GH-130328: pasting in new REPL is slow on Windows

Lib/_pyrepl/windows_console.py

@@ -22,8 +22,6 @@
 import io
 import os
 import sys
-import time
-import msvcrt
 
 import ctypes
 from ctypes.wintypes import (
@@ -44,14 +42,17 @@
 from .windows_eventqueue import EventQueue
 
 try:
- from ctypes import GetLastError, WinDLL, windll, WinError # type: ignore[attr-defined]
+ from ctypes import get_last_error, GetLastError, WinDLL, windll, WinError # type: ignore[attr-defined]
 except:
  # Keep MyPy happy off Windows
  from ctypes import CDLL as WinDLL, cdll as windll
 
  def GetLastError() -> int:
  return 42
 
+ def get_last_error() -> int:
+ return 42
+
  class WinError(OSError): # type: ignore[no-redef]
  def __init__(self, err: int | None, descr: str | None = None) -> None:
  self.err = err
@@ -108,6 +109,12 @@ def __init__(self, err: int | None, descr: str | None = None) -> None:
 ALT_ACTIVE = 0x01 | 0x02
 CTRL_ACTIVE = 0x04 | 0x08
 
+WAIT_TIMEOUT = 0x102
+WAIT_FAILED = 0xFFFFFFFF
+
+# from winbase.h
+INFINITE = 0xFFFFFFFF
+
 
 class _error(Exception):
  pass
@@ -409,12 +416,8 @@ def _getscrollbacksize(self) -> int:
  return info.srWindow.Bottom # type: ignore[no-any-return]
 
  def _read_input(self, block: bool = True) -> INPUT_RECORD | None:
- if not block:
- events = DWORD()
- if not GetNumberOfConsoleInputEvents(InHandle, events):
- raise WinError(GetLastError())
- if not events.value:
- return None
+ if not block and not self.wait(timeout=0):
+ return None
 
  rec = INPUT_RECORD()
  read = DWORD()
@@ -522,14 +525,16 @@ def getpending(self) -> Event:
 
  def wait(self, timeout: float | None) -> bool:
  """Wait for an event."""
- # Poor man's Windows select loop
- start_time = time.time()
- while True:
- if msvcrt.kbhit(): # type: ignore[attr-defined]
- return True
- if timeout and time.time() - start_time > timeout / 1000:
- return False
- time.sleep(0.01)
+ if timeout is None:
+ timeout = INFINITE
+ else:
+ timeout = int(timeout)
+ ret = WaitForSingleObject(InHandle, timeout)
+ if ret == WAIT_FAILED:
+ raise WinError(get_last_error())
+ elif ret == WAIT_TIMEOUT:
+ return False
+ return True
 
  def repaint(self) -> None:
  raise NotImplementedError("No repaint support")
@@ -649,14 +654,15 @@ class INPUT_RECORD(Structure):
  ReadConsoleInput.argtypes = [HANDLE, POINTER(INPUT_RECORD), DWORD, POINTER(DWORD)]
  ReadConsoleInput.restype = BOOL
 
- GetNumberOfConsoleInputEvents = _KERNEL32.GetNumberOfConsoleInputEvents
- GetNumberOfConsoleInputEvents.argtypes = [HANDLE, POINTER(DWORD)]
- GetNumberOfConsoleInputEvents.restype = BOOL
 
  FlushConsoleInputBuffer = _KERNEL32.FlushConsoleInputBuffer
  FlushConsoleInputBuffer.argtypes = [HANDLE]
  FlushConsoleInputBuffer.restype = BOOL
 
+ WaitForSingleObject = _KERNEL32.WaitForSingleObject
+ WaitForSingleObject.argtypes = [HANDLE, DWORD]
+ WaitForSingleObject.restype = DWORD
+
  OutHandle = GetStdHandle(STD_OUTPUT_HANDLE)
  InHandle = GetStdHandle(STD_INPUT_HANDLE)
 else:
@@ -670,7 +676,7 @@ def _win_only(*args, **kwargs):
  GetConsoleMode = _win_only
  SetConsoleMode = _win_only
  ReadConsoleInput = _win_only
- GetNumberOfConsoleInputEvents = _win_only
  FlushConsoleInputBuffer = _win_only
+ WaitForSingleObject = _win_only
  OutHandle = 0
  InHandle = 0

Misc/NEWS.d/next/Library/2025-04-24-18-07-49.gh-issue-130328.z7CN8z.rst

@@ -0,0 +1 @@
+Speedup pasting in ``PyREPL`` on Windows. Fix by Chris Eibl.