/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.apache.shiro.crypto.hash;

 import org.apache.shiro.util.ByteSource;

 /**

  * A {@code HashRequest} is composed of data that will be used by a {@link HashService} to compute a hash (aka

  * 'digest').  While you can instantiate a concrete {@code HashRequest} class directly, most will find using the

  * {@link HashRequest.Builder} more convenient.

  *

  * @see HashRequest.Builder

  * @since 1.2

  */

 public interface HashRequest {

     /**

      * Returns the source data that will be hashed by a {@link HashService}. For example, this might be a

      * {@code ByteSource} representation of a password, or file, etc.

      *

      * @return the source data that will be hashed by a {@link HashService}.

      */

     ByteSource getSource();

     /**

      * Returns a salt to be used by the {@link HashService} during hash computation, or {@code null} if no salt is

      * provided as part of the request.

      * <p/>

      * Note that a {@code null} value does not necessarily mean a salt won't be used at all - it just

      * means that the request didn't include one.  The servicing {@link HashService} is free to provide a salting

      * strategy for a request, even if the request did not specify one.

      *

      * @return a salt to be used by the {@link HashService} during hash computation, or {@code null} if no salt is

      *         provided as part of the request.

      */

     ByteSource getSalt();

     /**

      * Returns the number of requested hash iterations to be performed when computing the final {@code Hash} result.

      * A non-positive (0 or less) indicates that the {@code HashService}'s default iteration configuration should

      * be used.  A positive value overrides the {@code HashService}'s configuration for a single request.

      * <p/>

      * Note that a {@code HashService} is free to ignore this number if it determines the number is not sufficient

      * to meet a desired level of security.

      *

      * @return the number of requested hash iterations to be performed when computing the final {@code Hash} result.

      */

     int getIterations();

     /**

      * Returns the name of the hash algorithm the {@code HashService} should use when computing the {@link Hash}, or

      * {@code null} if the default algorithm configuration of the {@code HashService} should be used.  A non-null value

      * overrides the {@code HashService}'s configuration for a single request.

      * <p/>

      * Note that a {@code HashService} is free to ignore this value if it determines that the algorithm is not

      * sufficient to meet a desired level of security.

      *

      * @return the name of the hash algorithm the {@code HashService} should use when computing the {@link Hash}, or

      *         {@code null} if the default algorithm configuration of the {@code HashService} should be used.

      */

     String getAlgorithmName();

     /**

      * A Builder class representing the Builder design pattern for constructing {@link HashRequest} instances.

      *

      * @see SimpleHashRequest

      * @since 1.2

      */

     public static class Builder {

         private ByteSource source;

         private ByteSource salt;

         private int iterations;

         private String algorithmName;

         /**

          * Default no-arg constructor.

          */

         public Builder() {

             this.iterations = 0;

         }

         /**

          * Sets the source data that will be hashed by a {@link HashService}. For example, this might be a

          * {@code ByteSource} representation of a password, or file, etc.

          *

          * @param source the source data that will be hashed by a {@link HashService}.

          * @return this {@code Builder} instance for method chaining.

          * @see HashRequest#getSource()

          * @see #setSource(Object)

          */

         public Builder setSource(ByteSource source) {

             this.source = source;

             return this;

         }

         /**

          * Sets the source data that will be hashed by a {@link HashService}.

          * <p/>

          * This is a convenience alternative to {@link #setSource(ByteSource)}: it will attempt to convert the

          * argument into a {@link ByteSource} instance using Shiro's default conversion heuristics

          * (as defined by {@link ByteSource.Util#isCompatible(Object) ByteSource.Util.isCompatible}.  If the object

          * cannot be heuristically converted to a {@code ByteSource}, an {@code IllegalArgumentException} will be

          * thrown.

          *

          * @param source the byte-backed source data that will be hashed by a {@link HashService}.

          * @return this {@code Builder} instance for method chaining.

          * @throws IllegalArgumentException if the argument cannot be heuristically converted to a {@link ByteSource}

          *                                  instance.

