/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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package sun.nio.ch;

import java.nio.channels.*;

import java.util.concurrent.*;

import java.nio.ByteBuffer;

import java.nio.BufferOverflowException;

import java.io.IOException;

import java.io.FileDescriptor;

/**

 * Windows implementation of AsynchronousFileChannel using overlapped I/O.

 */

public class WindowsAsynchronousFileChannelImpl

    extends AsynchronousFileChannelImpl

    implements Iocp.OverlappedChannel, Groupable

{

    private static final JavaIOFileDescriptorAccess fdAccess =

        SharedSecrets.getJavaIOFileDescriptorAccess();

    // error when EOF is detected asynchronously.

    private static final int ERROR_HANDLE_EOF = 38;

    // Lazy initialization of default I/O completion port

    private static class DefaultIocpHolder {

        static final Iocp defaultIocp = defaultIocp();

        private static Iocp defaultIocp() {

            try {

                return new Iocp(null, ThreadPool.createDefault()).start();

            } catch (IOException ioe) {

                throw new InternalError(ioe);

            }

        }

    }

    // Used for force/truncate/size methods

    private static final FileDispatcher nd = new FileDispatcherImpl();

    // The handle is extracted for use in native methods invoked from this class.

    private final long handle;

    // The key that identifies the channel's association with the I/O port

    private final int completionKey;

    // I/O completion port (group)

    private final Iocp iocp;

    private final boolean isDefaultIocp;

    // Caches OVERLAPPED structure for each outstanding I/O operation

    private final PendingIoCache ioCache;

    private WindowsAsynchronousFileChannelImpl(FileDescriptor fdObj,

                                               boolean reading,

                                               boolean writing,

                                               Iocp iocp,

                                               boolean isDefaultIocp)

        throws IOException

    {

        super(fdObj, reading, writing, iocp.executor());

        this.handle = fdAccess.getHandle(fdObj);

        this.iocp = iocp;

        this.isDefaultIocp = isDefaultIocp;

        this.ioCache = new PendingIoCache();

        this.completionKey = iocp.associate(this, handle);

    }

    public static AsynchronousFileChannel open(FileDescriptor fdo,

                                               boolean reading,

                                               boolean writing,

                                               ThreadPool pool)

        throws IOException

    {

        Iocp iocp;

        boolean isDefaultIocp;

        if (pool == null) {

            iocp = DefaultIocpHolder.defaultIocp;

            isDefaultIocp = true;

        } else {

            iocp = new Iocp(null, pool).start();

            isDefaultIocp = false;

        }

        try {

            return new

                WindowsAsynchronousFileChannelImpl(fdo, reading, writing, iocp, isDefaultIocp);

        } catch (IOException x) {

            // error binding to port so need to close it (if created for this channel)

            if (!isDefaultIocp)

                iocp.implClose();

            throw x;

        }

    }

    @Override

    public <V,A> PendingFuture<V,A> getByOverlapped(long overlapped) {

        return ioCache.remove(overlapped);

    }

    @Override

    public void close() throws IOException {

        closeLock.writeLock().lock();

        try {

            if (closed)

                return;     // already closed

            closed = true;

        } finally {

            closeLock.writeLock().unlock();

        }

        // invalidate all locks held for this channel

        invalidateAllLocks();

        // close the file

        nd.close(fdObj);

        // waits until all I/O operations have completed

        ioCache.close();

        // disassociate from port

        iocp.disassociate(completionKey);

        // for the non-default group close the port

        if (!isDefaultIocp)

            iocp.detachFromThreadPool();

    }

    @Override

    public AsynchronousChannelGroupImpl group() {

        return iocp;

    }

    /**

     * Translates Throwable to IOException

     */

    private static IOException toIOException(Throwable x) {

        if (x instanceof IOException) {

            if (x instanceof ClosedChannelException)

                x = new AsynchronousCloseException();

            return (IOException)x;

        }

        return new IOException(x);

    }

    @Override

    public long size() throws IOException {

        try {

            begin();

            return nd.size(fdObj);

        } finally {

            end();

        }

    }

    @Override

    public AsynchronousFileChannel truncate(long size) throws IOException {

        if (size < 0)

            throw new IllegalArgumentException("Negative size");

        if (!writing)

            throw new NonWritableChannelException();

        try {

            begin();

            if (size > nd.size(fdObj))

                return this;

            nd.truncate(fdObj, size);

        } finally {

            end();

        }

        return this;

    }

    @Override

    public void force(boolean metaData) throws IOException {

        try {

            begin();

            nd.force(fdObj, metaData);

        } finally {

            end();

        }

    }

    // -- file locking --

    /**

     * Task that initiates locking operation and handles completion result.

