gecko-dev/widget/nsTransferable.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/. */

/*
Notes to self:

- at some point, strings will be accessible from JS, so we won't have to wrap
   flavors in an nsISupportsCString. Until then, we're kinda stuck with
   this crappy API of nsIArrays.

*/


#include "nsTransferable.h"
#include "nsAnonymousTemporaryFile.h"
#include "nsArray.h"
#include "nsArrayUtils.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "nsTArray.h"
#include "nsIFormatConverter.h"
#include "nsIContentPolicy.h"
#include "nsIComponentManager.h"
#include "nsCOMPtr.h"
#include "nsXPCOM.h"
#include "nsISupportsPrimitives.h"
#include "nsMemory.h"
#include "nsPrimitiveHelpers.h"
#include "nsDirectoryServiceDefs.h"
#include "nsDirectoryService.h"
#include "nsCRT.h"
#include "nsNetUtil.h"
#include "nsIOutputStream.h"
#include "nsIInputStream.h"
#include "nsIWeakReferenceUtils.h"
#include "nsILoadContext.h"
#include "mozilla/UniquePtr.h"

NS_IMPL_ISUPPORTS(nsTransferable, nsITransferable)

size_t GetDataForFlavor (const nsTArray<DataStruct>& aArray,
                           const char* aDataFlavor)
{
  for (size_t i = 0 ; i < aArray.Length () ; ++i) {
    if (aArray[i].GetFlavor().Equals (aDataFlavor))
      return i;
  }

  return aArray.NoIndex;
}

DataStruct::DataStruct(DataStruct&& aRHS)
  : mData(aRHS.mData.forget()),
    mDataLen(aRHS.mDataLen),
    mCacheFD(aRHS.mCacheFD),
    mFlavor(aRHS.mFlavor)
{
  aRHS.mCacheFD = nullptr;
}

//-------------------------------------------------------------------------
DataStruct::~DataStruct()
{
  if (mCacheFD) {
    PR_Close(mCacheFD);
  }
}

//-------------------------------------------------------------------------
void
DataStruct::SetData ( nsISupports* aData, uint32_t aDataLen, bool aIsPrivateData )
{
  // Now, check to see if we consider the data to be "too large"
  // as well as ensuring that private browsing mode is disabled
  if (aDataLen > kLargeDatasetSize && !aIsPrivateData) {
    // if so, cache it to disk instead of memory
    if (NS_SUCCEEDED(WriteCache(aData, aDataLen))) {
      // Clear previously set small data.
      mData = nullptr;
      mDataLen = 0;
      return;
    }
    NS_WARNING("Oh no, couldn't write data to the cache file");
  }

  if (mCacheFD) {
    // Clear previously set big data.
    PR_Close(mCacheFD);
    mCacheFD = nullptr;
  }

  mData    = aData;
  mDataLen = aDataLen;
}


//-------------------------------------------------------------------------
void
DataStruct::GetData ( nsISupports** aData, uint32_t *aDataLen )
{
  // check here to see if the data is cached on disk
  if (mCacheFD) {
    // if so, read it in and pass it back
    // ReadCache creates memory and copies the data into it.
    if ( NS_SUCCEEDED(ReadCache(aData, aDataLen)) )
      return;
    else {
      // oh shit, something went horribly wrong here.
      NS_WARNING("Oh no, couldn't read data in from the cache file");
      *aData = nullptr;
      *aDataLen = 0;
      PR_Close(mCacheFD);
      mCacheFD = nullptr;
      return;
    }
  }

  *aData = mData;
  if ( mData )
    NS_ADDREF(*aData);
  *aDataLen = mDataLen;
}


//-------------------------------------------------------------------------
nsresult
DataStruct::WriteCache(nsISupports* aData, uint32_t aDataLen)
{
  nsresult rv;
  if (!mCacheFD) {
    rv = NS_OpenAnonymousTemporaryFile(&mCacheFD);
    if (NS_FAILED(rv)) {
      return NS_ERROR_FAILURE;
    }
  } else if (PR_Seek64(mCacheFD, 0, PR_SEEK_SET) == -1) {
    return NS_ERROR_FAILURE;
  }

  // write out the contents of the clipboard to the file
  void* buff = nullptr;
  nsPrimitiveHelpers::CreateDataFromPrimitive(mFlavor, aData, &buff, aDataLen);
  if (buff) {
    int32_t written = PR_Write(mCacheFD, buff, aDataLen);
    free(buff);
    if (written) {
      return NS_OK;
    }
  }
  PR_Close(mCacheFD);
  mCacheFD = nullptr;
  return NS_ERROR_FAILURE;
}


//-------------------------------------------------------------------------
nsresult
DataStruct::ReadCache(nsISupports** aData, uint32_t* aDataLen)
{
  if (!mCacheFD) {
    return NS_ERROR_FAILURE;
  }

