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/* ****************************************************************************
*
* 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.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Web.Mvc.Resources;
public abstract class ActionDescriptor : ICustomAttributeProvider {
private readonly static AllowMultipleAttributesCache _allowMultiplAttributesCache = new AllowMultipleAttributesCache();
private readonly static ActionMethodDispatcherCache _staticDispatcherCache = new ActionMethodDispatcherCache();
private ActionMethodDispatcherCache _instanceDispatcherCache;
private static readonly ActionSelector[] _emptySelectors = new ActionSelector[0];
public abstract string ActionName {
get;
}
public abstract ControllerDescriptor ControllerDescriptor {
get;
}
internal ActionMethodDispatcherCache DispatcherCache {
get {
if (_instanceDispatcherCache == null) {
_instanceDispatcherCache = _staticDispatcherCache;
}
return _instanceDispatcherCache;
}
set {
_instanceDispatcherCache = value;
}
}
public abstract object Execute(ControllerContext controllerContext, IDictionary<string, object> parameters);
internal static object ExtractParameterFromDictionary(ParameterInfo parameterInfo, IDictionary<string, object> parameters, MethodInfo methodInfo) {
object value;
if (!parameters.TryGetValue(parameterInfo.Name, out value)) {
// the key should always be present, even if the parameter value is null
string message = String.Format(CultureInfo.CurrentUICulture, MvcResources.ReflectedActionDescriptor_ParameterNotInDictionary,
parameterInfo.Name, parameterInfo.ParameterType, methodInfo, methodInfo.DeclaringType);
throw new ArgumentException(message, "parameters");
}
if (value == null && !TypeHelpers.TypeAllowsNullValue(parameterInfo.ParameterType)) {
// tried to pass a null value for a non-nullable parameter type
string message = String.Format(CultureInfo.CurrentUICulture, MvcResources.ReflectedActionDescriptor_ParameterCannotBeNull,
parameterInfo.Name, parameterInfo.ParameterType, methodInfo, methodInfo.DeclaringType);
throw new ArgumentException(message, "parameters");
}
if (value != null && !parameterInfo.ParameterType.IsInstanceOfType(value)) {
// value was supplied but is not of the proper type
string message = String.Format(CultureInfo.CurrentUICulture, MvcResources.ReflectedActionDescriptor_ParameterValueHasWrongType,
parameterInfo.Name, methodInfo, methodInfo.DeclaringType, value.GetType(), parameterInfo.ParameterType);
throw new ArgumentException(message, "parameters");
}
return value;
}
internal static object ExtractParameterOrDefaultFromDictionary(ParameterInfo parameterInfo, IDictionary<string, object> parameters) {
Type parameterType = parameterInfo.ParameterType;
object value;
parameters.TryGetValue(parameterInfo.Name, out value);
// if wrong type, replace with default instance
if (parameterType.IsInstanceOfType(value)) {
return value;
}
else {
object defaultValue;
if (ParameterInfoUtil.TryGetDefaultValue(parameterInfo, out defaultValue)) {
return defaultValue;
}
else {
return TypeHelpers.GetDefaultValue(parameterType);
}
}
}
public virtual object[] GetCustomAttributes(bool inherit) {
return GetCustomAttributes(typeof(object), inherit);
}
public virtual object[] GetCustomAttributes(Type attributeType, bool inherit) {
if (attributeType == null) {
throw new ArgumentNullException("attributeType");
}
return (object[])Array.CreateInstance(attributeType, 0);
}
[SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate",
Justification = "This method may perform non-trivial work.")]
public virtual FilterInfo GetFilters() {
return new FilterInfo();
}
internal static FilterInfo GetFilters(MethodInfo methodInfo) {
// Enumerable.OrderBy() is a stable sort, so this method preserves scope ordering.
