From 6014ac1e7aff4d2ca8871b5c2dcbf21efdd54ca8 Mon Sep 17 00:00:00 2001
From: Daniel Wallin <daniel-w@users.noreply.github.com>
Date: Wed, 20 May 2009 08:57:08 +0000
Subject: [PATCH] Allocate memory for read/write handlers inplace inside
 peer_connection instance.

---
 include/libtorrent/config.hpp          |  7 +++
 include/libtorrent/peer_connection.hpp | 85 ++++++++++++++++++++++++++
 src/peer_connection.cpp                | 18 ++++--
 3 files changed, 105 insertions(+), 5 deletions(-)

diff --git a/include/libtorrent/config.hpp b/include/libtorrent/config.hpp
index f6f017ddc..dac9136f6 100644
--- a/include/libtorrent/config.hpp
+++ b/include/libtorrent/config.hpp
@@ -138,6 +138,13 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_USE_LOCALE_FILENAMES 0
 #endif
 
+#if !defined(TORRENT_READ_HANDLER_MAX_SIZE)
+# define TORRENT_READ_HANDLER_MAX_SIZE 100
+#endif
+
+#if !defined(TORRENT_WRITE_HANDLER_MAX_SIZE)
+# define TORRENT_WRITE_HANDLER_MAX_SIZE 100
+#endif
 
 #endif // TORRENT_CONFIG_HPP_INCLUDED
 
diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index d9df58c0f..d87042e4e 100644
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -985,6 +985,91 @@ namespace libtorrent
 		// pick any pieces from this peer
 		bool m_no_download:1;
 		
+		template <std::size_t Size>
+		struct handler_storage
+		{
+#ifdef TORRENT_DEBUG
+			handler_storage()
+			  : used(false)
+			{}
+
+			bool used;
+#endif
+			boost::aligned_storage<Size> bytes;
+		};
+
+		handler_storage<TORRENT_READ_HANDLER_MAX_SIZE> m_read_handler_storage;
+		handler_storage<TORRENT_WRITE_HANDLER_MAX_SIZE> m_write_handler_storage;
+
+		template <class Handler, std::size_t Size>
+		struct allocating_handler
+		{
+			allocating_handler(
+				Handler const& handler, handler_storage<Size>& storage
+			)
+			  : handler(handler)
+			  , storage(storage)
+			{}
+
+			template <class A0>
+			void operator()(A0 const& a0) const
+			{
+				handler(a0);
+			}
+
+			template <class A0, class A1>
+			void operator()(A0 const& a0, A1 const& a1) const
+			{
+				handler(a0, a1);
+			}
+
+			template <class A0, class A1, class A2>
+			void operator()(A0 const& a0, A1 const& a1, A2 const& a2) const
+			{
+				handler(a0, a1, a2);
+			}
+
+			friend void* asio_handler_allocate(
+			    std::size_t size, allocating_handler<Handler, Size>* ctx)
+			{
+				assert(size <= Size);
+#ifdef TORRENT_DEBUG
+				assert(!ctx->storage.used);
+				ctx->storage.used = true;
+#endif
+				return &ctx->storage.bytes;
+			}
+
+			friend void asio_handler_deallocate(
+				void*, std::size_t, allocating_handler<Handler, Size>* ctx)
+			{
+#ifdef TORRENT_DEBUG
+				ctx->storage.used = false;
+#endif
+			}
+
+			Handler handler;
+			handler_storage<Size>& storage;
+		};
+
+		template <class Handler>
+		allocating_handler<Handler, TORRENT_READ_HANDLER_MAX_SIZE>
+			make_read_handler(Handler const& handler)
+		{
+			return allocating_handler<Handler, TORRENT_READ_HANDLER_MAX_SIZE>(
+				handler, m_read_handler_storage
+			);
+		}
+
+		template <class Handler>
+		allocating_handler<Handler, TORRENT_WRITE_HANDLER_MAX_SIZE>
+			make_write_handler(Handler const& handler)
+		{
+			return allocating_handler<Handler, TORRENT_WRITE_HANDLER_MAX_SIZE>(
+				handler, m_write_handler_storage
+			);
+		}
+
 #ifdef TORRENT_DEBUG
 	public:
 		bool m_in_constructor:1;
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 664743567..271ef2b60 100644
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -3680,7 +3680,9 @@ namespace libtorrent
 			(*m_logger) << time_now_string() << " *** ASYNC_WRITE [ bytes: " << amount_to_send << " ]\n";
 #endif
 			std::list<asio::const_buffer> const& vec = m_send_buffer.build_iovec(amount_to_send);
-			m_socket->async_write_some(vec, bind(&peer_connection::on_send_data, self(), _1, _2));
+			m_socket->async_write_some(
+				vec, make_write_handler(bind(
+					&peer_connection::on_send_data, self(), _1, _2)));
 
 			m_channel_state[upload_channel] = peer_info::bw_network;
 		}
@@ -3763,7 +3765,10 @@ namespace libtorrent
 			// only receive into regular buffer
 			TORRENT_ASSERT(m_recv_pos + max_receive <= int(m_recv_buffer.size()));
 			m_socket->async_read_some(asio::buffer(&m_recv_buffer[m_recv_pos]
-				, max_receive), bind(&peer_connection::on_receive_data, self(), _1, _2));
+				, max_receive)
+				, make_read_handler(
+					bind(&peer_connection::on_receive_data, self(), _1, _2)
+				));
 		}
 		else if (m_recv_pos >= regular_buffer_size)
 		{
@@ -3772,7 +3777,9 @@ namespace libtorrent
 			TORRENT_ASSERT(m_recv_pos - regular_buffer_size + max_receive <= m_disk_recv_buffer_size);
 			m_socket->async_read_some(asio::buffer(m_disk_recv_buffer.get() + m_recv_pos - regular_buffer_size
 				, max_receive)
-				, bind(&peer_connection::on_receive_data, self(), _1, _2));
+				, make_read_handler(
+					bind(&peer_connection::on_receive_data, self(), _1, _2)
+				));
 		}
 		else
 		{
@@ -3787,8 +3794,9 @@ namespace libtorrent
 				, regular_buffer_size - m_recv_pos);
 			vec[1] = asio::buffer(m_disk_recv_buffer.get()
 				, max_receive - regular_buffer_size + m_recv_pos);
-			m_socket->async_read_some(vec, bind(&peer_connection::on_receive_data
-				, self(), _1, _2));
+			m_socket->async_read_some(
+				vec, make_read_handler(
+					bind(&peer_connection::on_receive_data, self(), _1, _2)));
 		}
 		m_channel_state[download_channel] = peer_info::bw_network;
 	}