gecko/ipc/glue/IPCMessageUtils.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla IPC.
 *
 * The Initial Developer of the Original Code is
 *   Ben Turner <bent.mozilla@gmail.com>.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
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 * either the GNU General Public License Version 2 or later (the "GPL"), or
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 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * ***** END LICENSE BLOCK ***** */

#ifndef __IPC_GLUE_IPCMESSAGEUTILS_H__
#define __IPC_GLUE_IPCMESSAGEUTILS_H__

#include "chrome/common/ipc_message_utils.h"

#include "prtypes.h"
#include "nsStringGlue.h"
#include "nsTArray.h"

#include "IPCMessageStart.h"

COMPILE_ASSERT(LastMsgIndex <= 16, need_to_update_IPC_MESSAGE_MACRO);

namespace IPC {

template <>
struct ParamTraits<nsACString>
{
  typedef nsACString paramType;

  static void Write(Message* aMsg, const paramType& aParam)
  {
    bool isVoid = aParam.IsVoid();
    aMsg->WriteBool(isVoid);

    if (isVoid)
      // represents a NULL pointer
      return;

    PRUint32 length = aParam.Length();
    WriteParam(aMsg, length);
    aMsg->WriteBytes(aParam.BeginReading(), length);
  }

  static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
  {
    bool isVoid;
    if (!aMsg->ReadBool(aIter, &isVoid))
      return false;

    if (isVoid) {
      aResult->SetIsVoid(PR_TRUE);
      return true;
    }

    PRUint32 length;
    if (ReadParam(aMsg, aIter, &length)) {
      const char* buf;
      if (aMsg->ReadBytes(aIter, &buf, length)) {
        aResult->Assign(buf, length);
        return true;
      }
    }
    return false;
  }

  static void Log(const paramType& aParam, std::wstring* aLog)
  {
    if (aParam.IsVoid())
      aLog->append(L"(NULL)");
    else
      aLog->append(UTF8ToWide(aParam.BeginReading()));
  }
};

template <>
struct ParamTraits<nsAString>
{
  typedef nsAString paramType;

  static void Write(Message* aMsg, const paramType& aParam)
  {
    bool isVoid = aParam.IsVoid();
    aMsg->WriteBool(isVoid);

    if (isVoid)
      // represents a NULL pointer
      return;

    PRUint32 length = aParam.Length();
    WriteParam(aMsg, length);
    aMsg->WriteBytes(aParam.BeginReading(), length * sizeof(PRUnichar));
  }

  static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
  {
    bool isVoid;
    if (!aMsg->ReadBool(aIter, &isVoid))
      return false;

    if (isVoid) {
      aResult->SetIsVoid(PR_TRUE);
      return true;
    }

    PRUint32 length;
    if (ReadParam(aMsg, aIter, &length)) {
      const PRUnichar* buf;
      if (aMsg->ReadBytes(aIter, reinterpret_cast<const char**>(&buf),
                       length * sizeof(PRUnichar))) {
        aResult->Assign(buf, length);
        return true;
      }
    }
    return false;
  }

  static void Log(const paramType& aParam, std::wstring* aLog)
  {
    if (aParam.IsVoid())
      aLog->append(L"(NULL)");
    else {
#ifdef WCHAR_T_IS_UTF16
      aLog->append(reinterpret_cast<const wchar_t*>(aParam.BeginReading()));
#else
      PRUint32 length = aParam.Length();
      for (PRUint32 index = 0; index < length; index++) {
        aLog->push_back(std::wstring::value_type(aParam[index]));
      }
#endif
    }
  }
};

template <>
struct ParamTraits<nsCString> : ParamTraits<nsACString>
{
  typedef nsCString paramType;
};

template <>
struct ParamTraits<nsString> : ParamTraits<nsAString>
{
  typedef nsString paramType;
};

template <typename E>
struct ParamTraits<nsTArray<E> >
{
  typedef nsTArray<E> paramType;

  static void Write(Message* aMsg, const paramType& aParam)
  {
    PRUint32 length = aParam.Length();
    WriteParam(aMsg, length);
    for (PRUint32 index = 0; index < length; index++) {
      WriteParam(aMsg, aParam[index]);
    }
  }

  static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
  {
    PRUint32 length;
    if (!ReadParam(aMsg, aIter, &length)) {
      return false;
    }

    // sizeof(E) only makes a limited amount of sense here as it may not have
    // anything to do with the amount of data needed to serialize an object of
    // type E. Neverheless trying to allocate a huge chunk of memory here if
    // we receive a bad message must also be avoided and so we check before we
    // call SetLength. If we don't have enough space in the message then we do
    // individual allocations to be safe.
    if (aMsg->IteratorHasRoomFor(*aIter, length * sizeof(E))) {
      if (!aResult->SetLength(length)) {
        return false;
      }
      for (PRUint32 index = 0; index < length; index++) {
        E& element = aResult->ElementAt(index);
        if (!ReadParam(aMsg, aIter, &element)) {
          return false;
        }
      }
    }
    else {
      for (PRUint32 index = 0; index < length; index++) {
        E* element = aResult->AppendElement();
        if (!(element && ReadParam(aMsg, aIter, element))) {
          return false;
        }
      }
    }

    return true;
  }

  static void Log(const paramType& aParam, std::wstring* aLog)
  {
    for (PRUint32 index = 0; index < aParam.Length(); index++) {
      if (index) {
        aLog->append(L" ");
      }
      LogParam(aParam[index], aLog);
    }
  }
};

} /* namespace IPC */

#endif /* __IPC_GLUE_IPCMESSAGEUTILS_H__ */