/**
 * @file _httpreplyqueue.h
 * @brief Internal declarations for the operation reply queue.
 *
 * $LicenseInfo:firstyear=2012&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2012, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef _LLCORE_HTTP_REPLY_QUEUE_H_
#define _LLCORE_HTTP_REPLY_QUEUE_H_


#include "_refcounted.h"
#include "_mutex.h"
#include "boost/noncopyable.hpp"


namespace LLCore
{


class HttpOperation;


/// Almost identical to the HttpRequestQueue class but
/// whereas that class is a singleton and is known to the
/// HttpService object, this queue is 1:1 with HttpRequest
/// instances and isn't explicitly referenced by the
/// service object.  Instead, HttpOperation objects that
/// want to generate replies back to their creators also
/// keep references to the corresponding HttpReplyQueue.
/// The HttpService plumbing then simply delivers replies
/// to the requested reply queue.
///
/// One result of that is that the fetch operations do
/// not have a wait forever option.  The service object
/// doesn't keep handles on everything it would need to
/// notify so it can't wake up sleepers should it need to
/// shutdown.  So only non-blocking or timed-blocking modes
/// are anticipated.  These are how most application consumers
/// will be coded anyway so it shouldn't be too much of a
/// burden.

class HttpReplyQueue : private boost::noncopyable
{

public:
    typedef std::shared_ptr<HttpOperation>    opPtr_t;
    typedef std::shared_ptr<HttpReplyQueue>   ptr_t;

    HttpReplyQueue();
    virtual ~HttpReplyQueue();

public:

    typedef std::vector< opPtr_t > OpContainer;

    /// Insert an object at the back of the reply queue.
    ///
    /// Library also takes possession of one reference count to pass
    /// through the queue.
    ///
    /// Threading:  callable by any thread.
    void addOp(const opPtr_t &op);

    /// Fetch an operation from the head of the queue.  Returns
    /// NULL if none exists.
    ///
    /// Caller acquires reference count on returned operation.
    ///
    /// Threading:  callable by any thread.
    opPtr_t fetchOp();

    /// Caller acquires reference count on each returned operation
    ///
    /// Threading:  callable by any thread.
    void fetchAll(OpContainer & ops);

protected:

    OpContainer                         mQueue;
    LLCoreInt::HttpMutex                mQueueMutex;

}; // end class HttpReplyQueue

}  // end namespace LLCore


#endif  // _LLCORE_HTTP_REPLY_QUEUE_H_