xpcom/glue/nsID.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 nsID_h__
   8 #define nsID_h__
   9
  10 #include <string.h>
  11
  12 #include "nscore.h"
  13
  14 #define NSID_LENGTH 39
  15
  16 /**
  17  * A "unique identifier". This is modeled after OSF DCE UUIDs.
  18  */
  19
  20 struct nsID
  21 {
  22   /**
  23    * @name Identifier values
  24    */
  25
  26   //@{
  27   uint32_t m0;
  28   uint16_t m1;
  29   uint16_t m2;
  30   uint8_t m3[8];
  31   //@}
  32
  33   /**
  34    * @name Methods
  35    */
  36
  37   //@{
  38   /**
  39    * Equivalency method. Compares this nsID with another.
  40    * @return <b>true</b> if they are the same, <b>false</b> if not.
  41    */
  42
  43   inline bool Equals(const nsID& aOther) const
  44   {
  45     // Unfortunately memcmp isn't faster than this.
  46     return
  47       (((uint32_t*)&m0)[0] == ((uint32_t*)&aOther.m0)[0]) &&
  48       (((uint32_t*)&m0)[1] == ((uint32_t*)&aOther.m0)[1]) &&
  49       (((uint32_t*)&m0)[2] == ((uint32_t*)&aOther.m0)[2]) &&
  50       (((uint32_t*)&m0)[3] == ((uint32_t*)&aOther.m0)[3]);
  51   }
  52
  53   inline bool operator==(const nsID& aOther) const
  54   {
  55     return Equals(aOther);
  56   }
  57
  58   /**
  59    * nsID Parsing method. Turns a {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
  60    * string into an nsID
  61    */
  62   bool Parse(const char* aIDStr);
  63
  64 #ifndef XPCOM_GLUE_AVOID_NSPR
  65   /**
  66    * nsID string encoder. Returns an allocated string in
  67    * {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} format. Caller should free string.
  68    * YOU SHOULD ONLY USE THIS IF YOU CANNOT USE ToProvidedString() BELOW.
  69    */
  70   char* ToString() const;
  71
  72   /**
  73    * nsID string encoder. Builds a string in
  74    * {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} format, into a char[NSID_LENGTH]
  75    * buffer provided by the caller (for instance, on the stack).
  76    */
  77   void ToProvidedString(char (&aDest)[NSID_LENGTH]) const;
  78
  79 #endif // XPCOM_GLUE_AVOID_NSPR
  80
  81   //@}
  82 };
  83
  84 /*
  85  * Class IDs
  86  */
  87
  88 typedef nsID nsCID;
  89
  90 // Define an CID
  91 #define NS_DEFINE_CID(_name, _cidspec) \
  92   const nsCID _name = _cidspec
  93
  94 #define NS_DEFINE_NAMED_CID(_name) \
  95   static nsCID k##_name = _name
  96
  97 #define REFNSCID const nsCID&
  98
  99 /**
 100  * An "interface id" which can be used to uniquely identify a given
 101  * interface.
 102  */
 103
 104 typedef nsID nsIID;
 105
 106 /**
 107  * A macro shorthand for <tt>const nsIID&<tt>
 108  */
 109
 110 #define REFNSIID const nsIID&
 111
 112 /**
 113  * Define an IID
 114  * obsolete - do not use this macro
 115  */
 116
 117 #define NS_DEFINE_IID(_name, _iidspec) \
 118   const nsIID _name = _iidspec
 119
 120 /**
 121  * A macro to build the static const IID accessor method. The Dummy
 122  * template parameter only exists so that the kIID symbol will be linked
 123  * properly (weak symbol on linux, gnu_linkonce on mac, multiple-definitions
 124  * merged on windows). Dummy should always be instantiated as "void".
 125  */
 126
 127 #define NS_DECLARE_STATIC_IID_ACCESSOR(the_iid)                         \
 128   template<typename T, typename U>                                      \
 129   struct COMTypeInfo;
 130
 131 #define NS_DEFINE_STATIC_IID_ACCESSOR(the_interface, the_iid)           \
 132   template<typename T>                                                  \
 133   struct the_interface::COMTypeInfo<the_interface, T> {                 \
 134     static const nsIID kIID NS_HIDDEN;                                  \
 135   };                                                                    \
 136   template<typename T>                                                  \
 137   const nsIID the_interface::COMTypeInfo<the_interface, T>::kIID NS_HIDDEN = the_iid;
 138
 139 /**
 140  * A macro to build the static const CID accessor method
 141  */
 142
 143 #define NS_DEFINE_STATIC_CID_ACCESSOR(the_cid) \
 144   static const nsID& GetCID() {static const nsID cid = the_cid; return cid;}
 145
 146 #define NS_GET_IID(T) (T::COMTypeInfo<T, void>::kIID)
 147 #define NS_GET_TEMPLATE_IID(T) (T::template COMTypeInfo<T, void>::kIID)
 148
 149 #endif