/* * Copyright 2009 The Android Open Source Project * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #ifndef sk_tools_Registry_DEFINED #define sk_tools_Registry_DEFINED #include "include/core/SkTypes.h" #include "include/private/SkNoncopyable.h" namespace sk_tools { /** Template class that registers itself (in the constructor) into a linked-list and provides a function-pointer. This can be used to auto-register a set of services, e.g. a set of image codecs. */ template class Registry : SkNoncopyable { public: explicit Registry(T value) : fValue(value) { #ifdef SK_BUILD_FOR_ANDROID // work-around for double-initialization bug { Registry* reg = gHead; while (reg) { if (reg == this) { return; } reg = reg->fChain; } } #endif fChain = gHead; gHead = this; } static const Registry* Head() { return gHead; } const Registry* next() const { return fChain; } const T& get() const { return fValue; } // for (const T& t : sk_tools::Registry::Range()) { process(t); } struct Range { struct Iterator { const Registry* fPtr; const T& operator*() { return SkASSERT(fPtr), fPtr->get(); } void operator++() { if (fPtr) { fPtr = fPtr->next(); } } bool operator!=(const Iterator& other) const { return fPtr != other.fPtr; } }; Iterator begin() const { return Iterator{Registry::Head()}; } Iterator end() const { return Iterator{nullptr}; } }; private: T fValue; Registry* fChain; static Registry* gHead; }; // The caller still needs to declare an instance of this somewhere template Registry* Registry::gHead; } // namespace sk_tools #endif