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.io.input;
018
019import java.io.IOException;
020import java.io.InputStream;
021import java.security.MessageDigest;
022import java.security.NoSuchAlgorithmException;
023import java.security.Provider;
024import java.util.Objects;
025
026import org.apache.commons.io.build.AbstractStreamBuilder;
027
028/**
029 * This class is an example for using an {@link ObservableInputStream}. It creates its own {@link org.apache.commons.io.input.ObservableInputStream.Observer},
030 * which calculates a checksum using a {@link MessageDigest}, for example, a SHA-512 sum.
031 * <p>
032 * To build an instance, see {@link Builder}.
033 * </p>
034 * <p>
035 * See the MessageDigest section in the <a href= "https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#MessageDigest"> Java
036 * Cryptography Architecture Standard Algorithm Name Documentation</a> for information about standard algorithm names.
037 * </p>
038 * <p>
039 * <em>Note</em>: Neither {@link ObservableInputStream}, nor {@link MessageDigest}, are thread safe, so is {@link MessageDigestCalculatingInputStream}.
040 * </p>
041 * @deprecated Use {@link MessageDigestInputStream}.
042 */
043@Deprecated
044public class MessageDigestCalculatingInputStream extends ObservableInputStream {
045
046    /**
047     * Builds a new {@link MessageDigestCalculatingInputStream} instance.
048     * <p>
049     * For example:
050     * </p>
051     * <pre>{@code
052     * MessageDigestCalculatingInputStream s = MessageDigestCalculatingInputStream.builder()
053     *   .setPath(path)
054     *   .setMessageDigest("SHA-512")
055     *   .get();}
056     * </pre>
057     *
058     * @since 2.12.0
059     */
060    public static class Builder extends AbstractStreamBuilder<MessageDigestCalculatingInputStream, Builder> {
061
062        private MessageDigest messageDigest;
063
064        /**
065         * Constructs a new Builder.
066         */
067        public Builder() {
068            try {
069                this.messageDigest = getDefaultMessageDigest();
070            } catch (final NoSuchAlgorithmException e) {
071                // Should not happen.
072                throw new IllegalStateException(e);
073            }
074        }
075
076        /**
077         * Constructs a new instance.
078         * <p>
079         * This builder use the aspects InputStream, OpenOption[], and MessageDigest.
080         * </p>
081         * <p>
082         * You must provide an origin that can be converted to an InputStream by this builder, otherwise, this call will throw an
083         * {@link UnsupportedOperationException}.
084         * </p>
085         *
086         * @return a new instance.
087         * @throws UnsupportedOperationException if the origin cannot provide an InputStream.
088         * @see #getInputStream()
089         */
090        @SuppressWarnings("resource")
091        @Override
092        public MessageDigestCalculatingInputStream get() throws IOException {
093            return new MessageDigestCalculatingInputStream(getInputStream(), messageDigest);
094        }
095
096        /**
097         * Sets the message digest.
098         * <p>
099         * The MD5 cryptographic algorithm is weak and should not be used.
100         * </p>
101         *
102         * @param messageDigest the message digest.
103         */
104        public void setMessageDigest(final MessageDigest messageDigest) {
105            this.messageDigest = messageDigest;
106        }
107
108        /**
109         * Sets the name of the name of the message digest algorithm.
110         * <p>
111         * The MD5 cryptographic algorithm is weak and should not be used.
112         * </p>
113         *
114         * @param algorithm the name of the algorithm. See the MessageDigest section in the
115         *                  <a href= "https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#MessageDigest"> Java Cryptography
116         *                  Architecture Standard Algorithm Name Documentation</a> for information about standard algorithm names.
117         * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation for the specified algorithm.
118         */
119        public void setMessageDigest(final String algorithm) throws NoSuchAlgorithmException {
120            this.messageDigest = MessageDigest.getInstance(algorithm);
121        }
122
123    }
124
125    /**
126     * Maintains the message digest.
127     */
128    public static class MessageDigestMaintainingObserver extends Observer {
129        private final MessageDigest messageDigest;
130
131        /**
132         * Constructs an MessageDigestMaintainingObserver for the given MessageDigest.
