Support IMM32 reconversion on Windows

views/ime/input_method_win.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "views/ime/input_method_win.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "ui/base/keycodes/keyboard_codes.h"
@@ skipping 97 matching lines @@
       break;
     case WM_IME_STARTCOMPOSITION:
       result = OnImeStartComposition(message, w_param, l_param, handled);
       break;
     case WM_IME_COMPOSITION:
       result = OnImeComposition(message, w_param, l_param, handled);
       break;
     case WM_IME_ENDCOMPOSITION:
       result = OnImeEndComposition(message, w_param, l_param, handled);
       break;
+    case WM_IME_REQUEST:
+      result = OnImeRequest(message, w_param, l_param, handled);
+      break;
     case WM_CHAR:
     case WM_SYSCHAR:
       result = OnChar(message, w_param, l_param, handled);
       break;
     case WM_DEADCHAR:
     case WM_SYSDEADCHAR:
       result = OnDeadChar(message, w_param, l_param, handled);
       break;
     default:
       NOTREACHED() << "Unknown IME message:" << message;
@@ skipping 84 matching lines @@
     return 0;
 
   if (GetTextInputClient()->HasCompositionText())
     GetTextInputClient()->ClearCompositionText();
 
   ime_input_.ResetComposition(hwnd());
   ime_input_.DestroyImeWindow(hwnd());
   return 0;
 }
 
+LRESULT InputMethodWin::OnImeRequest(
+    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
+  *handled = FALSE;
+
+  // Should not receive WM_IME_REQUEST message, if IME is disabled.
+  const ui::TextInputType type = GetTextInputType();
+  if (type == ui::TEXT_INPUT_TYPE_NONE ||
+      type == ui::TEXT_INPUT_TYPE_PASSWORD) {
+    return 0;
+  }
+
+  switch (wparam) {
+    case IMR_RECONVERTSTRING:
+      *handled = TRUE;
+      return OnReconvertString(reinterpret_cast<RECONVERTSTRING*>(lparam));
+    case IMR_DOCUMENTFEED:
+      *handled = TRUE;
+      return OnDocumentFeed(reinterpret_cast<RECONVERTSTRING*>(lparam));
+    default:
+      return 0;
+  }
+}
+
 LRESULT InputMethodWin::OnChar(
     UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
   *handled = TRUE;
 
   // We need to send character events to the focused text input client event if
   // its text input type is ui::TEXT_INPUT_TYPE_NONE.
   if (!GetTextInputClient())
     return 0;
 
   int flags = 0;
@@ skipping 15 matching lines @@
   // what dead key was pressed.
   ui::CompositionText composition;
   composition.text.assign(1, static_cast<char16>(wparam));
   composition.selection = ui::Range(0, 1);
   composition.underlines.push_back(
       ui::CompositionUnderline(0, 1, SK_ColorBLACK, false));
   GetTextInputClient()->SetCompositionText(composition);
   return 0;
 }
 
+LRESULT InputMethodWin::OnDocumentFeed(RECONVERTSTRING *reconv) {
+  TextInputClient* client = GetTextInputClient();
+  if (!client)
+    return 0;
+
+  ui::Range text_range;
+  if (!client->GetTextRange(&text_range) || text_range.is_empty())
+    return 0;
+
+  bool result = false;
+  ui::Range target_range;
+  if (client->HasCompositionText())
+    result = client->GetCompositionTextRange(&target_range);
+
+  if (!result || target_range.is_empty()) {
+    if (!client->GetSelectionRange(&target_range) ||
+        !target_range.IsValid()) {
+      return 0;
+    }
+  }
+
+  if (!text_range.Contains(target_range))
+    return 0;
+
+  size_t len = text_range.length();
+  size_t need_size = sizeof(RECONVERTSTRING) + len * sizeof(WCHAR);
+
+  if (!reconv)
+    return need_size;
+
+  if (reconv->dwSize < need_size)
+    return 0;
+
+  string16 text;
+  if (!GetTextInputClient()->GetTextFromRange(text_range, &text))
+    return 0;
+
+  reconv->dwVersion = 0;
+  reconv->dwStrLen = len;
+  reconv->dwStrOffset = sizeof(RECONVERTSTRING);
+  reconv->dwCompStrLen =
+      client->HasCompositionText() ? target_range.length() : 0;
+  reconv->dwCompStrOffset =
+      (target_range.GetMin() - text_range.start()) * sizeof(WCHAR);
+  reconv->dwTargetStrLen = target_range.length();
+  reconv->dwTargetStrOffset = reconv->dwCompStrOffset;
+
+  memcpy((char*)reconv + sizeof(RECONVERTSTRING),
+      text.c_str(), len * sizeof(WCHAR));
+
+  return reinterpret_cast<LRESULT>(reconv);
+}
+
+LRESULT InputMethodWin::OnReconvertString(RECONVERTSTRING *reconv) {
+  TextInputClient* client = GetTextInputClient();
+  if (!client)
+    return 0;
+
+  // If there is a composition string already, we don't allow reconversion.
+  if (client->HasCompositionText())
+    return 0;
+
+  ui::Range text_range;
+  if (!client->GetTextRange(&text_range) || text_range.is_empty())
+    return 0;
+
+  ui::Range selection_range;
+  if (!client->GetSelectionRange(&selection_range) ||
+      selection_range.is_empty()) {
+    return 0;
+  }
+
+  DCHECK(text_range.Contains(selection_range));
+
+  size_t len = selection_range.length();
+  size_t need_size = sizeof(RECONVERTSTRING) + len * sizeof(WCHAR);

