org.apache.hadoop.fs.redfish.RedfishDataInputStream.java Source code

Introduction

Here is the source code for org.apache.hadoop.fs.redfish.RedfishDataInputStream.java

Source

/*
 * Copyright 2011-2012 the Redfish authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.fs.redfish;

import java.io.*;
import java.net.*;

import org.apache.commons.logging.Log;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PositionedReadable;
import org.apache.hadoop.fs.Seekable;

class RedfishDataInputStream extends InputStream implements Seekable, PositionedReadable, Closeable {
    private long m_ofe;

    static {
        try {
            System.loadLibrary("hfishc");
        } catch (UnsatisfiedLinkError e) {
            e.printStackTrace();
            System.err.println("Unable to load hfishc: " + System.getProperty("java.library.path"));
            System.exit(1);
        }
    }

    private RedfishDataInputStream(long ofe) {
        m_ofe = ofe;
    }

    /* This finalizer is intended to free the (small!) amount of memory used by
     * the redfish_file data structure of a closed file.  It also destroys the
     * pthread mutex used to make the rest of the functions thread-safe.
     *
     * Please call close() explicitly to close files.  This it NOT intended as a
     * replacement for that function.
     * */
    protected void finalize() throws Throwable {
    }

    {
        this.redfishFree();
    }

    @Override
    public boolean markSupported() {
        return false;
    }

    @Override
    public int read() throws IOException {
        int amt;

        /* The oh-so-useful "read a single byte" method */
        byte[] buf = new byte[1];
        amt = redfishRead(buf, 0, 1);
        if (amt != 1)
            return -1;
        return (int) (buf[0] & 0xff);
    }

    @Override
    public int read(byte[] buf) throws IOException {
        return redfishRead(buf, 0, buf.length);
    }

    @Override
    public int read(byte[] buf, int off, int len) throws IOException {
        return redfishRead(buf, off, len);
    }

    @Override
    public int read(long pos, byte[] buf, int off, int len) throws IOException {
        return redfishPread(pos, buf, off, len);
    }

    @Override
    public void readFully(long pos, byte[] buf, int off, int len) throws IOException {
        int nread = redfishPread(pos, buf, off, len);
        if (nread < len) {
            throw new EOFException("End of file reached before reading fully.");
        }
    }

    @Override
    public void readFully(long pos, byte[] buf) throws IOException {
        readFully(pos, buf, 0, buf.length);
    }

    @Override
    public boolean seekToNewSource(long targetPos) throws IOException {
        /* Redfish handles failover between chunk replicas internally, so this
         * method should be unneeded? */
        return false;
    }

    @Override
    public native int available() throws IOException;

    private native int redfishRead(byte[] buf, int boff, int blen) throws IOException;

    private native int redfishPread(long off, byte[] buf, int boff, int blen) throws IOException;

    @Override
    public native void close() throws IOException;

    private native void free();

    @Override
    public native void seek(long off) throws IOException;

    @Override
    public native long getPos() throws IOException;

    private native void redfishFree();
}