nsBidiKeyboard.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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/. */

#include <stdio.h>
#include "nsBidiKeyboard.h"
#include "WidgetUtils.h"
#include "nsIWidget.h"
#include <tchar.h>

NS_IMPL_ISUPPORTS(nsBidiKeyboard, nsIBidiKeyboard)

nsBidiKeyboard::nsBidiKeyboard() : nsIBidiKeyboard() { Reset(); }

nsBidiKeyboard::~nsBidiKeyboard() {}

NS_IMETHODIMP nsBidiKeyboard::Reset() {
  mInitialized = false;
  mHaveBidiKeyboards = false;
  mLTRKeyboard[0] = '\0';
  mRTLKeyboard[0] = '\0';
  mCurrentLocaleName[0] = '\0';
  return NS_OK;
}

NS_IMETHODIMP nsBidiKeyboard::IsLangRTL(bool* aIsRTL) {
  *aIsRTL = false;

  nsresult result = SetupBidiKeyboards();
  if (NS_FAILED(result)) return result;

  HKL currentLocale;

  currentLocale = ::GetKeyboardLayout(0);
  *aIsRTL = IsRTLLanguage(currentLocale);

  if (!::GetKeyboardLayoutNameW(mCurrentLocaleName)) return NS_ERROR_FAILURE;

  NS_ASSERTION(*mCurrentLocaleName,
               "GetKeyboardLayoutName return string length == 0");
  NS_ASSERTION((wcslen(mCurrentLocaleName) < KL_NAMELENGTH),
               "GetKeyboardLayoutName return string length >= KL_NAMELENGTH");

  // The language set by the user overrides the default language for that
  // direction
  if (*aIsRTL) {
    wcsncpy(mRTLKeyboard, mCurrentLocaleName, KL_NAMELENGTH);
    mRTLKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
  } else {
    wcsncpy(mLTRKeyboard, mCurrentLocaleName, KL_NAMELENGTH);
    mLTRKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
  }

  NS_ASSERTION((wcslen(mRTLKeyboard) < KL_NAMELENGTH),
               "mLTRKeyboard has string length >= KL_NAMELENGTH");
  NS_ASSERTION((wcslen(mLTRKeyboard) < KL_NAMELENGTH),
               "mRTLKeyboard has string length >= KL_NAMELENGTH");
  return NS_OK;
}

NS_IMETHODIMP nsBidiKeyboard::GetHaveBidiKeyboards(bool* aResult) {
  NS_ENSURE_ARG_POINTER(aResult);

  nsresult result = SetupBidiKeyboards();
  if (NS_FAILED(result)) return result;

  *aResult = mHaveBidiKeyboards;
  return NS_OK;
}

// Get the list of keyboard layouts available in the system
// Set mLTRKeyboard to the first LTR keyboard in the list and mRTLKeyboard to
// the first RTL keyboard in the list These defaults will be used unless the
// user explicitly sets something else.
nsresult nsBidiKeyboard::SetupBidiKeyboards() {
  if (mInitialized) return mHaveBidiKeyboards ? NS_OK : NS_ERROR_FAILURE;

  int keyboards;
  HKL far* buf;
  HKL locale;
  wchar_t localeName[KL_NAMELENGTH];
  bool isLTRKeyboardSet = false;
  bool isRTLKeyboardSet = false;

  // GetKeyboardLayoutList with 0 as first parameter returns the number of
  // keyboard layouts available
  keyboards = ::GetKeyboardLayoutList(0, nullptr);
  if (!keyboards) return NS_ERROR_FAILURE;

  // allocate a buffer to hold the list
  buf = (HKL far*)malloc(keyboards * sizeof(HKL));
  if (!buf) return NS_ERROR_OUT_OF_MEMORY;

  // Call again to fill the buffer
  if (::GetKeyboardLayoutList(keyboards, buf) != keyboards) {
    free(buf);
    return NS_ERROR_UNEXPECTED;
  }

  // Go through the list and pick a default LTR and RTL keyboard layout
  while (keyboards--) {
    locale = buf[keyboards];
    if (IsRTLLanguage(locale)) {
      _snwprintf(mRTLKeyboard, KL_NAMELENGTH, L"%.*x", KL_NAMELENGTH - 1,
                 LANGIDFROMLCID((DWORD_PTR)locale));
      isRTLKeyboardSet = true;
    } else {
      _snwprintf(mLTRKeyboard, KL_NAMELENGTH, L"%.*x", KL_NAMELENGTH - 1,
                 LANGIDFROMLCID((DWORD_PTR)locale));
      isLTRKeyboardSet = true;
    }
  }
  free(buf);
  mInitialized = true;

  // If there is not at least one keyboard of each directionality, Bidi
  // keyboard functionality will be disabled.
  mHaveBidiKeyboards = (isRTLKeyboardSet && isLTRKeyboardSet);
  if (!mHaveBidiKeyboards) return NS_ERROR_FAILURE;

  // Get the current keyboard layout and use it for either mRTLKeyboard or
  // mLTRKeyboard as appropriate. If the user has many keyboard layouts
  // installed this prevents us from arbitrarily resetting the current
  // layout (bug 80274)
  locale = ::GetKeyboardLayout(0);
  if (!::GetKeyboardLayoutNameW(localeName)) return NS_ERROR_FAILURE;

  NS_ASSERTION(*localeName, "GetKeyboardLayoutName return string length == 0");
  NS_ASSERTION((wcslen(localeName) < KL_NAMELENGTH),
               "GetKeyboardLayout return string length >= KL_NAMELENGTH");

  if (IsRTLLanguage(locale)) {
    wcsncpy(mRTLKeyboard, localeName, KL_NAMELENGTH);
    mRTLKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
  } else {
    wcsncpy(mLTRKeyboard, localeName, KL_NAMELENGTH);
    mLTRKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
  }

  NS_ASSERTION(*mRTLKeyboard, "mLTRKeyboard has string length == 0");
  NS_ASSERTION(*mLTRKeyboard, "mLTRKeyboard has string length == 0");

  return NS_OK;
}

// Test whether the language represented by this locale identifier is a
//  right-to-left language, using bit 123 of the Unicode subset bitfield in
//  the LOCALESIGNATURE
// See
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/intl/unicode_63ub.asp
bool nsBidiKeyboard::IsRTLLanguage(HKL aLocale) {
  LOCALESIGNATURE localesig;
  return (::GetLocaleInfoW(PRIMARYLANGID((DWORD_PTR)aLocale),
                           LOCALE_FONTSIGNATURE, (LPWSTR)&localesig,
                           (sizeof(localesig) / sizeof(WCHAR))) &&
          (localesig.lsUsb[3] & 0x08000000));
}

// static
void nsBidiKeyboard::OnLayoutChange() {
  mozilla::widget::WidgetUtils::SendBidiKeyboardInfoToContent();
}

// static
already_AddRefed<nsIBidiKeyboard> nsIWidget::CreateBidiKeyboardInner() {
  return do_AddRef(new nsBidiKeyboard());
}