void decrbyCommand(redisClient *c) {
long long incr;
if (getLongLongFromObjectOrReply(c, c->argv[2], &incr, NULL) != REDIS_OK)
return;
incrDecrCommand(c,-incr);
}
void setGenericCommand(redisClient *c, int flags, robj *key, robj *val, robj *expire, int unit, robj *ok_reply, robj *abort_reply) {
long long milliseconds = 0; /* initialized to avoid any harmness warning */
if (expire) {
if (getLongLongFromObjectOrReply(c, expire, &milliseconds, NULL) != REDIS_OK)
return;
if (milliseconds <= 0) {
addReplyErrorFormat(c,"invalid expire time in %s",c->cmd->name);
return;
}
if (unit == UNIT_SECONDS) milliseconds *= 1000;
}
if ((flags & REDIS_SET_NX && lookupKeyWrite(c->db,key) != NULL) ||
(flags & REDIS_SET_XX && lookupKeyWrite(c->db,key) == NULL))
{
addReply(c, abort_reply ? abort_reply : shared.nullbulk);
return;
}
setKey(c->db,key,val);
server.dirty++;
if (expire) setExpire(c->db,key,mstime()+milliseconds);
notifyKeyspaceEvent(REDIS_NOTIFY_STRING,"set",key,c->db->id);
if (expire) notifyKeyspaceEvent(REDIS_NOTIFY_GENERIC,
"expire",key,c->db->id);
addReply(c, ok_reply ? ok_reply : shared.ok);
}
void incrDecrCommand(redisClient *c, long long incr) {
long long value;
robj *o;
#ifdef AUTH_FEATURE
/* Check mod permissions */
if (authCheckModOrReply(c) == REDIS_ERR)
return;
/* Check path permissions */
if (authCheckPathOrReply(c, c->argv[1]) == REDIS_ERR ||
authCheckPathOrReply(c, c->argv[2]) == REDIS_ERR)
return;
#endif
o = lookupKeyWrite(c->db,c->argv[1]);
if (o != NULL && checkType(c,o,REDIS_STRING)) return;
if (getLongLongFromObjectOrReply(c,o,&value,NULL) != REDIS_OK) return;
value += incr;
o = createStringObjectFromLongLong(value);
dbReplace(c->db,c->argv[1],o);
touchWatchedKey(c->db,c->argv[1]);
server.dirty++;
addReply(c,shared.colon);
addReply(c,o);
addReply(c,shared.crlf);
}
void getrangeCommand(client *c) {
robj *o;
long long start, end;
char *str, llbuf[32];
size_t strlen;
if (getLongLongFromObjectOrReply(c,c->argv[2],&start,NULL) != C_OK)
return;
if (getLongLongFromObjectOrReply(c,c->argv[3],&end,NULL) != C_OK)
return;
if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptybulk)) == NULL ||
checkType(c,o,OBJ_STRING)) return;
if (o->encoding == OBJ_ENCODING_INT) {
str = llbuf;
strlen = ll2string(llbuf,sizeof(llbuf),(long)o->ptr);
} else {
str = o->ptr;
strlen = sdslen(str);
}
/* Convert negative indexes */
if (start < 0 && end < 0 && start > end) {
addReply(c,shared.emptybulk);
return;
}
if (start < 0) start = strlen+start;
if (end < 0) end = strlen+end;
if (start < 0) start = 0;
if (end < 0) end = 0;
if ((unsigned long long)end >= strlen) end = strlen-1;
/* Precondition: end >= 0 && end < strlen, so the only condition where
* nothing can be returned is: start > end. */
if (start > end || strlen == 0) {
addReply(c,shared.emptybulk);
} else {
addReplyBulkCBuffer(c,(char*)str+start,end-start+1);
}
}
int getLongFromObjectOrReply(rr_client_t *c, robj *o, long *target, const char *msg) {
long long value;
if (getLongLongFromObjectOrReply(c, o, &value, msg) != RR_OK) return RR_ERROR;
if (value < LONG_MIN || value > LONG_MAX) {
if (msg != NULL) {
reply_add_err(c,(char*)msg);
} else {
reply_add_err(c,"value is out of range");
}
return RR_ERROR;
}
*target = value;
return RR_OK;
}
int getLongFromObjectOrReply(client *c, robj *o, long *target, const char *msg) {
long long value;
if (getLongLongFromObjectOrReply(c, o, &value, msg) != C_OK) return C_ERR;
if (value < LONG_MIN || value > LONG_MAX) {
if (msg != NULL) {
addReplyError(c,(char*)msg);
} else {
addReplyError(c,"value is out of range");
}
return C_ERR;
}
*target = value;
return C_OK;
}
//从对象中将字符串值转换为long并存储在target中，若失败，失败发送信息给client
int getLongFromObjectOrReply(client *c, robj *o, long *target, const char *msg) {
long long value;
//如果将字符串值转换为long long出错，发送错误信息msg，返回-1，否则保存整数值到value中
if (getLongLongFromObjectOrReply(c, o, &value, msg) != C_OK) return C_ERR;
