image/ProgressTracker.cpp
author Kartikaya Gupta <kgupta@mozilla.com>
Thu, 15 Mar 2018 15:25:09 -0400
changeset 408344 a27ceb86fbd002b8aafd2f6377c315c11254af0c
parent 402771 62497967f092c6c76778ddc1534f110d4583eeb9
child 421523 dcf212d04876742f581acab5f428e703b54de82f
permissions -rw-r--r--
Bug 1445662 - Remove ProcessTouchVelocity from PAPZCTreeManager.ipdl. r=rhunt This function is never actually called over IPDL. It is called directly on the concrete APZCTreeManager instance by the AndroidDynamicToolbarAnimator code, both of which live in the compositor. So we don't need to expose this method on IAPZCTreeManager or over PAPZCTreeManager.

/* -*- 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 "ImageLogging.h"
#include "ProgressTracker.h"

#include "imgIContainer.h"
#include "imgINotificationObserver.h"
#include "imgIRequest.h"
#include "Image.h"
#include "nsNetUtil.h"
#include "nsIObserverService.h"

#include "mozilla/Assertions.h"
#include "mozilla/Services.h"
#include "mozilla/SystemGroup.h"

using mozilla::WeakPtr;

namespace mozilla {
namespace image {

static void
CheckProgressConsistency(Progress aOldProgress, Progress aNewProgress, bool aIsMultipart)
{
  // Check preconditions for every progress bit.

  // Error's do not get propagated from the tracker for each image part to the
  // tracker for the multipart image because we don't want one bad part to
  // prevent the remaining parts from showing. So we need to consider whether
  // this is a tracker for a multipart image for these assertions to work.

  if (aNewProgress & FLAG_SIZE_AVAILABLE) {
    // No preconditions.
  }
  if (aNewProgress & FLAG_DECODE_COMPLETE) {
    MOZ_ASSERT(aNewProgress & FLAG_SIZE_AVAILABLE);
    MOZ_ASSERT(aIsMultipart || aNewProgress & (FLAG_FRAME_COMPLETE | FLAG_HAS_ERROR));
  }
  if (aNewProgress & FLAG_FRAME_COMPLETE) {
    MOZ_ASSERT(aNewProgress & FLAG_SIZE_AVAILABLE);
  }
  if (aNewProgress & FLAG_LOAD_COMPLETE) {
    MOZ_ASSERT(aIsMultipart || aNewProgress & (FLAG_SIZE_AVAILABLE | FLAG_HAS_ERROR));
  }
  if (aNewProgress & FLAG_IS_ANIMATED) {
    // No preconditions; like FLAG_HAS_TRANSPARENCY, we should normally never
    // discover this *after* FLAG_SIZE_AVAILABLE, but unfortunately some corrupt
    // GIFs may fool us.
  }
  if (aNewProgress & FLAG_HAS_TRANSPARENCY) {
    // XXX We'd like to assert that transparency is only set during metadata
    // decode but we don't have any way to assert that until bug 1254892 is fixed.
  }
  if (aNewProgress & FLAG_LAST_PART_COMPLETE) {
    MOZ_ASSERT(aNewProgress & FLAG_LOAD_COMPLETE);
  }
  if (aNewProgress & FLAG_HAS_ERROR) {
    // No preconditions.
  }
}

ProgressTracker::ProgressTracker()
  : mMutex("ProgressTracker::mMutex")
  , mImage(nullptr)
  , mEventTarget(WrapNotNull(nsCOMPtr<nsIEventTarget>(SystemGroup::EventTargetFor(TaskCategory::Other))))
  , mObserversWithTargets(0)
  , mObservers(new ObserverTable)
  , mProgress(NoProgress)
  , mIsMultipart(false)
{ }

void
ProgressTracker::SetImage(Image* aImage)
{
  MutexAutoLock lock(mMutex);
  MOZ_ASSERT(aImage, "Setting null image");
  MOZ_ASSERT(!mImage, "Setting image when we already have one");
  mImage = aImage;
}

void
ProgressTracker::ResetImage()
{
  MutexAutoLock lock(mMutex);
  MOZ_ASSERT(mImage, "Resetting image when it's already null!");
  mImage = nullptr;
}

uint32_t
ProgressTracker::GetImageStatus() const
{
  uint32_t status = imgIRequest::STATUS_NONE;

