https://github.com/jruby/jruby/jruby-core: JRuby is the effort to recreate the Ruby (https://www.ruby-lang.org) interpreter in Java. (JRuby)
  • headius
  • enebo
  • wmeissner
  • BanzaiMan
  • mkristian 
/*
 ***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * 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.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2008 Charles O Nutter <headius@headius.com>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
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 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/

package org.jruby.util.io;

import java.io.FileDescriptor;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.Channel;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.SeekableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;

import jnr.posix.POSIX;
import jnr.posix.POSIXFactory;

import org.jruby.Ruby;
import org.jruby.util.ByteList;
import org.jruby.util.JRubyFile;
import org.jruby.util.log.Logger;
import org.jruby.util.log.LoggerFactory;

import static com.headius.backport9.buffer.Buffers.flipBuffer;


ChannelDescriptor provides an abstraction similar to the concept of a
"file descriptor" on any POSIX system. In our case, it's a numbered object
(fileno) enclosing a Channel (@see java.nio.channels.Channel), FileDescriptor
(@see java.io.FileDescriptor), and flags under which the original open
occurred
(@see org.jruby.util.io.ModeFlags). Several operations you would normally
expect to use with a POSIX file descriptor are implemented here and used by
higher-level classes to implement higher-level IO behavior.
Note that the channel specified when constructing a ChannelDescriptor will
be reference-counted; that is, until all known references to it through this
class have gone away, it will be left open. This is to support operations
like "dup" which must produce two independent ChannelDescriptor instances
that can be closed separately without affecting the other.
At present there's no way to simulate the behavior on some platforms where
POSIX dup also allows independent positioning information.

/**
 * ChannelDescriptor provides an abstraction similar to the concept of a
 * "file descriptor" on any POSIX system. In our case, it's a numbered object
 * (fileno) enclosing a Channel (@see java.nio.channels.Channel), FileDescriptor
 * (@see java.io.FileDescriptor), and flags under which the original open
 * occurred
 * (@see org.jruby.util.io.ModeFlags). Several operations you would normally
 * expect to use with a POSIX file descriptor are implemented here and used by
 * higher-level classes to implement higher-level IO behavior.
 * 
 * Note that the channel specified when constructing a ChannelDescriptor will
 * be reference-counted; that is, until all known references to it through this
 * class have gone away, it will be left open. This is to support operations
 * like "dup" which must produce two independent ChannelDescriptor instances
 * that can be closed separately without affecting the other.
 * 
 * At present there's no way to simulate the behavior on some platforms where
 * POSIX dup also allows independent positioning information.
 */
@Deprecated
public class ChannelDescriptor {
    private static final Logger LOG = LoggerFactory.getLogger(ChannelDescriptor.class);

    
Whether to log debugging information 
/** Whether to log debugging information */
    private static final boolean DEBUG = false;
    
    
The java.nio.channels.Channel this descriptor wraps. 
/** The java.nio.channels.Channel this descriptor wraps. */
    private Channel channel;
    
The file number (equivalent to the int file descriptor value in POSIX)
for this descriptor. This is generated new for most ChannelDescriptor
instances, except when they need to masquerade as another fileno.

/**
     * The file number (equivalent to the int file descriptor value in POSIX)
     * for this descriptor. This is generated new for most ChannelDescriptor
     * instances, except when they need to masquerade as another fileno.
     */
    private int internalFileno;
    
The java.io.FileDescriptor object for this descriptor. 
/** The java.io.FileDescriptor object for this descriptor. */
    private FileDescriptor fileDescriptor;
    
The original org.jruby.util.io.ModeFlags with which the specified
channel was opened.

/**
     * The original org.jruby.util.io.ModeFlags with which the specified
     * channel was opened.
     */
    private ModeFlags originalModes;
    
The reference count for the provided channel.
Only counts references through ChannelDescriptor instances.

/** 
     * The reference count for the provided channel.
     * Only counts references through ChannelDescriptor instances.
     */
    private AtomicInteger refCounter;

    
Used to work-around blocking problems with STDIN. In most cases null. See ChannelDescriptor(InputStream, ModeFlags, FileDescriptor) for more details. You probably should not use it. 
/**
     * Used to work-around blocking problems with STDIN. In most cases <code>null</code>.
     * See {@link ChannelDescriptor#ChannelDescriptor(java.io.InputStream, ModeFlags, java.io.FileDescriptor)}
     * for more details. You probably should not use it.
     */
    private InputStream baseInputStream;
    
    
Process streams get Channel.newChannel()ed into FileChannel but are not actually
seekable. So instead of just the isSeekable check doing instanceof FileChannel,
we must also add this boolean to check, which we set to false when it's known
that the incoming channel is from a process.
FIXME: This is gross, and it's NIO's fault for not providing a nice way to
tell if a channel is "really" seekable.

/**
     * Process streams get Channel.newChannel()ed into FileChannel but are not actually
     * seekable. So instead of just the isSeekable check doing instanceof FileChannel,
     * we must also add this boolean to check, which we set to false when it's known
     * that the incoming channel is from a process.
     * 
     * FIXME: This is gross, and it's NIO's fault for not providing a nice way to
     * tell if a channel is "really" seekable.
     */
    private boolean canBeSeekable = true;
    
    
If the incoming channel is already in append mode (i.e. it will do the
requisite seeking), we don't want to do our own additional seeks.