  PRFileInfo fileInfo;
  if (PR_GetOpenFileInfo(mCacheFD, &fileInfo) != PR_SUCCESS) {
    return NS_ERROR_FAILURE;
  }
  if (PR_Seek64(mCacheFD, 0, PR_SEEK_SET) == -1) {
    return NS_ERROR_FAILURE;
  }
  uint32_t fileSize = fileInfo.size;

  auto data = mozilla::MakeUnique<char[]>(fileSize);
  if (!data) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  uint32_t actual = PR_Read(mCacheFD, data.get(), fileSize);
  if (actual != fileSize) {
    return NS_ERROR_FAILURE;
  }

  nsPrimitiveHelpers::CreatePrimitiveForData(mFlavor, data.get(), fileSize, aData);
  *aDataLen = fileSize;
  return NS_OK;
}


//-------------------------------------------------------------------------
//
// Transferable constructor
//
//-------------------------------------------------------------------------
nsTransferable::nsTransferable()
  : mPrivateData(false)
  , mContentPolicyType(nsIContentPolicy::TYPE_OTHER)
#ifdef DEBUG
  , mInitialized(false)
#endif
{
}

//-------------------------------------------------------------------------
//
// Transferable destructor
//
//-------------------------------------------------------------------------
nsTransferable::~nsTransferable()
{
}


NS_IMETHODIMP
nsTransferable::Init(nsILoadContext* aContext)
{
  MOZ_ASSERT(!mInitialized);

  if (aContext) {
    mPrivateData = aContext->UsePrivateBrowsing();
  }
#ifdef DEBUG
  mInitialized = true;
#endif
  return NS_OK;
}

//
// GetTransferDataFlavors
//
// Returns a copy of the internal list of flavors. This does NOT take into
// account any converter that may be registered. This list consists of
// nsISupportsCString objects so that the flavor list can be accessed from JS.
//
already_AddRefed<nsIMutableArray>
nsTransferable::GetTransferDataFlavors()
{
  MOZ_ASSERT(mInitialized);

  nsCOMPtr<nsIMutableArray> array = nsArray::Create();

  for (size_t i = 0; i < mDataArray.Length(); ++i) {
    DataStruct& data = mDataArray.ElementAt(i);
    nsCOMPtr<nsISupportsCString> flavorWrapper = do_CreateInstance(NS_SUPPORTS_CSTRING_CONTRACTID);
    if ( flavorWrapper ) {
      flavorWrapper->SetData ( data.GetFlavor() );
      nsCOMPtr<nsISupports> genericWrapper ( do_QueryInterface(flavorWrapper) );
      array->AppendElement( genericWrapper );
    }
  }

  return array.forget();
}


//
// GetTransferData
//
// Returns the data of the requested flavor, obtained from either having the data on hand or
// using a converter to get it. The data is wrapped in a nsISupports primitive so that it is
// accessible from JS.
//
NS_IMETHODIMP
nsTransferable::GetTransferData(const char *aFlavor, nsISupports **aData, uint32_t *aDataLen)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(aFlavor && aData && aDataLen);

  nsresult rv = NS_OK;
  nsCOMPtr<nsISupports> savedData;

  // first look and see if the data is present in one of the intrinsic flavors
  for (size_t i = 0; i < mDataArray.Length(); ++i) {
    DataStruct& data = mDataArray.ElementAt(i);
    if ( data.GetFlavor().Equals(aFlavor) ) {
      nsCOMPtr<nsISupports> dataBytes;
      uint32_t len;
      data.GetData(getter_AddRefs(dataBytes), &len);
      if (len == kFlavorHasDataProvider && dataBytes) {
        // do we have a data provider?
        nsCOMPtr<nsIFlavorDataProvider> dataProvider = do_QueryInterface(dataBytes);
        if (dataProvider) {
          rv = dataProvider->GetFlavorData(this, aFlavor,
                                           getter_AddRefs(dataBytes), &len);
          if (NS_FAILED(rv))
            break;    // the provider failed. fall into the converter code below.
        }
      }
      if (dataBytes && len > 0) { // XXXmats why is zero length not ok?
        *aDataLen = len;
        dataBytes.forget(aData);
        return NS_OK;
      }
      savedData = dataBytes;  // return this if format converter fails
      break;
    }
  }

  bool found = false;

