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add ObjectMethodExecutor

master
yangxiaodong 7 лет назад
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af9d22edaf
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ab0ccc920a
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  1. +127
    -0
      src/DotNetCore.CAP/Internal/ObjectMethodExecutor/AwaitableInfo.cs
  2. +55
    -0
      src/DotNetCore.CAP/Internal/ObjectMethodExecutor/CoercedAwaitableInfo.cs
  3. +340
    -0
      src/DotNetCore.CAP/Internal/ObjectMethodExecutor/ObjectMethodExecutor.cs
  4. +114
    -0
      src/DotNetCore.CAP/Internal/ObjectMethodExecutor/ObjectMethodExecutorAwaitable.cs
  5. +151
    -0
      src/DotNetCore.CAP/Internal/ObjectMethodExecutor/ObjectMethodExecutorFSharpSupport.cs

+ 127
- 0
src/DotNetCore.CAP/Internal/ObjectMethodExecutor/AwaitableInfo.cs Просмотреть файл

@@ -0,0 +1,127 @@
// 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.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace Microsoft.Extensions.Internal
{
internal struct AwaitableInfo
{
public Type AwaiterType { get; }
public PropertyInfo AwaiterIsCompletedProperty { get; }
public MethodInfo AwaiterGetResultMethod { get; }
public MethodInfo AwaiterOnCompletedMethod { get; }
public MethodInfo AwaiterUnsafeOnCompletedMethod { get; }
public Type ResultType { get; }
public MethodInfo GetAwaiterMethod { get; }

public AwaitableInfo(
Type awaiterType,
PropertyInfo awaiterIsCompletedProperty,
MethodInfo awaiterGetResultMethod,
MethodInfo awaiterOnCompletedMethod,
MethodInfo awaiterUnsafeOnCompletedMethod,
Type resultType,
MethodInfo getAwaiterMethod)
{
AwaiterType = awaiterType;
AwaiterIsCompletedProperty = awaiterIsCompletedProperty;
AwaiterGetResultMethod = awaiterGetResultMethod;
AwaiterOnCompletedMethod = awaiterOnCompletedMethod;
AwaiterUnsafeOnCompletedMethod = awaiterUnsafeOnCompletedMethod;
ResultType = resultType;
GetAwaiterMethod = getAwaiterMethod;
}

public static bool IsTypeAwaitable(Type type, out AwaitableInfo awaitableInfo)
{
// Based on Roslyn code: http://source.roslyn.io/#Microsoft.CodeAnalysis.Workspaces/Shared/Extensions/ISymbolExtensions.cs,db4d48ba694b9347

// Awaitable must have method matching "object GetAwaiter()"
var getAwaiterMethod = type.GetRuntimeMethods().FirstOrDefault(m =>
m.Name.Equals("GetAwaiter", StringComparison.OrdinalIgnoreCase)
&& m.GetParameters().Length == 0
&& m.ReturnType != null);
if (getAwaiterMethod == null)
{
awaitableInfo = default(AwaitableInfo);
return false;
}

var awaiterType = getAwaiterMethod.ReturnType;

// Awaiter must have property matching "bool IsCompleted { get; }"
var isCompletedProperty = awaiterType.GetRuntimeProperties().FirstOrDefault(p =>
p.Name.Equals("IsCompleted", StringComparison.OrdinalIgnoreCase)
&& p.PropertyType == typeof(bool)
&& p.GetMethod != null);
if (isCompletedProperty == null)
{
awaitableInfo = default(AwaitableInfo);
return false;
}

// Awaiter must implement INotifyCompletion
var awaiterInterfaces = awaiterType.GetInterfaces();
var implementsINotifyCompletion = awaiterInterfaces.Any(t => t == typeof(INotifyCompletion));
if (!implementsINotifyCompletion)
{
awaitableInfo = default(AwaitableInfo);
return false;
}

