1 files changed, 474 insertions, 0 deletions
diff --git a/dom/script/ScriptLoadHandler.cpp b/dom/script/ScriptLoadHandler.cpp
new file mode 100644
index 0000000000..03ff5301c5
--- /dev/null
+++ b/dom/script/ScriptLoadHandler.cpp
@@ -0,0 +1,474 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "ScriptLoadHandler.h"
+
+#include <stdlib.h>
+#include <utility>
+#include "ScriptCompression.h"
+#include "ScriptLoader.h"
+#include "ScriptTrace.h"
+#include "js/Transcoding.h"
+#include "js/loader/ScriptLoadRequest.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/Encoding.h"
+#include "mozilla/Logging.h"
+#include "mozilla/NotNull.h"
+#include "mozilla/PerfStats.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/Utf8.h"
+#include "mozilla/Vector.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/SRICheck.h"
+#include "mozilla/dom/ScriptDecoding.h"
+#include "nsCOMPtr.h"
+#include "nsContentUtils.h"
+#include "nsDebug.h"
+#include "nsICacheInfoChannel.h"
+#include "nsIChannel.h"
+#include "nsIHttpChannel.h"
+#include "nsIRequest.h"
+#include "nsIScriptElement.h"
+#include "nsIURI.h"
+#include "nsJSUtils.h"
+#include "nsMimeTypes.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "zlib.h"
+
+namespace mozilla::dom {
+
+#undef LOG
+#define LOG(args) \
+  MOZ_LOG(ScriptLoader::gScriptLoaderLog, mozilla::LogLevel::Debug, args)
+
+#define LOG_ENABLED() \
+  MOZ_LOG_TEST(ScriptLoader::gScriptLoaderLog, mozilla::LogLevel::Debug)
+
+ScriptDecoder::ScriptDecoder(const Encoding* aEncoding,
+                             ScriptDecoder::BOMHandling handleBOM) {
+  if (handleBOM == BOMHandling::Ignore) {
+    mDecoder = aEncoding->NewDecoderWithoutBOMHandling();
+  } else {
+    mDecoder = aEncoding->NewDecoderWithBOMRemoval();
+  }
+  MOZ_ASSERT(mDecoder);
+}
+
+template <typename Unit>
+nsresult ScriptDecoder::DecodeRawDataHelper(
+    JS::loader::ScriptLoadRequest* aRequest, const uint8_t* aData,
+    uint32_t aDataLength, bool aEndOfStream) {
+  CheckedInt<size_t> needed =
+      ScriptDecoding<Unit>::MaxBufferLength(mDecoder, aDataLength);
+  if (!needed.isValid()) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // Reference to the script source buffer which we will update.
+  JS::loader::ScriptLoadRequest::ScriptTextBuffer<Unit>& scriptText =
+      aRequest->ScriptText<Unit>();
+
+  uint32_t haveRead = scriptText.length();
+
+  CheckedInt<uint32_t> capacity = haveRead;
+  capacity += needed.value();
+
+  if (!capacity.isValid() || !scriptText.resize(capacity.value())) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  size_t written = ScriptDecoding<Unit>::DecodeInto(
+      mDecoder, Span(aData, aDataLength),
+      Span(scriptText.begin() + haveRead, needed.value()), aEndOfStream);
+  MOZ_ASSERT(written <= needed.value());
+
+  haveRead += written;
+  MOZ_ASSERT(haveRead <= capacity.value(),
+             "mDecoder produced more data than expected");
+  MOZ_ALWAYS_TRUE(scriptText.resize(haveRead));
+  aRequest->mScriptTextLength = scriptText.length();
+
+  return NS_OK;
+}
+
+nsresult ScriptDecoder::DecodeRawData(JS::loader::ScriptLoadRequest* aRequest,
+                                      const uint8_t* aData,
+                                      uint32_t aDataLength, bool aEndOfStream) {
+  if (aRequest->IsUTF16Text()) {
+    return DecodeRawDataHelper<char16_t>(aRequest, aData, aDataLength,
+                                         aEndOfStream);
+  }
+
+  return DecodeRawDataHelper<Utf8Unit>(aRequest, aData, aDataLength,
+                                       aEndOfStream);
+}
+
+ScriptLoadHandler::ScriptLoadHandler(
+    ScriptLoader* aScriptLoader, JS::loader::ScriptLoadRequest* aRequest,
+    UniquePtr<SRICheckDataVerifier>&& aSRIDataVerifier)
+    : mScriptLoader(aScriptLoader),