  // Translate our current state to a set of imgIRequest::STATE_* flags.
  if (mProgress & FLAG_SIZE_AVAILABLE) {
    status |= imgIRequest::STATUS_SIZE_AVAILABLE;
  }
  if (mProgress & FLAG_DECODE_COMPLETE) {
    status |= imgIRequest::STATUS_DECODE_COMPLETE;
  }
  if (mProgress & FLAG_FRAME_COMPLETE) {
    status |= imgIRequest::STATUS_FRAME_COMPLETE;
  }
  if (mProgress & FLAG_LOAD_COMPLETE) {
    status |= imgIRequest::STATUS_LOAD_COMPLETE;
  }
  if (mProgress & FLAG_IS_ANIMATED) {
    status |= imgIRequest::STATUS_IS_ANIMATED;
  }
  if (mProgress & FLAG_HAS_TRANSPARENCY) {
    status |= imgIRequest::STATUS_HAS_TRANSPARENCY;
  }
  if (mProgress & FLAG_HAS_ERROR) {
    status |= imgIRequest::STATUS_ERROR;
  }

  return status;
}

// A helper class to allow us to call SyncNotify asynchronously.
class AsyncNotifyRunnable : public Runnable
{
  public:
    AsyncNotifyRunnable(ProgressTracker* aTracker,
                        IProgressObserver* aObserver)
     : Runnable("ProgressTracker::AsyncNotifyRunnable")
     , mTracker(aTracker)
    {
      MOZ_ASSERT(NS_IsMainThread(), "Should be created on the main thread");
      MOZ_ASSERT(aTracker, "aTracker should not be null");
      MOZ_ASSERT(aObserver, "aObserver should not be null");
      mObservers.AppendElement(aObserver);
    }

    NS_IMETHOD Run() override
    {
      MOZ_ASSERT(NS_IsMainThread(), "Should be running on the main thread");
      MOZ_ASSERT(mTracker, "mTracker should not be null");
      for (uint32_t i = 0; i < mObservers.Length(); ++i) {
        mObservers[i]->ClearPendingNotify();
        mTracker->SyncNotify(mObservers[i]);
      }

      mTracker->mRunnable = nullptr;
      return NS_OK;
    }

    void AddObserver(IProgressObserver* aObserver)
    {
      mObservers.AppendElement(aObserver);
    }

    void RemoveObserver(IProgressObserver* aObserver)
    {
      mObservers.RemoveElement(aObserver);
    }

  private:
    friend class ProgressTracker;

    RefPtr<ProgressTracker> mTracker;
    nsTArray<RefPtr<IProgressObserver>> mObservers;
};

void
ProgressTracker::Notify(IProgressObserver* aObserver)
{
  MOZ_ASSERT(NS_IsMainThread());

  if (aObserver->NotificationsDeferred()) {
    // There is a pending notification, or the observer isn't ready yet.
    return;
  }

  if (MOZ_LOG_TEST(gImgLog, LogLevel::Debug)) {
    RefPtr<Image> image = GetImage();
    if (image && image->GetURI()) {
      RefPtr<ImageURL> uri(image->GetURI());
      nsAutoCString spec;
      uri->GetSpec(spec);
      LOG_FUNC_WITH_PARAM(gImgLog,
                          "ProgressTracker::Notify async", "uri", spec.get());
    } else {
      LOG_FUNC_WITH_PARAM(gImgLog,
                          "ProgressTracker::Notify async", "uri", "<unknown>");
    }
  }

  aObserver->MarkPendingNotify();

  // If we have an existing runnable that we can use, we just append this
  // observer to its list of observers to be notified. This ensures we don't
  // unnecessarily delay onload.
  AsyncNotifyRunnable* runnable =
    static_cast<AsyncNotifyRunnable*>(mRunnable.get());

  if (runnable) {
    runnable->AddObserver(aObserver);
  } else {
    mRunnable = new AsyncNotifyRunnable(this, aObserver);
    mEventTarget->Dispatch(mRunnable, NS_DISPATCH_NORMAL);
  }
}

// A helper class to allow us to call SyncNotify asynchronously for a given,
// fixed, state.
class AsyncNotifyCurrentStateRunnable : public Runnable
{
  public:
    AsyncNotifyCurrentStateRunnable(ProgressTracker* aProgressTracker,
                                    IProgressObserver* aObserver)
      : Runnable("image::AsyncNotifyCurrentStateRunnable")
      , mProgressTracker(aProgressTracker)
      , mObserver(aObserver)
    {
      MOZ_ASSERT(NS_IsMainThread(), "Should be created on the main thread");
      MOZ_ASSERT(mProgressTracker, "mProgressTracker should not be null");
      MOZ_ASSERT(mObserver, "mObserver should not be null");
      mImage = mProgressTracker->GetImage();
    }

