/**
 * @file _httprequestqueue.cpp
 * @brief
 *
 * $LicenseInfo:firstyear=2012&license=viewerlgpl$
 * 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
 * $/LicenseInfo$
 */

#include "_httprequestqueue.h"

#include "_httpoperation.h"
#include "_mutex.h"


using namespace LLCoreInt;

namespace LLCore
{

HttpRequestQueue * HttpRequestQueue::sInstance(NULL);


HttpRequestQueue::HttpRequestQueue()
    : RefCounted(true),
      mQueueStopped(false)
{
}


HttpRequestQueue::~HttpRequestQueue()
{
    mQueue.clear();
}


void HttpRequestQueue::init()
{
    llassert_always(! sInstance);
    sInstance = new HttpRequestQueue();
}


void HttpRequestQueue::term()
{
    if (sInstance)
    {
        sInstance->release();
        sInstance = NULL;
    }
}


HttpStatus HttpRequestQueue::addOp(const HttpRequestQueue::opPtr_t &op)
{
    bool wake(false);
    {
        HttpScopedLock lock(mQueueMutex);

        if (mQueueStopped)
        {
            // Return op and error to caller
            return HttpStatus(HttpStatus::LLCORE, HE_SHUTTING_DOWN);
        }
        wake = mQueue.empty();
        mQueue.push_back(op);
    }
    if (wake)
    {
        mQueueCV.notify_all();
    }
    return HttpStatus();
}


HttpRequestQueue::opPtr_t HttpRequestQueue::fetchOp(bool wait)
{
    HttpOperation::ptr_t result;

    {
        HttpScopedLock lock(mQueueMutex);

        while (mQueue.empty())
        {
            if (! wait || mQueueStopped)
                return HttpOperation::ptr_t();
            mQueueCV.wait(lock);
        }

        result = mQueue.front();
        mQueue.erase(mQueue.begin());
    }

    // Caller also acquires the reference count
    return result;
}


void HttpRequestQueue::fetchAll(bool wait, OpContainer & ops)
{
    // Not valid putting something back on the queue...
    llassert_always(ops.empty());

    {
        HttpScopedLock lock(mQueueMutex);

        while (mQueue.empty())
        {
            if (! wait || mQueueStopped)
                return;
            mQueueCV.wait(lock);
        }

        mQueue.swap(ops);
    }

    // Caller also acquires the reference counts on each op.
    return;
}


void HttpRequestQueue::wakeAll()
{
    mQueueCV.notify_all();
}


bool HttpRequestQueue::stopQueue()
{
    {
        HttpScopedLock lock(mQueueMutex);

        if (!mQueueStopped)
        {
            mQueueStopped = true;
            wakeAll();
            return true;
        }
        wakeAll();
        return false;
    }
}


} // end namespace LLCore