/**
 * @file lleventpoll.h
 * @brief LLEvDescription of the LLEventPoll class.
 *
 * $LicenseInfo:firstyear=2006&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, 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 LL_LLEVENTPOLL_H
#define LL_LLEVENTPOLL_H


class LLHost;

namespace LLEventPolling
{
namespace Details
{
    class LLEventPollImpl;
}
}


class LLEventPoll
    ///< Implements the viewer side of server-to-viewer pushed events.
    ///
    /// This class implements the sole consumer of the EventQueueGet capability
    /// and delivers data, including llsd-encoded llmessage payloads, from
    /// simulator to viewer.
    ///
    /// https://wiki.secondlife.com/wiki/EventQueueGet
    /// The wiki page is neither complete nor entirely correct. Request timeouts
    /// became the de facto method of returning an empty event set to the viewer.
    /// But the timeout behavior was never defined. It was simply whatever
    /// behavior a given grid implementation implemented.
    ///
    /// In SL's case, the path may include reverse proxies, http caches, http and
    /// socks proxies, transparent hijacking, and other horrors. A pitfall for
    /// implementors.
    ///
    /// Current definition of a timeout is any of :
    /// - libcurl easy 28 status code
    /// - Linden 499 special http status code
    /// - RFC - standard 502 - 504 http status codes
    /// If requests are failing too quickly with the above errors, they are treated
    /// as actual errors and not an empty payload. These will count towards a final
    /// error declaration and can lead to disconnection from a simulator or the
    /// entire grid.
{
public:
    LLEventPoll(const std::string& pollURL, const LLHost& sender);
        ///< Start polling the URL.

    virtual ~LLEventPoll();
        ///< will stop polling, canceling any poll in progress.


private:
    std::shared_ptr<LLEventPolling::Details::LLEventPollImpl>  mImpl;
};


#endif // LL_LLEVENTPOLL_H