FilterAttribute[] typeFilters = (FilterAttribute[])methodInfo.ReflectedType.GetCustomAttributes(typeof(FilterAttribute), true /* inherit */);
FilterAttribute[] methodFilters = (FilterAttribute[])methodInfo.GetCustomAttributes(typeof(FilterAttribute), true /* inherit */);
List<FilterAttribute> orderedFilters = RemoveOverriddenFilters(typeFilters.Concat(methodFilters)).OrderBy(attr => attr.Order).ToList();
FilterInfo filterInfo = new FilterInfo();
MergeFiltersIntoList(orderedFilters, filterInfo.ActionFilters);
MergeFiltersIntoList(orderedFilters, filterInfo.AuthorizationFilters);
MergeFiltersIntoList(orderedFilters, filterInfo.ExceptionFilters);
MergeFiltersIntoList(orderedFilters, filterInfo.ResultFilters);
return filterInfo;
}
public abstract ParameterDescriptor[] GetParameters();
[SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate",
Justification = "This method may perform non-trivial work.")]
public virtual ICollection<ActionSelector> GetSelectors() {
return _emptySelectors;
}
public virtual bool IsDefined(Type attributeType, bool inherit) {
if (attributeType == null) {
throw new ArgumentNullException("attributeType");
}
return false;
}
internal static void MergeFiltersIntoList<TFilter>(IList<FilterAttribute> allFilters, IList<TFilter> destFilters) where TFilter : class {
foreach (FilterAttribute filter in allFilters) {
TFilter castFilter = filter as TFilter;
if (castFilter != null) {
destFilters.Add(castFilter);
}
}
}
internal static IEnumerable<FilterAttribute> RemoveOverriddenFilters(IEnumerable<FilterAttribute> filters) {
// If an attribute is declared on both the controller and on an action method and that attribute's
// type has AllowMultiple = false (which is the default for attributes), we should ignore the attributes
// declared on the controller. The CLR's reflection implementation follows a similar algorithm when it
// encounters an overridden virtual method where both the base and the override contain some
// AllowMultiple = false attribute.
// Key = attribute type
// Value = -1 if AllowMultiple true, last index of this attribute type if AllowMultiple false
Dictionary<Type, int> attrsIndexes = new Dictionary<Type, int>();
FilterAttribute[] filtersList = filters.ToArray();
for (int i = 0; i < filtersList.Length; i++) {
FilterAttribute filter = filtersList[i];
Type filterType = filter.GetType();
int lastIndex;
if (attrsIndexes.TryGetValue(filterType, out lastIndex)) {
if (lastIndex >= 0) {
// this filter already exists and AllowMultiple = false, so clear last entry
filtersList[lastIndex] = null;
attrsIndexes[filterType] = i;
}
}
else {
// not found - add to dictionary
// exactly one AttributeUsageAttribute will always be present
bool allowMultiple = _allowMultiplAttributesCache.IsMultiUseAttribute(filterType);
attrsIndexes[filterType] = (allowMultiple) ? -1 : i;
}
}
// any duplicated attributes have now been nulled out, so just return remaining attributes
return filtersList.Where(attr => attr != null);
}
internal static string VerifyActionMethodIsCallable(MethodInfo methodInfo) {
// we can't call instance methods where the 'this' parameter is a type other than ControllerBase
if (!methodInfo.IsStatic && !typeof(ControllerBase).IsAssignableFrom(methodInfo.ReflectedType)) {
return String.Format(CultureInfo.CurrentUICulture, MvcResources.ReflectedActionDescriptor_CannotCallInstanceMethodOnNonControllerType,
methodInfo, methodInfo.ReflectedType.FullName);
}
// we can't call methods with open generic type parameters
if (methodInfo.ContainsGenericParameters) {
return String.Format(CultureInfo.CurrentUICulture, MvcResources.ReflectedActionDescriptor_CannotCallOpenGenericMethods,
methodInfo, methodInfo.ReflectedType.FullName);
}
// we can't call methods with ref/out parameters
ParameterInfo[] parameterInfos = methodInfo.GetParameters();
foreach (ParameterInfo parameterInfo in parameterInfos) {
if (parameterInfo.IsOut || parameterInfo.ParameterType.IsByRef) {
return String.Format(CultureInfo.CurrentUICulture, MvcResources.ReflectedActionDescriptor_CannotCallMethodsWithOutOrRefParameters,
methodInfo, methodInfo.ReflectedType.FullName, parameterInfo);
}
}
// we can call this method
return null;
}
private sealed class AllowMultipleAttributesCache : ReaderWriterCache<Type, bool> {
public bool IsMultiUseAttribute(Type attributeType) {
return FetchOrCreateItem(attributeType, () => AttributeUsageAllowsMultiple(attributeType));
}
private static bool AttributeUsageAllowsMultiple(Type type) {
return (((AttributeUsageAttribute[])type.GetCustomAttributes(typeof(AttributeUsageAttribute), true))[0]).AllowMultiple;
}
}
}
}
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