if (value < LONG_MIN || value > LONG_MAX) { //如果long long类型的value超出long所能表示的范围
if (msg != NULL) { //msg不为空
addReplyError(c,(char*)msg); //发送指定的msg给client
} else {
addReplyError(c,"value is out of range"); //发送普通字符串
}
return C_ERR;
}
*target = value; //否则将long大小的value返回到传入参数
return C_OK;
}
void incrDecrCommand(redisClient *c, long long incr) {
long long value;
robj *o;
o = lookupKeyWrite(c->db,c->argv[1]);
if (o != NULL && checkType(c,o,REDIS_STRING)) return;
if (getLongLongFromObjectOrReply(c,o,&value,NULL) != REDIS_OK) return;
value += incr;
o = createStringObjectFromLongLong(value);
dbReplace(c->db,c->argv[1],o);
server.dirty++;
addReply(c,shared.colon);
addReply(c,o);
addReply(c,shared.crlf);
}
int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
long long value;
if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
if (value < LONG_MIN || value > LONG_MAX) {
if (msg != NULL) {
addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
} else {
addReplySds(c, sdsnew("-ERR value is out of range\r\n"));
}
return REDIS_ERR;
}
*target = value;
return REDIS_OK;
}
/* This is the generic command implementation for EXPIRE, PEXPIRE, EXPIREAT
* and PEXPIREAT. Because the commad second argument may be relative or absolute
* the "basetime" argument is used to signal what the base time is (either 0
* for *AT variants of the command, or the current time for relative expires).
*
* unit is either UNIT_SECONDS or UNIT_MILLISECONDS, and is only used for
* the argv[2] parameter. The basetime is always specified in milliseconds. */
void expireGenericCommand(client *c, long long basetime, int unit) {
robj *key = c->argv[1], *param = c->argv[2];
long long when; /* unix time in milliseconds when the key will expire. */
if (getLongLongFromObjectOrReply(c, param, &when, NULL) != C_OK)
return;
if (unit == UNIT_SECONDS) when *= 1000;
when += basetime;
/* No key, return zero. */
if (lookupKeyWrite(c->db,key) == NULL) {
addReply(c,shared.czero);
return;
}
/* EXPIRE with negative TTL, or EXPIREAT with a timestamp into the past
* should never be executed as a DEL when load the AOF or in the context
* of a slave instance.
*
* Instead we take the other branch of the IF statement setting an expire
* (possibly in the past) and wait for an explicit DEL from the master. */
if (when <= mstime() && !server.loading && !server.masterhost) {
robj *aux;
serverAssertWithInfo(c,key,dbDelete(c->db,key));
server.dirty++;
/* Replicate/AOF this as an explicit DEL. */
aux = createStringObject("DEL",3);
rewriteClientCommandVector(c,2,aux,key);
decrRefCount(aux);
signalModifiedKey(c->db,key);
notifyKeyspaceEvent(NOTIFY_GENERIC,"del",key,c->db->id);
addReply(c, shared.cone);
return;
} else {
setExpire(c->db,key,when);
addReply(c,shared.cone);
signalModifiedKey(c->db,key);
notifyKeyspaceEvent(NOTIFY_GENERIC,"expire",key,c->db->id);
server.dirty++;
return;
}
}
int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
long long value;
// 先尝试以 long long 类型取出值
if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
// 然后检查值是否在 long 类型的范围之内
if (value < LONG_MIN || value > LONG_MAX) {
if (msg != NULL) {
addReplyError(c,(char*)msg);
} else {
addReplyError(c,"value is out of range");
}
return REDIS_ERR;
}
*target = value;
return REDIS_OK;
}
void
migpexpireatCommand (client * c)
{
dictEntry *de;
robj *key = c->argv[1], *param = c->argv[2];
long long when;
if (getLongLongFromObjectOrReply (c, param, &when, NULL) != C_OK)
return;
de = dictFind (c->db->dict, key->ptr);
if (de == NULL)
{
addReply (c, shared.czero);
return;
}
setExpire (c->db, key, when);
addReply (c, shared.cone);
signalModifiedKey (c->db, key);
server.dirty++;
}
/* Get a timeout value from an object and store it into 'timeout'.
* The final timeout is always stored as milliseconds as a time where the
* timeout will expire, however the parsing is performed according to
* the 'unit' that can be seconds or milliseconds.
