Added API for getting fielddef default as a upb_msgval.

BUILD

@@ -149,6 +149,7 @@ cc_library(
         "upb/def.h",
         "upb/def.hpp",
         "upb/reflection.h",
+        "upb/reflection.hpp",
     ],
     copts = UPB_DEFAULT_COPTS,
     visibility = ["//visibility:public"],

cmake/CMakeLists.txt

@@ -99,7 +99,8 @@ add_library(reflection
   ../upb/reflection.c
   ../upb/def.h
   ../upb/def.hpp
-  ../upb/reflection.h)
+  ../upb/reflection.h
+  ../upb/reflection.hpp)
 target_link_libraries(reflection
   descriptor_upb_proto
   port

tests/test_cpp.cc

@@ -977,6 +977,17 @@ void TestInlinedArena() {
   ASSERT(n == 0);
 }
 
+void TestDefault() {
+  upb::SymbolTable symtab;
+  upb::MessageDefPtr md(upb_test_TestMessage_getmsgdef(symtab.ptr()));
+  upb::FieldDefPtr i32_f = md.FindFieldByName("i32");
+  upb::FieldDefPtr str_f = md.FindFieldByName("str");
+  ASSERT(i32_f && str_f);
+  ASSERT(i32_f.default_value().int32_val == 5);
+  ASSERT(strcmp(str_f.default_value().str_val.data, "abc") == 0);
+  ASSERT(str_f.default_value().str_val.size == 3);
+}
+
 extern "C" {
 
 int run_tests() {
@@ -1014,6 +1025,7 @@ int run_tests() {
   TestHandlerDataDestruction();
   TestIteration();
   TestArena();
+  TestDefault();
 
   return 0;
 }

tests/test_cpp.proto

@@ -3,9 +3,9 @@ syntax = "proto2";
 package upb.test;
 
 message TestMessage {
-  optional int32 i32 = 1;
+  optional int32 i32 = 1 [default = 5];
   repeated int32 r_i32 = 2;
-  optional string str = 3;
+  optional string str = 3 [default = "abc"];
   repeated string r_str = 4;
   optional TestMessage msg = 5;
   repeated TestMessage r_msg = 6;

tests/test_generated_code.c

@@ -410,6 +410,40 @@ void test_status_truncation(void) {
   }
 }
 
+void decrement_int(void *ptr) {
+  int* iptr = ptr;
+  (*iptr)--;
+}
+
+void test_arena(void) {
+  int i1 = 5;
+  int i2 = 5;
+  int i3 = 5;
+  int i4 = 5;
+
+  upb_arena *arena1 = upb_arena_new();
+  upb_arena *arena2 = upb_arena_new();
+
+  upb_arena_addcleanup(arena1, &i1, decrement_int);
+  upb_arena_addcleanup(arena2, &i2, decrement_int);
+
+  upb_arena_fuse(arena1, arena2);
+
+  upb_arena_addcleanup(arena1, &i3, decrement_int);
+  upb_arena_addcleanup(arena2, &i4, decrement_int);
+
+  upb_arena_free(arena1);
+  ASSERT(i1 == 5);
+  ASSERT(i2 == 5);
+  ASSERT(i3 == 5);
+  ASSERT(i4 == 5);
+  upb_arena_free(arena2);
+  ASSERT(i1 == 4);
+  ASSERT(i2 == 4);
+  ASSERT(i3 == 4);
+  ASSERT(i4 == 4);
+}
+
 int run_tests(int argc, char *argv[]) {
   test_scalars();
   test_utf8();
@@ -419,5 +453,6 @@ int run_tests(int argc, char *argv[]) {
   test_repeated();
   test_null_decode_buf();
   test_status_truncation();
+  test_arena();
   return 0;
 }

upb/def.c

@@ -8,6 +8,9 @@
 #include <string.h>
 
 #include "google/protobuf/descriptor.upb.h"
+#include "upb/reflection.h"
+
+/* Must be last. */
 #include "upb/port_def.inc"
 
 typedef struct {
@@ -407,6 +410,23 @@ const upb_oneofdef *upb_fielddef_realcontainingoneof(const upb_fielddef *f) {
   return f->oneof;
 }
 
