Squashed 'src/websocketpp/' content from commit 875d420

git-subtree-dir: src/websocketpp
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websocketpp/message_buffer/pool.hpp

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+/*
+ * 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. Impliments 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. Impliments 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