+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-/*
- * Ceph - scalable distributed file system
- *
- * Copyright (C) 2014 UnitedStack <haomai@unitedstack.com>
- *
- * Author: Haomai Wang <haomaiwang@gmail.com>
- *
- * This is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License version 2.1, as published by the Free Software
- * Foundation. See file COPYING.
- *
- */
-/* Copyright (c) 2011 Stanford University
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR(S) DISCLAIM ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL AUTHORS BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-#ifndef CEPH_INITIALIZE_H
-#define CEPH_INITIALIZE_H
-
-/**
- * This class is used to manage once-only initialization that should occur
- * before main() is invoked, such as the creation of static variables. It
- * also provides a mechanism for handling dependencies (where one class
- * needs to perform its once-only initialization before another).
- *
- * The simplest way to use an Initialize object is to define a static
- * initialization method for a class, say Foo::init(). Then, declare
- * a static Initialize object in the class:
- * "static Initialize initializer(Foo::init);".
- * The result is that Foo::init will be invoked when the object is
- * constructed (before main() is invoked). Foo::init can create static
- * objects and perform any other once-only initialization needed by the
- * class. Furthermore, if some other class needs to ensure that Foo has
- * been initialized (e.g. as part of its own initialization) it can invoke
- * Foo::init directly (Foo::init should contain an internal guard so that
- * it only performs its functions once, even if invoked several times).
- *
- * There is also a second form of constructor for Initialize that causes a
- * new object to be dynamically allocated and assigned to a pointer, instead
- * of invoking a function. This form allows for the creation of static objects
- * that are never destructed (thereby avoiding issues with the order of
- * destruction).
- */
-class Initialize {
- public:
- /**
- * This form of constructor causes its function argument to be invoked
- * when the object is constructed. When used with a static Initialize
- * object, this will cause \p func to run before main() runs, so that
- * \p func can perform once-only initialization.
- *
- * \param func
- * This function is invoked with no arguments when the object is
- * constructed. Typically the function will create static
- * objects and/or invoke other initialization functions. The
- * function should normally contain an internal guard so that it
- * only performs its initialization the first time it is invoked.
- */
- explicit Initialize(void (*func)()) {
- (*func)();
- }
-
- /**
- * This form of constructor causes a new object of a particular class
- * to be constructed with a no-argument constructor and assigned to a
- * given pointer. This form is typically used with a static Initialize
- * object: the result is that the object will be created and assigned
- * to the pointer before main() runs.
- *
- * \param p
- * Pointer to an object of any type. If the pointer is NULL then
- * it is replaced with a pointer to a newly allocated object of
- * the given type.
- */
- template<typename T>
- explicit Initialize(T*& p) {
- if (p == NULL) {
- p = new T;
- }
- }
-};
-
-#endif // CEPH_INITIALIZE_H
Code Review / stor4nfv.git / blobdiff