sanic/sanic/application/spinner.py

81 lines
2.2 KiB
Python

import os
import sys
import time
from contextlib import contextmanager
from queue import Queue
from threading import Thread
if os.name == "nt": # noqa
import ctypes # noqa
class _CursorInfo(ctypes.Structure):
_fields_ = [("size", ctypes.c_int), ("visible", ctypes.c_byte)]
class Spinner: # noqa
"""Spinner class to show a loading spinner in the terminal.
Used internally by the `loading` context manager.
"""
def __init__(self, message: str) -> None:
self.message = message
self.queue: Queue[int] = Queue()
self.spinner = self.cursor()
self.thread = Thread(target=self.run)
def start(self):
self.queue.put(1)
self.thread.start()
self.hide()
def run(self):
while self.queue.get():
output = f"\r{self.message} [{next(self.spinner)}]"
sys.stdout.write(output)
sys.stdout.flush()
time.sleep(0.1)
self.queue.put(1)
def stop(self):
self.queue.put(0)
self.thread.join()
self.show()
@staticmethod
def cursor():
while True:
yield from "|/-\\"
@staticmethod
def hide():
if os.name == "nt":
ci = _CursorInfo()
handle = ctypes.windll.kernel32.GetStdHandle(-11)
ctypes.windll.kernel32.GetConsoleCursorInfo(handle, ctypes.byref(ci))
ci.visible = False
ctypes.windll.kernel32.SetConsoleCursorInfo(handle, ctypes.byref(ci))
elif os.name == "posix":
sys.stdout.write("\033[?25l")
sys.stdout.flush()
@staticmethod
def show():
if os.name == "nt":
ci = _CursorInfo()
handle = ctypes.windll.kernel32.GetStdHandle(-11)
ctypes.windll.kernel32.GetConsoleCursorInfo(handle, ctypes.byref(ci))
ci.visible = True
ctypes.windll.kernel32.SetConsoleCursorInfo(handle, ctypes.byref(ci))
elif os.name == "posix":
sys.stdout.write("\033[?25h")
sys.stdout.flush()
@contextmanager
def loading(message: str = "Loading"): # noqa
spinner = Spinner(message)
spinner.start()
yield
spinner.stop()