Screen Lock / Unlock events (#12714)

* initial lock-screen and unlock-screen event implementation for macOS

* Implementation of lock-screen and unlock-screen on windows

atom/browser/api/atom_api_power_monitor.cc

@@ -46,6 +46,9 @@ PowerMonitor::PowerMonitor(v8::Isolate* isolate) {
 #endif
   base::PowerMonitor::Get()->AddObserver(this);
   Init(isolate);
+#if defined(OS_MACOSX) || defined(OS_WIN)
+  InitPlatformSpecificMonitors();
+#endif
 }
 
 PowerMonitor::~PowerMonitor() {

atom/browser/api/atom_api_power_monitor.h

@@ -36,6 +36,10 @@ class PowerMonitor : public mate::TrackableObject<PowerMonitor>,
   void UnblockShutdown();
 #endif
 
+#if defined(OS_MACOSX) || defined(OS_WIN)
+  void InitPlatformSpecificMonitors();
+#endif
+
   // base::PowerObserver implementations:
   void OnPowerStateChange(bool on_battery_power) override;
   void OnSuspend() override;
@@ -47,6 +51,28 @@ class PowerMonitor : public mate::TrackableObject<PowerMonitor>,
                             const ui::IdleCallback& callback);
   void QuerySystemIdleTime(const ui::IdleTimeCallback& callback);
 
+#if defined(OS_WIN)
+  // Static callback invoked when a message comes in to our messaging window.
+  static LRESULT CALLBACK WndProcStatic(HWND hwnd,
+                                        UINT message,
+                                        WPARAM wparam,
+                                        LPARAM lparam);
+
+  LRESULT CALLBACK WndProc(HWND hwnd,
+                           UINT message,
+                           WPARAM wparam,
+                           LPARAM lparam);
+
+  // The window class of |window_|.
+  ATOM atom_;
+
+  // The handle of the module that contains the window procedure of |window_|.
+  HMODULE instance_;
+
+  // The window used for processing events.
+  HWND window_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(PowerMonitor);
 };
 

atom/browser/api/atom_api_power_monitor_mac.mm

@@ -0,0 +1,74 @@
+// Copyright (c) 2013 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_power_monitor.h"
+
+#include <ApplicationServices/ApplicationServices.h>
+#import <Cocoa/Cocoa.h>
+
+@interface MacLockMonitor : NSObject {
+@private
+  std::vector<atom::api::PowerMonitor*> emitters;
+}
+
+- (void)addEmitter:(atom::api::PowerMonitor*)monitor_;
+
+@end
+
+@implementation MacLockMonitor
+
+- (id)init {
+  if ((self = [super init])) {
+    NSDistributedNotificationCenter* distCenter =
+          [NSDistributedNotificationCenter defaultCenter];
+    [distCenter addObserver:self
+                  selector:@selector(onScreenLocked:)
+                      name:@"com.apple.screenIsLocked"
+                    object:nil];
+    [distCenter addObserver:self
+                  selector:@selector(onScreenUnlocked:)
+                      name:@"com.apple.screenIsUnlocked"
+                    object:nil];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [[NSDistributedNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+}
+
+- (void)addEmitter:(atom::api::PowerMonitor*)monitor_ {
+  self->emitters.push_back(monitor_);
+}
+
+- (void)onScreenLocked:(NSNotification*)notification {
+  for (auto& emitter : self->emitters) {
+    emitter->Emit("lock-screen");
+  }
+}
+
+- (void)onScreenUnlocked:(NSNotification*)notification {
+  for (auto& emitter : self->emitters) {
+    emitter->Emit("unlock-screen");
+  }
+}
+
+@end
+
+namespace atom {
+
+namespace api {
+
+static MacLockMonitor* g_lock_monitor = nil;
+
+void PowerMonitor::InitPlatformSpecificMonitors() {
+  if (!g_lock_monitor)
+    g_lock_monitor = [[MacLockMonitor alloc] init];
+  [g_lock_monitor addEmitter:this];
+}
+
+}  // namespace api
+
+}  // namespace atom

