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   CheckedInt<uint32_t> length = CheckedInt<uint32_t>(aWidth) * aHeight * 4;
  56   if (!length.isValid() || length.value() > INT32_MAX) {
  57     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  58     return nullptr;
  59   }
  60   js::AssertSameCompartment(aGlobal.Context(), aGlobal.Get());
  61   JSObject* data =
  62       Uint8ClampedArray::Create(aGlobal.Context(), length.value(), aRv);
  63   if (aRv.Failed()) {
  64     return nullptr;
  65   }
  66   RefPtr<ImageData> imageData = new ImageData(aWidth, aHeight, *data);
  67   return imageData.forget();
  68 }
  69
  70 // static
  71 already_AddRefed<ImageData> ImageData::Constructor(
  72     const GlobalObject& aGlobal, const Uint8ClampedArray& aData,
  73     const uint32_t aWidth, const Optional<uint32_t>& aHeight,
  74     ErrorResult& aRv) {
  75   Maybe<uint32_t> maybeLength = aData.ProcessData(
  76       [&](const Span<uint8_t>& aData, JS::AutoCheckCannotGC&& nogc) {
  77         return Some(aData.Length());
  78       });
  79   uint32_t length = maybeLength.valueOr(0);
  80   if (length == 0 || length % 4) {
  81     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
  82     return nullptr;
  83   }
  84   length /= 4;
  85   if (aWidth == 0) {
  86     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  87     return nullptr;
  88   }
  89   uint32_t height = length / aWidth;
  90   if (length != aWidth * height ||
  91       (aHeight.WasPassed() && aHeight.Value() != height)) {
  92     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  93     return nullptr;
  94   }
  95   RefPtr<ImageData> imageData = new ImageData(aWidth, height, *aData.Obj());
  96   return imageData.forget();
  97 }
  98
  99 void ImageData::HoldData() { mozilla::HoldJSObjects(this); }
 100
 101 void ImageData::DropData() {
 102   if (mData) {
 103     mozilla::DropJSObjects(this);
 104   }
 105 }
 106
 107 bool ImageData::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
 108                            JS::MutableHandle<JSObject*> aReflector) {
 109   return ImageData_Binding::Wrap(aCx, this, aGivenProto, aReflector);
 110 }
 111
 112 // static
 113 already_AddRefed<ImageData> ImageData::ReadStructuredClone(
 114     JSContext* aCx, nsIGlobalObject* aGlobal,
 115     JSStructuredCloneReader* aReader) {
 116   // Read the information out of the stream.
 117   uint32_t width, height;
 118   JS::Rooted<JS::Value> dataArray(aCx);
 119   if (!JS_ReadUint32Pair(aReader, &width, &height) ||
 120       !JS_ReadTypedArray(aReader, &dataArray)) {
 121     return nullptr;
 122   }
 123   MOZ_ASSERT(dataArray.isObject());
 124
 125   RefPtr<ImageData> imageData =
 126       new ImageData(width, height, dataArray.toObject());
 127   return imageData.forget();
 128 }
 129
 130 bool ImageData::WriteStructuredClone(JSContext* aCx,
 131                                      JSStructuredCloneWriter* aWriter) const {
 132   JS::Rooted<JS::Value> arrayValue(aCx, JS::ObjectValue(*GetDataObject()));
 133   if (!JS_WrapValue(aCx, &arrayValue)) {
 134     return false;
 135   }
 136
 137   return JS_WriteUint32Pair(aWriter, Width(), Height()) &&
 138          JS_WriteTypedArray(aWriter, arrayValue);
 139 }
 140
 141 }  // namespace mozilla::dom