/IronPython_Main/Runtime/Microsoft.Scripting/Utils/ContractUtils.cs

/* ****************************************************************************

 *

 * Copyright (c) Microsoft Corporation. 

 *

 * This source code is subject to terms and conditions of the Apache License, Version 2.0. A 

 * copy of the license can be found in the License.html file at the root of this distribution. If 

 * you cannot locate the  Apache License, Version 2.0, please send an email to 

 * dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound 

 * by the terms of the Apache License, Version 2.0.

 *

 * You must not remove this notice, or any other, from this software.

 *

 *

 * ***************************************************************************/



#if !CLR2

using System.Linq.Expressions;

#else

using Microsoft.Scripting.Ast;

#endif



using System;

using System.Collections;

using System.Collections.Generic;

using System.Diagnostics;



namespace Microsoft.Scripting.Utils {

    internal static class ContractUtils {

        public static void RequiresNotNull(object value, string paramName) {

            Assert.NotEmpty(paramName);



            if (value == null) {

                throw new ArgumentNullException(paramName);

            }

        }



        public static void Requires(bool precondition) {

            if (!precondition) {

                throw new ArgumentException(Strings.MethodPreconditionViolated);

            }

        }



        public static void Requires(bool precondition, string paramName) {

            Assert.NotEmpty(paramName);



            if (!precondition) {

                throw new ArgumentException(Strings.InvalidArgumentValue, paramName);

            }

        }



        public static void Requires(bool precondition, string paramName, string message) {

            Assert.NotEmpty(paramName);



            if (!precondition) {

                throw new ArgumentException(message, paramName);

            }

        }



        public static void RequiresNotEmpty(string str, string paramName) {

            RequiresNotNull(str, paramName);

            if (str.Length == 0) {

                throw new ArgumentException(Strings.NonEmptyStringRequired, paramName);

            }

        }



        public static void RequiresNotEmpty<T>(ICollection<T> collection, string paramName) {

            RequiresNotNull(collection, paramName);

            if (collection.Count == 0) {

                throw new ArgumentException(Strings.NonEmptyCollectionRequired, paramName);

            }

        }



        /// <summary>

        /// Requires the range [offset, offset + count] to be a subset of [0, array.Count].

        /// </summary>

        /// <exception cref="ArgumentOutOfRangeException">Offset or count are out of range.</exception>

        public static void RequiresArrayRange<T>(IList<T> array, int offset, int count, string offsetName, string countName) {

            Assert.NotNull(array);

            RequiresArrayRange(array.Count, offset, count, offsetName, countName);

        }



        /// <summary>

        /// Requires the range [offset, offset + count] to be a subset of [0, array.Count].

        /// </summary>

        /// <exception cref="ArgumentOutOfRangeException">Offset or count are out of range.</exception>

        public static void RequiresArrayRange(int arraySize, int offset, int count, string offsetName, string countName) {

            Assert.NotEmpty(offsetName);

            Assert.NotEmpty(countName);

            Debug.Assert(arraySize >= 0);



            if (count < 0) throw new ArgumentOutOfRangeException(countName);

            if (offset < 0 || arraySize - offset < count) throw new ArgumentOutOfRangeException(offsetName);

        }



        /// <summary>

        /// Requires the array and all its items to be non-null.

        /// </summary>

        public static void RequiresNotNullItems<T>(IList<T> array, string arrayName) {

            Assert.NotNull(arrayName);

            RequiresNotNull(array, arrayName);



            for (int i = 0; i < array.Count; i++) {

                if (array[i] == null) {

                    throw ExceptionUtils.MakeArgumentItemNullException(i, arrayName);

                }

            }

        }



        /// <summary>

        /// Requires the enumerable collection and all its items to be non-null.

        /// </summary>

        public static void RequiresNotNullItems<T>(IEnumerable<T> collection, string collectionName) {

            Assert.NotNull(collectionName);

            RequiresNotNull(collection, collectionName);



            int i = 0;

            foreach (var item in collection) {

                if (item == null) {

                    throw ExceptionUtils.MakeArgumentItemNullException(i, collectionName);

                }

                i++;

            }

        }



        /// <summary>

        /// Requires the range [offset, offset + count] to be a subset of [0, array.Count].

        /// </summary>

        /// <exception cref="ArgumentNullException">Array is <c>null</c>.</exception>

        /// <exception cref="ArgumentOutOfRangeException">Offset or count are out of range.</exception>

        public static void RequiresListRange(IList array, int offset, int count, string offsetName, string countName) {

            Assert.NotEmpty(offsetName);

            Assert.NotEmpty(countName);

            Assert.NotNull(array);



            if (count < 0) throw new ArgumentOutOfRangeException(countName);

            if (offset < 0 || array.Count - offset < count) throw new ArgumentOutOfRangeException(offsetName);

        }

    }

}