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 "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 "nsILoadContext.h"
#include "nsXULAppAPI.h"
#include "mozilla/UniquePtr.h"

using namespace mozilla;

NS_IMPL_ISUPPORTS(nsTransferable, nsITransferable)

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

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

//-------------------------------------------------------------------------

void DataStruct::SetData(nsISupports* aData, 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.
  // File IO is not allowed in content processes.
  if (!aIsPrivateData && XRE_IsParentProcess()) {
    void* data = nullptr;
    uint32_t dataLen = 0;
    nsPrimitiveHelpers::CreateDataFromPrimitive(mFlavor, aData, &data,
                                                &dataLen);

    if (dataLen > kLargeDatasetSize) {
      // Too large, cache it to disk instead of memory.
      if (NS_SUCCEEDED(WriteCache(data, dataLen))) {
        free(data);
        // Clear previously set small data.
        mData = nullptr;
        return;
      }

      NS_WARNING("Oh no, couldn't write data to the cache file");
    }

    free(data);
  }

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

  mData = aData;
}

//-------------------------------------------------------------------------
void DataStruct::GetData(nsISupports** aData) {
  // 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))) {
      return;
    }

    // oh shit, something went horribly wrong here.
    NS_WARNING("Oh no, couldn't read data in from the cache file");
    *aData = nullptr;
    PR_Close(mCacheFD);
    mCacheFD = nullptr;
    return;
  }

  nsCOMPtr<nsISupports> data = mData;
  data.forget(aData);
}

//-------------------------------------------------------------------------
nsresult DataStruct::WriteCache(void* aData, uint32_t aDataLen) {
  MOZ_ASSERT(aData && aDataLen);
  MOZ_ASSERT(aDataLen <= uint32_t(std::numeric_limits<int32_t>::max()),
             "too large size for PR_Write");

  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.
  int32_t written = PR_Write(mCacheFD, aData, aDataLen);
  if (written == int32_t(aDataLen)) {
    return NS_OK;
  }

  PR_Close(mCacheFD);
  mCacheFD = nullptr;
  return NS_ERROR_FAILURE;
}

//-------------------------------------------------------------------------
nsresult DataStruct::ReadCache(nsISupports** aData) {
  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 = 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);
  return NS_OK;
}

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

//-------------------------------------------------------------------------
//
// Transferable destructor
//
//-------------------------------------------------------------------------
nsTransferable::~nsTransferable() = default;

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.
//
void nsTransferable::GetTransferDataFlavors(nsTArray<nsCString>& aFlavors) {
  MOZ_ASSERT(mInitialized);

  for (size_t i = 0; i < mDataArray.Length(); ++i) {
    DataStruct& data = mDataArray.ElementAt(i);
    aFlavors.AppendElement(data.GetFlavor());
  }
}

Maybe<size_t> nsTransferable::FindDataFlavor(const char* aFlavor) {
  nsDependentCString flavor(aFlavor);

  for (size_t i = 0; i < mDataArray.Length(); ++i) {
    if (mDataArray[i].GetFlavor().Equals(flavor)) {
      return Some(i);
    }
  }

  return Nothing();
}

//
// 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) {
  MOZ_ASSERT(mInitialized);

  *aData = nullptr;

  nsresult rv = NS_OK;

  // First look and see if the data is present in one of the intrinsic flavors.
  if (Maybe<size_t> index = FindDataFlavor(aFlavor)) {
    nsCOMPtr<nsISupports> dataBytes;
    mDataArray[index.value()].GetData(getter_AddRefs(dataBytes));

    // Do we have a (lazy) data provider?
    if (nsCOMPtr<nsIFlavorDataProvider> dataProvider =
            do_QueryInterface(dataBytes)) {
      rv =
          dataProvider->GetFlavorData(this, aFlavor, getter_AddRefs(dataBytes));
      if (NS_FAILED(rv)) {
        dataBytes = nullptr;
        // The provider failed, fall into the converter code below.
      }
    }

    if (dataBytes) {
      dataBytes.forget(aData);
      return NS_OK;
    }

    // Empty data
  }

  // 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;
        data.GetData(getter_AddRefs(dataBytes));

