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, use {@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 *
042 * @see Builder
043 * @deprecated Use {@link MessageDigestInputStream}.
044 */
045@Deprecated
046public class MessageDigestCalculatingInputStream extends ObservableInputStream {
047
048    // @formatter:off
049    /**
050     * Builds a new {@link MessageDigestCalculatingInputStream}.
051     *
052     * <p>
053     * For example:
054     * </p>
055     * <pre>{@code
056     * MessageDigestCalculatingInputStream s = MessageDigestCalculatingInputStream.builder()
057     *   .setPath(path)
058     *   .setMessageDigest("SHA-512")
059     *   .get();}
060     * </pre>
061     *
062     * @see #get()
063     * @since 2.12.0
064     */
065    // @formatter:on
066    public static class Builder extends AbstractStreamBuilder<MessageDigestCalculatingInputStream, Builder> {
067
068        private MessageDigest messageDigest;
069
070        /**
071         * Constructs a new {@link Builder}.
072         */
073        public Builder() {
074            try {
075                this.messageDigest = getDefaultMessageDigest();
076            } catch (final NoSuchAlgorithmException e) {
077                // Should not happen.
078                throw new IllegalStateException(e);
079            }
080        }
081
082        /**
083         * Builds a new {@link MessageDigestCalculatingInputStream}.
084         * <p>
085         * You must set input that supports {@link #getInputStream()}, otherwise, this method throws an exception.
086         * </p>
087         * <p>
088         * This builder use the following aspects:
089         * </p>
090         * <ul>
091         * <li>{@link #getPath()}</li>
092         * <li>{@link MessageDigest}</li>
093         * </ul>
094         *
095         * @return a new instance.
096         * @throws NullPointerException if messageDigest is null.
097         * @throws IllegalStateException         if the {@code origin} is {@code null}.
098         * @throws UnsupportedOperationException if the origin cannot be converted to an {@link InputStream}.
099         * @throws IOException                   if an I/O error occurs.
100         * @see #getInputStream()
101         */
102        @SuppressWarnings("resource")
103        @Override
104        public MessageDigestCalculatingInputStream get() throws IOException {
105            return new MessageDigestCalculatingInputStream(getInputStream(), messageDigest);
106        }
107
108        /**
109         * Sets the message digest.
110         * <p>
111         * The MD5 cryptographic algorithm is weak and should not be used.
112         * </p>
113         *
114         * @param messageDigest the message digest.
115         */
116        public void setMessageDigest(final MessageDigest messageDigest) {
117            this.messageDigest = messageDigest;
118        }
119
120        /**
121         * Sets the name of the name of the message digest algorithm.
122         * <p>
123         * The MD5 cryptographic algorithm is weak and should not be used.
124         * </p>
125         *
126         * @param algorithm the name of the algorithm. See the MessageDigest section in the
127         *                  <a href= "https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#MessageDigest"> Java Cryptography
128         *                  Architecture Standard Algorithm Name Documentation</a> for information about standard algorithm names.
129         * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation for the specified algorithm.
130         */
131        public void setMessageDigest(final String algorithm) throws NoSuchAlgorithmException {
132            this.messageDigest = MessageDigest.getInstance(algorithm);
133        }
134
135    }
136
137    /**
138     * Maintains the message digest.
139     */
140    public static class MessageDigestMaintainingObserver extends Observer {
141        private final MessageDigest messageDigest;
142
143        /**
144         * Constructs an MessageDigestMaintainingObserver for the given MessageDigest.
145         *
146         * @param messageDigest the message digest to use
147         * @throws NullPointerException if messageDigest is null.
148         */
149        public MessageDigestMaintainingObserver(final MessageDigest messageDigest) {
150            this.messageDigest = Objects.requireNonNull(messageDigest, "messageDigest");
151        }
152
153        @Override
154        public void data(final byte[] input, final int offset, final int length) throws IOException {
155            messageDigest.update(input, offset, length);
156        }
157
158        @Override
159        public void data(final int input) throws IOException {
160            messageDigest.update((byte) input);
161        }
162    }
163
164    /**
165     * The default message digest algorithm.
166     * <p>
167     * The MD5 cryptographic algorithm is weak and should not be used.
168     * </p>
169     */
170    private static final String DEFAULT_ALGORITHM = "MD5";
171
172    /**
173     * Constructs a new {@link Builder}.
174     *
175     * @return a new {@link Builder}.
176     * @since 2.12.0
177     */
178    public static Builder builder() {
179        return new Builder();
180    }
181
182    /**
183     * Gets a MessageDigest object that implements the default digest algorithm.
184     *
185     * @return a Message Digest object that implements the default algorithm.
186     * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation.
187     * @see Provider
188     */
189    static MessageDigest getDefaultMessageDigest() throws NoSuchAlgorithmException {
190        return MessageDigest.getInstance(DEFAULT_ALGORITHM);
191    }
192
193    private final MessageDigest messageDigest;
194
195    /**
196     * Constructs a new instance, which calculates a signature on the given stream, using a {@link MessageDigest} with the "MD5" algorithm.
197     * <p>
198     * The MD5 algorithm is weak and should not be used.
199     * </p>
200     *
201     * @param inputStream the stream to calculate the message digest for
202     * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation for the specified algorithm.
203     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
204     */
205    @Deprecated
206    public MessageDigestCalculatingInputStream(final InputStream inputStream) throws NoSuchAlgorithmException {
207        this(inputStream, getDefaultMessageDigest());
208    }
209
210    /**
211     * Constructs a new instance, which calculates a signature on the given stream, using the given {@link MessageDigest}.
212     * <p>
213     * The MD5 cryptographic algorithm is weak and should not be used.
214     * </p>
215     *
216     * @param inputStream   the stream to calculate the message digest for
217     * @param messageDigest the message digest to use
218     * @throws NullPointerException if messageDigest is null.
219     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
220     */
221    @Deprecated
222    public MessageDigestCalculatingInputStream(final InputStream inputStream, final MessageDigest messageDigest) {
223        super(inputStream, new MessageDigestMaintainingObserver(messageDigest));
224        this.messageDigest = messageDigest;
225    }
226
227    /**
228     * Constructs a new instance, which calculates a signature on the given stream, using a {@link MessageDigest} with the given algorithm.
229     * <p>
230     * The MD5 cryptographic algorithm is weak and should not be used.
231     * </p>
232     *
233     * @param inputStream the stream to calculate the message digest for
234     * @param algorithm   the name of the algorithm requested. See the MessageDigest section in the
235     *                    <a href= "https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#MessageDigest"> Java Cryptography
236     *                    Architecture Standard Algorithm Name Documentation</a> for information about standard algorithm names.
237     * @throws NoSuchAlgorithmException if no Provider supports a MessageDigestSpi implementation for the specified algorithm.
238     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
239     */
240    @Deprecated
241    public MessageDigestCalculatingInputStream(final InputStream inputStream, final String algorithm) throws NoSuchAlgorithmException {
242        this(inputStream, MessageDigest.getInstance(algorithm));
243    }
244
245    /**
246     * Gets the {@link MessageDigest}, which is being used for generating the checksum.
247     * <p>
248     * <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
249     * data has been read, if that is what you want. The easiest way to do so is by invoking {@link #consume()}.
250     * </p>
251     *
252     * @return the message digest used
253     */
254    public MessageDigest getMessageDigest() {
255        return messageDigest;
256    }
257}