// INotifyCompletion supplies a method matching "void OnCompleted(Action action)"
var iNotifyCompletionMap = awaiterType
.GetTypeInfo()
.GetRuntimeInterfaceMap(typeof(INotifyCompletion));
var onCompletedMethod = iNotifyCompletionMap.InterfaceMethods.Single(m =>
m.Name.Equals("OnCompleted", StringComparison.OrdinalIgnoreCase)
&& m.ReturnType == typeof(void)
&& m.GetParameters().Length == 1
&& m.GetParameters()[0].ParameterType == typeof(Action));

// Awaiter optionally implements ICriticalNotifyCompletion
var implementsICriticalNotifyCompletion = awaiterInterfaces.Any(t => t == typeof(ICriticalNotifyCompletion));
MethodInfo unsafeOnCompletedMethod;
if (implementsICriticalNotifyCompletion)
{
// ICriticalNotifyCompletion supplies a method matching "void UnsafeOnCompleted(Action action)"
var iCriticalNotifyCompletionMap = awaiterType
.GetTypeInfo()
.GetRuntimeInterfaceMap(typeof(ICriticalNotifyCompletion));
unsafeOnCompletedMethod = iCriticalNotifyCompletionMap.InterfaceMethods.Single(m =>
m.Name.Equals("UnsafeOnCompleted", StringComparison.OrdinalIgnoreCase)
&& m.ReturnType == typeof(void)
&& m.GetParameters().Length == 1
&& m.GetParameters()[0].ParameterType == typeof(Action));
}
else
{
unsafeOnCompletedMethod = null;
}

// Awaiter must have method matching "void GetResult" or "T GetResult()"
var getResultMethod = awaiterType.GetRuntimeMethods().FirstOrDefault(m =>
m.Name.Equals("GetResult")
&& m.GetParameters().Length == 0);
if (getResultMethod == null)
{
awaitableInfo = default(AwaitableInfo);
return false;
}

awaitableInfo = new AwaitableInfo(
awaiterType,
isCompletedProperty,
getResultMethod,
onCompletedMethod,
unsafeOnCompletedMethod,
getResultMethod.ReturnType,
getAwaiterMethod);
return true;
}
}
}

+ 55
- 0
src/DotNetCore.CAP/Internal/ObjectMethodExecutor/CoercedAwaitableInfo.cs Просмотреть файл

@@ -0,0 +1,55 @@
// 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.Linq.Expressions;

namespace Microsoft.Extensions.Internal
{
internal struct CoercedAwaitableInfo
{
public AwaitableInfo AwaitableInfo { get; }
public Expression CoercerExpression { get; }
public Type CoercerResultType { get; }
public bool RequiresCoercion => CoercerExpression != null;

public CoercedAwaitableInfo(AwaitableInfo awaitableInfo)
{
AwaitableInfo = awaitableInfo;
CoercerExpression = null;
CoercerResultType = null;
}

public CoercedAwaitableInfo(Expression coercerExpression, Type coercerResultType, AwaitableInfo coercedAwaitableInfo)
{
CoercerExpression = coercerExpression;
CoercerResultType = coercerResultType;
AwaitableInfo = coercedAwaitableInfo;
}

public static bool IsTypeAwaitable(Type type, out CoercedAwaitableInfo info)
{
if (AwaitableInfo.IsTypeAwaitable(type, out var directlyAwaitableInfo))
{
info = new CoercedAwaitableInfo(directlyAwaitableInfo);
return true;
}

// It's not directly awaitable, but maybe we can coerce it.
// Currently we support coercing FSharpAsync<T>.
if (ObjectMethodExecutorFSharpSupport.TryBuildCoercerFromFSharpAsyncToAwaitable(type,
out var coercerExpression,
out var coercerResultType))
{
if (AwaitableInfo.IsTypeAwaitable(coercerResultType, out var coercedAwaitableInfo))
{
info = new CoercedAwaitableInfo(coercerExpression, coercerResultType, coercedAwaitableInfo);
return true;
}
}

info = default(CoercedAwaitableInfo);
return false;
}
}
}

+ 340
- 0
src/DotNetCore.CAP/Internal/ObjectMethodExecutor/ObjectMethodExecutor.cs Просмотреть файл

@@ -0,0 +1,340 @@
// 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.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace Microsoft.Extensions.Internal
{
internal class ObjectMethodExecutor
{
private readonly object[] _parameterDefaultValues;
private readonly MethodExecutorAsync _executorAsync;
private readonly MethodExecutor _executor;

private static readonly ConstructorInfo _objectMethodExecutorAwaitableConstructor =
typeof(ObjectMethodExecutorAwaitable).GetConstructor(new[] {
typeof(object), // customAwaitable
typeof(Func<object, object>), // getAwaiterMethod
typeof(Func<object, bool>), // isCompletedMethod
typeof(Func<object, object>), // getResultMethod
typeof(Action<object, Action>), // onCompletedMethod
typeof(Action<object, Action>) // unsafeOnCompletedMethod
});

private ObjectMethodExecutor(MethodInfo methodInfo, TypeInfo targetTypeInfo, object[] parameterDefaultValues)
{
if (methodInfo == null)
{
throw new ArgumentNullException(nameof(methodInfo));
}

MethodInfo = methodInfo;
MethodParameters = methodInfo.GetParameters();
TargetTypeInfo = targetTypeInfo;
MethodReturnType = methodInfo.ReturnType;

var isAwaitable = CoercedAwaitableInfo.IsTypeAwaitable(MethodReturnType, out var coercedAwaitableInfo);

IsMethodAsync = isAwaitable;
AsyncResultType = isAwaitable ? coercedAwaitableInfo.AwaitableInfo.ResultType : null;

// Upstream code may prefer to use the sync-executor even for async methods, because if it knows
// that the result is a specific Task<T> where T is known, then it can directly cast to that type
// and await it without the extra heap allocations involved in the _executorAsync code path.
_executor = GetExecutor(methodInfo, targetTypeInfo);

if (IsMethodAsync)
{
_executorAsync = GetExecutorAsync(methodInfo, targetTypeInfo, coercedAwaitableInfo);
}

_parameterDefaultValues = parameterDefaultValues;
}

private delegate ObjectMethodExecutorAwaitable MethodExecutorAsync(object target, params object[] parameters);

private delegate object MethodExecutor(object target, params object[] parameters);

private delegate void VoidMethodExecutor(object target, object[] parameters);

public MethodInfo MethodInfo { get; }

public ParameterInfo[] MethodParameters { get; }

public TypeInfo TargetTypeInfo { get; }

public Type AsyncResultType { get; }

// This field is made internal set because it is set in unit tests.
public Type MethodReturnType { get; internal set; }

public bool IsMethodAsync { get; }

public static ObjectMethodExecutor Create(MethodInfo methodInfo, TypeInfo targetTypeInfo)
{
return new ObjectMethodExecutor(methodInfo, targetTypeInfo, null);
}

public static ObjectMethodExecutor Create(MethodInfo methodInfo, TypeInfo targetTypeInfo, object[] parameterDefaultValues)
{
if (parameterDefaultValues == null)
{
throw new ArgumentNullException(nameof(parameterDefaultValues));
}

return new ObjectMethodExecutor(methodInfo, targetTypeInfo, parameterDefaultValues);
}

/// <summary>
/// Executes the configured method on <paramref name="target"/>. This can be used whether or not
/// the configured method is asynchronous.
/// </summary>
/// <remarks>
/// Even if the target method is asynchronous, it's desirable to invoke it using Execute rather than
/// ExecuteAsync if you know at compile time what the return type is, because then you can directly
/// "await" that value (via a cast), and then the generated code will be able to reference the
/// resulting awaitable as a value-typed variable. If you use ExecuteAsync instead, the generated
/// code will have to treat the resulting awaitable as a boxed object, because it doesn't know at
/// compile time what type it would be.
/// </remarks>
/// <param name="target">The object whose method is to be executed.</param>
/// <param name="parameters">Parameters to pass to the method.</param>
/// <returns>The method return value.</returns>
public object Execute(object target, params object[] parameters)
{
return _executor(target, parameters);
}

