Use a dedicated thread for ctrl key state polling

The dedicated thread is more reliable than using ST's async thread
because we are not at the risk of getting delayed by another task
running on it and since we need to respond to user input in a timely
manner to update the UI, our polling is timing-critical.

Closes #2

Author: FichteFoll

plugin/ctrl_release/linux.py

@@ -3,6 +3,7 @@
 import ctypes
 import ctypes.util
 import os
+import threading
 from collections.abc import Callable
 from dataclasses import dataclass
 from typing import Any
@@ -24,45 +25,41 @@ class _X11State:
     xquery_keymap: Callable[[int, Any], int]
 
 
-class CtrlReleasePoller:
+class CtrlReleasePoller(threading.Thread):
     def __init__(self, on_release, interval_ms):
+        super().__init__(daemon=True)
         self._on_release = on_release
         self._interval_ms = interval_ms
-        self._active = False
         self._state = self._open_x11_state()
+        self._stop_event = threading.Event()
 
     def start(self) -> None:
-        if self._active:
+        if self.is_alive():
             return
-        self._active = True
-        self._schedule()
+        self._stop_event.clear()
+        super().start()
 
     def stop(self) -> None:
-        self._active = False
+        self._stop_event.set()
+
+    def run(self) -> None:
+        try:
+            while not self._stop_event.wait(self._interval_ms / 1000):
+                if self._state is None or not self._ctrl_down():
+                    self._fire_release()
+                    break
+        finally:
+            self._close_state()
+
+    def _close_state(self) -> None:
         if self._state is not None:
             self._state.xclose_display(self._state.display)
             self._state = None
 
-    def _schedule(self) -> None:
-        if not self._active:
-            return
-        sublime.set_timeout_async(self._poll, self._interval_ms)
-
-    def _poll(self) -> None:
-        if not self._active:
-            return
-        if self._state is None:
-            self._fire_release()
-            return
-        if not self._ctrl_down():
-            self._fire_release()
-            return
-        self._schedule()
-
     def _fire_release(self) -> None:
-        if not self._active:
+        if self._stop_event.is_set():
             return
-        self._active = False
+        self._stop_event.set()
         sublime.set_timeout(self._on_release)
 
     def _ctrl_down(self) -> bool:

plugin/ctrl_release/macos.py

@@ -2,6 +2,7 @@
 
 import ctypes
 import ctypes.util
+import threading
 from collections.abc import Callable
 from typing import Any
 
@@ -14,39 +15,33 @@
 _CORE_GRAPHICS: Any | None = None
 
 
-class CtrlReleasePoller:
+class CtrlReleasePoller(threading.Thread):
     def __init__(self, on_release: Callable[[], None], interval_ms: int) -> None:
+        super().__init__(daemon=True)
         self._on_release = on_release
         self._interval_ms = interval_ms
-        self._active = False
         self._core_graphics = _get_core_graphics()
+        self._stop_event = threading.Event()
 
     def start(self) -> None:
-        if self._active:
+        if self.is_alive():
             return
-        self._active = True
-        self._schedule()
+        self._stop_event.clear()
+        super().start()
 
     def stop(self) -> None:
-        self._active = False
+        self._stop_event.set()
 
-    def _schedule(self) -> None:
-        if not self._active:
-            return
-        sublime.set_timeout_async(self._poll, self._interval_ms)
-
-    def _poll(self) -> None:
-        if not self._active:
-            return
-        if self._core_graphics is None or not self._ctrl_down():
-            self._fire_release()
-            return
-        self._schedule()
+    def run(self) -> None:
+        while not self._stop_event.wait(self._interval_ms / 1000):
+            if self._core_graphics is None or not self._ctrl_down():
+                self._fire_release()
+                break
 
     def _fire_release(self) -> None:
-        if not self._active:
+        if self._stop_event.is_set():
             return
-        self._active = False
+        self._stop_event.set()
         sublime.set_timeout(self._on_release)
 
     def _ctrl_down(self) -> bool:

plugin/ctrl_release/windows.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import ctypes
+import threading
 from collections.abc import Callable
 from typing import Any
 
@@ -11,39 +12,33 @@
 _USER32: Any | None = None
 
 
-class CtrlReleasePoller:
+class CtrlReleasePoller(threading.Thread):
     def __init__(self, on_release: Callable[[], None], interval_ms: int) -> None:
+        super().__init__(daemon=True)
         self._on_release = on_release
         self._interval_ms = interval_ms
-        self._active = False
         self._user32: Any = _get_user32()
+        self._stop_event = threading.Event()
 
     def start(self) -> None:
-        if self._active:
+        if self.is_alive():
             return
-        self._active = True
-        self._schedule()
+        self._stop_event.clear()
+        super().start()
 
     def stop(self) -> None:
-        self._active = False
+        self._stop_event.set()
 
-    def _schedule(self) -> None:
-        if not self._active:
-            return
-        sublime.set_timeout_async(self._poll, self._interval_ms)
-
-    def _poll(self) -> None:
-        if not self._active:
-            return
-        if self._user32 is None or not self._ctrl_down():
-            self._fire_release()
-            return
-        self._schedule()
+    def run(self) -> None:
+        while not self._stop_event.wait(self._interval_ms / 1000):
+            if self._user32 is None or not self._ctrl_down():
+                self._fire_release()
+                break
 
     def _fire_release(self) -> None:
-        if not self._active:
+        if self._stop_event.is_set():
             return
-        self._active = False
+        self._stop_event.set()
         sublime.set_timeout(self._on_release)
 
     def _ctrl_down(self) -> bool:

plugin/history.py

@@ -119,7 +119,7 @@ def sync_selection_history(
         for group_key, group_state_stack in list(groups.items()):
             try:
                 group = int(group_key)
-            except (TypeError, ValueError):
+            except TypeError, ValueError:
                 # Unexpected/corrupt key; drop it to avoid crashing.
                 del groups[group_key]
                 changed = True