*
* Note that if the timeout is zero (usually from the point of view of
* commands API this means no timeout) the value stored into 'timeout'
* is zero. */
int getTimeoutFromObjectOrReply(client *c, robj *object, mstime_t *timeout, int unit) {
long long tval;
if (getLongLongFromObjectOrReply(c,object,&tval,
"timeout is not an integer or out of range") != C_OK)
return C_ERR;
if (tval < 0) {
addReplyError(c,"timeout is negative");
return C_ERR;
}
if (tval > 0) {
if (unit == UNIT_SECONDS) tval *= 1000;
tval += mstime();
}
*timeout = tval;
return C_OK;
}
void incrDecrCommand(redisClient *c, long long incr) {
long long value, oldvalue;
robj *o, *new;
o = lookupKeyWrite(c->db,c->argv[1]);
if (o != NULL && checkType(c,o,REDIS_STRING)) return;
if (getLongLongFromObjectOrReply(c,o,&value,NULL) != REDIS_OK) return;
oldvalue = value;
if ((incr < 0 && oldvalue < 0 && incr < (LLONG_MIN-oldvalue)) ||
(incr > 0 && oldvalue > 0 && incr > (LLONG_MAX-oldvalue))) {
addReplyError(c,"increment or decrement would overflow");
return;
}
value += incr;
if (o && o->refcount == 1 && o->encoding == REDIS_ENCODING_INT &&
(value < 0 || value >= REDIS_SHARED_INTEGERS) &&
value >= LONG_MIN && value <= LONG_MAX)
{
new = o;
o->ptr = (void*)((long)value);
} else {
void evalGenericCommand(redisClient *c, int evalsha) {
lua_State *lua = server.lua;
char funcname[43];
long long numkeys;
int delhook = 0, err;
/* We want the same PRNG sequence at every call so that our PRNG is
* not affected by external state. */
redisSrand48(0);
/* We set this flag to zero to remember that so far no random command
* was called. This way we can allow the user to call commands like
* SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
* is called (otherwise the replication and AOF would end with non
* deterministic sequences).
*
* Thanks to this flag we'll raise an error every time a write command
* is called after a random command was used. */
server.lua_random_dirty = 0;
server.lua_write_dirty = 0;
/* Get the number of arguments that are keys */
if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
return;
if (numkeys > (c->argc - 3)) {
addReplyError(c,"Number of keys can't be greater than number of args");
return;
}
/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
funcname[0] = 'f';
funcname[1] = '_';
if (!evalsha) {
/* Hash the code if this is an EVAL call */
sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
} else {
/* We already have the SHA if it is a EVALSHA */
int j;
char *sha = c->argv[1]->ptr;
for (j = 0; j < 40; j++)
funcname[j+2] = tolower(sha[j]);
funcname[42] = '\0';
}
/* Push the pcall error handler function on the stack. */
lua_getglobal(lua, "__redis__err__handler");
/* Try to lookup the Lua function */
lua_getglobal(lua, funcname);
if (lua_isnil(lua,-1)) {
lua_pop(lua,1); /* remove the nil from the stack */
/* Function not defined... let's define it if we have the
* body of the function. If this is an EVALSHA call we can just
* return an error. */
if (evalsha) {
lua_pop(lua,1); /* remove the error handler from the stack. */
addReply(c, shared.noscripterr);
return;
}
if (luaCreateFunction(c,lua,funcname,c->argv[1]) == REDIS_ERR) {
lua_pop(lua,1); /* remove the error handler from the stack. */
/* The error is sent to the client by luaCreateFunction()
* itself when it returns REDIS_ERR. */
return;
}
/* Now the following is guaranteed to return non nil */
lua_getglobal(lua, funcname);
redisAssert(!lua_isnil(lua,-1));
}
/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
/* Select the right DB in the context of the Lua client */
selectDb(server.lua_client,c->db->id);
/* Set a hook in order to be able to stop the script execution if it
* is running for too much time.
* We set the hook only if the time limit is enabled as the hook will
* make the Lua script execution slower. */
server.lua_caller = c;
server.lua_time_start = mstime();
server.lua_kill = 0;
if (server.lua_time_limit > 0 && server.masterhost == NULL) {
lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
delhook = 1;
}
/* At this point whether this script was never seen before or if it was
* already defined, we can call it. We have zero arguments and expect
* a single return value. */
err = lua_pcall(lua,0,1,-2);
/* Perform some cleanup that we need to do both on error and success. */
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
if (server.lua_timedout) {
server.lua_timedout = 0;
/* Restore the readable handler that was unregistered when the
* script timeout was detected. */
aeCreateFileEvent(server.el,c->fd,AE_READABLE,
readQueryFromClient,c);
}
server.lua_caller = NULL;
selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
lua_gc(lua,LUA_GCSTEP,1);
if (err) {
addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
funcname, lua_tostring(lua,-1));
lua_pop(lua,2); /* Consume the Lua reply and remove error handler. */
} else {
/* On success convert the Lua return value into Redis protocol, and
* send it to * the client. */
luaReplyToRedisReply(c,lua); /* Convert and consume the reply. */
lua_pop(lua,1); /* Remove the error handler. */
}
/* EVALSHA should be propagated to Slave and AOF file as full EVAL, unless
* we are sure that the script was already in the context of all the
* attached slaves *and* the current AOF file if enabled.
*
* To do so we use a cache of SHA1s of scripts that we already propagated
* as full EVAL, that's called the Replication Script Cache.
