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/*
* upb - a minimalist implementation of protocol buffers.
*
* Copyright (c) 2014 Google Inc. See LICENSE for details.
* Author: Josh Haberman <jhaberman@gmail.com>
*
* A Lua extension for upb.pb.
*
* Exposes all the types defined in upb/pb/{*}.h
* Also defines a few convenience functions on top.
*/
#include "upb/bindings/lua/upb.h"
#include "upb/pb/decoder.h"
#define LUPB_PBDECODERMETHOD "lupb.pb.decodermethod"
#define MSGDEF_INDEX 1
static upb_pbdecodermethod *lupb_pbdecodermethod_check(lua_State *L, int narg) {
return lupb_refcounted_check(L, narg, LUPB_PBDECODERMETHOD);
}
static int lupb_pbdecodermethod_new(lua_State *L) {
const upb_handlers *handlers = lupb_msg_newwritehandlers(L, 1, &handlers);
upb_pbdecodermethodopts opts;
upb_pbdecodermethodopts_init(&opts, handlers);
const upb_pbdecodermethod *m = upb_pbdecodermethod_new(&opts, &m);
upb_handlers_unref(handlers, &handlers);
lupb_refcounted_pushnewrapper(L, UPB_UPCAST(m), LUPB_PBDECODERMETHOD, &m);
// We need to keep a pointer to the MessageDef (in Lua space) so we can
// construct new messages in parse().
lua_newtable(L);
lua_pushvalue(L, 1);
lua_rawseti(L, -2, MSGDEF_INDEX);
lua_setuservalue(L, -2);
return 1; // The DecoderMethod wrapper.
}
// Unlike most of our exposed Lua functions, this does not correspond to an
// actual method on the underlying DecoderMethod. But it's convenient, and
// important to implement in C because we can do stack allocation and
// initialization of our runtime structures like the Decoder and Sink.
static int lupb_pbdecodermethod_parse(lua_State *L) {
size_t len;
const upb_pbdecodermethod *method = lupb_pbdecodermethod_check(L, 1);
const char *pb = lua_tolstring(L, 2, &len);
const upb_handlers *handlers = upb_pbdecodermethod_desthandlers(method);
lua_getuservalue(L, 1);
lua_rawgeti(L, -1, MSGDEF_INDEX);
lupb_assert(L, !lua_isnil(L, -1));
lupb_msg_pushnew(L, -1); // Push new message.
void *msg = lua_touserdata(L, -1);
// Handlers need this.
lua_getuservalue(L, -1);
upb_status status = UPB_STATUS_INIT;
upb_env env;
upb_env_init(&env);
upb_env_reporterrorsto(&env, &status);
upb_sink sink;
upb_sink_reset(&sink, handlers, msg);
upb_pbdecoder *decoder = upb_pbdecoder_create(&env, method, &sink);
upb_bufsrc_putbuf(pb, len, upb_pbdecoder_input(decoder));
// TODO: This won't get called in the error case, which longjmp's across us.
// This will cause the memory to leak. To remedy this, we should make the
// upb_env wrapped in a userdata that guarantees this will get called.
upb_env_uninit(&env);
lupb_checkstatus(L, &status);
lua_pop(L, 1); // Uservalue.
return 1;
}
static const struct luaL_Reg lupb_pbdecodermethod_m[] = {
{"parse", lupb_pbdecodermethod_parse},
{NULL, NULL}
};
static const struct luaL_Reg toplevel_m[] = {
{"DecoderMethod", lupb_pbdecodermethod_new},
{NULL, NULL}
};
int luaopen_upb_pb(lua_State *L) {
luaopen_upb(L);
static char module_key;
if (lupb_openlib(L, &module_key, "upb.pb", toplevel_m)) {
return 1;
}
lupb_register_type(L, LUPB_PBDECODERMETHOD, lupb_pbdecodermethod_m, NULL,
true);
return 1;
}
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