request.h

/***************************************************************************
 * include/stxxl/bits/io/request.h
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 * Copyright (C) 2008 Andreas Beckmann <[email protected]>
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/

#ifndef STXXL_IO__REQUEST_H_
#define STXXL_IO__REQUEST_H_

#include <cassert>

#include <stxxl/bits/namespace.h>
#include <stxxl/bits/io/request_interface.h>
#include <stxxl/bits/common/mutex.h>
#include <stxxl/bits/common/exceptions.h>
#include <stxxl/bits/io/completion_handler.h>
#include <stxxl/bits/compat_unique_ptr.h>
#include <stxxl/bits/verbose.h>


__STXXL_BEGIN_NAMESPACE


#define BLOCK_ALIGN 4096

class file;
class request_ptr;

class request : virtual public request_interface
{
 friend class request_ptr;

protected:
 completion_handler on_complete;
 int ref_cnt;
 compat_unique_ptr<stxxl::io_error>::result error;

 mutex ref_cnt_mutex;

protected:
 file * file_;
 void * buffer;
 offset_type offset;
 size_type bytes;
 request_type type;

 void completed();

public:
 // returns number of references
 int nref()
 {
 scoped_mutex_lock Lock(ref_cnt_mutex);
 return ref_cnt;
 }

 request(const completion_handler & on_compl,
 file * file__,
 void * buffer_,
 offset_type offset_,
 size_type bytes_,
 request_type type_);

 virtual ~request();

 file * get_file() const { return file_; }
 void * get_buffer() const { return buffer; }
 offset_type get_offset() const { return offset; }
 size_type get_size() const { return bytes; }
 request_type get_type() const { return type; }

 void check_alignment() const;

 std::ostream & print(std::ostream & out) const;

 void error_occured(const char * msg)
 {
 error.reset(new stxxl::io_error(msg));
 }

 void error_occured(const std::string & msg)
 {
 error.reset(new stxxl::io_error(msg));
 }

 void check_errors() throw (stxxl::io_error)
 {
 if (error.get())
 throw *(error.get());
 }

private:
 void add_ref()
 {
 scoped_mutex_lock Lock(ref_cnt_mutex);
 ref_cnt++;
 STXXL_VERBOSE3("[" << static_cast<void *>(this) << "] request::add_ref(): added reference, ref_cnt=" << ref_cnt);
 }

 bool sub_ref()
 {
 int val;
 {
 scoped_mutex_lock Lock(ref_cnt_mutex);
 val = --ref_cnt;
 STXXL_VERBOSE3("[" << static_cast<void *>(this) << "] request::sub_ref(): subtracted reference, ref_cnt=" << ref_cnt);
 }
 assert(val >= 0);
 return (val == 0);
 }

protected:
 void check_nref(bool after = false)
 {
 if (nref() < 2)
 check_nref_failed(after);
 }

private:
 void check_nref_failed(bool after);
};

inline std::ostream & operator << (std::ostream & out, const request & req)
{
 return req.print(out);
}


__STXXL_END_NAMESPACE

#endif // !STXXL_IO__REQUEST_H_
// vim: et:ts=4:sw=4