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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 ;*; */
/* vim: set sw=2 ts=8 et 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
#include "nsIDocShell.h"
#include "mozilla/dom/Document.h"
#include "nsComponentManagerUtils.h"
#include "nsIDocumentLoader.h"
#include "nsIObserverService.h"
#include "nsITimer.h"
#include "nsIXULRuntime.h"
#include "nsServiceManagerUtils.h"
#include "nsThreadUtils.h"
#include "RequestContextService.h"
#include "mozilla/Atomics.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/Logging.h"
#include "mozilla/Services.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/net/NeckoChild.h"
#include "mozilla/net/NeckoCommon.h"
#include "mozilla/net/PSpdyPush.h"
#include "../protocol/http/nsHttpHandler.h"
namespace mozilla {
namespace net {
LazyLogModule gRequestContextLog("RequestContext");
#undef LOG
#define LOG(args) MOZ_LOG(gRequestContextLog, LogLevel::Info, args)
static StaticRefPtr<RequestContextService> gSingleton;
// This is used to prevent adding tail pending requests after shutdown
static bool sShutdown = false;
// nsIRequestContext
class RequestContext final : public nsIRequestContext,
public nsITimerCallback,
public nsINamed {
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIREQUESTCONTEXT
NS_DECL_NSITIMERCALLBACK
NS_DECL_NSINAMED
explicit RequestContext(const uint64_t id);
private:
virtual ~RequestContext();
void ProcessTailQueue(nsresult aResult);
// Reschedules the timer if needed
void ScheduleUnblock();
// Hard-reschedules the timer
void RescheduleUntailTimer(TimeStamp const& now);
uint64_t mID;
Atomic<uint32_t> mBlockingTransactionCount;
UniquePtr<SpdyPushCache> mSpdyCache;
using PendingTailRequest = nsCOMPtr<nsIRequestTailUnblockCallback>;
// Number of known opened non-tailed requets
uint32_t mNonTailRequests;
// Queue of requests that have been tailed, when conditions are met
// we call each of them to unblock and drop the reference
nsTArray<PendingTailRequest> mTailQueue;
// Loosly scheduled timer, never scheduled further to the future than
// mUntailAt time
nsCOMPtr<nsITimer> mUntailTimer;
// Timestamp when the timer is expected to fire,
// always less than or equal to mUntailAt
TimeStamp mTimerScheduledAt;
// Timestamp when we want to actually untail queued requets based on
// the number of request count change in the past; iff this timestamp
// is set, we tail requests
TimeStamp mUntailAt;
// Timestamp of the navigation start time, set to Now() in BeginLoad().
// This is used to progressively lower the maximum delay time so that
// we can't get to a situation when a number of repetitive requests
// on the page causes forever tailing.
TimeStamp mBeginLoadTime;
// This member is true only between DOMContentLoaded notification and
// next document load beginning for this request context.
// Top level request contexts are recycled.
bool mAfterDOMContentLoaded;
};
NS_IMPL_ISUPPORTS(RequestContext, nsIRequestContext, nsITimerCallback, nsINamed)
RequestContext::RequestContext(const uint64_t aID)
: mID(aID),
mBlockingTransactionCount(0),
mNonTailRequests(0),
mAfterDOMContentLoaded(false) {
LOG(("RequestContext::RequestContext this=%p id=%" PRIx64, this, mID));
}
RequestContext::~RequestContext() {
MOZ_ASSERT(mTailQueue.Length() == 0);
LOG(("RequestContext::~RequestContext this=%p blockers=%u", this,
static_cast<uint32_t>(mBlockingTransactionCount)));
}
NS_IMETHODIMP
RequestContext::BeginLoad() {
MOZ_ASSERT(NS_IsMainThread());
LOG(("RequestContext::BeginLoad %p", this));
if (IsNeckoChild()) {
// Tailing is not supported on the child process
if (gNeckoChild) {
gNeckoChild->SendRequestContextLoadBegin(mID);
}
return NS_OK;
}
mAfterDOMContentLoaded = false;
mBeginLoadTime = TimeStamp::NowLoRes();
return NS_OK;
}
NS_IMETHODIMP
RequestContext::DOMContentLoaded() {
MOZ_ASSERT(NS_IsMainThread());
LOG(("RequestContext::DOMContentLoaded %p", this));
if (IsNeckoChild()) {
// Tailing is not supported on the child process
if (gNeckoChild) {
gNeckoChild->SendRequestContextAfterDOMContentLoaded(mID);
}
return NS_OK;
}
if (mAfterDOMContentLoaded) {
// There is a possibility of a duplicate notification
return NS_OK;
}
mAfterDOMContentLoaded = true;
// Conditions for the delay calculation has changed.