     */

    private class LockTask<A> implements Runnable, Iocp.ResultHandler {

        private final long position;

        private final FileLockImpl fli;

        private final PendingFuture<FileLock,A> result;

        LockTask(long position,

                 FileLockImpl fli,

                 PendingFuture<FileLock,A> result)

        {

            this.position = position;

            this.fli = fli;

            this.result = result;

        }

        @Override

        public void run() {

            long overlapped = 0L;

            boolean pending = false;

            try {

                begin();

                // allocate OVERLAPPED structure

                overlapped = ioCache.add(result);

                // synchronize on result to avoid race with handler thread

                // when lock is acquired immediately.

                synchronized (result) {

                    int n = lockFile(handle, position, fli.size(), fli.isShared(),

                                     overlapped);

                    if (n == IOStatus.UNAVAILABLE) {

                        // I/O is pending

                        pending = true;

                        return;

                    }

                    // acquired lock immediately

                    result.setResult(fli);

                }

            } catch (Throwable x) {

                // lock failed or channel closed

                removeFromFileLockTable(fli);

                result.setFailure(toIOException(x));

            } finally {

                if (!pending && overlapped != 0L)

                    ioCache.remove(overlapped);

                end();

            }

            // invoke completion handler

            Invoker.invoke(result);

        }

        @Override

        public void completed(int bytesTransferred, boolean canInvokeDirect) {

            // release waiters and invoke completion handler

            result.setResult(fli);

            if (canInvokeDirect) {

                Invoker.invokeUnchecked(result);

            } else {

                Invoker.invoke(result);

            }

        }

        @Override

        public void failed(int error, IOException x) {

            // lock not acquired so remove from lock table

            removeFromFileLockTable(fli);

            // release waiters

            if (isOpen()) {

                result.setFailure(x);

            } else {

                result.setFailure(new AsynchronousCloseException());

            }

            Invoker.invoke(result);

        }

    }

    @Override

    <A> Future<FileLock> implLock(final long position,

                                  final long size,

                                  final boolean shared,

                                  A attachment,

                                  final CompletionHandler<FileLock,? super A> handler)

    {

        if (shared && !reading)

            throw new NonReadableChannelException();

        if (!shared && !writing)

            throw new NonWritableChannelException();

        // add to lock table

        FileLockImpl fli = addToFileLockTable(position, size, shared);

        if (fli == null) {

            Throwable exc = new ClosedChannelException();

            if (handler == null)

                return CompletedFuture.withFailure(exc);

            Invoker.invoke(this, handler, attachment, null, exc);

            return null;

        }

        // create Future and task that will be invoked to acquire lock

        PendingFuture<FileLock,A> result =

            new PendingFuture<FileLock,A>(this, handler, attachment);

        LockTask<A> lockTask = new LockTask<A>(position, fli, result);

        result.setContext(lockTask);

        // initiate I/O

        lockTask.run();

        return result;

    }

    static final int NO_LOCK = -1;       // Failed to lock

    static final int LOCKED = 0;         // Obtained requested lock

    @Override

    public FileLock tryLock(long position, long size, boolean shared)

        throws IOException

    {

        if (shared && !reading)

            throw new NonReadableChannelException();

        if (!shared && !writing)

            throw new NonWritableChannelException();

        // add to lock table

        final FileLockImpl fli = addToFileLockTable(position, size, shared);

        if (fli == null)

            throw new ClosedChannelException();

        boolean gotLock = false;

        try {

            begin();

            // try to acquire the lock

            int res = nd.lock(fdObj, false, position, size, shared);

            if (res == NO_LOCK)

                return null;

            gotLock = true;

            return fli;

        } finally {

            if (!gotLock)

                removeFromFileLockTable(fli);

            end();

        }

    }

    @Override

    protected void implRelease(FileLockImpl fli) throws IOException {

        nd.release(fdObj, fli.position(), fli.size());

    }

    /**

     * Task that initiates read operation and handles completion result.

