dom/base/nsPropertyTable.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 /**
   8  * nsPropertyTable allows a set of arbitrary key/value pairs to be stored
   9  * for any number of nodes, in a global hashtable rather than on the nodes
  10  * themselves.  Nodes can be any type of object; the hashtable keys are
  11  * nsAtom pointers, and the values are void pointers.
  12  */
  13
  14 #ifndef nsPropertyTable_h_
  15 #define nsPropertyTable_h_
  16
  17 #include "mozilla/MemoryReporting.h"
  18 #include "nscore.h"
  19
  20 class nsAtom;
  21
  22 using NSPropertyFunc = void (*)(void* aObject, nsAtom* aPropertyName,
  23                                 void* aPropertyValue, void* aData);
  24
  25 /**
  26  * Callback type for property destructors.  |aObject| is the object
  27  * the property is being removed for, |aPropertyName| is the property
  28  * being removed, |aPropertyValue| is the value of the property, and |aData|
  29  * is the opaque destructor data that was passed to SetProperty().
  30  **/
  31 using NSPropertyDtorFunc = NSPropertyFunc;
  32 class nsINode;
  33 class nsIFrame;
  34
  35 class nsPropertyOwner {
  36  public:
  37   nsPropertyOwner(const nsPropertyOwner& aOther) = default;
  38
  39   // These are the types of objects that can own properties. No object should
  40   // inherit more then one of these classes.
  41   // To add support for more types just add to this list.
  42   MOZ_IMPLICIT nsPropertyOwner(const nsINode* aObject) : mObject(aObject) {}
  43   MOZ_IMPLICIT nsPropertyOwner(const nsIFrame* aObject) : mObject(aObject) {}
  44
  45   operator const void*() { return mObject; }
  46   const void* get() { return mObject; }
  47
  48  private:
  49   const void* mObject;
  50 };
  51
  52 class nsPropertyTable {
  53  public:
  54   /**
  55    * Get the value of the property |aPropertyName| for node |aObject|.
  56    * |aResult|, if supplied, is filled in with a return status code.
  57    **/
  58   void* GetProperty(const nsPropertyOwner& aObject, const nsAtom* aPropertyName,
  59                     nsresult* aResult = nullptr) {
  60     return GetPropertyInternal(aObject, aPropertyName, false, aResult);
  61   }
  62
  63   /**
  64    * Set the value of the property |aPropertyName| to
  65    * |aPropertyValue| for node |aObject|.  |aDtor| is a destructor for the
  66    * property value to be called if the property is removed.  It can be null
  67    * if no destructor is required.  |aDtorData| is an optional pointer to an
  68    * opaque context to be passed to the property destructor.  Note that the
  69    * destructor is global for each property name regardless of node; it is an
  70    * error to set a given property with a different destructor than was used
  71    * before (this will return NS_ERROR_INVALID_ARG). If |aTransfer| is true
  72    * the property will be transfered to the new table when the property table
  73    * for |aObject| changes (currently the tables for nodes are owned by their
  74    * ownerDocument, so if the ownerDocument for a node changes, its property
  75    * table changes too). If |aTransfer| is false the property will just be
  76    * deleted instead.
  77    */
  78   nsresult SetProperty(const nsPropertyOwner& aObject, nsAtom* aPropertyName,
  79                        void* aPropertyValue, NSPropertyDtorFunc aDtor,
  80                        void* aDtorData, bool aTransfer = false) {
  81     return SetPropertyInternal(aObject, aPropertyName, aPropertyValue, aDtor,
  82                                aDtorData, aTransfer);
  83   }
  84
  85   /**
  86    * Remove the property |aPropertyName| in the global category for object
  87    * |aObject|. The property's destructor function will be called.
  88    */
  89   nsresult RemoveProperty(nsPropertyOwner aObject, const nsAtom* aPropertyName);
  90
  91   /**
  92    * Remove the property |aPropertyName| in the global category for object
  93    * |aObject|, but do not call the property's destructor function.  The
  94    * property value is returned.
  95    */
  96   void* TakeProperty(const nsPropertyOwner& aObject,
  97                      const nsAtom* aPropertyName, nsresult* aStatus = nullptr) {
  98     return GetPropertyInternal(aObject, aPropertyName, true, aStatus);
  99   }
 100
 101   /**
 102    * Removes all of the properties for object |aObject|, calling the destructor
 103    * function for each property.
 104    */
 105   void RemoveAllPropertiesFor(nsPropertyOwner aObject);
 106
 107   /**
 108    * Transfers all properties for object |aObject| that were set with the
 109    * |aTransfer| argument as true to |aTable|. Removes the other properties for
 110    * object |aObject|, calling the destructor function for each property.
 111    * If transfering a property fails, this deletes all the properties for object
 112    * |aObject|.
 113    */
 114   nsresult TransferOrRemoveAllPropertiesFor(nsPropertyOwner aObject,
 115                                             nsPropertyTable& aOtherTable);
 116
 117   /**
 118    * Enumerate the properties for object |aObject|.
 119    * For every property |aCallback| will be called with as arguments |aObject|,
 120    * the property name, the property value and |aData|.
 121    */
 122   void Enumerate(nsPropertyOwner aObject, NSPropertyFunc aCallback,
 123                  void* aData);
 124
 125   /**
 126    * Enumerate all the properties.
 127    * For every property |aCallback| will be called with arguments the owner,
 128    * the property name, the property value and |aData|.
 129    */
 130   void EnumerateAll(NSPropertyFunc aCallback, void* aData);
 131
 132   /**
 133    * Removes all of the properties for all objects in the property table,
 134    * calling the destructor function for each property.
 135    */
 136   void RemoveAllProperties();
 137
 138   nsPropertyTable() : mPropertyList(nullptr) {}
 139   ~nsPropertyTable() { RemoveAllProperties(); }
 140
 141   /**
 142    * Function useable as destructor function for property data that is
 143    * XPCOM objects. The function will call NS_IF_RELASE on the value
 144    * to destroy it.
 145    */
 146   static void SupportsDtorFunc(void* aObject, nsAtom* aPropertyName,
 147                                void* aPropertyValue, void* aData);
 148
 149   class PropertyList;
 150
 151   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 152   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 153
 154  private:
 155   void DestroyPropertyList();
 156   PropertyList* GetPropertyListFor(const nsAtom* aPropertyName) const;
 157   void* GetPropertyInternal(nsPropertyOwner aObject,
 158                             const nsAtom* aPropertyName, bool aRemove,
 159                             nsresult* aStatus);
 160   nsresult SetPropertyInternal(nsPropertyOwner aObject, nsAtom* aPropertyName,
 161                                void* aPropertyValue, NSPropertyDtorFunc aDtor,
 162                                void* aDtorData, bool aTransfer);
 163
 164   PropertyList* mPropertyList;
 165 };
 166 #endif