/**
     * If the incoming channel is already in append mode (i.e. it will do the
     * requisite seeking), we don't want to do our own additional seeks.
     */
    private boolean isInAppendMode = false;
    
    
Whether the current channe is writable or not.

/**
     * Whether the current channe is writable or not.
     */
    private boolean readableChannel;
    
    
Whether the current channel is readable or not.

/**
     * Whether the current channel is readable or not.
     */
    private boolean writableChannel;
    
    
Whether the current channel is seekable or not.

/**
     * Whether the current channel is seekable or not.
     */
    private boolean seekableChannel;
    
    
Construct a new ChannelDescriptor with the specified channel, file number,
mode flags, file descriptor object and reference counter. This constructor
is only used when constructing a new copy of an existing ChannelDescriptor
with an existing reference count, to allow the two instances to safely
share and appropriately close  a given channel.

Params:
  • channel – The channel for the new descriptor, which will be shared with another
  • fileno – The new file number for the new descriptor
  • originalModes – The mode flags to use as the "origina" set for this descriptor
  • fileDescriptor – The java.io.FileDescriptor object to associate with this ChannelDescriptor
  • refCounter – The reference counter from another ChannelDescriptor being duped.
  • canBeSeekable – If the underlying channel can be considered seekable.
  • isInAppendMode – If the underlying channel is already in append mode.
/**
     * Construct a new ChannelDescriptor with the specified channel, file number,
     * mode flags, file descriptor object and reference counter. This constructor
     * is only used when constructing a new copy of an existing ChannelDescriptor
     * with an existing reference count, to allow the two instances to safely
     * share and appropriately close  a given channel.
     * 
     * @param channel The channel for the new descriptor, which will be shared with another
     * @param fileno The new file number for the new descriptor
     * @param originalModes The mode flags to use as the "origina" set for this descriptor
     * @param fileDescriptor The java.io.FileDescriptor object to associate with this ChannelDescriptor
     * @param refCounter The reference counter from another ChannelDescriptor being duped.
     * @param canBeSeekable If the underlying channel can be considered seekable.
     * @param isInAppendMode If the underlying channel is already in append mode.
     */
    private ChannelDescriptor(Channel channel, int fileno, ModeFlags originalModes, FileDescriptor fileDescriptor, AtomicInteger refCounter, boolean canBeSeekable, boolean isInAppendMode) {
        this.refCounter = refCounter;
        this.channel = channel;
        this.internalFileno = fileno;
        this.originalModes = originalModes;
        this.fileDescriptor = fileDescriptor;
        this.canBeSeekable = canBeSeekable;
        this.isInAppendMode = isInAppendMode;
        
        this.readableChannel = channel instanceof ReadableByteChannel;
        this.writableChannel = channel instanceof WritableByteChannel;
        this.seekableChannel = channel instanceof SeekableByteChannel;

        registerDescriptor(this);
    }

    private ChannelDescriptor(Channel channel, int fileno, ModeFlags originalModes, FileDescriptor fileDescriptor) {
        this(channel, fileno, originalModes, fileDescriptor, new AtomicInteger(1), true, false);
    }

    
Construct a new ChannelDescriptor with the given channel, file number, mode flags,
and file descriptor object. The channel will be kept open until all ChannelDescriptor
references to it have been closed.

Params:
  • channel – The channel for the new descriptor
  • originalModes – The mode flags for the new descriptor
  • fileDescriptor – The java.io.FileDescriptor object for the new descriptor
/**
     * Construct a new ChannelDescriptor with the given channel, file number, mode flags,
     * and file descriptor object. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed.
     * 
     * @param channel The channel for the new descriptor
     * @param originalModes The mode flags for the new descriptor
     * @param fileDescriptor The java.io.FileDescriptor object for the new descriptor
     */
    public ChannelDescriptor(Channel channel, ModeFlags originalModes, FileDescriptor fileDescriptor) {
        this(channel, getNewFileno(), originalModes, fileDescriptor, new AtomicInteger(1), true, false);
    }

    
Construct a new ChannelDescriptor with the given channel, file number, mode flags,
and file descriptor object. The channel will be kept open until all ChannelDescriptor
references to it have been closed.

Params:
  • channel – The channel for the new descriptor
  • originalModes – The mode flags for the new descriptor
  • fileDescriptor – The java.io.FileDescriptor object for the new descriptor
/**
     * Construct a new ChannelDescriptor with the given channel, file number, mode flags,
     * and file descriptor object. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed.
     * 
     * @param channel The channel for the new descriptor
     * @param originalModes The mode flags for the new descriptor
     * @param fileDescriptor The java.io.FileDescriptor object for the new descriptor
     */
    public ChannelDescriptor(Channel channel, ModeFlags originalModes, FileDescriptor fileDescriptor, boolean isInAppendMode) {
        this(channel, getNewFileno(), originalModes, fileDescriptor, new AtomicInteger(1), true, isInAppendMode);
    }

    
Construct a new ChannelDescriptor with the given channel, file number, mode flags,
and file descriptor object. The channel will be kept open until all ChannelDescriptor
references to it have been closed.

