image/ProgressTracker.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ImageLogging.h"
   8 #include "ProgressTracker.h"
   9
  10 #include "imgINotificationObserver.h"
  11 #include "imgIRequest.h"
  12 #include "Image.h"
  13 #include "nsNetUtil.h"
  14 #include "nsIObserverService.h"
  15
  16 #include "mozilla/Assertions.h"
  17 #include "mozilla/Services.h"
  18
  19 using mozilla::WeakPtr;
  20
  21 namespace mozilla {
  22 namespace image {
  23
  24 static void CheckProgressConsistency(Progress aOldProgress,
  25                                      Progress aNewProgress, bool aIsMultipart) {
  26   // Check preconditions for every progress bit.
  27
  28   // Error's do not get propagated from the tracker for each image part to the
  29   // tracker for the multipart image because we don't want one bad part to
  30   // prevent the remaining parts from showing. So we need to consider whether
  31   // this is a tracker for a multipart image for these assertions to work.
  32
  33   if (aNewProgress & FLAG_SIZE_AVAILABLE) {
  34     // No preconditions.
  35   }
  36   if (aNewProgress & FLAG_DECODE_COMPLETE) {
  37     MOZ_ASSERT(aNewProgress & FLAG_SIZE_AVAILABLE);
  38     MOZ_ASSERT(aIsMultipart ||
  39                aNewProgress & (FLAG_FRAME_COMPLETE | FLAG_HAS_ERROR));
  40   }
  41   if (aNewProgress & FLAG_FRAME_COMPLETE) {
  42     MOZ_ASSERT(aNewProgress & FLAG_SIZE_AVAILABLE);
  43   }
  44   if (aNewProgress & FLAG_LOAD_COMPLETE) {
  45     MOZ_ASSERT(aIsMultipart ||
  46                aNewProgress & (FLAG_SIZE_AVAILABLE | FLAG_HAS_ERROR));
  47   }
  48   if (aNewProgress & FLAG_IS_ANIMATED) {
  49     // No preconditions; like FLAG_HAS_TRANSPARENCY, we should normally never
  50     // discover this *after* FLAG_SIZE_AVAILABLE, but unfortunately some corrupt
  51     // GIFs may fool us.
  52   }
  53   if (aNewProgress & FLAG_HAS_TRANSPARENCY) {
  54     // XXX We'd like to assert that transparency is only set during metadata
  55     // decode but we don't have any way to assert that until bug 1254892 is
  56     // fixed.
  57   }
  58   if (aNewProgress & FLAG_LAST_PART_COMPLETE) {
  59     MOZ_ASSERT(aNewProgress & FLAG_LOAD_COMPLETE);
  60   }
  61   if (aNewProgress & FLAG_HAS_ERROR) {
  62     // No preconditions.
  63   }
  64 }
  65
  66 ProgressTracker::ProgressTracker()
  67     : mMutex("ProgressTracker::mMutex"),
  68       mImage(nullptr),
  69       mEventTarget(WrapNotNull(
  70           nsCOMPtr<nsIEventTarget>(GetMainThreadSerialEventTarget()))),
  71       mObserversWithTargets(0),
  72       mObservers(new ObserverTable),
  73       mProgress(NoProgress),
  74       mIsMultipart(false) {}
  75
  76 void ProgressTracker::SetImage(Image* aImage) {
  77   MutexAutoLock lock(mMutex);
  78   MOZ_ASSERT(aImage, "Setting null image");
  79   MOZ_ASSERT(!mImage, "Setting image when we already have one");
  80   mImage = aImage;
  81 }
  82
  83 void ProgressTracker::ResetImage() {
  84   MutexAutoLock lock(mMutex);
  85   MOZ_ASSERT(mImage, "Resetting image when it's already null!");
  86   mImage = nullptr;
  87 }
  88
  89 uint32_t ProgressTracker::GetImageStatus() const {
  90   uint32_t status = imgIRequest::STATUS_NONE;
  91
  92   // Translate our current state to a set of imgIRequest::STATE_* flags.
