Quelle FetchPreloader.cpp Sprache: C

/* -*- 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/. */

#include "FetchPreloader.h"

#include "mozilla/Assertions.h"
#include "mozilla/CORSMode.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/dom/Document.h"
#include "mozilla/LoadInfo.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/ReferrerInfo.h"
#include "nsContentPolicyUtils.h"
#include "nsContentSecurityManager.h"
#include "nsContentUtils.h"
#include "nsIChannel.h"
#include "nsIChildChannel.h"
#include "nsIClassOfService.h"
#include "nsIHttpChannel.h"
#include "nsIHttpChannelInternal.h"
#include "nsISupportsPriority.h"
#include "nsITimedChannel.h"
#include "nsNetUtil.h"
#include "nsStringStream.h"
#include "nsIDocShell.h"

namespace mozilla {

NS_IMPL_ISUPPORTS(FetchPreloader, nsIStreamListener, nsIRequestObserver)

FetchPreloader::FetchPreloader()
    : FetchPreloader(nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD) {}

FetchPreloader::FetchPreloader(nsContentPolicyType aContentPolicyType)
    : mContentPolicyType(aContentPolicyType) {}

nsresult FetchPreloader::OpenChannel(const PreloadHashKey& aKey, nsIURI* aURI,
                                     const CORSMode aCORSMode,
                                     const dom::ReferrerPolicy& aReferrerPolicy,
                                     dom::Document* aDocument,
                                     uint64_t aEarlyHintPreloaderId,
                                     int32_t aSupportsPriorityValue) {
  nsresult rv;
  nsCOMPtr<nsIChannel> channel;

  auto notify = MakeScopeExit([&]() {
    if (NS_FAILED(rv)) {
      // Make sure we notify any <link preload> elements when opening fails
      // because of various technical or security reasons.
      NotifyStart(channel);
      // Using the non-channel overload of this method to make it work even
      // before NotifyOpen has been called on this preload.  We are not
      // switching between channels, so it's safe to do so.
      NotifyStop(rv);
    }
  });

  nsCOMPtr<nsILoadGroup> loadGroup = aDocument->GetDocumentLoadGroup();
  nsCOMPtr<nsPIDOMWindowOuter> window = aDocument->GetWindow();
  nsCOMPtr<nsIInterfaceRequestor> prompter;
  if (window) {
    nsIDocShell* docshell = window->GetDocShell();
    prompter = do_QueryInterface(docshell);
  }

  rv = CreateChannel(getter_AddRefs(channel), aURI, aCORSMode, aReferrerPolicy,
                     aDocument, loadGroup, prompter, aEarlyHintPreloaderId,
                     aSupportsPriorityValue);
  NS_ENSURE_SUCCESS(rv, rv);

  // Doing this now so that we have the channel and tainting set on it properly
  // to notify the proper event (load or error) on the associated preload tags
  // when the CSP check fails.
  rv = CheckContentPolicy(aURI, aDocument);
  if (NS_FAILED(rv)) {
    return rv;
  }

  FetchPreloader::PrioritizeAsPreload(channel);
  AddLoadBackgroundFlag(channel);

  NotifyOpen(aKey, channel, aDocument, true);

  if (aEarlyHintPreloaderId) {
    nsCOMPtr<nsIHttpChannelInternal> channelInternal =
        do_QueryInterface(channel);
    NS_ENSURE_TRUE(channelInternal != nullptr, NS_ERROR_FAILURE);

    rv = channelInternal->SetEarlyHintPreloaderId(aEarlyHintPreloaderId);
    NS_ENSURE_SUCCESS(rv, rv);
  }
  return mAsyncConsumeResult = rv = channel->AsyncOpen(this);
}

nsresult FetchPreloader::CreateChannel(
    nsIChannel** aChannel, nsIURI* aURI, const CORSMode aCORSMode,
    const dom::ReferrerPolicy& aReferrerPolicy, dom::Document* aDocument,
    nsILoadGroup* aLoadGroup, nsIInterfaceRequestor* aCallbacks,
    uint64_t aEarlyHintPreloaderId, int32_t aSupportsPriorityValue) {
  nsresult rv;

  nsSecurityFlags securityFlags =
      nsContentSecurityManager::ComputeSecurityFlags(
          aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
                         CORS_NONE_MAPS_TO_DISABLED_CORS_CHECKS);

  nsCOMPtr<nsIChannel> channel;
  rv = NS_NewChannelWithTriggeringPrincipal(
      getter_AddRefs(channel), aURI, aDocument, aDocument->NodePrincipal(),
      securityFlags, nsIContentPolicy::TYPE_FETCH, nullptr, aLoadGroup,
      aCallbacks);
  if (NS_FAILED(rv)) {
    return rv;
  }