ScheduleUnblock();
return NS_OK;
}
NS_IMETHODIMP
RequestContext::GetBlockingTransactionCount(
uint32_t* aBlockingTransactionCount) {
NS_ENSURE_ARG_POINTER(aBlockingTransactionCount);
*aBlockingTransactionCount = mBlockingTransactionCount;
return NS_OK;
}
NS_IMETHODIMP
RequestContext::AddBlockingTransaction() {
mBlockingTransactionCount++;
LOG(("RequestContext::AddBlockingTransaction this=%p blockers=%u", this,
static_cast<uint32_t>(mBlockingTransactionCount)));
return NS_OK;
}
NS_IMETHODIMP
RequestContext::RemoveBlockingTransaction(uint32_t* outval) {
NS_ENSURE_ARG_POINTER(outval);
mBlockingTransactionCount--;
LOG(("RequestContext::RemoveBlockingTransaction this=%p blockers=%u", this,
static_cast<uint32_t>(mBlockingTransactionCount)));
*outval = mBlockingTransactionCount;
return NS_OK;
}
SpdyPushCache* RequestContext::GetSpdyPushCache() { return mSpdyCache.get(); }
void RequestContext::SetSpdyPushCache(SpdyPushCache* aSpdyPushCache) {
mSpdyCache = WrapUnique(aSpdyPushCache);
}
uint64_t RequestContext::GetID() { return mID; }
NS_IMETHODIMP
RequestContext::AddNonTailRequest() {
MOZ_ASSERT(NS_IsMainThread());
++mNonTailRequests;
LOG(("RequestContext::AddNonTailRequest this=%p, cnt=%u", this,
mNonTailRequests));
ScheduleUnblock();
return NS_OK;
}
NS_IMETHODIMP
RequestContext::RemoveNonTailRequest() {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(mNonTailRequests > 0);
LOG(("RequestContext::RemoveNonTailRequest this=%p, cnt=%u", this,
mNonTailRequests - 1));
--mNonTailRequests;
ScheduleUnblock();
return NS_OK;
}
void RequestContext::ScheduleUnblock() {
MOZ_ASSERT(!IsNeckoChild());
MOZ_ASSERT(NS_IsMainThread());
if (!gHttpHandler) {
return;
}
uint32_t quantum =
gHttpHandler->TailBlockingDelayQuantum(mAfterDOMContentLoaded);
uint32_t delayMax = gHttpHandler->TailBlockingDelayMax();
uint32_t totalMax = gHttpHandler->TailBlockingTotalMax();
if (!mBeginLoadTime.IsNull()) {
// We decrease the maximum delay progressively with the time since the page
// load begin. This seems like a reasonable and clear heuristic allowing us
// to start loading tailed requests in a deterministic time after the load
// has started.
uint32_t sinceBeginLoad = static_cast<uint32_t>(
(TimeStamp::NowLoRes() - mBeginLoadTime).ToMilliseconds());
uint32_t tillTotal = totalMax - std::min(sinceBeginLoad, totalMax);
uint32_t proportion = totalMax // values clamped between 0 and 60'000
? (delayMax * tillTotal) / totalMax
: 0;
delayMax = std::min(delayMax, proportion);
}
CheckedInt<uint32_t> delay = quantum * mNonTailRequests;
if (!mAfterDOMContentLoaded) {
// Before DOMContentLoaded notification we want to make sure that tailed
// requests don't start when there is a short delay during which we may
// not have any active requests on the page happening.
delay += quantum;
}
if (!delay.isValid() || delay.value() > delayMax) {
delay = delayMax;
}
LOG(
("RequestContext::ScheduleUnblock this=%p non-tails=%u tail-queue=%zu "
"delay=%u after-DCL=%d",
this, mNonTailRequests, mTailQueue.Length(), delay.value(),
mAfterDOMContentLoaded));
TimeStamp now = TimeStamp::NowLoRes();
mUntailAt = now + TimeDuration::FromMilliseconds(delay.value());
if (mTimerScheduledAt.IsNull() || mUntailAt < mTimerScheduledAt) {
LOG(("RequestContext %p timer would fire too late, rescheduling", this));
RescheduleUntailTimer(now);
}
}
void RequestContext::RescheduleUntailTimer(TimeStamp const& now) {
MOZ_ASSERT(mUntailAt >= now);
if (mUntailTimer) {
mUntailTimer->Cancel();
}
if (!mTailQueue.Length()) {
mUntailTimer = nullptr;
mTimerScheduledAt = TimeStamp();
return;
}
TimeDuration interval = mUntailAt - now;
if (!mTimerScheduledAt.IsNull() && mUntailAt < mTimerScheduledAt) {
// When the number of untailed requests goes down,
// let's half the interval, since it's likely we would
// reschedule for a shorter time again very soon.