*
* For repliation, everytime a new slave attaches to the master, we need to
* flush our cache of scripts that can be replicated as EVALSHA, while
* for AOF we need to do so every time we rewrite the AOF file. */
if (evalsha) {
if (!replicationScriptCacheExists(c->argv[1]->ptr)) {
/* This script is not in our script cache, replicate it as
* EVAL, then add it into the script cache, as from now on
* slaves and AOF know about it. */
robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
replicationScriptCacheAdd(c->argv[1]->ptr);
redisAssertWithInfo(c,NULL,script != NULL);
rewriteClientCommandArgument(c,0,
resetRefCount(createStringObject("EVAL",4)));
rewriteClientCommandArgument(c,1,script);
forceCommandPropagation(c,REDIS_PROPAGATE_REPL|REDIS_PROPAGATE_AOF);
}
}
}
void evalGenericCommand(redisClient *c, int evalsha) {
lua_State *lua = server.lua;
char funcname[43];
long long numkeys;
int delhook = 0;
/* We want the same PRNG sequence at every call so that our PRNG is
* not affected by external state. */
redisSrand48(0);
/* We set this flag to zero to remember that so far no random command
* was called. This way we can allow the user to call commands like
* SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
* is called (otherwise the replication and AOF would end with non
* deterministic sequences).
*
* Thanks to this flag we'll raise an error every time a write command
* is called after a random command was used. */
server.lua_random_dirty = 0;
server.lua_write_dirty = 0;
/* Get the number of arguments that are keys */
if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
return;
if (numkeys > (c->argc - 3)) {
addReplyError(c,"Number of keys can't be greater than number of args");
return;
}
/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
funcname[0] = 'f';
funcname[1] = '_';
if (!evalsha) {
/* Hash the code if this is an EVAL call */
sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
} else {
/* We already have the SHA if it is a EVALSHA */
int j;
char *sha = c->argv[1]->ptr;
for (j = 0; j < 40; j++)
funcname[j+2] = tolower(sha[j]);
funcname[42] = '\0';
}
/* Try to lookup the Lua function */
lua_getglobal(lua, funcname);
if (lua_isnil(lua,1)) {
lua_pop(lua,1); /* remove the nil from the stack */
/* Function not defined... let's define it if we have the
* body of the funciton. If this is an EVALSHA call we can just
* return an error. */
if (evalsha) {
addReply(c, shared.noscripterr);
return;
}
if (luaCreateFunction(c,lua,funcname,c->argv[1]) == REDIS_ERR) return;
/* Now the following is guaranteed to return non nil */
lua_getglobal(lua, funcname);
redisAssert(!lua_isnil(lua,1));
}
/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
/* Select the right DB in the context of the Lua client */
selectDb(server.lua_client,c->db->id);
/* Set an hook in order to be able to stop the script execution if it
* is running for too much time.
* We set the hook only if the time limit is enabled as the hook will
* make the Lua script execution slower. */
server.lua_caller = c;
server.lua_time_start = ustime()/1000;
server.lua_kill = 0;
if (server.lua_time_limit > 0 && server.masterhost == NULL) {
lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
delhook = 1;
}
/* At this point whatever this script was never seen before or if it was
* already defined, we can call it. We have zero arguments and expect
* a single return value. */
if (lua_pcall(lua,0,1,0)) {
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
if (server.lua_timedout) {
server.lua_timedout = 0;
/* Restore the readable handler that was unregistered when the
* script timeout was detected. */
aeCreateFileEvent(server.el,c->fd,AE_READABLE,
readQueryFromClient,c);
}
server.lua_caller = NULL;
selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
funcname, lua_tostring(lua,-1));
lua_pop(lua,1);
lua_gc(lua,LUA_GCCOLLECT,0);
return;
}
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
server.lua_timedout = 0;
server.lua_caller = NULL;
selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
luaReplyToRedisReply(c,lua);
lua_gc(lua,LUA_GCSTEP,1);
/* If we have slaves attached we want to replicate this command as
* EVAL instead of EVALSHA. We do this also in the AOF as currently there
* is no easy way to propagate a command in a different way in the AOF
* and in the replication link.
*
* IMPROVEMENT POSSIBLE:
* 1) Replicate this command as EVALSHA in the AOF.
* 2) Remember what slave already received a given script, and replicate
* the EVALSHA against this slaves when possible.
*/
if (evalsha) {
robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
redisAssertWithInfo(c,NULL,script != NULL);
rewriteClientCommandArgument(c,0,
resetRefCount(createStringObject("EVAL",4)));
rewriteClientCommandArgument(c,1,script);
}
}
void evalGenericCommand(redisClient *c, int evalsha)
{
lua_State *lua = server.lua;
char funcname[43];
long long numkeys;
int delhook = 0;
/* We want the same PRNG sequence at every call so that our PRNG is
* not affected by external state.
