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/* 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
#include "PreloaderBase.h"
#include "mozilla/dom/Document.h"
#include "mozilla/Telemetry.h"
#include "nsContentUtils.h"
#include "nsIAsyncVerifyRedirectCallback.h"
#include "nsIHttpChannel.h"
#include "nsILoadGroup.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsIRedirectResultListener.h"
#include "nsNetUtil.h"
// Change this if we want to cancel and remove the associated preload on removal
// of all <link rel=preload> tags from the tree.
constexpr static bool kCancelAndRemovePreloadOnZeroReferences = false;
namespace mozilla {
PreloaderBase::UsageTimer::UsageTimer(PreloaderBase* aPreload,
dom::Document* aDocument)
: mDocument(aDocument), mPreload(aPreload) {}
class PreloaderBase::RedirectSink final : public nsIInterfaceRequestor,
public nsIChannelEventSink,
public nsIRedirectResultListener {
RedirectSink() = delete;
virtual ~RedirectSink();
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIINTERFACEREQUESTOR
NS_DECL_NSICHANNELEVENTSINK
NS_DECL_NSIREDIRECTRESULTLISTENER
RedirectSink(PreloaderBase* aPreloader, nsIInterfaceRequestor* aCallbacks);
private:
MainThreadWeakPtr<PreloaderBase> mPreloader;
nsCOMPtr<nsIInterfaceRequestor> mCallbacks;
nsCOMPtr<nsIChannel> mRedirectChannel;
};
PreloaderBase::RedirectSink::RedirectSink(PreloaderBase* aPreloader,
nsIInterfaceRequestor* aCallbacks)
: mPreloader(aPreloader), mCallbacks(aCallbacks) {}
PreloaderBase::RedirectSink::~RedirectSink() = default;
NS_IMPL_ISUPPORTS(PreloaderBase::RedirectSink, nsIInterfaceRequestor,
nsIChannelEventSink, nsIRedirectResultListener)
NS_IMETHODIMP PreloaderBase::RedirectSink::AsyncOnChannelRedirect(
nsIChannel* aOldChannel, nsIChannel* aNewChannel, uint32_t aFlags,
nsIAsyncVerifyRedirectCallback* aCallback) {
MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
mRedirectChannel = aNewChannel;
// Deliberately adding this before confirmation.
nsCOMPtr<nsIURI> uri;
aNewChannel->GetOriginalURI(getter_AddRefs(uri));
if (mPreloader) {
mPreloader->mRedirectRecords.AppendElement(
RedirectRecord(aFlags, uri.forget()));
}
if (mCallbacks) {
nsCOMPtr<nsIChannelEventSink> sink(do_GetInterface(mCallbacks));
if (sink) {
return sink->AsyncOnChannelRedirect(aOldChannel, aNewChannel, aFlags,
aCallback);
}
}
aCallback->OnRedirectVerifyCallback(NS_OK);
return NS_OK;
}
NS_IMETHODIMP PreloaderBase::RedirectSink::OnRedirectResult(nsresult status) {
if (NS_SUCCEEDED(status) && mRedirectChannel) {
mPreloader->mChannel = std::move(mRedirectChannel);
} else {
mRedirectChannel = nullptr;
}
if (mCallbacks) {
nsCOMPtr<nsIRedirectResultListener> sink(do_GetInterface(mCallbacks));
if (sink) {
return sink->OnRedirectResult(status);
}
}
return NS_OK;
}
NS_IMETHODIMP PreloaderBase::RedirectSink::GetInterface(const nsIID& aIID,
void** aResult) {
NS_ENSURE_ARG_POINTER(aResult);
if (aIID.Equals(NS_GET_IID(nsIChannelEventSink)) ||
aIID.Equals(NS_GET_IID(nsIRedirectResultListener))) {
return QueryInterface(aIID, aResult);
}
if (mCallbacks) {
return mCallbacks->GetInterface(aIID, aResult);
}
*aResult = nullptr;
return NS_ERROR_NO_INTERFACE;
}
PreloaderBase::~PreloaderBase() { MOZ_ASSERT(NS_IsMainThread()); }
// static
void PreloaderBase::AddLoadBackgroundFlag(nsIChannel* aChannel) {
nsLoadFlags loadFlags;
aChannel->GetLoadFlags(&loadFlags);
aChannel->SetLoadFlags(loadFlags | nsIRequest::LOAD_BACKGROUND);
}
void PreloaderBase::NotifyOpen(const PreloadHashKey& aKey,
dom::Document* aDocument, bool aIsPreload,
bool aIsModule) {
if (aDocument) {
DebugOnly<bool> alreadyRegistered =
aDocument->Preloads().RegisterPreload(aKey, this);
// This means there is already a preload registered under this key in this
// document. We only allow replacement when this is a regular load.