  93   if (mProgress & FLAG_SIZE_AVAILABLE) {
  94     status |= imgIRequest::STATUS_SIZE_AVAILABLE;
  95   }
  96   if (mProgress & FLAG_DECODE_COMPLETE) {
  97     status |= imgIRequest::STATUS_DECODE_COMPLETE;
  98   }
  99   if (mProgress & FLAG_FRAME_COMPLETE) {
 100     status |= imgIRequest::STATUS_FRAME_COMPLETE;
 101   }
 102   if (mProgress & FLAG_LOAD_COMPLETE) {
 103     status |= imgIRequest::STATUS_LOAD_COMPLETE;
 104   }
 105   if (mProgress & FLAG_IS_ANIMATED) {
 106     status |= imgIRequest::STATUS_IS_ANIMATED;
 107   }
 108   if (mProgress & FLAG_HAS_TRANSPARENCY) {
 109     status |= imgIRequest::STATUS_HAS_TRANSPARENCY;
 110   }
 111   if (mProgress & FLAG_HAS_ERROR) {
 112     status |= imgIRequest::STATUS_ERROR;
 113   }
 114
 115   return status;
 116 }
 117
 118 // A helper class to allow us to call SyncNotify asynchronously.
 119 class AsyncNotifyRunnable : public Runnable {
 120  public:
 121   AsyncNotifyRunnable(ProgressTracker* aTracker, IProgressObserver* aObserver)
 122       : Runnable("ProgressTracker::AsyncNotifyRunnable"), mTracker(aTracker) {
 123     MOZ_ASSERT(NS_IsMainThread(), "Should be created on the main thread");
 124     MOZ_ASSERT(aTracker, "aTracker should not be null");
 125     MOZ_ASSERT(aObserver, "aObserver should not be null");
 126     mObservers.AppendElement(aObserver);
 127   }
 128
 129   NS_IMETHOD Run() override {
 130     MOZ_ASSERT(NS_IsMainThread(), "Should be running on the main thread");
 131     MOZ_ASSERT(mTracker, "mTracker should not be null");
 132     for (uint32_t i = 0; i < mObservers.Length(); ++i) {
 133       mObservers[i]->ClearPendingNotify();
 134       mTracker->SyncNotify(mObservers[i]);
 135     }
 136
 137     mTracker->mRunnable = nullptr;
 138     return NS_OK;
 139   }
 140
 141   void AddObserver(IProgressObserver* aObserver) {
 142     mObservers.AppendElement(aObserver);
 143   }
 144
 145   void RemoveObserver(IProgressObserver* aObserver) {
 146     mObservers.RemoveElement(aObserver);
 147   }
 148
 149  private:
 150   friend class ProgressTracker;
 151
 152   RefPtr<ProgressTracker> mTracker;
 153   nsTArray<RefPtr<IProgressObserver>> mObservers;
 154 };
 155
 156 ProgressTracker::MediumHighRunnable::MediumHighRunnable(
 157     already_AddRefed<AsyncNotifyRunnable>&& aEvent)
 158     : PrioritizableRunnable(std::move(aEvent),
 159                             nsIRunnablePriority::PRIORITY_MEDIUMHIGH) {}
 160
 161 void ProgressTracker::MediumHighRunnable::AddObserver(
 162     IProgressObserver* aObserver) {
 163   static_cast<AsyncNotifyRunnable*>(mRunnable.get())->AddObserver(aObserver);
 164 }
 165
 166 void ProgressTracker::MediumHighRunnable::RemoveObserver(
 167     IProgressObserver* aObserver) {
 168   static_cast<AsyncNotifyRunnable*>(mRunnable.get())->RemoveObserver(aObserver);
 169 }
 170
 171 /* static */
 172 already_AddRefed<ProgressTracker::MediumHighRunnable>
 173 ProgressTracker::MediumHighRunnable::Create(
 174     already_AddRefed<AsyncNotifyRunnable>&& aEvent) {
 175   MOZ_ASSERT(NS_IsMainThread());
 176   RefPtr<ProgressTracker::MediumHighRunnable> event(
 177       new ProgressTracker::MediumHighRunnable(std::move(aEvent)));
 178   return event.forget();
 179 }
 180
 181 void ProgressTracker::Notify(IProgressObserver* aObserver) {
 182   MOZ_ASSERT(NS_IsMainThread());
 183
 184   if (aObserver->NotificationsDeferred()) {
 185     // There is a pending notification, or the observer isn't ready yet.