/// <summary>
/// Executes the configured method on <paramref name="target"/>. This can only be used if the configured
/// method is asynchronous.
/// </summary>
/// <remarks>
/// If you don't know at compile time the type of the method's returned awaitable, you can use ExecuteAsync,
/// which supplies an awaitable-of-object. This always works, but can incur several extra heap allocations
/// as compared with using Execute and then using "await" on the result value typecasted to the known
/// awaitable type. The possible extra heap allocations are for:
///
/// 1. The custom awaitable (though usually there's a heap allocation for this anyway, since normally
/// it's a reference type, and you normally create a new instance per call).
/// 2. The custom awaiter (whether or not it's a value type, since if it's not, you need a new instance
/// of it, and if it is, it will have to be boxed so the calling code can reference it as an object).
/// 3. The async result value, if it's a value type (it has to be boxed as an object, since the calling
/// code doesn't know what type it's going to be).
/// </remarks>
/// <param name="target">The object whose method is to be executed.</param>
/// <param name="parameters">Parameters to pass to the method.</param>
/// <returns>An object that you can "await" to get the method return value.</returns>
public ObjectMethodExecutorAwaitable ExecuteAsync(object target, params object[] parameters)
{
return _executorAsync(target, parameters);
}

public object GetDefaultValueForParameter(int index)
{
if (_parameterDefaultValues == null)
{
throw new InvalidOperationException($"Cannot call {nameof(GetDefaultValueForParameter)}, because no parameter default values were supplied.");
}

if (index < 0 || index > MethodParameters.Length - 1)
{
throw new ArgumentOutOfRangeException(nameof(index));
}

return _parameterDefaultValues[index];
}

private static MethodExecutor GetExecutor(MethodInfo methodInfo, TypeInfo targetTypeInfo)
{
// Parameters to executor
var targetParameter = Expression.Parameter(typeof(object), "target");
var parametersParameter = Expression.Parameter(typeof(object[]), "parameters");

// Build parameter list
var parameters = new List<Expression>();
var paramInfos = methodInfo.GetParameters();
for (int i = 0; i < paramInfos.Length; i++)
{
var paramInfo = paramInfos[i];
var valueObj = Expression.ArrayIndex(parametersParameter, Expression.Constant(i));
var valueCast = Expression.Convert(valueObj, paramInfo.ParameterType);

// valueCast is "(Ti) parameters[i]"
parameters.Add(valueCast);
}

// Call method
var instanceCast = Expression.Convert(targetParameter, targetTypeInfo.AsType());
var methodCall = Expression.Call(instanceCast, methodInfo, parameters);

// methodCall is "((Ttarget) target) method((T0) parameters[0], (T1) parameters[1], ...)"
// Create function
if (methodCall.Type == typeof(void))
{
var lambda = Expression.Lambda<VoidMethodExecutor>(methodCall, targetParameter, parametersParameter);
var voidExecutor = lambda.Compile();
return WrapVoidMethod(voidExecutor);
}
else
{
// must coerce methodCall to match ActionExecutor signature
var castMethodCall = Expression.Convert(methodCall, typeof(object));
var lambda = Expression.Lambda<MethodExecutor>(castMethodCall, targetParameter, parametersParameter);
return lambda.Compile();
}
}

private static MethodExecutor WrapVoidMethod(VoidMethodExecutor executor)
{
return delegate (object target, object[] parameters)
{
executor(target, parameters);
return null;
};
}

private static MethodExecutorAsync GetExecutorAsync(
MethodInfo methodInfo,
TypeInfo targetTypeInfo,
CoercedAwaitableInfo coercedAwaitableInfo)
{
// Parameters to executor
var targetParameter = Expression.Parameter(typeof(object), "target");
var parametersParameter = Expression.Parameter(typeof(object[]), "parameters");

// Build parameter list
var parameters = new List<Expression>();
var paramInfos = methodInfo.GetParameters();
for (int i = 0; i < paramInfos.Length; i++)
{
var paramInfo = paramInfos[i];
var valueObj = Expression.ArrayIndex(parametersParameter, Expression.Constant(i));
var valueCast = Expression.Convert(valueObj, paramInfo.ParameterType);

// valueCast is "(Ti) parameters[i]"
parameters.Add(valueCast);
}

// Call method
var instanceCast = Expression.Convert(targetParameter, targetTypeInfo.AsType());
var methodCall = Expression.Call(instanceCast, methodInfo, parameters);

// Using the method return value, construct an ObjectMethodExecutorAwaitable based on
// the info we have about its implementation of the awaitable pattern. Note that all
// the funcs/actions we construct here are precompiled, so that only one instance of
// each is preserved throughout the lifetime of the ObjectMethodExecutor.

// var getAwaiterFunc = (object awaitable) =>
// (object)((CustomAwaitableType)awaitable).GetAwaiter();
var customAwaitableParam = Expression.Parameter(typeof(object), "awaitable");
var awaitableInfo = coercedAwaitableInfo.AwaitableInfo;
var postCoercionMethodReturnType = coercedAwaitableInfo.CoercerResultType ?? methodInfo.ReturnType;
var getAwaiterFunc = Expression.Lambda<Func<object, object>>(
Expression.Convert(
Expression.Call(
Expression.Convert(customAwaitableParam, postCoercionMethodReturnType),
awaitableInfo.GetAwaiterMethod),
typeof(object)),
customAwaitableParam).Compile();

// var isCompletedFunc = (object awaiter) =>
// ((CustomAwaiterType)awaiter).IsCompleted;
var isCompletedParam = Expression.Parameter(typeof(object), "awaiter");
var isCompletedFunc = Expression.Lambda<Func<object, bool>>(
Expression.MakeMemberAccess(
Expression.Convert(isCompletedParam, awaitableInfo.AwaiterType),
awaitableInfo.AwaiterIsCompletedProperty),
isCompletedParam).Compile();

var getResultParam = Expression.Parameter(typeof(object), "awaiter");
Func<object, object> getResultFunc;
if (awaitableInfo.ResultType == typeof(void))
{
// var getResultFunc = (object awaiter) =>
// {
// ((CustomAwaiterType)awaiter).GetResult(); // We need to invoke this to surface any exceptions
// return (object)null;
// };
getResultFunc = Expression.Lambda<Func<object, object>>(
Expression.Block(
Expression.Call(
Expression.Convert(getResultParam, awaitableInfo.AwaiterType),
awaitableInfo.AwaiterGetResultMethod),
Expression.Constant(null)
),
getResultParam).Compile();
}
else
{
// var getResultFunc = (object awaiter) =>
// (object)((CustomAwaiterType)awaiter).GetResult();
getResultFunc = Expression.Lambda<Func<object, object>>(
Expression.Convert(
Expression.Call(
Expression.Convert(getResultParam, awaitableInfo.AwaiterType),
awaitableInfo.AwaiterGetResultMethod),
typeof(object)),
getResultParam).Compile();
}

// var onCompletedFunc = (object awaiter, Action continuation) => {
// ((CustomAwaiterType)awaiter).OnCompleted(continuation);
// };
var onCompletedParam1 = Expression.Parameter(typeof(object), "awaiter");
var onCompletedParam2 = Expression.Parameter(typeof(Action), "continuation");
var onCompletedFunc = Expression.Lambda<Action<object, Action>>(
Expression.Call(
Expression.Convert(onCompletedParam1, awaitableInfo.AwaiterType),
awaitableInfo.AwaiterOnCompletedMethod,
onCompletedParam2),
onCompletedParam1,
onCompletedParam2).Compile();

Action<object, Action> unsafeOnCompletedFunc = null;
if (awaitableInfo.AwaiterUnsafeOnCompletedMethod != null)
{
// var unsafeOnCompletedFunc = (object awaiter, Action continuation) => {
// ((CustomAwaiterType)awaiter).UnsafeOnCompleted(continuation);
// };
var unsafeOnCompletedParam1 = Expression.Parameter(typeof(object), "awaiter");
var unsafeOnCompletedParam2 = Expression.Parameter(typeof(Action), "continuation");
unsafeOnCompletedFunc = Expression.Lambda<Action<object, Action>>(
Expression.Call(
Expression.Convert(unsafeOnCompletedParam1, awaitableInfo.AwaiterType),
awaitableInfo.AwaiterUnsafeOnCompletedMethod,
unsafeOnCompletedParam2),
unsafeOnCompletedParam1,
unsafeOnCompletedParam2).Compile();
}

// If we need to pass the method call result through a coercer function to get an
// awaitable, then do so.
var coercedMethodCall = coercedAwaitableInfo.RequiresCoercion
? Expression.Invoke(coercedAwaitableInfo.CoercerExpression, methodCall)
: (Expression)methodCall;

// return new ObjectMethodExecutorAwaitable(
// (object)coercedMethodCall,
// getAwaiterFunc,
// isCompletedFunc,
// getResultFunc,
// onCompletedFunc,
// unsafeOnCompletedFunc);
var returnValueExpression = Expression.New(
_objectMethodExecutorAwaitableConstructor,
Expression.Convert(coercedMethodCall, typeof(object)),
Expression.Constant(getAwaiterFunc),
Expression.Constant(isCompletedFunc),
Expression.Constant(getResultFunc),
Expression.Constant(onCompletedFunc),
Expression.Constant(unsafeOnCompletedFunc, typeof(Action<object, Action>)));

var lambda = Expression.Lambda<MethodExecutorAsync>(returnValueExpression, targetParameter, parametersParameter);
return lambda.Compile();
}
}
}

+ 114
- 0
src/DotNetCore.CAP/Internal/ObjectMethodExecutor/ObjectMethodExecutorAwaitable.cs Просмотреть файл

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// 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.Runtime.CompilerServices;

namespace Microsoft.Extensions.Internal
{
/// <summary>
/// Provides a common awaitable structure that <see cref="ObjectMethodExecutor.ExecuteAsync"/> can
/// return, regardless of whether the underlying value is a System.Task, an FSharpAsync, or an
/// application-defined custom awaitable.
/// </summary>
internal struct ObjectMethodExecutorAwaitable
{
private readonly object _customAwaitable;
private readonly Func<object, object> _getAwaiterMethod;
private readonly Func<object, bool> _isCompletedMethod;
private readonly Func<object, object> _getResultMethod;
private readonly Action<object, Action> _onCompletedMethod;
private readonly Action<object, Action> _unsafeOnCompletedMethod;

// Perf note: since we're requiring the customAwaitable to be supplied here as an object,
// this will trigger a further allocation if it was a value type (i.e., to box it). We can't
// fix this by making the customAwaitable type generic, because the calling code typically
// does not know the type of the awaitable/awaiter at compile-time anyway.
//
// However, we could fix it by not passing the customAwaitable here at all, and instead
// passing a func that maps directly from the target object (e.g., controller instance),
// target method (e.g., action method info), and params array to the custom awaiter in the
// GetAwaiter() method below. In effect, by delaying the actual method call until the
// upstream code calls GetAwaiter on this ObjectMethodExecutorAwaitable instance.
// This optimization is not currently implemented because:
// [1] It would make no difference when the awaitable was an object type, which is
// by far the most common scenario (e.g., System.Task<T>).
// [2] It would be complex - we'd need some kind of object pool to track all the parameter
// arrays until we needed to use them in GetAwaiter().
// We can reconsider this in the future if there's a need to optimize for ValueTask<T>
// or other value-typed awaitables.

public ObjectMethodExecutorAwaitable(
object customAwaitable,
Func<object, object> getAwaiterMethod,
Func<object, bool> isCompletedMethod,
Func<object, object> getResultMethod,
Action<object, Action> onCompletedMethod,
Action<object, Action> unsafeOnCompletedMethod)
{
_customAwaitable = customAwaitable;
_getAwaiterMethod = getAwaiterMethod;
_isCompletedMethod = isCompletedMethod;
_getResultMethod = getResultMethod;
_onCompletedMethod = onCompletedMethod;
_unsafeOnCompletedMethod = unsafeOnCompletedMethod;
}

public Awaiter GetAwaiter()
{
var customAwaiter = _getAwaiterMethod(_customAwaitable);
return new Awaiter(customAwaiter, _isCompletedMethod, _getResultMethod, _onCompletedMethod, _unsafeOnCompletedMethod);
}

public struct Awaiter : ICriticalNotifyCompletion
{
private readonly object _customAwaiter;
private readonly Func<object, bool> _isCompletedMethod;
private readonly Func<object, object> _getResultMethod;
private readonly Action<object, Action> _onCompletedMethod;
private readonly Action<object, Action> _unsafeOnCompletedMethod;

public Awaiter(
object customAwaiter,
Func<object, bool> isCompletedMethod,
Func<object, object> getResultMethod,
Action<object, Action> onCompletedMethod,
Action<object, Action> unsafeOnCompletedMethod)
{
_customAwaiter = customAwaiter;
_isCompletedMethod = isCompletedMethod;
_getResultMethod = getResultMethod;
_onCompletedMethod = onCompletedMethod;
_unsafeOnCompletedMethod = unsafeOnCompletedMethod;
}

public bool IsCompleted => _isCompletedMethod(_customAwaiter);

public object GetResult() => _getResultMethod(_customAwaiter);

public void OnCompleted(Action continuation)
{
_onCompletedMethod(_customAwaiter, continuation);
}

public void UnsafeOnCompleted(Action continuation)
{
// If the underlying awaitable implements ICriticalNotifyCompletion, use its UnsafeOnCompleted.
// If not, fall back on using its OnCompleted.
//
// Why this is safe:
// - Implementing ICriticalNotifyCompletion is a way of saying the caller can choose whether it
// needs the execution context to be preserved (which it signals by calling OnCompleted), or
// that it doesn't (which it signals by calling UnsafeOnCompleted). Obviously it's faster *not*
// to preserve and restore the context, so we prefer that where possible.
// - If a caller doesn't need the execution context to be preserved and hence calls UnsafeOnCompleted,
// there's no harm in preserving it anyway - it's just a bit of wasted cost. That's what will happen
// if a caller sees that the proxy implements ICriticalNotifyCompletion but the proxy chooses to
// pass the call on to the underlying awaitable's OnCompleted method.

var underlyingMethodToUse = _unsafeOnCompletedMethod ?? _onCompletedMethod;
underlyingMethodToUse(_customAwaiter, continuation);
}
}
}
}

+ 151
- 0
src/DotNetCore.CAP/Internal/ObjectMethodExecutor/ObjectMethodExecutorFSharpSupport.cs Просмотреть файл

@@ -0,0 +1,151 @@
// 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.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.Extensions.Internal
{
/// <summary>
/// Helper for detecting whether a given type is FSharpAsync`1, and if so, supplying
/// an <see cref="Expression"/> for mapping instances of that type to a C# awaitable.
/// </summary>
/// <remarks>
/// The main design goal here is to avoid taking a compile-time dependency on
/// FSharp.Core.dll, because non-F# applications wouldn't use it. So all the references
/// to FSharp types have to be constructed dynamically at runtime.
/// </remarks>
internal static class ObjectMethodExecutorFSharpSupport
{
private static object _fsharpValuesCacheLock = new object();
private static Assembly _fsharpCoreAssembly;
private static MethodInfo _fsharpAsyncStartAsTaskGenericMethod;
private static PropertyInfo _fsharpOptionOfTaskCreationOptionsNoneProperty;
private static PropertyInfo _fsharpOptionOfCancellationTokenNoneProperty;

public static bool TryBuildCoercerFromFSharpAsyncToAwaitable(
Type possibleFSharpAsyncType,
out Expression coerceToAwaitableExpression,
out Type awaitableType)
{
var methodReturnGenericType = possibleFSharpAsyncType.IsGenericType
? possibleFSharpAsyncType.GetGenericTypeDefinition()
: null;

if (!IsFSharpAsyncOpenGenericType(methodReturnGenericType))
{
coerceToAwaitableExpression = null;
awaitableType = null;
return false;
}

var awaiterResultType = possibleFSharpAsyncType.GetGenericArguments().Single();
awaitableType = typeof(Task<>).MakeGenericType(awaiterResultType);

