author Masatoshi Kimura <>
Thu, 23 Feb 2017 06:10:07 +0900
changeset 379138 a072d7934ff7c6fd2ad974d7abc0b08d11041aca
parent 356028 6520346b0a23bda448e25df6b50ab309e940cdbd
child 411312 fd25a183897f665d70086ebd97033cb0f851c58c
permissions -rw-r--r--
Bug 1342144 - Remove version parameter from the type attribute of script elements. r=jmaher This patch is generated by the following sed script: find . ! -wholename '*/.hg*' -type f \( -iname '*.html' -o -iname '*.xhtml' -o -iname '*.xul' -o -iname '*.js' \) -exec sed -i -e 's/\(\(text\|application\)\/javascript\);version=1.[0-9]/\1/g' {} \; MozReview-Commit-ID: AzhtdwJwVNg

/* -*- 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 */

#ifndef mozilla_image_ProgressTracker_h
#define mozilla_image_ProgressTracker_h

#include "CopyOnWrite.h"
#include "mozilla/Mutex.h"
#include "mozilla/RefPtr.h"
#include "mozilla/WeakPtr.h"
#include "nsDataHashtable.h"
#include "nsCOMPtr.h"
#include "nsTObserverArray.h"
#include "nsThreadUtils.h"
#include "nsRect.h"
#include "IProgressObserver.h"

class nsIRunnable;

namespace mozilla {
namespace image {

class AsyncNotifyRunnable;
class AsyncNotifyCurrentStateRunnable;
class Image;

 * Image progress bitflags.
 * See CheckProgressConsistency() for the invariants we enforce about the
 * ordering dependencies betweeen these flags.
enum {
  FLAG_ONLOAD_BLOCKED     = 1u << 4,
  FLAG_HAS_ERROR          = 1u << 9   // STATUS_ERROR

typedef uint32_t Progress;

const uint32_t NoProgress = 0;

inline Progress LoadCompleteProgress(bool aLastPart,
                                     bool aError,
                                     nsresult aStatus)
  Progress progress = FLAG_LOAD_COMPLETE;
  if (aLastPart) {
    progress |= FLAG_LAST_PART_COMPLETE;
  if (NS_FAILED(aStatus) || aError) {
    progress |= FLAG_HAS_ERROR;
  return progress;

 * ProgressTracker stores its observers in an ObserverTable, which is a hash
 * table mapping raw pointers to WeakPtr's to the same objects. This sounds like
 * unnecessary duplication of information, but it's necessary for stable hash
 * values since WeakPtr's lose the knowledge of which object they used to point
 * to when that object is destroyed.
 * ObserverTable subclasses nsDataHashtable to add reference counting support
 * and a copy constructor, both of which are needed for use with CopyOnWrite<T>.
class ObserverTable
  : public nsDataHashtable<nsPtrHashKey<IProgressObserver>,

  ObserverTable() = default;

  ObserverTable(const ObserverTable& aOther)
    NS_WARNING("Forced to copy ObserverTable due to nested notifications");
    for (auto iter = aOther.ConstIter(); !iter.Done(); iter.Next()) {
      this->Put(iter.Key(), iter.Data());

  ~ObserverTable() { }

 * ProgressTracker is a class that records an Image's progress through the
 * loading and decoding process, and makes it possible to send notifications to
 * IProgressObservers, both synchronously and asynchronously.
 * When a new observer needs to be notified of the current progress of an image,
 * call the Notify() method on this class with the relevant observer as its
 * argument, and the notifications will be replayed to the observer
 * asynchronously.
class ProgressTracker : public mozilla::SupportsWeakPtr<ProgressTracker>
  virtual ~ProgressTracker() { }


    : mImageMutex("ProgressTracker::mImage")
    , mImage(nullptr)
    , mObservers(new ObserverTable)
    , mProgress(NoProgress)
    , mIsMultipart(false)
  { }

  bool HasImage() const { MutexAutoLock lock(mImageMutex); return mImage; }
  already_AddRefed<Image> GetImage() const
    MutexAutoLock lock(mImageMutex);
    RefPtr<Image> image = mImage;
    return image.forget();

