dom/smil/SMILTargetIdentifier.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_SMIL_SMILTARGETIDENTIFIER_H_
   8 #define DOM_SMIL_SMILTARGETIDENTIFIER_H_
   9
  10 // XXX Avoid including this here by moving function bodies to the cpp file
  11 #include "nsAtom.h"
  12 #include "nsIContent.h"
  13 #include "mozilla/dom/Element.h"
  14
  15 class nsIContent;
  16
  17 namespace mozilla {
  18 namespace dom {
  19 class Element;
  20 }
  21
  22 /**
  23  * Struct: SMILTargetIdentifier
  24  *
  25  * Tuple of: { Animated Element, Attribute Name }
  26  *
  27  * Used in SMILAnimationController as hash key for mapping an animation
  28  * target to the SMILCompositor for that target.
  29  *
  30  * NOTE: Need a nsRefPtr for the element & attribute name, because
  31  * SMILAnimationController retain its hash table for one sample into the
  32  * future, and we need to make sure their target isn't deleted in that time.
  33  */
  34
  35 struct SMILTargetIdentifier {
  36   SMILTargetIdentifier()
  37       : mElement(nullptr),
  38         mAttributeName(nullptr),
  39         mAttributeNamespaceID(kNameSpaceID_Unknown) {}
  40
  41   inline bool Equals(const SMILTargetIdentifier& aOther) const {
  42     return (aOther.mElement == mElement &&
  43             aOther.mAttributeName == mAttributeName &&
  44             aOther.mAttributeNamespaceID == mAttributeNamespaceID);
  45   }
  46
  47   RefPtr<mozilla::dom::Element> mElement;
  48   RefPtr<nsAtom> mAttributeName;
  49   int32_t mAttributeNamespaceID;
  50 };
  51
  52 /**
  53  * Class: SMILWeakTargetIdentifier
  54  *
  55  * Version of the above struct that uses non-owning pointers.  These are kept
  56  * private, to ensure that they aren't ever dereferenced (or used at all,
  57  * outside of Equals()).
  58  *
  59  * This is solely for comparisons to determine if a target has changed
  60  * from one sample to the next.
  61  */
  62 class SMILWeakTargetIdentifier {
  63  public:
  64   // Trivial constructor
  65   SMILWeakTargetIdentifier() : mElement(nullptr), mAttributeName(nullptr) {}
  66
  67   // Allow us to update a weak identifier to match a given non-weak identifier
  68   SMILWeakTargetIdentifier& operator=(const SMILTargetIdentifier& aOther) {
  69     mElement = aOther.mElement;
  70     mAttributeName = aOther.mAttributeName;
  71     return *this;
  72   }
  73
  74   // Allow for comparison vs. non-weak identifier
  75   inline bool Equals(const SMILTargetIdentifier& aOther) const {
  76     return (aOther.mElement == mElement &&
  77             aOther.mAttributeName == mAttributeName);
  78   }
  79
  80  private:
  81   const nsIContent* mElement;
  82   const nsAtom* mAttributeName;
  83 };
  84
  85 }  // namespace mozilla
  86
  87 #endif  // DOM_SMIL_SMILTARGETIDENTIFIER_H_