 186     return;
 187   }
 188
 189   if (MOZ_LOG_TEST(gImgLog, LogLevel::Debug)) {
 190     RefPtr<Image> image = GetImage();
 191     LOG_FUNC_WITH_PARAM(gImgLog, "ProgressTracker::Notify async", "uri", image);
 192   }
 193
 194   aObserver->MarkPendingNotify();
 195
 196   // If we have an existing runnable that we can use, we just append this
 197   // observer to its list of observers to be notified. This ensures we don't
 198   // unnecessarily delay onload.
 199   if (mRunnable) {
 200     mRunnable->AddObserver(aObserver);
 201   } else {
 202     RefPtr<AsyncNotifyRunnable> ev = new AsyncNotifyRunnable(this, aObserver);
 203     mRunnable = ProgressTracker::MediumHighRunnable::Create(ev.forget());
 204     mEventTarget->Dispatch(mRunnable, NS_DISPATCH_NORMAL);
 205   }
 206 }
 207
 208 // A helper class to allow us to call SyncNotify asynchronously for a given,
 209 // fixed, state.
 210 class AsyncNotifyCurrentStateRunnable : public Runnable {
 211  public:
 212   AsyncNotifyCurrentStateRunnable(ProgressTracker* aProgressTracker,
 213                                   IProgressObserver* aObserver)
 214       : Runnable("image::AsyncNotifyCurrentStateRunnable"),
 215         mProgressTracker(aProgressTracker),
 216         mObserver(aObserver) {
 217     MOZ_ASSERT(NS_IsMainThread(), "Should be created on the main thread");
 218     MOZ_ASSERT(mProgressTracker, "mProgressTracker should not be null");
 219     MOZ_ASSERT(mObserver, "mObserver should not be null");
 220     mImage = mProgressTracker->GetImage();
 221   }
 222
 223   NS_IMETHOD Run() override {
 224     MOZ_ASSERT(NS_IsMainThread(), "Should be running on the main thread");
 225     mObserver->ClearPendingNotify();
 226
 227     mProgressTracker->SyncNotify(mObserver);
 228     return NS_OK;
 229   }
 230
 231  private:
 232   RefPtr<ProgressTracker> mProgressTracker;
 233   RefPtr<IProgressObserver> mObserver;
 234
 235   // We have to hold on to a reference to the tracker's image, just in case
 236   // it goes away while we're in the event queue.
 237   RefPtr<Image> mImage;
 238 };
 239
 240 void ProgressTracker::NotifyCurrentState(IProgressObserver* aObserver) {
 241   MOZ_ASSERT(NS_IsMainThread());
 242
 243   if (aObserver->NotificationsDeferred()) {
 244     // There is a pending notification, or the observer isn't ready yet.
 245     return;
 246   }
 247
 248   if (MOZ_LOG_TEST(gImgLog, LogLevel::Debug)) {
 249     RefPtr<Image> image = GetImage();
 250     LOG_FUNC_WITH_PARAM(gImgLog, "ProgressTracker::NotifyCurrentState", "uri",
 251                         image);
 252   }
 253
 254   aObserver->MarkPendingNotify();
 255
 256   nsCOMPtr<nsIRunnable> ev =
 257       new AsyncNotifyCurrentStateRunnable(this, aObserver);
 258   mEventTarget->Dispatch(ev.forget(), NS_DISPATCH_NORMAL);
 259 }
 260
 261 /**
 262  * ImageObserverNotifier is a helper type that abstracts over the difference
 263  * between sending notifications to all of the observers in an ObserverTable,
 264  * and sending them to a single observer. This allows the same notification code
 265  * to be used for both cases.