// This will likely save rescheduling this timer.
interval = interval / int64_t(2);
mTimerScheduledAt = mUntailAt - interval;
} else {
mTimerScheduledAt = mUntailAt;
}
uint32_t delay = interval.ToMilliseconds();
nsresult rv =
NS_NewTimerWithCallback(getter_AddRefs(mUntailTimer), this, delay,
nsITimer::TYPE_ONE_SHOT, nullptr);
if (NS_FAILED(rv)) {
NS_WARNING("Could not reschedule untail timer");
}
LOG(("RequestContext::RescheduleUntailTimer %p in %d", this, delay));
}
NS_IMETHODIMP
RequestContext::Notify(nsITimer* timer) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(timer == mUntailTimer);
MOZ_ASSERT(!mTimerScheduledAt.IsNull());
MOZ_ASSERT(mTailQueue.Length());
mUntailTimer = nullptr;
TimeStamp now = TimeStamp::NowLoRes();
if (mUntailAt > mTimerScheduledAt && mUntailAt > now) {
LOG(("RequestContext %p timer fired too soon, rescheduling", this));
RescheduleUntailTimer(now);
return NS_OK;
}
// Must drop to allow re-engage of the timer
mTimerScheduledAt = TimeStamp();
ProcessTailQueue(NS_OK);
return NS_OK;
}
NS_IMETHODIMP
RequestContext::GetName(nsACString& aName) {
aName.AssignLiteral("RequestContext");
return NS_OK;
}
NS_IMETHODIMP
RequestContext::IsContextTailBlocked(nsIRequestTailUnblockCallback* aRequest,
bool* aBlocked) {
MOZ_ASSERT(NS_IsMainThread());
LOG(("RequestContext::IsContextTailBlocked this=%p, request=%p, queued=%zu",
this, aRequest, mTailQueue.Length()));
*aBlocked = false;
if (sShutdown) {
return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
}
if (mUntailAt.IsNull()) {
LOG((" untail time passed"));
return NS_OK;
}
if (mAfterDOMContentLoaded && !mNonTailRequests) {
LOG((" after DOMContentLoaded and no untailed requests"));
return NS_OK;
}
if (!gHttpHandler) {
// Xpcshell tests may not have http handler
LOG((" missing gHttpHandler?"));
return NS_OK;
}
*aBlocked = true;
mTailQueue.AppendElement(aRequest);
LOG((" request queued"));
if (!mUntailTimer) {
ScheduleUnblock();
}
return NS_OK;
}
NS_IMETHODIMP
RequestContext::CancelTailedRequest(nsIRequestTailUnblockCallback* aRequest) {
MOZ_ASSERT(NS_IsMainThread());
bool removed = mTailQueue.RemoveElement(aRequest);
LOG(("RequestContext::CancelTailedRequest %p req=%p removed=%d", this,
aRequest, removed));
// Stop untail timer if all tail requests are canceled.
if (removed && mTailQueue.IsEmpty()) {
if (mUntailTimer) {
mUntailTimer->Cancel();
mUntailTimer = nullptr;
}
// Must drop to allow re-engage of the timer
mTimerScheduledAt = TimeStamp();
}
return NS_OK;
}
void RequestContext::ProcessTailQueue(nsresult aResult) {
LOG(("RequestContext::ProcessTailQueue this=%p, queued=%zu, rv=%" PRIx32,
this, mTailQueue.Length(), static_cast<uint32_t>(aResult)));
if (mUntailTimer) {
mUntailTimer->Cancel();
mUntailTimer = nullptr;
}
// Must drop to stop tailing requests
mUntailAt = TimeStamp();
nsTArray<PendingTailRequest> queue = std::move(mTailQueue);
for (const auto& request : queue) {
LOG((" untailing %p", request.get()));
request->OnTailUnblock(aResult);
}
}
NS_IMETHODIMP
RequestContext::CancelTailPendingRequests(nsresult aResult) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(NS_FAILED(aResult));
ProcessTailQueue(aResult);
return NS_OK;
}
// nsIRequestContextService
RequestContextService* RequestContextService::sSelf = nullptr;
NS_IMPL_ISUPPORTS(RequestContextService, nsIRequestContextService, nsIObserver)
RequestContextService::RequestContextService() {
MOZ_ASSERT(!sSelf, "multiple rcs instances!");
MOZ_ASSERT(NS_IsMainThread());
sSelf = this;
nsCOMPtr<nsIXULRuntime> runtime = do_GetService("@mozilla.org/xre/runtime;1");
runtime->GetProcessID(&mRCIDNamespace);
}
RequestContextService::~RequestContextService() {
MOZ_ASSERT(NS_IsMainThread());
Shutdown();
sSelf = nullptr;
}
nsresult RequestContextService::Init() {
nsresult rv;
MOZ_ASSERT(NS_IsMainThread());
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (!obs) {
return NS_ERROR_NOT_AVAILABLE;
}
rv = obs->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
if (NS_FAILED(rv)) {
return rv;
}
obs->AddObserver(this, "content-document-interactive", false);
if (NS_FAILED(rv)) {
return rv;
}
return NS_OK;
}
void RequestContextService::Shutdown() {
MOZ_ASSERT(NS_IsMainThread());
// We need to do this to prevent the requests from being scheduled after
// shutdown.
