chrome/browser/ui/views/status_icons/status_tray_state_changer_win.h

   1 // Copyright 2014 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 CHROME_BROWSER_UI_VIEWS_STATUS_ICONS_STATUS_TRAY_STATE_CHANGER_WIN_H_
   6 #define CHROME_BROWSER_UI_VIEWS_STATUS_ICONS_STATUS_TRAY_STATE_CHANGER_WIN_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/strings/string16.h"
  10 #include "base/threading/non_thread_safe.h"
  11 #include "base/win/iunknown_impl.h"
  12 #include "base/win/scoped_comptr.h"
  13
  14 // The known values for NOTIFYITEM's dwPreference member.
  15 enum NOTIFYITEM_PREFERENCE {
  16   // In Windows UI: "Only show notifications."
  17   PREFERENCE_SHOW_WHEN_ACTIVE = 0,
  18   // In Windows UI: "Hide icon and notifications."
  19   PREFERENCE_SHOW_NEVER = 1,
  20   // In Windows UI: "Show icon and notifications."
  21   PREFERENCE_SHOW_ALWAYS = 2
  22 };
  23
  24 // NOTIFYITEM describes an entry in Explorer's registry of status icons.
  25 // Explorer keeps entries around for a process even after it exits.
  26 struct NOTIFYITEM {
  27   PWSTR exe_name;    // The file name of the creating executable.
  28   PWSTR tip;         // The last hover-text value associated with this status
  29                      // item.
  30   HICON icon;        // The icon associated with this status item.
  31   HWND hwnd;         // The HWND associated with the status item.
  32   DWORD preference;  // Determines the behavior of the icon with respect to
  33                      // the taskbar. Values taken from NOTIFYITEM_PREFERENCE.
  34   UINT id;           // The ID specified by the application.  (hWnd, uID) is
  35                      // unique.
  36   GUID guid;         // The GUID specified by the application, alternative to
  37                      // uID.
  38 };
  39
  40 // INotificationCB is an interface that applications can implement in order to
  41 // receive notifications about the state of the notification area manager.
  42 class __declspec(uuid("D782CCBA-AFB0-43F1-94DB-FDA3779EACCB")) INotificationCB
  43     : public IUnknown {
  44  public:
  45   virtual HRESULT STDMETHODCALLTYPE
  46       Notify(ULONG event, NOTIFYITEM* notify_item) = 0;
  47 };
  48
  49 // A class that is capable of reading and writing the state of the notification
  50 // area in the Windows taskbar.  It is used to promote a tray icon from the
  51 // overflow area to the taskbar, and refuses to do anything if the user has
  52 // explicitly marked an icon to be always hidden.
  53 class StatusTrayStateChangerWin : public INotificationCB,
  54                                   public base::win::IUnknownImpl,
  55                                   public base::NonThreadSafe {
  56  public:
  57   StatusTrayStateChangerWin(UINT icon_id, HWND window);
  58
  59   // Call this method to move the icon matching |icon_id| and |window| to the
  60   // taskbar from the overflow area.  This will not make any changes if the
  61   // icon has been set to |PREFERENCE_SHOW_NEVER|, in order to comply with
  62   // the explicit wishes/configuration of the user.
  63   void EnsureTrayIconVisible();
  64
  65   // IUnknown.
  66   ULONG STDMETHODCALLTYPE AddRef() override;
  67   ULONG STDMETHODCALLTYPE Release() override;
  68   HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, PVOID*) override;
  69
  70   // INotificationCB.
  71   // Notify is called in response to RegisterCallback for each current
  72   // entry in Explorer's list of notification area icons, and ever time
  73   // one of them changes, until UnregisterCallback is called or |this|
  74   // is destroyed.
  75   HRESULT STDMETHODCALLTYPE Notify(ULONG, NOTIFYITEM*) override;
  76
  77  protected:
  78   ~StatusTrayStateChangerWin() override;
  79
  80  private:
  81   friend class StatusTrayStateChangerWinTest;
  82
  83   enum InterfaceVersion {
  84     INTERFACE_VERSION_LEGACY = 0,
  85     INTERFACE_VERSION_WIN8,
  86     INTERFACE_VERSION_UNKNOWN
  87   };
  88
  89   // Creates an instance of TrayNotify, and ensures that it supports either
  90   // ITrayNotify or ITrayNotifyWin8.  Returns true on success.
  91   bool CreateTrayNotify();
  92
  93   // Returns the NOTIFYITEM that corresponds to this executable and the
  94   // HWND/ID pair that were used to create the StatusTrayStateChangerWin.
  95   // Internally it calls the appropriate RegisterCallback{Win8,Legacy}.
  96   scoped_ptr<NOTIFYITEM> RegisterCallback();
  97
  98   // Calls RegisterCallback with the appropriate interface required by
  99   // different versions of Windows.  This will result in |notify_item_| being
 100   // updated when a matching item is passed into
 101   // StatusTrayStateChangerWin::Notify.
 102   bool RegisterCallbackWin8();
 103   bool RegisterCallbackLegacy();
 104
 105   // Sends an update to Explorer with the passed NOTIFYITEM.
 106   void SendNotifyItemUpdate(scoped_ptr<NOTIFYITEM> notify_item);
 107
 108   // Storing IUnknown since we will need to use different interfaces
 109   // for different versions of Windows.
 110   base::win::ScopedComPtr<IUnknown> tray_notify_;
 111   InterfaceVersion interface_version_;
 112
 113   // The ID assigned to the notification area icon that we want to manipulate.
 114   const UINT icon_id_;
 115   // The HWND associated with the notification area icon that we want to
 116   // manipulate.  This is an unretained pointer, do not dereference.
 117   const HWND window_;
 118   // Executable name of the current program.  Along with |icon_id_| and
 119   // |window_|, this uniquely identifies a notification area entry to Explorer.
 120   base::string16 file_name_;
 121
 122   // Temporary storage for the matched NOTIFYITEM.  This is necessary because
 123   // Notify doesn't return anything.  The call flow looks like this:
 124   //   TrayNotify->RegisterCallback()
 125   //      ... other COM stack frames ..
 126   //   StatusTrayStateChangerWin->Notify(NOTIFYITEM);
 127   // so we can't just return the notifyitem we're looking for.
 128   scoped_ptr<NOTIFYITEM> notify_item_;
 129
 130   DISALLOW_COPY_AND_ASSIGN(StatusTrayStateChangerWin);
 131 };
 132
 133 #endif  // CHROME_BROWSER_UI_VIEWS_STATUS_ICONS_STATUS_TRAY_STATE_CHANGER_WIN_H_