image/imgTools.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 "imgTools.h"
   8
   9 #include "DecodePool.h"
  10 #include "gfxUtils.h"
  11 #include "mozilla/gfx/2D.h"
  12 #include "mozilla/gfx/Logging.h"
  13 #include "mozilla/RefPtr.h"
  14 #include "nsCOMPtr.h"
  15 #include "mozilla/dom/Document.h"
  16 #include "nsError.h"
  17 #include "imgLoader.h"
  18 #include "imgICache.h"
  19 #include "imgIContainer.h"
  20 #include "imgIEncoder.h"
  21 #include "nsComponentManagerUtils.h"
  22 #include "nsNetUtil.h"  // for NS_NewBufferedInputStream
  23 #include "nsStreamUtils.h"
  24 #include "nsStringStream.h"
  25 #include "nsContentUtils.h"
  26 #include "nsProxyRelease.h"
  27 #include "nsIStreamListener.h"
  28 #include "ImageFactory.h"
  29 #include "Image.h"
  30 #include "IProgressObserver.h"
  31 #include "ScriptedNotificationObserver.h"
  32 #include "imgIScriptedNotificationObserver.h"
  33 #include "gfxPlatform.h"
  34 #include "js/ArrayBuffer.h"
  35 #include "js/RootingAPI.h"  // JS::{Handle,Rooted}
  36 #include "js/Value.h"       // JS::Value
  37 #include "Orientation.h"
  38
  39 using namespace mozilla::gfx;
  40
  41 namespace mozilla {
  42 namespace image {
  43
  44 namespace {
  45
  46 static nsresult sniff_mimetype_callback(nsIInputStream* in, void* data,
  47                                         const char* fromRawSegment,
  48                                         uint32_t toOffset, uint32_t count,
  49                                         uint32_t* writeCount) {
  50   nsCString* mimeType = static_cast<nsCString*>(data);
  51   MOZ_ASSERT(mimeType, "mimeType is null!");
  52
  53   if (count > 0) {
  54     imgLoader::GetMimeTypeFromContent(fromRawSegment, count, *mimeType);
  55   }
  56
  57   *writeCount = 0;
  58   return NS_ERROR_FAILURE;
  59 }
  60
  61 class ImageDecoderListener final : public nsIStreamListener,
  62                                    public IProgressObserver,
  63                                    public imgIContainer {
  64  public:
  65   NS_DECL_ISUPPORTS
  66
  67   ImageDecoderListener(nsIURI* aURI, imgIContainerCallback* aCallback,
  68                        imgINotificationObserver* aObserver)
  69       : mURI(aURI),
  70         mImage(nullptr),
  71         mCallback(aCallback),
  72         mObserver(aObserver) {
  73     MOZ_ASSERT(NS_IsMainThread());
  74   }
  75
  76   NS_IMETHOD
  77   OnDataAvailable(nsIRequest* aRequest, nsIInputStream* aInputStream,
  78                   uint64_t aOffset, uint32_t aCount) override {
  79     if (!mImage) {
  80       nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
  81
  82       nsCString mimeType;
  83       channel->GetContentType(mimeType);
  84
  85       if (aInputStream) {
  86         // Look at the first few bytes and see if we can tell what the data is
  87         // from that since servers tend to lie. :(
  88         uint32_t unused;
  89         aInputStream->ReadSegments(sniff_mimetype_callback, &mimeType, aCount,
  90                                    &unused);
  91       }
  92
  93       RefPtr<ProgressTracker> tracker = new ProgressTracker();
  94       if (mObserver) {
  95         tracker->AddObserver(this);
  96       }
  97
  98       mImage = ImageFactory::CreateImage(channel, tracker, mimeType, mURI,
  99                                          /* aIsMultiPart */ false, 0);
 100
 101       if (mImage->HasError()) {
 102         return NS_ERROR_FAILURE;
 103       }
 104     }
 105
 106     return mImage->OnImageDataAvailable(aRequest, nullptr, aInputStream,
 107                                         aOffset, aCount);
 108   }
 109
 110   NS_IMETHOD
 111   OnStartRequest(nsIRequest* aRequest) override { return NS_OK; }
 112
 113   NS_IMETHOD
 114   OnStopRequest(nsIRequest* aRequest, nsresult aStatus) override {
 115     // Encouter a fetch error, or no data could be fetched.
