Build key map DomCodeToKey() for Windows

ui/events/keycodes/keyboard_lookup_win.cc

+// Copyright (c) 2015 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 "ui/events/keycodes/keyboard_lookup_win.h"
+
+#include "base/logging.h"
+#include "base/macros.h"
+
+namespace ui {
+
+const EventFlags WindowsKeyboardLookup::event_flags_index[] = {

[dtapuska, 2016/01/21 01:59:36]

Move to annonymous scope; and add a static_assert that
arraysize(event_flags_index) < the number of modifiers defined in
WIndowsKeyboardLookup..

[chongz, 2016/01/21 15:47:40]

Acknowledged.

+  EF_CAPS_LOCK_DOWN,
+  EF_SHIFT_DOWN,
+  EF_CONTROL_DOWN,
+  EF_ALT_DOWN,
+  EF_COMMAND_DOWN,
+  EF_ALTGR_DOWN,
+  EF_NUM_LOCK_DOWN,
+  EF_SCROLL_LOCK_DOWN
+};
+
+WindowsKeyboardLookup* WindowsKeyboardLookup::Create(HKL alayout) {
+  WindowsKeyboardLookup *tmp = new WindowsKeyboardLookup();
+  tmp->CheckOrLoadLayout(alayout);
+  return tmp;
+}
+
+DomKey WindowsKeyboardLookup::VirtualKeyToCurrentLayoutDomKey(
+    KeyboardCode vkcode,
+    int event_flags) {
+  GetInstance()->CheckOrLoadLayout(::GetKeyboardLayout(0));
+  return GetInstance()->VirtualKeyToDomKey(vkcode, event_flags);
+}
+
+DomKey WindowsKeyboardLookup::VirtualKeyToDomKey(KeyboardCode vkcode,
+                                                 int event_flags) const {
+  if (vkcode >= kMaxVirtualKeyCode)
+    return DomKey::NONE;
+  size_t eindex = GetEventFlagsIndex(event_flags);
+  return lookup_table_[vkcode][eindex];
+}
+
+void WindowsKeyboardLookup::CheckOrLoadLayout(HKL alayout) {
+  if (alayout == keyboard_layout_)
+    return;
+  keyboard_layout_ = alayout;
+
+  BYTE keyboard_state[256];
+  BYTE original_keyboard_state[256];
+
+  memset(keyboard_state, 0, sizeof(keyboard_state));
+  ::GetKeyboardState(original_keyboard_state);
+
+  for (size_t eindex = 0; eindex < kMaxKeyboardModifier; ++eindex) {
+    SetModifierState(keyboard_state, EventFlagsFromIndex(eindex));
+    for (size_t vk = 0; vk < kMaxVirtualKeyCode; ++vk) {
+      wchar_t unibuff[5];
+
+      int rv = ::ToUnicodeEx(vk, 0, keyboard_state, unibuff, arraysize(unibuff),
+                             0, keyboard_layout_);
+
+      if (rv < 0) {
+        // Dead key, repeat twice to get character representation
+        rv = ::ToUnicodeEx(vk, 0, keyboard_state, unibuff, arraysize(unibuff),
+                           0, keyboard_layout_);
+        // Must be a repeat of dead key character
+        DCHECK(rv == 2);
+        lookup_table_[vk][eindex] = DomKey::DeadKeyFromCombiningCharacter(
+                                     unibuff[0]);
+      } else if (rv >= 1) {
+        lookup_table_[vk][eindex] = DomKey::FromCharacter(unibuff[0]);
+      }
+    }
+  }
+  ::SetKeyboardState(original_keyboard_state);
+}
+
+void WindowsKeyboardLookup::SetModifierState(BYTE *keyboard_state,
+                                             int event_flags) const {
+  // Trying to match system_event_state_lookup.cc
+  if (event_flags & EF_SHIFT_DOWN) {
+    keyboard_state[VK_SHIFT] |= 0x80;
+  } else {
+    keyboard_state[VK_SHIFT] &= ~0x80;
+    keyboard_state[VK_LSHIFT] &= ~0x80;
+    keyboard_state[VK_RSHIFT] &= ~0x80;
+  }
+
+  if (event_flags & EF_CONTROL_DOWN) {
+    keyboard_state[VK_CONTROL] |= 0x80;
+  } else {
+    keyboard_state[VK_CONTROL] &= ~0x80;
+    keyboard_state[VK_LCONTROL] &= ~0x80;
+    keyboard_state[VK_RCONTROL] &= ~0x80;
+  }
+
+  if (event_flags & EF_ALT_DOWN) {
+    keyboard_state[VK_MENU] |= 0x80;
+  } else {
+    keyboard_state[VK_MENU] &= ~0x80;
+    keyboard_state[VK_LMENU] &= ~0x80;
+    keyboard_state[VK_RMENU] &= ~0x80;
+  }
+
+  if (event_flags & EF_ALTGR_DOWN) {
+    keyboard_state[VK_MENU] |= 0x80;
+    keyboard_state[VK_CONTROL] |= 0x80;
+  } else {
+    // Windows does not have a specific key code for AltGr
+  }
+
+  if (event_flags & EF_COMMAND_DOWN) {
+    keyboard_state[VK_LWIN] |= 0x80;
+  } else {
+    keyboard_state[VK_LWIN] &= ~0x80;
+    keyboard_state[VK_RWIN] &= ~0x80;
+  }
+
+  if (event_flags & EF_CAPS_LOCK_DOWN) {
+    keyboard_state[VK_CAPITAL] |= 0x01;
+  } else {
+    keyboard_state[VK_CAPITAL] &= ~0x01;
+  }
+
+  if (event_flags & EF_NUM_LOCK_DOWN) {
+    keyboard_state[VK_NUMLOCK] |= 0x01;
+  } else {
+    keyboard_state[VK_NUMLOCK] &= ~0x01;
+  }
+
+  if (event_flags & EF_SCROLL_LOCK_DOWN) {
+    keyboard_state[VK_SCROLL] |= 0x01;
+  } else {
+    keyboard_state[VK_SCROLL] &= ~0x01;
+  }
+
+  // TODO(chongz): EF_EXTENDED
+}
+
+size_t WindowsKeyboardLookup::GetEventFlagsIndex(int event_flags) const {
+  size_t index = 0;
+  for (size_t i = 0; i < arraysize(event_flags_index); ++i) {
+    if (event_flags & event_flags_index[i])
+      index |= 1 << i;
+  }
+  return index;
+}
+
+int WindowsKeyboardLookup::EventFlagsFromIndex(size_t index) const {
+  int event_flags = EF_NONE;
+  for (size_t i = 0; i < arraysize(event_flags_index); ++i) {
+    if (index & (1 << i))
+      event_flags |= event_flags_index[i];
+  }
+  return event_flags;
+}
+
+WindowsKeyboardLookup* WindowsKeyboardLookup::GetInstance() {
+  static WindowsKeyboardLookup* instance = nullptr;

[dtapuska, 2016/01/21 01:59:36]

You can actually get rid of the GetInstance and just use a member variable.

static WindowsKeyboardLookup s_instance;

And then call s_instance.CheckOrLoadLayout in the
VirtualKeyToCurrentLayoutDomKey

then you'll avoid two calls to GetKeyboardLayout(0) on the first call. 

[chongz, 2016/01/21 15:47:40]

Acknowledged.

+  if (instance == nullptr)
+    instance = WindowsKeyboardLookup::Create(::GetKeyboardLayout(0));
+  return instance;
+}
+
+}  // namespace ui