  // if not, try using a format converter to get the requested flavor
  if ( mFormatConv ) {
    for (size_t i = 0; i < mDataArray.Length(); ++i) {
      DataStruct& data = mDataArray.ElementAt(i);
      bool canConvert = false;
      mFormatConv->CanConvert(data.GetFlavor().get(), aFlavor, &canConvert);
      if ( canConvert ) {
        nsCOMPtr<nsISupports> dataBytes;
        uint32_t len;
        data.GetData(getter_AddRefs(dataBytes), &len);
        if (len == kFlavorHasDataProvider && dataBytes) {
          // do we have a data provider?
          nsCOMPtr<nsIFlavorDataProvider> dataProvider = do_QueryInterface(dataBytes);
          if (dataProvider) {
            rv = dataProvider->GetFlavorData(this, aFlavor,
                                             getter_AddRefs(dataBytes), &len);
            if (NS_FAILED(rv))
              break;  // give up
          }
        }
        mFormatConv->Convert(data.GetFlavor().get(), dataBytes, len, aFlavor, aData, aDataLen);
        found = true;
        break;
      }
    }
  }

  // for backward compatibility
  if (!found) {
    savedData.forget(aData);
    *aDataLen = 0;
  }

  return found ? NS_OK : NS_ERROR_FAILURE;
}


//
// GetAnyTransferData
//
// Returns the data of the first flavor found. Caller is responsible for deleting the
// flavor string.
//
NS_IMETHODIMP
nsTransferable::GetAnyTransferData(nsACString& aFlavor, nsISupports **aData,
                                   uint32_t *aDataLen)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(aData && aDataLen);

  for (size_t i = 0; i < mDataArray.Length(); ++i) {
    DataStruct& data = mDataArray.ElementAt(i);
    if (data.IsDataAvailable()) {
      aFlavor.Assign(data.GetFlavor());
      data.GetData(aData, aDataLen);
      return NS_OK;
    }
  }

  return NS_ERROR_FAILURE;
}


//
// SetTransferData
//
//
//
NS_IMETHODIMP
nsTransferable::SetTransferData(const char *aFlavor, nsISupports *aData, uint32_t aDataLen)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG(aFlavor);

  // first check our intrinsic flavors to see if one has been registered.
  for (size_t i = 0; i < mDataArray.Length(); ++i) {
    DataStruct& data = mDataArray.ElementAt(i);
    if ( data.GetFlavor().Equals(aFlavor) ) {
      data.SetData ( aData, aDataLen, mPrivateData );
      return NS_OK;
    }
  }

  // if not, try using a format converter to find a flavor to put the data in
  if ( mFormatConv ) {
    for (size_t i = 0; i < mDataArray.Length(); ++i) {
      DataStruct& data = mDataArray.ElementAt(i);
      bool canConvert = false;
      mFormatConv->CanConvert(aFlavor, data.GetFlavor().get(), &canConvert);

      if ( canConvert ) {
        nsCOMPtr<nsISupports> ConvertedData;
        uint32_t ConvertedLen;
        mFormatConv->Convert(aFlavor, aData, aDataLen, data.GetFlavor().get(), getter_AddRefs(ConvertedData), &ConvertedLen);
        data.SetData(ConvertedData, ConvertedLen, mPrivateData);
        return NS_OK;
      }
    }
  }

  // Can't set data neither directly nor through converter. Just add this flavor and try again
  nsresult result = NS_ERROR_FAILURE;
  if ( NS_SUCCEEDED(AddDataFlavor(aFlavor)) )
    result = SetTransferData (aFlavor, aData, aDataLen);

  return result;
}


//
// AddDataFlavor
//
// Adds a data flavor to our list with no data. Error if it already exists.
//
NS_IMETHODIMP
nsTransferable::AddDataFlavor(const char *aDataFlavor)
{
  MOZ_ASSERT(mInitialized);

  if (GetDataForFlavor (mDataArray, aDataFlavor) != mDataArray.NoIndex)
    return NS_ERROR_FAILURE;

  // Create a new "slot" for the data
  mDataArray.AppendElement(DataStruct ( aDataFlavor ));

  return NS_OK;
}


//
// RemoveDataFlavor
//
// Removes a data flavor (and causes the data to be destroyed). Error if
// the requested flavor is not present.
//
NS_IMETHODIMP
nsTransferable::RemoveDataFlavor(const char *aDataFlavor)
{
  MOZ_ASSERT(mInitialized);

  size_t idx = GetDataForFlavor(mDataArray, aDataFlavor);
  if (idx != mDataArray.NoIndex) {
    mDataArray.RemoveElementAt (idx);
    return NS_OK;
  }
  return NS_ERROR_FAILURE;
}


/**
  *
  *
  */
NS_IMETHODIMP
nsTransferable::IsLargeDataSet(bool *_retval)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(_retval);
  *_retval = false;
  return NS_OK;
}


/**
  *
  *
  */
NS_IMETHODIMP nsTransferable::SetConverter(nsIFormatConverter * aConverter)
{
  MOZ_ASSERT(mInitialized);

  mFormatConv = aConverter;
  return NS_OK;
}


/**
  *
  *
  */
NS_IMETHODIMP nsTransferable::GetConverter(nsIFormatConverter * *aConverter)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(aConverter);
  *aConverter = mFormatConv;
  NS_IF_ADDREF(*aConverter);
  return NS_OK;
}