  AdjustPriority(channel, aSupportsPriorityValue);

  if (nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(channel)) {
    nsCOMPtr<nsIReferrerInfo> referrerInfo = new dom::ReferrerInfo(
        aDocument->GetDocumentURIAsReferrer(), aReferrerPolicy);
    rv = httpChannel->SetReferrerInfoWithoutClone(referrerInfo);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
  }

  if (nsCOMPtr<nsITimedChannel> timedChannel = do_QueryInterface(channel)) {
    if (aEarlyHintPreloaderId) {
      timedChannel->SetInitiatorType(u"early-hints"_ns);
    } else {
      timedChannel->SetInitiatorType(u"link"_ns);
    }
  }

  channel.forget(aChannel);
  return NS_OK;
}

// static
void FetchPreloader::AdjustPriority(nsIChannel* aChannel,
                                    int32_t aSupportsPriorityValue) {
  if (nsCOMPtr<nsISupportsPriority> supportsPriority{
          do_QueryInterface(aChannel)}) {
    supportsPriority->SetPriority(aSupportsPriorityValue);
  }
}

nsresult FetchPreloader::CheckContentPolicy(nsIURI* aURI,
                                            dom::Document* aDocument) {
  if (!aDocument) {
    return NS_OK;
  }

  nsCOMPtr<nsILoadInfo> secCheckLoadInfo = new net::LoadInfo(
      aDocument->NodePrincipal(), aDocument->NodePrincipal(), aDocument,
      nsILoadInfo::SEC_ONLY_FOR_EXPLICIT_CONTENTSEC_CHECK, mContentPolicyType);

  int16_t shouldLoad = nsIContentPolicy::ACCEPT;
  nsresult rv = NS_CheckContentLoadPolicy(aURI, secCheckLoadInfo, &shouldLoad,
                                          nsContentUtils::GetContentPolicy());
  if (NS_SUCCEEDED(rv) && NS_CP_ACCEPTED(shouldLoad)) {
    return NS_OK;
  }

  return NS_ERROR_CONTENT_BLOCKED;
}

// PreloaderBase

nsresult FetchPreloader::AsyncConsume(nsIStreamListener* aListener) {
  if (NS_FAILED(mAsyncConsumeResult)) {
    // Already being consumed or failed to open.
    return mAsyncConsumeResult;
  }

  // Prevent duplicate calls.
  mAsyncConsumeResult = NS_ERROR_NOT_AVAILABLE;

  if (!mConsumeListener) {
    // Called before we are getting response from the channel.
    mConsumeListener = aListener;
  } else {
    // Channel already started, push cached calls to this listener.
    // Can't be anything else than the `Cache`, hence a safe static_cast.
    Cache* cache = static_cast<Cache*>(mConsumeListener.get());
    cache->AsyncConsume(aListener);
  }

  return NS_OK;
}

// static
void FetchPreloader::PrioritizeAsPreload(nsIChannel* aChannel) {
  if (nsCOMPtr<nsIClassOfService> cos = do_QueryInterface(aChannel)) {
    cos->AddClassFlags(nsIClassOfService::Unblocked);
  }
}

// nsIRequestObserver + nsIStreamListener

NS_IMETHODIMP FetchPreloader::OnStartRequest(nsIRequest* request) {
  NotifyStart(request);

  if (!mConsumeListener) {
    // AsyncConsume not called yet.
    mConsumeListener = new Cache();
  }

  return mConsumeListener->OnStartRequest(request);
}

NS_IMETHODIMP FetchPreloader::OnDataAvailable(nsIRequest* request,
                                              nsIInputStream* input,
                                              uint64_t offset, uint32_t count) {
  return mConsumeListener->OnDataAvailable(request, input, offset, count);
}

NS_IMETHODIMP FetchPreloader::OnStopRequest(nsIRequest* request,
                                            nsresult status) {
  mConsumeListener->OnStopRequest(request, status);

  // We want 404 or other types of server responses to be treated as 'error'.
  if (nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(request)) {
    uint32_t responseStatus = 0;
    Unused << httpChannel->GetResponseStatus(&responseStatus);
    if (responseStatus / 100 != 2) {
      status = NS_ERROR_FAILURE;
    }
  }