    NS_IMETHOD Run() override
    {
      MOZ_ASSERT(NS_IsMainThread(), "Should be running on the main thread");
      mObserver->ClearPendingNotify();

      mProgressTracker->SyncNotify(mObserver);
      return NS_OK;
    }

  private:
    RefPtr<ProgressTracker> mProgressTracker;
    RefPtr<IProgressObserver> mObserver;

    // We have to hold on to a reference to the tracker's image, just in case
    // it goes away while we're in the event queue.
    RefPtr<Image> mImage;
};

void
ProgressTracker::NotifyCurrentState(IProgressObserver* aObserver)
{
  MOZ_ASSERT(NS_IsMainThread());

  if (aObserver->NotificationsDeferred()) {
    // There is a pending notification, or the observer isn't ready yet.
    return;
  }

  if (MOZ_LOG_TEST(gImgLog, LogLevel::Debug)) {
    RefPtr<Image> image = GetImage();
    nsAutoCString spec;
    if (image && image->GetURI()) {
      image->GetURI()->GetSpec(spec);
    }
    LOG_FUNC_WITH_PARAM(gImgLog,
                        "ProgressTracker::NotifyCurrentState", "uri", spec.get());
  }

  aObserver->MarkPendingNotify();

  nsCOMPtr<nsIRunnable> ev = new AsyncNotifyCurrentStateRunnable(this,
                                                                 aObserver);
  mEventTarget->Dispatch(ev.forget(), NS_DISPATCH_NORMAL);
}

/**
 * ImageObserverNotifier is a helper type that abstracts over the difference
 * between sending notifications to all of the observers in an ObserverTable,
 * and sending them to a single observer. This allows the same notification code
 * to be used for both cases.
 */
template <typename T> struct ImageObserverNotifier;

template <>
struct MOZ_STACK_CLASS ImageObserverNotifier<const ObserverTable*>
{
  explicit ImageObserverNotifier(const ObserverTable* aObservers,
                                 bool aIgnoreDeferral = false)
    : mObservers(aObservers)
    , mIgnoreDeferral(aIgnoreDeferral)
  { }

  template <typename Lambda>
  void operator()(Lambda aFunc)
  {
    for (auto iter = mObservers->ConstIter(); !iter.Done(); iter.Next()) {
      RefPtr<IProgressObserver> observer = iter.Data().get();
      if (observer &&
          (mIgnoreDeferral || !observer->NotificationsDeferred())) {
        aFunc(observer);
      }
    }
  }

private:
  const ObserverTable* mObservers;
  const bool mIgnoreDeferral;
};

template <>
struct MOZ_STACK_CLASS ImageObserverNotifier<IProgressObserver*>
{
  explicit ImageObserverNotifier(IProgressObserver* aObserver)
    : mObserver(aObserver)
  { }

  template <typename Lambda>
  void operator()(Lambda aFunc)
  {
    if (mObserver && !mObserver->NotificationsDeferred()) {
      aFunc(mObserver);
    }
  }

private:
  IProgressObserver* mObserver;
};

template <typename T> void
SyncNotifyInternal(const T& aObservers,
                   bool aHasImage,
                   Progress aProgress,
                   const nsIntRect& aDirtyRect)
{
  MOZ_ASSERT(NS_IsMainThread());

  typedef imgINotificationObserver I;
  ImageObserverNotifier<T> notify(aObservers);

  if (aProgress & FLAG_SIZE_AVAILABLE) {
    notify([](IProgressObserver* aObs) { aObs->Notify(I::SIZE_AVAILABLE); });
  }

  if (aHasImage) {
    // OnFrameUpdate
    // If there's any content in this frame at all (always true for
    // vector images, true for raster images that have decoded at
    // least one frame) then send OnFrameUpdate.
    if (!aDirtyRect.IsEmpty()) {
      notify([&](IProgressObserver* aObs) {
        aObs->Notify(I::FRAME_UPDATE, &aDirtyRect);
      });
    }

    if (aProgress & FLAG_FRAME_COMPLETE) {
      notify([](IProgressObserver* aObs) { aObs->Notify(I::FRAME_COMPLETE); });
    }

