/* Initialize the scripting environment.
* It is possible to call this function to reset the scripting environment
* assuming that we call scriptingRelease() before.
* See scriptingReset() for more information. */
void scriptingInit(void) {
lua_State *lua = lua_open();
luaLoadLibraries(lua);
luaRemoveUnsupportedFunctions(lua);
/* Initialize a dictionary we use to map SHAs to scripts.
* This is useful for replication, as we need to replicate EVALSHA
* as EVAL, so we need to remember the associated script. */
server.lua_scripts = dictCreate(&shaScriptObjectDictType,NULL);
/* Register the redis commands table and fields */
lua_newtable(lua);
/* redis.call */
lua_pushstring(lua,"call");
lua_pushcfunction(lua,luaRedisCallCommand);
lua_settable(lua,-3);
/* redis.pcall */
lua_pushstring(lua,"pcall");
lua_pushcfunction(lua,luaRedisPCallCommand);
lua_settable(lua,-3);
/* redis.log and log levels. */
lua_pushstring(lua,"log");
lua_pushcfunction(lua,luaLogCommand);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_DEBUG");
lua_pushnumber(lua,REDIS_DEBUG);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_VERBOSE");
lua_pushnumber(lua,REDIS_VERBOSE);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_NOTICE");
lua_pushnumber(lua,REDIS_NOTICE);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_WARNING");
lua_pushnumber(lua,REDIS_WARNING);
lua_settable(lua,-3);
/* redis.sha1hex */
lua_pushstring(lua, "sha1hex");
lua_pushcfunction(lua, luaRedisSha1hexCommand);
lua_settable(lua, -3);
/* redis.error_reply and redis.status_reply */
lua_pushstring(lua, "error_reply");
lua_pushcfunction(lua, luaRedisErrorReplyCommand);
lua_settable(lua, -3);
lua_pushstring(lua, "status_reply");
lua_pushcfunction(lua, luaRedisStatusReplyCommand);
lua_settable(lua, -3);
/* Finally set the table as 'redis' global var. */
lua_setglobal(lua,"redis");
/* Replace math.random and math.randomseed with our implementations. */
lua_getglobal(lua,"math");
lua_pushstring(lua,"random");
lua_pushcfunction(lua,redis_math_random);
lua_settable(lua,-3);
lua_pushstring(lua,"randomseed");
lua_pushcfunction(lua,redis_math_randomseed);
lua_settable(lua,-3);
lua_setglobal(lua,"math");
/* Add a helper function that we use to sort the multi bulk output of non
* deterministic commands, when containing 'false' elements. */
{
char *compare_func = "function __redis__compare_helper(a,b)\n"
" if a == false then a = '' end\n"
" if b == false then b = '' end\n"
" return a<b\n"
"end\n";
luaL_loadbuffer(lua,compare_func,strlen(compare_func),"@cmp_func_def");
lua_pcall(lua,0,0,0);
}
/* Add a helper function we use for pcall error reporting.
* Note that when the error is in the C function we want to report the
* information about the caller, that's what makes sense from the point
* of view of the user debugging a script. */
{
char *errh_func = "function __redis__err__handler(err)\n"
" local i = debug.getinfo(2,'nSl')\n"
" if i and i.what == 'C' then\n"
" i = debug.getinfo(3,'nSl')\n"
" end\n"
" if i then\n"
" return i.source .. ':' .. i.currentline .. ': ' .. err\n"
" else\n"
" return err\n"
" end\n"
"end\n";
luaL_loadbuffer(lua,errh_func,strlen(errh_func),"@err_handler_def");
lua_pcall(lua,0,0,0);
}
/* Create the (non connected) client that we use to execute Redis commands
* inside the Lua interpreter.
* Note: there is no need to create it again when this function is called
* by scriptingReset(). */
if (server.lua_client == NULL) {
server.lua_client = createClient(-1);
server.lua_client->flags |= REDIS_LUA_CLIENT;
}
/* Lua beginners ofter don't use "local", this is likely to introduce
* subtle bugs in their code. To prevent problems we protect accesses
* to global variables. */
scriptingEnableGlobalsProtection(lua);
server.lua = lua;
}
/* Initialize the scripting environment.
*
* 初始化脚本环境。
*
* It is possible to call this function to reset the scripting environment
* assuming that we call scriptingRelease() before.
