Removed old-style C++ handlers that relied on UB in favor of more normal ones.

1 files changed, 478 insertions, 661 deletions

diff --git a/upb/def.h b/upb/def.h
index 81b5659..fb8a71d 100644
--- a/upb/def.h
+++ b/upb/def.h
@@ -2,11 +2,11 @@
 ** Defs are upb's internal representation of the constructs that can appear
 ** in a .proto file:
 **
-** - upb::MessageDef (upb_msgdef): describes a "message" construct.
-** - upb::FieldDef (upb_fielddef): describes a message field.
-** - upb::FileDef (upb_filedef): describes a .proto file and its defs.
-** - upb::EnumDef (upb_enumdef): describes an enum.
-** - upb::OneofDef (upb_oneofdef): describes a oneof.
+** - upb::MessageDefPtr (upb_msgdef): describes a "message" construct.
+** - upb::FieldDefPtr (upb_fielddef): describes a message field.
+** - upb::FileDefPtr (upb_filedef): describes a .proto file and its defs.
+** - upb::EnumDefPtr (upb_enumdef): describes an enum.
+** - upb::OneofDefPtr (upb_oneofdef): describes a oneof.
 **
 ** TODO: definitions of services.
 **
@@ -23,51 +23,101 @@
 
 #ifdef __cplusplus
 #include <cstring>
+#include <memory>
 #include <string>
 #include <vector>
 
 namespace upb {
-class EnumDef;
-class FieldDef;
-class FileDef;
-class MessageDef;
-class OneofDef;
+class EnumDefPtr;
+class FieldDefPtr;
+class FileDefPtr;
+class MessageDefPtr;
+class OneofDefPtr;
 class SymbolTable;
 }
 #endif
 
-UPB_DECLARE_TYPE(upb::EnumDef, upb_enumdef)
-UPB_DECLARE_TYPE(upb::FieldDef, upb_fielddef)
-UPB_DECLARE_TYPE(upb::FileDef, upb_filedef)
-UPB_DECLARE_TYPE(upb::MessageDef, upb_msgdef)
-UPB_DECLARE_TYPE(upb::OneofDef, upb_oneofdef)
-UPB_DECLARE_TYPE(upb::SymbolTable, upb_symtab)
-
-
-/* upb::FieldDef **************************************************************/
+struct upb_enumdef;
+typedef struct upb_enumdef upb_enumdef;
+struct upb_fielddef;
+typedef struct upb_fielddef upb_fielddef;
+struct upb_filedef;
+typedef struct upb_filedef upb_filedef;
+struct upb_msgdef;
+typedef struct upb_msgdef upb_msgdef;
+struct upb_oneofdef;
+typedef struct upb_oneofdef upb_oneofdef;
+struct upb_symtab;
+typedef struct upb_symtab upb_symtab;
+
+/* upb_fielddef ***************************************************************/
 
 /* Maximum field number allowed for FieldDefs.  This is an inherent limit of the
  * protobuf wire format. */
 #define UPB_MAX_FIELDNUMBER ((1 << 29) - 1)
 
+UPB_BEGIN_EXTERN_C
+
+const char *upb_fielddef_fullname(const upb_fielddef *f);
+upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f);
+upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f);
+upb_label_t upb_fielddef_label(const upb_fielddef *f);
+uint32_t upb_fielddef_number(const upb_fielddef *f);
+const char *upb_fielddef_name(const upb_fielddef *f);
+bool upb_fielddef_isextension(const upb_fielddef *f);
+bool upb_fielddef_lazy(const upb_fielddef *f);
+bool upb_fielddef_packed(const upb_fielddef *f);
+size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len);
+const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f);
+const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f);
+upb_msgdef *upb_fielddef_containingtype_mutable(upb_fielddef *f);
+uint32_t upb_fielddef_index(const upb_fielddef *f);
+bool upb_fielddef_issubmsg(const upb_fielddef *f);
+bool upb_fielddef_isstring(const upb_fielddef *f);
+bool upb_fielddef_isseq(const upb_fielddef *f);
+bool upb_fielddef_isprimitive(const upb_fielddef *f);
+bool upb_fielddef_ismap(const upb_fielddef *f);
+int64_t upb_fielddef_defaultint64(const upb_fielddef *f);
+int32_t upb_fielddef_defaultint32(const upb_fielddef *f);
+uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f);
+uint32_t upb_fielddef_defaultuint32(const upb_fielddef *f);
+bool upb_fielddef_defaultbool(const upb_fielddef *f);
+float upb_fielddef_defaultfloat(const upb_fielddef *f);
+double upb_fielddef_defaultdouble(const upb_fielddef *f);
+const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len);
+bool upb_fielddef_hassubdef(const upb_fielddef *f);
+bool upb_fielddef_haspresence(const upb_fielddef *f);
+const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f);
+const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f);
+
+/* Internal only. */
+uint32_t upb_fielddef_selectorbase(const upb_fielddef *f);
+
+UPB_END_EXTERN_C
+
 #ifdef __cplusplus
 
 /* A upb_fielddef describes a single field in a message.  It is most often
  * found as a part of a upb_msgdef, but can also stand alone to represent
  * an extension. */
-class upb::FieldDef {
+class upb::FieldDefPtr {
  public:
+  explicit FieldDefPtr(const upb_fielddef *ptr) : ptr_(ptr) {}
+
+  const upb_fielddef* ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
+
   typedef upb_fieldtype_t Type;
   typedef upb_label_t Label;
   typedef upb_descriptortype_t DescriptorType;
 
-  const char* full_name() const;
+  const char* full_name() const { return upb_fielddef_fullname(ptr_); }
 
-  Type type() const;
-  Label label() const;
-  const char* name() const;
-  uint32_t number() const;
-  bool is_extension() const;
+  Type type() const { return upb_fielddef_type(ptr_); }
+  Label label() const { return upb_fielddef_label(ptr_); }
+  const char* name() const { return upb_fielddef_name(ptr_); }
+  uint32_t number() const { return upb_fielddef_number(ptr_); }
+  bool is_extension() const { return upb_fielddef_isextension(ptr_); }
 
   /* Copies the JSON name for this field into the given buffer.  Returns the
    * actual size of the JSON name, including the NULL terminator.  If the
@@ -79,7 +129,9 @@ class upb::FieldDef {
    * name.  However if the regular name is unset, the JSON name will be unset
    * also.
    */
-  size_t GetJsonName(char* buf, size_t len) const;
+  size_t GetJsonName(char *buf, size_t len) const {
+    return upb_fielddef_getjsonname(ptr_, buf, len);
+  }
 
