如何在android中实现跨进程锁？

Question

我正在编写一个供多个APP使用的库项目.由于某种原因,我必须为不同的APP做一个函数互斥,所以我需要一个跨进程锁.但据我所知,在android中,APP只能在内部存储中写入自己文件的目录,外部存储不可靠,因为某些设备没有.所以文件锁似乎不适合我,所以有没有其他方法来实现跨进程锁？

谢谢〜

Answer 1

如果你不想(或你不能)使用flock或fcntl,也许你可以使用LocalServerSocket来实现一个自旋锁.例如:

public class SocketLock {
    public SocketLock(String name) {
        mName = name;
    }

    public final synchronized void tryLock() throws IOException {
        if (mServer == null) {
            mServer = new LocalServerSocket(mName);
        } else {
            throw new IllegalStateException("tryLock but has locked");
        }
    }

    public final synchronized boolean timedLock(int ms) {
        long expiredTime = System.currentTimeMillis() + ms;

        while (true) {
            if (System.currentTimeMillis() > expiredTime) {
                return false;
            }
            try {
                try {
                    tryLock();
                    return true;
                } catch (IOException e) {
                    // ignore the exception
                }
                Thread.sleep(10, 0);
            } catch (InterruptedException e) {
                continue;
            }
        }
    }

    public final synchronized void lock() {
        while (true) {
            try {
                try {
                    tryLock();
                    return;
                } catch (IOException e) {
                    // ignore the exception
                }
                Thread.sleep(10, 0);
            } catch (InterruptedException e) {
                continue;
            }
        }
    }

    public final synchronized void release() {
        if (mServer != null) {
            try {
                mServer.close();
            } catch (IOException e) {
                // ignore the exception
            }
        }
    }

    private final String mName;

    private LocalServerSocket mServer;
}