// Otherwise, this should never happen and is a suspected misuse of the API.
MOZ_ASSERT_IF(alreadyRegistered, !aIsPreload);
}
mKey = aKey;
mIsUsed = !aIsPreload;
// Start usage timer for rel="preload", but not for rel="modulepreload"
// because modules may be loaded for functionality the user does not
// immediately interact with after page load (e.g. a docs search box)
if (!aIsModule && !mIsUsed && !mUsageTimer) {
auto callback = MakeRefPtr<UsageTimer>(this, aDocument);
NS_NewTimerWithCallback(getter_AddRefs(mUsageTimer), callback, 10000,
nsITimer::TYPE_ONE_SHOT);
}
ReportUsageTelemetry();
}
void PreloaderBase::NotifyOpen(const PreloadHashKey& aKey, nsIChannel* aChannel,
dom::Document* aDocument, bool aIsPreload,
bool aIsModule) {
NotifyOpen(aKey, aDocument, aIsPreload, aIsModule);
mChannel = aChannel;
nsCOMPtr<nsIInterfaceRequestor> callbacks;
mChannel->GetNotificationCallbacks(getter_AddRefs(callbacks));
RefPtr<RedirectSink> sink(new RedirectSink(this, callbacks));
mChannel->SetNotificationCallbacks(sink);
}
void PreloaderBase::NotifyUsage(dom::Document* aDocument,
LoadBackground aLoadBackground) {
if (!mIsUsed && mChannel && aLoadBackground == LoadBackground::Drop) {
nsLoadFlags loadFlags;
mChannel->GetLoadFlags(&loadFlags);
// Preloads are initially set the LOAD_BACKGROUND flag. When becoming
// regular loads by hitting its consuming tag, we need to drop that flag,
// which also means to re-add the request from/to it's loadgroup to reflect
// that flag change.
if (loadFlags & nsIRequest::LOAD_BACKGROUND) {
nsCOMPtr<nsILoadGroup> loadGroup;
mChannel->GetLoadGroup(getter_AddRefs(loadGroup));
if (loadGroup) {
nsresult status;
mChannel->GetStatus(&status);
nsresult rv = loadGroup->RemoveRequest(mChannel, nullptr, status);
mChannel->SetLoadFlags(loadFlags & ~nsIRequest::LOAD_BACKGROUND);
if (NS_SUCCEEDED(rv)) {
loadGroup->AddRequest(mChannel, nullptr);
}
}
}
}
mIsUsed = true;
ReportUsageTelemetry();
CancelUsageTimer();
if (mIsEarlyHintsPreload) {
aDocument->Preloads().SetEarlyHintUsed();
}
}
void PreloaderBase::RemoveSelf(dom::Document* aDocument) {
if (aDocument) {
aDocument->Preloads().DeregisterPreload(mKey);
}
}
void PreloaderBase::NotifyRestart(dom::Document* aDocument,
PreloaderBase* aNewPreloader) {
RemoveSelf(aDocument);
mKey = PreloadHashKey();
CancelUsageTimer();
if (aNewPreloader) {
aNewPreloader->mNodes = std::move(mNodes);
}
}
void PreloaderBase::NotifyStart(nsIRequest* aRequest) {
// If there is no channel assigned on this preloader, we are not between
// channel switching, so we can freely update the mShouldFireLoadEvent using
// the given channel.
if (mChannel && !SameCOMIdentity(aRequest, mChannel)) {
return;
}
nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(aRequest);
if (!httpChannel) {
return;
}
// if the load is cross origin without CORS, or the CORS access is rejected,
// always fire load event to avoid leaking site information.
nsresult rv;
nsCOMPtr<nsILoadInfo> loadInfo = httpChannel->LoadInfo();
mShouldFireLoadEvent =
loadInfo->GetTainting() == LoadTainting::Opaque ||
(loadInfo->GetTainting() == LoadTainting::CORS &&
(NS_FAILED(httpChannel->GetStatus(&rv)) || NS_FAILED(rv)));
}
void PreloaderBase::NotifyStop(nsIRequest* aRequest, nsresult aStatus) {
// Filter out notifications that may be arriving from the old channel before
// restarting this request.
