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_SCRIPT_OBJECTS
  33 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  34
  35 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ImageData)
  36   tmp->DropData();
  37 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  38
  39 //static
  40 already_AddRefed<ImageData>
  41 ImageData::Constructor(const GlobalObject& aGlobal,
  42                        const uint32_t aWidth,
  43                        const uint32_t aHeight,
  44                        ErrorResult& aRv)
  45 {
  46   if (aWidth == 0 || aHeight == 0) {
  47     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  48     return nullptr;
  49   }
  50   CheckedInt<uint32_t> length = CheckedInt<uint32_t>(aWidth) * aHeight * 4;
  51   if (!length.isValid()) {
  52     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  53     return nullptr;
  54   }
  55   js::AssertSameCompartment(aGlobal.Context(), aGlobal.Get());
  56   JSObject* data = Uint8ClampedArray::Create(aGlobal.Context(),
  57                                              length.value());
  58   if (!data) {
  59     aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
  60     return nullptr;
  61   }
  62   nsRefPtr<ImageData> imageData = new ImageData(aWidth, aHeight, *data);
  63   return imageData.forget();
  64 }
  65
  66 //static
  67 already_AddRefed<ImageData>
  68 ImageData::Constructor(const GlobalObject& aGlobal,
  69                        const Uint8ClampedArray& aData,
  70                        const uint32_t aWidth,
  71                        const Optional<uint32_t>& aHeight,
  72                        ErrorResult& aRv)
  73 {
  74   aData.ComputeLengthAndData();
  75
  76   uint32_t length = aData.Length();
  77   if (length == 0 || length % 4) {
  78     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
  79     return nullptr;
  80   }
  81   length /= 4;
  82   if (aWidth == 0) {
  83     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  84     return nullptr;
  85   }
  86   uint32_t height = length / aWidth;
  87   if (length != aWidth * height ||
  88       (aHeight.WasPassed() && aHeight.Value() != height)) {
  89     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
  90     return nullptr;
  91   }
  92   nsRefPtr<ImageData> imageData = new ImageData(aWidth, height, *aData.Obj());
  93   return imageData.forget();
  94 }
  95
  96 void
  97 ImageData::HoldData()
  98 {
  99   mozilla::HoldJSObjects(this);
 100 }
 101
 102 void
 103 ImageData::DropData()
 104 {
 105   if (mData) {
 106     mData = nullptr;
 107     mozilla::DropJSObjects(this);
 108   }
 109 }
 110
 111 JSObject*
 112 ImageData::WrapObject(JSContext* cx)
 113 {
 114   return ImageDataBinding::Wrap(cx, this);
 115 }
 116
 117 } // namespace dom
 118 } // namespace mozilla