Params:
  • channel – The channel for the new descriptor
  • originalModes – The mode flags for the new descriptor
/**
     * Construct a new ChannelDescriptor with the given channel, file number, mode flags,
     * and file descriptor object. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed.
     *
     * @param channel The channel for the new descriptor
     * @param originalModes The mode flags for the new descriptor
     */
    public ChannelDescriptor(Channel channel, ModeFlags originalModes) {
        this(channel, getNewFileno(), originalModes, FilenoUtil.getDescriptorFromChannel(channel), new AtomicInteger(1), true, false);
    }

    
Special constructor to create the ChannelDescriptor out of the stream, file number,
mode flags, and file descriptor object. The channel will be created from the
provided stream. The channel will be kept open until all ChannelDescriptor
references to it have been closed. Note: in most cases, you should not
use this constructor, it's reserved mostly for STDIN.

Params:
  • baseInputStream – The stream to create the channel for the new descriptor
  • originalModes – The mode flags for the new descriptor
  • fileDescriptor – The java.io.FileDescriptor object for the new descriptor
/**
     * Special constructor to create the ChannelDescriptor out of the stream, file number,
     * mode flags, and file descriptor object. The channel will be created from the
     * provided stream. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed. <b>Note:</b> in most cases, you should not
     * use this constructor, it's reserved mostly for STDIN.
     *
     * @param baseInputStream The stream to create the channel for the new descriptor
     * @param originalModes The mode flags for the new descriptor
     * @param fileDescriptor The java.io.FileDescriptor object for the new descriptor
     */
    public ChannelDescriptor(InputStream baseInputStream, ModeFlags originalModes, FileDescriptor fileDescriptor) {
        // The reason why we need the stream is to be able to invoke available() on it.
        // STDIN in Java is non-interruptible, non-selectable, and attempt to read
        // on such stream might lead to thread being blocked without *any* way to unblock it.
        // That's where available() comes it, so at least we could check whether
        // anything is available to be read without blocking.
        this(Channels.newChannel(baseInputStream), getNewFileno(), originalModes, fileDescriptor, new AtomicInteger(1), true, false);
        this.baseInputStream = baseInputStream;
    }

    
Special constructor to create the ChannelDescriptor out of the stream, file number,
mode flags, and file descriptor object. The channel will be created from the
provided stream. The channel will be kept open until all ChannelDescriptor
references to it have been closed. Note: in most cases, you should not
use this constructor, it's reserved mostly for STDIN.

Params:
  • baseInputStream – The stream to create the channel for the new descriptor
  • originalModes – The mode flags for the new descriptor
/**
     * Special constructor to create the ChannelDescriptor out of the stream, file number,
     * mode flags, and file descriptor object. The channel will be created from the
     * provided stream. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed. <b>Note:</b> in most cases, you should not
     * use this constructor, it's reserved mostly for STDIN.
     *
     * @param baseInputStream The stream to create the channel for the new descriptor
     * @param originalModes The mode flags for the new descriptor
     */
    public ChannelDescriptor(InputStream baseInputStream, ModeFlags originalModes) {
        // The reason why we need the stream is to be able to invoke available() on it.
        // STDIN in Java is non-interruptible, non-selectable, and attempt to read
        // on such stream might lead to thread being blocked without *any* way to unblock it.
        // That's where available() comes it, so at least we could check whether
        // anything is available to be read without blocking.
        this(Channels.newChannel(baseInputStream), getNewFileno(), originalModes, new FileDescriptor(), new AtomicInteger(1), true, false);
        this.baseInputStream = baseInputStream;
    }

    
Construct a new ChannelDescriptor with the given channel, file number,
and file descriptor object. The channel will be kept open until all ChannelDescriptor
references to it have been closed. The channel's capabilities will be used
to determine the "original" set of mode flags.

Params:
  • channel – The channel for the new descriptor
  • fileDescriptor – The java.io.FileDescriptor object for the new descriptor
/**
     * Construct a new ChannelDescriptor with the given channel, file number,
     * and file descriptor object. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed. The channel's capabilities will be used
     * to determine the "original" set of mode flags.
     * 
     * @param channel The channel for the new descriptor
     * @param fileDescriptor The java.io.FileDescriptor object for the new descriptor
     */
    public ChannelDescriptor(Channel channel, FileDescriptor fileDescriptor) throws InvalidValueException {
        this(channel, ModeFlags.getModesFromChannel(channel), fileDescriptor);
    }
    
    @Deprecated
    public ChannelDescriptor(Channel channel, int fileno, FileDescriptor fileDescriptor) throws InvalidValueException {
        this(channel, ModeFlags.getModesFromChannel(channel), fileDescriptor);
    }

    
Construct a new ChannelDescriptor with the given channel, file number,
and file descriptor object. The channel will be kept open until all ChannelDescriptor
references to it have been closed. The channel's capabilities will be used
to determine the "original" set of mode flags. This version generates a
new fileno.

Params:
  • channel – The channel for the new descriptor
/**
     * Construct a new ChannelDescriptor with the given channel, file number,
     * and file descriptor object. The channel will be kept open until all ChannelDescriptor
     * references to it have been closed. The channel's capabilities will be used
     * to determine the "original" set of mode flags. This version generates a
     * new fileno.
     *
     * @param channel The channel for the new descriptor
     */
    public ChannelDescriptor(Channel channel) throws InvalidValueException {
        this(channel, ModeFlags.getModesFromChannel(channel), FilenoUtil.getDescriptorFromChannel(channel));
    }

    
Get this descriptor's file number.

