151 lines
4.3 KiB
C++
151 lines
4.3 KiB
C++
/*
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Copyright (c) 2015, Arvid Norberg
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_ALLOCATING_HANDLER_HPP_INCLUDED
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#define TORRENT_ALLOCATING_HANDLER_HPP_INCLUDED
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#include "libtorrent/config.hpp"
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#include "libtorrent/error_code.hpp"
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#include <type_traits>
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namespace libtorrent { namespace aux
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{
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// this is meant to provide the actual storage for the handler allocator.
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// There's only a single slot, so the allocator is only supposed to be used
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// for handlers where there's only a single outstanding operation at a time,
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// per storage object. For instance, peers only ever have one outstanding
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// read operation at a time, so it can reuse its storage for read handlers.
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template <std::size_t Size>
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struct handler_storage
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{
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#if TORRENT_USE_ASSERTS
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handler_storage()
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: used(false)
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{}
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bool used;
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#else
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handler_storage() {}
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#endif
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typename std::aligned_storage<Size>::type bytes;
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private:
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handler_storage(handler_storage const&);
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};
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struct TORRENT_EXTRA_EXPORT error_handler_interface
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{
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virtual void on_exception(std::exception const&) = 0;
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virtual void on_error(error_code const&) = 0;
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protected:
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~error_handler_interface() {}
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};
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// this class is a wrapper for an asio handler object. Its main purpose
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// is to pass along additional parameters to the asio handler allocator
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// function, as well as providing a distinct type for the handler
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// allocator function to overload on
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template <class Handler, std::size_t Size>
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struct allocating_handler
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{
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allocating_handler(
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Handler h, handler_storage<Size>& s, error_handler_interface& eh)
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: handler(std::move(h))
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, storage(s)
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, error_handler(eh)
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{}
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template <class... A>
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void operator()(A&&... a) const
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{
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#ifdef BOOST_NO_EXCEPTIONS
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handler(std::forward<A>(a)...);
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#else
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try
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{
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handler(std::forward<A>(a)...);
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}
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catch (system_error const& e)
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{
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error_handler.on_error(e.code());
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}
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catch (std::exception const& e)
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{
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error_handler.on_exception(e);
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}
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catch (...)
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{
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// this is pretty bad
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TORRENT_ASSERT(false);
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std::runtime_error e("unknown exception");
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error_handler.on_exception(e);
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}
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#endif
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}
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friend void* asio_handler_allocate(
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std::size_t size, allocating_handler<Handler, Size>* ctx)
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{
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TORRENT_UNUSED(size);
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TORRENT_ASSERT(size <= Size);
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#if TORRENT_USE_ASSERTS
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TORRENT_ASSERT(!ctx->storage.used);
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ctx->storage.used = true;
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#endif
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return &ctx->storage.bytes;
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}
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friend void asio_handler_deallocate(
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void* ptr, std::size_t size, allocating_handler<Handler, Size>* ctx)
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{
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TORRENT_UNUSED(ptr);
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TORRENT_UNUSED(size);
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TORRENT_UNUSED(ctx);
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TORRENT_ASSERT(size <= Size);
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TORRENT_ASSERT(ptr == &ctx->storage.bytes);
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#if TORRENT_USE_ASSERTS
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ctx->storage.used = false;
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#endif
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}
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Handler handler;
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handler_storage<Size>& storage;
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error_handler_interface& error_handler;
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};
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}
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}
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#endif
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