*
* 在每次执行 EVAL 时重置随机 seed ，从而保证可以生成相同的随机序列。
*/
redisSrand48(0);
/* We set this flag to zero to remember that so far no random command
* was called. This way we can allow the user to call commands like
* SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
* is called (otherwise the replication and AOF would end with non
* deterministic sequences).
*
* Thanks to this flag we'll raise an error every time a write command
* is called after a random command was used.
*
* 用两个变量，对命令进行检查
* 确保在调用随机命令之后，再调用写命令将出现错误
*/
server.lua_random_dirty = 0;
server.lua_write_dirty = 0;
/* Get the number of arguments that are keys */
// 获取输入键的数量
if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
return;
// 对键的正确性做一个快速检查
if (numkeys > (c->argc - 3))
{
addReplyError(c,"Number of keys can't be greater than number of args");
return;
}
/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
// 组合出函数的名字，例如 f_282297a0228f48cd3fc6a55de6316f31422f5d17
funcname[0] = 'f';
funcname[1] = '_';
if (!evalsha)
{
/* Hash the code if this is an EVAL call */
// 如果执行的是 EVAL 命令，那么计算脚本的 SHA1 校验和
sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
}
else
{
// 如果执行的是 EVALSHA 命令，直接使用传入的 SHA1 值
/* We already have the SHA if it is a EVALSHA */
int j;
char *sha = c->argv[1]->ptr;
for (j = 0; j < 40; j++)
funcname[j+2] = tolower(sha[j]);
funcname[42] = '\0';
}
/* Try to lookup the Lua function */
// 按名查找函数
lua_getglobal(lua, funcname);
if (lua_isnil(lua,1))
{
// 没找到脚本相应的脚本
lua_pop(lua,1); /* remove the nil from the stack */
/* Function not defined... let's define it if we have the
* body of the funciton. If this is an EVALSHA call we can just
* return an error. */
if (evalsha)
{
// 如果执行的是 EVALSHA ，返回脚本未找到错误
addReply(c, shared.noscripterr);
return;
}
// 如果执行的是 EVAL ，那么创建并执行新函数，然后将代码添加到脚本字典中
if (luaCreateFunction(c,lua,funcname,c->argv[1]) == REDIS_ERR) return;
/* Now the following is guaranteed to return non nil */
lua_getglobal(lua, funcname);
redisAssert(!lua_isnil(lua,1));
}
/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
// 设置 KEYS 和 ARGV 全局变量到 Lua 环境
luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
/* Select the right DB in the context of the Lua client */
// 为 Lua 所属的（伪）客户端设置数据库
selectDb(server.lua_client,c->db->id);
/* Set an hook in order to be able to stop the script execution if it
* is running for too much time.
*
* 设置一个钩子，用于在运行时间过长时停止脚本的运作。
*
* We set the hook only if the time limit is enabled as the hook will
* make the Lua script execution slower.
*
* 只在开启了时间限制选项时使用钩子，因为它会拖慢脚本的运行速度。
*/
// 调用客户端
server.lua_caller = c;
// 脚本开始时间
server.lua_time_start = ustime()/1000;
// 是否杀死脚本
server.lua_kill = 0;
// 只在开启时间限制时使用钩子
if (server.lua_time_limit > 0 && server.masterhost == NULL)
{
lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
delhook = 1;
}
/* At this point whatever this script was never seen before or if it was
* already defined, we can call it. We have zero arguments and expect
* a single return value. */
// 执行脚本（所属的函数）
if (lua_pcall(lua,0,1,0))
{
// 以下是脚本执行出错的代码。。。
// 删除钩子
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
// 脚本执行已超时
if (server.lua_timedout)
{
// 清除超时 FLAG
server.lua_timedout = 0;
/* Restore the readable handler that was unregistered when the
* script timeout was detected. */
// 将超时钩子里删除的读事件重新加上
aeCreateFileEvent(server.el,c->fd,AE_READABLE,
readQueryFromClient,c);
}
// 清空调用者
server.lua_caller = NULL;
// 更新目标数据库
selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
funcname, lua_tostring(lua,-1));
// 弹出函数
lua_pop(lua,1);
// 执行完整的废料回首循环（full garbage-collection cycle）
lua_gc(lua,LUA_GCCOLLECT,0);
// 返回
return;
}
// 以下是脚本执行成功时执行的代码。。。
// 删除钩子
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
// 清空超时 FLAG
server.lua_timedout = 0;
// 清空调用者
server.lua_caller = NULL;
// 更新 DB
selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
// 将 Lua 回复转换成 Redis 回复
luaReplyToRedisReply(c,lua);
// 执行 1 步渐进式 GC
lua_gc(lua,LUA_GCSTEP,1);
/* If we have slaves attached we want to replicate this command as
* EVAL instead of EVALSHA. We do this also in the AOF as currently there
* is no easy way to propagate a command in a different way in the AOF
* and in the replication link.
