/
AsyncInterceptorBase.cs
186 lines (161 loc) · 6.98 KB
/
AsyncInterceptorBase.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
// Copyright (c) 2016 James Skimming. All rights reserved.
// Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
namespace Castle.DynamicProxy
{
using System;
using System.Collections.Concurrent;
using System.Reflection;
using System.Threading.Tasks;
/// <summary>
/// A base type for an <see cref="IAsyncInterceptor"/> to provided a simplified solution of method
/// <see cref="IInvocation"/> by enforcing only two types of interception, both asynchronous.
/// </summary>
public abstract class AsyncInterceptorBase : IAsyncInterceptor
{
#if !NETSTANDARD2_0
/// <summary>
/// A completed <see cref="Task"/>.
/// </summary>
private static readonly Task CompletedTask = Task.FromResult(0);
#endif
private static readonly MethodInfo InterceptSynchronousMethodInfo =
typeof(AsyncInterceptorBase)
.GetMethod(nameof(InterceptSynchronousResult), BindingFlags.Static | BindingFlags.NonPublic);
private static readonly ConcurrentDictionary<Type, GenericSynchronousHandler> GenericSynchronousHandlers =
new ConcurrentDictionary<Type, GenericSynchronousHandler>
{
[typeof(void)] = InterceptSynchronousVoid,
};
private delegate void GenericSynchronousHandler(AsyncInterceptorBase me, IInvocation invocation);
/// <summary>
/// Intercepts a synchronous method <paramref name="invocation"/>.
/// </summary>
/// <param name="invocation">The method invocation.</param>
void IAsyncInterceptor.InterceptSynchronous(IInvocation invocation)
{
Type returnType = invocation.Method.ReturnType;
GenericSynchronousHandler handler = GenericSynchronousHandlers.GetOrAdd(returnType, CreateHandler);
handler(this, invocation);
}
/// <summary>
/// Intercepts an asynchronous method <paramref name="invocation"/> with return type of <see cref="Task"/>.
/// </summary>
/// <param name="invocation">The method invocation.</param>
void IAsyncInterceptor.InterceptAsynchronous(IInvocation invocation)
{
invocation.ReturnValue = InterceptAsync(invocation, ProceedAsynchronous);
}
/// <summary>
/// Intercepts an asynchronous method <paramref name="invocation"/> with return type of <see cref="Task{T}"/>.
/// </summary>
/// <typeparam name="TResult">The type of the <see cref="Task{T}"/> <see cref="Task{T}.Result"/>.</typeparam>
/// <param name="invocation">The method invocation.</param>
void IAsyncInterceptor.InterceptAsynchronous<TResult>(IInvocation invocation)
{
invocation.ReturnValue = InterceptAsync(invocation, ProceedAsynchronous<TResult>);
}
/// <summary>
/// Override in derived classes to intercept method invocations.
/// </summary>
/// <param name="invocation">The method invocation.</param>
/// <param name="proceed">The function to proceed the <paramref name="invocation"/>.</param>
/// <returns>A <see cref="Task" /> object that represents the asynchronous operation.</returns>
protected abstract Task InterceptAsync(IInvocation invocation, Func<IInvocation, Task> proceed);
/// <summary>
/// Override in derived classes to intercept method invocations.
/// </summary>
/// <typeparam name="TResult">The type of the <see cref="Task{T}"/> <see cref="Task{T}.Result"/>.</typeparam>
/// <param name="invocation">The method invocation.</param>
/// <param name="proceed">The function to proceed the <paramref name="invocation"/>.</param>
/// <returns>A <see cref="Task" /> object that represents the asynchronous operation.</returns>
protected abstract Task<TResult> InterceptAsync<TResult>(
IInvocation invocation,
Func<IInvocation, Task<TResult>> proceed);
private static GenericSynchronousHandler CreateHandler(Type returnType)
{
MethodInfo method = InterceptSynchronousMethodInfo.MakeGenericMethod(returnType);
return (GenericSynchronousHandler)method.CreateDelegate(typeof(GenericSynchronousHandler));
}
private static void InterceptSynchronousVoid(AsyncInterceptorBase me, IInvocation invocation)
{
Task task = me.InterceptAsync(invocation, ProceedSynchronous);
// If the intercept task has yet to complete, wait for it.
if (!task.IsCompleted)
{
Task.Run(() => task).Wait();
}
if (task.IsFaulted)
{
throw task.Exception.InnerException;
}
}
private static void InterceptSynchronousResult<TResult>(AsyncInterceptorBase me, IInvocation invocation)
{
Task task = me.InterceptAsync(invocation, ProceedSynchronous<TResult>);
// If the intercept task has yet to complete, wait for it.
if (!task.IsCompleted)
{
Task.Run(() => task).Wait();
}
if (task.IsFaulted)
{
throw task.Exception.InnerException;
}
}
private static Task ProceedSynchronous(IInvocation invocation)
{
try
{
invocation.Proceed();
#if NETSTANDARD2_0
return Task.CompletedTask;
#else
return CompletedTask;
#endif
}
catch (Exception e)
{
#if NETSTANDARD2_0
return Task.FromException(e);
#else
var tcs = new TaskCompletionSource<int>();
tcs.SetException(e);
return tcs.Task;
#endif
}
}
private static Task<TResult> ProceedSynchronous<TResult>(IInvocation invocation)
{
try
{
invocation.Proceed();
return Task.FromResult((TResult)invocation.ReturnValue);
}
catch (Exception e)
{
#if NETSTANDARD2_0
return Task.FromException<TResult>(e);
#else
var tcs = new TaskCompletionSource<TResult>();
tcs.SetException(e);
return tcs.Task;
#endif
}
}
private static async Task ProceedAsynchronous(IInvocation invocation)
{
invocation.Proceed();
// Get the task to await.
var originalReturnValue = (Task)invocation.ReturnValue;
await originalReturnValue.ConfigureAwait(false);
}
private static async Task<TResult> ProceedAsynchronous<TResult>(IInvocation invocation)
{
invocation.Proceed();
// Get the task to await.
var originalReturnValue = (Task<TResult>)invocation.ReturnValue;
TResult result = await originalReturnValue.ConfigureAwait(false);
return result;
}
}
}