 116     if (!mImage || NS_FAILED(aStatus)) {
 117       mCallback->OnImageReady(nullptr, mImage ? aStatus : NS_ERROR_FAILURE);
 118       return NS_OK;
 119     }
 120
 121     mImage->OnImageDataComplete(aRequest, nullptr, aStatus, true);
 122     nsCOMPtr<imgIContainer> container = this;
 123     mCallback->OnImageReady(container, aStatus);
 124     return NS_OK;
 125   }
 126
 127   virtual void Notify(int32_t aType,
 128                       const nsIntRect* aRect = nullptr) override {
 129     if (mObserver) {
 130       mObserver->Notify(nullptr, aType, aRect);
 131     }
 132   }
 133
 134   virtual void OnLoadComplete(bool aLastPart) override {}
 135
 136   // Other notifications are ignored.
 137   virtual void SetHasImage() override {}
 138   virtual bool NotificationsDeferred() const override { return false; }
 139   virtual void MarkPendingNotify() override {}
 140   virtual void ClearPendingNotify() override {}
 141
 142   // imgIContainer
 143   NS_FORWARD_IMGICONTAINER(mImage->)
 144
 145   nsresult GetNativeSizes(nsTArray<nsIntSize>& aNativeSizes) const override {
 146     return mImage->GetNativeSizes(aNativeSizes);
 147   }
 148
 149   size_t GetNativeSizesLength() const override {
 150     return mImage->GetNativeSizesLength();
 151   }
 152
 153  private:
 154   virtual ~ImageDecoderListener() = default;
 155
 156   nsCOMPtr<nsIURI> mURI;
 157   RefPtr<image::Image> mImage;
 158   nsCOMPtr<imgIContainerCallback> mCallback;
 159   nsCOMPtr<imgINotificationObserver> mObserver;
 160 };
 161
 162 NS_IMPL_ISUPPORTS(ImageDecoderListener, nsIStreamListener, imgIContainer)
 163
 164 class ImageDecoderHelper final : public Runnable,
 165                                  public nsIInputStreamCallback {
 166  public:
 167   NS_DECL_ISUPPORTS_INHERITED
 168
 169   ImageDecoderHelper(already_AddRefed<image::Image> aImage,
 170                      already_AddRefed<nsIInputStream> aInputStream,
 171                      nsIEventTarget* aEventTarget,
 172                      imgIContainerCallback* aCallback,
 173                      nsIEventTarget* aCallbackEventTarget)
 174       : Runnable("ImageDecoderHelper"),
 175         mImage(std::move(aImage)),
 176         mInputStream(std::move(aInputStream)),
 177         mEventTarget(aEventTarget),
 178         mCallback(aCallback),
 179         mCallbackEventTarget(aCallbackEventTarget),
 180         mStatus(NS_OK) {
 181     MOZ_ASSERT(NS_IsMainThread());
 182   }
 183
 184   NS_IMETHOD
 185   Run() override {
 186     // This runnable is dispatched on the Image thread when reading data, but
 187     // at the end, it goes back to the main-thread in order to complete the
 188     // operation.
 189     if (NS_IsMainThread()) {
 190       // Let the Image know we've sent all the data.
 191       mImage->OnImageDataComplete(nullptr, nullptr, mStatus, true);
 192
 193       RefPtr<ProgressTracker> tracker = mImage->GetProgressTracker();
 194       tracker->SyncNotifyProgress(FLAG_LOAD_COMPLETE);
 195
 196       nsCOMPtr<imgIContainer> container;
 197       if (NS_SUCCEEDED(mStatus)) {
 198         container = mImage;
 199       }
 200
 201       mCallback->OnImageReady(container, mStatus);
 202       return NS_OK;
 203     }
 204
 205     uint64_t length;
 206     nsresult rv = mInputStream->Available(&length);
 207     if (rv == NS_BASE_STREAM_CLOSED) {
 208       return OperationCompleted(NS_OK);
 209     }
 210
 211     if (NS_WARN_IF(NS_FAILED(rv))) {
 212       return OperationCompleted(rv);
 213     }
 214
 215     // Nothing else to read, but maybe we just need to wait.