Returns:the fileno for this descriptor
/**
     * Get this descriptor's file number.
     * 
     * @return the fileno for this descriptor
     */
    public int getFileno() {
        return internalFileno;
    }
    
    
Get the FileDescriptor object associated with this descriptor. This is
not guaranteed to be a "valid" descriptor in the terms of the Java
implementation, but is provided for completeness and for cases where it
is possible to get a valid FileDescriptor for a given channel.

Returns:the java.io.FileDescriptor object associated with this descriptor
/**
     * Get the FileDescriptor object associated with this descriptor. This is
     * not guaranteed to be a "valid" descriptor in the terms of the Java
     * implementation, but is provided for completeness and for cases where it
     * is possible to get a valid FileDescriptor for a given channel.
     * 
     * @return the java.io.FileDescriptor object associated with this descriptor
     */
    public FileDescriptor getFileDescriptor() {
        return fileDescriptor;
    }

    
The channel associated with this descriptor. The channel will be reference
counted through ChannelDescriptor and kept open until all ChannelDescriptor
objects have been closed. References that leave ChannelDescriptor through
this method will not be counted.

Returns:the java.nio.channels.Channel associated with this descriptor
/**
     * The channel associated with this descriptor. The channel will be reference
     * counted through ChannelDescriptor and kept open until all ChannelDescriptor
     * objects have been closed. References that leave ChannelDescriptor through
     * this method will not be counted.
     * 
     * @return the java.nio.channels.Channel associated with this descriptor
     */
    public Channel getChannel() {
        return channel;
    }

    
This is intentionally non-public, since it should not be really used outside of very limited use case (handling of STDIN). See ChannelDescriptor(InputStream, ModeFlags, FileDescriptor) for more info. 
/**
     * This is intentionally non-public, since it should not be really
     * used outside of very limited use case (handling of STDIN).
     * See {@link ChannelDescriptor#ChannelDescriptor(java.io.InputStream, ModeFlags, java.io.FileDescriptor)}
     * for more info.
     */
    /*package-protected*/ InputStream getBaseInputStream() {
        return baseInputStream;
    }

    
Whether the channel associated with this descriptor is seekable (i.e.
whether it is instanceof SeekableByteChannel).

Returns:true if the associated channel is seekable, false otherwise
/**
     * Whether the channel associated with this descriptor is seekable (i.e.
     * whether it is instanceof SeekableByteChannel).
     * 
     * @return true if the associated channel is seekable, false otherwise
     */
    public boolean isSeekable() {
        return canBeSeekable && seekableChannel;
    }
    
    
Set the channel to be explicitly seekable or not, for streams that appear
to be seekable with the instanceof SeekableByteChannel check.

Params:
  • canBeSeekable – Whether the channel is seekable or not.
/**
     * Set the channel to be explicitly seekable or not, for streams that appear
     * to be seekable with the instanceof SeekableByteChannel check.
     * 
     * @param canBeSeekable Whether the channel is seekable or not.
     */
    public void setCanBeSeekable(boolean canBeSeekable) {
        this.canBeSeekable = canBeSeekable;
    }
    
    
Whether the channel associated with this descriptor is a NullChannel,
for which many operations are simply noops.

/**
     * Whether the channel associated with this descriptor is a NullChannel,
     * for which many operations are simply noops.
     */
    public boolean isNull() {
        return channel instanceof NullChannel;
    }

    
Whether the channel associated with this descriptor is writable (i.e.
whether it is instanceof WritableByteChannel).

Returns:true if the associated channel is writable, false otherwise
/**
     * Whether the channel associated with this descriptor is writable (i.e.
     * whether it is instanceof WritableByteChannel).
     * 
     * @return true if the associated channel is writable, false otherwise
     */
    public boolean isWritable() {
        return writableChannel;
    }

    
Whether the channel associated with this descriptor is readable (i.e.
whether it is instanceof ReadableByteChannel).

Returns:true if the associated channel is readable, false otherwise
/**
     * Whether the channel associated with this descriptor is readable (i.e.
     * whether it is instanceof ReadableByteChannel).
     * 
     * @return true if the associated channel is readable, false otherwise
     */
    public boolean isReadable() {
        return readableChannel;
    }
    
    
Whether the channel associated with this descriptor is open.

Returns:true if the associated channel is open, false otherwise
/**
     * Whether the channel associated with this descriptor is open.
     * 
     * @return true if the associated channel is open, false otherwise
     */
    public boolean isOpen() {
        return channel.isOpen();
    }
    
    
Check whether the isOpen returns true, raising a BadDescriptorException if
it returns false.

Throws:
  • BadDescriptorException – if isOpen returns false
/**
     * Check whether the isOpen returns true, raising a BadDescriptorException if
     * it returns false.
     * 
     * @throws org.jruby.util.io.BadDescriptorException if isOpen returns false
     */
    public void checkOpen() throws BadDescriptorException {
        if (!isOpen()) {
            throw new BadDescriptorException();
        }
    }
    
    
Get the original mode flags for the descriptor.

Returns:the original mode flags for the descriptor
/**
     * Get the original mode flags for the descriptor.
     * 
     * @return the original mode flags for the descriptor
     */
    public ModeFlags getOriginalModes() {
        return originalModes;
    }
    
    
Check whether a specified set of mode flags is a superset of this
descriptor's original set of mode flags.

