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SORT is now more deterministic: does not accept to compare by score items that have scores not representing a valid double. Also items with the same score are compared lexycographically. At the same time the scripting side introduced the ability to sort the output of SORT when sort uses the BY <constant> optimization, resulting in no specific ordering. Since in this case the user may use GET, and the result of GET can be null, converted into false as Lua data type, this commit also introduces the ability to sort Lua tables containining false, only if the first (faster) attempt at using just table.sort with a single argument fails.

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antirez
2012-02-01 15:22:28 +01:00
parent 548efd91e5
commit 2c861050c1
5 changed files with 52 additions and 7 deletions
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33
src/scripting.c
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@ -140,7 +140,22 @@ void luaSortArray(lua_State *lua) {
lua_pushstring(lua,"sort");
lua_gettable(lua,-2); /* Stack: array, table, table.sort */
lua_pushvalue(lua,-3); /* Stack: array, table, table.sort, array */
lua_call(lua,1,0); /* Stack: array (sorted), table */
if (lua_pcall(lua,1,0,0)) {
/* Stack: array, table, error */
/* We are not interested in the error, we assume that the problem is
* that there are 'false' elements inside the array, so we try
* again with a slower function but able to handle this case, that
* is: table.sort(table, __redis__compare_helper) */
lua_pop(lua,1); /* Stack: array, table */
lua_pushstring(lua,"sort"); /* Stack: array, table, sort */
lua_gettable(lua,-2); /* Stack: array, table, table.sort */
lua_pushvalue(lua,-3); /* Stack: array, table, table.sort, array */
lua_getglobal(lua,"__redis__compare_helper");
/* Stack: array, table, table.sort, array, __redis__compare_helper */
lua_call(lua,2,0);
}
/* Stack: array (sorted), table */
lua_pop(lua,1); /* Stack: array (sorted) */
}
@ -228,7 +243,9 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) {
* reply as expected. */
if ((cmd->flags & REDIS_CMD_SORT_FOR_SCRIPT) &&
(reply[0] == '*' && reply[1] != '-')) {
luaSortArray(lua);
/* Skip this step if command is SORT but output was already sorted */
if (cmd->proc != sortCommand || server.sort_dontsort)
luaSortArray(lua);
}
sdsfree(reply);
@ -403,6 +420,18 @@ void scriptingInit(void) {
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. */
{
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.
* Note: there is no need to create it again when this function is called