 .inspect_err(|_| debug!("failed to get composition range"))?;
             let disp_attr_prop = context.GetProperty(&GUID_PROP_ATTRIBUTE)?;
             disp_attr_prop
-                .Clear(ec, &range)
+                .Clear(ec, &composition_range)
                 .inspect_err(|_| debug!("failed to clear display attribute"))?;
 
-            let new_composition_start = range.Clone()?;
-            new_composition_start.Collapse(ec, TF_ANCHOR_END)?;
-            composition.ShiftStart(ec, &new_composition_start)?;
-            set_selection(context, ec, new_composition_start, TF_AE_END)?;
+            composition_range.Collapse(ec, TF_ANCHOR_END)?;
+            composition.ShiftStart(ec, &composition_range)?;
+            composition.ShiftEnd(ec, &composition_range)?;
+            set_selection(context, ec, composition_range, TF_AE_END)?;
         }
         Ok(())
     }

tip/src/text_service/chewing.rs

@@ -1,18 +1,24 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-use std::cell::{Cell, RefCell};
+use std::{
+    cell::{Cell, RefCell},
+    ptr::null_mut,
+};
 
 use log::{debug, error};
 use windows::Win32::{
     Foundation::{E_UNEXPECTED, FALSE, LPARAM, WPARAM},
-    UI::TextServices::*,
+    UI::{Input::KeyboardAndMouse::GetKeyboardLayout, TextServices::*},
 };
 use windows_core::{
     BOOL, BSTR, ComObjectInterface, GUID, IUnknown, IUnknown_Vtbl, Interface, InterfaceRef, Ref,
     Result, implement, interface,
 };
 
-use crate::text_service::chewing::ReentrantOps;
+use crate::{
+    imm32::{IME_PROP_COMPLETE_ON_UNSELECT, ImeDpi, ImmLockImeDpi, ImmUnlockImeDpi},
+    text_service::chewing::ReentrantOps,
+};
 
 use self::chewing::ChewingTextService;
 use self::display_attribute::{EnumTfDisplayAttributeInfo, get_display_attribute_info};
@@ -62,6 +68,7 @@ pub(super) struct TextService {
     keyboard_openclose_cookie: Cell<u32>,
     key_busy: Cell<bool>,
     composition_terminated: Cell<bool>,
+    pimedpi: Cell<*mut ImeDpi>,
 }
 
 impl TextService {
@@ -73,6 +80,7 @@ impl TextService {
             keyboard_openclose_cookie: Cell::new(TF_INVALID_COOKIE),
             key_busy: Cell::new(false),
             composition_terminated: Cell::new(false),
+            pimedpi: Cell::new(null_mut()),
         }
     }
     fn tail_handler(&self) {
@@ -143,6 +151,18 @@ impl IFnRunCommand_Impl for TextService_Impl {
 impl ITfTextInputProcessor_Impl for TextService_Impl {
     fn Activate(&self, ptim: Ref<ITfThreadMgr>, tid: u32) -> Result<()> {
         debug!(tid; "tip::activate");
+
+        debug!("trying to override the default IMM32 property set by MSCTF.dll");
+        let hkl = unsafe { GetKeyboardLayout(0) };
+        let pimedpi = unsafe { ImmLockImeDpi(hkl) };
+        if let Some(imedpi) = unsafe { pimedpi.as_mut() } {
+            imedpi.ime_info.fdw_property |= IME_PROP_COMPLETE_ON_UNSELECT;
+            debug!("done adding IME_PROP_COMPLETE_ON_UNSELECT to IME property");
+        } else {
+            debug!("unable to get the PIMEDPI pointer");
+        }
+        self.pimedpi.set(pimedpi);
+
         self.tid.set(tid);
         let mut ts = self.inner.borrow_mut();
         let mut thread_cookies = self.thread_cookies.borrow_mut();
@@ -186,6 +206,11 @@ impl ITfTextInputProcessor_Impl for TextService_Impl {
 
     fn Deactivate(&self) -> Result<()> {
         debug!("tip::deactivate");
+        if !self.pimedpi.get().is_null() {
+            debug!("releasing previously acquired PIMEDPI pointer");
+            unsafe { ImmUnlockImeDpi(self.pimedpi.get()) };
+            self.pimedpi.set(null_mut());
+        }
         let thread_cookies = self.thread_cookies.take();
 
         if let Some(ts) = self.inner.borrow_mut().take() {