execute_child_on_await.swift

// RUN: %target-run-simple-swift(-parse-as-library -target %target-swift-5.1-abi-triple -Xfrontend -concurrency-model=task-to-thread -g -Xlinker -object_path_lto -Xlinker /tmp/abc.o)

// REQUIRES: concurrency
// REQUIRES: executable_test
// REQUIRES: freestanding
// REQUIRES: concurrency_runtime

@_spi(_TaskToThreadModel)import _Concurrency
import StdlibUnittest
import Darwin

vara=0;

func foo()async->Int{
 a +=1
print("a is now \(a)")
return a
}

func bar()async->Int{
 a +=2
print("a is now \(a)")
return a
}

func asyncFib(_ n:Int, _ expected_thread:pthread_t)async->Int{
expectEqual(pthread_self(), expected_thread);

if n ==0 || n ==1{
return n
}

asyncletfirst=asyncFib(n-2, expected_thread)
asyncletsecond=asyncFib(n-1, expected_thread)

return(await second)+(await first)
}

func fib(_ n:Int)->Int{
varfirst=0
varsecond=1
for_in0..<n {
lettemp= first
 first = second
 second = temp + first
}
return first
}

@mainstructMain{
staticfunc main(){

lettests=TestSuite("Execute child task on await")
 tests.test("Basic async let only execute on await"){
Task.runInline{
asyncleta=foo()
asyncletb=bar()

expectEqual(await b,2)
expectEqual(await a,3)
 // Re-querying a completed task should return original result and not
 // reexecute it
expectEqual(await b,2)
}
}

 tests.test("Nested async lets that only execute on await"){
Task.runInline{
letresult=awaitasyncFib(10,pthread_self())
expectEqual(result,fib(10))
}
}

 tests.test("Task group execute child task on await simple"){
 a =0
Task.runInline{
awaitwithTaskGroup(of:Int.self, body :{ group in
letcurrentThread=pthread_self()
 group.addTask{
expectEqual(pthread_self(), currentThread);
returnawaitfoo()
}

 group.addTask{
expectEqual(pthread_self(), currentThread);
returnawaitbar()
}
})
}
}

 tests.test("Task groups with nested structured concurrency"){
Task.runInline{
awaitwithTaskGroup(of:Int.self, body :{ group in
letcurrentThread=pthread_self()
 group.addTask{
returnawaitasyncFib(10, currentThread);
}

 group.addTask{
returnawaitasyncFib(5, currentThread);
}
})
}
}

runAllTests()
}
}