Enforced that upb_msg lives in an Arena only, and other simplifying.

upb_msg was trying to be general enough that it could either live in
an arena or be allocated with malloc()/free().  This was too much
complexity for too little benefit.  We should commit to just saying
that upb_msg is arena-only.

I also ripped out the code to glue upb_msg to the existing
handlers-based encoder/decoder.  upb_msg has its own, small, simple
encoder/decoder.  I'm trying to whittle down upb_msg to a small
and simple core.

I updated the Lua extension for these changes.  Lua needs some more
work to properly create arenas per message.  For now I just created
a single global arena.

1 files changed, 18 insertions, 99 deletions

diff --git a/upb/bindings/lua/upb/pb.c b/upb/bindings/lua/upb/pb.c
index 1d56066..466e8f7 100644
--- a/upb/bindings/lua/upb/pb.c
+++ b/upb/bindings/lua/upb/pb.c
@@ -6,135 +6,56 @@
 */
 
 #include "upb/bindings/lua/upb.h"
-#include "upb/pb/decoder.h"
-#include "upb/pb/encoder.h"
+#include "upb/decode.h"
+#include "upb/encode.h"
 
 #define LUPB_PBDECODERMETHOD "lupb.pb.decodermethod"
 
-static int lupb_pb_strtomessage(lua_State *L) {
+static int lupb_pb_decode(lua_State *L) {
   size_t len;
   upb_status status = UPB_STATUS_INIT;
-  const char *pb = lua_tolstring(L, 1, &len);
-  const upb_msglayout *layout = lua_touserdata(L, lua_upvalueindex(1));
-  const upb_pbdecodermethod *method = lua_touserdata(L, lua_upvalueindex(2));
-  const upb_handlers *handlers = upb_pbdecodermethod_desthandlers(method);
-
-  upb_arena *msg_arena;
+  const upb_msglayout *layout;
+  upb_msg *msg = lupb_msg_checkmsg2(L, 1, &layout);
+  const char *pb = lua_tolstring(L, 2, &len);
+  upb_stringview buf = upb_stringview_make(pb, len);
   upb_env env;
-  upb_sink sink;
-  upb_pbdecoder *decoder;
-  void *msg;
-
-  lupb_arena_new(L);
-  msg_arena = lupb_arena_check(L, -1);
 
-  msg = upb_msg_new(layout, upb_arena_alloc(msg_arena));
   upb_env_init(&env);
   upb_env_reporterrorsto(&env, &status);
-  upb_sink_reset(&sink, handlers, msg);
-  decoder = upb_pbdecoder_create(&env, method, &sink);
 
-  upb_bufsrc_putbuf(pb, len, upb_pbdecoder_input(decoder));
+  upb_decode(buf, msg, (const void*)layout, &env);
 
   /* Free resources before we potentially bail on error. */
   upb_env_uninit(&env);
   lupb_checkstatus(L, &status);
 
-  /* References the arena at the top of the stack. */
-  lupb_msg_pushref(L, lua_upvalueindex(3), msg);
-  return 1;
+  return 0;
 }
 
-static int lupb_pb_messagetostr(lua_State *L) {
-  const lupb_msgclass *lmsgclass = lua_touserdata(L, lua_upvalueindex(1));
-  const upb_msg *msg = lupb_msg_checkmsg(L, 1, lmsgclass);
-  const upb_visitorplan *vp = lua_touserdata(L, lua_upvalueindex(2));
-  const upb_handlers *encode_handlers = lua_touserdata(L, lua_upvalueindex(3));
-
+static int lupb_pb_encode(lua_State *L) {
+  const upb_msglayout *layout;
+  const upb_msg *msg = lupb_msg_checkmsg2(L, 1, &layout);
   upb_env env;
-  upb_bufsink *bufsink;
-  upb_bytessink *bytessink;
-  upb_pb_encoder *encoder;
-  upb_visitor *visitor;
-  const char *buf;
-  size_t len;
+  size_t size;
   upb_status status = UPB_STATUS_INIT;
+  char *result;
 
   upb_env_init(&env);
   upb_env_reporterrorsto(&env, &status);
-  bufsink = upb_bufsink_new(&env);
-  bytessink = upb_bufsink_sink(bufsink);
-  encoder = upb_pb_encoder_create(&env, encode_handlers, bytessink);
-  visitor = upb_visitor_create(&env, vp, upb_pb_encoder_input(encoder));
 
