From: Donald Lee <dlqs@gmx.com>
Date: Mon, 9 Aug 2021 23:07:06 +0000 (+0800)
Subject: lib: Enable consecutive frrscript_call
X-Git-Tag: base_8.1~215^2~2
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=2ed598ba6bdbd8b6b6c6e9a091faad15306d19de;p=matthieu%2Ffrr.git

lib: Enable consecutive frrscript_call

Previous:
 - frrscript_load: push Lua function onto stack
 - frrscript_call: calls Lua function

Now:
 - frrscript_load: checks Lua function
 - frrscript_call: pushes and calls Lua function (first clear the stack)

So now we just need one frrscript_load for consecutive frrscript_call.
frrscript_call does not recompile or reload the script file, it just
keys it from the global Lua table (where it should already be).

Signed-off-by: Donald Lee <dlqs@gmx.com>
---

diff --git a/lib/frrscript.c b/lib/frrscript.c
index c9fc938997..0e0d3c030c 100644
--- a/lib/frrscript.c
+++ b/lib/frrscript.c
@@ -288,13 +288,16 @@ int frrscript_load(struct frrscript *fs, const char *function_name,
 		goto fail;
 	}
 
-	/* Push the Lua function we want */
+	/* To check the Lua function, we get it from the global table */
 	lua_getglobal(L, function_name);
 	if (lua_isfunction(L, lua_gettop(L)) == 0) {
 		zlog_err("frrscript: loaded script '%s.lua' but %s not found",
 			 script_name, function_name);
 		goto fail;
 	}
+	/* Then pop the function (frrscript_call will push it when it needs it)
+	 */
+	lua_pop(L, 1);
 
 	if (load_cb && (*load_cb)(fs) != 0) {
 		zlog_err(
diff --git a/lib/frrscript.h b/lib/frrscript.h
index 540676c099..c089df61fc 100644
--- a/lib/frrscript.h
+++ b/lib/frrscript.h
@@ -203,8 +203,18 @@ const struct prefix * : lua_decode_noop                         \
 int _frrscript_call_lua(struct lua_function_state *lfs, int nargs);
 
 /*
- * Wrapper for calling Lua function state. Maps values passed in to their
- * encoder and decoder types.
+ * Wrapper for calling Lua function state.
+ *
+ * The Lua function name (f) to run should have already been checked by
+ * frrscript_load. So this wrapper will:
+ * 1) Find the Lua function state, which contains the Lua state
+ * 2) Clear the Lua state (there may be leftovers items from previous call)
+ * 3) Push the Lua function (f)
+ * 4) Map frrscript_call arguments onto their encoder and decoders, push those
+ * 5) Call _frrscript_call_lua (Lua execution takes place)
+ * 6) Write back to frrscript_call arguments using their decoders
+ *
+ * This wrapper can be called multiple times (after one frrscript_load).
  *
  * fs
  *    The struct frrscript in which the Lua fuction was loaded into
@@ -226,6 +236,8 @@ int _frrscript_call_lua(struct lua_function_state *lfs, int nargs);
 			1;                                                                                                                                         \
 		})                                                                                                                                                 \
 			    : ({                                                                                                                                   \
+				      lua_settop(lfs->L, 0);                                                                                                       \
+				      lua_getglobal(lfs->L, f);                                                                                                    \
 				      MAP_LISTS(ENCODE_ARGS, ##__VA_ARGS__);                                                                                       \
 				      _frrscript_call_lua(                                                                                                         \
 					      lfs, PP_NARG(__VA_ARGS__));                                                                                          \