   /* Convenience version of the above function which copies the JSON name
    * into the given string, returning false if the name is not set. */
@@ -97,20 +149,20 @@ class upb::FieldDef {
    * TODO(haberman): I think we want to move this into a FieldOptions container
    * when we add support for custom options (the FieldOptions struct will
    * contain both regular FieldOptions like "lazy" *and* custom options). */
-  bool lazy() const;
+  bool lazy() const { return upb_fielddef_lazy(ptr_); }
 
   /* For non-string, non-submessage fields, this indicates whether binary
    * protobufs are encoded in packed or non-packed format.
    *
    * TODO(haberman): see note above about putting options like this into a
    * FieldOptions container. */
-  bool packed() const;
+  bool packed() const { return upb_fielddef_packed(ptr_); }
 
   /* An integer that can be used as an index into an array of fields for
    * whatever message this field belongs to.  Guaranteed to be less than
    * f->containing_type()->field_count().  May only be accessed once the def has
    * been finalized. */
-  uint32_t index() const;
+  uint32_t index() const { return upb_fielddef_index(ptr_); }
 
   /* The MessageDef to which this field belongs.
    *
@@ -120,25 +172,27 @@ class upb::FieldDef {
    * If the field has not yet been added to a MessageDef, you can set the name
    * of the containing type symbolically instead.  This is mostly useful for
    * extensions, where the extension is declared separately from the message. */
-  const MessageDef* containing_type() const;
+  MessageDefPtr containing_type() const;
 
   /* The OneofDef to which this field belongs, or NULL if this field is not part
    * of a oneof. */
-  const OneofDef* containing_oneof() const;
+  OneofDefPtr containing_oneof() const;
 
   /* The field's type according to the enum in descriptor.proto.  This is not
    * the same as UPB_TYPE_*, because it distinguishes between (for example)
    * INT32 and SINT32, whereas our "type" enum does not.  This return of
    * descriptor_type() is a function of type(), integer_format(), and
    * is_tag_delimited().  */
-  DescriptorType descriptor_type() const;
+  DescriptorType descriptor_type() const {
+    return upb_fielddef_descriptortype(ptr_);
+  }
 
   /* Convenient field type tests. */
-  bool IsSubMessage() const;
-  bool IsString() const;
-  bool IsSequence() const;
-  bool IsPrimitive() const;
-  bool IsMap() const;
+  bool IsSubMessage() const { return upb_fielddef_issubmsg(ptr_); }
+  bool IsString() const { return upb_fielddef_isstring(ptr_); }
+  bool IsSequence() const { return upb_fielddef_isseq(ptr_); }
+  bool IsPrimitive() const { return upb_fielddef_isprimitive(ptr_); }
+  bool IsMap() const { return upb_fielddef_ismap(ptr_); }
 
   /* Returns the non-string default value for this fielddef, which may either
    * be something the client set explicitly or the "default default" (0 for
@@ -146,210 +200,170 @@ class upb::FieldDef {
    * returned value, except for enum fields that are still mutable.
    *
    * Requires that the given function matches the field's current type. */
-  int64_t default_int64() const;
-  int32_t default_int32() const;
-  uint64_t default_uint64() const;
-  uint32_t default_uint32() const;
-  bool default_bool() const;
-  float default_float() const;
-  double default_double() const;
+  int64_t default_int64() const { return upb_fielddef_defaultint64(ptr_); }
+  int32_t default_int32() const { return upb_fielddef_defaultint32(ptr_); }
+  uint64_t default_uint64() const { return upb_fielddef_defaultuint64(ptr_); }
+  uint32_t default_uint32() const { return upb_fielddef_defaultuint32(ptr_); }
+  bool default_bool() const { return upb_fielddef_defaultbool(ptr_); }
+  float default_float() const { return upb_fielddef_defaultfloat(ptr_); }
+  double default_double() const { return upb_fielddef_defaultdouble(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;
+  const char *default_string(size_t * len) const {
+    return upb_fielddef_defaultstr(ptr_, len);
+  }
 
   /* Returns the enum or submessage def for this field, if any.  The field's
    * type must match (ie. you may only call enum_subdef() for fields where
    * type() == UPB_TYPE_ENUM). */
-  const EnumDef* enum_subdef() const;
-  const MessageDef* message_subdef() const;
+  EnumDefPtr enum_subdef() const;
+  MessageDefPtr message_subdef() const;
 
  private:
-  UPB_DISALLOW_POD_OPS(FieldDef, upb::FieldDef)
+  const upb_fielddef *ptr_;
 };
 
-# endif  /* defined(__cplusplus) */
-
-UPB_BEGIN_EXTERN_C
-
-/* Native C API. */
-const char *upb_fielddef_fullname(const upb_fielddef *f);
-bool upb_fielddef_typeisset(const upb_fielddef *f);
-upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f);
-upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f);
-upb_label_t upb_fielddef_label(const upb_fielddef *f);
-uint32_t upb_fielddef_number(const upb_fielddef *f);
-const char *upb_fielddef_name(const upb_fielddef *f);
-bool upb_fielddef_isextension(const upb_fielddef *f);
-bool upb_fielddef_lazy(const upb_fielddef *f);
-bool upb_fielddef_packed(const upb_fielddef *f);
-size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len);
-const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f);
-const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f);
-upb_msgdef *upb_fielddef_containingtype_mutable(upb_fielddef *f);
-uint32_t upb_fielddef_index(const upb_fielddef *f);
-bool upb_fielddef_issubmsg(const upb_fielddef *f);
-bool upb_fielddef_isstring(const upb_fielddef *f);
-bool upb_fielddef_isseq(const upb_fielddef *f);
-bool upb_fielddef_isprimitive(const upb_fielddef *f);
-bool upb_fielddef_ismap(const upb_fielddef *f);
-int64_t upb_fielddef_defaultint64(const upb_fielddef *f);
-int32_t upb_fielddef_defaultint32(const upb_fielddef *f);
-uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f);
-uint32_t upb_fielddef_defaultuint32(const upb_fielddef *f);
-bool upb_fielddef_defaultbool(const upb_fielddef *f);
-float upb_fielddef_defaultfloat(const upb_fielddef *f);
-double upb_fielddef_defaultdouble(const upb_fielddef *f);
-const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len);
-bool upb_fielddef_hassubdef(const upb_fielddef *f);
-bool upb_fielddef_haspresence(const upb_fielddef *f);
-const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f);
-const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f);
-
-/* Internal only. */
-uint32_t upb_fielddef_selectorbase(const upb_fielddef *f);
-
-UPB_END_EXTERN_C
+#endif  /* __cplusplus */
 
