Python模拟一个多线程加锁的过程

多线程PC过程模拟

注意点：
1）首先通过信号量来判断是否运行该段程序。如果信号量是0，则阻塞一下。否则，把信号量p一下。
2）完成任务后，把信号量v一下。
3）记住先p后v的口诀。

import threading
import numpy as np

class Product_Consume():
    def __init__(self):
        self.write_signal = 1
        self.read_signal = 0
        self.buffer = 0

    def _p_write(self):
        while True:
            if self.write_signal > 0:
                self.write_signal -= 1
                break

    def _p_read(self):
        while True:
            if self.read_signal > 0:
                self.read_signal -= 1
                break

    def _v_write(self):
        self.write_signal += 1

    def _v_read(self):
        self.read_signal += 1

    def write(self):
        while True:
            print('---Task Begin---')
            num = np.random.random()
            self._p_write()
            self.buffer = num
            print("Writing A := ", self.buffer)
            self._v_read()

    def read(self):
        while True:
            self._p_read()
            print("Reading A := ", self.buffer)
            self._v_write()
            print('---Task End---')

    def __call__(self):
        read_thread = threading.Thread(target=self.read)
        write_thread = threading.Thread(target=self.write)
        read_thread.start()
        write_thread.start()


pc = Product_Consume()
pc()