Initial wrapping of kj/async Promises and EventLoop

capnp/async.pyx

@@ -0,0 +1,54 @@
+# capnp.pyx
+# distutils: language = c++
+# distutils: extra_compile_args = --std=c++11 -fpermissive
+# distutils: libraries = kj
+# cython: c_string_type = str
+# cython: c_string_encoding = default
+# cython: embedsignature = True
+
+cimport cython
+cimport async_cpp as async
+from cpython.ref cimport PyObject, Py_INCREF, Py_DECREF
+from cython.operator cimport dereference as deref
+
+cdef extern from "<utility>" namespace "std":
+    async.PyPromise movePromise"std::move"(async.PyPromise)
+
+# This is a really weird function. By making it public, we'll be able to call it from asyncHelper.h
+cdef public object wrap_kj_exception(async.Exception & exception):
+    return None # TODO
+
+cdef class EventLoop:
+    cdef async.SimpleEventLoop thisptr
+
+    cpdef evalLater(self, func):
+        Py_INCREF(func)
+        return Promise()._init(async.evalLater(self.thisptr, <PyObject *>func))
+
+    cdef wait(self, async.PyPromise * promise):
+        return self.thisptr.wait(movePromise(deref(promise)))
+
+    cdef there(self, async.PyPromise * promise, object func, object error_func):
+        Py_INCREF(func)
+        Py_INCREF(error_func)
+        return Promise()._init(async.there(self.thisptr, deref(promise), <PyObject *>func, <PyObject *>error_func))
+
+
+cdef EventLoop c_event_loop = EventLoop()
+event_loop = c_event_loop
+
+cdef class Promise:
+    cdef async.PyPromise * thisptr
+    cdef _init(self, async.PyPromise other):
+        self.thisptr = new async.PyPromise(movePromise(other))
+        return self
+
+    def __dealloc__(self):
+        del self.thisptr
+
+    def wait(self):
+        return c_event_loop.wait(self.thisptr)
+
+    def then(self, func, error_func=None):
+        return c_event_loop.there(self.thisptr, func, error_func)
+