+      mRequest(aRequest),
+      mSRIDataVerifier(std::move(aSRIDataVerifier)),
+      mSRIStatus(NS_OK) {
+  MOZ_ASSERT(aRequest->IsUnknownDataType());
+  MOZ_ASSERT(aRequest->IsFetching());
+}
+
+ScriptLoadHandler::~ScriptLoadHandler() = default;
+
+NS_IMPL_ISUPPORTS(ScriptLoadHandler, nsIIncrementalStreamLoaderObserver)
+
+NS_IMETHODIMP
+ScriptLoadHandler::OnIncrementalData(nsIIncrementalStreamLoader* aLoader,
+                                     nsISupports* aContext,
+                                     uint32_t aDataLength, const uint8_t* aData,
+                                     uint32_t* aConsumedLength) {
+  nsCOMPtr<nsIRequest> channelRequest;
+  aLoader->GetRequest(getter_AddRefs(channelRequest));
+
+  auto firstTime = !mPreloadStartNotified;
+  if (!mPreloadStartNotified) {
+    mPreloadStartNotified = true;
+    mRequest->GetScriptLoadContext()->NotifyStart(channelRequest);
+  }
+
+  if (mRequest->IsCanceled()) {
+    // If request cancelled, ignore any incoming data.
+    *aConsumedLength = aDataLength;
+    return NS_OK;
+  }
+
+  nsresult rv = NS_OK;
+  if (mRequest->IsUnknownDataType()) {
+    rv = EnsureKnownDataType(aLoader);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mRequest->IsBytecode() && firstTime) {
+    PerfStats::RecordMeasurementStart(PerfStats::Metric::JSBC_IO_Read);
+  }
+
+  if (mRequest->IsTextSource()) {
+    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.
+    rv = mDecoder->DecodeRawData(mRequest, 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);
+    }
+  } else {
+    MOZ_ASSERT(mRequest->IsBytecode());
+    if (!mRequest->mScriptBytecode.append(aData, aDataLength)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    *aConsumedLength = aDataLength;
+    uint32_t sriLength = 0;
+    rv = MaybeDecodeSRI(&sriLength);
+    if (NS_FAILED(rv)) {
+      return channelRequest->Cancel(mScriptLoader->RestartLoad(mRequest));
+    }
+    if (sriLength) {
+      mRequest->mBytecodeOffset = JS::AlignTranscodingBytecodeOffset(sriLength);
+    }
+  }
+
+  return rv;
+}
+
+bool ScriptLoadHandler::TrySetDecoder(nsIIncrementalStreamLoader* aLoader,
+                                      const uint8_t* aData,
+                                      uint32_t aDataLength, bool aEndOfStream) {
+  MOZ_ASSERT(mDecoder == nullptr,
+             "can't have a decoder already if we're trying to set one");
+
+  // JavaScript modules are always UTF-8.
+  if (mRequest->IsModuleRequest()) {
+    mDecoder = MakeUnique<ScriptDecoder>(UTF_8_ENCODING,
+                                         ScriptDecoder::BOMHandling::Remove);
+    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.
+  const Encoding* encoding;
+  std::tie(encoding, std::ignore) = Encoding::ForBOM(Span(aData, aDataLength));
+  if (encoding) {
+    mDecoder =
+        MakeUnique<ScriptDecoder>(encoding, ScriptDecoder::BOMHandling::Remove);
+    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) {
+    nsAutoCString label;
+    if (NS_SUCCEEDED(channel->GetContentCharset(label)) &&
+        (encoding = Encoding::ForLabel(label))) {
+      mDecoder = MakeUnique<ScriptDecoder>(encoding,
+                                           ScriptDecoder::BOMHandling::Ignore);
+      return true;
+    }
+  }
+
+  // Check the hint charset from the script element or preload
+  // request.
+  nsAutoString hintCharset;
+  if (!mRequest->GetScriptLoadContext()->IsPreload()) {
+    mRequest->GetScriptLoadContext()->GetScriptElement()->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 ((encoding = Encoding::ForLabel(hintCharset))) {
+    mDecoder =
+        MakeUnique<ScriptDecoder>(encoding, ScriptDecoder::BOMHandling::Ignore);
+    return true;
+  }
+
+  // Get the charset from the charset of the document.
