michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsDOMFileReader.h"
michael@0: 
michael@0: #include "nsContentCID.h"
michael@0: #include "nsContentUtils.h"
michael@0: #include "nsDOMClassInfoID.h"
michael@0: #include "nsDOMFile.h"
michael@0: #include "nsError.h"
michael@0: #include "nsIConverterInputStream.h"
michael@0: #include "nsIDocument.h"
michael@0: #include "nsIFile.h"
michael@0: #include "nsIFileStreams.h"
michael@0: #include "nsIInputStream.h"
michael@0: #include "nsIMIMEService.h"
michael@0: #include "nsIUnicodeDecoder.h"
michael@0: #include "nsNetCID.h"
michael@0: #include "nsNetUtil.h"
michael@0: 
michael@0: #include "nsLayoutCID.h"
michael@0: #include "nsXPIDLString.h"
michael@0: #include "nsReadableUtils.h"
michael@0: #include "nsIURI.h"
michael@0: #include "nsStreamUtils.h"
michael@0: #include "nsXPCOM.h"
michael@0: #include "nsIDOMEventListener.h"
michael@0: #include "nsJSEnvironment.h"
michael@0: #include "nsIScriptGlobalObject.h"
michael@0: #include "nsCExternalHandlerService.h"
michael@0: #include "nsIStreamConverterService.h"
michael@0: #include "nsCycleCollectionParticipant.h"
michael@0: #include "nsIScriptObjectPrincipal.h"
michael@0: #include "nsHostObjectProtocolHandler.h"
michael@0: #include "mozilla/Base64.h"
michael@0: #include "mozilla/DOMEventTargetHelper.h"
michael@0: #include "mozilla/Preferences.h"
michael@0: #include "mozilla/dom/EncodingUtils.h"
michael@0: #include "mozilla/dom/FileReaderBinding.h"
michael@0: #include "xpcpublic.h"
michael@0: #include "nsIScriptSecurityManager.h"
michael@0: #include "nsDOMJSUtils.h"
michael@0: 
michael@0: #include "jsfriendapi.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: using namespace mozilla::dom;
michael@0: 
michael@0: #define LOAD_STR "load"
michael@0: #define LOADSTART_STR "loadstart"
michael@0: #define LOADEND_STR "loadend"
michael@0: 
michael@0: NS_IMPL_CYCLE_COLLECTION_CLASS(nsDOMFileReader)
michael@0: 
michael@0: NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsDOMFileReader,
michael@0:                                                   FileIOObject)
michael@0:   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFile)
michael@0:   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPrincipal)
michael@0: NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
michael@0: 
michael@0: NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(nsDOMFileReader,
michael@0:                                                 FileIOObject)
michael@0:   tmp->mResultArrayBuffer = nullptr;
michael@0:   NS_IMPL_CYCLE_COLLECTION_UNLINK(mFile)
michael@0:   NS_IMPL_CYCLE_COLLECTION_UNLINK(mPrincipal)
michael@0: NS_IMPL_CYCLE_COLLECTION_UNLINK_END
michael@0: 
michael@0: 
michael@0: NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(nsDOMFileReader,
michael@0:                                                DOMEventTargetHelper)
michael@0:   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mResultArrayBuffer)
michael@0: NS_IMPL_CYCLE_COLLECTION_TRACE_END
michael@0: 
michael@0: NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(nsDOMFileReader)
michael@0:   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