 216     if (length == 0) {
 217       nsCOMPtr<nsIAsyncInputStream> asyncInputStream =
 218           do_QueryInterface(mInputStream);
 219       if (asyncInputStream) {
 220         rv = asyncInputStream->AsyncWait(this, 0, 0, mEventTarget);
 221         if (NS_WARN_IF(NS_FAILED(rv))) {
 222           return OperationCompleted(rv);
 223         }
 224         return NS_OK;
 225       }
 226
 227       // We really have nothing else to read.
 228       if (length == 0) {
 229         return OperationCompleted(NS_OK);
 230       }
 231     }
 232
 233     // Send the source data to the Image.
 234     rv = mImage->OnImageDataAvailable(nullptr, nullptr, mInputStream, 0,
 235                                       uint32_t(length));
 236     if (NS_WARN_IF(NS_FAILED(rv))) {
 237       return OperationCompleted(rv);
 238     }
 239
 240     rv = mEventTarget->Dispatch(this, NS_DISPATCH_NORMAL);
 241     if (NS_WARN_IF(NS_FAILED(rv))) {
 242       return OperationCompleted(rv);
 243     }
 244
 245     return NS_OK;
 246   }
 247
 248   NS_IMETHOD
 249   OnInputStreamReady(nsIAsyncInputStream* aAsyncInputStream) override {
 250     MOZ_ASSERT(!NS_IsMainThread());
 251     return Run();
 252   }
 253
 254   nsresult OperationCompleted(nsresult aStatus) {
 255     MOZ_ASSERT(!NS_IsMainThread());
 256
 257     mStatus = aStatus;
 258     mCallbackEventTarget->Dispatch(this, NS_DISPATCH_NORMAL);
 259     return NS_OK;
 260   }
 261
 262  private:
 263   ~ImageDecoderHelper() {
 264     SurfaceCache::ReleaseImageOnMainThread(mImage.forget());
 265     NS_ReleaseOnMainThread("ImageDecoderHelper::mCallback", mCallback.forget());
 266   }
 267
 268   RefPtr<image::Image> mImage;
 269
 270   nsCOMPtr<nsIInputStream> mInputStream;
 271   nsCOMPtr<nsIEventTarget> mEventTarget;
 272   nsCOMPtr<imgIContainerCallback> mCallback;
 273   nsCOMPtr<nsIEventTarget> mCallbackEventTarget;
 274
 275   nsresult mStatus;
 276 };
 277
 278 NS_IMPL_ISUPPORTS_INHERITED(ImageDecoderHelper, Runnable,
 279                             nsIInputStreamCallback)
 280
 281 }  // namespace
 282
 283 /* ========== imgITools implementation ========== */
 284
 285 NS_IMPL_ISUPPORTS(imgTools, imgITools)
 286
 287 imgTools::imgTools() { /* member initializers and constructor code */
 288 }
 289
 290 imgTools::~imgTools() { /* destructor code */
 291 }
 292
 293 NS_IMETHODIMP
 294 imgTools::DecodeImageFromArrayBuffer(JS::Handle<JS::Value> aArrayBuffer,
 295                                      const nsACString& aMimeType,
 296                                      JSContext* aCx,
 297                                      imgIContainer** aContainer) {
 298   if (!aArrayBuffer.isObject()) {
 299     return NS_ERROR_FAILURE;
 300   }
 301
 302   JS::Rooted<JSObject*> obj(aCx,
 303                             JS::UnwrapArrayBuffer(&aArrayBuffer.toObject()));
 304   if (!obj) {
 305     return NS_ERROR_FAILURE;
 306   }
 307
 308   uint8_t* bufferData = nullptr;
 309   uint32_t bufferLength = 0;
 310   bool isSharedMemory = false;
 311
 312   JS::GetArrayBufferLengthAndData(obj, &bufferLength, &isSharedMemory,
 313                                   &bufferData);
 314   return DecodeImageFromBuffer((char*)bufferData, bufferLength, aMimeType,
 315                                aContainer);
 316 }
 317
 318 NS_IMETHODIMP
 319 imgTools::DecodeImageFromBuffer(const char* aBuffer, uint32_t aSize,
 320                                 const nsACString& aMimeType,
 321                                 imgIContainer** aContainer) {
 322   MOZ_ASSERT(NS_IsMainThread());
 323
 324   NS_ENSURE_ARG_POINTER(aBuffer);
 325
 326   // Create a new image container to hold the decoded data.
