1 files changed, 115 insertions, 0 deletions
diff --git a/widget/windows/WinEventObserver.h b/widget/windows/WinEventObserver.h
new file mode 100644
index 0000000000..6a267871dd
--- /dev/null
+++ b/widget/windows/WinEventObserver.h
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_WinEventObserver_h
+#define widget_windows_WinEventObserver_h
+
+#include <windows.h>
+
+#include "mozilla/Maybe.h"
+#include "nsISupportsImpl.h"
+#include "nsTHashSet.h"
+
+namespace mozilla {
+
+namespace widget {
+
+class WinEventObserver {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinEventObserver)
+ public:
+  virtual void OnWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                              LPARAM aLParam) {}
+  virtual void Destroy();
+
+ protected:
+  virtual ~WinEventObserver();
+
+  bool mDestroyed = false;
+};
+
+// Uses singleton window to observe events like display status and session
+// change.
+class WinEventHub final {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinEventHub)
+
+ public:
+  // Returns true if the singleton exists (or was created). Will return
+  // false if the singleton couldn't be created, in which case a call
+  // to Get() will return a nullptr. It is safe to call this function
+  // repeatedly.
+  static bool Ensure();
+  static RefPtr<WinEventHub> Get() { return sInstance; }
+
+  void AddObserver(WinEventObserver* aObserver);
+  void RemoveObserver(WinEventObserver* aObserver);
+
+  HWND GetWnd() { return mHWnd; }
+
+ private:
+  WinEventHub();
+  ~WinEventHub();
+
+  static LRESULT CALLBACK WinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                                       LPARAM aLParam);
+
+  bool Initialize();
+  void ProcessWinEventProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
+
+  HWND mHWnd = nullptr;
+  nsTHashSet<nsRefPtrHashKey<WinEventObserver>> mObservers;
+
+  static StaticRefPtr<WinEventHub> sInstance;
+};
+
+class DisplayStatusListener {
+ public:
+  virtual void OnDisplayStateChanged(bool aDisplayOn) = 0;
+};
+
+// Observe Display on/off event
+class DisplayStatusObserver final : public WinEventObserver {
+ public:
+  static already_AddRefed<DisplayStatusObserver> Create(
+      DisplayStatusListener* aListener);
+
+ private:
+  explicit DisplayStatusObserver(DisplayStatusListener* aListener);
+  virtual ~DisplayStatusObserver();
+  void OnWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                      LPARAM aLParam) override;
+
+  DisplayStatusListener* mListener;
+
+  HPOWERNOTIFY mDisplayStatusHandle = nullptr;
+};
+
+class SessionChangeListener {
+ public:
+  virtual void OnSessionChange(WPARAM aStatusCode,
+                               Maybe<bool> aIsCurrentSession) = 0;
+};
+
+// Observe session lock/unlock event
+class SessionChangeObserver : public WinEventObserver {
+ public:
+  static already_AddRefed<SessionChangeObserver> Create(
+      SessionChangeListener* aListener);
+
+ private:
+  explicit SessionChangeObserver(SessionChangeListener* aListener);
+  virtual ~SessionChangeObserver();
+
+  void Initialize();
+  void OnWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                      LPARAM aLParam) override;
+
+  SessionChangeListener* mListener;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_WinEventObserver_h