Params:
  • newModes – The modes to confirm as superset
Throws:
/**
     * Check whether a specified set of mode flags is a superset of this
     * descriptor's original set of mode flags.
     * 
     * @param newModes The modes to confirm as superset
     * @throws org.jruby.util.io.InvalidValueException if the modes are not a superset
     */
    public void checkNewModes(ModeFlags newModes) throws InvalidValueException {
        if (!newModes.isSubsetOf(originalModes)) {
            throw new InvalidValueException();
        }
    }
    
    
Mimics the POSIX dup(2) function, returning a new descriptor that references
the same open channel.

Returns:A duplicate ChannelDescriptor based on this one
/**
     * Mimics the POSIX dup(2) function, returning a new descriptor that references
     * the same open channel.
     * 
     * @return A duplicate ChannelDescriptor based on this one
     */
    public ChannelDescriptor dup() {
        synchronized (refCounter) {
            refCounter.incrementAndGet();

            int newFileno = getNewFileno();
            
            if (DEBUG) LOG.info("Reopen fileno {}, refs now: {}", newFileno, refCounter.get());

            return new ChannelDescriptor(channel, newFileno, originalModes, fileDescriptor, refCounter, canBeSeekable, isInAppendMode);
        }
    }
    
    
Mimics the POSIX dup2(2) function, returning a new descriptor that references
the same open channel but with a specified fileno.

Params:
  • fileno – The fileno to use for the new descriptor
Returns:A duplicate ChannelDescriptor based on this one
/**
     * Mimics the POSIX dup2(2) function, returning a new descriptor that references
     * the same open channel but with a specified fileno.
     * 
     * @param fileno The fileno to use for the new descriptor
     * @return A duplicate ChannelDescriptor based on this one
     */
    public ChannelDescriptor dup2(int fileno) {
        synchronized (refCounter) {
            refCounter.incrementAndGet();

            if (DEBUG) LOG.info("Reopen fileno {}, refs now: {}", fileno, refCounter.get());

            return new ChannelDescriptor(channel, fileno, originalModes, fileDescriptor, refCounter, canBeSeekable, isInAppendMode);
        }
    }
    
    
Mimics the POSIX dup2(2) function, returning a new descriptor that references
the same open channel but with a specified fileno. This differs from the fileno
version by making the target descriptor into a new reference to the current
descriptor's channel, closing what it originally pointed to and preserving
its original fileno.

Params:
  • other – the descriptor to dup this one into
/**
     * Mimics the POSIX dup2(2) function, returning a new descriptor that references
     * the same open channel but with a specified fileno. This differs from the fileno
     * version by making the target descriptor into a new reference to the current
     * descriptor's channel, closing what it originally pointed to and preserving
     * its original fileno.
     *
     * @param other the descriptor to dup this one into
     */
    public void dup2Into(ChannelDescriptor other) throws BadDescriptorException, IOException {
        synchronized (refCounter) {
            refCounter.incrementAndGet();

            if (DEBUG) LOG.info("Reopen fileno {}, refs now: {}", internalFileno, refCounter.get());

            other.close();
            
            other.channel = channel;
            other.originalModes = originalModes;
            other.fileDescriptor = fileDescriptor;
            other.refCounter = refCounter;
            other.canBeSeekable = canBeSeekable;
            other.readableChannel = readableChannel;
            other.writableChannel = writableChannel;
            other.seekableChannel = seekableChannel;
        }
    }

    public ChannelDescriptor reopen(Channel channel, ModeFlags modes) {
        return new ChannelDescriptor(channel, internalFileno, modes, fileDescriptor);
    }

    public ChannelDescriptor reopen(RandomAccessFile file, ModeFlags modes) throws IOException {
        return new ChannelDescriptor(file.getChannel(), internalFileno, modes, file.getFD());
    }
    
    
Perform a low-level seek operation on the associated channel if it is
instanceof SeekableByteChannel, or raise PipeException if it is not a SeekableByteChannel.
Calls checkOpen to confirm the target channel is open. This is equivalent
to the lseek(2) POSIX function, and like that function it bypasses any
buffer flushing or invalidation as in ChannelStream.fseek.

Params:
  • offset – the offset value to use
  • whence – whence to seek
Throws:
Returns:the new offset into the SeekableByteChannel.
/**
     * Perform a low-level seek operation on the associated channel if it is
     * instanceof SeekableByteChannel, or raise PipeException if it is not a SeekableByteChannel.
     * Calls checkOpen to confirm the target channel is open. This is equivalent
     * to the lseek(2) POSIX function, and like that function it bypasses any
     * buffer flushing or invalidation as in ChannelStream.fseek.
     * 
     * @param offset the offset value to use
     * @param whence whence to seek
     * @throws java.io.IOException If there is an exception while seeking
     * @throws org.jruby.util.io.InvalidValueException If the value specified for
     * offset or whence is invalid
     * @throws org.jruby.util.io.PipeException If the target channel is not seekable
     * @throws org.jruby.util.io.BadDescriptorException If the target channel is
     * already closed.
     * @return the new offset into the SeekableByteChannel.
     */
    public long lseek(long offset, int whence) throws IOException, InvalidValueException, PipeException, BadDescriptorException {
        if (seekableChannel) {
            checkOpen();
            