    if (aProgress & FLAG_HAS_TRANSPARENCY) {
      notify([](IProgressObserver* aObs) { aObs->Notify(I::HAS_TRANSPARENCY); });
    }

    if (aProgress & FLAG_IS_ANIMATED) {
      notify([](IProgressObserver* aObs) { aObs->Notify(I::IS_ANIMATED); });
    }
  }

  if (aProgress & FLAG_DECODE_COMPLETE) {
    MOZ_ASSERT(aHasImage, "Stopped decoding without ever having an image?");
    notify([](IProgressObserver* aObs) { aObs->Notify(I::DECODE_COMPLETE); });
  }

  if (aProgress & FLAG_LOAD_COMPLETE) {
    notify([=](IProgressObserver* aObs) {
      aObs->OnLoadComplete(aProgress & FLAG_LAST_PART_COMPLETE);
    });
  }
}

void
ProgressTracker::SyncNotifyProgress(Progress aProgress,
                                    const nsIntRect& aInvalidRect
                                                  /* = nsIntRect() */)
{
  MOZ_ASSERT(NS_IsMainThread(), "Use mObservers on main thread only");

  Progress progress = Difference(aProgress);
  CheckProgressConsistency(mProgress, mProgress | progress, mIsMultipart);

  // Apply the changes.
  mProgress |= progress;

  // Send notifications.
  mObservers.Read([&](const ObserverTable* aTable) {
    SyncNotifyInternal(aTable, HasImage(), progress, aInvalidRect);
  });

  if (progress & FLAG_HAS_ERROR) {
    FireFailureNotification();
  }
}

void
ProgressTracker::SyncNotify(IProgressObserver* aObserver)
{
  MOZ_ASSERT(NS_IsMainThread());

  RefPtr<Image> image = GetImage();

  nsAutoCString spec;
  if (image && image->GetURI()) {
    image->GetURI()->GetSpec(spec);
  }
  LOG_SCOPE_WITH_PARAM(gImgLog,
                       "ProgressTracker::SyncNotify", "uri", spec.get());

  nsIntRect rect;
  if (image) {
    int32_t width, height;
    if (NS_FAILED(image->GetWidth(&width)) ||
        NS_FAILED(image->GetHeight(&height))) {
      // Either the image has no intrinsic size, or it has an error.
      rect = GetMaxSizedIntRect();
    } else {
      rect.SizeTo(width, height);
    }
  }

  SyncNotifyInternal(aObserver, !!image, mProgress, rect);
}

void
ProgressTracker::EmulateRequestFinished(IProgressObserver* aObserver)
{
  MOZ_ASSERT(NS_IsMainThread(),
             "SyncNotifyState and mObservers are not threadsafe");
  RefPtr<IProgressObserver> kungFuDeathGrip(aObserver);

  if (!(mProgress & FLAG_LOAD_COMPLETE)) {
    aObserver->OnLoadComplete(true);
  }
}

already_AddRefed<nsIEventTarget>
ProgressTracker::GetEventTarget() const
{
  MutexAutoLock lock(mMutex);
  nsCOMPtr<nsIEventTarget> target = mEventTarget;
  return target.forget();
}

void
ProgressTracker::AddObserver(IProgressObserver* aObserver)
{
  MOZ_ASSERT(NS_IsMainThread());
  RefPtr<IProgressObserver> observer = aObserver;

  nsCOMPtr<nsIEventTarget> target = observer->GetEventTarget();
  if (target) {
    if (mObserversWithTargets == 0) {
      // On the first observer with a target (i.e. listener), always accept its
      // event target; this may be for a specific DocGroup, or it may be the
      // unlabelled main thread target.
      MutexAutoLock lock(mMutex);
      mEventTarget = WrapNotNull(target);
    } else if (mEventTarget.get() != target.get()) {
      // If a subsequent observer comes in with a different target, we need to
      // switch to use the unlabelled main thread target, if we haven't already.
      MutexAutoLock lock(mMutex);
      nsCOMPtr<nsIEventTarget> mainTarget(do_GetMainThread());
      mEventTarget = WrapNotNull(mainTarget);
    }
    ++mObserversWithTargets;
  }

  mObservers.Write([=](ObserverTable* aTable) {
    MOZ_ASSERT(!aTable->Get(observer, nullptr),
               "Adding duplicate entry for image observer");

    WeakPtr<IProgressObserver> weakPtr = observer.get();
    aTable->Put(observer, weakPtr);
  });

