1 files changed, 40 insertions, 0 deletions
diff --git a/third_party/rust/uniffi_bindgen/src/bindings/python/templates/Async.py b/third_party/rust/uniffi_bindgen/src/bindings/python/templates/Async.py
new file mode 100644
index 0000000000..82aa534b46
--- /dev/null
+++ b/third_party/rust/uniffi_bindgen/src/bindings/python/templates/Async.py
@@ -0,0 +1,40 @@
+# RustFuturePoll values
+_UNIFFI_RUST_FUTURE_POLL_READY = 0
+_UNIFFI_RUST_FUTURE_POLL_MAYBE_READY = 1
+
+# Stores futures for _uniffi_continuation_callback
+_UniffiContinuationPointerManager = _UniffiPointerManager()
+
+# Continuation callback for async functions
+# lift the return value or error and resolve the future, causing the async function to resume.
+@_UNIFFI_FUTURE_CONTINUATION_T
+def _uniffi_continuation_callback(future_ptr, poll_code):
+    (eventloop, future) = _UniffiContinuationPointerManager.release_pointer(future_ptr)
+    eventloop.call_soon_threadsafe(_uniffi_set_future_result, future, poll_code)
+
+def _uniffi_set_future_result(future, poll_code):
+    if not future.cancelled():
+        future.set_result(poll_code)
+
+async def _uniffi_rust_call_async(rust_future, ffi_poll, ffi_complete, ffi_free, lift_func, error_ffi_converter):
+    try:
+        eventloop = asyncio.get_running_loop()
+
+        # Loop and poll until we see a _UNIFFI_RUST_FUTURE_POLL_READY value
+        while True:
+            future = eventloop.create_future()
+            ffi_poll(
+                rust_future,
+                _UniffiContinuationPointerManager.new_pointer((eventloop, future)),
+            )
+            poll_code = await future
+            if poll_code == _UNIFFI_RUST_FUTURE_POLL_READY:
+                break
+
+        return lift_func(
+            _rust_call_with_error(error_ffi_converter, ffi_complete, rust_future)
+        )
+    finally:
+        ffi_free(rust_future)
+
+_UniffiLib.{{ ci.ffi_rust_future_continuation_callback_set().name() }}(_uniffi_continuation_callback)