image/IDecodingTask.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "IDecodingTask.h"
   7
   8 #include "nsThreadUtils.h"
   9 #include "mozilla/AppShutdown.h"
  10
  11 #include "Decoder.h"
  12 #include "DecodePool.h"
  13 #include "RasterImage.h"
  14 #include "SurfaceCache.h"
  15
  16 namespace mozilla {
  17
  18 using gfx::IntRect;
  19
  20 namespace image {
  21
  22 ///////////////////////////////////////////////////////////////////////////////
  23 // Helpers for sending notifications to the image associated with a decoder.
  24 ///////////////////////////////////////////////////////////////////////////////
  25
  26 void IDecodingTask::NotifyProgress(NotNull<RasterImage*> aImage,
  27                                    NotNull<Decoder*> aDecoder) {
  28   MOZ_ASSERT(aDecoder->HasProgress() && !aDecoder->IsMetadataDecode());
  29
  30   // Capture the decoder's state. If we need to notify asynchronously, it's
  31   // important that we don't wait until the lambda actually runs to capture the
  32   // state that we're going to notify. That would both introduce data races on
  33   // the decoder's state and cause inconsistencies between the NotifyProgress()
  34   // calls we make off-main-thread and the notifications that RasterImage
  35   // actually receives, which would cause bugs.
  36   Progress progress = aDecoder->TakeProgress();
  37   OrientedIntRect invalidRect = aDecoder->TakeInvalidRect();
  38   Maybe<uint32_t> frameCount = aDecoder->TakeCompleteFrameCount();
  39   DecoderFlags decoderFlags = aDecoder->GetDecoderFlags();
  40   SurfaceFlags surfaceFlags = aDecoder->GetSurfaceFlags();
  41
  42   // Synchronously notify if we can.
  43   if (NS_IsMainThread() && !(decoderFlags & DecoderFlags::ASYNC_NOTIFY)) {
  44     aImage->NotifyProgress(progress, invalidRect, frameCount, decoderFlags,
  45                            surfaceFlags);
  46     return;
  47   }
  48
  49   // Don't try to dispatch after shutdown, we'll just leak the runnable.
  50   if (NS_WARN_IF(
  51           AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdownThreads))) {
  52     return;
  53   }
  54
  55   // We're forced to notify asynchronously.
  56   NotNull<RefPtr<RasterImage>> image = aImage;
  57   nsCOMPtr<nsIEventTarget> eventTarget = GetMainThreadSerialEventTarget();
  58   eventTarget->Dispatch(CreateRenderBlockingRunnable(NS_NewRunnableFunction(
  59                             "IDecodingTask::NotifyProgress",
  60                             [=]() -> void {
  61                               image->NotifyProgress(progress, invalidRect,
  62                                                     frameCount, decoderFlags,
  63                                                     surfaceFlags);
  64                             })),
  65                         NS_DISPATCH_NORMAL);
  66 }
  67
  68 void IDecodingTask::NotifyDecodeComplete(NotNull<RasterImage*> aImage,
  69                                          NotNull<Decoder*> aDecoder) {
  70   MOZ_ASSERT(aDecoder->HasError() || !aDecoder->InFrame(),
  71              "Decode complete in the middle of a frame?");
  72
  73   // Capture the decoder's state.
  74   DecoderFinalStatus finalStatus = aDecoder->FinalStatus();
  75   ImageMetadata metadata = aDecoder->GetImageMetadata();
  76   DecoderTelemetry telemetry = aDecoder->Telemetry();
  77   Progress progress = aDecoder->TakeProgress();
  78   OrientedIntRect invalidRect = aDecoder->TakeInvalidRect();
  79   Maybe<uint32_t> frameCount = aDecoder->TakeCompleteFrameCount();
  80   DecoderFlags decoderFlags = aDecoder->GetDecoderFlags();
  81   SurfaceFlags surfaceFlags = aDecoder->GetSurfaceFlags();
  82
  83   // Synchronously notify if we can.
  84   if (NS_IsMainThread() && !(decoderFlags & DecoderFlags::ASYNC_NOTIFY)) {
  85     aImage->NotifyDecodeComplete(finalStatus, metadata, telemetry, progress,
  86                                  invalidRect, frameCount, decoderFlags,
  87                                  surfaceFlags);
  88     return;
  89   }
  90
  91   // Don't try to dispatch after shutdown, we'll just leak the runnable.
