/* ****************************************************************************
 *
 * Copyright (c) Microsoft Corporation. 
 *
 * This source code is subject to terms and conditions of the Microsoft Public License. A 
 * copy of the license can be found in the License.html file at the root of this distribution. If 
 * you cannot locate the  Microsoft Public License, 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 Microsoft Public License.
 *
 * You must not remove this notice, or any other, from this software.
 *
 *
 * ***************************************************************************/

using System.Security;
using System;

namespace Microsoft.Scripting {

    /// <summary>
    /// This class holds onto internal debugging options used in this assembly. 
    /// These options can be set via environment variables DLR_{option-name}.
    /// Boolean options map "true" to true and other values to false.
    /// 
    /// These options are for internal debugging only, and should not be
    /// exposed through any public APIs.
    /// </summary>
    internal static class DebugOptions {

        private static bool ReadOption(string name) {
#if SILVERLIGHT
            return false;
#else
            string envVar = ReadString(name);
            return envVar != null && envVar.ToLowerInvariant() == "true";
#endif
        }

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA1801:ReviewUnusedParameters", MessageId = "name")]
        private static bool ReadDebugOption(string name) {
#if DEBUG
            return ReadOption(name);
#else
            return false;
#endif
        }

        private static string ReadString(string name) {
#if SILVERLIGHT
            return null;
#else
            try {
                return Environment.GetEnvironmentVariable("DLR_" + name);
            } catch (SecurityException) {
                return null;
            }
#endif
        }

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA1801:ReviewUnusedParameters", MessageId = "name")]
        private static string ReadDebugString(string name) {
#if DEBUG
            return ReadString(name);
#else
            return null;
#endif
        }

        private readonly static bool _trackPerformance = ReadDebugOption("TrackPerformance");

        internal static bool TrackPerformance {
            get { return _trackPerformance; }
        }
    }
}