for (const auto& data : mTable.Values()) {
data->CancelTailPendingRequests(NS_ERROR_ABORT);
}
mTable.Clear();
sShutdown = true;
}
/* static */
already_AddRefed<nsIRequestContextService>
RequestContextService::GetOrCreate() {
MOZ_ASSERT(NS_IsMainThread());
if (sShutdown) {
return nullptr;
}
RefPtr<RequestContextService> svc;
if (gSingleton) {
svc = gSingleton;
} else {
svc = new RequestContextService();
nsresult rv = svc->Init();
NS_ENSURE_SUCCESS(rv, nullptr);
gSingleton = svc;
ClearOnShutdown(&gSingleton);
}
return svc.forget();
}
NS_IMETHODIMP
RequestContextService::GetRequestContext(const uint64_t rcID,
nsIRequestContext** rc) {
MOZ_ASSERT(NS_IsMainThread());
NS_ENSURE_ARG_POINTER(rc);
*rc = nullptr;
if (sShutdown) {
return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
}
if (!rcID) {
return NS_ERROR_INVALID_ARG;
}
*rc = do_AddRef(mTable.LookupOrInsertWith(rcID, [&] {
nsCOMPtr<nsIRequestContext> newSC = new RequestContext(rcID);
return newSC;
})).take();
return NS_OK;
}
NS_IMETHODIMP
RequestContextService::GetRequestContextFromLoadGroup(nsILoadGroup* aLoadGroup,
nsIRequestContext** rc) {
nsresult rv;
uint64_t rcID;
rv = aLoadGroup->GetRequestContextID(&rcID);
if (NS_FAILED(rv)) {
return rv;
}
return GetRequestContext(rcID, rc);
}
NS_IMETHODIMP
RequestContextService::NewRequestContext(nsIRequestContext** rc) {
MOZ_ASSERT(NS_IsMainThread());
NS_ENSURE_ARG_POINTER(rc);
*rc = nullptr;
if (sShutdown) {
return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
}
uint64_t rcID =
((static_cast<uint64_t>(mRCIDNamespace) << 32) & 0xFFFFFFFF00000000LL) |
mNextRCID++;
nsCOMPtr<nsIRequestContext> newSC = new RequestContext(rcID);
mTable.InsertOrUpdate(rcID, newSC);
newSC.swap(*rc);
return NS_OK;
}
NS_IMETHODIMP
RequestContextService::RemoveRequestContext(const uint64_t rcID) {
MOZ_ASSERT(NS_IsMainThread());
mTable.Remove(rcID);
return NS_OK;
}
NS_IMETHODIMP
RequestContextService::Observe(nsISupports* subject, const char* topic,
const char16_t* data_unicode) {
MOZ_ASSERT(NS_IsMainThread());
if (!strcmp(NS_XPCOM_SHUTDOWN_OBSERVER_ID, topic)) {
Shutdown();
return NS_OK;
}
if (!strcmp("content-document-interactive", topic)) {
nsCOMPtr<dom::Document> document(do_QueryInterface(subject));
MOZ_ASSERT(document);
// We want this be triggered also for iframes, since those track their
// own request context ids.
if (!document) {
return NS_OK;
}
nsIDocShell* ds = document->GetDocShell();
// XML documents don't always have a docshell assigned
if (!ds) {
return NS_OK;
}
nsCOMPtr<nsIDocumentLoader> dl(do_QueryInterface(ds));
if (!dl) {
return NS_OK;
}
nsCOMPtr<nsILoadGroup> lg;
dl->GetLoadGroup(getter_AddRefs(lg));
if (!lg) {
return NS_OK;
}
nsCOMPtr<nsIRequestContext> rc;
GetRequestContextFromLoadGroup(lg, getter_AddRefs(rc));
if (rc) {
rc->DOMContentLoaded();
}
return NS_OK;
}
MOZ_ASSERT(false, "Unexpected observer topic");
return NS_OK;
}
} // namespace net
} // namespace mozilla
#undef LOG