133         *
134         * @param messageDigest the message digest to use
135         * @throws NullPointerException if messageDigest is null.
136         */
137        public MessageDigestMaintainingObserver(final MessageDigest messageDigest) {
138            this.messageDigest = Objects.requireNonNull(messageDigest, "messageDigest");
139        }
140
141        @Override
142        public void data(final byte[] input, final int offset, final int length) throws IOException {
143            messageDigest.update(input, offset, length);
144        }
145
146        @Override
147        public void data(final int input) throws IOException {
148            messageDigest.update((byte) input);
149        }
150    }
151
152    /**
153     * The default message digest algorithm.
154     * <p>
155     * The MD5 cryptographic algorithm is weak and should not be used.
156     * </p>
157     */
158    private static final String DEFAULT_ALGORITHM = "MD5";
159
160    /**
161     * Constructs a new {@link Builder}.
162     *
163     * @return a new {@link Builder}.
164     * @since 2.12.0
165     */
166    public static Builder builder() {
167        return new Builder();
168    }
169
170    /**
171     * Gets a MessageDigest object that implements the default digest algorithm.
172     *
173     * @return a Message Digest object that implements the default algorithm.
174     * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation.
175     * @see Provider
176     */
177    static MessageDigest getDefaultMessageDigest() throws NoSuchAlgorithmException {
178        return MessageDigest.getInstance(DEFAULT_ALGORITHM);
179    }
180
181    private final MessageDigest messageDigest;
182
183    /**
184     * Constructs a new instance, which calculates a signature on the given stream, using a {@link MessageDigest} with the "MD5" algorithm.
185     * <p>
186     * The MD5 algorithm is weak and should not be used.
187     * </p>
188     *
189     * @param inputStream the stream to calculate the message digest for
190     * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation for the specified algorithm.
191     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
192     */
193    @Deprecated
194    public MessageDigestCalculatingInputStream(final InputStream inputStream) throws NoSuchAlgorithmException {
195        this(inputStream, getDefaultMessageDigest());
196    }
197
198    /**
199     * Constructs a new instance, which calculates a signature on the given stream, using the given {@link MessageDigest}.
200     * <p>
201     * The MD5 cryptographic algorithm is weak and should not be used.
202     * </p>
203     *
204     * @param inputStream   the stream to calculate the message digest for
205     * @param messageDigest the message digest to use
206     * @throws NullPointerException if messageDigest is null.
207     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
208     */
209    @Deprecated
210    public MessageDigestCalculatingInputStream(final InputStream inputStream, final MessageDigest messageDigest) {
211        super(inputStream, new MessageDigestMaintainingObserver(messageDigest));
212        this.messageDigest = messageDigest;
213    }
214
215    /**
216     * Constructs a new instance, which calculates a signature on the given stream, using a {@link MessageDigest} with the given algorithm.
217     * <p>
218     * The MD5 cryptographic algorithm is weak and should not be used.
219     * </p>
220     *
221     * @param inputStream the stream to calculate the message digest for
222     * @param algorithm   the name of the algorithm requested. See the MessageDigest section in the
223     *                    <a href= "https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#MessageDigest"> Java Cryptography
224     *                    Architecture Standard Algorithm Name Documentation</a> for information about standard algorithm names.
225     * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation for the specified algorithm.
226     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
227     */
228    @Deprecated
229    public MessageDigestCalculatingInputStream(final InputStream inputStream, final String algorithm) throws NoSuchAlgorithmException {
230        this(inputStream, MessageDigest.getInstance(algorithm));
231    }
232
233    /**
234     * Gets the {@link MessageDigest}, which is being used for generating the checksum.
235     * <p>
236     * <em>Note</em>: The checksum will only reflect the data, which has been read so far. This is probably not, what you expect. Make sure, that the complete
237     * data has been read, if that is what you want. The easiest way to do so is by invoking {@link #consume()}.
238     * </p>
239     *
240     * @return the message digest used
241     */
242    public MessageDigest getMessageDigest() {
243        return messageDigest;
244    }
245}