[FYI] All-in-one OnCandidateWindow{Show,Update,Hide}

ui/base/ime/win/tsf_bridge.cc

 // Copyright (c) 2012 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 <msctf.h>
 
 #include <map>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/thread_local_storage.h"
 #include "base/win/scoped_comptr.h"
 #include "base/win/scoped_variant.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/base/ime/win/tsf_bridge.h"
 #include "ui/base/ime/win/tsf_text_store.h"
 
 namespace ui {
 
 namespace {
 
 // We use thread local storage for TSFBridge lifespan management.
 base::ThreadLocalStorage::StaticSlot tls_tsf_bridge = TLS_INITIALIZER;
 
 
 // TsfBridgeDelegate -----------------------------------------------------------
 
 // A TLS implementation of TSFBridge.
-class TSFBridgeDelegate : public TSFBridge {
+class TSFBridgeDelegate : public TSFBridge,
+                          public base::SupportsWeakPtr<TSFBridgeDelegate> {
  public:
   TSFBridgeDelegate();
   virtual ~TSFBridgeDelegate();
 
   bool Initialize();
 
   // TsfBridge:
   virtual void OnTextInputTypeChanged(const TextInputClient* client) OVERRIDE;
   virtual void OnTextLayoutChanged() OVERRIDE;
   virtual bool CancelComposition() OVERRIDE;
   virtual bool ConfirmComposition() OVERRIDE;
   virtual void SetFocusedClient(HWND focused_window,
                                 TextInputClient* client) OVERRIDE;
   virtual void RemoveFocusedClient(TextInputClient* client) OVERRIDE;
   virtual base::win::ScopedComPtr<ITfThreadMgr> GetThreadManager() OVERRIDE;
   virtual TextInputClient* GetFocusedTextInputClient() const OVERRIDE;
 
+  // See also *Callback functions below. To avoid reentrancy issue that
+  // TextInputClient manipulates IME state during even handling, these methods
+  // defer sending actual signals to renderer.
+  virtual void OnCandidateWindowShown() OVERRIDE;
+  virtual void OnCandidateWindowUpdated() OVERRIDE;
+  virtual void OnCandidateWindowHidden() OVERRIDE;
+
  private:
   // Returns true if |tsf_document_map_| is successfully initialized. This
   // method should be called from and only from Initialize().
   bool InitializeDocumentMapInternal();
 
   // Returns true if |context| is successfully updated to be a disabled
   // context, where an IME should be deactivated. This is suitable for some
   // special input context such as password fields.
   bool InitializeDisabledContext(ITfContext* context);
 
@@ skipping 24 matching lines @@
   //   TSFBridge::SetFocusedClient is called first then the target window
   //   receives WM_ACTIVATE. This actually occurs in Aura environment where
   //   WM_NCACTIVATE is used as a trigger to restore text input focus.
   // Caveats:
   //   TSF runtime does not increment the reference count of the attached
   //   document manager. See the comment inside the method body for
   //   details.
   void UpdateAssociateFocus();
   void ClearAssociateFocus();
 
+  // Deferred callbacks for signalling TextInputClient about candidate window
+  // appearance changes.
+  void CandidateWindowShownCallback();
+  void CandidateWindowUpdatedCallback();
+  void CandidateWindowHiddenCallback();
+
   // A triple of document manager, text store and binding cookie between
   // a context owned by the document manager and the text store. This is a
   // minimum working set of an editable document in TSF.
   struct TSFDocument {
    public:
     TSFDocument() : cookie(TF_INVALID_COOKIE) {}
     TSFDocument(const TSFDocument& src)
         : document_manager(src.document_manager),
           cookie(src.cookie) {}
     base::win::ScopedComPtr<ITfDocumentMgr> document_manager;
@@ skipping 374 matching lines @@
   if (it == tsf_document_map_.end()) {
     it = tsf_document_map_.find(TEXT_INPUT_TYPE_TEXT);
     // This check is necessary because it's possible that we failed to
     // initialize |tsf_document_map_| and it has no TEXT_INPUT_TYPE_TEXT.
     if (it == tsf_document_map_.end())
       return NULL;
   }
   return &it->second;
 }
 
+void TSFBridgeDelegate::OnCandidateWindowShown() {
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&TSFBridgeDelegate::CandidateWindowShownCallback,
+                 AsWeakPtr()));
+}
+
+void TSFBridgeDelegate::OnCandidateWindowUpdated() {
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&TSFBridgeDelegate::CandidateWindowUpdatedCallback,
+                 AsWeakPtr()));
+}
+
+void TSFBridgeDelegate::OnCandidateWindowHidden() {
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&TSFBridgeDelegate::CandidateWindowHiddenCallback,
+                 AsWeakPtr()));
+}
+
+void TSFBridgeDelegate::CandidateWindowShownCallback() {
+  TextInputClient* client = GetFocusedTextInputClient();
+  if (client)
+      client->OnCandidateWindowShown();
+}
+
+void TSFBridgeDelegate::CandidateWindowUpdatedCallback() {
+  TextInputClient* client = GetFocusedTextInputClient();
+  if (client)
+      client->OnCandidateWindowUpdated();
+}
+
+void TSFBridgeDelegate::CandidateWindowHiddenCallback() {
+  TextInputClient* client = GetFocusedTextInputClient();
+  if (client)
+      client->OnCandidateWindowHidden();
+}
+
 }  // namespace
 
 
 // TsfBridge  -----------------------------------------------------------------
 
 TSFBridge::TSFBridge() {
 }
 
 TSFBridge::~TSFBridge() {
 }
@@ skipping 52 matching lines @@
   return delegate;
 }
 
 // static
 void TSFBridge::Finalize(void* data) {
   TSFBridgeDelegate* delegate = static_cast<TSFBridgeDelegate*>(data);
   delete delegate;
 }
 
 }  // namespace ui