 266  */
 267 template <typename T>
 268 struct ImageObserverNotifier;
 269
 270 template <>
 271 struct MOZ_STACK_CLASS ImageObserverNotifier<const ObserverTable*> {
 272   explicit ImageObserverNotifier(const ObserverTable* aObservers,
 273                                  bool aIgnoreDeferral = false)
 274       : mObservers(aObservers), mIgnoreDeferral(aIgnoreDeferral) {}
 275
 276   template <typename Lambda>
 277   void operator()(Lambda aFunc) {
 278     for (const auto& weakObserver : mObservers->Values()) {
 279       RefPtr<IProgressObserver> observer = weakObserver.get();
 280       if (observer && (mIgnoreDeferral || !observer->NotificationsDeferred())) {
 281         aFunc(observer);
 282       }
 283     }
 284   }
 285
 286  private:
 287   const ObserverTable* mObservers;
 288   const bool mIgnoreDeferral;
 289 };
 290
 291 template <>
 292 struct MOZ_STACK_CLASS ImageObserverNotifier<IProgressObserver*> {
 293   explicit ImageObserverNotifier(IProgressObserver* aObserver)
 294       : mObserver(aObserver) {}
 295
 296   template <typename Lambda>
 297   void operator()(Lambda aFunc) {
 298     if (mObserver && !mObserver->NotificationsDeferred()) {
 299       aFunc(mObserver);
 300     }
 301   }
 302
 303  private:
 304   IProgressObserver* mObserver;
 305 };
 306
 307 template <typename T>
 308 void SyncNotifyInternal(const T& aObservers, bool aHasImage, Progress aProgress,
 309                         const nsIntRect& aDirtyRect) {
 310   MOZ_ASSERT(NS_IsMainThread());
 311
 312   typedef imgINotificationObserver I;
 313   ImageObserverNotifier<T> notify(aObservers);
 314
 315   if (aProgress & FLAG_SIZE_AVAILABLE) {
 316     notify([](IProgressObserver* aObs) { aObs->Notify(I::SIZE_AVAILABLE); });
 317   }
 318
 319   if (aHasImage) {
 320     // OnFrameUpdate
 321     // If there's any content in this frame at all (always true for
 322     // vector images, true for raster images that have decoded at
 323     // least one frame) then send OnFrameUpdate.
 324     if (!aDirtyRect.IsEmpty()) {
 325       notify([&](IProgressObserver* aObs) {
 326         aObs->Notify(I::FRAME_UPDATE, &aDirtyRect);
 327       });
 328     }
 329
 330     if (aProgress & FLAG_FRAME_COMPLETE) {
 331       notify([](IProgressObserver* aObs) { aObs->Notify(I::FRAME_COMPLETE); });
 332     }
 333
 334     if (aProgress & FLAG_HAS_TRANSPARENCY) {
 335       notify(
 336           [](IProgressObserver* aObs) { aObs->Notify(I::HAS_TRANSPARENCY); });
 337     }
 338
 339     if (aProgress & FLAG_IS_ANIMATED) {
 340       notify([](IProgressObserver* aObs) { aObs->Notify(I::IS_ANIMATED); });
 341     }
 342   }
 343
 344   if (aProgress & FLAG_DECODE_COMPLETE) {
 345     MOZ_ASSERT(aHasImage, "Stopped decoding without ever having an image?");
 346     notify([](IProgressObserver* aObs) { aObs->Notify(I::DECODE_COMPLETE); });
 347   }
 348
 349   if (aProgress & FLAG_LOAD_COMPLETE) {
 350     notify([=](IProgressObserver* aObs) {
 351       aObs->OnLoadComplete(aProgress & FLAG_LAST_PART_COMPLETE);
 352     });
 353   }
 354 }
 355
 356 void ProgressTracker::SyncNotifyProgress(Progress aProgress,
 357                                          const nsIntRect& aInvalidRect
 358                                          /* = nsIntRect() */) {
 359   MOZ_ASSERT(NS_IsMainThread(), "Use mObservers on main thread only");
 360
 361   Progress progress = Difference(aProgress);
 362   CheckProgressConsistency(mProgress, mProgress | progress, mIsMultipart);
 363
 364   // Apply the changes.
 365   mProgress |= progress;
 366
 367   // Send notifications.
