// Copyright 2014 The Bazel Authors. All rights reserved. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package com.google.devtools.build.lib.util; import static java.nio.charset.StandardCharsets.UTF_8; import com.google.common.collect.Iterables; import com.google.common.hash.HashFunction; import com.google.common.hash.Hasher; import com.google.common.hash.Hashing; import com.google.devtools.build.lib.vfs.Path; import com.google.devtools.build.lib.vfs.PathFragment; import java.util.Map; import java.util.UUID; import javax.annotation.Nullable; /** * Simplified wrapper for MD5 message digests. * * @see java.security.MessageDigest */ public final class Fingerprint { private Hasher hasher; private static final HashFunction MD5_HASH_FUNCTION = Hashing.md5(); /** * Creates and initializes a new Hasher. */ public Fingerprint() { reset(); } /** * Completes the hash computation by doing final operations, e.g., padding. * *
This method has the side-effect of resetting the underlying digest computer. * * @return the MD5 digest as a 16-byte array * @see java.security.MessageDigest#digest() */ public byte[] digestAndReset() { byte[] bytes = hasher.hash().asBytes(); reset(); return bytes; } /** * Completes the hash computation and returns the digest as a string. * *
This method has the side-effect of resetting the underlying digest computer.
*
* @return the MD5 digest as a 32-character string of hexadecimal digits
*/
public String hexDigestAndReset() {
String hexDigest = hasher.hash().toString();
reset();
return hexDigest;
}
/**
* Updates the digest with 0 or more bytes.
*
* @param input the array of bytes with which to update the digest
* @see java.security.MessageDigest#update(byte[])
*/
public Fingerprint addBytes(byte[] input) {
hasher.putBytes(input);
return this;
}
/**
* Updates the digest with the specified number of bytes starting at offset.
*
* @param input the array of bytes with which to update the digest
* @param offset the offset into the array
* @param len the number of bytes to use
* @see java.security.MessageDigest#update(byte[], int, int)
*/
public Fingerprint addBytes(byte[] input, int offset, int len) {
hasher.putBytes(input, offset, len);
return this;
}
/**
* Updates the digest with a boolean value.
*/
public Fingerprint addBoolean(boolean input) {
addBytes(new byte[] { (byte) (input ? 1 : 0) });
return this;
}
/**
* Updates the digest with a boolean value, correctly handling null.
*/
public Fingerprint addNullableBoolean(Boolean input) {
addInt(input == null ? -1 : (input.booleanValue() ? 1 : 0));
return this;
}
/**
* Updates the digest with the little-endian bytes of a given int value.
*
* @param input the integer with which to update the digest
*/
public Fingerprint addInt(int input) {
hasher.putInt(input);
return this;
}
/**
* Updates the digest with the little-endian bytes of a given long value.
*
* @param input the long with which to update the digest
*/
public Fingerprint addLong(long input) {
hasher.putLong(input);
return this;
}
/**
* Updates the digest with the little-endian bytes of a given int value, correctly distinguishing
* between null and non-null values.
*
* @param input the integer with which to update the digest
*/
public Fingerprint addNullableInt(@Nullable Integer input) {
if (input == null) {
addInt(0);
} else {
addInt(1);
addInt(input);
}
return this;
}
/**
* Updates the digest with a UUID.
*
* @param uuid the UUID with which to update the digest. Must not be null.
*/
public Fingerprint addUUID(UUID uuid) {
addLong(uuid.getLeastSignificantBits());
addLong(uuid.getMostSignificantBits());
return this;
}
/**
* Updates the digest with a String using its length plus its UTF8 encoded bytes.
*
* @param input the String with which to update the digest
* @see java.security.MessageDigest#update(byte[])
*/
public Fingerprint addString(String input) {
byte[] bytes = input.getBytes(UTF_8);
addInt(bytes.length);
// Note that Hasher#putString() would not include the length of {@code input}.
hasher.putBytes(bytes);
return this;
}
/**
* Updates the digest with a String using its length plus its UTF8 encoded bytes; if the string
* is null, then it uses -1 as the length.
*
* @param input the String with which to update the digest
* @see java.security.MessageDigest#update(byte[])
*/
public Fingerprint addNullableString(@Nullable String input) {
if (input == null) {
addInt(-1);
} else {
addString(input);
}
return this;
}
/**
* Updates the digest with a String using its length and content.
*
* @param input the String with which to update the digest
* @see java.security.MessageDigest#update(byte[])
*/
public Fingerprint addStringLatin1(String input) {
addInt(input.length());
byte[] bytes = new byte[input.length()];
for (int i = 0; i < input.length(); i++) {
bytes[i] = (byte) input.charAt(i);
}
hasher.putBytes(bytes);
return this;
}
/**
* Updates the digest with a Path.
*
* @param input the Path with which to update the digest.
*/
public Fingerprint addPath(Path input) {
addStringLatin1(input.getPathString());
return this;
}
/**
* Updates the digest with a Path.
*
* @param input the Path with which to update the digest.
*/
public Fingerprint addPath(PathFragment input) {
addStringLatin1(input.getPathString());
return this;
}
/**
* Updates the digest with inputs by iterating over them and invoking
* {@code #addString(String)} on each element.
*
* @param inputs the inputs with which to update the digest
*/
public Fingerprint addStrings(Iterable