// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Text;

namespace Microsoft.Extensions.ObjectPool
{
    /// <summary>
    /// A policy for pooling <see cref="StringBuilder"/> instances.
    /// </summary>
    public class StringBuilderPooledObjectPolicy : PooledObjectPolicy<StringBuilder>
    {
        /// <summary>
        /// Gets or sets the initial capacity of pooled <see cref="StringBuilder"/> instances.
        /// </summary>
        /// <value>Defaults to <c>100</c>.</value>
        public int InitialCapacity { get; set; } = 100;

        /// <summary>
        /// Gets or sets the maximum value for <see cref="StringBuilder.Capacity"/> that is allowed to be
        /// retained, when <see cref="Return(StringBuilder)"/> is invoked.
        /// </summary>
        /// <value>Defaults to <c>4096</c>.</value>
        public int MaximumRetainedCapacity { get; set; } = 4 * 1024;

        /// <inheritdoc />
        public override StringBuilder Create()
        {
            return new StringBuilder(InitialCapacity);
        }

        /// <inheritdoc />
        public override bool Return(StringBuilder obj)
        {
            if (obj.Capacity > MaximumRetainedCapacity)
            {
                // Too big. Discard this one.
                return false;
            }

            obj.Clear();
            return true;
        }
    }
}