atom/browser/api/atom_api_power_monitor_win.cc

@@ -0,0 +1,71 @@
+// Copyright (c) 2013 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_power_monitor.h"
+
+#include "base/win/wrapped_window_proc.h"
+#include "ui/base/win/shell.h"
+#include "ui/gfx/win/hwnd_util.h"
+#include "Wtsapi32.h"
+
+namespace atom {
+
+namespace {
+
+const wchar_t kPowerMonitorWindowClass[] =
+    L"Electron_PowerMonitorHostWindow";
+
+}  // namespace
+
+namespace api {
+
+void PowerMonitor::InitPlatformSpecificMonitors() {
+  WNDCLASSEX window_class;
+  base::win::InitializeWindowClass(
+      kPowerMonitorWindowClass,
+      &base::win::WrappedWindowProc<PowerMonitor::WndProcStatic>, 0, 0, 0,
+      NULL, NULL, NULL, NULL, NULL, &window_class);
+  instance_ = window_class.hInstance;
+  atom_ = RegisterClassEx(&window_class);
+
+  // Create an offscreen window for receiving broadcast messages for the
+  // session lock and unlock events.
+  window_ = CreateWindow(MAKEINTATOM(atom_), 0, 0, 0, 0, 0, 0, HWND_MESSAGE, 0,
+                         instance_, 0);
+  gfx::CheckWindowCreated(window_);
+  gfx::SetWindowUserData(window_, this);
+
+  // Tel windows we want to be notified with session events
+  WTSRegisterSessionNotification(window_, NOTIFY_FOR_THIS_SESSION);
+}
+
+LRESULT CALLBACK PowerMonitor::WndProcStatic(HWND hwnd,
+                                                  UINT message,
+                                                  WPARAM wparam,
+                                                  LPARAM lparam) {
+  PowerMonitor* msg_wnd = reinterpret_cast<PowerMonitor*>(
+      GetWindowLongPtr(hwnd, GWLP_USERDATA));
+  if (msg_wnd)
+    return msg_wnd->WndProc(hwnd, message, wparam, lparam);
+  else
+    return ::DefWindowProc(hwnd, message, wparam, lparam);
+}
+
+LRESULT CALLBACK PowerMonitor::WndProc(HWND hwnd,
+                                            UINT message,
+                                            WPARAM wparam,
+                                            LPARAM lparam) {
+  if (message == WM_WTSSESSION_CHANGE) {
+    if (wparam == WTS_SESSION_LOCK) {
+      Emit("lock-screen");
+    } else if (wparam == WTS_SESSION_UNLOCK) {
+      Emit("unlock-screen");
+    }
+  }
+  return ::DefWindowProc(hwnd, message, wparam, lparam);
+}
+
+}  // namespace api
+
+}  // namespace atom

docs/api/power-monitor.md

@@ -47,6 +47,14 @@ invokes `e.preventDefault()`, Electron will attempt to delay system shutdown in
 order for the app to exit cleanly. If `e.preventDefault()` is called, the app
 should exit as soon as possible by calling something like `app.quit()`.
 
+### Event: 'lock-screen' _macOS_ _Windows_
+
+Emitted when the system is about to lock the screen.
+
+### Event: 'unlock-screen' _macOS_ _Windows_
+
+Emitted as soon as the systems screen is unlocked.
+
 ## Methods
 
 The `powerMonitor` module has the following methods:

electron.gyp

@@ -165,6 +165,9 @@
               # of /SUBSYSTEM:WINDOWS,5.02
               'MinimumRequiredVersion': '5.02',
               'SubSystem': '2',
+              'AdditionalDependencies': [
+                'wtsapi32.lib',
+              ],
             },
           },
           'copies': [

filenames.gypi

@@ -136,6 +136,8 @@
       'atom/browser/api/atom_api_net.h',
       'atom/browser/api/atom_api_notification.cc',
       'atom/browser/api/atom_api_notification.h',
+      'atom/browser/api/atom_api_power_monitor_mac.mm',
+      'atom/browser/api/atom_api_power_monitor_win.cc',
       'atom/browser/api/atom_api_power_monitor.cc',
       'atom/browser/api/atom_api_power_monitor.h',
       'atom/browser/api/atom_api_power_save_blocker.cc',