lean2/src/util/extensible_object.h

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/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#pragma once
#include <memory>
#include <vector>
#include "util/thread.h"
#include "util/debug.h"
namespace lean {
/**
\brief Template for creating objects that can be attached to "extensions".
*/
template<typename T>
class extensible_object : public T {
public:
class extension {
friend class extensible_object;
extensible_object * m_owner;
public:
extension():m_owner(nullptr) {}
virtual ~extension() {}
extensible_object & get_owner() { return *m_owner; }
};
private:
std::vector<std::unique_ptr<extension>> m_extensions;
public:
template<typename... Args>
extensible_object(Args &&... args):T(std::forward<Args>(args)...) {}
typedef std::unique_ptr<extension> (*mk_extension)();
class extension_factory {
std::vector<mk_extension> m_makers;
mutex m_makers_mutex;
public:
unsigned register_extension(mk_extension mk) {
lock_guard<mutex> lock(m_makers_mutex);
unsigned r = m_makers.size();
m_makers.push_back(mk);
return r;
}
std::unique_ptr<extension> mk(unsigned extid) {
lock_guard<mutex> lock(m_makers_mutex);
return m_makers[extid]();
}
};
static std::unique_ptr<extension_factory> g_extension_factory;
static extension_factory & get_extension_factory() {
if (!g_extension_factory)
g_extension_factory.reset(new extension_factory());
return *g_extension_factory;
}
static unsigned register_extension(mk_extension mk) {
return get_extension_factory().register_extension(mk);
}
extension & get_extension_core(unsigned extid) {
if (extid >= m_extensions.size())
m_extensions.resize(extid+1);
if (!m_extensions[extid]) {
std::unique_ptr<extension> ext = get_extension_factory().mk(extid);
ext->m_owner = this;
m_extensions[extid].swap(ext);
}
return *(m_extensions[extid].get());
}
template<typename Ext> Ext & get_extension(unsigned extid) {
extension & ext = get_extension_core(extid);
lean_assert(dynamic_cast<Ext*>(&ext) != nullptr);
return static_cast<Ext&>(ext);
}
};
template<typename T>
std::unique_ptr<typename extensible_object<T>::extension_factory> extensible_object<T>::g_extension_factory;
}