+upb_msgval upb_fielddef_default(const upb_fielddef *f) {
+  UPB_ASSERT(!upb_fielddef_issubmsg(f));
+  upb_msgval ret;
+  if (upb_fielddef_isstring(f)) {
+    str_t *str = f->defaultval.str;
+    if (str) {
+      ret.str_val.data = str->str;
+      ret.str_val.size = str->len;
+    } else {
+      ret.str_val.size = 0;
+    }
+  } else {
+    memcpy(&ret, &f->defaultval, 8);
+  }
+  return ret;
+}
+
 static void chkdefaulttype(const upb_fielddef *f, int ctype) {
   UPB_UNUSED(f);
   UPB_UNUSED(ctype);

upb/def.h

@@ -18,6 +18,7 @@
 #include "upb/table.int.h"
 #include "google/protobuf/descriptor.upb.h"
 
+/* Must be last. */
 #include "upb/port_def.inc"
 
 #ifdef __cplusplus

upb/def.hpp

@@ -8,10 +8,13 @@
 #include <vector>
 
 #include "upb/def.h"
+#include "upb/reflection.h"
 #include "upb/upb.hpp"
 
 namespace upb {
 
+typedef upb_msgval MessageValue;
+
 class EnumDefPtr;
 class MessageDefPtr;
 class OneofDefPtr;
@@ -106,6 +109,8 @@ class FieldDefPtr {
   float default_float() const { return upb_fielddef_defaultfloat(ptr_); }
   double default_double() const { return upb_fielddef_defaultdouble(ptr_); }
 
+  MessageValue default_value() const { return upb_fielddef_default(ptr_); }
+
   // The resulting string is always NULL-terminated.  If non-NULL, the length
   // will be stored in *len.
   const char* default_string(size_t* len) const {

upb/handlers.h

@@ -22,8 +22,6 @@
 #include "upb/def.h"
 #include "upb/table.int.h"
 
-#include "upb/port_def.inc"
-
 #ifdef __cplusplus
 #include "upb/def.hpp"
 namespace upb {
@@ -34,6 +32,8 @@ template <class T> struct CanonicalType;
 }  /* namespace upb */
 #endif
 
+/* Must be last. */
+#include "upb/port_def.inc"
 
 /* The maximum depth that the handler graph can have.  This is a resource limit
  * for the C stack since we sometimes need to recursively traverse the graph.

upb/reflection.h

@@ -8,6 +8,10 @@
 
 #include "upb/port_def.inc"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef union {
   bool bool_val;
   float float_val;
@@ -28,6 +32,8 @@ typedef union {
   upb_array* array;
 } upb_mutmsgval;
 
+upb_msgval upb_fielddef_default(const upb_fielddef *f);
+
 /** upb_msg *******************************************************************/
 
 /* Creates a new message of the given type in the given arena. */
@@ -163,6 +169,10 @@ upb_msgval upb_mapiter_value(const upb_map *map, size_t iter);
  * iterator must not have been initialized const. */
 void upb_mapiter_setvalue(upb_map *map, size_t iter, upb_msgval value);
 
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
 #include "upb/port_undef.inc"
 
 #endif /* UPB_REFLECTION_H_ */

upb/reflection.hpp

@@ -0,0 +1,13 @@
+
+#ifndef UPB_REFLECTION_HPP_
+#define UPB_REFLECTION_HPP_
+
+#include "upb/reflection.h"
+
+namespace upb {
+
+typedef upb_msgval MessageValue;
+
+}  // namespace upb
+
+#endif  // UPB_REFLECTION_HPP_