The Tor Browser: widget/xpwidgets/nsTransferable.cpp@ac0c01689b40 (annotated)

widget/xpwidgets/nsTransferable.cpp@ac0c01689b40 (annotated)

widget/xpwidgets/nsTransferable.cpp

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
parent 9: a63d609f5ebe
child 11: deefc01c0e14
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- 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 nsISupportsArrays.
 */
 #include "nsTransferable.h"
 #include "nsString.h"
 #include "nsReadableUtils.h"
 #include "nsTArray.h"
 #include "nsIFormatConverter.h"
 #include "nsIComponentManager.h"
 #include "nsCOMPtr.h"
 #include "nsXPCOM.h"
 #include "nsISupportsPrimitives.h"
 #include "nsMemory.h"
 #include "nsPrimitiveHelpers.h"
 #include "nsXPIDLString.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsDirectoryService.h"
 #include "nsCRT.h"
 #include "nsNetUtil.h"
 #include "nsIOutputStream.h"
 #include "nsIInputStream.h"
 #include "nsIFile.h"
 #include "nsILoadContext.h"
 #include "nsAutoPtr.h"
 NS_IMPL_ISUPPORTS(nsTransferable, nsITransferable)
 uint32_t GetDataForFlavor (const nsTArray<DataStruct>& aArray,
                            const char* aDataFlavor)
 {
   for (uint32_t i = 0 ; i < aArray.Length () ; ++i) {
     if (aArray[i].GetFlavor().Equals (aDataFlavor))
       return i;
   }
   return aArray.NoIndex;
 }
 //-------------------------------------------------------------------------
 DataStruct::~DataStruct()
 {
   if (mCacheFileName) free(mCacheFileName);
 }
 //-------------------------------------------------------------------------
 // The SetData method is overloaded to indicate private browsing mode
 // while achieving some semblance of (private) interface compatibility.
 //-------------------------------------------------------------------------
 void
 DataStruct::SetData ( nsISupports* aData, uint32_t aDataLen, bool aIsPrivBrowsing )
 {
   // 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 && aIsPrivBrowsing == false) {
     // if so, cache it to disk instead of memory
     if ( NS_SUCCEEDED(WriteCache(aData, aDataLen)) )
       return;
     else
       NS_WARNING("Oh no, couldn't write data to the cache file");
   }
   mData    = aData;
   mDataLen = aDataLen;
 }
 //-------------------------------------------------------------------------
 void
 DataStruct::SetData ( nsISupports* aData, uint32_t aDataLen )
 {
   // Now, check to see if we consider the data to be "too large"
   if (aDataLen > kLargeDatasetSize) {
     // if so, cache it to disk instead of memory
     if ( NS_SUCCEEDED(WriteCache(aData, aDataLen)) )
       return;
     else
 			NS_WARNING("Oh no, couldn't write data to the cache file");
   }
   mData    = aData;
   mDataLen = aDataLen;
 }
 //-------------------------------------------------------------------------
 void
 DataStruct::GetData ( nsISupports** aData, uint32_t *aDataLen )
 {
   // check here to see if the data is cached on disk
   if ( !mData && mCacheFileName ) {
     // 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;
       return;
     }
   }
   *aData = mData;
   if ( mData )
     NS_ADDREF(*aData);
   *aDataLen = mDataLen;
 }
 //-------------------------------------------------------------------------
 already_AddRefed<nsIFile>
 DataStruct::GetFileSpec(const char* aFileName)
 {
   nsCOMPtr<nsIFile> cacheFile;
   NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(cacheFile));
   if (!cacheFile)
     return nullptr;
   // if the param aFileName contains a name we should use that
   // because the file probably already exists
   // otherwise create a unique name
   if (!aFileName) {
     cacheFile->AppendNative(NS_LITERAL_CSTRING("clipboardcache"));
     cacheFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
   } else {
     cacheFile->AppendNative(nsDependentCString(aFileName));
   }
   return cacheFile.forget();
 }
 //-------------------------------------------------------------------------
 nsresult
 DataStruct::WriteCache(nsISupports* aData, uint32_t aDataLen)
 {
   // Get a new path and file to the temp directory
   nsCOMPtr<nsIFile> cacheFile = GetFileSpec(mCacheFileName);
   if (cacheFile) {
     // remember the file name
     if (!mCacheFileName) {
       nsXPIDLCString fName;
       cacheFile->GetNativeLeafName(fName);
       mCacheFileName = strdup(fName);
     }
     // write out the contents of the clipboard
     // to the file
     //uint32_t bytes;
     nsCOMPtr<nsIOutputStream> outStr;
     NS_NewLocalFileOutputStream(getter_AddRefs(outStr),
                                 cacheFile);
     if (!outStr) return NS_ERROR_FAILURE;
     void* buff = nullptr;
     nsPrimitiveHelpers::CreateDataFromPrimitive ( mFlavor.get(), aData, &buff, aDataLen );
     if ( buff ) {
       uint32_t ignored;
       outStr->Write(reinterpret_cast<char*>(buff), aDataLen, &ignored);
       nsMemory::Free(buff);
       return NS_OK;
     }
   }
   return NS_ERROR_FAILURE;
 }
 //-------------------------------------------------------------------------
 nsresult
 DataStruct::ReadCache(nsISupports** aData, uint32_t* aDataLen)
 {
   // if we don't have a cache filename we are out of luck
   if (!mCacheFileName)
     return NS_ERROR_FAILURE;
   // get the path and file name
   nsCOMPtr<nsIFile> cacheFile = GetFileSpec(mCacheFileName);
   bool exists;
   if ( cacheFile && NS_SUCCEEDED(cacheFile->Exists(&exists)) && exists ) {
     // get the size of the file
     int64_t fileSize;
     int64_t max32 = 0xFFFFFFFF;
