Support IMM32 reconversion on Windows

views/ime/input_method_win.cc

Index: views/ime/input_method_win.cc
diff --git a/views/ime/input_method_win.cc b/views/ime/input_method_win.cc
index 4ab1a187378d389ba70bf8dc6d3131b107afa847..38278daa2d23489a14b91169c4566bcd683340e6 100644
--- a/views/ime/input_method_win.cc
+++ b/views/ime/input_method_win.cc
@@ -4,6 +4,8 @@
 
 #include "views/ime/input_method_win.h"
 
+#include <algorithm>
+
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/string_util.h"
@@ -115,6 +117,9 @@ LRESULT InputMethodWin::OnImeMessages(
     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);
@@ -219,6 +224,126 @@ LRESULT InputMethodWin::OnImeEndComposition(
   return 0;
 }
 
+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 selection_range;
+  if (!client->GetSelectionRange(&selection_range) ||
+      selection_range.is_empty()) {
+    return 0;
+  }
+
+  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;
+
+  string16 text;
+  ui::Range actual_range;
+  if (!GetTextInputClient()->GetTextFromRange(
+      selection_range, &text, &actual_range))
+    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 need_size;
+}
+
+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;
+
+  ui::Range target_range;
+  do {
+    if (client->HasCompositionText() &&
+        client->GetCompositionTextRange(&target_range) &&
+        !target_range.is_empty()) {
+      break;
+    }
+    if (client->GetSelectionRange(&target_range))
+      break;
+    return 0;
+  } while (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;
+  ui::Range actual_range;
+  if (!GetTextInputClient()->GetTextFromRange(
+      text_range, &text, &actual_range)) {
+    return 0;
+  }
+
+  DCHECK(text_range == actual_range);
+
+  reconv->dwVersion = 0;
+  reconv->dwStrLen = len;
+  reconv->dwStrOffset = sizeof(RECONVERTSTRING);
+  reconv->dwCompStrLen =
+      client->HasCompositionText() ? reconv->dwTargetStrOffset : 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 need_size;
+}
+
+LRESULT InputMethodWin::OnImeRequest(
+    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
+  *handled = FALSE;
+
+  if (IsTextInputTypeNone())
+    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;