widget/nsTransferable.h
author Rob Wu <rob@robwu.nl>
Sun, 25 Feb 2018 17:36:08 +0100
changeset 406670 5469af7e5a36d3c34b876ba6fccf17647bc258a7
parent 406668 28a5bbda5231a3d0932fe80fdf0783e880ef2250
child 440644 2852663b840e9a4348130dcbf8efdd494f738a76
permissions -rw-r--r--
Bug 335545 - Make DataStruct non-copyable r=mstange DataStruct cannot safely be copied if its mCacheFD member is set. Currently there is no code for this case, but to avoid problems later, mark the copy and assignment constructors private and delete them. A move-constructor was added to compensate for the deleted copy constructor. nsTransferable::AddDataFlavor uses this new constructor instead of the previous implicit default copy constructor. MozReview-Commit-ID: 3N5xjFXOUKB

/* -*- 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/. */

#ifndef nsTransferable_h__
#define nsTransferable_h__

#include "nsIFormatConverter.h"
#include "nsITransferable.h"
#include "nsCOMPtr.h"
#include "nsString.h"
#include "nsTArray.h"
#include "nsIPrincipal.h"
#include "prio.h"

class nsIMutableArray;

//
// DataStruct
//
// Holds a flavor (a mime type) that describes the data and the associated data.
//
struct DataStruct
{
  explicit DataStruct ( const char* aFlavor )
    : mDataLen(0), mCacheFD(nullptr), mFlavor(aFlavor) { }
  DataStruct(DataStruct&& aRHS);
  ~DataStruct();
  
  const nsCString& GetFlavor() const { return mFlavor; }
  void SetData( nsISupports* inData, uint32_t inDataLen, bool aIsPrivateData );
  void GetData( nsISupports** outData, uint32_t *outDataLen );
  bool IsDataAvailable() const { return mData ? mDataLen > 0 : mCacheFD != nullptr; }
  
protected:

  enum {
    // The size of data over which we write the data to disk rather than
    // keep it around in memory.
    kLargeDatasetSize = 1000000        // 1 million bytes
  };
  
  nsresult WriteCache(nsISupports* aData, uint32_t aDataLen );
  nsresult ReadCache(nsISupports** aData, uint32_t* aDataLen );
  
  // mData + mDataLen OR mCacheFD should be used, not both.
  nsCOMPtr<nsISupports> mData;   // OWNER - some varient of primitive wrapper
  uint32_t mDataLen;
  PRFileDesc* mCacheFD;
  const nsCString mFlavor;

private:
  DataStruct(const DataStruct&) = delete;
  DataStruct& operator=(const DataStruct&) = delete;

};

/**
 * XP Transferable wrapper
 */

class nsTransferable : public nsITransferable
{
public:

  nsTransferable();

    // nsISupports
  NS_DECL_ISUPPORTS
  NS_DECL_NSITRANSFERABLE

protected:
  virtual ~nsTransferable();

    // get flavors w/out converter
  already_AddRefed<nsIMutableArray> GetTransferDataFlavors();
 
  nsTArray<DataStruct> mDataArray;
  nsCOMPtr<nsIFormatConverter> mFormatConv;
  bool mPrivateData;
  nsCOMPtr<nsIPrincipal> mRequestingPrincipal;
  nsContentPolicyType mContentPolicyType;
#if DEBUG
  bool mInitialized;
#endif

};

#endif // nsTransferable_h__