michael@0:   NS_INTERFACE_MAP_ENTRY(nsIDOMFileReader)
michael@0:   NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
michael@0:   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
michael@0: NS_INTERFACE_MAP_END_INHERITING(FileIOObject)
michael@0: 
michael@0: NS_IMPL_ADDREF_INHERITED(nsDOMFileReader, FileIOObject)
michael@0: NS_IMPL_RELEASE_INHERITED(nsDOMFileReader, FileIOObject)
michael@0: 
michael@0: NS_IMPL_EVENT_HANDLER(nsDOMFileReader, load)
michael@0: NS_IMPL_EVENT_HANDLER(nsDOMFileReader, loadend)
michael@0: NS_IMPL_EVENT_HANDLER(nsDOMFileReader, loadstart)
michael@0: NS_IMPL_FORWARD_EVENT_HANDLER(nsDOMFileReader, abort, FileIOObject)
michael@0: NS_IMPL_FORWARD_EVENT_HANDLER(nsDOMFileReader, progress, FileIOObject)
michael@0: NS_IMPL_FORWARD_EVENT_HANDLER(nsDOMFileReader, error, FileIOObject)
michael@0: 
michael@0: void
michael@0: nsDOMFileReader::RootResultArrayBuffer()
michael@0: {
michael@0:   mozilla::HoldJSObjects(this);
michael@0: }
michael@0: 
michael@0: //nsDOMFileReader constructors/initializers
michael@0: 
michael@0: nsDOMFileReader::nsDOMFileReader()
michael@0:   : mFileData(nullptr),
michael@0:     mDataLen(0), mDataFormat(FILE_AS_BINARY),
michael@0:     mResultArrayBuffer(nullptr)
michael@0: {
michael@0:   SetDOMStringToNull(mResult);
michael@0:   SetIsDOMBinding();
michael@0: }
michael@0: 
michael@0: nsDOMFileReader::~nsDOMFileReader()
michael@0: {
michael@0:   FreeFileData();
michael@0:   mResultArrayBuffer = nullptr;
michael@0:   mozilla::DropJSObjects(this);
michael@0: }
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * This Init method is called from the factory constructor.
michael@0:  */
michael@0: nsresult
michael@0: nsDOMFileReader::Init()
michael@0: {
michael@0:   nsIScriptSecurityManager* secMan = nsContentUtils::GetSecurityManager();
michael@0:   nsCOMPtr<nsIPrincipal> principal;
michael@0:   if (secMan) {
michael@0:     secMan->GetSystemPrincipal(getter_AddRefs(principal));
michael@0:   }
michael@0:   NS_ENSURE_STATE(principal);
michael@0:   mPrincipal.swap(principal);
michael@0: 
michael@0:   // Instead of grabbing some random global from the context stack,
michael@0:   // let's use the default one (junk scope) for now.
michael@0:   // We should move away from this Init...
michael@0:   nsCOMPtr<nsIGlobalObject> global = xpc::GetJunkScopeGlobal();
michael@0:   NS_ENSURE_TRUE(global, NS_ERROR_FAILURE);
michael@0:   BindToOwner(global);
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: /* static */ already_AddRefed<nsDOMFileReader>
michael@0: nsDOMFileReader::Constructor(const GlobalObject& aGlobal, ErrorResult& aRv)
michael@0: {
michael@0:   nsRefPtr<nsDOMFileReader> fileReader = new nsDOMFileReader();
michael@0: 
michael@0:   nsCOMPtr<nsPIDOMWindow> owner = do_QueryInterface(aGlobal.GetAsSupports());
michael@0:   if (!owner) {
michael@0:     NS_WARNING("Unexpected nsIJSNativeInitializer owner");
michael@0:     aRv.Throw(NS_ERROR_FAILURE);
michael@0:     return nullptr;
michael@0:   }
michael@0: 
michael@0:   fileReader->BindToOwner(owner);
michael@0: 
michael@0:   // This object is bound to a |window|,
michael@0:   // so reset the principal.
