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Diffstat (limited to 'websocketpp/message_buffer/pool.hpp')
| -rw-r--r-- | websocketpp/message_buffer/pool.hpp | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/websocketpp/message_buffer/pool.hpp b/websocketpp/message_buffer/pool.hpp new file mode 100644 index 00000000..3af9e02a --- /dev/null +++ b/websocketpp/message_buffer/pool.hpp @@ -0,0 +1,229 @@ +/* + * Copyright (c) 2014, Peter Thorson. 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 WebSocket++ Project 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 PETER THORSON 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 WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP +#define WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP + +#include <websocketpp/common/memory.hpp> + +#include <string> + +namespace websocketpp { +namespace message_buffer { + +/* # message: + * object that stores a message while it is being sent or received. Contains + * the message payload itself, the message header, the extension data, and the + * opcode. + * + * # connection_message_manager: + * An object that manages all of the message_buffers associated with a given + * connection. Implements the get_message_buffer(size) method that returns + * a message buffer at least size bytes long. + * + * Message buffers are reference counted with shared ownership semantics. Once + * requested from the manager the requester and it's associated downstream code + * may keep a pointer to the message indefinitely at a cost of extra resource + * usage. Once the reference count drops to the point where the manager is the + * only reference the messages is recycled using whatever method is implemented + * in the manager. + * + * # endpoint_message_manager: + * An object that manages connection_message_managers. Implements the + * get_message_manager() method. This is used once by each connection to + * request the message manager that they are supposed to use to manage message + * buffers for their own use. + * + * TYPES OF CONNECTION_MESSAGE_MANAGERS + * - allocate a message with the exact size every time one is requested + * - maintain a pool of pre-allocated messages and return one when needed. + * Recycle previously used messages back into the pool + * + * TYPES OF ENDPOINT_MESSAGE_MANAGERS + * - allocate a new connection manager for each connection. Message pools + * become connection specific. This increases memory usage but improves + * concurrency. + * - allocate a single connection manager and share a pointer to it with all + * connections created by this endpoint. The message pool will be shared + * among all connections, improving memory usage and performance at the cost + * of reduced concurrency + */ + +/// Custom deleter for use in shared_ptrs to message. +/** + * This is used to catch messages about to be deleted and offer the manager the + * ability to recycle them instead. Message::recycle will return true if it was + * successfully recycled and false otherwise. In the case of exceptions or error + * this deleter frees the memory. + */ +template <typename T> +void message_deleter(T* msg) { + try { + if (!msg->recycle()) { + delete msg; + } + } catch (...) { + // TODO: is there a better way to ensure this function doesn't throw? + delete msg; + } +} + +/// Represents a buffer for a single WebSocket message. +/** + * + * + */ +template <typename con_msg_manager> +class message { +public: + typedef lib::shared_ptr<message> ptr; + + typedef typename con_msg_manager::weak_ptr con_msg_man_ptr; + + message(con_msg_man_ptr manager, size_t size = 128) + : m_manager(manager) + , m_payload(size) {} + + frame::opcode::value get_opcode() const { + return m_opcode; + } + const std::string& get_header() const { + return m_header; + } + const std::string& get_extension_data() const { + return m_extension_data; + } + const std::string& get_payload() const { + return m_payload; + } + + /// Recycle the message + /** + * A request to recycle this message was received. Forward that request to + * the connection message manager for processing. Errors and exceptions + * from the manager's recycle member function should be passed back up the + * call chain. The caller to message::recycle will deal with them. + * + * Recycle must *only* be called by the message shared_ptr's destructor. + * Once recycled successfully, ownership of the memory has been passed to + * another system and must not be accessed again. + * + * @return true if the message was successfully recycled, false otherwise. + */ + bool recycle() { + typename con_msg_manager::ptr shared = m_manager.lock(); + + if (shared) { + return shared->(recycle(this)); + } else { + return false; + } + } +private: + con_msg_man_ptr m_manager; + + frame::opcode::value m_opcode; + std::string m_header; + std::string m_extension_data; + std::string m_payload; +}; + +namespace alloc { + +/// A connection message manager that allocates a new message for each +/// request. +template <typename message> +class con_msg_manager { +public: + typedef lib::shared_ptr<con_msg_manager> ptr; + typedef lib::weak_ptr<con_msg_manager> weak_ptr; + + typedef typename message::ptr message_ptr; + + /// Get a message buffer with specified size + /** + * @param size Minimum size in bytes to request for the message payload. + * + * @return A shared pointer to a new message with specified size. + */ + message_ptr get_message(size_t size) const { + return lib::make_shared<message>(size); + } + + /// Recycle a message + /** + * This method shouldn't be called. If it is, return false to indicate an + * error. The rest of the method recycle chain should notice this and free + * the memory. + * + * @param msg The message to be recycled. + * + * @return true if the message was successfully recycled, false otherwse. + */ + bool recycle(message * msg) { + return false; + } +}; + +/// An endpoint message manager that allocates a new manager for each +/// connection. +template <typename con_msg_manager> +class endpoint_msg_manager { +public: + typedef typename con_msg_manager::ptr con_msg_man_ptr; + + /// Get a pointer to a connection message manager + /** + * @return A pointer to the requested connection message manager. + */ + con_msg_man_ptr get_manager() const { + return lib::make_shared<con_msg_manager>(); + } +}; + +} // namespace alloc + +namespace pool { + +/// A connection messages manager that maintains a pool of messages that is +/// used to fulfill get_message requests. +class con_msg_manager { + +}; + +/// An endpoint manager that maintains a shared pool of connection managers +/// and returns an appropriate one for the requesting connection. +class endpoint_msg_manager { + +}; + +} // namespace pool + +} // namespace message_buffer +} // namespace websocketpp + +#endif // WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP |