Nate McMaster
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b0441192c3
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// Copyright (c) .NET Foundation. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System;
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using System.Linq;
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using System.Linq.Expressions;
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using System.Reflection;
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using System.Runtime.ExceptionServices;
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#if ActivatorUtilities_In_DependencyInjection
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using Microsoft.Extensions.Internal;
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namespace Microsoft.Extensions.DependencyInjection
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#else
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namespace Microsoft.Extensions.Internal
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#endif
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{
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/// <summary>
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/// Helper code for the various activator services.
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/// </summary>
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#if ActivatorUtilities_In_DependencyInjection
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public
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#else
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// Do not take a dependency on this class unless you are explicitly trying to avoid taking a
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// dependency on Microsoft.AspNetCore.DependencyInjection.Abstractions.
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internal
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#endif
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static class ActivatorUtilities
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{
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private static readonly MethodInfo GetServiceInfo =
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GetMethodInfo<Func<IServiceProvider, Type, Type, bool, object>>((sp, t, r, c) => GetService(sp, t, r, c));
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/// <summary>
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/// Instantiate a type with constructor arguments provided directly and/or from an <see cref="IServiceProvider"/>.
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/// </summary>
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/// <param name="provider">The service provider used to resolve dependencies</param>
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/// <param name="instanceType">The type to activate</param>
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/// <param name="parameters">Constructor arguments not provided by the <paramref name="provider"/>.</param>
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/// <returns>An activated object of type instanceType</returns>
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public static object CreateInstance(IServiceProvider provider, Type instanceType, params object[] parameters)
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{
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int bestLength = -1;
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var seenPreferred = false;
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ConstructorMatcher bestMatcher = null;
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if (!instanceType.GetTypeInfo().IsAbstract)
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{
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foreach (var constructor in instanceType
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.GetTypeInfo()
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.DeclaredConstructors
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.Where(c => !c.IsStatic && c.IsPublic))
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{
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var matcher = new ConstructorMatcher(constructor);
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var isPreferred = constructor.IsDefined(typeof(ActivatorUtilitiesConstructorAttribute), false);
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var length = matcher.Match(parameters);
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if (isPreferred)
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{
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if (seenPreferred)
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{
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ThrowMultipleCtorsMarkedWithAttributeException();
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}
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if (length == -1)
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{
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ThrowMarkedCtorDoesNotTakeAllProvidedArguments();
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}
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}
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if (isPreferred || bestLength < length)
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{
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bestLength = length;
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bestMatcher = matcher;
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}
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seenPreferred |= isPreferred;
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}
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}
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if (bestMatcher == null)
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{
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var message = $"A suitable constructor for type '{instanceType}' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.";
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throw new InvalidOperationException(message);
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}
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return bestMatcher.CreateInstance(provider);
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}
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/// <summary>
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/// Create a delegate that will instantiate a type with constructor arguments provided directly
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/// and/or from an <see cref="IServiceProvider"/>.
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/// </summary>
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/// <param name="instanceType">The type to activate</param>
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/// <param name="argumentTypes">
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/// The types of objects, in order, that will be passed to the returned function as its second parameter
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/// </param>
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/// <returns>
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/// A factory that will instantiate instanceType using an <see cref="IServiceProvider"/>
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/// and an argument array containing objects matching the types defined in argumentTypes
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/// </returns>
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public static ObjectFactory CreateFactory(Type instanceType, Type[] argumentTypes)
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{
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FindApplicableConstructor(instanceType, argumentTypes, out ConstructorInfo constructor, out int?[] parameterMap);
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var provider = Expression.Parameter(typeof(IServiceProvider), "provider");
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var argumentArray = Expression.Parameter(typeof(object[]), "argumentArray");
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var factoryExpressionBody = BuildFactoryExpression(constructor, parameterMap, provider, argumentArray);
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var factoryLamda = Expression.Lambda<Func<IServiceProvider, object[], object>>(
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factoryExpressionBody, provider, argumentArray);
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var result = factoryLamda.Compile();
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return result.Invoke;
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}
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/// <summary>
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/// Instantiate a type with constructor arguments provided directly and/or from an <see cref="IServiceProvider"/>.
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/// </summary>
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/// <typeparam name="T">The type to activate</typeparam>
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/// <param name="provider">The service provider used to resolve dependencies</param>
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/// <param name="parameters">Constructor arguments not provided by the <paramref name="provider"/>.</param>
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/// <returns>An activated object of type T</returns>
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public static T CreateInstance<T>(IServiceProvider provider, params object[] parameters)
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{
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return (T)CreateInstance(provider, typeof(T), parameters);
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}
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/// <summary>
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/// Retrieve an instance of the given type from the service provider. If one is not found then instantiate it directly.
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/// </summary>
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/// <typeparam name="T">The type of the service</typeparam>
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/// <param name="provider">The service provider used to resolve dependencies</param>
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/// <returns>The resolved service or created instance</returns>
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public static T GetServiceOrCreateInstance<T>(IServiceProvider provider)
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{
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return (T)GetServiceOrCreateInstance(provider, typeof(T));
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}
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/// <summary>
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/// Retrieve an instance of the given type from the service provider. If one is not found then instantiate it directly.
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/// </summary>
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/// <param name="provider">The service provider</param>
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/// <param name="type">The type of the service</param>
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/// <returns>The resolved service or created instance</returns>
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public static object GetServiceOrCreateInstance(IServiceProvider provider, Type type)
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{
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return provider.GetService(type) ?? CreateInstance(provider, type);
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}
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private static MethodInfo GetMethodInfo<T>(Expression<T> expr)
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{
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var mc = (MethodCallExpression)expr.Body;
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return mc.Method;
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}
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private static object GetService(IServiceProvider sp, Type type, Type requiredBy, bool isDefaultParameterRequired)
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{
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var service = sp.GetService(type);
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if (service == null && !isDefaultParameterRequired)
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{
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var message = $"Unable to resolve service for type '{type}' while attempting to activate '{requiredBy}'.";
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throw new InvalidOperationException(message);
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}
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return service;
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}
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private static Expression BuildFactoryExpression(
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ConstructorInfo constructor,
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int?[] parameterMap,
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Expression serviceProvider,
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Expression factoryArgumentArray)
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{
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var constructorParameters = constructor.GetParameters();
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var constructorArguments = new Expression[constructorParameters.Length];
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for (var i = 0; i < constructorParameters.Length; i++)
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{
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var constructorParameter = constructorParameters[i];
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var parameterType = constructorParameter.ParameterType;
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var hasDefaultValue = ParameterDefaultValue.TryGetDefaultValue(constructorParameter, out var defaultValue);
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if (parameterMap[i] != null)
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{
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constructorArguments[i] = Expression.ArrayAccess(factoryArgumentArray, Expression.Constant(parameterMap[i]));
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}
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else
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{
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var parameterTypeExpression = new Expression[] { serviceProvider,
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Expression.Constant(parameterType, typeof(Type)),
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Expression.Constant(constructor.DeclaringType, typeof(Type)),
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Expression.Constant(hasDefaultValue) };
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constructorArguments[i] = Expression.Call(GetServiceInfo, parameterTypeExpression);
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}
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// Support optional constructor arguments by passing in the default value
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// when the argument would otherwise be null.
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if (hasDefaultValue)
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{
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var defaultValueExpression = Expression.Constant(defaultValue);
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constructorArguments[i] = Expression.Coalesce(constructorArguments[i], defaultValueExpression);
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}
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constructorArguments[i] = Expression.Convert(constructorArguments[i], parameterType);
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}
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return Expression.New(constructor, constructorArguments);
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}
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private static void FindApplicableConstructor(
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Type instanceType,
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Type[] argumentTypes,
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out ConstructorInfo matchingConstructor,
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out int?[] parameterMap)
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{
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matchingConstructor = null;
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parameterMap = null;
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if (!TryFindPreferredConstructor(instanceType, argumentTypes, ref matchingConstructor, ref parameterMap) &&
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!TryFindMatchingConstructor(instanceType, argumentTypes, ref matchingConstructor, ref parameterMap))
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{
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var message = $"A suitable constructor for type '{instanceType}' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.";
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throw new InvalidOperationException(message);
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}
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}
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// Tries to find constructor based on provided argument types
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private static bool TryFindMatchingConstructor(
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Type instanceType,
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Type[] argumentTypes,
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ref ConstructorInfo matchingConstructor,
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ref int?[] parameterMap)
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{
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foreach (var constructor in instanceType.GetTypeInfo().DeclaredConstructors)
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{
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if (constructor.IsStatic || !constructor.IsPublic)
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{
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continue;
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}
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if (TryCreateParameterMap(constructor.GetParameters(), argumentTypes, out int?[] tempParameterMap))
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{
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if (matchingConstructor != null)
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{
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throw new InvalidOperationException($"Multiple constructors accepting all given argument types have been found in type '{instanceType}'. There should only be one applicable constructor.");
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}
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matchingConstructor = constructor;
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parameterMap = tempParameterMap;
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}
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}
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return matchingConstructor != null;
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}
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// Tries to find constructor marked with ActivatorUtilitiesConstructorAttribute
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private static bool TryFindPreferredConstructor(
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Type instanceType,
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Type[] argumentTypes,
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ref ConstructorInfo matchingConstructor,
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ref int?[] parameterMap)
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{
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var seenPreferred = false;
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foreach (var constructor in instanceType.GetTypeInfo().DeclaredConstructors)
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{
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if (constructor.IsStatic || !constructor.IsPublic)
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{
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continue;
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}
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if (constructor.IsDefined(typeof(ActivatorUtilitiesConstructorAttribute), false))
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{
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if (seenPreferred)
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{
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ThrowMultipleCtorsMarkedWithAttributeException();
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}
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if (!TryCreateParameterMap(constructor.GetParameters(), argumentTypes, out int?[] tempParameterMap))
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{
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ThrowMarkedCtorDoesNotTakeAllProvidedArguments();
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}
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matchingConstructor = constructor;
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parameterMap = tempParameterMap;
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seenPreferred = true;
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}
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}
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return matchingConstructor != null;
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}
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// Creates an injective parameterMap from givenParameterTypes to assignable constructorParameters.
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// Returns true if each given parameter type is assignable to a unique; otherwise, false.
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private static bool TryCreateParameterMap(ParameterInfo[] constructorParameters, Type[] argumentTypes, out int?[] parameterMap)
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{
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parameterMap = new int?[constructorParameters.Length];
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for (var i = 0; i < argumentTypes.Length; i++)
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{
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var foundMatch = false;
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var givenParameter = argumentTypes[i].GetTypeInfo();
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for (var j = 0; j < constructorParameters.Length; j++)
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{
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if (parameterMap[j] != null)
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{
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// This ctor parameter has already been matched
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continue;
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}
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if (constructorParameters[j].ParameterType.GetTypeInfo().IsAssignableFrom(givenParameter))
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{
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foundMatch = true;
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parameterMap[j] = i;
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break;
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}
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}
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if (!foundMatch)
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{
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return false;
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}
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}
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return true;
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}
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private class ConstructorMatcher
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{
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private readonly ConstructorInfo _constructor;