+/* upb_oneofdef ***************************************************************/
 
-/* upb::MessageDef ************************************************************/
+UPB_BEGIN_EXTERN_C
 
-typedef upb_inttable_iter upb_msg_field_iter;
-typedef upb_strtable_iter upb_msg_oneof_iter;
+typedef upb_inttable_iter upb_oneof_iter;
 
-/* Well-known field tag numbers for map-entry messages. */
-#define UPB_MAPENTRY_KEY   1
-#define UPB_MAPENTRY_VALUE 2
+const char *upb_oneofdef_name(const upb_oneofdef *o);
+const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o);
+int upb_oneofdef_numfields(const upb_oneofdef *o);
+uint32_t upb_oneofdef_index(const upb_oneofdef *o);
 
-/* Well-known field tag numbers for Any messages. */
-#define UPB_ANY_TYPE 1
-#define UPB_ANY_VALUE 2
+/* Oneof lookups:
+ * - ntof:  look up a field by name.
+ * - ntofz: look up a field by name (as a null-terminated string).
+ * - itof:  look up a field by number. */
+const upb_fielddef *upb_oneofdef_ntof(const upb_oneofdef *o,
+                                      const char *name, size_t length);
+UPB_INLINE const upb_fielddef *upb_oneofdef_ntofz(const upb_oneofdef *o,
+                                                  const char *name) {
+  return upb_oneofdef_ntof(o, name, strlen(name));
+}
+const upb_fielddef *upb_oneofdef_itof(const upb_oneofdef *o, uint32_t num);
 
-/* Well-known field tag numbers for timestamp messages. */
-#define UPB_DURATION_SECONDS 1
-#define UPB_DURATION_NANOS 2
+/*  upb_oneof_iter i;
+ *  for(upb_oneof_begin(&i, e); !upb_oneof_done(&i); upb_oneof_next(&i)) {
+ *    // ...
+ *  }
+ */
+void upb_oneof_begin(upb_oneof_iter *iter, const upb_oneofdef *o);
+void upb_oneof_next(upb_oneof_iter *iter);
+bool upb_oneof_done(upb_oneof_iter *iter);
+upb_fielddef *upb_oneof_iter_field(const upb_oneof_iter *iter);
+void upb_oneof_iter_setdone(upb_oneof_iter *iter);
+bool upb_oneof_iter_isequal(const upb_oneof_iter *iter1,
+                            const upb_oneof_iter *iter2);
 
-/* Well-known field tag numbers for duration messages. */
-#define UPB_TIMESTAMP_SECONDS 1
-#define UPB_TIMESTAMP_NANOS 2
+UPB_END_EXTERN_C
 
 #ifdef __cplusplus
 
-/* Structure that describes a single .proto message type. */
-class upb::MessageDef {
+/* Class that represents a oneof. */
+class upb::OneofDefPtr {
  public:
-  const char* full_name() const;
-  const char* name() const;
+  explicit OneofDefPtr(const upb_oneofdef *ptr) : ptr_(ptr) {}
 
-  /* The number of fields that belong to the MessageDef. */
-  int field_count() const;
-
-  /* The number of oneofs that belong to the MessageDef. */
-  int oneof_count() const;
+  const upb_oneofdef* ptr() const { return ptr_; }
+  explicit operator bool() { return ptr_ != nullptr; }
 
-  upb_syntax_t syntax() const;
+  /* Returns the MessageDef that owns this OneofDef. */
+  MessageDefPtr containing_type() const;
 
-  /* These return NULL if the field is not found. */
-  const FieldDef* FindFieldByNumber(uint32_t number) const;
-  const FieldDef* FindFieldByName(const char* name, size_t len) const;
+  /* Returns the name of this oneof. This is the name used to look up the oneof
+   * by name once added to a message def. */
+  const char* name() const { return upb_oneofdef_name(ptr_); }
 
+  /* Returns the number of fields currently defined in the oneof. */
+  int field_count() const { return upb_oneofdef_numfields(ptr_); }
 
-  const FieldDef* FindFieldByName(const char *name) const {
-    return FindFieldByName(name, strlen(name));
+  /* Looks up by name. */
+  FieldDefPtr FindFieldByName(const char *name, size_t len) const {
+    return FieldDefPtr(upb_oneofdef_ntof(ptr_, name, len));
+  }
+  FieldDefPtr FindFieldByName(const char* name) const {
+    return FieldDefPtr(upb_oneofdef_ntofz(ptr_, name));
   }
 
   template <class T>
-  const FieldDef* FindFieldByName(const T& str) const {
+  FieldDefPtr FindFieldByName(const T& str) const {
     return FindFieldByName(str.c_str(), str.size());
   }
 
-  OneofDef* FindOneofByName(const char* name, size_t len);
-  const OneofDef* FindOneofByName(const char* name, size_t len) const;
-
-  const OneofDef* FindOneofByName(const char* name) const {
-    return FindOneofByName(name, strlen(name));
-  }
-
-  template<class T>
-  const OneofDef* FindOneofByName(const T& str) const {
-    return FindOneofByName(str.c_str(), str.size());
+  /* Looks up by tag number. */
+  FieldDefPtr FindFieldByNumber(uint32_t num) const {
+    return FieldDefPtr(upb_oneofdef_itof(ptr_, num));
   }
 
-  /* Is this message a map entry? */
-  void setmapentry(bool map_entry);
-  bool mapentry() const;
-
-  /* Return the type of well known type message. UPB_WELLKNOWN_UNSPECIFIED for
-   * non-well-known message. */
-  upb_wellknowntype_t wellknowntype() const;
+  class const_iterator
+      : public std::iterator<std::forward_iterator_tag, FieldDefPtr> {
+   public:
+    void operator++() { upb_oneof_next(&iter_); }
 
-  /* Whether is a number wrapper. */
-  bool isnumberwrapper() const;
+    FieldDefPtr operator*() const {
+      return FieldDefPtr(upb_oneof_iter_field(&iter_));
+    }
 