michael@0:   nsCOMPtr<nsIScriptObjectPrincipal> scriptPrincipal = do_QueryInterface(owner);
michael@0:   if (!scriptPrincipal) {
michael@0:     aRv.Throw(NS_ERROR_FAILURE);
michael@0:     return nullptr;
michael@0:   }
michael@0:   fileReader->mPrincipal = scriptPrincipal->GetPrincipal();
michael@0:   return fileReader.forget();
michael@0: }
michael@0: 
michael@0: // nsIInterfaceRequestor
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::GetInterface(const nsIID & aIID, void **aResult)
michael@0: {
michael@0:   return QueryInterface(aIID, aResult);
michael@0: }
michael@0: 
michael@0: // nsIDOMFileReader
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::GetReadyState(uint16_t *aReadyState)
michael@0: {
michael@0:   *aReadyState = ReadyState();
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: void
michael@0: nsDOMFileReader::GetResult(JSContext* aCx, JS::MutableHandle<JS::Value> aResult,
michael@0:                            ErrorResult& aRv)
michael@0: {
michael@0:   aRv = GetResult(aCx, aResult);
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::GetResult(JSContext* aCx, JS::MutableHandle<JS::Value> aResult)
michael@0: {
michael@0:   JS::Rooted<JS::Value> result(aCx);
michael@0:   if (mDataFormat == FILE_AS_ARRAYBUFFER) {
michael@0:     if (mReadyState == nsIDOMFileReader::DONE && mResultArrayBuffer) {
michael@0:       result.setObject(*mResultArrayBuffer);
michael@0:     } else {
michael@0:       result.setNull();
michael@0:     }
michael@0:     if (!JS_WrapValue(aCx, &result)) {
michael@0:       return NS_ERROR_FAILURE;
michael@0:     }
michael@0:     aResult.set(result);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   nsString tmpResult = mResult;
michael@0:   if (!xpc::StringToJsval(aCx, tmpResult, aResult)) {
michael@0:     return NS_ERROR_FAILURE;
michael@0:   }
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::GetError(nsISupports** aError)
michael@0: {
michael@0:   NS_IF_ADDREF(*aError = GetError());
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::ReadAsArrayBuffer(nsIDOMBlob* aFile, JSContext* aCx)
michael@0: {
michael@0:   NS_ENSURE_TRUE(aFile, NS_ERROR_NULL_POINTER);
michael@0:   ErrorResult rv;
michael@0:   ReadAsArrayBuffer(aCx, aFile, rv);
michael@0:   return rv.ErrorCode();
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::ReadAsBinaryString(nsIDOMBlob* aFile)
michael@0: {
michael@0:   NS_ENSURE_TRUE(aFile, NS_ERROR_NULL_POINTER);
michael@0:   ErrorResult rv;
michael@0:   ReadAsBinaryString(aFile, rv);
michael@0:   return rv.ErrorCode();
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::ReadAsText(nsIDOMBlob* aFile,
michael@0:                             const nsAString &aCharset)
michael@0: {
michael@0:   NS_ENSURE_TRUE(aFile, NS_ERROR_NULL_POINTER);
michael@0:   ErrorResult rv;
michael@0:   ReadAsText(aFile, aCharset, rv);
michael@0:   return rv.ErrorCode();
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::ReadAsDataURL(nsIDOMBlob* aFile)
michael@0: {
michael@0:   NS_ENSURE_TRUE(aFile, NS_ERROR_NULL_POINTER);
michael@0:   ErrorResult rv;
michael@0:   ReadAsDataURL(aFile, rv);
michael@0:   return rv.ErrorCode();
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsDOMFileReader::Abort()
michael@0: {
michael@0:   ErrorResult rv;
michael@0:   FileIOObject::Abort(rv);
michael@0:   return rv.ErrorCode();
michael@0: }
michael@0: 
michael@0: /* virtual */ void
michael@0: nsDOMFileReader::DoAbort(nsAString& aEvent)
michael@0: {
michael@0:   // Revert status and result attributes
michael@0:   SetDOMStringToNull(mResult);
michael@0:   mResultArrayBuffer = nullptr;
michael@0:     
michael@0:   // Non-null channel indicates a read is currently active
michael@0:   if (mChannel) {
michael@0:     // Cancel request requires an error status
michael@0:     mChannel->Cancel(NS_ERROR_FAILURE);
