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- /*
- * 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 <typename T> 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<T>::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 <typename T> Registry<T>* Registry<T>::gHead;
- } // namespace sk_tools
- #endif
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