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A bundle project producing JAX-RS RI bundles. The primary artifact is an "all-in-one" OSGi-fied JAX-RS RI bundle (jaxrs-ri.jar). Attached to that are two compressed JAX-RS RI archives. The first archive (jaxrs-ri.zip) consists of binary RI bits and contains the API jar (under "api" directory), RI libraries (under "lib" directory) as well as all external RI dependencies (under "ext" directory). The secondary archive (jaxrs-ri-src.zip) contains buildable JAX-RS RI source bundle and contains the API jar (under "api" directory), RI sources (under "src" directory) as well as all external RI dependencies (under "ext" directory). The second archive also contains "build.xml" ANT script that builds the RI sources. To build the JAX-RS RI simply unzip the archive, cd to the created jaxrs-ri directory and invoke "ant" from the command line.

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/*
 * Copyright (c) 2013, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.jersey.internal.util.collection;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;

import org.glassfish.jersey.internal.LocalizationMessages;

/**
 * An {@link java.io.InputStream} backed by a queue of {@link java.nio.ByteBuffer byte buffers}
 * to be read.
 * 

 * This input stream serves as a bridging inbound I/O component between a blocking upper I/O layer
 * and an underlying non-blocking I/O layer. In addition to the blocking {@code InputStream.read} operations,
 * this input stream provides the non-blocking {@code tryRead} counterparts.
 * 

 *
 * @author Marek Potociar
 */
public final class ByteBufferInputStream extends NonBlockingInputStream {

    /**
     * Constant buffer indicating EOF.
     */
    private static final ByteBuffer EOF = ByteBuffer.wrap(new byte[] {});

    /**
     * Read-side EOF flag. Does not have to be volatile, it is transient and only accessed from the reader thread.
     */
    private boolean eof = false;
    /**
     * Currently read byte buffer.
     */
    private ByteBuffer current;
    /**
     * Queue of byte buffers to be read.
     */
    private final BlockingQueue buffers;
    /**
     * Content represents the buffer queue status.
     *
     * null = open, POISON_PILL = closed, Throwable = closed with error
     */
    private final AtomicReference queueStatus = new AtomicReference(null);
    /**
     * Closed flag.
     */
    private final AtomicBoolean closed = new AtomicBoolean(false);

    /**
     * Create a new input stream that is backed by a a queue of {@link java.nio.ByteBuffer byte buffers}
     * to be read.
     */
    public ByteBufferInputStream() {
        this.buffers = new LinkedTransferQueue<>();
        this.current = null;
    }

    private boolean fetchChunk(final boolean block) throws InterruptedException {
        if (eof) {
            return false;
        }

        // Read until no buffers available (poll returned null)
        // or until a non-empty buffer or EOF is reached.
        do {
            if (closed.get()) {
                current = EOF;
                break;
            }

            current = (block) ? buffers.take() : buffers.poll();
        } while (current != null && current != EOF && !current.hasRemaining());

        eof = current == EOF;
        return !eof;
    }

    private void checkNotClosed() throws IOException {
        if (closed.get()) {
            throw new IOException(LocalizationMessages.INPUT_STREAM_CLOSED());
        }
    }

    private void checkThrowable() throws IOException {
        final Object o = queueStatus.get();
        if (o != null && o != EOF) { // should be faster than instanceof
            // if not null or EOF, then it must be Throwable
            if (queueStatus.compareAndSet(o, EOF)) {
                // clear throwable flag and throw exception
                try {
                    throw new IOException((Throwable) o);
                } finally {
                    close();
                }
            }
        }
    }

    @Override
    public int available() throws IOException {
        if (eof || closed.get()) {
            checkThrowable();
            return 0;
        }

        int available = 0;
        if (current != null && current.hasRemaining()) {
            available = current.remaining();
        }
        for (final ByteBuffer buffer : buffers) {
            if (buffer == EOF) {
                break;
            }
            available += buffer.remaining();
        }

        checkThrowable();
        return closed.get() ? 0 : available;
    }

    @Override
    public int read() throws IOException {
        return tryRead(true);
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        return tryRead(b, off, len, true);
    }

    public int tryRead() throws IOException {
        return tryRead(false);
    }

    @Override
    public int tryRead(final byte[] b) throws IOException {
        return tryRead(b, 0, b.length);
    }

