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/* -*- Mode: C++; tab-width: 8; 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/. */
/*
* A class that handles loading and evaluation of <script> elements.
*/
#include "ScriptLoadHandler.h"
#include "ScriptLoader.h"
#include "nsContentUtils.h"
#include "mozilla/dom/EncodingUtils.h"
namespace mozilla {
namespace dom {
ScriptLoadHandler::ScriptLoadHandler(ScriptLoader *aScriptLoader,
ScriptLoadRequest *aRequest,
mozilla::dom::SRICheckDataVerifier *aSRIDataVerifier)
: mScriptLoader(aScriptLoader),
mRequest(aRequest),
mSRIDataVerifier(aSRIDataVerifier),
mSRIStatus(NS_OK),
mDecoder(),
mBuffer()
{}
ScriptLoadHandler::~ScriptLoadHandler()
{}
NS_IMPL_ISUPPORTS(ScriptLoadHandler, nsIIncrementalStreamLoaderObserver)
NS_IMETHODIMP
ScriptLoadHandler::OnIncrementalData(nsIIncrementalStreamLoader* aLoader,
nsISupports* aContext,
uint32_t aDataLength,
const uint8_t* aData,
uint32_t *aConsumedLength)
{
if (mRequest->IsCanceled()) {
// If request cancelled, ignore any incoming data.
*aConsumedLength = aDataLength;
return NS_OK;
}
if (!EnsureDecoder(aLoader, aData, aDataLength,
/* aEndOfStream = */ false)) {
return NS_OK;
}
// Below we will/shall consume entire data chunk.
*aConsumedLength = aDataLength;
// Decoder has already been initialized. -- trying to decode all loaded bytes.
nsresult rv = TryDecodeRawData(aData, aDataLength,
/* aEndOfStream = */ false);
NS_ENSURE_SUCCESS(rv, rv);
// If SRI is required for this load, appending new bytes to the hash.
if (mSRIDataVerifier && NS_SUCCEEDED(mSRIStatus)) {
mSRIStatus = mSRIDataVerifier->Update(aDataLength, aData);
}
return rv;
}
nsresult
ScriptLoadHandler::TryDecodeRawData(const uint8_t* aData,
uint32_t aDataLength,
bool aEndOfStream)
{
int32_t srcLen = aDataLength;
const char* src = reinterpret_cast<const char *>(aData);
int32_t dstLen;
nsresult rv =
mDecoder->GetMaxLength(src, srcLen, &dstLen);
NS_ENSURE_SUCCESS(rv, rv);
uint32_t haveRead = mBuffer.length();
CheckedInt<uint32_t> capacity = haveRead;
capacity += dstLen;
if (!capacity.isValid() || !mBuffer.reserve(capacity.value())) {
return NS_ERROR_OUT_OF_MEMORY;
}
rv = mDecoder->Convert(src,
&srcLen,
mBuffer.begin() + haveRead,
&dstLen);
NS_ENSURE_SUCCESS(rv, rv);
haveRead += dstLen;
MOZ_ASSERT(haveRead <= capacity.value(), "mDecoder produced more data than expected");
MOZ_ALWAYS_TRUE(mBuffer.resizeUninitialized(haveRead));
return NS_OK;
}
bool
ScriptLoadHandler::EnsureDecoder(nsIIncrementalStreamLoader *aLoader,
const uint8_t* aData,
uint32_t aDataLength,
bool aEndOfStream)
{
// Check if decoder has already been created.
if (mDecoder) {
return true;
}
nsAutoCString charset;
// JavaScript modules are always UTF-8.
if (mRequest->IsModuleRequest()) {
charset = "UTF-8";
mDecoder = EncodingUtils::DecoderForEncoding(charset);
return true;
}
// Determine if BOM check should be done. This occurs either
// if end-of-stream has been reached, or at least 3 bytes have
// been read from input.
if (!aEndOfStream && (aDataLength < 3)) {
return false;
}
// Do BOM detection.
if (nsContentUtils::CheckForBOM(aData, aDataLength, charset)) {
mDecoder = EncodingUtils::DecoderForEncoding(charset);
return true;
}
// BOM detection failed, check content stream for charset.
nsCOMPtr<nsIRequest> req;
nsresult rv = aLoader->GetRequest(getter_AddRefs(req));
NS_ASSERTION(req, "StreamLoader's request went away prematurely");
NS_ENSURE_SUCCESS(rv, false);
nsCOMPtr<nsIChannel> channel = do_QueryInterface(req);
if (channel &&
NS_SUCCEEDED(channel->GetContentCharset(charset)) &&
EncodingUtils::FindEncodingForLabel(charset, charset)) {
mDecoder = EncodingUtils::DecoderForEncoding(charset);
return true;
}
// Check the hint charset from the script element or preload
// request.
nsAutoString hintCharset;
if (!mRequest->IsPreload()) {
mRequest->mElement->GetScriptCharset(hintCharset);
} else {
nsTArray<ScriptLoader::PreloadInfo>::index_type i =
mScriptLoader->mPreloads.IndexOf(mRequest, 0,
ScriptLoader::PreloadRequestComparator());
NS_ASSERTION(i != mScriptLoader->mPreloads.NoIndex,
"Incorrect preload bookkeeping");
hintCharset = mScriptLoader->mPreloads[i].mCharset;
}
if (EncodingUtils::FindEncodingForLabel(hintCharset, charset)) {
mDecoder = EncodingUtils::DecoderForEncoding(charset);
return true;
}
// Get the charset from the charset of the document.
if (mScriptLoader->mDocument) {
charset = mScriptLoader->mDocument->GetDocumentCharacterSet();
mDecoder = EncodingUtils::DecoderForEncoding(charset);
return true;
}
// Curiously, there are various callers that don't pass aDocument. The
// fallback in the old code was ISO-8859-1, which behaved like
// windows-1252. Saying windows-1252 for clarity and for compliance
// with the Encoding Standard.
charset = "windows-1252";
mDecoder = EncodingUtils::DecoderForEncoding(charset);
return true;
}
NS_IMETHODIMP
ScriptLoadHandler::OnStreamComplete(nsIIncrementalStreamLoader* aLoader,
nsISupports* aContext,
nsresult aStatus,
uint32_t aDataLength,
const uint8_t* aData)
{
if (!mRequest->IsCanceled()) {
DebugOnly<bool> encoderSet =
EnsureDecoder(aLoader, aData, aDataLength, /* aEndOfStream = */ true);
MOZ_ASSERT(encoderSet);
DebugOnly<nsresult> rv = TryDecodeRawData(aData, aDataLength,
/* aEndOfStream = */ true);
// If SRI is required for this load, appending new bytes to the hash.
if (mSRIDataVerifier && NS_SUCCEEDED(mSRIStatus)) {
mSRIStatus = mSRIDataVerifier->Update(aDataLength, aData);
}
}
// we have to mediate and use mRequest.
return mScriptLoader->OnStreamComplete(aLoader, mRequest, aStatus, mSRIStatus,
mBuffer, mSRIDataVerifier);
}
} // dom namespace
} // mozilla namespace
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