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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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