  MOZ_ASSERT(mObserversWithTargets <= ObserverCount());
}

bool
ProgressTracker::RemoveObserver(IProgressObserver* aObserver)
{
  MOZ_ASSERT(NS_IsMainThread());
  RefPtr<IProgressObserver> observer = aObserver;

  // Remove the observer from the list.
  bool removed = mObservers.Write([observer](ObserverTable* aTable) {
    return aTable->Remove(observer);
  });

  // Sometimes once an image is decoded, and all of its observers removed, a new
  // document may request the same image. Thus we need to clear our event target
  // state when the last observer is removed, so that we select the most
  // appropriate event target when a new observer is added. Since the event
  // target may have changed (e.g. due to the scheduler group going away before
  // we were removed), so we should be cautious comparing this target against
  // anything at this stage.
  if (removed) {
    nsCOMPtr<nsIEventTarget> target = observer->GetEventTarget();
    if (target) {
      MOZ_ASSERT(mObserversWithTargets > 0);
      --mObserversWithTargets;

      if (mObserversWithTargets == 0) {
        MutexAutoLock lock(mMutex);
        nsCOMPtr<nsIEventTarget> target(SystemGroup::EventTargetFor(TaskCategory::Other));
        mEventTarget = WrapNotNull(target);
      }
    }

    MOZ_ASSERT(mObserversWithTargets <= ObserverCount());
  }

  // Observers can get confused if they don't get all the proper teardown
  // notifications. Part ways on good terms.
  if (removed && !aObserver->NotificationsDeferred()) {
    EmulateRequestFinished(aObserver);
  }

  // Make sure we don't give callbacks to an observer that isn't interested in
  // them any more.
  AsyncNotifyRunnable* runnable =
    static_cast<AsyncNotifyRunnable*>(mRunnable.get());

  if (aObserver->NotificationsDeferred() && runnable) {
    runnable->RemoveObserver(aObserver);
    aObserver->ClearPendingNotify();
  }

  return removed;
}

uint32_t
ProgressTracker::ObserverCount() const
{
  MOZ_ASSERT(NS_IsMainThread());
  return mObservers.Read([](const ObserverTable* aTable) {
    return aTable->Count();
  });
}

void
ProgressTracker::OnUnlockedDraw()
{
  MOZ_ASSERT(NS_IsMainThread());
  mObservers.Read([](const ObserverTable* aTable) {
    ImageObserverNotifier<const ObserverTable*> notify(aTable);
    notify([](IProgressObserver* aObs) {
      aObs->Notify(imgINotificationObserver::UNLOCKED_DRAW);
    });
  });
}

void
ProgressTracker::ResetForNewRequest()
{
  MOZ_ASSERT(NS_IsMainThread());
  mProgress = NoProgress;
}

void
ProgressTracker::OnDiscard()
{
  MOZ_ASSERT(NS_IsMainThread());
  mObservers.Read([](const ObserverTable* aTable) {
    ImageObserverNotifier<const ObserverTable*> notify(aTable);
    notify([](IProgressObserver* aObs) {
      aObs->Notify(imgINotificationObserver::DISCARD);
    });
  });
}

void
ProgressTracker::OnImageAvailable()
{
  MOZ_ASSERT(NS_IsMainThread());
  // Notify any imgRequestProxys that are observing us that we have an Image.
  mObservers.Read([](const ObserverTable* aTable) {
    ImageObserverNotifier<const ObserverTable*>
      notify(aTable, /* aIgnoreDeferral = */ true);
    notify([](IProgressObserver* aObs) {
      aObs->SetHasImage();
    });
  });
}

void
ProgressTracker::FireFailureNotification()
{
  MOZ_ASSERT(NS_IsMainThread());

  // Some kind of problem has happened with image decoding.
  // Report the URI to net:failed-to-process-uri-conent observers.
  RefPtr<Image> image = GetImage();
  if (image) {
    // Should be on main thread, so ok to create a new nsIURI.
    nsCOMPtr<nsIURI> uri;
    {
      RefPtr<ImageURL> threadsafeUriData = image->GetURI();
      uri = threadsafeUriData ? threadsafeUriData->ToIURI() : nullptr;
    }
    if (uri) {
      nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
      if (os) {
        os->NotifyObservers(uri, "net:failed-to-process-uri-content", nullptr);
      }
    }
  }
}

} // namespace image
} // namespace mozilla