-  upb_visitor_visitmsg(visitor, msg);
-  buf = upb_bufsink_getdata(bufsink, &len);
-  lua_pushlstring(L, buf, len);
+  result = upb_encode(msg, (const void*)layout, &env, &size);
 
   /* Free resources before we potentially bail on error. */
   upb_env_uninit(&env);
   lupb_checkstatus(L, &status);
 
+  lua_pushlstring(L, result, size);
   return 1;
 }
 
-static int lupb_pb_makestrtomsgdecoder(lua_State *L) {
-  const upb_msglayout *layout = lupb_msgclass_getlayout(L, 1);
-  const upb_handlers *handlers = lupb_msgclass_getmergehandlers(L, 1);
-  const upb_pbdecodermethod *m;
-
-  upb_pbdecodermethodopts opts;
-  upb_pbdecodermethodopts_init(&opts, handlers);
-
-  m = upb_pbdecodermethod_new(&opts, &m);
-
-  /* Push upvalues for the closure. */
-  lua_pushlightuserdata(L, (void*)layout);
-  lua_pushlightuserdata(L, (void*)m);
-  lua_pushvalue(L, 1);
-
-  /* Upvalue for the closure, only to keep the decodermethod alive. */
-  lupb_refcounted_pushnewrapper(
-      L, upb_pbdecodermethod_upcast(m), LUPB_PBDECODERMETHOD, &m);
-
-  lua_pushcclosure(L, &lupb_pb_strtomessage, 4);
-
-  return 1;  /* The decoder closure. */
-}
-
-static int lupb_pb_makemsgtostrencoder(lua_State *L) {
-  const lupb_msgclass *lmsgclass = lupb_msgclass_check(L, 1);
-  const upb_msgdef *md = lupb_msgclass_getmsgdef(lmsgclass);
-  upb_msgfactory *factory = lupb_msgclass_getfactory(lmsgclass);
-  const upb_handlers *encode_handlers;
-  const upb_visitorplan *vp;
-
-  encode_handlers = upb_pb_encoder_newhandlers(md, &encode_handlers);
-  vp = upb_msgfactory_getvisitorplan(factory, encode_handlers);
-
-  /* Push upvalues for the closure. */
-  lua_pushlightuserdata(L, (void*)lmsgclass);
-  lua_pushlightuserdata(L, (void*)vp);
-  lua_pushlightuserdata(L, (void*)encode_handlers);
-
-  /* Upvalues for the closure, only to keep the other upvalues alive. */
-  lua_pushvalue(L, 1);
-  lupb_refcounted_pushnewrapper(
-      L, upb_handlers_upcast(encode_handlers), LUPB_PBDECODERMETHOD, &encode_handlers);
-
-  lua_pushcclosure(L, &lupb_pb_messagetostr, 5);
-
-  return 1;  /* The decoder closure. */
-}
-
-static const struct luaL_Reg decodermethod_mm[] = {
-  {"__gc", lupb_refcounted_gc},
-  {NULL, NULL}
-};
-
 static const struct luaL_Reg toplevel_m[] = {
-  {"MakeStringToMessageDecoder", lupb_pb_makestrtomsgdecoder},
-  {"MakeMessageToStringEncoder", lupb_pb_makemsgtostrencoder},
+  {"decode", lupb_pb_decode},
+  {"encode", lupb_pb_encode},
   {NULL, NULL}
 };
 
@@ -144,7 +65,5 @@ int luaopen_upb_pb_c(lua_State *L) {
     return 1;
   }
 
-  lupb_register_type(L, LUPB_PBDECODERMETHOD, NULL, decodermethod_mm);
-
   return 1;
 }