*
* 如果有附属节点，那么使用 EVAL 而不是 EVALSHA 来传播脚本
* 因为目前还没有代码可以检测脚本是否已经传送到附属节点中
*
* IMPROVEMENT POSSIBLE:
* 1) Replicate this command as EVALSHA in the AOF.
* 2) Remember what slave already received a given script, and replicate
* the EVALSHA against this slaves when possible.
*/
// 如果执行的是 EVALSHA 命令
if (evalsha)
{
// 取出脚本代码体（body）
robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
redisAssertWithInfo(c,NULL,script != NULL);
// 重写客户端命令为 EVAL
rewriteClientCommandArgument(c,0,
resetRefCount(createStringObject("EVAL",4)));
rewriteClientCommandArgument(c,1,script);
}
}
void evalGenericCommand(rliteClient *c, int evalsha) {
scriptingInit();
lua_client->context = c->context;
char funcname[43];
long long numkeys;
int delhook = 0, err;
/* We want the same PRNG sequence at every call so that our PRNG is
* not affected by external state. */
rliteSrand48(0);
/* We set this flag to zero to remember that so far no random command
* was called. This way we can allow the user to call commands like
* SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
* is called (otherwise the replication and AOF would end with non
* deterministic sequences).
*
* Thanks to this flag we'll raise an error every time a write command
* is called after a random command was used. */
lua_random_dirty = 0;
lua_write_dirty = 0;
/* Get the number of arguments that are keys */
if (getLongLongFromObjectOrReply(c,c->argv[2],c->argvlen[2],&numkeys,NULL) != RLITE_OK)
return;
if (numkeys > (c->argc - 3)) {
c->reply = createErrorObject("Number of keys can't be greater than number of args");
return;
} else if (numkeys < 0) {
c->reply = createErrorObject("Number of keys can't be negative");
return;
}
/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
funcname[0] = 'f';
funcname[1] = '_';
if (!evalsha) {
/* Hash the code if this is an EVAL call */
sha1hex(funcname+2,c->argv[1],c->argvlen[1]);
} else {
/* We already have the SHA if it is a EVALSHA */
int j;
char *sha = c->argv[1];
/* Convert to lowercase. We don't use tolower since the function
* managed to always show up in the profiler output consuming
* a non trivial amount of time. */
for (j = 0; j < 40; j++)
funcname[j+2] = (sha[j] >= 'A' && sha[j] <= 'Z') ?
sha[j]+('a'-'A') : sha[j];
funcname[42] = '\0';
char *body;
long bodylen;
int retval = getScript(c, funcname + 2, &body, &bodylen);
if (retval != RL_OK) {
c->reply = createErrorObject(RLITE_NOSCRIPTERR);
return;
}
luaCreateFunction(c, lua, funcname, body, bodylen);
rl_free(body);
}
/* Push the pcall error handler function on the stack. */
lua_getglobal(lua, "__rlite__err__handler");
/* Try to lookup the Lua function */
lua_getglobal(lua, funcname);
if (lua_isnil(lua,-1)) {
lua_pop(lua,1); /* remove the nil from the stack */
/* Function not defined... let's define it if we have the
* body of the function. If this is an EVALSHA call we can just
* return an error. */
if (evalsha) {
lua_pop(lua,1); /* remove the error handler from the stack. */
c->reply = createErrorObject(RLITE_NOSCRIPTERR);
return;
}
if (luaCreateFunction(c,lua,funcname,c->argv[1], c->argvlen[1]) == RLITE_ERR) {
lua_pop(lua,1); /* remove the error handler from the stack. */
/* The error is sent to the client by luaCreateFunction()
* itself when it returns RLITE_ERR. */
return;
}
/* Now the following is guaranteed to return non nil */
lua_getglobal(lua, funcname);
if (lua_isnil(lua,-1)) {
// TODO: panic
return;
}
}
/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
luaSetGlobalArray(lua,"KEYS",c->argv+3,c->argvlen+3,numkeys);
luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argvlen+3+numkeys,c->argc-3-numkeys);
/* Set a hook in order to be able to stop the script execution if it
* is running for too much time.
* We set the hook only if the time limit is enabled as the hook will
* make the Lua script execution slower. */
lua_caller = c;
lua_time_start = rl_mstime();
lua_kill = 0;
if (lua_time_limit > 0) {
lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
delhook = 1;
}
/* At this point whether this script was never seen before or if it was
* already defined, we can call it. We have zero arguments and expect
* a single return value. */
err = lua_pcall(lua,0,1,-2);
/* Perform some cleanup that we need to do both on error and success. */
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
if (lua_timedout) {
lua_timedout = 0;
/* Restore the readable handler that was unregistered when the
* script timeout was detected. */
}
lua_caller = NULL;
/* Call the Lua garbage collector from time to time to avoid a
* full cycle performed by Lua, which adds too latency.