          * @see HashRequest#getSource()

          * @see #setSource(ByteSource)

          */

         public Builder setSource(Object source) throws IllegalArgumentException {

             this.source = ByteSource.Util.bytes(source);

             return this;

         }

         /**

          * Sets a salt to be used by the {@link HashService} during hash computation.

          * <p/>

          * <b>NOTE</b>: not calling this method does not necessarily mean a salt won't be used at all - it just

          * means that the request didn't include a salt.  The servicing {@link HashService} is free to provide a salting

          * strategy for a request, even if the request did not specify one.  You can always check the result

          * {@code Hash} {@link Hash#getSalt() getSalt()} method to see what the actual

          * salt was (if any), which may or may not match this request salt.

          *

          * @param salt a salt to be used by the {@link HashService} during hash computation

          * @return this {@code Builder} instance for method chaining.

          * @see HashRequest#getSalt()

          */

         public Builder setSalt(ByteSource salt) {

             this.salt = salt;

             return this;

         }

         /**

          * Sets a salt to be used by the {@link HashService} during hash computation.

          * <p/>

          * This is a convenience alternative to {@link #setSalt(ByteSource)}: it will attempt to convert the

          * argument into a {@link ByteSource} instance using Shiro's default conversion heuristics

          * (as defined by {@link ByteSource.Util#isCompatible(Object) ByteSource.Util.isCompatible}.  If the object

          * cannot be heuristically converted to a {@code ByteSource}, an {@code IllegalArgumentException} will be

          * thrown.

          *

          * @param salt a salt to be used by the {@link HashService} during hash computation.

          * @return this {@code Builder} instance for method chaining.

          * @throws IllegalArgumentException if the argument cannot be heuristically converted to a {@link ByteSource}

          *                                  instance.

          * @see #setSalt(ByteSource)

          * @see HashRequest#getSalt()

          */

         public Builder setSalt(Object salt) throws IllegalArgumentException {

             this.salt = ByteSource.Util.bytes(salt);

             return this;

         }

         /**

          * Sets the number of requested hash iterations to be performed when computing the final {@code Hash} result.

          * Not calling this method or setting a non-positive value (0 or less) indicates that the {@code HashService}'s

          * default iteration configuration should be used.  A positive value overrides the {@code HashService}'s

          * configuration for a single request.

          * <p/>

          * Note that a {@code HashService} is free to ignore this number if it determines the number is not sufficient

          * to meet a desired level of security. You can always check the result

          * {@code Hash} {@link Hash#getIterations() getIterations()} method to see what the actual

          * number of iterations was, which may or may not match this request salt.

          *

          * @param iterations the number of requested hash iterations to be performed when computing the final

          *                   {@code Hash} result.

          * @return this {@code Builder} instance for method chaining.

          * @see HashRequest#getIterations()

          */

         public Builder setIterations(int iterations) {

             this.iterations = iterations;

             return this;

         }

         /**

          * Sets the name of the hash algorithm the {@code HashService} should use when computing the {@link Hash}.

          * Not calling this method or setting it to {@code null} indicates the the default algorithm configuration of

          * the {@code HashService} should be used.  A non-null value

          * overrides the {@code HashService}'s configuration for a single request.

          * <p/>

          * Note that a {@code HashService} is free to ignore this value if it determines that the algorithm is not

          * sufficient to meet a desired level of security. You can always check the result

          * {@code Hash} {@link Hash#getAlgorithmName() getAlgorithmName()} method to see what the actual

          * algorithm was, which may or may not match this request salt.

          *

          * @param algorithmName the name of the hash algorithm the {@code HashService} should use when computing the

          *                      {@link Hash}, or {@code null} if the default algorithm configuration of the

          *                      {@code HashService} should be used.

          * @return this {@code Builder} instance for method chaining.

          * @see HashRequest#getAlgorithmName()

          */

         public Builder setAlgorithmName(String algorithmName) {

             this.algorithmName = algorithmName;

             return this;

         }

         /**

          * Builds a {@link HashRequest} instance reflecting the specified configuration.

          *

          * @return a {@link HashRequest} instance reflecting the specified configuration.

          */

         public HashRequest build() {

             return new SimpleHashRequest(this.algorithmName, this.source, this.salt, this.iterations);

         }

     }

 }