    @Override
    public int tryRead(final byte[] b, final int off, final int len) throws IOException {
        return tryRead(b, off, len, false);
    }

    @Override
    public void close() throws IOException {
        if (closed.compareAndSet(false, true)) {
            closeQueue();
            // we can now safely clear the queue - any blocking read waiting for a buffer
            // has been resumed by the EOF buffer
            buffers.clear();
        }
        checkThrowable();
    }

    /**
     * Put the {@code ByteBuffer} to the internal queue to be available for reading from the stream.
     *
     * 

     * If the sink is open, the method {@link BlockingQueue#put(Object) puts the buffer} into an internal
     * byte buffer read queue , waiting if necessary for space to become available. Then the method returns
     * {@code true} to indicate the buffer has been successfully queued. In case the internal read queue has been
     * {@link #closeQueue() closed} already, the method simply returns {@code false} without registering
     * the buffer in the closed queue.
     * 

     *
     * @param src the source buffer to be registered in the byte buffer read queue.
     * @return {@code true} if the byte buffer has been successfully put in the read queue,
     *         {@code false} if the read queue has been closed.
     * @throws InterruptedException in case the put operation has been interrupted.
     */
    public boolean put(final ByteBuffer src) throws InterruptedException {
        if (queueStatus.get() == null) {
            buffers.put(src);
            return true;
        }
        return false;
    }

    /**
     * Closes the byte buffer sink of this input stream to indicate that writing to the stream
     * has been finished.
     * 

     * If the sink has already been closed then this method returns immediately. Otherwise the
     * sink is marked as closed and no more data can be written to it.
     * 

     */
    public void closeQueue() {
        if (queueStatus.compareAndSet(null, EOF)) {
            try {
                buffers.put(EOF);
            } catch (final InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }

    /**
     * Closes the byte buffer sink of this input stream to indicate that writing to the stream
     * has been finished due to a throwable.
     *
     * The throwable set by this method will be propagated to the reader thread when a new attempt
     * to read bytes is made.
     * 

     * If the sink has already been closed then this method only sets the throwable in the stream and
     * then returns immediately. Otherwise the sink is also marked as closed and no more data can be
     * written to it.
     * 

     *
     * @param throwable throwable that is set in the stream. It will be thrown by the stream in case
     *                  an attempt to read more data or check available bytes is made.
     */
    public void closeQueue(final Throwable throwable) {
        if (queueStatus.compareAndSet(null, throwable)) {
            try {
                buffers.put(EOF);
            } catch (final InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }

    private int tryRead(final byte[] b, final int off, final int len, boolean block) throws IOException {
        checkThrowable();
        checkNotClosed();

        if (b == null) {
            throw new NullPointerException();
        } else if (off < 0 || len < 0 || len > b.length - off) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
            return 0;
        }

        if (eof) {
            return -1;
        }

        int i = 0;
        while (i < len) {
            if (current != null && current.hasRemaining()) {
                final int available = current.remaining();
                if (available < len - i) {
                    current.get(b, off + i, available);
                    i += available;
                } else {
                    current.get(b, off + i, len - i);
                    return len;
                }
            } else {
                try {
                    if (!fetchChunk(block) || current == null) {
                        break;  // eof or no data
                    }
                } catch (final InterruptedException e) {
                    Thread.currentThread().interrupt();
                    if (block) {
                        throw new IOException(e);
                    }
                }
            }
        }

        return i == 0 && eof ? -1 : i;
    }

    private int tryRead(boolean block) throws IOException {
        checkThrowable();
        checkNotClosed();

        if (eof) {
            return -1;
        }

        if (current != null && current.hasRemaining()) {
            return current.get() & 0xFF;
        }

        try {
            // try to fetch, but don't block && check if something has been fetched
            if (fetchChunk(block) && current != null) {
                return current.get() & 0xFF;
            } else if (block) {
                return -1;
            }
        } catch (final InterruptedException e) {
            Thread.currentThread().interrupt();
            if (block) {
                throw new IOException(e);
            }
        }

        return (eof) ? -1 : NOTHING;
    }
}
 















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