api(deltachat-rpc-client): add futures

futures allow to call multiple methods in parallel
without threads.

This introduces RpcFuture class and futuremethod decorator.

deltachat-rpc-client/src/deltachat_rpc_client/_utils.py

@@ -168,3 +168,33 @@ def parse_system_add_remove(text: str) -> Optional[Tuple[str, str, str]]:
             return "removed", addr, addr
 
     return None
+
+
+class futuremethod:  # noqa: N801
+    """Decorator for async methods."""
+
+    def __init__(self, func):
+        self._func = func
+
+    def __get__(self, instance, owner=None):
+        if instance is None:
+            return self
+
+        def future(*args):
+            generator = self._func(instance, *args)
+            res = next(generator)
+
+            def f():
+                try:
+                    generator.send(res())
+                except StopIteration as e:
+                    return e.value
+
+            return f
+
+        def wrapper(*args):
+            f = future(*args)
+            return f()
+
+        wrapper.future = future
+        return wrapper

deltachat-rpc-client/src/deltachat_rpc_client/account.py

@@ -2,7 +2,7 @@ from dataclasses import dataclass
 from typing import TYPE_CHECKING, List, Optional, Tuple, Union
 from warnings import warn
 
-from ._utils import AttrDict
+from ._utils import AttrDict, futuremethod
 from .chat import Chat
 from .const import ChatlistFlag, ContactFlag, EventType, SpecialContactId
 from .contact import Contact
@@ -76,9 +76,10 @@ class Account:
         """Get self avatar."""
         return self.get_config("selfavatar")
 
-    def configure(self) -> None:
+    @futuremethod
+    def configure(self):
         """Configure an account."""
-        self._rpc.configure(self.id)
+        yield self._rpc.configure.future(self.id)
 
     def create_contact(self, obj: Union[int, str, Contact], name: Optional[str] = None) -> Contact:
         """Create a new Contact or return an existing one.

deltachat-rpc-client/src/deltachat_rpc_client/pytestplugin.py

@@ -5,6 +5,7 @@ from typing import AsyncGenerator, List, Optional
 import pytest
 
 from . import Account, AttrDict, Bot, Client, DeltaChat, EventType, Message
+from ._utils import futuremethod
 from .rpc import Rpc
 
 
@@ -37,9 +38,10 @@ class ACFactory:
         assert not account.is_configured()
         return account
 
-    def new_configured_account(self) -> Account:
+    @futuremethod
+    def new_configured_account(self):
         account = self.new_preconfigured_account()
-        account.configure()
+        yield account.configure.future()
         assert account.is_configured()
         return account
 
@@ -49,8 +51,9 @@ class ACFactory:
         bot.configure(credentials["email"], credentials["password"])
         return bot
 
-    def get_online_account(self) -> Account:
+    @futuremethod
-        account = self.new_configured_account()
+    def get_online_account(self):
+        account = yield self.new_configured_account.future()
         account.start_io()
         while True:
             event = account.wait_for_event()
@@ -59,7 +62,8 @@ class ACFactory:
         return account
 
     def get_online_accounts(self, num: int) -> List[Account]:
-        return [self.get_online_account() for _ in range(num)]
+        futures = [self.get_online_account.future() for _ in range(num)]
+        return [f() for f in futures]
 
     def resetup_account(self, ac: Account) -> Account:
         """Resetup account from scratch, losing the encryption key."""

deltachat-rpc-client/src/deltachat_rpc_client/rpc.py

@@ -13,6 +13,48 @@ class JsonRpcError(Exception):
     pass
 
 
+class RpcFuture:
+    def __init__(self, rpc: "Rpc", request_id: int, event: Event):
+        self.rpc = rpc
+        self.request_id = request_id
+        self.event = event
+
+    def __call__(self):
+        self.event.wait()
+        response = self.rpc.request_results.pop(self.request_id)
+        if "error" in response:
+            raise JsonRpcError(response["error"])
+        if "result" in response:
+            return response["result"]
+        return None
+
+
+class RpcMethod:
+    def __init__(self, rpc: "Rpc", name: str):
+        self.rpc = rpc
+        self.name = name
+
+    def __call__(self, *args) -> Any:
+        """Synchronously calls JSON-RPC method."""
+        future = self.future(*args)
+        return future()
+
+    def future(self, *args) -> Any:
+        """Asynchronously calls JSON-RPC method."""
+        request_id = next(self.rpc.id_iterator)
+        request = {
+            "jsonrpc": "2.0",
+            "method": self.name,
+            "params": args,
+            "id": request_id,
+        }
+        event = Event()
+        self.rpc.request_events[request_id] = event
+        self.rpc.request_queue.put(request)
+
+        return RpcFuture(self.rpc, request_id, event)
+
+
 class Rpc:
     def __init__(self, accounts_dir: Optional[str] = None, **kwargs):
         """The given arguments will be passed to subprocess.Popen()"""
@@ -145,24 +187,4 @@ class Rpc:
         return queue.get()
 
     def __getattr__(self, attr: str):
-        def method(*args) -> Any:
+        return RpcMethod(self, attr)
-            request_id = next(self.id_iterator)
-            request = {
-                "jsonrpc": "2.0",
-                "method": attr,
-                "params": args,
-                "id": request_id,
-            }
-            event = Event()
-            self.request_events[request_id] = event
-            self.request_queue.put(request)
-            event.wait()
-
-            response = self.request_results.pop(request_id)
-            if "error" in response:
-                raise JsonRpcError(response["error"])
-            if "result" in response:
-                return response["result"]
-            return None
-
-        return method