public static Task <TR> SelectMany <TI, TC, TR>(this Task <TI> task, Func <TI, Task <TC> > selector, Func <TI, TC, TR> projector)
{
var taskSource = new TaskCompletionSource <TR>();
taskSource.SetResultFromTask(task, (ts, taskResult) => ts.SetResultFromTaskSafe(() => selector(taskResult), (ts_, selectorResult) => ts_.SetResultSafe(() => projector(taskResult, selectorResult))));
return(taskSource.Task);
}
public static Task <TR> Select <TI, TR>(this Task <TI> task, Func <TI, TR> selector)
{
var taskSource = new TaskCompletionSource <TR>();
taskSource.SetResultFromTask(task, (ts, taskResult) => ts.SetResultSafe(() => selector(taskResult)));
return(taskSource.Task);
}
public static void SetResultFromTaskSafe <TI, TR>(this TaskCompletionSource <TR> taskSource, Func <Task <TI> > getTask, Action <TaskCompletionSource <TR>, TI> setResultAction)
{
Task <TI> task;
try {
task = getTask();
} catch (Exception e) {
taskSource.SetException(e);
return;
}
taskSource.SetResultFromTask(task, setResultAction);
}
public static Task <T> Where <T>(this Task <T> task, Func <T, bool> predicate)
{
var taskSource = new TaskCompletionSource <T>();
taskSource.SetResultFromTask(task, (ts, taskResult) => {
ts.SetResultSafe(() => predicate(taskResult), (ts_, predicateResult) => {
if (predicateResult)
{
ts_.SetResult(taskResult);
}
else
{
ts_.SetCanceled();
}
});
});
return(taskSource.Task);
}
public static void SetResultFromTask <T>(this TaskCompletionSource <T> taskSource, Task <T> task)
{
taskSource.SetResultFromTask(task, (ts, taskResult) => ts.SetResult(taskResult));
}
public static void SetResultFromTask <TI, TR>(this TaskCompletionSource <TR> taskSource, Task <TI> task, Action <TaskCompletionSource <TR>, TI> setResultAction)
{
taskSource.SetResultFromTask(task, setResultAction, x => x.SetCanceled());
}