+  if (mScriptLoader->mDocument) {
+    encoding = mScriptLoader->mDocument->GetDocumentCharacterSet();
+    mDecoder =
+        MakeUnique<ScriptDecoder>(encoding, ScriptDecoder::BOMHandling::Ignore);
+    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.
+  mDecoder = MakeUnique<ScriptDecoder>(WINDOWS_1252_ENCODING,
+                                       ScriptDecoder::BOMHandling::Ignore);
+  return true;
+}
+
+nsresult ScriptLoadHandler::MaybeDecodeSRI(uint32_t* sriLength) {
+  *sriLength = 0;
+
+  if (!mSRIDataVerifier || mSRIDataVerifier->IsComplete() ||
+      NS_FAILED(mSRIStatus)) {
+    return NS_OK;
+  }
+
+  // Skip until the content is large enough to be decoded.
+  if (mRequest->mScriptBytecode.length() <=
+      mSRIDataVerifier->DataSummaryLength()) {
+    return NS_OK;
+  }
+
+  mSRIStatus = mSRIDataVerifier->ImportDataSummary(
+      mRequest->mScriptBytecode.length(), mRequest->mScriptBytecode.begin());
+
+  if (NS_FAILED(mSRIStatus)) {
+    // We are unable to decode the hash contained in the alternate data which
+    // contains the bytecode, or it does not use the same algorithm.
+    LOG(
+        ("ScriptLoadHandler::MaybeDecodeSRI, failed to decode SRI, restart "
+         "request"));
+    return mSRIStatus;
+  }
+
+  *sriLength = mSRIDataVerifier->DataSummaryLength();
+  MOZ_ASSERT(*sriLength > 0);
+  return NS_OK;
+}
+
+nsresult ScriptLoadHandler::EnsureKnownDataType(
+    nsIIncrementalStreamLoader* aLoader) {
+  MOZ_ASSERT(mRequest->IsUnknownDataType());
+  MOZ_ASSERT(mRequest->IsFetching());
+
+  nsCOMPtr<nsIRequest> req;
+  nsresult rv = aLoader->GetRequest(getter_AddRefs(req));
+  MOZ_ASSERT(req, "StreamLoader's request went away prematurely");
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mRequest->mFetchSourceOnly) {
+    mRequest->SetTextSource();
+    TRACE_FOR_TEST(mRequest->GetScriptLoadContext()->GetScriptElement(),
+                   "scriptloader_load_source");
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsICacheInfoChannel> cic(do_QueryInterface(req));
+  if (cic) {
+    nsAutoCString altDataType;
+    cic->GetAlternativeDataType(altDataType);
+    if (altDataType.Equals(ScriptLoader::BytecodeMimeTypeFor(mRequest))) {
+      mRequest->SetBytecode();
+      TRACE_FOR_TEST(mRequest->GetScriptLoadContext()->GetScriptElement(),
+                     "scriptloader_load_bytecode");
+      return NS_OK;
+    }
+    MOZ_ASSERT(altDataType.IsEmpty());
+  }
+
+  mRequest->SetTextSource();
+  TRACE_FOR_TEST(mRequest->GetScriptLoadContext()->GetScriptElement(),
+                 "scriptloader_load_source");
+
+  MOZ_ASSERT(!mRequest->IsUnknownDataType());
+  MOZ_ASSERT(mRequest->IsFetching());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ScriptLoadHandler::OnStreamComplete(nsIIncrementalStreamLoader* aLoader,
+                                    nsISupports* aContext, nsresult aStatus,
+                                    uint32_t aDataLength,
+                                    const uint8_t* aData) {
+  nsresult rv = NS_OK;
+  if (LOG_ENABLED()) {
+    nsAutoCString url;
+    mRequest->mURI->GetAsciiSpec(url);
+    LOG(("ScriptLoadRequest (%p): Stream complete (url = %s)", mRequest.get(),
+         url.get()));
+  }
+
+  nsCOMPtr<nsIRequest> channelRequest;
+  aLoader->GetRequest(getter_AddRefs(channelRequest));
+
+  auto firstMessage = !mPreloadStartNotified;
+  if (!mPreloadStartNotified) {
+    mPreloadStartNotified = true;
+    mRequest->GetScriptLoadContext()->NotifyStart(channelRequest);
+  }
+
+  auto notifyStop = MakeScopeExit([&] {
+    mRequest->GetScriptLoadContext()->NotifyStop(channelRequest, rv);
+  });
+
+  if (!mRequest->IsCanceled()) {
+    if (mRequest->IsUnknownDataType()) {
+      rv = EnsureKnownDataType(aLoader);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    if (mRequest->IsBytecode() && !firstMessage) {
+      // if firstMessage, then entire stream is in aData, and PerfStats would
+      // measure 0 time
+      PerfStats::RecordMeasurementEnd(PerfStats::Metric::JSBC_IO_Read);
+    }
+
+    if (mRequest->IsTextSource()) {
+      DebugOnly<bool> encoderSet =
+          EnsureDecoder(aLoader, aData, aDataLength, /* aEndOfStream = */ true);
+      MOZ_ASSERT(encoderSet);
+      rv = mDecoder->DecodeRawData(mRequest, aData, aDataLength,
+                                   /* aEndOfStream = */ true);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      LOG(("ScriptLoadRequest (%p): Source length in code units = %u",
+           mRequest.get(), unsigned(mRequest->ScriptTextLength())));
+
+      // If SRI is required for this load, appending new bytes to the hash.