-  /* Iteration over fields.  The order is undefined. */
-  class const_field_iterator
-      : public std::iterator<std::forward_iterator_tag, const FieldDef*> {
-   public:
-    explicit const_field_iterator(const MessageDef* md);
-    static const_field_iterator end(const MessageDef* md);
+    bool operator!=(const const_iterator& other) const {
+      return !upb_oneof_iter_isequal(&iter_, &other.iter_);
+    }
 
-    void operator++();
-    const FieldDef* operator*() const;
-    bool operator!=(const const_field_iterator& other) const;
-    bool operator==(const const_field_iterator& other) const;
+    bool operator==(const const_iterator& other) const {
+      return upb_oneof_iter_isequal(&iter_, &other.iter_);
+    }
 
    private:
-    upb_msg_field_iter iter_;
-  };
+    friend class OneofDefPtr;
+
+    const_iterator() {}
+    explicit const_iterator(OneofDefPtr o) {
+      upb_oneof_begin(&iter_, o.ptr());
+    }
+    static const_iterator end() {
+      const_iterator iter;
+      upb_oneof_iter_setdone(&iter.iter_);
+      return iter;
+    }
 
-  /* Iteration over oneofs. The order is undefined. */
-  class const_oneof_iterator
-      : public std::iterator<std::forward_iterator_tag, const FieldDef*> {
-   public:
-    explicit const_oneof_iterator(const MessageDef* md);
-    static const_oneof_iterator end(const MessageDef* md);
+    upb_oneof_iter iter_;
+  };
 
-    void operator++();
-    const OneofDef* operator*() const;
-    bool operator!=(const const_oneof_iterator& other) const;
-    bool operator==(const const_oneof_iterator& other) const;
+  const_iterator begin() const { return const_iterator(*this); }
+  const_iterator end() const { return const_iterator::end(); }
 
-   private:
-    upb_msg_oneof_iter iter_;
-  };
+ private:
+  const upb_oneofdef *ptr_;
+};
 
-  class ConstFieldAccessor {
-   public:
-    explicit ConstFieldAccessor(const MessageDef* msg) : msg_(msg) {}
-    const_field_iterator begin() { return msg_->field_begin(); }
-    const_field_iterator end() { return msg_->field_end(); }
-   private:
-    const MessageDef* msg_;
-  };
+#endif  /* __cplusplus */
 
-  class ConstOneofAccessor {
-   public:
-    explicit ConstOneofAccessor(const MessageDef* msg) : msg_(msg) {}
-    const_oneof_iterator begin() { return msg_->oneof_begin(); }
-    const_oneof_iterator end() { return msg_->oneof_end(); }
-   private:
-    const MessageDef* msg_;
-  };
+/* upb_msgdef *****************************************************************/
 
-  const_field_iterator field_begin() const;
-  const_field_iterator field_end() const;
+typedef upb_inttable_iter upb_msg_field_iter;
+typedef upb_strtable_iter upb_msg_oneof_iter;
 
-  const_oneof_iterator oneof_begin() const;
-  const_oneof_iterator oneof_end() const;
+/* Well-known field tag numbers for map-entry messages. */
+#define UPB_MAPENTRY_KEY   1
+#define UPB_MAPENTRY_VALUE 2
 
-  ConstFieldAccessor fields() const { return ConstFieldAccessor(this); }
-  ConstOneofAccessor oneofs() const { return ConstOneofAccessor(this); }
+/* Well-known field tag numbers for Any messages. */
+#define UPB_ANY_TYPE 1
+#define UPB_ANY_VALUE 2
 
- private:
-  UPB_DISALLOW_POD_OPS(MessageDef, upb::MessageDef)
-};
+/* Well-known field tag numbers for timestamp messages. */
+#define UPB_DURATION_SECONDS 1
+#define UPB_DURATION_NANOS 2
 
-#endif  /* __cplusplus */
+/* Well-known field tag numbers for duration messages. */
+#define UPB_TIMESTAMP_SECONDS 1
+#define UPB_TIMESTAMP_NANOS 2
 
 UPB_BEGIN_EXTERN_C
 
@@ -362,30 +376,12 @@ bool upb_msgdef_mapentry(const upb_msgdef *m);
 upb_wellknowntype_t upb_msgdef_wellknowntype(const upb_msgdef *m);
 bool upb_msgdef_isnumberwrapper(const upb_msgdef *m);
 bool upb_msgdef_setsyntax(upb_msgdef *m, upb_syntax_t syntax);
-
-/* Internal-only. */
-size_t upb_msgdef_selectorcount(const upb_msgdef *m);
-uint32_t upb_msgdef_submsgfieldcount(const upb_msgdef *m);
-
-/* Field lookup in a couple of different variations:
- *   - itof = int to field
- *   - ntof = name to field
- *   - ntofz = name to field, null-terminated string. */
 const upb_fielddef *upb_msgdef_itof(const upb_msgdef *m, uint32_t i);
 const upb_fielddef *upb_msgdef_ntof(const upb_msgdef *m, const char *name,
                                     size_t len);
-int upb_msgdef_numfields(const upb_msgdef *m);
-
-UPB_INLINE const upb_fielddef *upb_msgdef_ntofz(const upb_msgdef *m,
-                                                const char *name) {
-  return upb_msgdef_ntof(m, name, strlen(name));
-}
-
-/* Oneof lookup:
- *   - ntoo = name to oneof
- *   - ntooz = name to oneof, null-terminated string. */
 const upb_oneofdef *upb_msgdef_ntoo(const upb_msgdef *m, const char *name,
                                     size_t len);
+int upb_msgdef_numfields(const upb_msgdef *m);
 int upb_msgdef_numoneofs(const upb_msgdef *m);
 
 UPB_INLINE const upb_oneofdef *upb_msgdef_ntooz(const upb_msgdef *m,
@@ -393,6 +389,15 @@ UPB_INLINE const upb_oneofdef *upb_msgdef_ntooz(const upb_msgdef *m,
   return upb_msgdef_ntoo(m, name, strlen(name));
 }
 
+UPB_INLINE const upb_fielddef *upb_msgdef_ntofz(const upb_msgdef *m,
+                                                const char *name) {
+  return upb_msgdef_ntof(m, name, strlen(name));
+}
+
+/* Internal-only. */
+size_t upb_msgdef_selectorcount(const upb_msgdef *m);
+uint32_t upb_msgdef_submsgfieldcount(const upb_msgdef *m);
+
 /* Lookup of either field or oneof by name.  Returns whether either was found.
  * If the return is true, then the found def will be set, and the non-found
  * one set to NULL. */
@@ -423,71 +428,198 @@ void upb_msg_field_next(upb_msg_field_iter *iter);
 bool upb_msg_field_done(const upb_msg_field_iter *iter);
 upb_fielddef *upb_msg_iter_field(const upb_msg_field_iter *iter);
 void upb_msg_field_iter_setdone(upb_msg_field_iter *iter);
+bool upb_msg_field_iter_isequal(const upb_msg_field_iter * iter1,
+                                const upb_msg_field_iter * iter2);
 