  // Fetch preloader wants to keep the channel around so that consumers like XHR
  // can access it even after the preload is done.
  nsCOMPtr<nsIChannel> channel = mChannel;
  NotifyStop(request, status);
  mChannel.swap(channel);
  return NS_OK;
}

// FetchPreloader::Cache

NS_IMPL_ISUPPORTS(FetchPreloader::Cache, nsIStreamListener, nsIRequestObserver)

NS_IMETHODIMP FetchPreloader::Cache::OnStartRequest(nsIRequest* request) {
  mRequest = request;

  if (mFinalListener) {
    return mFinalListener->OnStartRequest(mRequest);
  }

  mCalls.AppendElement(Call{VariantIndex<0>{}, StartRequest{}});
  return NS_OK;
}

NS_IMETHODIMP FetchPreloader::Cache::OnDataAvailable(nsIRequest* request,
                                                     nsIInputStream* input,
                                                     uint64_t offset,
                                                     uint32_t count) {
  if (mFinalListener) {
    return mFinalListener->OnDataAvailable(mRequest, input, offset, count);
  }

  DataAvailable data;
  if (!data.mData.SetLength(count, fallible)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  uint32_t read;
  nsresult rv = input->Read(data.mData.BeginWriting(), count, &read);
  if (NS_FAILED(rv)) {
    return rv;
  }

  mCalls.AppendElement(Call{VariantIndex<1>{}, std::move(data)});
  return NS_OK;
}

NS_IMETHODIMP FetchPreloader::Cache::OnStopRequest(nsIRequest* request,
                                                   nsresult status) {
  if (mFinalListener) {
    return mFinalListener->OnStopRequest(mRequest, status);
  }

  mCalls.AppendElement(Call{VariantIndex<2>{}, StopRequest{status}});
  return NS_OK;
}

void FetchPreloader::Cache::AsyncConsume(nsIStreamListener* aListener) {
  // Must dispatch for two reasons:
  // 1. This is called directly from FetchLoader::AsyncConsume, which must
  // behave the same way as nsIChannel::AsyncOpen.
  // 2. In case there are already stream listener events scheduled on the main
  // thread we preserve the order - those will still end up in Cache.

  // * The `Cache` object is fully main thread only for now, doesn't support
  // retargeting, but it can be improved to allow it.

  nsCOMPtr<nsIStreamListener> listener(aListener);
  NS_DispatchToMainThread(NewRunnableMethod<nsCOMPtr<nsIStreamListener>>(
      "FetchPreloader::Cache::Consume", this, &FetchPreloader::Cache::Consume,
      listener));
}

void FetchPreloader::Cache::Consume(nsCOMPtr<nsIStreamListener> aListener) {
  MOZ_ASSERT(!mFinalListener, "Duplicate call");

  mFinalListener = std::move(aListener);

  // Status of the channel read after each call.
  nsresult status = NS_OK;
  nsCOMPtr<nsIChannel> channel(do_QueryInterface(mRequest));

  RefPtr<Cache> self(this);
  for (auto& call : mCalls) {
    nsresult rv = call.match(
        [&](const StartRequest& startRequest) mutable {
          return self->mFinalListener->OnStartRequest(self->mRequest);
        },
        [&](const DataAvailable& dataAvailable) mutable {
          if (NS_FAILED(status)) {
            // Channel has been cancelled during this mCalls loop.
            return NS_OK;
          }

          nsCOMPtr<nsIInputStream> input;
          rv = NS_NewCStringInputStream(getter_AddRefs(input),
                                        dataAvailable.mData);
          if (NS_FAILED(rv)) {
            return rv;
          }

          return self->mFinalListener->OnDataAvailable(
              self->mRequest, input, 0, dataAvailable.mData.Length());
        },
        [&](const StopRequest& stopRequest) {
          // First cancellation overrides mStatus in nsHttpChannel.
          nsresult stopStatus =
              NS_FAILED(status) ? status : stopRequest.mStatus;
          self->mFinalListener->OnStopRequest(self->mRequest, stopStatus);
          self->mFinalListener = nullptr;
          self->mRequest = nullptr;
          return NS_OK;
        });

    if (!mRequest) {
      // We are done!
      break;
    }

    bool isCancelled = false;
    Unused << channel->GetCanceled(&isCancelled);
    if (isCancelled) {
      mRequest->GetStatus(&status);
    } else if (NS_FAILED(rv)) {
      status = rv;
      mRequest->Cancel(status);
    }
  }

  mCalls.Clear();
}

}  // namespace mozilla

quality98%

¤ Dauer der Verarbeitung: 0.13 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.