 327   nsAutoCString mimeType(aMimeType);
 328   RefPtr<image::Image> image =
 329       ImageFactory::CreateAnonymousImage(mimeType, aSize);
 330   RefPtr<ProgressTracker> tracker = image->GetProgressTracker();
 331
 332   if (image->HasError()) {
 333     return NS_ERROR_FAILURE;
 334   }
 335
 336   // Let's create a temporary inputStream.
 337   nsCOMPtr<nsIInputStream> stream;
 338   nsresult rv = NS_NewByteInputStream(
 339       getter_AddRefs(stream), Span(aBuffer, aSize), NS_ASSIGNMENT_DEPEND);
 340   NS_ENSURE_SUCCESS(rv, rv);
 341   MOZ_ASSERT(stream);
 342   MOZ_ASSERT(NS_InputStreamIsBuffered(stream));
 343
 344   rv = image->OnImageDataAvailable(nullptr, nullptr, stream, 0, aSize);
 345   NS_ENSURE_SUCCESS(rv, rv);
 346
 347   // Let the Image know we've sent all the data.
 348   rv = image->OnImageDataComplete(nullptr, nullptr, NS_OK, true);
 349   tracker->SyncNotifyProgress(FLAG_LOAD_COMPLETE);
 350   NS_ENSURE_SUCCESS(rv, rv);
 351
 352   // All done.
 353   image.forget(aContainer);
 354   return NS_OK;
 355 }
 356
 357 NS_IMETHODIMP
 358 imgTools::DecodeImageFromChannelAsync(nsIURI* aURI, nsIChannel* aChannel,
 359                                       imgIContainerCallback* aCallback,
 360                                       imgINotificationObserver* aObserver) {
 361   MOZ_ASSERT(NS_IsMainThread());
 362
 363   NS_ENSURE_ARG_POINTER(aURI);
 364   NS_ENSURE_ARG_POINTER(aChannel);
 365   NS_ENSURE_ARG_POINTER(aCallback);
 366
 367   RefPtr<ImageDecoderListener> listener =
 368       new ImageDecoderListener(aURI, aCallback, aObserver);
 369
 370   return aChannel->AsyncOpen(listener);
 371 }
 372
 373 NS_IMETHODIMP
 374 imgTools::DecodeImageAsync(nsIInputStream* aInStr, const nsACString& aMimeType,
 375                            imgIContainerCallback* aCallback,
 376                            nsIEventTarget* aEventTarget) {
 377   MOZ_ASSERT(NS_IsMainThread());
 378
 379   NS_ENSURE_ARG_POINTER(aInStr);
 380   NS_ENSURE_ARG_POINTER(aCallback);
 381   NS_ENSURE_ARG_POINTER(aEventTarget);
 382
 383   nsresult rv;
 384
 385   // Let's continuing the reading on a separate thread.
 386   DecodePool* decodePool = DecodePool::Singleton();
 387   MOZ_ASSERT(decodePool);
 388
 389   RefPtr<nsIEventTarget> target = decodePool->GetIOEventTarget();
 390   NS_ENSURE_TRUE(target, NS_ERROR_FAILURE);
 391
 392   // Prepare the input stream.
 393   nsCOMPtr<nsIInputStream> stream = aInStr;
 394   if (!NS_InputStreamIsBuffered(aInStr)) {
 395     nsCOMPtr<nsIInputStream> bufStream;
 396     rv = NS_NewBufferedInputStream(getter_AddRefs(bufStream), stream.forget(),
 397                                    1024);
 398     NS_ENSURE_SUCCESS(rv, rv);
 399     stream = std::move(bufStream);
 400   }
 401
 402   // Create a new image container to hold the decoded data.
