DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (b6d82b1a6b02)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_DOMSVGLENGTH_H__
#define MOZILLA_DOMSVGLENGTH_H__

#include "DOMSVGLengthList.h"
#include "nsCycleCollectionParticipant.h"
#include "nsDebug.h"
#include "nsTArray.h"
#include "SVGLength.h"
#include "mozilla/Attributes.h"
#include "nsWrapperCache.h"

// We make DOMSVGLength a pseudo-interface to allow us to QI to it in order to
// check that the objects that scripts pass to DOMSVGLengthList methods are our
// *native* length objects.
//
// {A8468350-7F7B-4976-9A7E-3765A1DADF9A}
#define MOZILLA_DOMSVGLENGTH_IID                     \
  {                                                  \
    0xA8468350, 0x7F7B, 0x4976, {                    \
      0x9A, 0x7E, 0x37, 0x65, 0xA1, 0xDA, 0xDF, 0x9A \
    }                                                \
  }

#define MOZ_SVG_LIST_INDEX_BIT_COUNT 22  // supports > 4 million list items

namespace mozilla {

class ErrorResult;

namespace dom {
class SVGElement;

/**
 * Class DOMSVGLength
 *
 * This class creates the DOM objects that wrap internal SVGLength objects that
 * are in an SVGLengthList. It is also used to create the objects returned by
 * SVGSVGElement.createSVGLength().
 *
 * For the DOM wrapper classes for non-list SVGLength, see SVGAnimatedLength.h.
 *
 * See the architecture comment in DOMSVGAnimatedLengthList.h.
 *
 * This class is strongly intertwined with DOMSVGAnimatedLengthList and
 * DOMSVGLengthList. We are a friend of DOMSVGLengthList, and are responsible
 * for nulling out our DOMSVGLengthList's pointer to us when we die, making it
 * a real weak pointer.
 *
 * When objects of this type are in a DOMSVGLengthList they belong to an
 * attribute. While they belong to an attribute, the objects' values come from
 * their corresponding internal SVGLength objects in the internal SVGLengthList
 * objects for the attribute. Getting and setting values of a DOMSVGLength
 * requires reading and writing to its internal SVGLength. However, if the
 * DOMSVGLength is detached from its DOMSVGLengthList then it first makes a
 * copy of its internal SVGLength's value and unit so that it doesn't appear to
 * "lose" its value from script's perspective on being removed from the list.
 * This means that these DOM tearoffs have space to store these values, even
 * though they're not used in the common case.
 *
 * Objects of this type are also used to reflect the baseVal and animVal of
 * a single, non-list SVGLength attribute. Getting and settings values of the
 * DOMSVGLength in this case requires reading and writing to the corresponding
 * SVGAnimatedLength object.
 *
 * This class also stores its current list index, attribute enum, and whether
 * it belongs to a baseVal or animVal list. This is so that objects of this
 * type can find their corresponding internal SVGLength.
 *
 * To use these classes for <length> attributes as well as <list-of-length>
 * attributes, we would need to take a bit from mListIndex and use that to
 * indicate whether the object belongs to a list or non-list attribute, then
 * if-else as appropriate. The bug for doing that work is:
 * https://bugzilla.mozilla.org/show_bug.cgi?id=571734
 */
class DOMSVGLength final : public nsISupports, public nsWrapperCache {
  friend class AutoChangeLengthNotifier;

  /**
   * Ctor for creating the object returned by
   * SVGAnimatedLength::ToDOMBaseVal/ToDOMAnimVal
   */
  DOMSVGLength(SVGAnimatedLength* aVal, dom::SVGElement* aSVGElement,
               bool aAnimVal);

  ~DOMSVGLength();

 public:
  NS_DECLARE_STATIC_IID_ACCESSOR(MOZILLA_DOMSVGLENGTH_IID)
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGLength)

  /**
   * Generic ctor for DOMSVGLength objects that are created for an attribute.
   */
  DOMSVGLength(DOMSVGLengthList* aList, uint8_t aAttrEnum, uint32_t aListIndex,
               bool aIsAnimValItem);

  /**
   * Ctor for creating the objects returned by SVGSVGElement.createSVGLength(),
   * which do not initially belong to an attribute.
   */
  DOMSVGLength();

  static already_AddRefed<DOMSVGLength> GetTearOff(SVGAnimatedLength* aVal,
                                                   dom::SVGElement* aSVGElement,
                                                   bool aAnimVal);