 /* Similar to above, we also support iterating through the oneofs in a
  * msgdef. */
-void upb_msg_oneof_begin(upb_msg_oneof_iter *iter, const upb_msgdef *m);
-void upb_msg_oneof_next(upb_msg_oneof_iter *iter);
+void upb_msg_oneof_begin(upb_msg_oneof_iter * iter, const upb_msgdef *m);
+void upb_msg_oneof_next(upb_msg_oneof_iter * iter);
 bool upb_msg_oneof_done(const upb_msg_oneof_iter *iter);
 const upb_oneofdef *upb_msg_iter_oneof(const upb_msg_oneof_iter *iter);
-void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter *iter);
+void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter * iter);
+bool upb_msg_oneof_iter_isequal(const upb_msg_oneof_iter *iter1,
+                                const upb_msg_oneof_iter *iter2);
 
 UPB_END_EXTERN_C
 
+#ifdef __cplusplus
 
-/* upb::EnumDef ***************************************************************/
+/* Structure that describes a single .proto message type. */
+class upb::MessageDefPtr {
+ public:
+  MessageDefPtr(const upb_msgdef *ptr) : ptr_(ptr) {}
 
-typedef upb_strtable_iter upb_enum_iter;
+  const upb_msgdef *ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
 
-#ifdef __cplusplus
+  const char* full_name() const { return upb_msgdef_fullname(ptr_); }
+  const char* name() const { return upb_msgdef_name(ptr_); }
 
-class upb::EnumDef {
- public:
-  const char* full_name() const;
-  const char* name() const;
-  /* The value that is used as the default when no field default is specified.
-   * If not set explicitly, the first value that was added will be used.
-   * The default value must be a member of the enum.
-   * Requires that value_count() > 0. */
-  int32_t default_value() const;
+  /* The number of fields that belong to the MessageDef. */
+  int field_count() const { return upb_msgdef_numfields(ptr_); }
 
-  /* Returns the number of values currently defined in the enum.  Note that
-   * multiple names can refer to the same number, so this may be greater than
-   * the total number of unique numbers. */
-  int value_count() const;
+  /* The number of oneofs that belong to the MessageDef. */
+  int oneof_count() const { return upb_msgdef_numoneofs(ptr_); }
 
-  /* Lookups from name to integer, returning true if found. */
-  bool FindValueByName(const char* name, int32_t* num) const;
+  upb_syntax_t syntax() const { return upb_msgdef_syntax(ptr_); }
 
-  /* Finds the name corresponding to the given number, or NULL if none was
-   * found.  If more than one name corresponds to this number, returns the
-   * first one that was added. */
-  const char* FindValueByNumber(int32_t num) const;
+  /* These return null pointers if the field is not found. */
+  FieldDefPtr FindFieldByNumber(uint32_t number) const {
+    return FieldDefPtr(upb_msgdef_itof(ptr_, number));
+  }
+  FieldDefPtr FindFieldByName(const char* name, size_t len) const {
+    return FieldDefPtr(upb_msgdef_ntof(ptr_, name, len));
+  }
+  FieldDefPtr FindFieldByName(const char *name) const {
+    return FieldDefPtr(upb_msgdef_ntofz(ptr_, name));
+  }
 
-  /* Iteration over name/value pairs.  The order is undefined.
-   * Adding an enum val invalidates any iterators.
-   *
-   * TODO: make compatible with range-for, with elements as pairs? */
-  class Iterator {
+  template <class T>
+  FieldDefPtr FindFieldByName(const T& str) const {
+    return FindFieldByName(str.c_str(), str.size());
+  }
+
+  OneofDefPtr FindOneofByName(const char* name, size_t len) const {
+    return OneofDefPtr(upb_msgdef_ntoo(ptr_, name, len));
+  }
+
+  OneofDefPtr FindOneofByName(const char *name) const {
+    return OneofDefPtr(upb_msgdef_ntooz(ptr_, name));
+  }
+
+  template <class T>
+  OneofDefPtr FindOneofByName(const T &str) const {
+    return FindOneofByName(str.c_str(), str.size());
+  }
+
+  /* Is this message a map entry? */
+  bool mapentry() const { return upb_msgdef_mapentry(ptr_); }
+
+  /* Return the type of well known type message. UPB_WELLKNOWN_UNSPECIFIED for
+   * non-well-known message. */
+  upb_wellknowntype_t wellknowntype() const {
+    return upb_msgdef_wellknowntype(ptr_);
+  }
+
+  /* Whether is a number wrapper. */
+  bool isnumberwrapper() const { return upb_msgdef_isnumberwrapper(ptr_); }
+
+  /* Iteration over fields.  The order is undefined. */
+  class const_field_iterator
+      : public std::iterator<std::forward_iterator_tag, FieldDefPtr> {
    public:
-    explicit Iterator(const EnumDef*);
+    void operator++() { upb_msg_field_next(&iter_); }
+
+    FieldDefPtr operator*() const {
+      return FieldDefPtr(upb_msg_iter_field(&iter_));
+    }
 