// coerceToAwaitableExpression = (object fsharpAsync) =>
// {
// return (object)FSharpAsync.StartAsTask<TResult>(
// (Microsoft.FSharp.Control.FSharpAsync<TResult>)fsharpAsync,
// FSharpOption<TaskCreationOptions>.None,
// FSharpOption<CancellationToken>.None);
// };
var startAsTaskClosedMethod = _fsharpAsyncStartAsTaskGenericMethod
.MakeGenericMethod(awaiterResultType);
var coerceToAwaitableParam = Expression.Parameter(typeof(object));
coerceToAwaitableExpression = Expression.Lambda(
Expression.Convert(
Expression.Call(
startAsTaskClosedMethod,
Expression.Convert(coerceToAwaitableParam, possibleFSharpAsyncType),
Expression.MakeMemberAccess(null, _fsharpOptionOfTaskCreationOptionsNoneProperty),
Expression.MakeMemberAccess(null, _fsharpOptionOfCancellationTokenNoneProperty)),
typeof(object)),
coerceToAwaitableParam);

return true;
}

private static bool IsFSharpAsyncOpenGenericType(Type possibleFSharpAsyncGenericType)
{
var typeFullName = possibleFSharpAsyncGenericType?.FullName;
if (!string.Equals(typeFullName, "Microsoft.FSharp.Control.FSharpAsync`1", StringComparison.Ordinal))
{
return false;
}

lock (_fsharpValuesCacheLock)
{
if (_fsharpCoreAssembly != null)
{
// Since we've already found the real FSharpAsync.Core assembly, we just have
// to check that the supplied FSharpAsync`1 type is the one from that assembly.
return possibleFSharpAsyncGenericType.Assembly == _fsharpCoreAssembly;
}
else
{
// We'll keep trying to find the FSharp types/values each time any type called
// FSharpAsync`1 is supplied.
return TryPopulateFSharpValueCaches(possibleFSharpAsyncGenericType);
}
}
}

private static bool TryPopulateFSharpValueCaches(Type possibleFSharpAsyncGenericType)
{
var assembly = possibleFSharpAsyncGenericType.Assembly;
var fsharpOptionType = assembly.GetType("Microsoft.FSharp.Core.FSharpOption`1");
var fsharpAsyncType = assembly.GetType("Microsoft.FSharp.Control.FSharpAsync");

if (fsharpOptionType == null || fsharpAsyncType == null)
{
return false;
}

// Get a reference to FSharpOption<TaskCreationOptions>.None
var fsharpOptionOfTaskCreationOptionsType = fsharpOptionType
.MakeGenericType(typeof(TaskCreationOptions));
_fsharpOptionOfTaskCreationOptionsNoneProperty = fsharpOptionOfTaskCreationOptionsType
.GetTypeInfo()
.GetRuntimeProperty("None");

// Get a reference to FSharpOption<CancellationToken>.None
var fsharpOptionOfCancellationTokenType = fsharpOptionType
.MakeGenericType(typeof(CancellationToken));
_fsharpOptionOfCancellationTokenNoneProperty = fsharpOptionOfCancellationTokenType
.GetTypeInfo()
.GetRuntimeProperty("None");

// Get a reference to FSharpAsync.StartAsTask<>
var fsharpAsyncMethods = fsharpAsyncType
.GetRuntimeMethods()
.Where(m => m.Name.Equals("StartAsTask", StringComparison.Ordinal));
foreach (var candidateMethodInfo in fsharpAsyncMethods)
{
var parameters = candidateMethodInfo.GetParameters();
if (parameters.Length == 3
&& TypesHaveSameIdentity(parameters[0].ParameterType, possibleFSharpAsyncGenericType)
&& parameters[1].ParameterType == fsharpOptionOfTaskCreationOptionsType
&& parameters[2].ParameterType == fsharpOptionOfCancellationTokenType)
{
// This really does look like the correct method (and hence assembly).
_fsharpAsyncStartAsTaskGenericMethod = candidateMethodInfo;
_fsharpCoreAssembly = assembly;
break;
}
}

return _fsharpCoreAssembly != null;
}

private static bool TypesHaveSameIdentity(Type type1, Type type2)
{
return type1.Assembly == type2.Assembly
&& string.Equals(type1.Namespace, type2.Namespace, StringComparison.Ordinal)
&& string.Equals(type1.Name, type2.Name, StringComparison.Ordinal);
}
}
}

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