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/*
 * Copyright (c) 1997, 2023 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.eclipse.angus.mail.util;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.logging.Level;

/**
 * This class is a subclass of DataOutputStream that copies the
 * data being written into the DataOutputStream into another output
 * stream. This class is used here to provide a debug trace of the
 * stuff thats being written out into the DataOutputStream.
 *
 * @author John Mani
 */

public class TraceOutputStream extends FilterOutputStream {
    private boolean trace = false;
    private boolean quote = false;
    private OutputStream traceOut;

    /**
     * Creates an output stream filter built on top of the specified
     * underlying output stream.
     *
     * @param out the underlying output stream.
     * @param    logger    log trace here
     */
    public TraceOutputStream(OutputStream out, MailLogger logger) {
        super(out);
        this.trace = logger.isLoggable(Level.FINEST);
        this.traceOut = new LogOutputStream(logger);
        ;
    }

    /**
     * Creates an output stream filter built on top of the specified
     * underlying output stream.
     *
     * @param out the underlying output stream.
     * @param    traceOut    the trace stream.
     */
    public TraceOutputStream(OutputStream out, OutputStream traceOut) {
        super(out);
        this.traceOut = traceOut;
    }

    /**
     * Set the trace mode.
     *
     * @param    trace    the trace mode
     */
    public void setTrace(boolean trace) {
        this.trace = trace;
    }

    /**
     * Set quote mode.
     *
     * @param    quote    the quote mode
     */
    public void setQuote(boolean quote) {
        this.quote = quote;
    }

    /**
     * Writes the specified byte to this output stream.
     * Writes out the byte into the trace stream if the trace mode
     * is true
     *
     * @param    b    the byte to write
     * @exception IOException    for I/O errors
     */
    @Override
    public void write(int b) throws IOException {
        if (trace) {
            if (quote)
                writeByte(b);
            else
                traceOut.write(b);
        }
        out.write(b);
    }

    /**
     * Writes b.length bytes to this output stream.
     * Writes out the bytes into the trace stream if the trace
     * mode is true
     *
     * @param    b    bytes to write
     * @param    off    offset in array
     * @param    len    number of bytes to write
     * @exception IOException    for I/O errors
     */
    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        if (trace) {
            if (quote) {
                for (int i = 0; i < len; i++)
                    writeByte(b[off + i]);
            } else
                traceOut.write(b, off, len);
        }
        out.write(b, off, len);
    }

    /**
     * Write a byte in a way that every byte value is printable ASCII.
     */
    private final void writeByte(int b) throws IOException {
        b &= 0xff;
        if (b > 0x7f) {
            traceOut.write('M');
            traceOut.write('-');
            b &= 0x7f;
        }
        if (b == '\r') {
            traceOut.write('\\');
            traceOut.write('r');
        } else if (b == '\n') {
            traceOut.write('\\');
            traceOut.write('n');
            traceOut.write('\n');
        } else if (b == '\t') {
            traceOut.write('\\');
            traceOut.write('t');
        } else if (b < ' ') {
            traceOut.write('^');
            traceOut.write('@' + b);
        } else {
            traceOut.write(b);
        }
    }
}