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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef UI_BASE_IME_INPUT_METHOD_BASE_H_
      6 #define UI_BASE_IME_INPUT_METHOD_BASE_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/compiler_specific.h"
     10 #include "base/memory/weak_ptr.h"
     11 #include "base/observer_list.h"
     12 #include "ui/base/ime/input_method.h"
     13 #include "ui/base/ui_base_export.h"
     14 
     15 namespace gfx {
     16 class Rect;
     17 }  // namespace gfx
     18 
     19 namespace ui {
     20 
     21 class InputMethodObserver;
     22 class KeyEvent;
     23 class TextInputClient;
     24 
     25 // A helper class providing functionalities shared among ui::InputMethod
     26 // implementations.
     27 class UI_BASE_EXPORT InputMethodBase
     28    : NON_EXPORTED_BASE(public InputMethod),
     29      public base::SupportsWeakPtr<InputMethodBase> {
     30  public:
     31   InputMethodBase();
     32   virtual ~InputMethodBase();
     33 
     34   // Overriden from InputMethod.
     35   virtual void SetDelegate(internal::InputMethodDelegate* delegate) OVERRIDE;
     36   virtual void Init(bool focused) OVERRIDE;
     37   // If a derived class overrides OnFocus()/OnBlur(), it should call parent's
     38   // implementation first, to make sure |system_toplevel_window_focused_| flag
     39   // can be updated correctly.
     40   virtual void OnFocus() OVERRIDE;
     41   virtual void OnBlur() OVERRIDE;
     42   virtual void SetFocusedTextInputClient(TextInputClient* client) OVERRIDE;
     43   virtual void DetachTextInputClient(TextInputClient* client) OVERRIDE;
     44   virtual TextInputClient* GetTextInputClient() const OVERRIDE;
     45 
     46   // If a derived class overrides this method, it should call parent's
     47   // implementation.
     48   virtual void OnTextInputTypeChanged(const TextInputClient* client) OVERRIDE;
     49 
     50   virtual TextInputType GetTextInputType() const OVERRIDE;
     51   virtual TextInputMode GetTextInputMode() const OVERRIDE;
     52   virtual bool CanComposeInline() const OVERRIDE;
     53   virtual void ShowImeIfNeeded() OVERRIDE;
     54 
     55   virtual void AddObserver(InputMethodObserver* observer) OVERRIDE;
     56   virtual void RemoveObserver(InputMethodObserver* observer) OVERRIDE;
     57 
     58  protected:
     59   virtual void OnWillChangeFocusedClient(TextInputClient* focused_before,
     60                                          TextInputClient* focused) {}
     61   virtual void OnDidChangeFocusedClient(TextInputClient* focused_before,
     62                                         TextInputClient* focused) {}
     63 
     64   // Returns true if |client| is currently focused.
     65   bool IsTextInputClientFocused(const TextInputClient* client);
     66 
     67   // Checks if the focused text input client's text input type is
     68   // TEXT_INPUT_TYPE_NONE. Also returns true if there is no focused text
     69   // input client.
     70   bool IsTextInputTypeNone() const;
     71 
     72   // Convenience method to call the focused text input client's
     73   // OnInputMethodChanged() method. It'll only take effect if the current text
     74   // input type is not TEXT_INPUT_TYPE_NONE.
     75   void OnInputMethodChanged() const;
     76 
     77   // Convenience method to call delegate_->DispatchKeyEventPostIME().
     78   // Returns true if the event was processed
     79   bool DispatchKeyEventPostIME(const ui::KeyEvent& event) const;
     80 
     81   // Convenience method to notify all observers of TextInputClient changes.
     82   void NotifyTextInputStateChanged(const TextInputClient* client);
     83 
     84   // Interface for for signalling candidate window events.
     85   // See also *Callback functions below. To avoid reentrancy issue that
     86   // TextInputClient manipulates IME state during even handling, these methods
     87   // defer sending actual signals to renderer.
     88   void OnCandidateWindowShown();
     89   void OnCandidateWindowUpdated();
     90   void OnCandidateWindowHidden();
     91 
     92   bool system_toplevel_window_focused() const {
     93     return system_toplevel_window_focused_;
     94   }
     95 
     96  private:
     97   void SetFocusedTextInputClientInternal(TextInputClient* client);
     98 
     99   // Deferred callbacks for signalling TextInputClient about candidate window
    100   // appearance changes.
    101   void CandidateWindowShownCallback();
    102   void CandidateWindowUpdatedCallback();
    103   void CandidateWindowHiddenCallback();
    104 
    105   internal::InputMethodDelegate* delegate_;
    106   TextInputClient* text_input_client_;
    107 
    108   ObserverList<InputMethodObserver> observer_list_;
    109 
    110   bool system_toplevel_window_focused_;
    111 
    112   DISALLOW_COPY_AND_ASSIGN(InputMethodBase);
    113 };
    114 
    115 }  // namespace ui
    116 
    117 #endif  // UI_BASE_IME_INPUT_METHOD_BASE_H_
    118