        // Do we have a (lazy) data provider?
        if (nsCOMPtr<nsIFlavorDataProvider> dataProvider =
                do_QueryInterface(dataBytes)) {
          rv = dataProvider->GetFlavorData(this, aFlavor,
                                           getter_AddRefs(dataBytes));
          if (NS_FAILED(rv)) {
            // Give up.
            return rv;
          }
        }

        return mFormatConv->Convert(data.GetFlavor().get(), dataBytes, aFlavor,
                                    aData);
      }
    }
  }

  return 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) {
  MOZ_ASSERT(mInitialized);

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

  return NS_ERROR_FAILURE;
}

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

  // first check our intrinsic flavors to see if one has been registered.
  if (Maybe<size_t> index = FindDataFlavor(aFlavor)) {
    DataStruct& data = mDataArray.ElementAt(index.value());
    data.SetData(aData, 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;
        mFormatConv->Convert(aFlavor, aData, data.GetFlavor().get(),
                             getter_AddRefs(ConvertedData));
        data.SetData(ConvertedData, mPrivateData);
        return NS_OK;
      }
    }
  }

  // Can't set data neither directly nor through converter. Just add this flavor
  // and try again
  if (NS_SUCCEEDED(AddDataFlavor(aFlavor))) {
    return SetTransferData(aFlavor, aData);
  }

  return NS_ERROR_FAILURE;
}

//
// 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 (FindDataFlavor(aDataFlavor).isSome()) {
    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);

  if (Maybe<size_t> index = FindDataFlavor(aDataFlavor)) {
    mDataArray.RemoveElementAt(index.value());
    return NS_OK;
  }

  return NS_ERROR_FAILURE;
}

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

  mFormatConv = aConverter;
  return NS_OK;
}

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

  nsCOMPtr<nsIFormatConverter> converter = mFormatConv;
  converter.forget(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(nsTArray<nsCString>& aFlavors) {
  MOZ_ASSERT(mInitialized);

  // 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.
  GetTransferDataFlavors(aFlavors);

  if (mFormatConv) {
    nsTArray<nsCString> convertedList;
    mFormatConv->GetInputDataFlavors(convertedList);

    for (uint32_t i = 0; i < convertedList.Length(); ++i) {
      nsCString& flavorStr = convertedList[i];

      // Don't append if already in intrinsic list
      if (!aFlavors.Contains(flavorStr)) {
        aFlavors.AppendElement(flavorStr);
      }
    }
  }

  return NS_OK;
}

//
// FlavorsTransferableCanExport
//
// Computes a list of flavors that the transferable can export, either through
// intrinsic knowledge or output data converters.
//
NS_IMETHODIMP
nsTransferable::FlavorsTransferableCanExport(nsTArray<nsCString>& aFlavors) {
  MOZ_ASSERT(mInitialized);

  // 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.
  GetTransferDataFlavors(aFlavors);

  if (mFormatConv) {
    nsTArray<nsCString> convertedList;
    mFormatConv->GetOutputDataFlavors(convertedList);

    for (uint32_t i = 0; i < convertedList.Length(); ++i) {
      nsCString& flavorStr = convertedList[i];

      // Don't append if already in intrinsic list
      if (!aFlavors.Contains(flavorStr)) {
        aFlavors.AppendElement(flavorStr);
      }
    }
  }

  return NS_OK;
}

bool nsTransferable::GetIsPrivateData() {
  MOZ_ASSERT(mInitialized);

  return mPrivateData;
}

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

  mPrivateData = aIsPrivateData;
}

nsIPrincipal* nsTransferable::GetRequestingPrincipal() {
  MOZ_ASSERT(mInitialized);

  return mRequestingPrincipal;
}

void nsTransferable::SetRequestingPrincipal(
    nsIPrincipal* aRequestingPrincipal) {
  MOZ_ASSERT(mInitialized);

  mRequestingPrincipal = aRequestingPrincipal;
}

nsContentPolicyType nsTransferable::GetContentPolicyType() {
  MOZ_ASSERT(mInitialized);

  return mContentPolicyType;
}

void nsTransferable::SetContentPolicyType(
    nsContentPolicyType aContentPolicyType) {
  MOZ_ASSERT(mInitialized);

  mContentPolicyType = aContentPolicyType;
}