//
// FlavorsTransferableCanImport
//
// Computes a list of flavors that the transferable can accept into it, either through
// intrinsic knowledge or input data converters.
//
NS_IMETHODIMP
nsTransferable::FlavorsTransferableCanImport(nsIArray **_retval)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(_retval);

  // Get the flavor list, and on to the end of it, append the list of flavors we
  // can also get to through a converter. This is so that we can just walk the list
  // in one go, looking for the desired flavor.
  nsCOMPtr<nsIMutableArray> array = GetTransferDataFlavors();
  nsCOMPtr<nsIFormatConverter> converter;
  GetConverter(getter_AddRefs(converter));
  if ( converter ) {
    nsCOMPtr<nsIArray> convertedList;
    converter->GetInputDataFlavors(getter_AddRefs(convertedList));

    if ( convertedList ) {
      uint32_t importListLen;
      convertedList->GetLength(&importListLen);

      for (uint32_t i = 0; i < importListLen; ++i ) {
        nsCOMPtr<nsISupportsCString> flavorWrapper =
            do_QueryElementAt(convertedList, i);
        nsAutoCString flavorStr;
        flavorWrapper->GetData( flavorStr );

        if (GetDataForFlavor (mDataArray, flavorStr.get())
            == mDataArray.NoIndex) // Don't append if already in intrinsic list
          array->AppendElement (flavorWrapper);
      } // foreach flavor that can be converted to
    }
  } // if a converter exists

  array.forget(_retval);
  return NS_OK;
} // FlavorsTransferableCanImport


//
// FlavorsTransferableCanExport
//
// Computes a list of flavors that the transferable can export, either through
// intrinsic knowledge or output data converters.
//
NS_IMETHODIMP
nsTransferable::FlavorsTransferableCanExport(nsIArray **_retval)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(_retval);

  // Get the flavor list, and on to the end of it, append the list of flavors we
  // can also get to through a converter. This is so that we can just walk the list
  // in one go, looking for the desired flavor.
  nsCOMPtr<nsIMutableArray> array = GetTransferDataFlavors();
  nsCOMPtr<nsIFormatConverter> converter;
  GetConverter(getter_AddRefs(converter));
  if ( converter ) {
    nsCOMPtr<nsIArray> convertedList;
    converter->GetOutputDataFlavors(getter_AddRefs(convertedList));

    if ( convertedList ) {
      uint32_t importListLen;
      convertedList->GetLength(&importListLen);

      for ( uint32_t i=0; i < importListLen; ++i ) {
        nsCOMPtr<nsISupportsCString> flavorWrapper =
            do_QueryElementAt(convertedList, i);
        nsAutoCString flavorStr;
        flavorWrapper->GetData( flavorStr );

        if (GetDataForFlavor (mDataArray, flavorStr.get())
            == mDataArray.NoIndex) // Don't append if already in intrinsic list
          array->AppendElement (flavorWrapper);
      } // foreach flavor that can be converted to
    }
  } // if a converter exists

  array.forget(_retval);
  return NS_OK;
} // FlavorsTransferableCanExport

NS_IMETHODIMP
nsTransferable::GetIsPrivateData(bool *aIsPrivateData)
{
  MOZ_ASSERT(mInitialized);

  NS_ENSURE_ARG_POINTER(aIsPrivateData);

  *aIsPrivateData = mPrivateData;

  return NS_OK;
}

NS_IMETHODIMP
nsTransferable::SetIsPrivateData(bool aIsPrivateData)
{
  MOZ_ASSERT(mInitialized);

  mPrivateData = aIsPrivateData;

  return NS_OK;
}

NS_IMETHODIMP
nsTransferable::GetRequestingPrincipal(nsIPrincipal** outRequestingPrincipal)
{
  NS_IF_ADDREF(*outRequestingPrincipal = mRequestingPrincipal);
  return NS_OK;
}

NS_IMETHODIMP
nsTransferable::SetRequestingPrincipal(nsIPrincipal* aRequestingPrincipal)
{
  mRequestingPrincipal = aRequestingPrincipal;
  return NS_OK;
}

NS_IMETHODIMP
nsTransferable::GetContentPolicyType(nsContentPolicyType* outContentPolicyType)
{
  NS_ENSURE_ARG_POINTER(outContentPolicyType);
  *outContentPolicyType = mContentPolicyType;
  return NS_OK;
}

NS_IMETHODIMP
nsTransferable::SetContentPolicyType(nsContentPolicyType aContentPolicyType)
{
  mContentPolicyType = aContentPolicyType;
  return NS_OK;
}