 403   nsAutoCString mimeType(aMimeType);
 404   RefPtr<image::Image> image = ImageFactory::CreateAnonymousImage(mimeType, 0);
 405
 406   // Already an error?
 407   if (image->HasError()) {
 408     return NS_ERROR_FAILURE;
 409   }
 410
 411   RefPtr<ImageDecoderHelper> helper = new ImageDecoderHelper(
 412       image.forget(), stream.forget(), target, aCallback, aEventTarget);
 413   rv = target->Dispatch(helper.forget(), NS_DISPATCH_NORMAL);
 414   NS_ENSURE_SUCCESS(rv, rv);
 415
 416   return NS_OK;
 417 }
 418
 419 /**
 420  * This takes a DataSourceSurface rather than a SourceSurface because some
 421  * of the callers have a DataSourceSurface and we don't want to call
 422  * GetDataSurface on such surfaces since that may incur a conversion to
 423  * SurfaceType::DATA which we don't need.
 424  */
 425 static nsresult EncodeImageData(DataSourceSurface* aDataSurface,
 426                                 DataSourceSurface::ScopedMap& aMap,
 427                                 const nsACString& aMimeType,
 428                                 const nsAString& aOutputOptions,
 429                                 nsIInputStream** aStream) {
 430   MOZ_ASSERT(aDataSurface->GetFormat() == SurfaceFormat::B8G8R8A8 ||
 431                  aDataSurface->GetFormat() == SurfaceFormat::B8G8R8X8,
 432              "We're assuming B8G8R8A8/X8");
 433
 434   // Get an image encoder for the media type
 435   nsAutoCString encoderCID("@mozilla.org/image/encoder;2?type="_ns + aMimeType);
 436
 437   nsCOMPtr<imgIEncoder> encoder = do_CreateInstance(encoderCID.get());
 438   if (!encoder) {
 439     return NS_IMAGELIB_ERROR_NO_ENCODER;
 440   }
 441
 442   IntSize size = aDataSurface->GetSize();
 443   uint32_t dataLength = aMap.GetStride() * size.height;
 444
 445   // Encode the bitmap
 446   nsresult rv = encoder->InitFromData(
 447       aMap.GetData(), dataLength, size.width, size.height, aMap.GetStride(),
 448       imgIEncoder::INPUT_FORMAT_HOSTARGB, aOutputOptions);
 449   NS_ENSURE_SUCCESS(rv, rv);
 450
 451   encoder.forget(aStream);
 452   return NS_OK;
 453 }
 454
 455 static nsresult EncodeImageData(DataSourceSurface* aDataSurface,
 456                                 const nsACString& aMimeType,
 457                                 const nsAString& aOutputOptions,
 458                                 nsIInputStream** aStream) {
 459   DataSourceSurface::ScopedMap map(aDataSurface, DataSourceSurface::READ);
 460   if (!map.IsMapped()) {
 461     return NS_ERROR_FAILURE;
 462   }
 463
 464   return EncodeImageData(aDataSurface, map, aMimeType, aOutputOptions, aStream);
 465 }
 466
 467 NS_IMETHODIMP
 468 imgTools::EncodeImage(imgIContainer* aContainer, const nsACString& aMimeType,
 469                       const nsAString& aOutputOptions,
 470                       nsIInputStream** aStream) {
 471   // Use frame 0 from the image container.