            SeekableByteChannel channel = (SeekableByteChannel) this.channel;
            try {
                long pos;
                switch (whence) {
                case PosixShim.SEEK_SET:
                    pos = offset;
                    channel.position(pos);
                    break;
                case PosixShim.SEEK_CUR:
                    pos = channel.position() + offset;
                    channel.position(pos);
                    break;
                case PosixShim.SEEK_END:
                    pos = channel.size() + offset;
                    channel.position(pos);
                    break;
                default:
                    throw new InvalidValueException();
                }
                return pos;
            } catch (IllegalArgumentException e) {
                throw new InvalidValueException();
            } catch (IOException ioe) {
                // "invalid seek" means it's an ESPIPE, so we rethrow as a PipeException()
                if (ioe.getMessage().equals("Illegal seek")) {
                    throw new PipeException();
                }
                throw ioe;
            }
        } else {
            throw new PipeException();
        }
    }

    
Perform a low-level read of the specified number of bytes into the specified
byte list. The incoming bytes will be appended to the byte list. This is
equivalent to the read(2) POSIX function, and like that function it
ignores read and write buffers defined elsewhere.

Params:
  • number – the number of bytes to read
  • byteList – the byte list on which to append the incoming bytes
Throws:
See Also:
Returns:the number of bytes actually read
/**
     * Perform a low-level read of the specified number of bytes into the specified
     * byte list. The incoming bytes will be appended to the byte list. This is
     * equivalent to the read(2) POSIX function, and like that function it
     * ignores read and write buffers defined elsewhere.
     * 
     * @param number the number of bytes to read
     * @param byteList the byte list on which to append the incoming bytes
     * @return the number of bytes actually read
     * @throws java.io.IOException if there is an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed.
     * @see org.jruby.util.ByteList
     */
    public int read(int number, ByteList byteList) throws IOException, BadDescriptorException {
        checkOpen();
        
        byteList.ensure(byteList.length() + number);
        int bytesRead = read(ByteBuffer.wrap(byteList.getUnsafeBytes(),
                byteList.begin() + byteList.length(), number));
        if (bytesRead > 0) {
            byteList.length(byteList.length() + bytesRead);
        }
        return bytesRead;
    }
    
    
Perform a low-level read of the remaining number of bytes into the specified
byte buffer. The incoming bytes will be used to fill the remaining space in
the target byte buffer. This is equivalent to the read(2) POSIX function,
and like that function it ignores read and write buffers defined elsewhere.

Params:
  • buffer – the java.nio.ByteBuffer in which to put the incoming bytes
Throws:
See Also:
Returns:the number of bytes actually read
/**
     * Perform a low-level read of the remaining number of bytes into the specified
     * byte buffer. The incoming bytes will be used to fill the remaining space in
     * the target byte buffer. This is equivalent to the read(2) POSIX function,
     * and like that function it ignores read and write buffers defined elsewhere.
     * 
     * @param buffer the java.nio.ByteBuffer in which to put the incoming bytes
     * @return the number of bytes actually read
     * @throws java.io.IOException if there is an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     * @see java.nio.ByteBuffer
     */
    public int read(ByteBuffer buffer) throws IOException, BadDescriptorException {
        checkOpen();

        // TODO: It would be nice to throw a better error for this
        if (!isReadable()) {
            throw new BadDescriptorException();
        }
        ReadableByteChannel readChannel = (ReadableByteChannel) channel;
        int bytesRead = 0;
        bytesRead = readChannel.read(buffer);

        return bytesRead;
    }
    
    
Write the bytes in the specified byte list to the associated channel.

Params:
  • buffer – the byte list containing the bytes to be written
Throws:
Returns:the number of bytes actually written
/**
     * Write the bytes in the specified byte list to the associated channel.
     * 
     * @param buffer the byte list containing the bytes to be written
     * @return the number of bytes actually written
     * @throws java.io.IOException if there is an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     */
    public int internalWrite(ByteBuffer buffer) throws IOException, BadDescriptorException {
        checkOpen();

        // TODO: It would be nice to throw a better error for this
        if (!isWritable()) {
            throw new BadDescriptorException();
        }
        
        WritableByteChannel writeChannel = (WritableByteChannel)channel;
        
        // if appendable, we always seek to the end before writing
        if (isSeekable() && originalModes.isAppendable()) {
            // if already in append mode, we don't do our own seeking
            if (!isInAppendMode) {
                SeekableByteChannel fileChannel = (SeekableByteChannel) channel;
                fileChannel.position(fileChannel.size());
            }
        }
        
        return writeChannel.write(buffer);
    }
    
    
Write the bytes in the specified byte list to the associated channel.

Params:
  • buffer – the byte list containing the bytes to be written
Throws:
Returns:the number of bytes actually written
/**
     * Write the bytes in the specified byte list to the associated channel.
     * 
     * @param buffer the byte list containing the bytes to be written
     * @return the number of bytes actually written
     * @throws java.io.IOException if there is an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     */
    public int write(ByteBuffer buffer) throws IOException, BadDescriptorException {
        checkOpen();
        
        return internalWrite(buffer);
    }
    
    
Write the bytes in the specified byte list to the associated channel.

Params:
  • buf – the byte list containing the bytes to be written
Throws:
Returns:the number of bytes actually written
/**
     * Write the bytes in the specified byte list to the associated channel.
     * 
     * @param buf the byte list containing the bytes to be written
     * @return the number of bytes actually written
     * @throws java.io.IOException if there is an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     */
    public int write(ByteList buf) throws IOException, BadDescriptorException {
        checkOpen();
        
        return internalWrite(ByteBuffer.wrap(buf.getUnsafeBytes(), buf.begin(), buf.length()));
    }

    
Write the bytes in the specified byte list to the associated channel.