  /**
   * Create an unowned copy of a length that is owned or is reflecting a single
   * attribute. The caller is responsible for the first AddRef().
   */
  DOMSVGLength* Copy();

  bool IsInList() const { return !!mList; }

  /**
   * In future, if this class is used for non-list lengths, this will be
   * different to IsInList().
   */
  bool HasOwner() const { return !!mList; }

  /**
   * Returns whether this length object is reflecting a single SVG element
   * attribute.  This includes the baseVal or animVal of SVGRectElement.x, for
   * example, but not an item in an SVGLengthList, such as those in the
   * baseVal or animVal of SVGTextElement.x.
   */
  bool IsReflectingAttribute() const { return mVal; }

  /**
   * This method is called to notify this DOM object that it is being inserted
   * into a list, and give it the information it needs as a result.
   *
   * This object MUST NOT already belong to a list when this method is called.
   * That's not to say that script can't move these DOM objects between
   * lists - it can - it's just that the logic to handle that (and send out
   * the necessary notifications) is located elsewhere (in DOMSVGLengthList).)
   */
  void InsertingIntoList(DOMSVGLengthList* aList, uint8_t aAttrEnum,
                         uint32_t aListIndex, bool aIsAnimValItem);

  static uint32_t MaxListIndex() {
    return (1U << MOZ_SVG_LIST_INDEX_BIT_COUNT) - 1;
  }

  /// This method is called to notify this object that its list index changed.
  void UpdateListIndex(uint32_t aListIndex) { mListIndex = aListIndex; }

  /**
   * This method is called to notify this DOM object that it is about to be
   * removed from its current DOM list so that it can first make a copy of its
   * internal counterpart's values. (If it didn't do this, then it would
   * "lose" its value on being removed.)
   */
  void RemovingFromList();

  SVGLength ToSVGLength();

  // WebIDL
  uint16_t UnitType();
  float GetValue(ErrorResult& aRv);
  void SetValue(float aUserUnitValue, ErrorResult& aRv);
  float ValueInSpecifiedUnits();
  void SetValueInSpecifiedUnits(float aValue, ErrorResult& aRv);
  void GetValueAsString(nsAString& aValue);
  void SetValueAsString(const nsAString& aValue, ErrorResult& aRv);
  void NewValueSpecifiedUnits(uint16_t aUnit, float aValue, ErrorResult& aRv);
  void ConvertToSpecifiedUnits(uint16_t aUnit, ErrorResult& aRv);

  nsISupports* GetParentObject() const {
    auto svgElement = mList ? Element() : mSVGElement.get();
    return svgElement;
  }

  JSObject* WrapObject(JSContext* aCx,
                       JS::Handle<JSObject*> aGivenProto) override;

 private:
  dom::SVGElement* Element() const { return mList->Element(); }

  uint8_t AttrEnum() const { return mAttrEnum; }

  /**
   * Get the axis that this length lies along. This method must only be called
   * when this object is associated with an element (HasOwner() returns true).
   */
  uint8_t Axis() const { return mList->Axis(); }

  /**
   * Get a reference to the internal SVGLength list item that this DOM wrapper
   * object currently wraps.
   *
   * To simplify the code we just have this one method for obtaining both
   * baseVal and animVal internal items. This means that animVal items don't
   * get const protection, but then our setter methods guard against changing
   * animVal items.
   */
  SVGLength& InternalItem();

#ifdef DEBUG
  bool IndexIsValid();
#endif

  /**
   * Clears soon-to-be-invalid weak references in external objects that were
   * set up during the creation of this object. This should be called during
   * destruction and during cycle collection.
   */
  void CleanupWeakRefs();

  RefPtr<DOMSVGLengthList> mList;

  // Bounds for the following are checked in the ctor, so be sure to update
  // that if you change the capacity of any of the following.

  uint32_t mListIndex : MOZ_SVG_LIST_INDEX_BIT_COUNT;
  uint32_t mAttrEnum : 4;  // supports up to 16 attributes
  uint32_t mIsAnimValItem : 1;

  // The following members are only used when we're not in a list:
  uint32_t mUnit : 5;  // can handle 31 units (the 10 SVG 1.1 units + rem, vw,
                       // vh, wm, calc + future additions)
  float mValue;

  // The following members are only used when we have an SVGAnimatedLength
  SVGAnimatedLength* mVal;  // kept alive because it belongs to mSVGElement
  RefPtr<dom::SVGElement> mSVGElement;
};

NS_DEFINE_STATIC_IID_ACCESSOR(DOMSVGLength, MOZILLA_DOMSVGLENGTH_IID)

}  // namespace dom
}  // namespace mozilla

#undef MOZ_SVG_LIST_INDEX_BIT_COUNT

#endif  // MOZILLA_DOMSVGLENGTH_H__