Implement first part of supporting global extension commands.

chrome/browser/extensions/global_shortcut_listener_win.cc

+// Copyright (c) 2013 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 "chrome/browser/extensions/global_shortcut_listener_win.h"
+
+#include "base/win/win_util.h"
+#include "content/public/browser/browser_thread.h"
+#include "ui/base/accelerators/accelerator.h"
+#include "ui/events/event_constants.h"
+#include "ui/events/keycodes/keyboard_code_conversion_win.h"
+
+using content::BrowserThread;
+
+namespace {
+
+static base::LazyInstance<extensions::GlobalShortcutListenerWin> instance =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+namespace extensions {
+
+// static
+GlobalShortcutListener* GlobalShortcutListener::GetInstance() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  return instance.Pointer();
+}
+
+GlobalShortcutListenerWin::GlobalShortcutListenerWin()
+    : is_listening_(false) {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+}
+
+GlobalShortcutListenerWin::~GlobalShortcutListenerWin() {
+  if (is_listening_)
+    StopListening();
+}
+
+void GlobalShortcutListenerWin::StartListening() {
+  DCHECK(!is_listening_);  // Don't start twice.
+  DCHECK(!hotkey_ids_.empty());  // Also don't start if no hotkey is registered.
+  gfx::SingletonHwnd::GetInstance()->AddObserver(this);
+  is_listening_ = true;
+}
+
+void GlobalShortcutListenerWin::StopListening() {
+  DCHECK(is_listening_);  // No point if we are not already listening.
+  DCHECK(hotkey_ids_.empty());  // Make sure the map is clean before ending.
+  gfx::SingletonHwnd::GetInstance()->RemoveObserver(this);
+  is_listening_ = false;
+}
+
+void GlobalShortcutListenerWin::OnWndProc(HWND hwnd,
+                                          UINT message,
+                                          WPARAM wparam,
+                                          LPARAM lparam) {
+  if (message != WM_HOTKEY)
+    return;
+
+  int key_code = HIWORD(lparam);
+  int modifiers = 0;
+  modifiers |= (LOWORD(lparam) & MOD_SHIFT) ? ui::EF_SHIFT_DOWN : 0;
+  modifiers |= (LOWORD(lparam) & MOD_ALT) ? ui::EF_ALT_DOWN : 0;
+  modifiers |= (LOWORD(lparam) & MOD_CONTROL) ? ui::EF_CONTROL_DOWN : 0;
+  ui::Accelerator accelerator(
+      ui::KeyboardCodeForWindowsKeyCode(key_code), modifiers);
+
+  instance.Get().NotifyKeyPressed(accelerator);
+}
+
+void GlobalShortcutListenerWin::RegisterAccelerator(
+    const ui::Accelerator& accelerator,
+    GlobalShortcutListener::Observer* observer) {
+  int modifiers = 0;
+  modifiers |= accelerator.IsShiftDown() ? MOD_SHIFT : 0;
+  modifiers |= accelerator.IsCtrlDown() ? MOD_CONTROL : 0;
+  modifiers |= accelerator.IsAltDown() ? MOD_ALT : 0;
+  static int hotkey_id = 0;
+  if (hotkey_id == 0) {
+    // Ensure that the window has been created before calling RegisterHotKey

[Yoyo Zhou, 2013/10/03 22:08:50]

Which window is this?

[Finnur, 2013/10/04 17:57:02]

The singleton-hwnd, but this code is now redundant after addressing Scott's
comments.

+    // because otherwise we'd be calling RegisterHotkey on a NULL window, which
+    // causes problems when unregistering (after the window has been created).
+    gfx::SingletonHwnd::GetInstance()->Init();
+  }
+
+  bool success = !!RegisterHotKey(
+      gfx::SingletonHwnd::GetInstance()->hwnd(),
+      hotkey_id,
+      modifiers,
+      accelerator.key_code());
+
+  if (!success) {
+    // Most likely error: 1409 (Hotkey already registered).
+    LOG(ERROR) << "RegisterHotKey failed, error: " << GetLastError();
+    return;
+  }
+
+  hotkey_ids_[accelerator] = hotkey_id++;
+  GlobalShortcutListener::RegisterAccelerator(accelerator, observer);
+}
+
+void GlobalShortcutListenerWin::UnregisterAccelerator(
+    const ui::Accelerator& accelerator,
+    GlobalShortcutListener::Observer* observer) {
+  // We may get asked to unregister something that we couldn't register (for
+  // example if the shortcut was already taken by another app), so we
+  // need to handle that gracefully.
+  HotkeyIdMap::iterator it = hotkey_ids_.find(accelerator);
+  if (it == hotkey_ids_.end())
+    return;
+
+  UnregisterHotKey(gfx::SingletonHwnd::GetInstance()->hwnd(), it->second);
+  hotkey_ids_.erase(it);
+
+  GlobalShortcutListener::UnregisterAccelerator(accelerator, observer);
+}
+
+}  // namespace extensions