*
* The call is performed every LUA_GC_CYCLE_PERIOD executed commands
* (and for LUA_GC_CYCLE_PERIOD collection steps) because calling it
* for every command uses too much CPU. */
#define LUA_GC_CYCLE_PERIOD 50
{
static long gc_count = 0;
gc_count++;
if (gc_count == LUA_GC_CYCLE_PERIOD) {
lua_gc(lua,LUA_GCSTEP,LUA_GC_CYCLE_PERIOD);
gc_count = 0;
}
}
if (err) {
char err[1024];
snprintf(err, 1024, "Error running script (call to %s): %s\n",
funcname, lua_tostring(lua,-1));
c->reply = createErrorObject(err);
lua_pop(lua,2); /* Consume the Lua reply and remove error handler. */
} else {
/* On success convert the Lua return value into Redis protocol, and
* send it to * the client. */
luaReplyToRedisReply(c,lua); /* Convert and consume the reply. */
lua_pop(lua,1); /* Remove the error handler. */
}
}
/* *
* slotsrestore key ttl val [key ttl val ...]
* */
void
slotsrestoreCommand(redisClient *c) {
if (c->argc < 4 || (c->argc - 1) % 3 != 0) {
addReplyErrorFormat(c, "wrong number of arguments for 'slotsrestore' command");
return;
}
int n = (c->argc - 1) / 3;
long long *ttls = zmalloc(sizeof(long long) * n);
robj **vals = zmalloc(sizeof(robj *) * n);
for (int i = 0; i < n; i ++) {
vals[i] = NULL;
}
for (int i = 0; i < n; i ++) {
robj *key = c->argv[i * 3 + 1];
robj *ttl = c->argv[i * 3 + 2];
robj *val = c->argv[i * 3 + 3];
if (lookupKeyWrite(c->db, key) != NULL) {
redisLog(REDIS_WARNING, "slotsrestore: slot = %d, key = '%s' already exists",
slots_num(key->ptr, NULL), (char *)key->ptr);
}
if (getLongLongFromObjectOrReply(c, ttl, &ttls[i], NULL) != REDIS_OK) {
goto cleanup;
} else if (ttls[i] < 0) {
addReplyError(c, "invalid ttl value, must be >= 0");
goto cleanup;
}
rio payload;
int type;
if (verifyDumpPayload(val->ptr, sdslen(val->ptr)) != REDIS_OK) {
addReplyError(c, "dump payload version or checksum are wrong");
goto cleanup;
}
rioInitWithBuffer(&payload, val->ptr);
if (((type = rdbLoadObjectType(&payload)) == -1) ||
((vals[i] = rdbLoadObject(type, &payload)) == NULL)) {
addReplyError(c, "bad data format");
goto cleanup;
}
}
for (int i = 0; i < n; i ++) {
robj *key = c->argv[i * 3 + 1];
long long ttl = ttls[i];
robj *val = vals[i];
dbDelete(c->db, key);
dbAdd(c->db, key, val);
incrRefCount(val);
if (ttl) {
setExpire(c->db, key, mstime() + ttl);
}
signalModifiedKey(c->db, key);
server.dirty ++;
}
addReply(c, shared.ok);
cleanup:
for (int i = 0; i < n; i ++) {
if (vals[i] != NULL) {
decrRefCount(vals[i]);
}
}
zfree(vals);
zfree(ttls);
}
void evalGenericCommand(redisClient *c, int evalsha) {
lua_State *lua = server.lua;
char funcname[43];
long long numkeys;
int delhook = 0, err;
// 随机数的种子，在产生哈希值的时候会用到
/* We want the same PRNG sequence at every call so that our PRNG is
* not affected by external state. */
redisSrand48(0);
/* We set this flag to zero to remember that so far no random command
* was called. This way we can allow the user to call commands like
* SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
* is called (otherwise the replication and AOF would end with non
* deterministic sequences).