Params:
  • buf – the byte list containing the bytes to be written
  • offset – the offset to start at. this is relative to the begin variable in the but
  • len – the amount of bytes to write. this should not be longer than the buffer
Throws:
Returns:the number of bytes actually written
/**
     * Write the bytes in the specified byte list to the associated channel.
     * 
     * @param buf the byte list containing the bytes to be written
     * @param offset the offset to start at. this is relative to the begin variable in the but
     * @param len the amount of bytes to write. this should not be longer than the buffer
     * @return the number of bytes actually written
     * @throws java.io.IOException if there is an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     */
    public int write(ByteList buf, int offset, int len) throws IOException, BadDescriptorException {
        checkOpen();
        
        return internalWrite(ByteBuffer.wrap(buf.getUnsafeBytes(), buf.begin()+offset, len));
    }
    
    
Write the byte represented by the specified int to the associated channel.

Params:
  • c – The byte to write
Throws:
Returns:1 if the byte was written, 0 if not and -1 if there was an error
(@see java.nio.channels.WritableByteChannel.write(java.nio.ByteBuffer))
/**
     * Write the byte represented by the specified int to the associated channel.
     * 
     * @param c The byte to write
     * @return 1 if the byte was written, 0 if not and -1 if there was an error
     * (@see java.nio.channels.WritableByteChannel.write(java.nio.ByteBuffer))
     * @throws java.io.IOException If there was an exception during IO
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     */
    public int write(int c) throws IOException, BadDescriptorException {
        checkOpen();
        
        ByteBuffer buf = ByteBuffer.allocate(1);
        buf.put((byte)c);
        flipBuffer(buf);

        return internalWrite(buf);
    }

    
Open a new descriptor using the given working directory, file path,
mode flags, and file permission. This is equivalent to the open(2)
POSIX function. See org.jruby.util.io.ChannelDescriptor.open(String, String, ModeFlags, int, POSIX)
for the version that also sets file permissions.

Params:
  • cwd – the "current working directory" to use when opening the file
  • path – the file path to open
  • flags – the mode flags to use for opening the file
Returns:a new ChannelDescriptor based on the specified parameters
/**
     * Open a new descriptor using the given working directory, file path,
     * mode flags, and file permission. This is equivalent to the open(2)
     * POSIX function. See org.jruby.util.io.ChannelDescriptor.open(String, String, ModeFlags, int, POSIX)
     * for the version that also sets file permissions.
     *
     * @param cwd the "current working directory" to use when opening the file
     * @param path the file path to open
     * @param flags the mode flags to use for opening the file
     * @return a new ChannelDescriptor based on the specified parameters
     */
    @Deprecated
    public static ChannelDescriptor open(String cwd, String path, ModeFlags flags) throws FileNotFoundException, DirectoryAsFileException, FileExistsException, IOException {
        return open(cwd, path, flags, 0, POSIXFactory.getPOSIX(), null);
    }

    
Open a new descriptor using the given working directory, file path,
mode flags, and file permission. This is equivalent to the open(2)
POSIX function. See org.jruby.util.io.ChannelDescriptor.open(String, String, ModeFlags, int, POSIX)
for the version that also sets file permissions.

Params:
  • cwd – the "current working directory" to use when opening the file
  • path – the file path to open
  • flags – the mode flags to use for opening the file
  • classLoader – a ClassLoader to use for classpath: resources
Returns:a new ChannelDescriptor based on the specified parameters
/**
     * Open a new descriptor using the given working directory, file path,
     * mode flags, and file permission. This is equivalent to the open(2)
     * POSIX function. See org.jruby.util.io.ChannelDescriptor.open(String, String, ModeFlags, int, POSIX)
     * for the version that also sets file permissions.
     *
     * @param cwd the "current working directory" to use when opening the file
     * @param path the file path to open
     * @param flags the mode flags to use for opening the file
     * @param classLoader a ClassLoader to use for classpath: resources
     * @return a new ChannelDescriptor based on the specified parameters
     */
    @Deprecated
    public static ChannelDescriptor open(String cwd, String path, ModeFlags flags, ClassLoader classLoader) throws FileNotFoundException, DirectoryAsFileException, FileExistsException, IOException {
        return open(cwd, path, flags, 0, POSIXFactory.getPOSIX(), classLoader);
    }

    
Open a new descriptor using the given working directory, file path,
mode flags, and file permission. This is equivalent to the open(2)
POSIX function.

Params:
  • cwd – the "current working directory" to use when opening the file
  • path – the file path to open
  • flags – the mode flags to use for opening the file
  • perm – the file permissions to use when creating a new file (currently
unobserved)
  • posix – a POSIX api implementation, used for setting permissions; if null, permissions are ignored
Returns:a new ChannelDescriptor based on the specified parameters
/**
     * Open a new descriptor using the given working directory, file path,
     * mode flags, and file permission. This is equivalent to the open(2)
     * POSIX function.
     *
     * @param cwd the "current working directory" to use when opening the file
     * @param path the file path to open
     * @param flags the mode flags to use for opening the file
     * @param perm the file permissions to use when creating a new file (currently
     * unobserved)
     * @param posix a POSIX api implementation, used for setting permissions; if null, permissions are ignored
     * @return a new ChannelDescriptor based on the specified parameters
     */
    @Deprecated
    public static ChannelDescriptor open(String cwd, String path, ModeFlags flags, int perm, POSIX posix) throws FileNotFoundException, DirectoryAsFileException, FileExistsException, IOException {
        return open(cwd, path, flags, perm, posix, null);
    }

    
Open a new descriptor using the given working directory, file path,
mode flags, and file permission. This is equivalent to the open(2)
POSIX function.