     */

    private class ReadTask<A> implements Runnable, Iocp.ResultHandler {

        private final ByteBuffer dst;

        private final int pos, rem;     // buffer position/remaining

        private final long position;    // file position

        private final PendingFuture<Integer,A> result;

        // set to dst if direct; otherwise set to substituted direct buffer

        private volatile ByteBuffer buf;

        ReadTask(ByteBuffer dst,

                 int pos,

                 int rem,

                 long position,

                 PendingFuture<Integer,A> result)

        {

            this.dst = dst;

            this.pos = pos;

            this.rem = rem;

            this.position = position;

            this.result = result;

        }

        void releaseBufferIfSubstituted() {

            if (buf != dst)

                Util.releaseTemporaryDirectBuffer(buf);

        }

        void updatePosition(int bytesTransferred) {

            // if the I/O succeeded then adjust buffer position

            if (bytesTransferred > 0) {

                if (buf == dst) {

                    try {

                        dst.position(pos + bytesTransferred);

                    } catch (IllegalArgumentException x) {

                        // someone has changed the position; ignore

                    }

                } else {

                    // had to substitute direct buffer

                    buf.position(bytesTransferred).flip();

                    try {

                        dst.put(buf);

                    } catch (BufferOverflowException x) {

                        // someone has changed the position; ignore

                    }

                }

            }

        }

        @Override

        public void run() {

            int n = -1;

            long overlapped = 0L;

            long address;

            // Substitute a native buffer if not direct

            if (dst instanceof DirectBuffer) {

                buf = dst;

                address = ((DirectBuffer)dst).address() + pos;

            } else {

                buf = Util.getTemporaryDirectBuffer(rem);

                address = ((DirectBuffer)buf).address();

            }

            boolean pending = false;

            try {

                begin();

                // allocate OVERLAPPED

                overlapped = ioCache.add(result);

                // initiate read

                n = readFile(handle, address, rem, position, overlapped);

                if (n == IOStatus.UNAVAILABLE) {

                    // I/O is pending

                    pending = true;

                    return;

                } else if (n == IOStatus.EOF) {

                    result.setResult(n);

                } else {

                    throw new InternalError("Unexpected result: " + n);

                }

            } catch (Throwable x) {

                // failed to initiate read

                result.setFailure(toIOException(x));

            } finally {

                if (!pending) {

                    // release resources

                    if (overlapped != 0L)

                        ioCache.remove(overlapped);

                    releaseBufferIfSubstituted();

                }

                end();

            }

            // invoke completion handler

            Invoker.invoke(result);

        }

        /**

         * Executed when the I/O has completed

         */

        @Override

        public void completed(int bytesTransferred, boolean canInvokeDirect) {

            updatePosition(bytesTransferred);

            // return direct buffer to cache if substituted

            releaseBufferIfSubstituted();

            // release waiters and invoke completion handler

            result.setResult(bytesTransferred);

            if (canInvokeDirect) {

                Invoker.invokeUnchecked(result);

            } else {

                Invoker.invoke(result);

            }

        }

        @Override

        public void failed(int error, IOException x) {

            // if EOF detected asynchronously then it is reported as error

            if (error == ERROR_HANDLE_EOF) {

                completed(-1, false);

            } else {

                // return direct buffer to cache if substituted

                releaseBufferIfSubstituted();

                // release waiters

                if (isOpen()) {

                    result.setFailure(x);

                } else {

                    result.setFailure(new AsynchronousCloseException());

                }

                Invoker.invoke(result);

            }

        }

    }

    @Override

    <A> Future<Integer> implRead(ByteBuffer dst,

                                 long position,

                                 A attachment,

                                 CompletionHandler<Integer,? super A> handler)

    {

        if (!reading)

            throw new NonReadableChannelException();

        if (position < 0)

            throw new IllegalArgumentException("Negative position");

        if (dst.isReadOnly())

            throw new IllegalArgumentException("Read-only buffer");

        // check if channel is closed

        if (!isOpen()) {

            Throwable exc = new ClosedChannelException();