michael@0:     mChannel = nullptr;
michael@0:   }
michael@0:   mFile = nullptr;
michael@0: 
michael@0:   //Clean up memory buffer
michael@0:   FreeFileData();
michael@0: 
michael@0:   // Tell the base class which event to dispatch
michael@0:   aEvent = NS_LITERAL_STRING(LOADEND_STR);
michael@0: }
michael@0: 
michael@0: static
michael@0: NS_METHOD
michael@0: ReadFuncBinaryString(nsIInputStream* in,
michael@0:                      void* closure,
michael@0:                      const char* fromRawSegment,
michael@0:                      uint32_t toOffset,
michael@0:                      uint32_t count,
michael@0:                      uint32_t *writeCount)
michael@0: {
michael@0:   char16_t* dest = static_cast<char16_t*>(closure) + toOffset;
michael@0:   char16_t* end = dest + count;
michael@0:   const unsigned char* source = (const unsigned char*)fromRawSegment;
michael@0:   while (dest != end) {
michael@0:     *dest = *source;
michael@0:     ++dest;
michael@0:     ++source;
michael@0:   }
michael@0:   *writeCount = count;
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsDOMFileReader::DoOnDataAvailable(nsIRequest *aRequest,
michael@0:                                    nsISupports *aContext,
michael@0:                                    nsIInputStream *aInputStream,
michael@0:                                    uint64_t aOffset,
michael@0:                                    uint32_t aCount)
michael@0: {
michael@0:   if (mDataFormat == FILE_AS_BINARY) {
michael@0:     //Continuously update our binary string as data comes in
michael@0:     NS_ASSERTION(mResult.Length() == aOffset,
michael@0:                  "unexpected mResult length");
michael@0:     uint32_t oldLen = mResult.Length();
michael@0:     if (uint64_t(oldLen) + aCount > UINT32_MAX)
michael@0:       return NS_ERROR_OUT_OF_MEMORY;
michael@0: 
michael@0:     char16_t *buf = nullptr;
michael@0:     mResult.GetMutableData(&buf, oldLen + aCount, fallible_t());
michael@0:     NS_ENSURE_TRUE(buf, NS_ERROR_OUT_OF_MEMORY);
michael@0: 
michael@0:     uint32_t bytesRead = 0;
michael@0:     aInputStream->ReadSegments(ReadFuncBinaryString, buf + oldLen, aCount,
michael@0:                                &bytesRead);
michael@0:     NS_ASSERTION(bytesRead == aCount, "failed to read data");
michael@0:   }
michael@0:   else if (mDataFormat == FILE_AS_ARRAYBUFFER) {
michael@0:     uint32_t bytesRead = 0;
michael@0:     aInputStream->Read((char*)JS_GetArrayBufferData(mResultArrayBuffer) + aOffset,
michael@0:                        aCount, &bytesRead);
michael@0:     NS_ASSERTION(bytesRead == aCount, "failed to read data");
michael@0:   }
michael@0:   else {
michael@0:     //Update memory buffer to reflect the contents of the file
michael@0:     if (aOffset + aCount > UINT32_MAX) {
michael@0:       // PR_Realloc doesn't support over 4GB memory size even if 64-bit OS
michael@0:       return NS_ERROR_OUT_OF_MEMORY;
michael@0:     }
michael@0:     mFileData = (char *)moz_realloc(mFileData, aOffset + aCount);
michael@0:     NS_ENSURE_TRUE(mFileData, NS_ERROR_OUT_OF_MEMORY);
michael@0: 
michael@0:     uint32_t bytesRead = 0;
michael@0:     aInputStream->Read(mFileData + aOffset, aCount, &bytesRead);
michael@0:     NS_ASSERTION(bytesRead == aCount, "failed to read data");
michael@0: 
michael@0:     mDataLen += aCount;
michael@0:   }
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsDOMFileReader::DoOnStopRequest(nsIRequest *aRequest,
michael@0:                                  nsISupports *aContext,
michael@0:                                  nsresult aStatus,
michael@0:                                  nsAString& aSuccessEvent,
michael@0:                                  nsAString& aTerminationEvent)
michael@0: {
michael@0:   // Make sure we drop all the objects that could hold files open now.
