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 /* Definitions for nsPtrHashKey<T> and nsVoidPtrHashKey.  */
8 
9 #ifndef nsPointerHashKeys_h
10 #define nsPointerHashKeys_h
11 
12 #include "nscore.h"
13 
14 #include "mozilla/Attributes.h"
15 
16 /**
17  * hashkey wrapper using T* KeyType
18  *
19  * @see nsTHashtable::EntryType for specification
20  */
21 template<class T>
22 class nsPtrHashKey : public PLDHashEntryHdr
23 {
24 public:
25   typedef T* KeyType;
26   typedef const T* KeyTypePointer;
27 
nsPtrHashKey(const T * aKey)28   explicit nsPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
nsPtrHashKey(const nsPtrHashKey<T> & aToCopy)29   nsPtrHashKey(const nsPtrHashKey<T>& aToCopy) : mKey(aToCopy.mKey) {}
~nsPtrHashKey()30   ~nsPtrHashKey() {}
31 
GetKey()32   KeyType GetKey() const { return mKey; }
KeyEquals(KeyTypePointer aKey)33   bool KeyEquals(KeyTypePointer aKey) const { return aKey == mKey; }
34 
KeyToPointer(KeyType aKey)35   static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
HashKey(KeyTypePointer aKey)36   static PLDHashNumber HashKey(KeyTypePointer aKey)
37   {
38     return NS_PTR_TO_UINT32(aKey) >> 2;
39   }
40   enum { ALLOW_MEMMOVE = true };
41 
42 protected:
43   T* MOZ_NON_OWNING_REF mKey;
44 };
45 
46 typedef nsPtrHashKey<const void> nsVoidPtrHashKey;
47 
48 #endif // nsPointerHashKeys_h
49