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/*
Copyright (C) 1998-99 Paul Barton-Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __qm_pool_h__
#define __qm_pool_h__
#include <vector>
#include <string>
#include <glibmm/threads.h>
#include "pbd/libpbd_visibility.h"
#include "pbd/ringbuffer.h"
/** A pool of data items that can be allocated, read from and written to
* without system memory allocation or locking.
*/
class LIBPBD_API Pool
{
public:
Pool (std::string name, unsigned long item_size, unsigned long nitems);
virtual ~Pool ();
virtual void *alloc ();
virtual void release (void *);
std::string name() const { return _name; }
guint available() const { return free_list.read_space(); }
guint used() const { return free_list.bufsize() - available(); }
guint total() const { return free_list.bufsize(); }
protected:
RingBuffer<void*> free_list; ///< a list of pointers to free items within block
std::string _name;
private:
void *block; ///< data storage area
#ifndef NDEBUG
unsigned long max_usage;
#endif
};
class LIBPBD_API SingleAllocMultiReleasePool : public Pool
{
public:
SingleAllocMultiReleasePool (std::string name, unsigned long item_size, unsigned long nitems);
~SingleAllocMultiReleasePool ();
virtual void *alloc ();
virtual void release (void *);
private:
Glib::Threads::Mutex m_lock;
};
class LIBPBD_API MultiAllocSingleReleasePool : public Pool
{
public:
MultiAllocSingleReleasePool (std::string name, unsigned long item_size, unsigned long nitems);
~MultiAllocSingleReleasePool ();
virtual void *alloc ();
virtual void release (void *);
private:
Glib::Threads::Mutex m_lock;
};
class LIBPBD_API PerThreadPool;
/** Management of a per-thread pool of data that is allocated by one thread and
* freed by one other thread. Not safe for use when there is more than 1
* reader and 1 writer.
*
* This is basically a wrapper around a thread-local storage instance of a
* ringbuffer, made safe for use in the case where multiple threads allocate
* from the ringbuffer and a single thread "frees" the allocations.
*
* Rather than using locks, each thread has its own ringbuffer (and associated
* data), and so it calls alloc(), passes a pointer to the result of the alloc
* to another thread, which later calls push() to "free" it.
*/
class LIBPBD_API CrossThreadPool : public Pool
{
public:
CrossThreadPool (std::string n, unsigned long isize, unsigned long nitems, PerThreadPool *);
void* alloc ();
void push (void *);
PerThreadPool* parent () const {
return _parent;
}
bool empty ();
guint pending_size() const { return pending.read_space(); }
void flush_pending ();
void flush_pending_with_ev (void*);
private:
RingBuffer<void*> pending;
PerThreadPool* _parent;
};
/** A class to manage per-thread pools of memory. One object of this class is instantiated,
* and then it is used to create per-thread pools for 1 or more threads as required.
*/
class LIBPBD_API PerThreadPool
{
public:
PerThreadPool ();
const Glib::Threads::Private<CrossThreadPool>& key() const { return _key; }
void create_per_thread_pool (std::string name, unsigned long item_size, unsigned long nitems);
CrossThreadPool* per_thread_pool (bool must_exist = true);
bool has_per_thread_pool ();
void set_trash (RingBuffer<CrossThreadPool*>* t);
void add_to_trash (CrossThreadPool *);
private:
Glib::Threads::Private<CrossThreadPool> _key;
std::string _name;
/** mutex to protect either changes to the _trash variable, or writes to the RingBuffer */
Glib::Threads::Mutex _trash_mutex;
RingBuffer<CrossThreadPool*>* _trash;
};
#endif // __qm_pool_h__
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