/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed 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.
 */

package android.net;

import java.io.Closeable;
import java.io.FileDescriptor;
import java.io.IOException;

/**
 * Non-standard class for creating an inbound UNIX-domain socket
 * in the Linux abstract namespace.
 */
public class LocalServerSocket implements Closeable {
    private final LocalSocketImpl impl;
    private final LocalSocketAddress localAddress;

    /** 50 seems a bit much, but it's what was here */
    private static final int LISTEN_BACKLOG = 50;

    /**
     * Creates a new server socket listening at specified name.
     * On the Android platform, the name is created in the Linux
     * abstract namespace (instead of on the filesystem).
     * 
     * @param name address for socket
     * @throws IOException
     */
    public LocalServerSocket(String name) throws IOException
    {
        impl = new LocalSocketImpl();

        impl.create(LocalSocket.SOCKET_STREAM);

        localAddress = new LocalSocketAddress(name);
        impl.bind(localAddress);

        impl.listen(LISTEN_BACKLOG);
    }

    /**
     * Create a LocalServerSocket from a file descriptor that's already
     * been created and bound. listen() will be called immediately on it.
     * Used for cases where file descriptors are passed in via environment
     * variables. The passed-in FileDescriptor is not managed by this class
     * and must be closed by the caller. Calling {@link #close()} on a socket
     * created by this method has no effect.
     *
     * @param fd bound file descriptor
     * @throws IOException
     */
    public LocalServerSocket(FileDescriptor fd) throws IOException
    {
        impl = new LocalSocketImpl(fd);
        impl.listen(LISTEN_BACKLOG);
        localAddress = impl.getSockAddress();
    }

    /**
     * Obtains the socket's local address
     *
     * @return local address
     */
    public LocalSocketAddress getLocalSocketAddress()
    {
        return localAddress;
    }

    /**
     * Accepts a new connection to the socket. Blocks until a new
     * connection arrives.
     *
     * @return a socket representing the new connection.
     * @throws IOException
     */
    public LocalSocket accept() throws IOException
    {
        LocalSocketImpl acceptedImpl = new LocalSocketImpl();

        impl.accept(acceptedImpl);

        return LocalSocket.createLocalSocketForAccept(acceptedImpl);
    }

    /**
     * Returns file descriptor or null if not yet open/already closed
     *
     * @return fd or null
     */
    public FileDescriptor getFileDescriptor() {
        return impl.getFileDescriptor();
    }

    /**
     * Closes server socket.
     * 
     * @throws IOException
     */
    @Override public void close() throws IOException
    {
        impl.close();
    }
}