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private readonly ParameterInfo[] _parameters;
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private readonly object[] _parameterValues;
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private readonly bool[] _parameterValuesSet;
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public ConstructorMatcher(ConstructorInfo constructor)
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{
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_constructor = constructor;
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_parameters = _constructor.GetParameters();
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_parameterValuesSet = new bool[_parameters.Length];
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_parameterValues = new object[_parameters.Length];
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}
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public int Match(object[] givenParameters)
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{
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var applyIndexStart = 0;
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var applyExactLength = 0;
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for (var givenIndex = 0; givenIndex != givenParameters.Length; givenIndex++)
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{
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var givenType = givenParameters[givenIndex]?.GetType().GetTypeInfo();
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var givenMatched = false;
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for (var applyIndex = applyIndexStart; givenMatched == false && applyIndex != _parameters.Length; ++applyIndex)
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{
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if (_parameterValuesSet[applyIndex] == false &&
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_parameters[applyIndex].ParameterType.GetTypeInfo().IsAssignableFrom(givenType))
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{
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givenMatched = true;
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_parameterValuesSet[applyIndex] = true;
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_parameterValues[applyIndex] = givenParameters[givenIndex];
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if (applyIndexStart == applyIndex)
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{
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applyIndexStart++;
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if (applyIndex == givenIndex)
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||||||
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{
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applyExactLength = applyIndex;
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||||||
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}
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||||||
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}
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}
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}
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if (givenMatched == false)
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{
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return -1;
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}
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}
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return applyExactLength;
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||||||
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}
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||||||
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||||||
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public object CreateInstance(IServiceProvider provider)
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||||||
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{
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||||||
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for (var index = 0; index != _parameters.Length; index++)
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||||||
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{
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||||||
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if (_parameterValuesSet[index] == false)
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||||||
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{
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||||||
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var value = provider.GetService(_parameters[index].ParameterType);
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||||||
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if (value == null)
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||||||
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{
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||||||
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if (!ParameterDefaultValue.TryGetDefaultValue(_parameters[index], out var defaultValue))
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||||||
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{
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||||||
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throw new InvalidOperationException($"Unable to resolve service for type '{_parameters[index].ParameterType}' while attempting to activate '{_constructor.DeclaringType}'.");
|
||||||
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}
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||||||
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else
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||||||
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{
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||||||
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_parameterValues[index] = defaultValue;
|
||||||
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}
|
||||||
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}
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||||||
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else
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||||||
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{
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||||||
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_parameterValues[index] = value;
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||||||
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}
|
||||||
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}
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||||||
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}
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||||||
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|
||||||
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try
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||||||
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{
|
||||||
|
return _constructor.Invoke(_parameterValues);
|
||||||
|
}
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||||||
|
catch (TargetInvocationException ex)
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||||||
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{
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||||||
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ExceptionDispatchInfo.Capture(ex.InnerException).Throw();
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||||||
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// The above line will always throw, but the compiler requires we throw explicitly.
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||||||
|
throw;
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||||||
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}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private static void ThrowMultipleCtorsMarkedWithAttributeException()
|
||||||
|
{
|
||||||
|
throw new InvalidOperationException($"Multiple constructors were marked with {nameof(ActivatorUtilitiesConstructorAttribute)}.");
|
||||||
|
}
|
||||||
|
|
||||||
|
private static void ThrowMarkedCtorDoesNotTakeAllProvidedArguments()
|
||||||
|
{
|
||||||
|
throw new InvalidOperationException($"Constructor marked with {nameof(ActivatorUtilitiesConstructorAttribute)} does not accept all given argument types.");
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
@ -0,0 +1,26 @@
|
||||||
|
// Copyright (c) .NET Foundation. All rights reserved.
|
||||||
|
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
|
||||||
|
|
||||||
|
using System;
|
||||||
|
|
||||||
|
#if ActivatorUtilities_In_DependencyInjection
|
||||||
|
namespace Microsoft.Extensions.DependencyInjection
|
||||||
|
#else
|
||||||
|
namespace Microsoft.Extensions.Internal
|
||||||
|
#endif
|
||||||
|
{
|
||||||
|
/// <summary>
|
||||||
|
/// Marks the constructor to be used when activating type using <see cref="ActivatorUtilities"/>.
|
||||||
|
/// </summary>
|
||||||
|
|
||||||
|
#if ActivatorUtilities_In_DependencyInjection
|
||||||
|
public
|
||||||
|
#else
|
||||||
|
// Do not take a dependency on this class unless you are explicitly trying to avoid taking a
|
||||||
|
// dependency on Microsoft.AspNetCore.DependencyInjection.Abstractions.