Params:
  • cwd – the "current working directory" to use when opening the file
  • path – the file path to open
  • flags – the mode flags to use for opening the file
  • perm – the file permissions to use when creating a new file (currently
unobserved)
  • posix – a POSIX api implementation, used for setting permissions; if null, permissions are ignored
  • classLoader – a ClassLoader to use for classpath: resources
Returns:a new ChannelDescriptor based on the specified parameters
/**
     * Open a new descriptor using the given working directory, file path,
     * mode flags, and file permission. This is equivalent to the open(2)
     * POSIX function.
     *
     * @param cwd the "current working directory" to use when opening the file
     * @param path the file path to open
     * @param flags the mode flags to use for opening the file
     * @param perm the file permissions to use when creating a new file (currently
     * unobserved)
     * @param posix a POSIX api implementation, used for setting permissions; if null, permissions are ignored
     * @param classLoader a ClassLoader to use for classpath: resources
     * @return a new ChannelDescriptor based on the specified parameters
     */
    @Deprecated
    public static ChannelDescriptor open(String cwd, String path, ModeFlags flags, int perm, POSIX posix, ClassLoader classLoader) throws FileNotFoundException, DirectoryAsFileException, FileExistsException, IOException {
        try {
            if (path.equals("/dev/null") || path.equalsIgnoreCase("nul:") || path.equalsIgnoreCase("nul")) {
                Channel nullChannel = new NullChannel();
                // FIXME: don't use RubyIO for this
                return new ChannelDescriptor(nullChannel, flags);
            }

            if (path.startsWith("classpath:/") && classLoader != null) {
                path = path.substring("classpath:/".length());
                InputStream is = classLoader.getResourceAsStream(path);
                // FIXME: don't use RubyIO for this
                return new ChannelDescriptor(Channels.newChannel(is), flags);
            }

            Channel ch = JRubyFile.createResource(Ruby.getGlobalRuntime(), cwd, path).openChannel(flags, perm);
            return new ChannelDescriptor(ch, flags);
        } catch (NullPointerException npe) { npe.printStackTrace(); throw npe; }
    }

    
Close this descriptor. If in closing the last ChannelDescriptor reference
to the associate channel is closed, the channel itself will be closed.

Throws:
  • BadDescriptorException – if the associated
channel is already closed
  • IOException – if there is an exception during IO
/**
     * Close this descriptor. If in closing the last ChannelDescriptor reference
     * to the associate channel is closed, the channel itself will be closed.
     *
     * @throws org.jruby.util.io.BadDescriptorException if the associated
     * channel is already closed
     * @throws java.io.IOException if there is an exception during IO
     */
    public void close() throws BadDescriptorException, IOException {
        // tidy up
        finish(true);

    }

    void finish(boolean close) throws BadDescriptorException, IOException {
        synchronized (refCounter) {
            // if refcount is at or below zero, we're no longer valid
            if (refCounter.get() <= 0) {
                throw new BadDescriptorException();
            }

            // if channel is already closed, we're no longer valid
            if (!channel.isOpen()) {
                throw new BadDescriptorException();
            }

            // otherwise decrement and possibly close as normal
            if (close) {
                int count = refCounter.decrementAndGet();

                if (DEBUG) LOG.info("Descriptor for fileno {} refs: {}", internalFileno, count);

                if (count <= 0) {
                    // if we're the last referrer, close the channel
                    try {
                        channel.close();
                    } finally {
                        unregisterDescriptor(internalFileno);
                    }
                }
            }
        }
    }

    // Choose something sufficiently high so new IO stuff does not trample as soon
    @Deprecated
    private static final AtomicInteger NEXT_FILENO = new AtomicInteger(Integer.MAX_VALUE / 2);

    @Deprecated
    private static final Map<Integer, ChannelDescriptor> FILENO_MAP = Collections.synchronizedMap(new HashMap<Integer, ChannelDescriptor>());

    @Deprecated
    public static int getNewFileno() {
        return NEXT_FILENO.getAndIncrement();
    }

    @Deprecated
    private static void registerDescriptor(ChannelDescriptor descriptor) {
        FILENO_MAP.put(descriptor.getFileno(), descriptor);
    }

    @Deprecated
    private static void unregisterDescriptor(int aFileno) {
        FILENO_MAP.remove(aFileno);
    }

    @Deprecated
    public static ChannelDescriptor getDescriptorByFileno(int aFileno) {
        return FILENO_MAP.get(aFileno);
    }

    @Deprecated
    public static FileDescriptor getDescriptorFromChannel(Channel channel) {
        return FilenoUtil.getDescriptorFromChannel(channel);
    }

    @Deprecated
    public static int getFilenoFromChannel(Channel channel) {
        return FilenoUtil.filenoFrom(channel);
    }
}