[Peng, 2011/10/27 00:28:00]

I checked document of IMR_RECONVERTSTRING & IMR_DOCUMENTFEED. It is just for IME
requiring a piece of text which application want to reconvert. If IME want to
make it more accurate, the IME could use IMR_DOCUMENTFEED for more content.

[James Su, 2011/10/27 04:56:39]

When doing reconversion, the IME can use the surrounding context provided by
IMR_RECONVERTSTRING to improve the accuracy.
IMR_DOCUMENTFEED is used when the IME wants to improve the accuracy of normal
input, e.g. inserting new text in the middle of existing document.

[Peng, 2011/10/27 16:12:24]

Because we do not implement the logic to allow IME adjust the reconvert range.
And providing extra text to IME can also cause information leaking. So I decide
to just return the text in the selection range right now until we can support
adjusting the reconvert range and figure out the privacy impact.

I am also wondering if I should remove OnDocumentFeed(). I tested with some
IMEs, did not find any IME use this message. But this function may have security
issue.

[James Su, 2011/10/27 18:39:49]

You still don't get the point.
1) This method has nothing to do with the "set reconvert range" thing. They are
independent functionalities.
2) Returning some extra surrounding context along with the selection text can
improve the reconversion accuracy if the input method can make use the
information.
3) I don't think the privacy impact is a big issue, as we already return the
text inside the selection range. Returning a little more text won't make the
situation worse.
It may not be very easy to find out whether an IME uses this feature or not.
Because the IME method will still work without this feature. it'll only affect
the conversion accuracy.
I think this method is nice to have. And the privacy issue should not be a big
deal. As we already support similar feature on Mac.

+
+  if (!reconv)
+    return need_size;
+
+  if (reconv->dwSize < need_size)
+    return 0;
+
+  string16 text;
+  if (!GetTextInputClient()->GetTextFromRange(selection_range, &text))
+    return 0;
+
+  reconv->dwVersion = 0;
+  reconv->dwStrLen = len;
+  reconv->dwStrOffset = sizeof(RECONVERTSTRING);
+  reconv->dwCompStrLen = len;
+  reconv->dwCompStrOffset = 0;
+  reconv->dwTargetStrLen = len;
+  reconv->dwTargetStrOffset = 0;
+
+  memcpy(reinterpret_cast<char*>(reconv) + sizeof(RECONVERTSTRING),
+      text.c_str(), len * sizeof(WCHAR));
+
+  return reinterpret_cast<LRESULT>(reconv);
+}
+
 void InputMethodWin::ConfirmCompositionText() {
   if (!IsTextInputTypeNone()) {
     ime_input_.CleanupComposition(hwnd());
     // Though above line should confirm the client's composition text by sending
     // a result text to us, in case the input method and the client are in
     // inconsistent states, we check the client's composition state again.
     if (GetTextInputClient()->HasCompositionText())
       GetTextInputClient()->ConfirmCompositionText();
   }
 }
 
 void InputMethodWin::UpdateIMEState() {
   // Use switch here in case we are going to add more text input types.
   // We disable input method in password field.
   switch (GetTextInputType()) {
     case ui::TEXT_INPUT_TYPE_NONE:
     case ui::TEXT_INPUT_TYPE_PASSWORD:
       ime_input_.DisableIME(hwnd());
       break;
     default:
       ime_input_.EnableIME(hwnd());
       break;
   }
 }
 
 }  // namespace views