-    int32_t number();
-    const char *name();
-    bool Done();
-    void Next();
+    bool operator!=(const const_field_iterator &other) const {
+      return !upb_msg_field_iter_isequal(&iter_, &other.iter_);
+    }
+
+    bool operator==(const const_field_iterator &other) const {
+      return upb_msg_field_iter_isequal(&iter_, &other.iter_);
+    }
 
    private:
-    upb_enum_iter iter_;
+    friend class MessageDefPtr;
+
+    explicit const_field_iterator() {}
+
+    explicit const_field_iterator(MessageDefPtr msg) {
+      upb_msg_field_begin(&iter_, msg.ptr());
+    }
+
+    static const_field_iterator end() {
+      const_field_iterator iter;
+      upb_msg_field_iter_setdone(&iter.iter_);
+      return iter;
+    }
+
+    upb_msg_field_iter iter_;
+  };
+
+  /* Iteration over oneofs. The order is undefined. */
+  class const_oneof_iterator
+      : public std::iterator<std::forward_iterator_tag, OneofDefPtr> {
+   public:
+
+    void operator++() { upb_msg_oneof_next(&iter_); }
+
+    OneofDefPtr operator*() const {
+      return OneofDefPtr(upb_msg_iter_oneof(&iter_));
+    }
+
+    bool operator!=(const const_oneof_iterator& other) const {
+      return !upb_msg_oneof_iter_isequal(&iter_, &other.iter_);
+    }
+
+    bool operator==(const const_oneof_iterator &other) const {
+      return upb_msg_oneof_iter_isequal(&iter_, &other.iter_);
+    }
+
+   private:
+    friend class MessageDefPtr;
+
+    const_oneof_iterator() {}
+
+    explicit const_oneof_iterator(MessageDefPtr msg) {
+      upb_msg_oneof_begin(&iter_, msg.ptr());
+    }
+
+    static const_oneof_iterator end() {
+      const_oneof_iterator iter;
+      upb_msg_oneof_iter_setdone(&iter.iter_);
+      return iter;
+    }
+
+    upb_msg_oneof_iter iter_;
   };
 
+  class ConstFieldAccessor {
+   public:
+    explicit ConstFieldAccessor(const upb_msgdef* md) : md_(md) {}
+    const_field_iterator begin() { return MessageDefPtr(md_).field_begin(); }
+    const_field_iterator end() { return MessageDefPtr(md_).field_end(); }
+   private:
+    const upb_msgdef* md_;
+  };
+
+  class ConstOneofAccessor {
+   public:
+    explicit ConstOneofAccessor(const upb_msgdef* md) : md_(md) {}
+    const_oneof_iterator begin() { return MessageDefPtr(md_).oneof_begin(); }
+    const_oneof_iterator end() { return MessageDefPtr(md_).oneof_end(); }
+   private:
+    const upb_msgdef* md_;
+  };
+
+  const_field_iterator field_begin() const {
+    return const_field_iterator(*this);
+  }
+
+  const_field_iterator field_end() const { return const_field_iterator::end(); }
+
+  const_oneof_iterator oneof_begin() const {
+    return const_oneof_iterator(*this);
+  }
+
+  const_oneof_iterator oneof_end() const { return const_oneof_iterator::end(); }
+
+  ConstFieldAccessor fields() const { return ConstFieldAccessor(ptr()); }
+  ConstOneofAccessor oneofs() const { return ConstOneofAccessor(ptr()); }
+
  private:
-  UPB_DISALLOW_POD_OPS(EnumDef, upb::EnumDef)
+  const upb_msgdef* ptr_;
 };
 
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
+/* upb_enumdef ****************************************************************/
+
+typedef upb_strtable_iter upb_enum_iter;
 
 const char *upb_enumdef_fullname(const upb_enumdef *e);
 const char *upb_enumdef_name(const upb_enumdef *e);
@@ -519,188 +651,129 @@ bool upb_enum_done(upb_enum_iter *iter);
 const char *upb_enum_iter_name(upb_enum_iter *iter);
 int32_t upb_enum_iter_number(upb_enum_iter *iter);
 
-UPB_END_EXTERN_C
-
-
-/* upb::OneofDef **************************************************************/
-
-typedef upb_inttable_iter upb_oneof_iter;
-
 #ifdef __cplusplus
 
-/* Class that represents a oneof. */
-class upb::OneofDef {
+class upb::EnumDefPtr {
  public:
-  /* Returns the MessageDef that owns this OneofDef. */
-  const MessageDef* containing_type() const;
+  explicit EnumDefPtr(const upb_enumdef* ptr) : ptr_(ptr) {}
 
-  /* Returns the name of this oneof. This is the name used to look up the oneof
-   * by name once added to a message def. */
-  const char* name() const;
+  const upb_enumdef* ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
 
-  /* Returns the number of fields currently defined in the oneof. */
-  int field_count() const;
+  const char* full_name() const { return upb_enumdef_fullname(ptr_); }
+  const char* name() const { return upb_enumdef_name(ptr_); }
 
-  /* Looks up by name. */
-  const FieldDef* FindFieldByName(const char* name, size_t len) const;
-  FieldDef* FindFieldByName(const char* name, size_t len);
-  const FieldDef* FindFieldByName(const char* name) const {
-    return FindFieldByName(name, strlen(name));
-  }
+  /* The value that is used as the default when no field default is specified.
+   * If not set explicitly, the first value that was added will be used.
+   * The default value must be a member of the enum.
+   * Requires that value_count() > 0. */
+  int32_t default_value() const { return upb_enumdef_default(ptr_); }
 
-  template <class T>
-  const FieldDef* FindFieldByName(const T& str) const {
-    return FindFieldByName(str.c_str(), str.size());
+  /* Returns the number of values currently defined in the enum.  Note that
+   * multiple names can refer to the same number, so this may be greater than
+   * the total number of unique numbers. */
+  int value_count() const { return upb_enumdef_numvals(ptr_); }
+
+  /* Lookups from name to integer, returning true if found. */
+  bool FindValueByName(const char *name, int32_t *num) const {
+    return upb_enumdef_ntoiz(ptr_, name, num);
   }
 
-  /* Looks up by tag number. */
-  const FieldDef* FindFieldByNumber(uint32_t num) const;
+  /* Finds the name corresponding to the given number, or NULL if none was
+   * found.  If more than one name corresponds to this number, returns the
+   * first one that was added. */
+  const char *FindValueByNumber(int32_t num) const {
+    return upb_enumdef_iton(ptr_, num);
+  }
 
-  class const_iterator
-      : public std::iterator<std::forward_iterator_tag, const FieldDef*> {
+  /* Iteration over name/value pairs.  The order is undefined.
+   * Adding an enum val invalidates any iterators.
+   *
+   * TODO: make compatible with range-for, with elements as pairs? */
+  class Iterator {
    public:
-    explicit const_iterator(const OneofDef* md);
-    static const_iterator end(const OneofDef* md);
+    explicit Iterator(EnumDefPtr e) { upb_enum_begin(&iter_, e.ptr()); }
 
-    void operator++();
-    const FieldDef* operator*() const;
-    bool operator!=(const const_iterator& other) const;
-    bool operator==(const const_iterator& other) const;
+    int32_t number() { return upb_enum_iter_number(&iter_); }
+    const char *name() { return upb_enum_iter_name(&iter_); }
+    bool Done() { return upb_enum_done(&iter_); }
+    void Next() { return upb_enum_next(&iter_); }
 
    private:
-    upb_oneof_iter iter_;
+    upb_enum_iter iter_;
   };
 