michael@0:   nsCOMPtr<nsIChannel> channel;
michael@0:   mChannel.swap(channel);
michael@0: 
michael@0:   nsCOMPtr<nsIDOMBlob> file;
michael@0:   mFile.swap(file);
michael@0: 
michael@0:   aSuccessEvent = NS_LITERAL_STRING(LOAD_STR);
michael@0:   aTerminationEvent = NS_LITERAL_STRING(LOADEND_STR);
michael@0: 
michael@0:   // Clear out the data if necessary
michael@0:   if (NS_FAILED(aStatus)) {
michael@0:     FreeFileData();
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   nsresult rv = NS_OK;
michael@0:   switch (mDataFormat) {
michael@0:     case FILE_AS_ARRAYBUFFER:
michael@0:       break; //Already accumulated mResultArrayBuffer
michael@0:     case FILE_AS_BINARY:
michael@0:       break; //Already accumulated mResult
michael@0:     case FILE_AS_TEXT:
michael@0:       if (!mFileData) {
michael@0:         if (mDataLen) {
michael@0:           rv = NS_ERROR_OUT_OF_MEMORY;
michael@0:           break;
michael@0:         }
michael@0:         rv = GetAsText(file, mCharset, "", mDataLen, mResult);
michael@0:         break;
michael@0:       }
michael@0:       rv = GetAsText(file, mCharset, mFileData, mDataLen, mResult);
michael@0:       break;
michael@0:     case FILE_AS_DATAURL:
michael@0:       rv = GetAsDataURL(file, mFileData, mDataLen, mResult);
michael@0:       break;
michael@0:   }
michael@0:   
michael@0:   mResult.SetIsVoid(false);
michael@0: 
michael@0:   FreeFileData();
michael@0: 
michael@0:   return rv;
michael@0: }
michael@0: 
michael@0: // Helper methods
michael@0: 
michael@0: void
michael@0: nsDOMFileReader::ReadFileContent(JSContext* aCx,
michael@0:                                  nsIDOMBlob* aFile,
michael@0:                                  const nsAString &aCharset,
michael@0:                                  eDataFormat aDataFormat,
michael@0:                                  ErrorResult& aRv)
michael@0: {
michael@0:   MOZ_ASSERT(aFile);
michael@0: 
michael@0:   //Implicit abort to clear any other activity going on
michael@0:   Abort();
michael@0:   mError = nullptr;
michael@0:   SetDOMStringToNull(mResult);
michael@0:   mTransferred = 0;
michael@0:   mTotal = 0;
michael@0:   mReadyState = nsIDOMFileReader::EMPTY;
michael@0:   FreeFileData();
michael@0: 
michael@0:   mFile = aFile;
michael@0:   mDataFormat = aDataFormat;
michael@0:   CopyUTF16toUTF8(aCharset, mCharset);
michael@0: 
michael@0:   //Establish a channel with our file
michael@0:   {
michael@0:     // Hold the internal URL alive only as long as necessary
michael@0:     // After the channel is created it will own whatever is backing
michael@0:     // the DOMFile.
michael@0:     nsDOMFileInternalUrlHolder urlHolder(mFile, mPrincipal);
michael@0: 
michael@0:     nsCOMPtr<nsIURI> uri;
michael@0:     aRv = NS_NewURI(getter_AddRefs(uri), urlHolder.mUrl);
michael@0:     NS_ENSURE_SUCCESS_VOID(aRv.ErrorCode());
michael@0: 
michael@0:     nsCOMPtr<nsILoadGroup> loadGroup;
michael@0:     if (HasOrHasHadOwner()) {
michael@0:       if (!GetOwner()) {
michael@0:         aRv.Throw(NS_ERROR_FAILURE);
michael@0:         return;
michael@0:       }
michael@0:       nsIDocument* doc = GetOwner()->GetExtantDoc();
michael@0:       if (doc) {
michael@0:         loadGroup = doc->GetDocumentLoadGroup();
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     aRv = NS_NewChannel(getter_AddRefs(mChannel), uri, nullptr, loadGroup,
michael@0:                         nullptr, nsIRequest::LOAD_BACKGROUND);
michael@0:     NS_ENSURE_SUCCESS_VOID(aRv.ErrorCode());
michael@0:   }
michael@0: 
michael@0:   //Obtain the total size of the file before reading
michael@0:   mTotal = mozilla::dom::kUnknownSize;
michael@0:   mFile->GetSize(&mTotal);
michael@0: 
michael@0:   aRv = mChannel->AsyncOpen(this, nullptr);
michael@0:   NS_ENSURE_SUCCESS_VOID(aRv.ErrorCode());
