feat: add decorators for event handler registration

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

st3/lsp_utils/__init__.py

@@ -1,4 +1,5 @@
 from ._client_handler import ClientHandler
+from ._client_handler import as_notification_handler, as_request_handler
 from .api_wrapper_interface import ApiWrapperInterface
 from .generic_client_handler import GenericClientHandler
 from .npm_client_handler import NpmClientHandler
@@ -14,4 +15,7 @@
     'ServerResourceInterface',
     'ServerStatus'
     'ServerNpmResource',
+    # decorator-related
+    'as_notification_handler',
+    'as_request_handler',
 ]

st3/lsp_utils/_client_handler/__init__.py

@@ -1,3 +1,5 @@
+from .decorator import HANDLER_MARKS
+from .decorator import as_notification_handler, as_request_handler
 from LSP.plugin import __version__ as lsp_version
 
 
@@ -8,4 +10,8 @@
 
 __all__ = [
     'ClientHandler',
+    # decorator-related
+    'HANDLER_MARKS',
+    'as_notification_handler',
+    'as_request_handler',
 ]

st3/lsp_utils/_client_handler/decorator.py

@@ -0,0 +1,39 @@
+from LSP.plugin.core.typing import Any, Callable, Iterable, Union
+
+__all__ = [
+    "as_notification_handler",
+    "as_request_handler",
+]
+
+# the first argument is always "self"
+T_HANDLER = Callable[[Any, Any], None]
+T_SERVER_EVENTS = Union[str, Iterable[str]]
+
+HANDLER_MARKS = {
+    "notification": "__handle_notification_events",
+    "request": "__handle_request_events",
+}
+
+
+def as_notification_handler(server_events: T_SERVER_EVENTS) -> Callable[[T_HANDLER], T_HANDLER]:
+    """ Marks the decorated function as a "notification" event handler. """
+
+    return _as_handler("notification", server_events)
+
+
+def as_request_handler(server_events: T_SERVER_EVENTS) -> Callable[[T_HANDLER], T_HANDLER]:
+    """ Marks the decorated function as a "request" event handler. """
+
+    return _as_handler("request", server_events)
+
+
+def _as_handler(client_event: str, server_events: T_SERVER_EVENTS) -> Callable[[T_HANDLER], T_HANDLER]:
+    """ Marks the decorated function as a event handler. """
+
+    server_events = [server_events] if isinstance(server_events, str) else list(server_events)
+
+    def decorator(func: T_HANDLER) -> T_HANDLER:
+        setattr(func, HANDLER_MARKS[client_event], server_events)
+        return func
+
+    return decorator

st3/lsp_utils/generic_client_handler.py

@@ -1,10 +1,11 @@
-from ._client_handler import ClientHandler
+from ._client_handler import ClientHandler, HANDLER_MARKS
 from .api_wrapper_interface import ApiWrapperInterface
 from .server_resource_interface import ServerResourceInterface
 from abc import ABCMeta
 from LSP.plugin import ClientConfig
 from LSP.plugin import WorkspaceFolder
 from LSP.plugin.core.typing import Dict, List, Optional, Tuple
+import inspect
 import os
 import shutil
 import sublime
@@ -187,4 +188,25 @@ def on_ready(self, api: ApiWrapperInterface) -> None:
 
         :param api: The API instance for interacting with the server.
         """
-        pass
+        self._register_custom_server_event_handlers(api)
+
+    def _register_custom_server_event_handlers(self, api: ApiWrapperInterface) -> None:
+        """
+        Register decorator-style custom event handlers.
+
+        This method works as following steps:
+
+        1. Scan through all methods of this object.
+        2. If a method is decorated, it will has a "handler mark" attribute which is put by the decorator.
+        3. Register the method with wanted events, which are stored in the "handler mark" attribute.
+
+        :param api: The API instance for interacting with the server.
+        """
+        for _, func in inspect.getmembers(self, predicate=inspect.isroutine):
+            # client_event is like "notification", "request"
+            for client_event, handler_mark in HANDLER_MARKS.items():
+                event_registrator = getattr(api, "on_" + client_event, None)
+                if callable(event_registrator):
+                    server_events = getattr(func, handler_mark, [])  # type: List[str]
+                    for server_event in server_events:
+                        event_registrator(server_event, func)