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"
 #include "views/events/event.h"
 
+// Extra number of chars before and after selection (or composition) range which
+// is returned to IME for improving conversion accuracy.
+static const size_t kExtraNumberOfChars = 20;
+
 namespace views {
 
 InputMethodWin::InputMethodWin(internal::InputMethodDelegate* delegate)
     : active_(false),
       direction_(base::i18n::UNKNOWN_DIRECTION),
       pending_requested_direction_(base::i18n::UNKNOWN_DIRECTION) {
   set_delegate(delegate);
 }
 
 InputMethodWin::~InputMethodWin() {
@@ skipping 85 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;
+
+  if (target_range.GetMin() - text_range.start() > kExtraNumberOfChars)
+    text_range.set_start(target_range.GetMin() - kExtraNumberOfChars);
+
+  if (text_range.end() - target_range.GetMax() > kExtraNumberOfChars)
+    text_range.set_end(target_range.GetMax() + kExtraNumberOfChars);
+
+  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;

[James Su, 2011/10/28 18:16:04]

nit: DCHECK_EQ(text_range.length(), text.length());

[Peng, 2011/10/28 19:13:06]

Done.

+
+  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));

[James Su, 2011/10/28 18:16:04]

nit: alignment.

[Peng, 2011/10/28 19:13:06]

Done.

+
+  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);
+
+  if (!reconv)
+    return need_size;
+
+  if (reconv->dwSize < need_size)
+    return 0;
+
+  // Because we don't not support IME adjusts the reconvert range right now and
+  // returning extra content may have privacy issue. So in the first step, we
+  // don't return exrat content.

[James Su, 2011/10/28 18:16:04]

I'd suggest to remove this paragraph. As I said returning extra context has
nothing to do with adjusting the reconvert range. And I don't think there is a
privacy issue.

[Peng, 2011/10/28 19:13:06]

Done.

+  // TODO(penghuang): support IME adjusts the reconvert range.

[James Su, 2011/10/28 18:16:04]

Just: // TODO(penghuang): Return some extra context to help improve IME's
reconversion accuracy.

It's better to put the TODO of adjusting the reconvert range elsewhere. This
place has nothing to do with this feature.

[Peng, 2011/10/28 19:13:06]

Done.

+  string16 text;
+  if (!GetTextInputClient()->GetTextFromRange(selection_range, &text))
+    return 0;

[James Su, 2011/10/28 18:16:04]

nit: DCHECK_EQ(selection_range.length(), text.length());

[Peng, 2011/10/28 19:13:06]

Done.

+
+  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));

[James Su, 2011/10/28 18:16:04]

nit: alignment.

[Peng, 2011/10/28 19:13:06]

Done.

+
+  return reinterpret_cast<LRESULT>(reconv);

[James Su, 2011/10/28 18:16:04]

If you insistent on returning the pointer here, I'd suggest to add a comment in
case somebody else wants to change it back to size in the future.

[Peng, 2011/10/28 19:13:06]

Done.

+}
+
 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