michael@0: 
michael@0:   //FileReader should be in loading state here
michael@0:   mReadyState = nsIDOMFileReader::LOADING;
michael@0:   DispatchProgressEvent(NS_LITERAL_STRING(LOADSTART_STR));
michael@0: 
michael@0:   if (mDataFormat == FILE_AS_ARRAYBUFFER) {
michael@0:     RootResultArrayBuffer();
michael@0:     mResultArrayBuffer = JS_NewArrayBuffer(aCx, mTotal);
michael@0:     if (!mResultArrayBuffer) {
michael@0:       NS_WARNING("Failed to create JS array buffer");
michael@0:       aRv.Throw(NS_ERROR_FAILURE);
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsDOMFileReader::GetAsText(nsIDOMBlob *aFile,
michael@0:                            const nsACString &aCharset,
michael@0:                            const char *aFileData,
michael@0:                            uint32_t aDataLen,
michael@0:                            nsAString& aResult)
michael@0: {
michael@0:   // The BOM sniffing is baked into the "decode" part of the Encoding
michael@0:   // Standard, which the File API references.
michael@0:   nsAutoCString encoding;
michael@0:   if (!nsContentUtils::CheckForBOM(
michael@0:         reinterpret_cast<const unsigned char *>(aFileData),
michael@0:         aDataLen,
michael@0:         encoding)) {
michael@0:     // BOM sniffing failed. Try the API argument.
michael@0:     if (!EncodingUtils::FindEncodingForLabel(aCharset,
michael@0:                                              encoding)) {
michael@0:       // API argument failed. Try the type property of the blob.
michael@0:       nsAutoString type16;
michael@0:       aFile->GetType(type16);
michael@0:       NS_ConvertUTF16toUTF8 type(type16);
michael@0:       nsAutoCString specifiedCharset;
michael@0:       bool haveCharset;
michael@0:       int32_t charsetStart, charsetEnd;
michael@0:       NS_ExtractCharsetFromContentType(type,
michael@0:                                        specifiedCharset,
michael@0:                                        &haveCharset,
michael@0:                                        &charsetStart,
michael@0:                                        &charsetEnd);
michael@0:       if (!EncodingUtils::FindEncodingForLabel(specifiedCharset, encoding)) {
michael@0:         // Type property failed. Use UTF-8.
michael@0:         encoding.AssignLiteral("UTF-8");
michael@0:       }
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   nsDependentCSubstring data(aFileData, aDataLen);
michael@0:   return nsContentUtils::ConvertStringFromEncoding(encoding, data, aResult);
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsDOMFileReader::GetAsDataURL(nsIDOMBlob *aFile,
michael@0:                               const char *aFileData,
michael@0:                               uint32_t aDataLen,
michael@0:                               nsAString& aResult)
michael@0: {
michael@0:   aResult.AssignLiteral("data:");
michael@0: 
michael@0:   nsresult rv;
michael@0:   nsString contentType;
michael@0:   rv = aFile->GetType(contentType);
michael@0:   if (NS_SUCCEEDED(rv) && !contentType.IsEmpty()) {
michael@0:     aResult.Append(contentType);
michael@0:   } else {
michael@0:     aResult.AppendLiteral("application/octet-stream");
michael@0:   }
michael@0:   aResult.AppendLiteral(";base64,");
michael@0: 
michael@0:   nsCString encodedData;
michael@0:   rv = Base64Encode(Substring(aFileData, aDataLen), encodedData);
michael@0:   NS_ENSURE_SUCCESS(rv, rv);
michael@0: 
michael@0:   if (!AppendASCIItoUTF16(encodedData, aResult, fallible_t())) {
michael@0:     return NS_ERROR_OUT_OF_MEMORY;
michael@0:   }
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: /* virtual */ JSObject*
michael@0: nsDOMFileReader::WrapObject(JSContext* aCx)
michael@0: {
michael@0:   return FileReaderBinding::Wrap(aCx, this);
michael@0: }