/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
/*
 * Implementation of the user-space ashmem API for devices, which have our
 * ashmem-enabled kernel. See ashmem-sim.c for the "fake" tmp-based version,
 * used by the simulator.
 */

#include "IPCListener.h"
#include "Buffering/IPCBuffer.h"
#include "IPCArguments.h"
#include "IPCCommunicator.h"
#include "IPCException.h"
#include "IPCHandler.h"
#include "IPCResult.h"
#include "IPCType.h"
#include <unistd.h>

namespace {
class IPCListenerImpl : public IPCCommunicator,
                        public IPCListener {
public:
    IPCListenerImpl(IPCFutexPageQueue* futexPageQueue, IPCHandler* handler);
    ~IPCListenerImpl() override;
    void listen() override;

private:
    int m_fd;
    IPCHandler* m_handler;
};

IPCListenerImpl::IPCListenerImpl(IPCFutexPageQueue* futexPageQueue, IPCHandler* handler)
    : IPCCommunicator(futexPageQueue)
    , m_handler(handler)
{
}

IPCListenerImpl::~IPCListenerImpl()
{
}

void IPCListenerImpl::listen()
{
    while (true) {
        uint32_t msg = doReadPackage();
        bool isAsync = !!(msg & MSG_FLAG_ASYNC);
        msg &= MSG_MASK;
        if (msg == MSG_END)
            throw IPCException("unexpected MSG_END");
        else if (msg == MSG_TERMINATE) {
            releaseBlob();
            throw IPCException("peer terminates");
        }
        std::unique_ptr<IPCArguments> arguments = assembleArguments();
        releaseBlob();
        IPCArguments*  pArguments = arguments.get();
        std::unique_ptr<IPCResult> sendBack = m_handler->handle(msg, pArguments);
        if (!isAsync) {
            std::unique_ptr<IPCBuffer> resultBuffer = generateResultBuffer(sendBack.get());
            doSendBufferOnly(resultBuffer.get());
        }
    }
}
}

std::unique_ptr<IPCListener> createIPCListener(IPCFutexPageQueue* futexPageQueue, IPCHandler* handler)
{
    return std::unique_ptr<IPCListener>(new IPCListenerImpl(futexPageQueue, handler));
}