*
* 这个函数也可以在 scriptingRelease() 执行之后使用，用于对脚本环境进行重置。
*
* See scriptingReset() for more information.
*/
void scriptingInit(void)
{
// 创建一个新的 lua 环境
lua_State *lua = lua_open();
// 载入内置函数库
luaLoadLibraries(lua);
// 屏蔽所有不想暴露给脚本环境的函数（目前只有 loadfile）
luaRemoveUnsupportedFunctions(lua);
/* Initialize a dictionary we use to map SHAs to scripts.
* 创建一个字典，用于将 SHA 校验码映射到脚本
* This is useful for replication, as we need to replicate EVALSHA
* as EVAL, so we need to remember the associated script.
* 因为 Redis 目前复制脚本的方法是将 EVALSHA 转换成 EVAL 来进行的，
* 所以程序需要保存和 SHA 校验值相对应的脚本。
*/
server.lua_scripts = dictCreate(&shaScriptObjectDictType,NULL);
/* Register the redis commands table and fields */
// 创建 table ，并以给定名称将 C 函数注册到表格上
lua_newtable(lua);
/* 注册 redis.call */
lua_pushstring(lua,"call");
lua_pushcfunction(lua,luaRedisCallCommand);
lua_settable(lua,-3);
/* 注册 redis.pcall */
lua_pushstring(lua,"pcall");
lua_pushcfunction(lua,luaRedisPCallCommand);
lua_settable(lua,-3);
/* 注册 redis.log 和 log levels. */
lua_pushstring(lua,"log");
lua_pushcfunction(lua,luaLogCommand);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_DEBUG");
lua_pushnumber(lua,REDIS_DEBUG);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_VERBOSE");
lua_pushnumber(lua,REDIS_VERBOSE);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_NOTICE");
lua_pushnumber(lua,REDIS_NOTICE);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_WARNING");
lua_pushnumber(lua,REDIS_WARNING);
lua_settable(lua,-3);
/* 注册 redis.sha1hex */
lua_pushstring(lua, "sha1hex");
lua_pushcfunction(lua, luaRedisSha1hexCommand);
lua_settable(lua, -3);
/* 注册 redis.error_reply and redis.status_reply */
lua_pushstring(lua, "error_reply");
lua_pushcfunction(lua, luaRedisErrorReplyCommand);
lua_settable(lua, -3);
lua_pushstring(lua, "status_reply");
lua_pushcfunction(lua, luaRedisStatusReplyCommand);
lua_settable(lua, -3);
/* Finally set the table as 'redis' global var. */
// 将 table 设置为 redis 全局变量
lua_setglobal(lua,"redis");
/* Replace math.random and math.randomseed with our implementations. */
// 将 math.random 和 math.randomseed 设置为 Redis 实现
// 用于生成确定性的随机数
// （对于同一个 seed ，生成的随机序列总是相同）
lua_getglobal(lua,"math");
lua_pushstring(lua,"random");
lua_pushcfunction(lua,redis_math_random);
lua_settable(lua,-3);
lua_pushstring(lua,"randomseed");
lua_pushcfunction(lua,redis_math_randomseed);
lua_settable(lua,-3);
lua_setglobal(lua,"math");
/* Add a helper funciton that we use to sort the multi bulk output of non
* deterministic commands, when containing 'false' elements.
* 用于对不确定性多个回复的输出进行排序
*/
{
char *compare_func = "function __redis__compare_helper(a,b)\n"
" if a == false then a = '' end\n"
" if b == false then b = '' end\n"
" return a<b\n"
"end\n";
luaL_loadbuffer(lua,compare_func,strlen(compare_func),"@cmp_func_def");
lua_pcall(lua,0,0,0);
}
/* Create the (non connected) client that we use to execute Redis commands
* inside the Lua interpreter.
* 创建一个无网络连接的伪客户端，用于执行 Lua 脚本中的命令
* Note: there is no need to create it again when this function is called
* by scriptingReset().
*/
if (server.lua_client == NULL)
{
server.lua_client = createClient(-1);
server.lua_client->flags |= REDIS_LUA_CLIENT;
}
/* Lua beginners ofter don't use "local", this is likely to introduce
* subtle bugs in their code. To prevent problems we protect accesses
* to global variables.
*
* 为了避免全局变量被意外地修改，保护全局变量。
*/
scriptingEnableGlobalsProtection(lua);
// 将 lua 环境赋值到服务器变量
server.lua = lua;
}