-  const_iterator begin() const;
-  const_iterator end() const;
-
  private:
-  UPB_DISALLOW_POD_OPS(OneofDef, upb::OneofDef)
+  const upb_enumdef *ptr_;
 };
 
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
-
-const char *upb_oneofdef_name(const upb_oneofdef *o);
-const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o);
-int upb_oneofdef_numfields(const upb_oneofdef *o);
-uint32_t upb_oneofdef_index(const upb_oneofdef *o);
+/* upb_filedef ****************************************************************/
 
-/* Oneof lookups:
- * - ntof:  look up a field by name.
- * - ntofz: look up a field by name (as a null-terminated string).
- * - itof:  look up a field by number. */
-const upb_fielddef *upb_oneofdef_ntof(const upb_oneofdef *o,
-                                      const char *name, size_t length);
-UPB_INLINE const upb_fielddef *upb_oneofdef_ntofz(const upb_oneofdef *o,
-                                                  const char *name) {
-  return upb_oneofdef_ntof(o, name, strlen(name));
-}
-const upb_fielddef *upb_oneofdef_itof(const upb_oneofdef *o, uint32_t num);
+UPB_BEGIN_EXTERN_C
 
-/*  upb_oneof_iter i;
- *  for(upb_oneof_begin(&i, e); !upb_oneof_done(&i); upb_oneof_next(&i)) {
- *    // ...
- *  }
- */
-void upb_oneof_begin(upb_oneof_iter *iter, const upb_oneofdef *o);
-void upb_oneof_next(upb_oneof_iter *iter);
-bool upb_oneof_done(upb_oneof_iter *iter);
-upb_fielddef *upb_oneof_iter_field(const upb_oneof_iter *iter);
-void upb_oneof_iter_setdone(upb_oneof_iter *iter);
+const char *upb_filedef_name(const upb_filedef *f);
+const char *upb_filedef_package(const upb_filedef *f);
+const char *upb_filedef_phpprefix(const upb_filedef *f);
+const char *upb_filedef_phpnamespace(const upb_filedef *f);
+upb_syntax_t upb_filedef_syntax(const upb_filedef *f);
+int upb_filedef_depcount(const upb_filedef *f);
+int upb_filedef_msgcount(const upb_filedef *f);
+int upb_filedef_enumcount(const upb_filedef *f);
+const upb_filedef *upb_filedef_dep(const upb_filedef *f, int i);
+const upb_msgdef *upb_filedef_msg(const upb_filedef *f, int i);
+const upb_enumdef *upb_filedef_enum(const upb_filedef *f, int i);
 
 UPB_END_EXTERN_C
 
-
-/* upb::FileDef ***************************************************************/
-
 #ifdef __cplusplus
 
 /* Class that represents a .proto file with some things defined in it.
  *
  * Many users won't care about FileDefs, but they are necessary if you want to
  * read the values of file-level options. */
-class upb::FileDef {
+class upb::FileDefPtr {
  public:
+  explicit FileDefPtr(const upb_filedef *ptr) : ptr_(ptr) {}
+
+  const upb_filedef* ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
+
   /* Get/set name of the file (eg. "foo/bar.proto"). */
-  const char* name() const;
+  const char* name() const { return upb_filedef_name(ptr_); }
 
   /* Package name for definitions inside the file (eg. "foo.bar"). */
-  const char* package() const;
+  const char* package() const { return upb_filedef_package(ptr_); }
 
   /* Sets the php class prefix which is prepended to all php generated classes
    * from this .proto. Default is empty. */
-  const char* phpprefix() const;
+  const char* phpprefix() const { return upb_filedef_phpprefix(ptr_); }
 
   /* Use this option to change the namespace of php generated classes. Default
    * is empty. When this option is empty, the package name will be used for
    * determining the namespace. */
-  const char* phpnamespace() const;
+  const char* phpnamespace() const { return upb_filedef_phpnamespace(ptr_); }
 
   /* Syntax for the file.  Defaults to proto2. */
-  upb_syntax_t syntax() const;
+  upb_syntax_t syntax() const { return upb_filedef_syntax(ptr_); }
 
   /* Get the list of dependencies from the file.  These are returned in the
-   * order that they were added to the FileDef. */
-  int dependency_count() const;
-  const FileDef* dependency(int index) const;
-
- private:
-  UPB_DISALLOW_POD_OPS(FileDef, upb::FileDef)
-};
-
-#endif
-
-UPB_BEGIN_EXTERN_C
-
-const char *upb_filedef_name(const upb_filedef *f);
-const char *upb_filedef_package(const upb_filedef *f);
-const char *upb_filedef_phpprefix(const upb_filedef *f);
-const char *upb_filedef_phpnamespace(const upb_filedef *f);
-upb_syntax_t upb_filedef_syntax(const upb_filedef *f);
-int upb_filedef_depcount(const upb_filedef *f);
-int upb_filedef_msgcount(const upb_filedef *f);
-int upb_filedef_enumcount(const upb_filedef *f);
-const upb_filedef *upb_filedef_dep(const upb_filedef *f, int i);
-const upb_msgdef *upb_filedef_msg(const upb_filedef *f, int i);
-const upb_enumdef *upb_filedef_enum(const upb_filedef *f, int i);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-/* Non-const methods in upb::SymbolTable are NOT thread-safe. */
-class upb::SymbolTable {
- public:
-  /* Returns a new symbol table with a single ref owned by "owner."
-   * Returns NULL if memory allocation failed. */
-  static SymbolTable* New();
-  static void Free(upb::SymbolTable* table);
-
-  /* Finds an entry in the symbol table with this exact name.  If not found,
-   * returns NULL. */
-  const MessageDef* LookupMessage(const char *sym) const;
-  const EnumDef* LookupEnum(const char *sym) const;
-
-  /* TODO: iteration? */
-
-  /* Adds the given serialized FileDescriptorProto to the pool. */
-  bool AddFile(const google_protobuf_FileDescriptorProto *file_proto,
-               Status *status);
-
-  /* Adds the given serialized FileDescriptorSet to the pool. */
-  bool AddSet(const char *set, size_t len, Status *status);
+   * order that they were added to the FileDefPtr. */
+  int dependency_count() const { return upb_filedef_depcount(ptr_); }
+  const FileDefPtr dependency(int index) const {
+    return FileDefPtr(upb_filedef_dep(ptr_, index));
+  }
 
  private:
-  UPB_DISALLOW_POD_OPS(SymbolTable, upb::SymbolTable)
+  const upb_filedef* ptr_;
 };
 
