Function luaRedisGenericCommand

app/redis-6.2.6/src/scripting.c:503–847

#define LUA_CMD_OBJCACHE_SIZE 32
#define LUA_CMD_OBJCACHE_MAX_LEN 64
int luaRedisGenericCommand(lua_State *lua, int raise_error) {
    int j, argc = lua_gettop(lua);
    struct redisCommand *cmd;
    client *c = server.lua_client;
    sds reply;

    /* Cached across calls. */
    static robj **argv = NULL;
    static int argv_size = 0;
    static robj *cached_objects[LUA_CMD_OBJCACHE_SIZE];
    static size_t cached_objects_len[LUA_CMD_OBJCACHE_SIZE];
    static int inuse = 0;   /* Recursive calls detection. */

    /* By using Lua debug hooks it is possible to trigger a recursive call
     * to luaRedisGenericCommand(), which normally should never happen.
     * To make this function reentrant is futile and makes it slower, but
     * we should at least detect such a misuse, and abort. */
    if (inuse) {
        char *recursion_warning =
            "luaRedisGenericCommand() recursive call detected. "
            "Are you doing funny stuff with Lua debug hooks?";
        serverLog(LL_WARNING,"%s",recursion_warning);
        luaPushError(lua,recursion_warning);
        return 1;
    }
    inuse++;

    /* Require at least one argument */
    if (argc == 0) {
        luaPushError(lua,
            "Please specify at least one argument for redis.call()");
        inuse--;
        return raise_error ? luaRaiseError(lua) : 1;
    }

    /* Build the arguments vector */
    if (argv_size < argc) {
        argv = zrealloc(argv,sizeof(robj*)*argc);
        argv_size = argc;
    }

    for (j = 0; j < argc; j++) {
        char *obj_s;
        size_t obj_len;
        char dbuf[64];

        if (lua_type(lua,j+1) == LUA_TNUMBER) {
            /* We can't use lua_tolstring() for number -> string conversion
             * since Lua uses a format specifier that loses precision. */
            lua_Number num = lua_tonumber(lua,j+1);

            obj_len = snprintf(dbuf,sizeof(dbuf),"%.17g",(double)num);
            obj_s = dbuf;
        } else {
            obj_s = (char*)lua_tolstring(lua,j+1,&obj_len);
            if (obj_s == NULL) break; /* Not a string. */
        }