if (!SameCOMIdentity(aRequest, mChannel)) {
return;
}
NotifyStop(aStatus);
}
void PreloaderBase::NotifyStop(nsresult aStatus) {
mOnStopStatus.emplace(aStatus);
nsTArray<nsWeakPtr> nodes = std::move(mNodes);
for (nsWeakPtr& weak : nodes) {
nsCOMPtr<nsINode> node = do_QueryReferent(weak);
if (node) {
NotifyNodeEvent(node);
}
}
mChannel = nullptr;
}
void PreloaderBase::AddLinkPreloadNode(nsINode* aNode) {
if (mOnStopStatus) {
return NotifyNodeEvent(aNode);
}
mNodes.AppendElement(do_GetWeakReference(aNode));
}
void PreloaderBase::RemoveLinkPreloadNode(nsINode* aNode) {
// Note that do_GetWeakReference returns the internal weak proxy, which is
// always the same, so we can use it to search the array using default
// comparator.
nsWeakPtr node = do_GetWeakReference(aNode);
mNodes.RemoveElement(node);
if (kCancelAndRemovePreloadOnZeroReferences && mNodes.Length() == 0 &&
!mIsUsed) {
// Keep a reference, because the following call may release us. The caller
// may use a WeakPtr to access this.
RefPtr<PreloaderBase> self(this);
RemoveSelf(aNode->OwnerDoc());
if (mChannel) {
mChannel->CancelWithReason(NS_BINDING_ABORTED,
"PreloaderBase::RemoveLinkPreloadNode"_ns);
}
}
}
void PreloaderBase::NotifyNodeEvent(nsINode* aNode) {
PreloadService::NotifyNodeEvent(
aNode, mShouldFireLoadEvent || NS_SUCCEEDED(*mOnStopStatus));
}
void PreloaderBase::CancelUsageTimer() {
if (mUsageTimer) {
mUsageTimer->Cancel();
mUsageTimer = nullptr;
}
}
void PreloaderBase::ReportUsageTelemetry() {
if (mUsageTelementryReported) {
return;
}
mUsageTelementryReported = true;
if (mKey.As() == PreloadHashKey::ResourceType::NONE) {
return;
}
// The labels are structured as type1-used, type1-unused, type2-used, ...
// The first "as" resource type is NONE with value 0.
auto index = (static_cast<uint32_t>(mKey.As()) - 1) * 2;
if (!mIsUsed) {
++index;
}
auto label = static_cast<Telemetry::LABELS_REL_PRELOAD_MISS_RATIO>(index);
Telemetry::AccumulateCategorical(label);
}
nsresult PreloaderBase::AsyncConsume(nsIStreamListener* aListener) {
// We want to return an error so that consumers can't ever use a preload to
// consume data unless it's properly implemented.
return NS_ERROR_NOT_IMPLEMENTED;
}
// PreloaderBase::RedirectRecord
nsCString PreloaderBase::RedirectRecord::Spec() const {
nsCOMPtr<nsIURI> noFragment;
NS_GetURIWithoutRef(mURI, getter_AddRefs(noFragment));
MOZ_ASSERT(noFragment);
return noFragment->GetSpecOrDefault();
}
nsCString PreloaderBase::RedirectRecord::Fragment() const {
nsCString fragment;
mURI->GetRef(fragment);
return fragment;
}
// PreloaderBase::UsageTimer
NS_IMPL_ISUPPORTS(PreloaderBase::UsageTimer, nsITimerCallback, nsINamed)
NS_IMETHODIMP PreloaderBase::UsageTimer::Notify(nsITimer* aTimer) {
if (!mPreload || !mDocument) {
return NS_OK;
}
MOZ_ASSERT(aTimer == mPreload->mUsageTimer);
mPreload->mUsageTimer = nullptr;
if (mPreload->IsUsed()) {
// Left in the hashtable, but marked as used. This is a valid case, and we
// don't want to emit a warning for this preload then.
return NS_OK;
}
mPreload->ReportUsageTelemetry();
// PreloadHashKey overrides GetKey, we need to use the nsURIHashKey one to get
// the URI.
nsIURI* uri = static_cast<nsURIHashKey*>(&mPreload->mKey)->GetKey();
if (!uri) {
return NS_OK;
}
nsString spec;
NS_GetSanitizedURIStringFromURI(uri, spec);
nsContentUtils::ReportToConsole(nsIScriptError::warningFlag, "DOM"_ns,
mDocument, nsContentUtils::eDOM_PROPERTIES,
"UnusedLinkPreloadPending",
nsTArray<nsString>({std::move(spec)}));
return NS_OK;
}
NS_IMETHODIMP
PreloaderBase::UsageTimer::GetName(nsACString& aName) {
aName.AssignLiteral("PreloaderBase::UsageTimer");
return NS_OK;
}
} // namespace mozilla