From d3a4dc6823284d071a231f6323ff98f5fc0f6964 Mon Sep 17 00:00:00 2001
From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Date: Sat, 18 Apr 2020 23:05:12 +0200
Subject: [PATCH] box: move Lua MP_EXT decoder from tuple.c

Lua C module 'msgpack' supports registration of custom extension
decoders for MP_EXT values. That is needed to make 'msgpack' not
depending on any modules which use it.

So far the only box-related extension were tuples - struct tuple
cdata needed to be encoded as an array.

That is going to change in next commits, where struct error cdata
appears, also depending on box. So the decoder can't be located
in src/box/lua/tuple.c. It is moved to a more common place -
src/box/lua/init.c.

Needed for #4398
---
 src/box/lua/init.c  | 18 ++++++++++++++++++
 src/box/lua/tuple.c | 16 ----------------
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/box/lua/init.c b/src/box/lua/init.c
index 0a65c3b563..7899c16cb3 100644
--- a/src/box/lua/init.c
+++ b/src/box/lua/init.c
@@ -36,6 +36,7 @@
 
 #include "lua/utils.h" /* luaT_error() */
 #include "lua/trigger.h"
+#include "lua/msgpack.h"
 
 #include "box/box.h"
 #include "box/txn.h"
@@ -395,6 +396,21 @@ static const struct luaL_Reg boxlib_backup[] = {
 	{NULL, NULL}
 };
 
+/**
+ * A MsgPack extensions handler, for types defined in box.
+ */
+static enum mp_type
+luamp_encode_extension_box(struct lua_State *L, int idx,
+			   struct mpstream *stream)
+{
+	struct tuple *tuple = luaT_istuple(L, idx);
+	if (tuple != NULL) {
+		tuple_to_mpstream(tuple, stream);
+		return MP_ARRAY;
+	}
+	return MP_EXT;
+}
+
 #include "say.h"
 
 void
@@ -435,6 +451,8 @@ box_lua_init(struct lua_State *L)
 	luaopen_merger(L);
 	lua_pop(L, 1);
 
+	luamp_set_encode_extension(luamp_encode_extension_box);
+
 	/* Load Lua extension */
 	for (const char **s = lua_sources; *s; s += 2) {
 		const char *modname = *s;
diff --git a/src/box/lua/tuple.c b/src/box/lua/tuple.c
index aba906d1f2..03b4b8a2e3 100644
--- a/src/box/lua/tuple.c
+++ b/src/box/lua/tuple.c
@@ -290,20 +290,6 @@ tuple_to_mpstream(struct tuple *tuple, struct mpstream *stream)
 	mpstream_advance(stream, bsize);
 }
 
-/* A MsgPack extensions handler that supports tuples */
-static enum mp_type
-luamp_encode_extension_box(struct lua_State *L, int idx,
-			   struct mpstream *stream)
-{
-	struct tuple *tuple = luaT_istuple(L, idx);
-	if (tuple != NULL) {
-		tuple_to_mpstream(tuple, stream);
-		return MP_ARRAY;
-	}
-
-	return MP_EXT;
-}
-
 /**
  * Convert a tuple into lua table. Named fields are stored as
  * {name = value} pairs. Not named fields are stored as
@@ -582,8 +568,6 @@ box_lua_tuple_init(struct lua_State *L)
 	luaL_register_module(L, tuplelib_name, lbox_tuplelib);
 	lua_pop(L, 1);
 
-	luamp_set_encode_extension(luamp_encode_extension_box);
-
 	tuple_serializer_update_options();
 	trigger_create(&tuple_serializer.update_trigger,
 		       on_msgpack_serializer_update, NULL, NULL);
-- 
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