 472   RefPtr<SourceSurface> frame = aContainer->GetFrame(
 473       imgIContainer::FRAME_FIRST,
 474       imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
 475   NS_ENSURE_TRUE(frame, NS_ERROR_FAILURE);
 476
 477   RefPtr<DataSourceSurface> dataSurface;
 478
 479   if (frame->GetFormat() == SurfaceFormat::B8G8R8A8 ||
 480       frame->GetFormat() == SurfaceFormat::B8G8R8X8) {
 481     dataSurface = frame->GetDataSurface();
 482   } else {
 483     // Convert format to SurfaceFormat::B8G8R8A8
 484     dataSurface = gfxUtils::CopySurfaceToDataSourceSurfaceWithFormat(
 485         frame, SurfaceFormat::B8G8R8A8);
 486   }
 487
 488   NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
 489
 490   return EncodeImageData(dataSurface, aMimeType, aOutputOptions, aStream);
 491 }
 492
 493 NS_IMETHODIMP
 494 imgTools::EncodeScaledImage(imgIContainer* aContainer,
 495                             const nsACString& aMimeType, int32_t aScaledWidth,
 496                             int32_t aScaledHeight,
 497                             const nsAString& aOutputOptions,
 498                             nsIInputStream** aStream) {
 499   NS_ENSURE_ARG(aScaledWidth >= 0 && aScaledHeight >= 0);
 500
 501   // If no scaled size is specified, we'll just encode the image at its
 502   // original size (no scaling).
 503   if (aScaledWidth == 0 && aScaledHeight == 0) {
 504     return EncodeImage(aContainer, aMimeType, aOutputOptions, aStream);
 505   }
 506
 507   // Retrieve the image's size.
 508   int32_t imageWidth = 0;
 509   int32_t imageHeight = 0;
 510   aContainer->GetWidth(&imageWidth);
 511   aContainer->GetHeight(&imageHeight);
 512
 513   // If the given width or height is zero we'll replace it with the image's
 514   // original dimensions.
 515   IntSize scaledSize(aScaledWidth == 0 ? imageWidth : aScaledWidth,
 516                      aScaledHeight == 0 ? imageHeight : aScaledHeight);
 517
 518   // Use frame 0 from the image container.
 519   RefPtr<SourceSurface> frame = aContainer->GetFrameAtSize(
 520       scaledSize, imgIContainer::FRAME_FIRST,
 521       imgIContainer::FLAG_HIGH_QUALITY_SCALING |
 522           imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
 523   NS_ENSURE_TRUE(frame, NS_ERROR_FAILURE);
 524
 525   // If the given surface is the right size/format, we can encode it directly.
 526   if (scaledSize == frame->GetSize() &&
 527       (frame->GetFormat() == SurfaceFormat::B8G8R8A8 ||
 528        frame->GetFormat() == SurfaceFormat::B8G8R8X8)) {
 529     RefPtr<DataSourceSurface> dataSurface = frame->GetDataSurface();
 530     if (dataSurface) {
 531       return EncodeImageData(dataSurface, aMimeType, aOutputOptions, aStream);
 532     }
 533   }
 534
 535   // Otherwise we need to scale it using a draw target.
 536   RefPtr<DataSourceSurface> dataSurface =
 537       Factory::CreateDataSourceSurface(scaledSize, SurfaceFormat::B8G8R8A8);
 538   if (NS_WARN_IF(!dataSurface)) {
 539     return NS_ERROR_FAILURE;
 540   }
 541
 542   DataSourceSurface::ScopedMap map(dataSurface, DataSourceSurface::READ_WRITE);
 543   if (!map.IsMapped()) {
 544     return NS_ERROR_FAILURE;
 545   }
 546
 547   RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(
 548       BackendType::SKIA, map.GetData(), dataSurface->GetSize(), map.GetStride(),
 549       SurfaceFormat::B8G8R8A8);
 550   if (!dt) {
 551     gfxWarning() << "imgTools::EncodeImage failed in CreateDrawTargetForData";
 552     return NS_ERROR_OUT_OF_MEMORY;
 553   }
 554
 555   IntSize frameSize = frame->GetSize();
 556   dt->DrawSurface(frame, Rect(0, 0, scaledSize.width, scaledSize.height),
 557                   Rect(0, 0, frameSize.width, frameSize.height),
 558                   DrawSurfaceOptions(),
 559                   DrawOptions(1.0f, CompositionOp::OP_SOURCE));
 560
 561   return EncodeImageData(dataSurface, map, aMimeType, aOutputOptions, aStream);
 562 }
 563
 564 NS_IMETHODIMP
 565 imgTools::EncodeCroppedImage(imgIContainer* aContainer,
 566                              const nsACString& aMimeType, int32_t aOffsetX,
 567                              int32_t aOffsetY, int32_t aWidth, int32_t aHeight,
 568                              const nsAString& aOutputOptions,
 569                              nsIInputStream** aStream) {
 570   NS_ENSURE_ARG(aOffsetX >= 0 && aOffsetY >= 0 && aWidth >= 0 && aHeight >= 0);
 571
 572   // Offsets must be zero when no width and height are given or else we're out
 573   // of bounds.
