lib-lua: Store script pointer in LUA_REGISTRY

This will allow us to translate any lua thread to a script pointer.  This is
not meant to allow multi-threaded lua scripts, but it is necessary to allow
yields to work.

diff --git a/src/lib-lua/dlua-script.c b/src/lib-lua/dlua-script.c
index be7f24df42466888f7b08108341747e635037460..d5e85718095f20206cdfb737d66f92f906a5b2e4 100644 (file)
--- a/src/lib-lua/dlua-script.c
+++ b/src/lib-lua/dlua-script.c
@@ -12,6 +12,9 @@
 #include <fcntl.h>
 #include <unistd.h>
 
+/* the registry entry with a pointer to struct dlua_script */
+#define LUA_SCRIPT_REGISTRY_KEY        "DLUA_SCRIPT"
+
 #define LUA_SCRIPT_INIT_FN "script_init"
 #define LUA_SCRIPT_DEINIT_FN "script_deinit"
 
@@ -85,10 +88,15 @@ static const char *dlua_reader(lua_State *L, void *ctx, size_t *size_r)
 struct dlua_script *dlua_script_from_state(lua_State *L)
 {
        struct dlua_script *script;
-       for(script = dlua_scripts; script != NULL; script = script->next)
-               if (script->L == L)
-                       return script;
-       i_unreached();
+
+       /* get light pointer from globals */
+       lua_pushstring(L, LUA_SCRIPT_REGISTRY_KEY);
+       lua_gettable(L, LUA_REGISTRYINDEX);
+       script = lua_touserdata(L, -1);
+       lua_pop(L, 1);
+       i_assert(script != NULL);
+
+       return script;
 }
 
 int dlua_script_init(struct dlua_script *script, const char **error_r)
@@ -167,6 +175,11 @@ static int
 dlua_script_create_finish(struct dlua_script *script, struct dlua_script **script_r,
                          const char **error_r)
 {
+       /* store pointer as light data to registry before calling the script */
+       lua_pushstring(script->L, LUA_SCRIPT_REGISTRY_KEY);
+       lua_pushlightuserdata(script->L, script);
+       lua_settable(script->L, LUA_REGISTRYINDEX);
+
        if (dlua_run_script(script, error_r) < 0) {
                dlua_script_unref(&script);
                return -1;