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 "ErrorList.h"
  10 #include "js/StructuredClone.h"
  11 #include "js/Value.h"
  12 #include "jsapi.h"
  13 #include "jsfriendapi.h"
  14 #include "mozilla/CheckedInt.h"
  15 #include "mozilla/ErrorResult.h"
  16 #include "mozilla/HoldDropJSObjects.h"
  17 #include "mozilla/RefPtr.h"
  18 #include "mozilla/dom/BindingDeclarations.h"
  19 #include "mozilla/dom/ImageDataBinding.h"
  20 #include "nsCycleCollectionNoteChild.h"
  21
  22 namespace mozilla::dom {
  23
  24 NS_IMPL_CYCLE_COLLECTING_ADDREF(ImageData)
  25 NS_IMPL_CYCLE_COLLECTING_RELEASE(ImageData)
  26
  27 NS_IMPL_CYCLE_COLLECTION_CLASS(ImageData)
  28
  29 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ImageData)
  30   NS_INTERFACE_MAP_ENTRY(nsISupports)
  31 NS_INTERFACE_MAP_END
  32
  33 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(ImageData)
  34   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mData)
  35 NS_IMPL_CYCLE_COLLECTION_TRACE_END
  36
  37 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(ImageData)
  38 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  39
  40 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ImageData)
  41   tmp->DropData();
  42 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  43
  44 // static
  45 already_AddRefed<ImageData> ImageData::Constructor(const GlobalObject& aGlobal,
  46                                                    const uint32_t aWidth,
  47                                                    const uint32_t aHeight,
  48                                                    ErrorResult& aRv) {
  49   if (aWidth == 0 || aHeight == 0) {
  50     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  51     return nullptr;
  52   }
  53
  54   // Restrict the typed array length to INT32_MAX because that's all we support
  55   // in dom::TypedArray::ComputeState.
  56   CheckedInt<uint32_t> length = CheckedInt<uint32_t>(aWidth) * aHeight * 4;
  57   if (!length.isValid() || length.value() > INT32_MAX) {
  58     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  59     return nullptr;
  60   }
  61   js::AssertSameCompartment(aGlobal.Context(), aGlobal.Get());
  62   JSObject* data = Uint8ClampedArray::Create(aGlobal.Context(), length.value());
  63   if (!data) {
  64     aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
  65     return nullptr;
  66   }
  67   RefPtr<ImageData> imageData = new ImageData(aWidth, aHeight, *data);
  68   return imageData.forget();
  69 }
  70
  71 // static
  72 already_AddRefed<ImageData> ImageData::Constructor(
  73     const GlobalObject& aGlobal, const Uint8ClampedArray& aData,
  74     const uint32_t aWidth, const Optional<uint32_t>& aHeight,
  75     ErrorResult& aRv) {
  76   aData.ComputeState();
  77
  78   uint32_t length = aData.Length();
  79   if (length == 0 || length % 4) {
  80     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
  81     return nullptr;
  82   }
  83   length /= 4;
  84   if (aWidth == 0) {
  85     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  86     return nullptr;
  87   }
  88   uint32_t height = length / aWidth;
  89   if (length != aWidth * height ||
  90       (aHeight.WasPassed() && aHeight.Value() != height)) {
  91     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  92     return nullptr;
  93   }
  94   RefPtr<ImageData> imageData = new ImageData(aWidth, height, *aData.Obj());
  95   return imageData.forget();
  96 }
  97
  98 void ImageData::HoldData() { mozilla::HoldJSObjects(this); }
  99
 100 void ImageData::DropData() {
 101   if (mData) {
 102     mozilla::DropJSObjects(this);
 103   }
 104 }
 105
 106 bool ImageData::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
 107                            JS::MutableHandle<JSObject*> aReflector) {
 108   return ImageData_Binding::Wrap(aCx, this, aGivenProto, aReflector);
 109 }
 110
 111 // static
 112 already_AddRefed<ImageData> ImageData::ReadStructuredClone(
 113     JSContext* aCx, nsIGlobalObject* aGlobal,
 114     JSStructuredCloneReader* aReader) {
 115   // Read the information out of the stream.
 116   uint32_t width, height;
 117   JS::Rooted<JS::Value> dataArray(aCx);
 118   if (!JS_ReadUint32Pair(aReader, &width, &height) ||
 119       !JS_ReadTypedArray(aReader, &dataArray)) {
 120     return nullptr;
 121   }
 122   MOZ_ASSERT(dataArray.isObject());
 123
 124   RefPtr<ImageData> imageData =
 125       new ImageData(width, height, dataArray.toObject());
 126   return imageData.forget();
 127 }
 128
 129 bool ImageData::WriteStructuredClone(JSContext* aCx,
 130                                      JSStructuredCloneWriter* aWriter) const {
 131   JS::Rooted<JS::Value> arrayValue(aCx, JS::ObjectValue(*GetDataObject()));
 132   if (!JS_WrapValue(aCx, &arrayValue)) {
 133     return false;
 134   }
 135
 136   return JS_WriteUint32Pair(aWriter, Width(), Height()) &&
 137          JS_WriteTypedArray(aWriter, arrayValue);
 138 }
 139
 140 }  // namespace mozilla::dom