 574   NS_ENSURE_ARG(aWidth + aHeight > 0 || aOffsetX + aOffsetY == 0);
 575
 576   // If no size is specified then we'll preserve the image's original dimensions
 577   // and don't need to crop.
 578   if (aWidth == 0 && aHeight == 0) {
 579     return EncodeImage(aContainer, aMimeType, aOutputOptions, aStream);
 580   }
 581
 582   // Use frame 0 from the image container.
 583   RefPtr<SourceSurface> frame = aContainer->GetFrame(
 584       imgIContainer::FRAME_FIRST,
 585       imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
 586   NS_ENSURE_TRUE(frame, NS_ERROR_FAILURE);
 587
 588   int32_t frameWidth = frame->GetSize().width;
 589   int32_t frameHeight = frame->GetSize().height;
 590
 591   // If the given width or height is zero we'll replace it with the image's
 592   // original dimensions.
 593   if (aWidth == 0) {
 594     aWidth = frameWidth;
 595   } else if (aHeight == 0) {
 596     aHeight = frameHeight;
 597   }
 598
 599   // Check that the given crop rectangle is within image bounds.
 600   NS_ENSURE_ARG(frameWidth >= aOffsetX + aWidth &&
 601                 frameHeight >= aOffsetY + aHeight);
 602
 603   RefPtr<DataSourceSurface> dataSurface = Factory::CreateDataSourceSurface(
 604       IntSize(aWidth, aHeight), SurfaceFormat::B8G8R8A8,
 605       /* aZero = */ true);
 606   if (NS_WARN_IF(!dataSurface)) {
 607     return NS_ERROR_FAILURE;
 608   }
 609
 610   DataSourceSurface::ScopedMap map(dataSurface, DataSourceSurface::READ_WRITE);
 611   if (!map.IsMapped()) {
 612     return NS_ERROR_FAILURE;
 613   }
 614
 615   RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(
 616       BackendType::SKIA, map.GetData(), dataSurface->GetSize(), map.GetStride(),
 617       SurfaceFormat::B8G8R8A8);
 618   if (!dt) {
 619     gfxWarning()
 620         << "imgTools::EncodeCroppedImage failed in CreateDrawTargetForData";
 621     return NS_ERROR_OUT_OF_MEMORY;
 622   }
 623   dt->CopySurface(frame, IntRect(aOffsetX, aOffsetY, aWidth, aHeight),
 624                   IntPoint(0, 0));
 625
 626   return EncodeImageData(dataSurface, map, aMimeType, aOutputOptions, aStream);
 627 }
 628
 629 NS_IMETHODIMP
 630 imgTools::CreateScriptedObserver(imgIScriptedNotificationObserver* aInner,
 631                                  imgINotificationObserver** aObserver) {
 632   NS_ADDREF(*aObserver = new ScriptedNotificationObserver(aInner));
 633   return NS_OK;
 634 }
 635
 636 NS_IMETHODIMP
 637 imgTools::GetImgLoaderForDocument(dom::Document* aDoc, imgILoader** aLoader) {
 638   NS_IF_ADDREF(*aLoader = nsContentUtils::GetImgLoaderForDocument(aDoc));
 639   return NS_OK;
 640 }
 641
 642 NS_IMETHODIMP
 643 imgTools::GetImgCacheForDocument(dom::Document* aDoc, imgICache** aCache) {
 644   nsCOMPtr<imgILoader> loader;
 645   nsresult rv = GetImgLoaderForDocument(aDoc, getter_AddRefs(loader));
 646   NS_ENSURE_SUCCESS(rv, rv);
 647   return CallQueryInterface(loader, aCache);
 648 }
 649
 650 }  // namespace image
 651 }  // namespace mozilla