Redis Functions - Introduce script unit.

Script unit is a new unit located on script.c.
Its purpose is to provides an API for functions (and eval)
to interact with Redis. Interaction includes mostly
executing commands, but also functionalities like calling
Redis back on long scripts or check if the script was killed.

The interaction is done using a scriptRunCtx object that
need to be created by the user and initialized using scriptPrepareForRun.

Detailed list of functionalities expose by the unit:
1. Calling commands (including all the validation checks such as
   acl, cluster, read only run, ...)
2. Set Resp
3. Set Replication method (AOF/REPLICATION/NONE)
4. Call Redis back to on long running scripts to allow Redis reply
   to clients and perform script kill

The commit introduce the new unit and uses it on eval commands to
interact with Redis.

1 files changed, 25 insertions, 21 deletions

diff --git a/src/script_lua.h b/src/script_lua.h
index f9cf6f18a..5ae9225bc 100644
--- a/src/script_lua.h
+++ b/src/script_lua.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009-2021, Redis Labs Ltd.
+ * Copyright (c) 2009-2021, Redis Ltd.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -30,35 +30,39 @@
 #ifndef __SCRIPT_LUA_H_
 #define __SCRIPT_LUA_H_
 
+/*
+ * script_lua.c unit provides shared functionality between
+ * eval.c and function_lua.c. Functionality provided:
+ *
+ * * Execute Lua code, assuming that the code is located on
+ *   the top of the Lua stack. In addition, parsing the execution
+ *   result and convert it to the resp and reply ot the client.
+ *
+ * * Run Redis commands from within the Lua code (Including
+ *   parsing the reply and create a Lua object out of it).
+ *
+ * * Register Redis API to the Lua interpreter. Only shared
+ *   API are registered (API that is only relevant on eval.c
+ *   (like debugging) are registered on eval.c).
+ *
+ * Uses script.c for interaction back with Redis.
+ */
+
 #include "server.h"
 #include "script.h"
 #include <lua.h>
 #include <lauxlib.h>
 #include <lualib.h>
 
-typedef struct luaCtx {
-    lua_State *lua; /* The Lua interpreter. We use just one for all clients */
-    client *lua_client;   /* The "fake client" to query Redis from Lua */
-    char *lua_cur_script; /* SHA1 of the script currently running, or NULL */
-    dict *lua_scripts;         /* A dictionary of SHA1 -> Lua scripts */
-    unsigned long long lua_scripts_mem;  /* Cached scripts' memory + oh */
-    int lua_replicate_commands; /* True if we are doing single commands repl. */
-    int lua_write_dirty;
-    int lua_random_dirty;
-    int lua_multi_emitted;
-    int lua_repl;
-    int lua_kill;
-    monotime lua_time_start;  /* monotonic timer to detect timed-out script */
-    mstime_t lua_time_snapshot; /* Snapshot of mstime when script is started */
-} luaCtx;
-
-extern luaCtx lctx;
+#define REGISTRY_RUN_CTX_NAME "__RUN_CTX__"
 
-void luaEngineRegisterRedisAPI(lua_State* lua);
-void scriptingEnableGlobalsProtection(lua_State *lua);
+void luaRegisterRedisAPI(lua_State* lua);
+void luaEnableGlobalsProtection(lua_State *lua);
 void luaSetGlobalArray(lua_State *lua, char *var, robj **elev, int elec);
 void luaMaskCountHook(lua_State *lua, lua_Debug *ar);
-void luaReplyToRedisReply(client *c, lua_State *lua);
+void luaReplyToRedisReply(client *c, client* script_client, lua_State *lua);
+void luaSaveOnRegistry(lua_State* lua, const char* name, void* ptr);
+void* luaGetFromRegistry(lua_State* lua, const char* name);