Automatically remap Command key on an Apple keyboard to Control [part 2 of 2 - Chrome part]

chrome/browser/ui/views/ash/key_rewriter.cc

+// Copyright (c) 2012 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/ui/views/ash/key_rewriter.h"
+
+#include <vector>
+
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "ui/aura/event.h"
+#include "ui/base/keycodes/keyboard_codes.h"
+
+#if defined(OS_CHROMEOS)
+#include "base/chromeos/chromeos_version.h"
+#include "chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h"
+#include "ui/base/keycodes/keyboard_code_conversion_x.h"
+#include "ui/base/x/x11_util.h"
+
+#include <X11/extensions/XInput2.h>
+#include <X11/keysymdef.h>
+#include <X11/Xlib.h>
+#endif
+
+namespace {
+
+const int kBadDeviceId = -1;
+
+#if defined(OS_CHROMEOS)
+// TODO(yusukes): It's better not to use the hard coded values. However, I don't
+// know a good way (except scanning /usr/share/X11/xkb/keycodes/evdev in .gyp
+// which is also hacky) to get key codes from X key symbols like XK_Super_L.
+const unsigned int kKeyCodeSuperL = 133;  // Left Command or Windows key.
+const unsigned int kKeyCodeSuperR = 134;  // Right Command or Windows key.
+const unsigned int kKeyCodeControlL = 37;  // Left Control key.
+const unsigned int kKeyCodeControlR = 105;  // Right Control key.
+#endif
+
+}  // namespace
+
+KeyRewriter::KeyRewriter() : last_device_id_(kBadDeviceId) {
+#if defined(OS_CHROMEOS)
+  if (base::chromeos::IsRunningOnChromeOS()) {
+    chromeos::XInputHierarchyChangedEventListener::GetInstance()
+        ->AddObserver(this);
+  }
+#endif
+}
+KeyRewriter::~KeyRewriter() {
+#if defined(OS_CHROMEOS)
+  if (base::chromeos::IsRunningOnChromeOS()) {
+    chromeos::XInputHierarchyChangedEventListener::GetInstance()
+        ->RemoveObserver(this);
+  }
+#endif
+}
+
+KeyRewriter::DeviceType KeyRewriter::DeviceAddedForTesting(
+    int device_id,
+    const std::string& device_name) {
+  return DeviceAddedInternal(device_id, device_name);
+}
+
+// static
+KeyRewriter::DeviceType KeyRewriter::GetDeviceType(
+    const std::string& device_name) {
+  std::vector<std::string> tokens;
+  Tokenize(device_name, " .", &tokens);
+
+  // If the |device_name| contains the two words, "apple" and "keyboard", treat
+  // it as an Apple keyboard.
+  bool found_apple = false;
+  bool found_keyboard = false;
+  for (size_t i = 0; i < tokens.size(); ++i) {
+    if (!found_apple && LowerCaseEqualsASCII(tokens[i], "apple"))
+      found_apple = true;
+    if (!found_keyboard && LowerCaseEqualsASCII(tokens[i], "keyboard"))
+      found_keyboard = true;
+    if (found_apple && found_keyboard)
+      return kDeviceAppleKeyboard;
+  }
+
+  return kDevicePcKeyboard;
+}
+
+void KeyRewriter::RewriteCommandToControlForTesting(aura::KeyEvent* event) {
+  RewriteCommandToControl(event);
+}
+
+ash::KeyRewriterDelegate::Action KeyRewriter::RewriteOrFilterKeyEvent(
+    aura::KeyEvent* event) {
+  const ash::KeyRewriterDelegate::Action kActionRewrite =
+      ash::KeyRewriterDelegate::ACTION_REWRITE_EVENT;
+  if (!event->HasNativeEvent()) {
+    // Do not handle a fabricated event generated by tests.
+    return kActionRewrite;
+  }
+
+  RewriteCommandToControl(event);
+  // TODO(yusukes): Implement crbug.com/115112 (Search/Ctrl/Alt remapping) and
+  // crosbug.com/27167 (allow sending function keys) here.
+
+  return kActionRewrite;  // Do not drop the event.
