/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.rmi.transport.proxy;

import java.io.*;

import sun.rmi.runtime.Log;

/**

 * The HttpInputStream class assists the HttpSendSocket and HttpReceiveSocket

 * classes by filtering out the header for the message as well as any

 * data after its proper content length.

 */

class HttpInputStream extends FilterInputStream {

    /** bytes remaining to be read from proper content of message */

    protected int bytesLeft;

    /** bytes remaining to be read at time of last mark */

    protected int bytesLeftAtMark;

    /**

     * Create new filter on a given input stream.

     * @param in the InputStream to filter from

     */

    public HttpInputStream(InputStream in) throws IOException

    {

        super(in);

        if (in.markSupported())

            in.mark(0); // prevent resetting back to old marks

        // pull out header, looking for content length

        DataInputStream dis = new DataInputStream(in);

        String key = "Content-length:".toLowerCase();

        boolean contentLengthFound = false;

        String line;

        do {

            line = dis.readLine();

            if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {

                RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,

                    "received header line: \"" + line + "\"");

            }

            if (line == null)

                throw new EOFException();

            if (line.toLowerCase().startsWith(key)) {

            }

            // The idea here is to go past the first blank line.

            // Some DataInputStream.readLine() documentation specifies that

            // it does include the line-terminating character(s) in the

            // returned string, but it actually doesn't, so we'll cover

            // all cases here...

        } while ((line.length() != 0) &&

                 (line.charAt(0) != '\r') && (line.charAt(0) != '\n'));

        if (!contentLengthFound || bytesLeft < 0) {

            // This really shouldn't happen, but if it does, shoud we fail??

            // For now, just give up and let a whole lot of bytes through...

            bytesLeft = Integer.MAX_VALUE;

        }

        bytesLeftAtMark = bytesLeft;

        if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {

            RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,

                "content length: " + bytesLeft);

        }

    }

    /**

     * Returns the number of bytes that can be read with blocking.

     * Make sure that this does not exceed the number of bytes remaining

     * in the proper content of the message.

     */

    public int available() throws IOException

    {

        int bytesAvailable = in.available();

        if (bytesAvailable > bytesLeft)

            bytesAvailable = bytesLeft;

        return bytesAvailable;

    }

    /**

     * Read a byte of data from the stream.  Make sure that one is available

     * from the proper content of the message, else -1 is returned to

     * indicate to the user that the end of the stream has been reached.

     */

    public int read() throws IOException

    {

        if (bytesLeft > 0) {

            int data = in.read();

            if (data != -1)

                -- bytesLeft;

            if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {

                RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,

                   "received byte: '" +

                    ((data & 0x7F) < ' ' ? " " : String.valueOf((char) data)) +

                    "' " + data);

            }

            return data;

        }

        else {

            RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,

                                                "read past content length");

            return -1;

        }

    }

    public int read(byte b[], int off, int len) throws IOException

    {

        if (bytesLeft == 0 && len > 0) {

            RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,

                                                "read past content length");

            return -1;

        }

        if (len > bytesLeft)

            len = bytesLeft;

        int bytesRead = in.read(b, off, len);

        bytesLeft -= bytesRead;

        if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {

            RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,

                "read " + bytesRead + " bytes, " + bytesLeft + " remaining");

        }

        return bytesRead;

    }

    /**

     * Mark the current position in the stream (for future calls to reset).

     * Remember where we are within the proper content of the message, so

     * that a reset method call can recreate our state properly.

     * @param readlimit how many bytes can be read before mark becomes invalid

     */

    public void mark(int readlimit)

    {

        in.mark(readlimit);

        if (in.markSupported())

            bytesLeftAtMark = bytesLeft;

    }

    /**

     * Repositions the stream to the last marked position.  Make sure to

     * adjust our position within the proper content accordingly.

     */

    public void reset() throws IOException

    {

        in.reset();

        bytesLeft = bytesLeftAtMark;

    }

    /**

     * Skips bytes of the stream.  Make sure to adjust our

     * position within the proper content accordingly.

     * @param n number of bytes to be skipped

     */

    public long skip(long n) throws IOException

    {

        if (n > bytesLeft)

            n = bytesLeft;

        long bytesSkipped = in.skip(n);

        bytesLeft -= bytesSkipped;

        return bytesSkipped;

    }

}