  92   if (NS_WARN_IF(
  93           AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdownThreads))) {
  94     return;
  95   }
  96
  97   // We're forced to notify asynchronously.
  98   NotNull<RefPtr<RasterImage>> image = aImage;
  99   nsCOMPtr<nsIEventTarget> eventTarget = GetMainThreadSerialEventTarget();
 100   eventTarget->Dispatch(CreateRenderBlockingRunnable(NS_NewRunnableFunction(
 101                             "IDecodingTask::NotifyDecodeComplete",
 102                             [=]() -> void {
 103                               image->NotifyDecodeComplete(
 104                                   finalStatus, metadata, telemetry, progress,
 105                                   invalidRect, frameCount, decoderFlags,
 106                                   surfaceFlags);
 107                             })),
 108                         NS_DISPATCH_NORMAL);
 109 }
 110
 111 ///////////////////////////////////////////////////////////////////////////////
 112 // IDecodingTask implementation.
 113 ///////////////////////////////////////////////////////////////////////////////
 114
 115 void IDecodingTask::Resume() { DecodePool::Singleton()->AsyncRun(this); }
 116
 117 ///////////////////////////////////////////////////////////////////////////////
 118 // MetadataDecodingTask implementation.
 119 ///////////////////////////////////////////////////////////////////////////////
 120
 121 MetadataDecodingTask::MetadataDecodingTask(NotNull<Decoder*> aDecoder)
 122     : mMutex("mozilla::image::MetadataDecodingTask"), mDecoder(aDecoder) {
 123   MOZ_ASSERT(mDecoder->IsMetadataDecode(),
 124              "Use DecodingTask for non-metadata decodes");
 125 }
 126
 127 void MetadataDecodingTask::Run() {
 128   MutexAutoLock lock(mMutex);
 129
 130   LexerResult result = mDecoder->Decode(WrapNotNull(this));
 131
 132   if (result.is<TerminalState>()) {
 133     NotifyDecodeComplete(mDecoder->GetImage(), mDecoder);
 134     return;  // We're done.
 135   }
 136
 137   if (result == LexerResult(Yield::NEED_MORE_DATA)) {
 138     // We can't make any more progress right now. We also don't want to report
 139     // any progress, because it's important that metadata decode results are
 140     // delivered atomically. The decoder itself will ensure that we get
 141     // reenqueued when more data is available; just return for now.
 142     return;
 143   }
 144
 145   MOZ_ASSERT_UNREACHABLE("Metadata decode yielded for an unexpected reason");
 146 }
 147
 148 ///////////////////////////////////////////////////////////////////////////////
 149 // AnonymousDecodingTask implementation.
 150 ///////////////////////////////////////////////////////////////////////////////
 151
 152 AnonymousDecodingTask::AnonymousDecodingTask(NotNull<Decoder*> aDecoder,
 153                                              bool aResumable)
 154     : mDecoder(aDecoder), mResumable(aResumable) {}
 155
 156 void AnonymousDecodingTask::Run() {
 157   while (true) {
 158     LexerResult result = mDecoder->Decode(WrapNotNull(this));
 159
 160     if (result.is<TerminalState>()) {
 161       return;  // We're done.
 162     }
 163
 164     if (result == LexerResult(Yield::NEED_MORE_DATA)) {
 165       // We can't make any more progress right now. Let the caller decide how to
 166       // handle it.
 167       return;
 168     }
 169
 170     // Right now we don't do anything special for other kinds of yields, so just
 171     // keep working.
 172     MOZ_ASSERT(result.is<Yield>());
 173   }
 174 }
 175
 176 void AnonymousDecodingTask::Resume() {
 177   // Anonymous decoders normally get all their data at once. We have tests
 178   // where they don't; typically in these situations, the test re-runs them
 179   // manually. However some tests want to verify Resume works, so they will
 180   // explicitly request this behaviour.
 181   if (mResumable) {
 182     RefPtr<AnonymousDecodingTask> self(this);
 183     NS_DispatchToMainThread(
 184         NS_NewRunnableFunction("image::AnonymousDecodingTask::Resume",
 185                                [self]() -> void { self->Run(); }));
 186   }
 187 }
 188
 189 }  // namespace image
 190 }  // namespace mozilla