Make via a free function

Reviewed By: yfeldblum

Differential Revision: D7203193

fbshipit-source-id: 440daa2f79a919aa95ae3fdb4006f8d501c0ad93

folly/experimental/coro/Task.h

@@ -46,7 +46,7 @@ class Task {
     DCHECK(!promise_);
   }
 
-  Future<T> via(folly::Executor* executor) && {
+  Future<T> scheduleVia(folly::Executor* executor) && {
     promise_->executor_ = executor;
     promise_->executor_->add([promise = promise_] { promise->start(); });
     return {*std::exchange(promise_, nullptr)};
@@ -66,5 +66,12 @@ class Task {
 
   Promise<T>* promise_;
 };
+
 } // namespace coro
+
+template <typename T>
+coro::Future<T> via(folly::Executor* executor, coro::Task<T>&& task) {
+  return std::move(task).scheduleVia(executor);
+}
+
 } // namespace folly

folly/experimental/coro/tests/CoroTest.cpp

@@ -26,7 +26,7 @@ coro::Task<int> task42() {
 
 TEST(Coro, Basic) {
   ManualExecutor executor;
-  auto future = task42().via(&executor);
+  auto future = via(&executor, task42());
 
   EXPECT_FALSE(future.await_ready());
 
@@ -61,7 +61,7 @@ TEST(Coro, Sleep) {
   ScopedEventBaseThread evbThread;
 
   auto startTime = std::chrono::steady_clock::now();
-  auto future = taskSleep().via(evbThread.getEventBase());
+  auto future = via(evbThread.getEventBase(), taskSleep());
 
   EXPECT_FALSE(future.await_ready());
 
@@ -79,7 +79,7 @@ coro::Task<void> taskException() {
 
 TEST(Coro, Throw) {
   ManualExecutor executor;
-  auto future = taskException().via(&executor);
+  auto future = via(&executor, taskException());
 
   EXPECT_FALSE(future.await_ready());
 
@@ -101,7 +101,7 @@ coro::Task<int> taskRecursion(int depth) {
 
 TEST(Coro, LargeStack) {
   ScopedEventBaseThread evbThread;
-  auto future = taskRecursion(10000).via(evbThread.getEventBase());
+  auto future = via(evbThread.getEventBase(), taskRecursion(10000));
 
   future.wait();
   EXPECT_EQ(10000, future.get());
@@ -118,8 +118,8 @@ coro::Task<int> taskThread() {
   auto threadId = std::this_thread::get_id();
 
   folly::ScopedEventBaseThread evbThread;
-  co_await taskThreadNested(evbThread.getThreadId())
-      .via(evbThread.getEventBase());
+  co_await via(
+      evbThread.getEventBase(), taskThreadNested(evbThread.getThreadId()));
 
   EXPECT_EQ(threadId, std::this_thread::get_id());
 
@@ -128,7 +128,7 @@ coro::Task<int> taskThread() {
 
 TEST(Coro, NestedThreads) {
   ScopedEventBaseThread evbThread;
-  auto future = taskThread().via(evbThread.getEventBase());
+  auto future = via(evbThread.getEventBase(), taskThread());
 
   future.wait();
   EXPECT_EQ(42, future.get());
@@ -138,7 +138,7 @@ coro::Task<int> taskYield(Executor* executor) {
   auto currentExecutor = co_await coro::getCurrentExecutor();
   EXPECT_EQ(executor, currentExecutor);
 
-  auto future = task42().via(currentExecutor);
+  auto future = via(currentExecutor, task42());
   EXPECT_FALSE(future.await_ready());
 
   co_await coro::yield();
@@ -150,7 +150,7 @@ coro::Task<int> taskYield(Executor* executor) {
 TEST(Coro, CurrentExecutor) {
   ScopedEventBaseThread evbThread;
   auto future =
-      taskYield(evbThread.getEventBase()).via(evbThread.getEventBase());
+      via(evbThread.getEventBase(), taskYield(evbThread.getEventBase()));
 
   future.wait();
   EXPECT_EQ(42, future.get());