Trigger4Win/libcmdline/Attributes/HelpVerbOptionAttribute.cs
2015-04-10 00:09:58 +00:00

113 lines
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4.6 KiB
C#

#region License
// <copyright file="HelpVerbOptionAttribute.cs" company="Giacomo Stelluti Scala">
// Copyright 2015-2013 Giacomo Stelluti Scala
// </copyright>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#endregion
#region Using Directives
using System;
using System.Reflection;
using CommandLine.Extensions;
using CommandLine.Infrastructure;
#endregion
namespace CommandLine
{
/// <summary>
/// Indicates the instance method that must be invoked when it becomes necessary show your help screen.
/// The method signature is an instance method with that accepts and returns a <see cref="System.String"/>.
/// </summary>
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public sealed class HelpVerbOptionAttribute : BaseOptionAttribute
{
private const string DefaultHelpText = "Display more information on a specific command.";
/// <summary>
/// Initializes a new instance of the <see cref="CommandLine.HelpVerbOptionAttribute"/> class.
/// Although it is possible, it is strongly discouraged redefine the long name for this option
/// not to disorient your users.
/// </summary>
public HelpVerbOptionAttribute()
: this("help")
{
HelpText = DefaultHelpText;
}
/// <summary>
/// Initializes a new instance of the <see cref="CommandLine.HelpVerbOptionAttribute"/> class
/// with the specified long name. Use parameter less constructor instead.
/// </summary>
/// <param name="longName">Help verb option alternative name.</param>
/// <remarks>
/// It's highly not recommended change the way users invoke help. It may create confusion.
/// </remarks>
public HelpVerbOptionAttribute(string longName)
: base(null, longName)
{
HelpText = DefaultHelpText;
}
/// <summary>
/// Help verb command do not support short name by design.
/// </summary>
public override char? ShortName
{
get { return null; }
internal set { throw new InvalidOperationException(SR.InvalidOperationException_DoNotUseShortNameForVerbCommands); }
}
/// <summary>
/// Help verb command like ordinary help option cannot be mandatory by design.
/// </summary>
public override bool Required
{
get { return false; }
set { throw new InvalidOperationException(SR.InvalidOperationException_DoNotSetRequiredPropertyForVerbCommands); }
}
internal static void InvokeMethod(
object target,
Pair<MethodInfo, HelpVerbOptionAttribute> helpInfo,
string verb,
out string text)
{
text = null;
var method = helpInfo.Left;
if (!CheckMethodSignature(method))
{
throw new MemberAccessException(
SR.MemberAccessException_BadSignatureForHelpVerbOptionAttribute.FormatInvariant(method.Name));
}
text = (string)method.Invoke(target, new object[] { verb });
}
private static bool CheckMethodSignature(MethodInfo value)
{
if (value.ReturnType == typeof(string) && value.GetParameters().Length == 1)
{
return value.GetParameters()[0].ParameterType == typeof(string);
}
return false;
}
}
}