+      if (mSRIDataVerifier && NS_SUCCEEDED(mSRIStatus)) {
+        mSRIStatus = mSRIDataVerifier->Update(aDataLength, aData);
+      }
+    } else {
+      MOZ_ASSERT(mRequest->IsBytecode());
+      if (!mRequest->mScriptBytecode.append(aData, aDataLength)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+
+      LOG(("ScriptLoadRequest (%p): Bytecode length = %u", mRequest.get(),
+           unsigned(mRequest->mScriptBytecode.length())));
+
+      // If we abort while decoding the SRI, we fallback on explictly requesting
+      // the source. Thus, we should not continue in
+      // ScriptLoader::OnStreamComplete, which removes the request from the
+      // waiting lists.
+      //
+      // We calculate the SRI length below.
+      uint32_t unused;
+      rv = MaybeDecodeSRI(&unused);
+      if (NS_FAILED(rv)) {
+        return channelRequest->Cancel(mScriptLoader->RestartLoad(mRequest));
+      }
+
+      // The bytecode cache always starts with the SRI hash, thus even if there
+      // is no SRI data verifier instance, we still want to skip the hash.
+      uint32_t sriLength;
+      rv = SRICheckDataVerifier::DataSummaryLength(
+          mRequest->mScriptBytecode.length(), mRequest->mScriptBytecode.begin(),
+          &sriLength);
+      if (NS_FAILED(rv)) {
+        return channelRequest->Cancel(mScriptLoader->RestartLoad(mRequest));
+      }
+
+      mRequest->mBytecodeOffset = JS::AlignTranscodingBytecodeOffset(sriLength);
+
+      Vector<uint8_t> compressedBytecode;
+      // mRequest has the compressed bytecode, but will be filled with the
+      // uncompressed bytecode
+      compressedBytecode.swap(mRequest->mScriptBytecode);
+      if (!JS::loader::ScriptBytecodeDecompress(compressedBytecode,
+                                                mRequest->mBytecodeOffset,
+                                                mRequest->mScriptBytecode)) {
+        return NS_ERROR_UNEXPECTED;
+      }
+    }
+  }
+
+  // Everything went well, keep the CacheInfoChannel alive such that we can
+  // later save the bytecode on the cache entry.
+  if (NS_SUCCEEDED(rv) && mRequest->IsSource() &&
+      StaticPrefs::dom_script_loader_bytecode_cache_enabled()) {
+    mRequest->mCacheInfo = do_QueryInterface(channelRequest);
+    LOG(("ScriptLoadRequest (%p): nsICacheInfoChannel = %p", mRequest.get(),
+         mRequest->mCacheInfo.get()));
+  }
+
+  // we have to mediate and use mRequest.
+  rv = mScriptLoader->OnStreamComplete(aLoader, mRequest, aStatus, mSRIStatus,
+                                       mSRIDataVerifier.get());
+
+  // In case of failure, clear the mCacheInfoChannel to avoid keeping it alive.
+  if (NS_FAILED(rv)) {
+    mRequest->mCacheInfo = nullptr;
+  }
+
+  return rv;
+}
+
+#undef LOG_ENABLED
+#undef LOG
+
+}  // namespace mozilla::dom