dom/canvas/ImageData.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 et tw=78: */
   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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/dom/ImageData.h"
   8
   9 #include "mozilla/CheckedInt.h"
  10 #include "mozilla/HoldDropJSObjects.h"
  11 #include "mozilla/dom/ImageDataBinding.h"
  12
  13 #include "jsapi.h"
  14
  15 namespace mozilla {
  16 namespace dom {
  17
  18 NS_IMPL_CYCLE_COLLECTING_ADDREF(ImageData)
  19 NS_IMPL_CYCLE_COLLECTING_RELEASE(ImageData)
  20
  21 NS_IMPL_CYCLE_COLLECTION_CLASS(ImageData)
  22
  23 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ImageData)
  24   NS_INTERFACE_MAP_ENTRY(nsISupports)
  25 NS_INTERFACE_MAP_END
  26
  27 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(ImageData)
  28   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mData)
  29 NS_IMPL_CYCLE_COLLECTION_TRACE_END
  30
  31 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(ImageData)
  32 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  33
  34 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ImageData)
  35   tmp->DropData();
  36 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  37
  38 // static
  39 already_AddRefed<ImageData> ImageData::Constructor(const GlobalObject& aGlobal,
  40                                                    const uint32_t aWidth,
  41                                                    const uint32_t aHeight,
  42                                                    ErrorResult& aRv) {
  43   if (aWidth == 0 || aHeight == 0) {
  44     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  45     return nullptr;
  46   }
  47   CheckedInt<uint32_t> length = CheckedInt<uint32_t>(aWidth) * aHeight * 4;
  48   if (!length.isValid()) {
  49     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  50     return nullptr;
  51   }
  52   js::AssertSameCompartment(aGlobal.Context(), aGlobal.Get());
  53   JSObject* data = Uint8ClampedArray::Create(aGlobal.Context(), length.value());
  54   if (!data) {
  55     aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
  56     return nullptr;
  57   }
  58   RefPtr<ImageData> imageData = new ImageData(aWidth, aHeight, *data);
  59   return imageData.forget();
  60 }
  61
  62 // static
  63 already_AddRefed<ImageData> ImageData::Constructor(
  64     const GlobalObject& aGlobal, const Uint8ClampedArray& aData,
  65     const uint32_t aWidth, const Optional<uint32_t>& aHeight,
  66     ErrorResult& aRv) {
  67   aData.ComputeState();
  68
  69   uint32_t length = aData.Length();
  70   if (length == 0 || length % 4) {
  71     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
  72     return nullptr;
  73   }
  74   length /= 4;
  75   if (aWidth == 0) {
  76     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  77     return nullptr;
  78   }
  79   uint32_t height = length / aWidth;
  80   if (length != aWidth * height ||
  81       (aHeight.WasPassed() && aHeight.Value() != height)) {
  82     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  83     return nullptr;
  84   }
  85   RefPtr<ImageData> imageData = new ImageData(aWidth, height, *aData.Obj());
  86   return imageData.forget();
  87 }
  88
  89 void ImageData::HoldData() { mozilla::HoldJSObjects(this); }
  90
  91 void ImageData::DropData() {
  92   if (mData) {
  93     mData = nullptr;
  94     mozilla::DropJSObjects(this);
  95   }
  96 }
  97
  98 bool ImageData::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
  99                            JS::MutableHandle<JSObject*> aReflector) {
 100   return ImageData_Binding::Wrap(aCx, this, aGivenProto, aReflector);
 101 }
 102
 103 // static
 104 already_AddRefed<ImageData> ImageData::ReadStructuredClone(
 105     JSContext* aCx, nsIGlobalObject* aGlobal,
 106     JSStructuredCloneReader* aReader) {
 107   // Read the information out of the stream.
 108   uint32_t width, height;
 109   JS::Rooted<JS::Value> dataArray(aCx);
 110   if (!JS_ReadUint32Pair(aReader, &width, &height) ||
 111       !JS_ReadTypedArray(aReader, &dataArray)) {
 112     return nullptr;
 113   }
 114   MOZ_ASSERT(dataArray.isObject());
 115
 116   RefPtr<ImageData> imageData =
 117       new ImageData(width, height, dataArray.toObject());
 118   return imageData.forget();
 119 }
 120
 121 bool ImageData::WriteStructuredClone(JSContext* aCx,
 122                                      JSStructuredCloneWriter* aWriter) const {
 123   JS::Rooted<JS::Value> arrayValue(aCx, JS::ObjectValue(*GetDataObject()));
 124   if (!JS_WrapValue(aCx, &arrayValue)) {
 125     return false;
 126   }
 127
 128   return JS_WriteUint32Pair(aWriter, Width(), Height()) &&
 129          JS_WriteTypedArray(aWriter, arrayValue);
 130 }
 131
 132 }  // namespace dom
 133 }  // namespace mozilla