125 lines
4.4 KiB
C++
125 lines
4.4 KiB
C++
/*
|
|
|
|
Copyright (c) 2008-2016, Arvid Norberg
|
|
All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions
|
|
are met:
|
|
|
|
* Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
* Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in
|
|
the documentation and/or other materials provided with the distribution.
|
|
* Neither the name of the author nor the names of its
|
|
contributors may be used to endorse or promote products derived
|
|
from this software without specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
*/
|
|
|
|
#ifndef TORRENT_DISK_BUFFER_HOLDER_HPP_INCLUDED
|
|
#define TORRENT_DISK_BUFFER_HOLDER_HPP_INCLUDED
|
|
|
|
#include "libtorrent/config.hpp"
|
|
#include "libtorrent/assert.hpp"
|
|
#include "libtorrent/aux_/block_cache_reference.hpp"
|
|
#include "libtorrent/span.hpp"
|
|
|
|
#include <memory>
|
|
|
|
namespace libtorrent
|
|
{
|
|
struct disk_io_thread;
|
|
struct disk_observer;
|
|
struct disk_buffer_holder;
|
|
|
|
struct TORRENT_EXTRA_EXPORT buffer_allocator_interface
|
|
{
|
|
virtual void free_disk_buffer(char* b) = 0;
|
|
virtual void reclaim_blocks(span<aux::block_cache_reference> refs) = 0;
|
|
virtual disk_buffer_holder allocate_disk_buffer(char const* category) = 0;
|
|
virtual disk_buffer_holder allocate_disk_buffer(bool& exceeded
|
|
, std::shared_ptr<disk_observer> o
|
|
, char const* category) = 0;
|
|
protected:
|
|
~buffer_allocator_interface() {}
|
|
};
|
|
|
|
// The disk buffer holder acts like a ``unique_ptr`` that frees a disk buffer
|
|
// when it's destructed, unless it's released. ``release`` returns the disk
|
|
// buffer and transfers ownership and responsibility to free it to the caller.
|
|
//
|
|
// ``get()`` returns the pointer without transferring ownership. If
|
|
// this buffer has been released, ``get()`` will return nullptr.
|
|
struct TORRENT_EXTRA_EXPORT disk_buffer_holder
|
|
{
|
|
// internal
|
|
disk_buffer_holder(buffer_allocator_interface& alloc, char* buf) noexcept;
|
|
|
|
disk_buffer_holder& operator=(disk_buffer_holder&&) noexcept;
|
|
disk_buffer_holder(disk_buffer_holder&&) noexcept;
|
|
|
|
disk_buffer_holder& operator=(disk_buffer_holder const&) = delete;
|
|
disk_buffer_holder(disk_buffer_holder const&) = delete;
|
|
|
|
// construct a buffer holder that will free the held buffer
|
|
// using a disk buffer pool directly (there's only one
|
|
// disk_buffer_pool per session)
|
|
disk_buffer_holder(buffer_allocator_interface& alloc
|
|
, aux::block_cache_reference const& ref, char* buf) noexcept;
|
|
|
|
// frees any unreleased disk buffer held by this object
|
|
~disk_buffer_holder();
|
|
|
|
// return the held disk buffer and clear it from the
|
|
// holder. The responsibility to free it is passed on
|
|
// to the caller
|
|
char* release() noexcept;
|
|
|
|
// return a pointer to the held buffer
|
|
char* get() const noexcept { return m_buf; }
|
|
|
|
// set the holder object to hold the specified buffer
|
|
// (or nullptr by default). If it's already holding a
|
|
// disk buffer, it will first be freed.
|
|
void reset(char* buf = 0);
|
|
void reset(aux::block_cache_reference const& ref, char* buf);
|
|
|
|
// swap pointers of two disk buffer holders.
|
|
void swap(disk_buffer_holder& h) noexcept
|
|
{
|
|
TORRENT_ASSERT(h.m_allocator == m_allocator);
|
|
std::swap(h.m_buf, m_buf);
|
|
std::swap(h.m_ref, m_ref);
|
|
}
|
|
|
|
aux::block_cache_reference ref() const noexcept { return m_ref; }
|
|
|
|
// implicitly convertible to true if the object is currently holding a
|
|
// buffer
|
|
explicit operator bool() const noexcept { return m_buf != nullptr; }
|
|
|
|
private:
|
|
|
|
buffer_allocator_interface* m_allocator;
|
|
char* m_buf;
|
|
aux::block_cache_reference m_ref;
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|