 368   mObservers.Read([&](const ObserverTable* aTable) {
 369     SyncNotifyInternal(aTable, HasImage(), progress, aInvalidRect);
 370   });
 371
 372   if (progress & FLAG_HAS_ERROR) {
 373     FireFailureNotification();
 374   }
 375 }
 376
 377 void ProgressTracker::SyncNotify(IProgressObserver* aObserver) {
 378   MOZ_ASSERT(NS_IsMainThread());
 379
 380   RefPtr<Image> image = GetImage();
 381   LOG_SCOPE_WITH_PARAM(gImgLog, "ProgressTracker::SyncNotify", "uri", image);
 382
 383   nsIntRect rect;
 384   if (image) {
 385     int32_t width, height;
 386     if (NS_FAILED(image->GetWidth(&width)) ||
 387         NS_FAILED(image->GetHeight(&height))) {
 388       // Either the image has no intrinsic size, or it has an error.
 389       rect = GetMaxSizedIntRect();
 390     } else {
 391       rect.SizeTo(width, height);
 392     }
 393   }
 394
 395   SyncNotifyInternal(aObserver, !!image, mProgress, rect);
 396 }
 397
 398 void ProgressTracker::EmulateRequestFinished(IProgressObserver* aObserver) {
 399   MOZ_ASSERT(NS_IsMainThread(),
 400              "SyncNotifyState and mObservers are not threadsafe");
 401   RefPtr<IProgressObserver> kungFuDeathGrip(aObserver);
 402
 403   if (!(mProgress & FLAG_LOAD_COMPLETE)) {
 404     aObserver->OnLoadComplete(true);
 405   }
 406 }
 407
 408 already_AddRefed<nsIEventTarget> ProgressTracker::GetEventTarget() const {
 409   MutexAutoLock lock(mMutex);
 410   nsCOMPtr<nsIEventTarget> target = mEventTarget;
 411   return target.forget();
 412 }
 413
 414 void ProgressTracker::AddObserver(IProgressObserver* aObserver) {
 415   MOZ_ASSERT(NS_IsMainThread());
 416   RefPtr<IProgressObserver> observer = aObserver;
 417
 418   nsCOMPtr<nsIEventTarget> target = observer->GetEventTarget();
 419   if (target) {
 420     if (mObserversWithTargets == 0) {
 421       // On the first observer with a target (i.e. listener), always accept its
 422       // event target; this may be for a specific DocGroup, or it may be the
 423       // unlabelled main thread target.
 424       MutexAutoLock lock(mMutex);
 425       mEventTarget = WrapNotNull(target);
 426     } else if (mEventTarget.get() != target.get()) {
 427       // If a subsequent observer comes in with a different target, we need to
 428       // switch to use the unlabelled main thread target, if we haven't already.
 429       MutexAutoLock lock(mMutex);
 430       nsCOMPtr<nsIEventTarget> mainTarget(do_GetMainThread());
 431       mEventTarget = WrapNotNull(mainTarget);
 432     }
 433     ++mObserversWithTargets;
 434   }
 435
 436   mObservers.Write([=](ObserverTable* aTable) {
 437     MOZ_ASSERT(!aTable->Contains(observer),
 438                "Adding duplicate entry for image observer");
 439
 440     WeakPtr<IProgressObserver> weakPtr = observer.get();
 441     aTable->InsertOrUpdate(observer, weakPtr);
 442   });
 443
 444   MOZ_ASSERT(mObserversWithTargets <= ObserverCount());
 445 }
 446
 447 bool ProgressTracker::RemoveObserver(IProgressObserver* aObserver) {
 448   MOZ_ASSERT(NS_IsMainThread());
 449   RefPtr<IProgressObserver> observer = aObserver;
 450
 451   // Remove the observer from the list.
 452   bool removed = mObservers.Write(
 453       [observer](ObserverTable* aTable) { return aTable->Remove(observer); });
 454
 455   // Sometimes once an image is decoded, and all of its observers removed, a new
 456   // document may request the same image. Thus we need to clear our event target
 457   // state when the last observer is removed, so that we select the most
 458   // appropriate event target when a new observer is added. Since the event
 459   // target may have changed (e.g. due to the scheduler group going away before
 460   // we were removed), so we should be cautious comparing this target against
 461   // anything at this stage.
