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/* -*- 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/. */
#ifndef ProgressTracker_h__
#define ProgressTracker_h__
#include "mozilla/RefPtr.h"
#include "mozilla/WeakPtr.h"
#include "nsCOMPtr.h"
#include "nsTObserverArray.h"
#include "nsThreadUtils.h"
#include "nsRect.h"
#include "IProgressObserver.h"
class imgIContainer;
class nsIRunnable;
namespace mozilla {
namespace image {
class AsyncNotifyRunnable;
class AsyncNotifyCurrentStateRunnable;
class Image;
// Image progress bitflags.
enum {
FLAG_SIZE_AVAILABLE = 1u << 0, // STATUS_SIZE_AVAILABLE
FLAG_DECODE_STARTED = 1u << 1, // STATUS_DECODE_STARTED
FLAG_DECODE_COMPLETE = 1u << 2, // STATUS_DECODE_COMPLETE
FLAG_FRAME_COMPLETE = 1u << 3, // STATUS_FRAME_COMPLETE
FLAG_LOAD_COMPLETE = 1u << 4, // STATUS_LOAD_COMPLETE
FLAG_ONLOAD_BLOCKED = 1u << 5,
FLAG_ONLOAD_UNBLOCKED = 1u << 6,
FLAG_IS_ANIMATED = 1u << 7, // STATUS_IS_ANIMATED
FLAG_HAS_TRANSPARENCY = 1u << 8, // STATUS_HAS_TRANSPARENCY
FLAG_LAST_PART_COMPLETE = 1u << 9,
FLAG_HAS_ERROR = 1u << 10 // 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 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() { }
public:
MOZ_DECLARE_WEAKREFERENCE_TYPENAME(ProgressTracker)
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ProgressTracker)
ProgressTracker()
: mImage(nullptr)
, mProgress(NoProgress)
{ }
bool HasImage() const { return mImage; }
already_AddRefed<Image> GetImage() const
{
nsRefPtr<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 except OnImageAvailable 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);
size_t ObserverCount() const {
MOZ_ASSERT(NS_IsMainThread(), "Use mObservers on main thread only");
return mObservers.Length();
}
// This is intentionally non-general because its sole purpose is to support
// some obscure network priority logic in imgRequest. That stuff could
// probably be improved, but it's too scary to mess with at the moment.
bool FirstObserverIs(IProgressObserver* aObserver);
private:
typedef nsTObserverArray<mozilla::WeakPtr<IProgressObserver>> ObserverArray;
friend class AsyncNotifyRunnable;
friend class AsyncNotifyCurrentStateRunnable;
friend class ProgressTrackerInit;
ProgressTracker(const ProgressTracker& aOther) = delete;
// This method should only be called once, and only on an ProgressTracker
// that was initialized without an image. ProgressTrackerInit automates this.
void SetImage(Image* aImage);
// Resets our weak reference to our image, for when mImage is about to go out
// of scope. ProgressTrackerInit automates this.
void ResetImage();
// 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();
// Main thread only, since notifications are expected on the main thread, and
// mObservers is not threadsafe.
static void SyncNotifyInternal(ObserverArray& aObservers,
bool aHasImage, Progress aProgress,
const nsIntRect& aInvalidRect);
nsCOMPtr<nsIRunnable> mRunnable;
// This weak ref should be set null when the image goes out of scope.
Image* mImage;
// List of observers attached to the image. Each observer represents a
// consumer using the image. Array and/or individual elements should only be
// accessed on the main thread.
ObserverArray mObservers;
Progress mProgress;
};
class ProgressTrackerInit
{
public:
ProgressTrackerInit(Image* aImage, ProgressTracker* aTracker);
~ProgressTrackerInit();
private:
ProgressTracker* mTracker;
};
} // namespace image
} // namespace mozilla
#endif
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