gecko/netwerk/ipc/NeckoMessageUtils.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * 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
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 *
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * the Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
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 * Contributor(s):
 *   Josh Matthews <josh@joshmatthews.net> (Initial Developer)
 *
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 * either the GNU General Public License Version 2 or later (the "GPL"), or
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#ifndef mozilla_net_NeckoMessageUtils_h
#define mozilla_net_NeckoMessageUtils_h

#include "IPC/IPCMessageUtils.h"
#include "nsStringGlue.h"
#include "nsIURI.h"
#include "nsIIPCSerializable.h"
#include "nsIClassInfo.h"
#include "nsComponentManagerUtils.h"

namespace IPC {

// Since IPDL doesn't have any knowledge of pointers, there's no easy way to
// pass around nsIURI pointers.  This is a very thin wrapper that IPDL can
// easily work with, allowing for conversion to and from an nsIURI pointer.

class URI {
 public:
  URI() : mURI(nsnull) {}
  URI(nsIURI* aURI) : mURI(aURI) {}
  // The contained URI is already addrefed on creation. We don't want another
  // addref when passing it off to its actual owner.
  operator nsCOMPtr<nsIURI>() const { return already_AddRefed<nsIURI>(mURI); }

  friend struct ParamTraits<URI>;
  
 private:
  URI& operator=(URI&);
  nsIURI* mURI;
};
  
template<>
struct ParamTraits<URI>
{
  typedef URI paramType;
  
  static void Write(Message* aMsg, const paramType& aParam)
  {
    bool isNull = !aParam.mURI;
    WriteParam(aMsg, isNull);
    if (isNull)
      return;
    
    nsCOMPtr<nsIIPCSerializable> serializable = do_QueryInterface(aParam.mURI);
    NS_ABORT_IF_FALSE(serializable, "All IPDL URIs must be serializable");
    nsCOMPtr<nsIClassInfo> classInfo = do_QueryInterface(aParam.mURI);
    char cidStr[NSID_LENGTH];
    nsCID cid;
    nsresult rv = classInfo->GetClassIDNoAlloc(&cid);
    NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "All IPDL URIs must report a valid class ID");
    
    cid.ToProvidedString(cidStr);
    WriteParam(aMsg, nsCAutoString(cidStr));
    serializable->Write(aMsg);
  }

  static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
  {
    bool isNull;
    if (!ReadParam(aMsg, aIter, &isNull))
      return false;
    if (isNull) {
      aResult->mURI = nsnull;
      return true;
    }
    
    nsCAutoString cidStr;
    nsCID cid;
    if (!ReadParam(aMsg, aIter, &cidStr) ||
        !cid.Parse(cidStr.get()))
      return false;

    nsCOMPtr<nsIURI> uri = do_CreateInstance(cid);
    if (!uri)
      return false;
    nsCOMPtr<nsIIPCSerializable> serializable = do_QueryInterface(uri);
    if (!serializable || !serializable->Read(aMsg, aIter))
      return false;

    uri.forget(&aResult->mURI);
    return true;
  }

  static void Log(const paramType& aParam, std::wstring* aLog)
  {
    nsIURI* uri = aParam.mURI;
    if (uri) {
      nsCString spec;
      uri->GetSpec(spec);
      aLog->append(StringPrintf(L"[%s]", spec.get()));
    }
    else {
      aLog->append(L"[]");
    }
  }
};

}

#endif // mozilla_net_NeckoMessageUtils_h