Add functions for bridging semi futures

Reviewed By: yfeldblum

Differential Revision: D14062156

fbshipit-source-id: 2cdc32fc9834bd165fa8011ca1d336edaf05f653

folly/python/__init__.pxd

@@ -18,6 +18,10 @@ cdef extern from "folly/futures/Future.h" namespace "folly" nogil:
         cbool isReady()
         #TODO add via and then
 
+    cdef cppclass cFollySemiFuture "folly::SemiFuture"[T]:
+        T get()
+        pass
+
 cdef extern from "folly/Unit.h" namespace "folly":
     struct cFollyUnit "folly::Unit":
         pass

folly/python/futures.h

@@ -64,5 +64,24 @@ void bridgeFuture(
       getExecutor(), std::move(futureFrom), std::move(callback), userData);
 }
 
+template <typename T>
+void bridgeSemiFuture(
+    folly::Executor* executor,
+    folly::SemiFuture<T>&& semiFutureFrom,
+    folly::Function<void(folly::Try<T>&&, PyObject*)> callback,
+    PyObject* userData) {
+  folly::Future<T> futureFrom = std::move(semiFutureFrom).via(executor);
+  bridgeFuture(executor, std::move(futureFrom), std::move(callback), userData);
+}
+
+template <typename T>
+void bridgeSemiFuture(
+    folly::SemiFuture<T>&& semiFutureFrom,
+    folly::Function<void(folly::Try<T>&&, PyObject*)> callback,
+    PyObject* userData) {
+  bridgeSemiFuture(
+      getExecutor(), std::move(semiFutureFrom), std::move(callback), userData);
+}
+
 } // namespace python
 } // namespace folly

folly/python/futures.pxd

 from cpython.ref cimport PyObject
-from folly cimport cFollyTry, cFollyFuture, cFollyExecutor
+from folly cimport cFollyTry, cFollyFuture, cFollyExecutor, cFollySemiFuture
 
 cdef extern from "folly/python/futures.h" namespace "folly::python":
     void bridgeFuture[T](
@@ -14,3 +14,15 @@ cdef extern from "folly/python/futures.h" namespace "folly::python":
         void(*)(cFollyTry[T]&&, PyObject*),
         PyObject* pyFuture
     )
+    void bridgeSemiFuture[T](
+        cFollySemiFuture[T]&& fut,
+        void(*)(cFollyTry[T]&&, PyObject*),
+        PyObject* pyFuture
+    )
+    # No clue but cython overloading is getting confused so we alias
+    void bridgeSemiFutureWith "folly::python::bridgeSemiFuture"[T](
+        cFollyExecutor* executor,
+        cFollySemiFuture[T]&& fut,
+        void(*)(cFollyTry[T]&&, PyObject*),
+        PyObject* pyFuture
+    )

folly/python/test/futures.py

@@ -12,6 +12,12 @@ class Futures(unittest.TestCase):
         res = loop.run_until_complete(simplebridge.get_value_x5(val))
         self.assertEqual(val * 5, res)
 
+    def test_bridge_semifuture(self):
+        val = 1337
+        loop = asyncio.get_event_loop()
+        res = loop.run_until_complete(simplebridge.get_value_x5_semifuture(val))
+        self.assertEqual(val * 5, res)
+
     def test_bridge_exception(self):
         loop = asyncio.get_event_loop()
         with self.assertRaises(ValueError, msg="0 is not allowed"):

folly/python/test/simple.h

@@ -34,6 +34,18 @@ folly::Future<uint64_t> future_getValueX5(uint64_t val) {
   return f;
 }
 
+folly::SemiFuture<uint64_t> semiFuture_getValueX5(uint64_t val) {
+  folly::Promise<uint64_t> p;
+  auto f = p.getSemiFuture();
+  p.setWith([val] {
+    if (val == 0) {
+      throw std::invalid_argument("0 is not allowed");
+    }
+    return val * 5;
+  });
+  return f;
+}
+
 folly::Function<uint64_t()> getValueX5Fibers(uint64_t val) {
   return [val]() {
     if (val == 0) {

folly/python/test/simplebridge.pyx

 import asyncio
-from folly.futures cimport bridgeFuture
+from folly.futures cimport bridgeFuture, bridgeSemiFuture
 from folly.fibers cimport bridgeFibers
-from folly cimport cFollyFuture, cFollyTry
+from folly cimport cFollyFuture, cFollySemiFuture, cFollyTry
 from libc.stdint cimport uint64_t
 from cpython.ref cimport PyObject
 from cython.operator cimport dereference as deref
 
 cdef extern from "folly/python/test/simple.h" namespace "folly::python::test":
     cdef cFollyFuture[uint64_t] future_getValueX5(uint64_t val)
+    cdef cFollySemiFuture[uint64_t] semiFuture_getValueX5(uint64_t val)
     cdef (uint64_t(*)()) getValueX5Fibers(uint64_t val)
 
 
@@ -21,6 +22,15 @@ def get_value_x5(int val):
     )
     return fut
 
+def get_value_x5_semifuture(int val):
+    loop = asyncio.get_event_loop()
+    fut = loop.create_future()
+    bridgeSemiFuture[uint64_t](
+        semiFuture_getValueX5(val),
+        handle_uint64_t,
+        <PyObject *>fut
+    )
+    return fut
 
 def get_value_x5_fibers(int val):
     loop = asyncio.get_event_loop()