+}
+
+#if defined(OS_CHROMEOS)
+void KeyRewriter::DeviceAdded(int device_id) {
+  DCHECK_NE(XIAllDevices, device_id);
+  DCHECK_NE(XIAllMasterDevices, device_id);
+  if (device_id == XIAllDevices || device_id == XIAllMasterDevices) {
+    LOG(ERROR) << "Unexpected device_id passed: " << device_id;
+    return;
+  }
+
+  int ndevices_return = 0;
+  XIDeviceInfo* device_info = XIQueryDevice(ui::GetXDisplay(),
+                                            device_id,
+                                            &ndevices_return);
+
+  // Since |device_id| is neither XIAllDevices nor XIAllMasterDevices,
+  // The number of devices found should be either 0 (not found) or 1.
+  if (!device_info) {
+    LOG(ERROR) << "XIQueryDevice: Device ID " << device_id << " is unknown.";
+    return;
+  }
+
+  DCHECK_EQ(1, ndevices_return);
+  for (int i = 0; i < ndevices_return; ++i) {
+    DCHECK_EQ(device_id, device_info[i].deviceid);  // see the comment above.
+    DCHECK(device_info[i].name);
+    DeviceAddedInternal(device_info[i].deviceid, device_info[i].name);
+  }
+
+  XIFreeDeviceInfo(device_info);
+}
+
+void KeyRewriter::KeyPressedOrReleased(int device_id) {
+  std::map<int, DeviceType>::const_iterator iter =
+      device_id_to_type_.find(device_id);
+  if (iter == device_id_to_type_.end()) {
+    // |device_id| is unknown. This means the device was connected before
+    // booting the OS. Query the name of the device and add it to the map.
+    DeviceAdded(device_id);
+  }
+
+  last_device_id_ = device_id;
+}
+#endif
+
+void KeyRewriter::RewriteCommandToControl(aura::KeyEvent* event) {
+  if (last_device_id_ == kBadDeviceId)
+    return;
+
+  // Check the device which generated the |event|.
+  std::map<int, DeviceType>::const_iterator iter =
+      device_id_to_type_.find(last_device_id_);
+  if (iter == device_id_to_type_.end()) {
+    LOG(ERROR) << "Device ID " << last_device_id_ << " is unknown.";
+    return;
+  }
+
+  const DeviceType type = iter->second;
+  if (type != kDeviceAppleKeyboard)
+    return;
+
+#if defined(OS_CHROMEOS)
+  XEvent* xev = event->native_event();
+  XKeyEvent* xkey = &(xev->xkey);
+
+  // Remap Command key on an Apple keyboard to Control.
+  // Handle Command-L key press/release.
+  if (xkey->keycode == kKeyCodeSuperL)
+    xkey->keycode = kKeyCodeControlL;
+  // Handle Command-R key press/release.
+  if (xkey->keycode == kKeyCodeSuperR)
+    xkey->keycode = kKeyCodeControlR;
+  // Handle Command+<other-key> press/release.
+  if (xkey->state & Mod4Mask) {
+    // Mod4 is Windows key on a PC keyboard or Command key on an Apple keyboard.
+    xkey->state &= ~Mod4Mask;
+    xkey->state |= ControlMask;
+  }
+
+  DCHECK_NE(ui::VKEY_LWIN, ui::KeyboardCodeFromXKeyEvent(xev));
+  DCHECK_NE(ui::VKEY_RWIN, ui::KeyboardCodeFromXKeyEvent(xev));
+#else
+  // TODO(yusukes): Support Ash on other platforms if needed.
+  NOTIMPLEMENTED();
+#endif
+}
+
+KeyRewriter::DeviceType KeyRewriter::DeviceAddedInternal(
+    int device_id,
+    const std::string& device_name) {
+  const DeviceType type = KeyRewriter::GetDeviceType(device_name);
+  if (type == kDeviceAppleKeyboard) {
+    LOG(WARNING) << "An Apple keyboard '" << device_name << "' is connected: "
+                 << "device_id=" << device_id;
+  }
+  // Always overwrite the existing device_id since the X server may reuse a
+  // device id for an unattached device.
+  device_id_to_type_[device_id] = type;
+  return type;
+}