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Diffstat (limited to 'upb/bindings/lua/upb.pb.c')
-rw-r--r-- | upb/bindings/lua/upb.pb.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/upb/bindings/lua/upb.pb.c b/upb/bindings/lua/upb.pb.c new file mode 100644 index 0000000..c9f1f47 --- /dev/null +++ b/upb/bindings/lua/upb.pb.c @@ -0,0 +1,106 @@ +/* + * 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_pbdecoder decoder; + upb_status status = UPB_STATUS_INIT; + upb_pbdecoder_init(&decoder, method, &status); + upb_sink sink; + upb_sink_reset(&sink, handlers, msg); + upb_pbdecoder_resetoutput(&decoder, &sink); + upb_bufsrc_putbuf(pb, len, upb_pbdecoder_input(&decoder)); + // TODO: Our need to call uninit isn't longjmp-safe; what if the decode + // triggers a Lua error? uninit is only needed if the decoder + // dynamically-allocated a growing stack -- ditch this feature and live with + // the compile-time limit? Or have a custom allocation function that + // allocates Lua GC-rooted memory? + upb_pbdecoder_uninit(&decoder); + 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; +} |