    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.fileupload.util;
    018
    019import java.io.ByteArrayOutputStream;
    020import java.io.IOException;
    021import java.io.InputStream;
    022import java.io.OutputStream;
    023
    024import org.apache.commons.fileupload.InvalidFileNameException;
    025import org.apache.commons.io.IOUtils;
    026
    027/**
    028 * Utility class for working with streams.
    029 */
    030public final class Streams {
    031
    032    /**
    033     * Private constructor, to prevent instantiation.
    034     * This class has only static methods.
    035     */
    036    private Streams() {
    037        // Does nothing
    038    }
    039
    040    /**
    041     * Default buffer size for use in
    042     * {@link #copy(InputStream, OutputStream, boolean)}.
    043     */
    044    private static final int DEFAULT_BUFFER_SIZE = 8192;
    045
    046    /**
    047     * Copies the contents of the given {@link InputStream}
    048     * to the given {@link OutputStream}. Shortcut for
    049     * <pre>
    050     *   copy(pInputStream, pOutputStream, new byte[8192]);
    051     * </pre>
    052     *
    053     * @param inputStream The input stream, which is being read.
    054     * It is guaranteed, that {@link InputStream#close()} is called
    055     * on the stream.
    056     * @param outputStream The output stream, to which data should
    057     * be written. May be null, in which case the input streams
    058     * contents are simply discarded.
    059     * @param closeOutputStream True guarantees, that {@link OutputStream#close()}
    060     * is called on the stream. False indicates, that only
    061     * {@link OutputStream#flush()} should be called finally.
    062     *
    063     * @return Number of bytes, which have been copied.
    064     * @throws IOException An I/O error occurred.
    065     */
    066    public static long copy(InputStream inputStream, OutputStream outputStream, boolean closeOutputStream)
    067            throws IOException {
    068        return copy(inputStream, outputStream, closeOutputStream, new byte[DEFAULT_BUFFER_SIZE]);
    069    }
    070
    071    /**
    072     * Copies the contents of the given {@link InputStream}
    073     * to the given {@link OutputStream}.
    074     *
    075     * @param inputStream The input stream, which is being read.
    076     *   It is guaranteed, that {@link InputStream#close()} is called
    077     *   on the stream.
    078     * @param outputStream The output stream, to which data should
    079     *   be written. May be null, in which case the input streams
    080     *   contents are simply discarded.
    081     * @param closeOutputStream True guarantees, that {@link OutputStream#close()}
    082     *   is called on the stream. False indicates, that only
    083     *   {@link OutputStream#flush()} should be called finally.
    084     * @param buffer Temporary buffer, which is to be used for
    085     *   copying data.
    086     * @return Number of bytes, which have been copied.
    087     * @throws IOException An I/O error occurred.
    088     */
    089    public static long copy(InputStream inputStream,
    090            OutputStream outputStream, boolean closeOutputStream,
    091            byte[] buffer)
    092    throws IOException {
    093        OutputStream out = outputStream;
    094        InputStream in = inputStream;
    095        try {
    096            long total = 0;
    097            for (;;) {
    098                int res = in.read(buffer);
    099                if (res == -1) {
    100                    break;
    101                }
    102                if (res > 0) {
    103                    total += res;
    104                    if (out != null) {
    105                        out.write(buffer, 0, res);
    106                    }
    107                }
    108            }
    109            if (out != null) {
    110                if (closeOutputStream) {
    111                    out.close();
    112                } else {
    113                    out.flush();
    114                }
    115                out = null;
    116            }
    117            in.close();
    118            in = null;
    119            return total;
    120        } finally {
    121            IOUtils.closeQuietly(in);
    122            if (closeOutputStream) {
    123                IOUtils.closeQuietly(out);
    124            }
    125        }
    126    }
    127
    128    /**
    129     * This convenience method allows to read a
    130     * {@link org.apache.commons.fileupload.FileItemStream}'s
    131     * content into a string. The platform's default character encoding
    132     * is used for converting bytes into characters.
    133     *
    134     * @param inputStream The input stream to read.
    135     * @see #asString(InputStream, String)
    136     * @return The streams contents, as a string.
    137     * @throws IOException An I/O error occurred.
    138     */
    139    public static String asString(InputStream inputStream) throws IOException {
    140        ByteArrayOutputStream baos = new ByteArrayOutputStream();
    141        copy(inputStream, baos, true);
    142        return baos.toString();
    143    }
    144
    145    /**
    146     * This convenience method allows to read a
    147     * {@link org.apache.commons.fileupload.FileItemStream}'s
    148     * content into a string, using the given character encoding.
    149     *
    150     * @param inputStream The input stream to read.
    151     * @param encoding The character encoding, typically "UTF-8".
    152     * @see #asString(InputStream)
    153     * @return The streams contents, as a string.
    154     * @throws IOException An I/O error occurred.
    155     */
    156    public static String asString(InputStream inputStream, String encoding) throws IOException {
    157        ByteArrayOutputStream baos = new ByteArrayOutputStream();
    158        copy(inputStream, baos, true);
    159        return baos.toString(encoding);
    160    }
    161
    162    /**
    163     * Checks, whether the given file name is valid in the sense,
    164     * that it doesn't contain any NUL characters. If the file name
    165     * is valid, it will be returned without any modifications. Otherwise,
    166     * an {@link InvalidFileNameException} is raised.
    167     *
    168     * @param fileName The file name to check
    169     * @return Unmodified file name, if valid.
    170     * @throws InvalidFileNameException The file name was found to be invalid.
    171     */
    172    public static String checkFileName(String fileName) {
    173        if (fileName != null  &&  fileName.indexOf('\u0000') != -1) {
    174            // pFileName.replace("\u0000", "\\0")
    175            final StringBuilder sb = new StringBuilder();
    176            for (int i = 0;  i < fileName.length();  i++) {
    177                char c = fileName.charAt(i);
    178                switch (c) {
    179                    case 0:
    180                        sb.append("\\0");
    181                        break;
    182                    default:
    183                        sb.append(c);
    184                        break;
    185                }
    186            }
    187            throw new InvalidFileNameException(fileName,
    188                    "Invalid file name: " + sb);
    189        }
    190        return fileName;
    191    }
    192
    193}