/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* This software is subject to the Microsoft Public License (Ms-PL).
* A copy of the license can be found in the license.htm file included
* in this distribution.
*
* You must not remove this notice, or any other, from this software.
*
* ***************************************************************************/
namespace System.Web.Mvc{
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Web.Mvc.Resources;
internal sealed class ActionMethodSelector {
public ActionMethodSelector(Type controllerType) {
ControllerType = controllerType;
PopulateLookupTables();
}
public Type ControllerType {
get;
private set;
}
public MethodInfo[] AliasedMethods {
get;
private set;
}
public ILookup<string, MethodInfo> NonAliasedMethods {
get;
private set;
}
private AmbiguousMatchException CreateAmbiguousMatchException(List<MethodInfo> ambiguousMethods, string actionName) {
StringBuilder exceptionMessageBuilder = new StringBuilder();
foreach (MethodInfo methodInfo in ambiguousMethods) {
string controllerAction = Convert.ToString(methodInfo, CultureInfo.CurrentUICulture);
string controllerType = methodInfo.DeclaringType.FullName;
exceptionMessageBuilder.AppendLine();
exceptionMessageBuilder.AppendFormat(CultureInfo.CurrentUICulture, MvcResources.ActionMethodSelector_AmbiguousMatchType, controllerAction, controllerType);
}
string message = String.Format(CultureInfo.CurrentUICulture, MvcResources.ActionMethodSelector_AmbiguousMatch,
actionName, ControllerType.Name, exceptionMessageBuilder);
return new AmbiguousMatchException(message);
}
public MethodInfo FindActionMethod(ControllerContext controllerContext, string actionName) {
List<MethodInfo> methodsMatchingName = GetMatchingAliasedMethods(controllerContext, actionName);
methodsMatchingName.AddRange(NonAliasedMethods[actionName]);
List<MethodInfo> finalMethods = RunSelectionFilters(controllerContext, methodsMatchingName);
switch (finalMethods.Count) {
case 0:
return null;
case 1:
return finalMethods[0];
default:
throw CreateAmbiguousMatchException(finalMethods, actionName);
}
}
internal List<MethodInfo> GetMatchingAliasedMethods(ControllerContext controllerContext, string actionName) {
// find all aliased methods which are opting in to this request
// to opt in, all attributes defined on the method must return true
var methods = from methodInfo in AliasedMethods
let attrs = (ActionNameSelectorAttribute[])methodInfo.GetCustomAttributes(typeof(ActionNameSelectorAttribute), true /* inherit */)
where attrs.All(attr => attr.IsValidName(controllerContext, actionName, methodInfo))
select methodInfo;
return methods.ToList();
}
private static bool IsMethodDecoratedWithAliasingAttribute(MethodInfo methodInfo) {
return methodInfo.IsDefined(typeof(ActionNameSelectorAttribute), true /* inherit */);
}
private static bool IsValidActionMethod(MethodInfo methodInfo) {
return !(methodInfo.IsSpecialName ||
methodInfo.GetBaseDefinition().DeclaringType.IsAssignableFrom(typeof(Controller)));
}
private void PopulateLookupTables() {
MethodInfo[] allMethods = ControllerType.GetMethods(BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public);
MethodInfo[] actionMethods = Array.FindAll(allMethods, IsValidActionMethod);
AliasedMethods = Array.FindAll(actionMethods, IsMethodDecoratedWithAliasingAttribute);
NonAliasedMethods = actionMethods.Except(AliasedMethods).ToLookup(method => method.Name, StringComparer.OrdinalIgnoreCase);
}
private static List<MethodInfo> RunSelectionFilters(ControllerContext controllerContext, List<MethodInfo> methodInfos) {
// remove all methods which are opting out of this request
// to opt out, at least one attribute defined on the method must return false
List<MethodInfo> matchesWithSelectionAttributes = new List<MethodInfo>();
List<MethodInfo> matchesWithoutSelectionAttributes = new List<MethodInfo>();
foreach (MethodInfo methodInfo in methodInfos) {
ActionMethodSelectorAttribute[] attrs = (ActionMethodSelectorAttribute[])methodInfo.GetCustomAttributes(typeof(ActionMethodSelectorAttribute), true /* inherit */);
if (attrs.Length == 0) {
matchesWithoutSelectionAttributes.Add(methodInfo);
}
else if (attrs.All(attr => attr.IsValidForRequest(controllerContext, methodInfo))) {
matchesWithSelectionAttributes.Add(methodInfo);
}
}
// if a matching action method had a selection attribute, consider it more specific than a matching action method
// without a selection attribute
return (matchesWithSelectionAttributes.Count > 0) ? matchesWithSelectionAttributes : matchesWithoutSelectionAttributes;
}
}
}
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