michael@0: 
michael@0: /*
michael@0:  * Copyright 2009 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #ifndef SkTRegistry_DEFINED
michael@0: #define SkTRegistry_DEFINED
michael@0: 
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: /** Template class that registers itself (in the constructor) into a linked-list
michael@0:     and provides a function-pointer. This can be used to auto-register a set of
michael@0:     services, e.g. a set of image codecs.
michael@0:  */
michael@0: template <typename T> class SkTRegistry : SkNoncopyable {
michael@0: public:
michael@0:     typedef T Factory;
michael@0: 
michael@0:     explicit SkTRegistry(T fact) : fFact(fact) {
michael@0: #ifdef SK_BUILD_FOR_ANDROID
michael@0:         // work-around for double-initialization bug
michael@0:         {
michael@0:             SkTRegistry* reg = gHead;
michael@0:             while (reg) {
michael@0:                 if (reg == this) {
michael@0:                     return;
michael@0:                 }
michael@0:                 reg = reg->fChain;
michael@0:             }
michael@0:         }
michael@0: #endif
michael@0:         fChain = gHead;
michael@0:         gHead  = this;
michael@0:     }
michael@0: 
michael@0:     static const SkTRegistry* Head() { return gHead; }
michael@0: 
michael@0:     const SkTRegistry* next() const { return fChain; }
michael@0:     const Factory& factory() const { return fFact; }
michael@0: 
michael@0: private:
michael@0:     Factory      fFact;
michael@0:     SkTRegistry* fChain;
michael@0: 
michael@0:     static SkTRegistry* gHead;
michael@0: };
michael@0: 
michael@0: // The caller still needs to declare an instance of this somewhere
michael@0: template <typename T> SkTRegistry<T>* SkTRegistry<T>::gHead;
michael@0: 
michael@0: #endif