  // Get the current image status (as in imgIRequest).
  uint32_t GetImageStatus() const;

  // Get the current Progress.
  Progress GetProgress() const { return mProgress; }

  // Schedule an asynchronous "replaying" of all the notifications that would
  // have to happen to put us in the current state.
  // We will also take note of any notifications that happen between the time
  // Notify() is called and when we call SyncNotify on |aObserver|, and replay
  // them as well.
  // Should be called on the main thread only, since observers and GetURI are
  // not threadsafe.
  void Notify(IProgressObserver* aObserver);

  // Schedule an asynchronous "replaying" of all the notifications that would
  // have to happen to put us in the state we are in right now.
  // Unlike Notify(), does *not* take into account future notifications.
  // This is only useful if you do not have an imgRequest, e.g., if you are a
  // static request returned from imgIRequest::GetStaticRequest().
  // Should be called on the main thread only, since observers and GetURI are
  // not threadsafe.
  void NotifyCurrentState(IProgressObserver* aObserver);

  // "Replay" all of the notifications that would have to happen to put us in
  // the state we're currently in.
  // Only use this if you're already servicing an asynchronous call (e.g.
  // OnStartRequest).
  // Should be called on the main thread only, since observers and GetURI are
  // not threadsafe.
  void SyncNotify(IProgressObserver* aObserver);

  // Get this ProgressTracker ready for a new request. This resets all the
  // state that doesn't persist between requests.
  void ResetForNewRequest();

  // Stateless notifications. These are dispatched and immediately forgotten
  // about. All of these notifications are main thread only.
  void OnDiscard();
  void OnUnlockedDraw();
  void OnImageAvailable();

  // Compute the difference between this our progress and aProgress. This allows
  // callers to predict whether SyncNotifyProgress will send any notifications.
  Progress Difference(Progress aProgress) const
    return ~mProgress & aProgress;

  // Update our state to incorporate the changes in aProgress and synchronously
  // notify our observers.
  // Because this may result in recursive notifications, no decoding locks may
  // be held.  Called on the main thread only.
  void SyncNotifyProgress(Progress aProgress,
                          const nsIntRect& aInvalidRect = nsIntRect());

  // We manage a set of observers that are using an image and thus concerned
  // with its loading progress. Weak pointers.
  void AddObserver(IProgressObserver* aObserver);
  bool RemoveObserver(IProgressObserver* aObserver);
  uint32_t ObserverCount() const;

  // Resets our weak reference to our image. Image subclasses should call this
  // in their destructor.
  void ResetImage();

  // Tell this progress tracker that it is for a multipart image.
  void SetIsMultipart() { mIsMultipart = true; }

  friend class AsyncNotifyRunnable;
  friend class AsyncNotifyCurrentStateRunnable;
  friend class ImageFactory;

  ProgressTracker(const ProgressTracker& aOther) = delete;

  // Sets our weak reference to our image. Only ImageFactory should call this.
  void SetImage(Image* aImage);

  // Send some notifications that would be necessary to make |aObserver| believe
  // the request is finished downloading and decoding.  We only send
  // FLAG_LOAD_COMPLETE and FLAG_ONLOAD_UNBLOCKED, and only if necessary.
  void EmulateRequestFinished(IProgressObserver* aObserver);

  // Main thread only because it deals with the observer service.
  void FireFailureNotification();

  // The runnable, if any, that we've scheduled to deliver async notifications.
  nsCOMPtr<nsIRunnable> mRunnable;

  // mImage is a weak ref; it should be set to null when the image goes out of
  // scope. mImageMutex protects mImage.
  mutable Mutex mImageMutex;
  Image* mImage;

  // Hashtable of observers attached to the image. Each observer represents a
  // consumer using the image. Main thread only.
  CopyOnWrite<ObserverTable> mObservers;

  Progress mProgress;

  // Whether this is a progress tracker for a multipart image.
  bool mIsMultipart;

} // namespace image
} // namespace mozilla

#endif // mozilla_image_ProgressTracker_h