*
* Thanks to this flag we'll raise an error every time a write command
* is called after a random command was used. */
server.lua_random_dirty = 0;
server.lua_write_dirty = 0;
// 检查参数的有效性
/* Get the number of arguments that are keys */
if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
return;
if (numkeys > (c->argc - 3)) {
addReplyError(c,"Number of keys can't be greater than number of args");
return;
}
// 函数名以 f_ 开头
/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
funcname[0] = 'f';
funcname[1] = '_';
// 如果没有哈希值，需要计算 lua 脚本的哈希值
if (!evalsha) {
// 计算哈希值，会放入到 SHA1 -> lua_script 哈希表中
// c->argv[1]->ptr 是用户指定的 lua 脚本
// sha1hex() 产生的哈希值存在 funcname 中
/* Hash the code if this is an EVAL call */
sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
} else {
// 用户自己指定了哈希值
/* We already have the SHA if it is a EVALSHA */
int j;
char *sha = c->argv[1]->ptr;
for (j = 0; j < 40; j++)
funcname[j+2] = tolower(sha[j]);
funcname[42] = '\0';
}
// 将错误处理函数入栈
// lua_getglobal() 会将读取指定的全局变量，且将其入栈
/* Push the pcall error handler function on the stack. */
lua_getglobal(lua, "__redis__err__handler");
/* Try to lookup the Lua function */
// 在 lua 中查找是否注册了此函数。这一句尝试将 funcname 入栈
lua_getglobal(lua, funcname);
if (lua_isnil(lua,-1)) { // funcname 在 lua 中不存在
// 将 nil 出栈
lua_pop(lua,1); /* remove the nil from the stack */
// 已经确定 funcname 在 lua 中没有定义，需要创建
/* Function not defined... let's define it if we have the
* body of the function. If this is an EVALSHA call we can just
* return an error. */
if (evalsha) {
lua_pop(lua,1); /* remove the error handler from the stack. */
addReply(c, shared.noscripterr);
return;
}
// 创建 lua 函数 funcname
// c->argv[1] 指向用户指定的 lua 脚本
if (luaCreateFunction(c,lua,funcname,c->argv[1]) == REDIS_ERR) {
lua_pop(lua,1); /* remove the error handler from the stack. */
/* The error is sent to the client by luaCreateFunction()
* itself when it returns REDIS_ERR. */
return;
}
// 现在 lua 中已经有 funcname 这个全局变量了，将其读取并入栈，
// 准备调用
/* Now the following is guaranteed to return non nil */
lua_getglobal(lua, funcname);
redisAssert(!lua_isnil(lua,-1));
}
// 设置参数，包括键和值
/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
// 选择数据集，lua_client 有专用的数据集
/* Select the right DB in the context of the Lua client */
selectDb(server.lua_client,c->db->id);
// 设置超时回调函数，以在 lua 脚本执行过长时间的时候停止脚本的运行
/* Set a hook in order to be able to stop the script execution if it
* is running for too much time.
* We set the hook only if the time limit is enabled as the hook will
* make the Lua script execution slower. */
server.lua_caller = c;
server.lua_time_start = ustime()/1000;
server.lua_kill = 0;
if (server.lua_time_limit > 0 && server.masterhost == NULL) {
// 当 lua 解释器执行了 100000，luaMaskCountHook() 会被调用
lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
delhook = 1;
}
// 现在，我们确定函数已经注册成功了.可以直接调用 lua 脚本
/* At this point whether this script was never seen before or if it was
* already defined, we can call it. We have zero arguments and expect
* a single return value. */
err = lua_pcall(lua,0,1,-2);
// 删除超时回调函数
/* Perform some cleanup that we need to do both on error and success. */
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
// 如果已经超时了，说明 lua 脚本已在超时后背 SCRPIT KILL 终结了
// 恢复监听发送 lua 脚本命令的客户端
if (server.lua_timedout) {
server.lua_timedout = 0;
/* Restore the readable handler that was unregistered when the
* script timeout was detected. */
aeCreateFileEvent(server.el,c->fd,AE_READABLE,
readQueryFromClient,c);
}
// lua_caller 置空
server.lua_caller = NULL;
// 执行 lua 脚本用的是 lua 脚本执行专用的数据集。现在恢复原有的数据集
selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
// Garbage collection 垃圾回收
lua_gc(lua,LUA_GCSTEP,1);
// 处理执行 lua 脚本的错误
if (err) {
// 告知客户端
addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
funcname, lua_tostring(lua,-1));
lua_pop(lua,2); /* Consume the Lua reply and remove error handler. */
// 成功了
} else {
/* On success convert the Lua return value into Redis protocol, and
* send it to * the client. */
luaReplyToRedisReply(c,lua); /* Convert and consume the reply. */
lua_pop(lua,1); /* Remove the error handler. */
}
// 将 lua 脚本发布到主从复制上，并写入 AOF 文件
/* EVALSHA should be propagated to Slave and AOF file as full EVAL, unless
* we are sure that the script was already in the context of all the
* attached slaves *and* the current AOF file if enabled.
*
* To do so we use a cache of SHA1s of scripts that we already propagated
* as full EVAL, that's called the Replication Script Cache.
*
* For repliation, everytime a new slave attaches to the master, we need to
* flush our cache of scripts that can be replicated as EVALSHA, while
* for AOF we need to do so every time we rewrite the AOF file. */
if (evalsha) {
if (!replicationScriptCacheExists(c->argv[1]->ptr)) {
/* This script is not in our script cache, replicate it as
* EVAL, then add it into the script cache, as from now on
* slaves and AOF know about it. */
// 从 server.lua_scripts 获取 lua 脚本
// c->argv[1]->ptr 是 SHA1
robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
// 添加到主从复制专用的脚本缓存中
replicationScriptCacheAdd(c->argv[1]->ptr);
redisAssertWithInfo(c,NULL,script != NULL);
// 重写命令
// 参数 1 为：EVAL
// 参数 2 为：lua_script
// 如此一来在执行 AOF 持久化和主从复制的时候，lua 脚本就能得到传播
rewriteClientCommandArgument(c,0,
resetRefCount(createStringObject("EVAL",4)));
rewriteClientCommandArgument(c,1,script);
}
}
}