|
||||||
|
internal
|
||||||
|
#endif
|
||||||
|
class ActivatorUtilitiesConstructorAttribute: Attribute
|
||||||
|
{
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
@ -0,0 +1,25 @@
|
||||||
|
// Copyright (c) .NET Foundation. All rights reserved.
|
||||||
|
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
|
||||||
|
|
||||||
|
using System;
|
||||||
|
|
||||||
|
#if ActivatorUtilities_In_DependencyInjection
|
||||||
|
namespace Microsoft.Extensions.DependencyInjection
|
||||||
|
#else
|
||||||
|
namespace Microsoft.Extensions.Internal
|
||||||
|
#endif
|
||||||
|
{
|
||||||
|
|
||||||
|
/// <summary>
|
||||||
|
/// The result of <see cref="ActivatorUtilities.CreateFactory(Type, Type[])"/>.
|
||||||
|
/// </summary>
|
||||||
|
/// <param name="serviceProvider">The <see cref="IServiceProvider"/> to get service arguments from.</param>
|
||||||
|
/// <param name="arguments">Additional constructor arguments.</param>
|
||||||
|
/// <returns>The instantiated type.</returns>
|
||||||
|
#if ActivatorUtilities_In_DependencyInjection
|
||||||
|
public
|
||||||
|
#else
|
||||||
|
internal
|
||||||
|
#endif
|
||||||
|
delegate object ObjectFactory(IServiceProvider serviceProvider, object[] arguments);
|
||||||
|
}
|
||||||
|
|
@ -0,0 +1,8 @@
|
||||||
|
<Project>
|
||||||
|
<ItemGroup>
|
||||||
|
<Compile Include="$(MSBuildThisFileDirectory)..\ParameterDefaultValue\ParameterDefaultValue.cs">
|
||||||
|
<Pack>true</Pack>
|
||||||
|
<PackagePath>$(ContentTargetFolders)\cs\netstandard1.0\</PackagePath>
|
||||||
|
</Compile>
|
||||||
|
</ItemGroup>
|
||||||
|
</Project>
|
||||||
|
|
@ -0,0 +1,47 @@
|
||||||
|
// Copyright (c) .NET Foundation. All rights reserved.
|
||||||
|
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
|
||||||
|
|
||||||
|
using System;
|
||||||
|
using System.Reflection;
|
||||||
|
|
||||||
|
namespace Microsoft.Extensions.Internal
|
||||||
|
{
|
||||||
|
internal class ParameterDefaultValue
|
||||||
|
{
|
||||||
|
public static bool TryGetDefaultValue(ParameterInfo parameter, out object defaultValue)
|
||||||
|
{
|
||||||
|
bool hasDefaultValue;
|
||||||
|
var tryToGetDefaultValue = true;
|
||||||
|
defaultValue = null;
|
||||||
|
|
||||||
|
try
|
||||||
|
{
|
||||||
|
hasDefaultValue = parameter.HasDefaultValue;
|
||||||
|
}
|
||||||
|
catch (FormatException) when (parameter.ParameterType == typeof(DateTime))
|
||||||
|
{
|
||||||
|
// Workaround for https://github.com/dotnet/corefx/issues/12338
|
||||||
|
// If HasDefaultValue throws FormatException for DateTime
|
||||||
|
// we expect it to have default value
|
||||||
|
hasDefaultValue = true;
|
||||||
|
tryToGetDefaultValue = false;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (hasDefaultValue)
|
||||||
|
{
|
||||||
|
if (tryToGetDefaultValue)
|
||||||
|
{
|
||||||
|
defaultValue = parameter.DefaultValue;
|
||||||
|
}
|
||||||
|
|
||||||
|
// Workaround for https://github.com/dotnet/corefx/issues/11797
|
||||||
|
if (defaultValue == null && parameter.ParameterType.IsValueType)
|
||||||
|
{
|
||||||
|
defaultValue = Activator.CreateInstance(parameter.ParameterType);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
return hasDefaultValue;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
Loading…
Reference in New Issue