/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
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* or http://forgerock.org/license/CDDLv1.0.html.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at legal-notices/CDDLv1_0.txt.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2008 Sun Microsystems, Inc.
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*/
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package org.opends.server.protocols.internal;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.concurrent.ArrayBlockingQueue;
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import org.opends.server.protocols.asn1.ASN1;
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import org.opends.server.protocols.asn1.ASN1Writer;
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import org.opends.server.protocols.ldap.LDAPMessage;
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import org.opends.server.types.ByteSequenceReader;
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import org.opends.server.types.ByteStringBuilder;
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/**
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* This class provides an implementation of a
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* {@code java.io.InputStream} that can be used to facilitate internal
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* communication with the Directory Server. On the backend, this
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* input stream will be populated by ASN.1 elements encoded from LDAP
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* messages created from internal operation responses.
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*/
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@org.opends.server.types.PublicAPI(
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stability=org.opends.server.types.StabilityLevel.UNCOMMITTED,
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mayInstantiate=false,
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mayExtend=false,
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mayInvoke=true)
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public final class InternalLDAPInputStream
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extends InputStream
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{
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// The queue of LDAP messages providing the data to be made
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// available to the client.
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private final ArrayBlockingQueue<LDAPMessage> messageQueue;
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// Indicates whether this stream has been closed.
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private boolean closed;
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// The byte buffer with partial data to be written to the client.
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private final ByteStringBuilder messageBuffer;
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// The byte buffer reader.
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private final ByteSequenceReader messageReader;
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// The byte buffer writer.
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private final ASN1Writer writer;
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// The internal LDAP socket serviced by this input stream.
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private final InternalLDAPSocket socket;
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/**
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* Creates a new internal LDAP input stream that will service the
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* provided internal LDAP socket.
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*
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* @param socket The internal LDAP socket serviced by this
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* internal LDAP input stream.
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*/
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public InternalLDAPInputStream(InternalLDAPSocket socket)
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{
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this.socket = socket;
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this.messageQueue = new ArrayBlockingQueue<LDAPMessage>(10);
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this.messageBuffer = new ByteStringBuilder();
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this.messageReader = messageBuffer.asReader();
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this.writer = ASN1.getWriter(messageBuffer);
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this.closed = false;
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}
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/**
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* Adds the provided LDAP message to the set of messages to be
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* returned to the client. Note that this may block if there is
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* already a significant backlog of messages to be returned.
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*
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* @param message The message to add to the set of messages to be
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* returned to the client.
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*/
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@org.opends.server.types.PublicAPI(
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stability=org.opends.server.types.StabilityLevel.PRIVATE,
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mayInstantiate=false,
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mayExtend=false,
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mayInvoke=false)
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void addLDAPMessage(LDAPMessage message)
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{
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// If the stream is closed, then simply drop the message.
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if (closed)
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{
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return;
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}
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try
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{
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messageQueue.put(message);
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return;
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}
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catch (Exception e)
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{
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// This shouldn't happen, but if it does then try three more
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// times before giving up and dropping the message.
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for (int i=0; i < 3; i++)
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{
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try
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{
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messageQueue.put(message);
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break;
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} catch (Exception e2) {}
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}
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return;
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}
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}
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/**
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* Retrieves the number of bytes that can be read (or skipped over)
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* from this input stream without blocking.
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*
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* @return The number of bytes that can be read (or skipped over)
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* from this input stream wihtout blocking.
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* @throws IOException if an I/O error occurs.
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*/
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@Override()
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public synchronized int available() throws IOException
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{
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if (messageReader.remaining() < 1)
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{
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LDAPMessage message = messageQueue.poll();
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if ((message == null) || (message instanceof NullLDAPMessage))
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{
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if (message != null)
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{
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messageQueue.clear();
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closed = true;
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}
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return 0;
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}
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else
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{
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messageBuffer.clear();
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messageReader.rewind();
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message.write(writer);
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}
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}
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return messageReader.remaining();
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}
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/**
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* Closes this input stream. This will add a special marker
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* element to the message queue indicating that the end of the
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* stream has been reached. If the queue is full, thenit will be
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* cleared before adding the marker element.
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*/
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@Override()
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public void close()
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{
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socket.close();
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}
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/**
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* Closes this input stream through an internal mechanism that will
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* not cause an infinite recursion loop by trying to also close the
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* input stream.
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*/
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@org.opends.server.types.PublicAPI(
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stability=org.opends.server.types.StabilityLevel.PRIVATE,
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mayInstantiate=false,
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mayExtend=false,
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mayInvoke=false)
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void closeInternal()
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{
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if (closed)
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{
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return;
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}
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closed = true;
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NullLDAPMessage nullMessage = new NullLDAPMessage();
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while (! messageQueue.offer(nullMessage))
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{
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messageQueue.clear();
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}
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}
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/**
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* Marks the current position in the input stream. This will not
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* have any effect, as this input stream inplementation does not
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* support marking.
