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Api renewals #5

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merged 9 commits into from
Dec 19, 2016
Merged

Api renewals #5

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7a0a30b
change constructor accessibility, from public to internal
acple Dec 15, 2016
e143e5f
make 'Task' property to null-safe
acple Dec 15, 2016
db13696
add 'Wait' method and 'Result' property
acple Dec 15, 2016
3cc1b45
add 'ConfigureAwait' method
acple Dec 15, 2016
8efec9e
change api 'ConfigureAwait(bool)' -> 'EnableContextCapture()'
acple Dec 15, 2016
fc69347
use lambda-bodied constructor
acple Dec 15, 2016
865d091
change AsyncMethodBuilderAttribute accessibility
acple Dec 15, 2016
910ba64
namespace restructure
acple Dec 15, 2016
7d3f85b
Revert "change api 'ConfigureAwait(bool)' -> 'EnableContextCapture()'"
acple Dec 19, 2016
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7 changes: 5 additions & 2 deletions src/ContextFreeTasks.Shared/ContextFreeTask.cs
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Original file line number Diff line number Diff line change
@@ -1,13 +1,16 @@
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
using static System.Threading.Tasks.Task;

namespace ContextFreeTasks
{
[AsyncMethodBuilder(typeof(AsyncContextFreeTaskMethodBuilder))]
public struct ContextFreeTask
{
public Task Task { get; }
public ContextFreeTask(Task t) => Task = t;
private readonly Task _task;
public Task Task => _task ?? FromResult(default(object));
internal ContextFreeTask(Task t) => _task = t;
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@ufcpp ufcpp Dec 16, 2016 •
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So far, await on null should throw an Exception. For the purpose of null-safety, the constructor should throw an exception if t is null and _task should not be null. Of course, default(ContextFreeTask) makes _task be null, but, it is misuse.

I hope the following proposals:

dotnet/roslyn#7171
dotnet/roslyn#15108

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Yes, I concerned about default(ContextFreeTask). if provides struct as public, we must consider the default.
for example, ValueTask created with default keyword, it is same as FromResult(default(T)).
the constructor of ContextFreeTask is hid to internal. so ONLY default(ContextFreeTask) makes _task be null. it's very rare case.

public ContextFreeTaskAwaiter GetAwaiter() => new ContextFreeTaskAwaiter(Task);
public void Wait() => _task?.Wait();
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@ufcpp ufcpp Dec 16, 2016 •
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This is by design. Users should use GetAwaiter().GetResult() instead of Wait(). The ValueTask doesn't have Wait too.

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in my opinion, naming of 'ContextFree' includes the meaning 'This can blocking-wait safely'.
Task and ValueTask should not use blocking-wait, but ContextFreeTask doesn't.
It is possible but, of course I think that is better not to use.

}
}
8 changes: 6 additions & 2 deletions src/ContextFreeTasks.Shared/ContextFreeTask_T.cs
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Original file line number Diff line number Diff line change
@@ -1,13 +1,17 @@
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
using static System.Threading.Tasks.Task;

namespace ContextFreeTasks
{
[AsyncMethodBuilder(typeof(AsyncContextFreeTaskMethodBuilder<>))]
public struct ContextFreeTask<T>
{
public Task<T> Task { get; }
public ContextFreeTask(Task<T> t) => Task = t;
private readonly Task<T> _task;
public Task<T> Task => _task ?? FromResult(default(T));
public T Result => GetAwaiter().GetResult();
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This is uneasy. For consistency with ValueTask, the Result should be implemented like this. However, I don't prefer blocking wait.
If breaking change is allowed, I really want the Task.Result to throw an exception instead of blocking wait when it has not completed yet.

internal ContextFreeTask(Task<T> t) => _task = t;
public ContextFreeTaskAwaiter<T> GetAwaiter() => new ContextFreeTaskAwaiter<T>(Task);
public void Wait() => _task?.Wait();
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by design, no Wait

}
}