Redis 位图用位而不是存储数字

redis_lab=$(mktemp -d)
curl --fail --location --output "$redis_lab/redis.tar.gz" https://download.redis.io/releases/redis-8.10.1.tar.gz
tar -xzf "$redis_lab/redis.tar.gz" -C "$redis_lab"
make -C "$redis_lab/redis-8.10.1" build redis -j2 MALLOC=libc
export REDIS_SERVER="$redis_lab/redis-8.10.1/src/redis-server"
python3 -m venv "$redis_lab/venv"
"$redis_lab/venv/bin/python" -m pip install redis==8.1.0

from contextlib import contextmanager
import os
from pathlib import Path
import subprocess
from tempfile import TemporaryDirectory
import time

import redis
from redis.backoff import NoBackoff
from redis.retry import Retry


@contextmanager
def instance():
    with TemporaryDirectory(prefix="redis-lab-", dir="/tmp") as directory:
        endpoint = str(Path(directory) / "redis.sock")
        process = subprocess.Popen([
            os.environ["REDIS_SERVER"], "--port", "0",
            "--unixsocket", endpoint, "--unixsocketperm", "700",
            "--save", "", "--appendonly", "no", "--dir", directory,
            "--maxmemory-policy", "noeviction",
        ], stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
        client = redis.Redis(unix_socket_path=endpoint, decode_responses=False,
                             socket_timeout=2, retry=Retry(NoBackoff(), 0))
        try:
            deadline = time.monotonic() + 5
            while True:
                assert process.poll() is None, "Redis exited during startup"
                try:
                    if client.ping():
                        break
                except redis.ConnectionError:
                    if time.monotonic() >= deadline:
                        raise
                    time.sleep(0.02)
            yield client
        finally:
            client.close()
            if process.poll() is None:
                process.terminate()
            try:
                _, errors = process.communicate(timeout=5)
            except subprocess.TimeoutExpired:
                process.kill()
                process.communicate()
                raise
            assert process.returncode == 0, errors.decode()


with instance() as client:
    assert client.getbit("missing", 100) == 0
    assert client.exists("missing") == 0
    assert client.setbit("active", 0, 1) == 0
    assert client.setbit("active", 2, 1) == 0
    assert client.setbit("active", 2, 1) == 1
    assert client.type("active") == b"string"
    assert client.get("active") == b"\xa0"
    assert client.bitcount("active") == 2
    print("offset zero is the high bit; repeated SETBIT returns old 1 without adding membership")

    highest = 8 * 1024 * 1024 - 1
    assert client.setbit("sparse", highest, 0) == 0
    assert client.strlen("sparse") == 1024 * 1024
    assert client.bitcount("sparse") == 0
    assert client.setbit("sparse", highest, 1) == 0
    assert client.setbit("sparse", highest, 0) == 1
    assert client.strlen("sparse") == 1024 * 1024
    print("writing a distant zero allocates 1048576 payload bytes; clearing does not shrink")

    client.set("range", b"\x80\x01")
    assert client.bitcount("range", 0, 1) == 2
    assert client.bitcount("range", 0, 1, mode="BIT") == 1
    assert client.bitpos("range", 1, 1, 1) == 15
    client.set("full", b"\xff")
    assert client.bitpos("full", 0) == 8
    assert client.bitpos("full", 0, 0, 0) == -1
    print("ranges default to bytes; BIT changes units; BITPOS returns absolute bit offsets")

    client.set("other", b"\x50\x01")
    client.set("union", b"obsolete", px=60000)
    assert client.bitop("OR", "union", "active", "other") == 2
    assert client.get("union") == b"\xf0\x01"
    assert client.bitcount("union") == 5
    assert client.ttl("union") == -1
    assert client.bitop("AND", "intersection", "active", "other") == 2
    assert client.get("intersection") == b"\x00\x00"
    print("BITOP zero-pads shorter inputs; OR has 5 flags; destination TTL is removed")

    client.hset("hash", "field", b"value")
    try:
        client.setbit("hash", 0, 1)
    except redis.ResponseError as error:
        assert "WRONGTYPE" in str(error)
    else:
        raise AssertionError("a hash is not converted into a bitmap")
    assert client.hget("hash", "field") == b"value"
    print("bitmap commands reject a hash without converting or replacing it")