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*
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* @param readLimit The maximum limit of bytes that can be read
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* before the mark position becomes invalid.
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*/
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@Override()
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public void mark(int readLimit)
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{
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// No implementation is required.
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}
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/**
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* Indicates whether this input stream inplementation supports the
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* use of the {@code mark} and {@code reset} methods. This
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* implementation does not support that functionality.
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*
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* @return {@code false} because this implementation does not
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* support the use of the {@code mark} and {@code reset}
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* methods.
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*/
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@Override()
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public boolean markSupported()
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{
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return false;
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}
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/**
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* Reads the next byte of data from the input stream, blocking if
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* necessary until there is data available.
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*
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* @return The next byte of data read from the input stream, or -1
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* if the end of the input stream has been reached.
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*
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* @throws IOException If a problem occurs while trying to read
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* data from the stream.
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*/
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@Override()
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public synchronized int read()
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throws IOException
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{
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if (messageReader.remaining() < 1)
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{
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LDAPMessage message;
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try
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{
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message = messageQueue.take();
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}
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catch(InterruptedException ie)
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{
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// Probably because a shutdown was started. EOF
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message = new NullLDAPMessage();
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}
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if ((message == null) || (message instanceof NullLDAPMessage))
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{
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if (message instanceof NullLDAPMessage)
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{
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messageQueue.clear();
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closed = true;
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return -1;
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}
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return 0;
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}
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else
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{
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messageBuffer.clear();
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messageReader.rewind();
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message.write(writer);
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}
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}
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return (0xFF & messageReader.get());
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}
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/**
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* Reads some number of bytes from the input stream, blocking if
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* necessary until there is data available, and adds them to the
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* provided array starting at position 0.
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*
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* @param b The array to which the data is to be written.
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*
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* @return The number of bytes actually written into the
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* provided array, or -1 if the end of the stream has been
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* reached.
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*
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* @throws IOException If a problem occurs while trying to read
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* data from the stream.
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*/
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@Override()
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public int read(byte[] b)
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throws IOException
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{
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return read(b, 0, b.length);
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}
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/**
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* Reads some number of bytes from the input stream, blocking if
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* necessary until there is data available, and adds them to the
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* provided array starting at the specified position.
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*
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* @param b The array to which the data is to be written.
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* @param off The offset in the array at which to start writing
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* data.
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* @param len The maximum number of bytes that may be added to the
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* array.
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*
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* @return The number of bytes actually written into the
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* provided array, or -1 if the end of the stream has been
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* reached.
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*
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* @throws IOException If a problem occurs while trying to read
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* data from the stream.
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*/
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@Override()
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public synchronized int read(byte[] b, int off, int len)
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throws IOException
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{
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if (messageReader.remaining() < 1)
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{
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LDAPMessage message;
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try
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{
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message = messageQueue.take();
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}
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catch(InterruptedException ie)
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{
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// Probably because a shutdown was started. EOF
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message = new NullLDAPMessage();
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}
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if ((message == null) || (message instanceof NullLDAPMessage))
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{
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if (message instanceof NullLDAPMessage)
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{
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messageQueue.clear();
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closed = true;
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return -1;
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}
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return 0;
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}
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else
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{
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messageBuffer.clear();
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messageReader.rewind();
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message.write(writer);
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}
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}
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int actualLen = Math.min(len, messageReader.remaining());
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messageReader.get(b, off, actualLen);
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return actualLen;
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}
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/**
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* Repositions this stream to the position at the time that the
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* {@code mark} method was called on this stream. This will not
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* have any effect, as this input stream inplementation does not
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* support marking.
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*/
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@Override()
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public void reset()
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{
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// No implementation is required.
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}
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/**
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* Skips over and discards up to the specified number of bytes of
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* data from this input stream. This implementation will always
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* skip the requested number of bytes unless the end of the stream
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* is reached.
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*
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* @param n The maximum number of bytes to skip.
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*
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* @return The number of bytes actually skipped.
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*
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* @throws IOException If a problem occurs while trying to read
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* data from the input stream.
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*/
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@Override()
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public synchronized long skip(long n)
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throws IOException
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{
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byte[] b;
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if (n > 8192)
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{
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b = new byte[8192];
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}
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else
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{
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b = new byte[(int) n];
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}
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long totalBytesRead = 0L;
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while (totalBytesRead < n)
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{
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int maxLen = (int) Math.min((n - totalBytesRead), b.length);
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int bytesRead = read(b, 0, maxLen);
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if (bytesRead < 0)
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{
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if (totalBytesRead > 0)
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{
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return totalBytesRead;
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}
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else
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{
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return bytesRead;
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}
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}
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else
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{
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totalBytesRead += bytesRead;
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}
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}
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return totalBytesRead;
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}
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/**
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* Retrieves a string representation of this internal LDAP socket.
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*
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* @return A string representation of this internal LDAP socket.
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*/
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@Override()
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public String toString()
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{
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return "InternalLDAPInputStream";
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}
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}
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