     cacheFile->GetFileSize(&fileSize);
     if (fileSize > max32)
       return NS_ERROR_OUT_OF_MEMORY;
     uint32_t size = uint32_t(fileSize);
     // create new memory for the large clipboard data
     nsAutoArrayPtr<char> data(new char[size]);
     if ( !data )
       return NS_ERROR_OUT_OF_MEMORY;
     // now read it all in
     nsCOMPtr<nsIInputStream> inStr;
     NS_NewLocalFileInputStream( getter_AddRefs(inStr),
                                 cacheFile);
     if (!cacheFile) return NS_ERROR_FAILURE;
     nsresult rv = inStr->Read(data, fileSize, aDataLen);
     // make sure we got all the data ok
     if (NS_SUCCEEDED(rv) && *aDataLen == size) {
       nsPrimitiveHelpers::CreatePrimitiveForData ( mFlavor.get(), data, fileSize, aData );
       return *aData ? NS_OK : NS_ERROR_FAILURE;
     }
     // zero the return params
     *aData    = nullptr;
     *aDataLen = 0;
   }
   return NS_ERROR_FAILURE;
 }
 //-------------------------------------------------------------------------
 //
 // Transferable constructor
 //
 //-------------------------------------------------------------------------
 nsTransferable::nsTransferable()
   : mPrivateData(false)
 #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.
 //
 nsresult
 nsTransferable::GetTransferDataFlavors(nsISupportsArray ** aDataFlavorList)
 {
   MOZ_ASSERT(mInitialized);
   nsresult rv = NS_NewISupportsArray ( aDataFlavorList );
   if (NS_FAILED(rv)) return rv;
   for ( uint32_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) );
       (*aDataFlavorList)->AppendElement( genericWrapper );
     }
   }
   return NS_OK;
 }
 //
 // 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
   uint32_t i;
   for (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 (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(char **aFlavor, nsISupports **aData, uint32_t *aDataLen)
 {
   MOZ_ASSERT(mInitialized);
   NS_ENSURE_ARG_POINTER(aFlavor && aData && aDataLen);
   for ( uint32_t i=0; i < mDataArray.Length(); ++i ) {
     DataStruct& data = mDataArray.ElementAt(i);
     if (data.IsDataAvailable()) {
       *aFlavor = ToNewCString(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.
   uint32_t i = 0;
   bool aIsPrivBrowsing = false;
   for (i = 0; i < mDataArray.Length(); ++i) {
     DataStruct& data = mDataArray.ElementAt(i);
     if ( data.GetFlavor().Equals(aFlavor) ) {
       if ( NS_SUCCEEDED(GetIsPrivateData(&aIsPrivBrowsing)) ) {
         data.SetData ( aData, aDataLen, aIsPrivBrowsing );
         return NS_OK;
       }
       else {                     // call to GetIsPrivateData() failed,
         return NS_ERROR_FAILURE; // we didn't SetData(), generic error
       }
     }
   }
   // if not, try using a format converter to find a flavor to put the data in
   if ( mFormatConv ) {
     for (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);
         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);
   uint32_t idx;
   if ((idx = GetDataForFlavor(mDataArray, aDataFlavor)) != 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(nsISupportsArray **_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.
   GetTransferDataFlavors(_retval);                        // addrefs
   nsCOMPtr<nsIFormatConverter> converter;
   GetConverter(getter_AddRefs(converter));
   if ( converter ) {
     nsCOMPtr<nsISupportsArray> convertedList;
     converter->GetInputDataFlavors(getter_AddRefs(convertedList));
     if ( convertedList ) {
       uint32_t importListLen;
       convertedList->Count(&importListLen);
       for ( uint32_t i=0; i < importListLen; ++i ) {
         nsCOMPtr<nsISupports> genericFlavor;
         convertedList->GetElementAt ( i, getter_AddRefs(genericFlavor) );
         nsCOMPtr<nsISupportsCString> flavorWrapper ( do_QueryInterface (genericFlavor) );
         nsAutoCString flavorStr;
         flavorWrapper->GetData( flavorStr );
         if (GetDataForFlavor (mDataArray, flavorStr.get())
             == mDataArray.NoIndex) // Don't append if already in intrinsic list
           (*_retval)->AppendElement (genericFlavor);
       } // foreach flavor that can be converted to
     }
   } // if a converter exists
   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(nsISupportsArray **_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.
   GetTransferDataFlavors(_retval);  // addrefs
   nsCOMPtr<nsIFormatConverter> converter;
   GetConverter(getter_AddRefs(converter));
   if ( converter ) {
     nsCOMPtr<nsISupportsArray> convertedList;
     converter->GetOutputDataFlavors(getter_AddRefs(convertedList));
     if ( convertedList ) {
       uint32_t importListLen;
       convertedList->Count(&importListLen);
       for ( uint32_t i=0; i < importListLen; ++i ) {
         nsCOMPtr<nsISupports> genericFlavor;
         convertedList->GetElementAt ( i, getter_AddRefs(genericFlavor) );
         nsCOMPtr<nsISupportsCString> flavorWrapper ( do_QueryInterface (genericFlavor) );
         nsAutoCString flavorStr;
         flavorWrapper->GetData( flavorStr );
         if (GetDataForFlavor (mDataArray, flavorStr.get())
             == mDataArray.NoIndex) // Don't append if already in intrinsic list
           (*_retval)->AppendElement (genericFlavor);
       } // foreach flavor that can be converted to
     }
   } // if a converter exists
   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;
 }

The Tor Browser / annotate

widget/xpwidgets/nsTransferable.cpp@ac0c01689b40 (annotated)

widget/xpwidgets/nsTransferable.cpp