 462   if (removed) {
 463     nsCOMPtr<nsIEventTarget> target = observer->GetEventTarget();
 464     if (target) {
 465       MOZ_ASSERT(mObserversWithTargets > 0);
 466       --mObserversWithTargets;
 467
 468       // If we've shutdown the main thread there's no need to update
 469       // event targets.
 470       if ((mObserversWithTargets == 0) && !gXPCOMThreadsShutDown) {
 471         MutexAutoLock lock(mMutex);
 472         nsCOMPtr<nsIEventTarget> target(do_GetMainThread());
 473         mEventTarget = WrapNotNull(target);
 474       }
 475     }
 476
 477     MOZ_ASSERT(mObserversWithTargets <= ObserverCount());
 478   }
 479
 480   // Observers can get confused if they don't get all the proper teardown
 481   // notifications. Part ways on good terms.
 482   if (removed && !aObserver->NotificationsDeferred()) {
 483     EmulateRequestFinished(aObserver);
 484   }
 485
 486   // Make sure we don't give callbacks to an observer that isn't interested in
 487   // them any more.
 488   if (aObserver->NotificationsDeferred() && mRunnable) {
 489     mRunnable->RemoveObserver(aObserver);
 490     aObserver->ClearPendingNotify();
 491   }
 492
 493   return removed;
 494 }
 495
 496 uint32_t ProgressTracker::ObserverCount() const {
 497   MOZ_ASSERT(NS_IsMainThread());
 498   return mObservers.Read(
 499       [](const ObserverTable* aTable) { return aTable->Count(); });
 500 }
 501
 502 void ProgressTracker::OnUnlockedDraw() {
 503   MOZ_ASSERT(NS_IsMainThread());
 504   mObservers.Read([](const ObserverTable* aTable) {
 505     ImageObserverNotifier<const ObserverTable*> notify(aTable);
 506     notify([](IProgressObserver* aObs) {
 507       aObs->Notify(imgINotificationObserver::UNLOCKED_DRAW);
 508     });
 509   });
 510 }
 511
 512 void ProgressTracker::ResetForNewRequest() {
 513   MOZ_ASSERT(NS_IsMainThread());
 514   mProgress = NoProgress;
 515 }
 516
 517 void ProgressTracker::OnDiscard() {
 518   MOZ_ASSERT(NS_IsMainThread());
 519   mObservers.Read([](const ObserverTable* aTable) {
 520     ImageObserverNotifier<const ObserverTable*> notify(aTable);
 521     notify([](IProgressObserver* aObs) {
 522       aObs->Notify(imgINotificationObserver::DISCARD);
 523     });
 524   });
 525 }
 526
 527 void ProgressTracker::OnImageAvailable() {
 528   MOZ_ASSERT(NS_IsMainThread());
 529   // Notify any imgRequestProxys that are observing us that we have an Image.
 530   mObservers.Read([](const ObserverTable* aTable) {
 531     ImageObserverNotifier<const ObserverTable*> notify(
 532         aTable, /* aIgnoreDeferral = */ true);
 533     notify([](IProgressObserver* aObs) { aObs->SetHasImage(); });
 534   });
 535 }
 536
 537 void ProgressTracker::FireFailureNotification() {
 538   MOZ_ASSERT(NS_IsMainThread());
 539
 540   // Some kind of problem has happened with image decoding.
 541   // Report the URI to net:failed-to-process-uri-conent observers.
 542   RefPtr<Image> image = GetImage();
 543   if (image) {
 544     // Should be on main thread, so ok to create a new nsIURI.
 545     nsCOMPtr<nsIURI> uri = image->GetURI();
 546     if (uri) {
 547       nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
 548       if (os) {
 549         os->NotifyObservers(uri, "net:failed-to-process-uri-content", nullptr);
 550       }
 551     }
 552   }
 553 }
 554
 555 }  // namespace image
 556 }  // namespace mozilla