Function stream_trim

app/redis-6.2.6/tests/modules/stream.c:176–233

* STREAM.TRIM key (MAXLEN (=|~) length | MINID (=|~) id) */

 * STREAM.TRIM key (MAXLEN (=|~) length | MINID (=|~) id)
 */
int stream_trim(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
    if (argc != 5) {
        RedisModule_WrongArity(ctx);
        return REDISMODULE_OK;
    }

    /* Parse args */
    int trim_by_id = 0; /* 0 = maxlen, 1 = minid */
    long long maxlen;
    RedisModuleStreamID minid;
    size_t arg_len;
    const char *arg = RedisModule_StringPtrLen(argv[2], &arg_len);
    if (!strcasecmp(arg, "minid")) {
        trim_by_id = 1;
        if (RedisModule_StringToStreamID(argv[4], &minid) != REDISMODULE_OK) {
            RedisModule_ReplyWithError(ctx, "ERR Invalid stream ID");
            return REDISMODULE_OK;
        }
    } else if (!strcasecmp(arg, "maxlen")) {
        if (RedisModule_StringToLongLong(argv[4], &maxlen) == REDISMODULE_ERR) {
            RedisModule_ReplyWithError(ctx, "ERR Maxlen must be a number");
            return REDISMODULE_OK;
        }
    } else {
        RedisModule_ReplyWithError(ctx, "ERR Invalid arguments");
        return REDISMODULE_OK;
    }

    /* Approx or exact */
    int flags;
    arg = RedisModule_StringPtrLen(argv[3], &arg_len);
    if (arg_len == 1 && arg[0] == '~') {
        flags = REDISMODULE_STREAM_TRIM_APPROX;
    } else if (arg_len == 1 && arg[0] == '=') {
        flags = 0;
    } else {
        RedisModule_ReplyWithError(ctx, "ERR Invalid approx-or-exact mark");
        return REDISMODULE_OK;
    }

    /* Trim */
    RedisModuleKey *key = RedisModule_OpenKey(ctx, argv[1], REDISMODULE_WRITE);
    long long trimmed;
    if (trim_by_id) {
        trimmed = RedisModule_StreamTrimByID(key, flags, &minid);
    } else {
        trimmed = RedisModule_StreamTrimByLength(key, flags, maxlen);
    }

    /* Return result */
    if (trimmed < 0) {
        RedisModule_ReplyWithError(ctx, "ERR Trimming failed");
    } else {
        RedisModule_ReplyWithLongLong(ctx, trimmed);
    }
    RedisModule_CloseKey(key);
    return REDISMODULE_OK;
}