Ichthyostega
afe07bdb16
obsoleted by C++11 * in most cases, it can be replaced by an explicit conversion operator * especially for the Lumiera Forward Iterators, we need an implicit conversion
112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
/*
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THREAD-LOCAL.hpp - support using thread local data
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Copyright (C) Lumiera.org
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2010, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file thread-local.hpp
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** Helpers for working with thread local data.
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** As we don't want to depend on boost.threads, we'll provide some simple
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** support facilities for dealing with thread local data in RAII fashion.
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** Draft as of 2/10, to be extended on demand.
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**
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** @todo care for unit test coverage
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** @todo WIP-WIP. Maybe add facilities similar to boost::specific_ptr
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**/
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#ifndef LIB_THREAD_LOCAL_H
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#define LIB_THREAD_LOCAL_H
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#include "lib/error.hpp"
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#include <boost/noncopyable.hpp>
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#include <pthread.h>
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namespace lib {
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/**
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* Thread local pointer without ownership management.
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* This (noncopyable) smart-ptr class cares for registering and
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* deregistering the per-instance access key, but besides that
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* behaves passively, like a normal pointer. When first accessed,
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* the pointer is NIL in each new thread; it may be set by assignment.
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*/
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template<typename TAR>
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class ThreadLocalPtr
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: boost::noncopyable
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{
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pthread_key_t key_;
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public:
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ThreadLocalPtr()
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{
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if (pthread_key_create (&key_, NULL))
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throw lumiera::error::External ("unable to create key for thread local data");
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}
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~ThreadLocalPtr()
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{
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WARN_IF (pthread_key_delete (key_), sync, "failure to drop thread-local data key");
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}
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explicit operator bool() const { return isValid(); }
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bool isValid() const { return get(); }
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TAR& operator* () const { return *accessChecked(); }
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TAR* operator-> () const { return accessChecked(); }
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void operator= (TAR& tar) { set(&tar); }
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TAR*
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get() const
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{
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return static_cast<TAR*> (pthread_getspecific (key_));
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}
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void
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set (TAR* pointee)
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{
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if (pthread_setspecific (key_, pointee))
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throw lumiera::error::External ("failed to store thread local data");
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}
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private:
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TAR*
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accessChecked() const
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{
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TAR *p(get());
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if (!p)
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throw lumiera::error::State ("dereferencing a thread local NULL pointer"
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,lumiera::error::LUMIERA_ERROR_BOTTOM_VALUE);
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return p;
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}
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};
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} // namespace lib
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#endif
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