org.gradle.caching.internal.DefaultBuildCacheHasher.java Source code

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Here is the source code for org.gradle.caching.internal.DefaultBuildCacheHasher.java

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/*
 * Copyright 2017 the original author or authors.
 *
 * 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 org.gradle.caching.internal;

import com.google.common.base.Charsets;
import com.google.common.hash.HashCode;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import org.apache.commons.lang.SerializationUtils;

import java.io.Serializable;
import java.lang.reflect.Array;
import java.math.BigInteger;
import java.util.Map;

/**
 * A hasher used for build cache keys.
 *
 * In order to avoid collisions we prepend the length of the next bytes to the underlying
 * hasher (see this <a href="http://crypto.stackexchange.com/a/10065">answer</a> on stackexchange).
 */
public class DefaultBuildCacheHasher implements BuildCacheHasher {
    private final Hasher hasher = Hashing.md5().newHasher();

    @Override
    public DefaultBuildCacheHasher putByte(byte b) {
        hasher.putInt(1);
        hasher.putByte(b);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putBytes(byte[] bytes) {
        hasher.putInt(bytes.length);
        hasher.putBytes(bytes);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putBytes(byte[] bytes, int off, int len) {
        hasher.putInt(len);
        hasher.putBytes(bytes, off, len);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putInt(int i) {
        hasher.putInt(4);
        hasher.putInt(i);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putLong(long l) {
        hasher.putInt(8);
        hasher.putLong(l);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putDouble(double d) {
        hasher.putInt(8);
        hasher.putDouble(d);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putBoolean(boolean b) {
        hasher.putInt(1);
        hasher.putBoolean(b);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putString(CharSequence charSequence) {
        hasher.putInt(charSequence.length());
        hasher.putString(charSequence, Charsets.UTF_8);
        return this;
    }

    @Override
    public DefaultBuildCacheHasher putObject(Object value) {
        if (value == null) {
            this.putString("$NULL");
            return this;
        }

        if (value.getClass().isArray()) {
            this.putString("Array");
            for (int idx = 0, len = Array.getLength(value); idx < len; idx++) {
                this.putInt(idx);
                this.putObject(Array.get(value, idx));
            }
            return this;
        }

        if (value instanceof Iterable) {
            this.putString("Iterable");
            int idx = 0;
            for (Object elem : (Iterable<?>) value) {
                this.putInt(idx);
                this.putObject(elem);
                idx++;
            }
            return this;
        }

        if (value instanceof Map) {
            this.putString("Map");
            int idx = 0;
            for (Map.Entry<?, ?> entry : ((Map<?, ?>) value).entrySet()) {
                this.putInt(idx);
                this.putObject(entry.getKey());
                this.putObject(entry.getValue());
                idx++;
            }
            return this;
        }

        if (value instanceof Boolean) {
            this.putBoolean((Boolean) value);
        } else if (value instanceof Long) {
            this.putLong((Long) value);
        } else if (value instanceof Integer) {
            this.putInt((Integer) value);
        } else if (value instanceof Short) {
            this.putInt((Short) value);
        } else if (value instanceof Byte) {
            this.putInt((Byte) value);
        } else if (value instanceof Double) {
            this.putDouble((Double) value);
        } else if (value instanceof Float) {
            this.putDouble((Float) value);
        } else if (value instanceof BigInteger) {
            this.putBytes(((BigInteger) value).toByteArray());
        } else if (value instanceof CharSequence) {
            this.putString((CharSequence) value);
        } else if (value instanceof Enum) {
            this.putString(value.getClass().getName());
            this.putString(((Enum) value).name());
        } else {
            byte[] bytes = SerializationUtils.serialize((Serializable) value);
            this.putBytes(bytes);
        }
        return this;
    }

    @Override
    public HashCode hash() {
        return hasher.hash();
    }
}