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
+/* upb_symtab *****************************************************************/
 
-/* Native C API. */
+UPB_BEGIN_EXTERN_C
 
 upb_symtab *upb_symtab_new();
 void upb_symtab_free(upb_symtab* s);
@@ -725,299 +798,43 @@ bool _upb_symtab_loaddefinit(upb_symtab *s, const upb_def_init *init);
 UPB_END_EXTERN_C
 
 #ifdef __cplusplus
-/* C++ inline wrappers. */
-namespace upb {
-inline SymbolTable* SymbolTable::New() {
-  return upb_symtab_new();
-}
-inline void SymbolTable::Free(SymbolTable* s) {
-  upb_symtab_free(s);
-}
-inline const MessageDef *SymbolTable::LookupMessage(const char *sym) const {
-  return upb_symtab_lookupmsg(this, sym);
-}
-inline bool SymbolTable::AddFile(
-    const google_protobuf_FileDescriptorProto *file_proto, Status *status) {
-  return upb_symtab_addfile(this, file_proto, status);
-}
-}  /* namespace upb */
-#endif
-
-#ifdef __cplusplus
-
-UPB_INLINE const char* upb_safecstr(const std::string& str) {
-  UPB_ASSERT(str.size() == std::strlen(str.c_str()));
-  return str.c_str();
-}
-
-/* Inline C++ wrappers. */
-namespace upb {
-
-inline const char* FieldDef::full_name() const {
-  return upb_fielddef_fullname(this);
-}
-inline FieldDef::Type FieldDef::type() const { return upb_fielddef_type(this); }
-inline FieldDef::DescriptorType FieldDef::descriptor_type() const {
-  return upb_fielddef_descriptortype(this);
-}
-inline FieldDef::Label FieldDef::label() const {
-  return upb_fielddef_label(this);
-}
-inline uint32_t FieldDef::number() const { return upb_fielddef_number(this); }
-inline const char* FieldDef::name() const { return upb_fielddef_name(this); }
-inline bool FieldDef::is_extension() const {
-  return upb_fielddef_isextension(this);
-}
-inline size_t FieldDef::GetJsonName(char* buf, size_t len) const {
-  return upb_fielddef_getjsonname(this, buf, len);
-}
-inline bool FieldDef::lazy() const {
-  return upb_fielddef_lazy(this);
-}
-inline bool FieldDef::packed() const {
-  return upb_fielddef_packed(this);
-}
-inline uint32_t FieldDef::index() const {
-  return upb_fielddef_index(this);
-}
-inline const MessageDef* FieldDef::containing_type() const {
-  return upb_fielddef_containingtype(this);
-}
-inline const OneofDef* FieldDef::containing_oneof() const {
-  return upb_fielddef_containingoneof(this);
-}
-inline bool FieldDef::IsSubMessage() const {
-  return upb_fielddef_issubmsg(this);
-}
-inline bool FieldDef::IsString() const { return upb_fielddef_isstring(this); }
-inline bool FieldDef::IsSequence() const { return upb_fielddef_isseq(this); }
-inline bool FieldDef::IsMap() const { return upb_fielddef_ismap(this); }
-inline int64_t FieldDef::default_int64() const {
-  return upb_fielddef_defaultint64(this);
-}
-inline int32_t FieldDef::default_int32() const {
-  return upb_fielddef_defaultint32(this);
-}
-inline uint64_t FieldDef::default_uint64() const {
-  return upb_fielddef_defaultuint64(this);
-}
-inline uint32_t FieldDef::default_uint32() const {
-  return upb_fielddef_defaultuint32(this);
-}
-inline bool FieldDef::default_bool() const {
-  return upb_fielddef_defaultbool(this);
-}
-inline float FieldDef::default_float() const {
-  return upb_fielddef_defaultfloat(this);
-}
-inline double FieldDef::default_double() const {
-  return upb_fielddef_defaultdouble(this);
-}
-inline const char* FieldDef::default_string(size_t* len) const {
-  return upb_fielddef_defaultstr(this, len);
-}
-inline const MessageDef *FieldDef::message_subdef() const {
-  return upb_fielddef_msgsubdef(this);
-}
-inline const EnumDef *FieldDef::enum_subdef() const {
-  return upb_fielddef_enumsubdef(this);
-}
-
-inline const char *MessageDef::full_name() const {
-  return upb_msgdef_fullname(this);
-}
-inline const char *MessageDef::name() const {
-  return upb_msgdef_name(this);
-}
-inline upb_syntax_t MessageDef::syntax() const {
-  return upb_msgdef_syntax(this);
-}
-inline int MessageDef::field_count() const {
-  return upb_msgdef_numfields(this);
-}
-inline int MessageDef::oneof_count() const {
-  return upb_msgdef_numoneofs(this);
-}
-inline const FieldDef* MessageDef::FindFieldByNumber(uint32_t number) const {
-  return upb_msgdef_itof(this, number);
-}
-inline const FieldDef *MessageDef::FindFieldByName(const char *name,
-                                                   size_t len) const {
-  return upb_msgdef_ntof(this, name, len);
-}
-inline const OneofDef* MessageDef::FindOneofByName(const char* name,
-                                                   size_t len) const {
-  return upb_msgdef_ntoo(this, name, len);
-}
-inline bool MessageDef::mapentry() const {
-  return upb_msgdef_mapentry(this);
-}
-inline upb_wellknowntype_t MessageDef::wellknowntype() const {
-  return upb_msgdef_wellknowntype(this);
-}
-inline bool MessageDef::isnumberwrapper() const {
-  return upb_msgdef_isnumberwrapper(this);
-}
-inline MessageDef::const_field_iterator MessageDef::field_begin() const {
-  return const_field_iterator(this);
-}
-inline MessageDef::const_field_iterator MessageDef::field_end() const {
-  return const_field_iterator::end(this);
-}
 
-inline MessageDef::const_oneof_iterator MessageDef::oneof_begin() const {
-  return const_oneof_iterator(this);
-}
-inline MessageDef::const_oneof_iterator MessageDef::oneof_end() const {
-  return const_oneof_iterator::end(this);
-}
+/* Non-const methods in upb::SymbolTable are NOT thread-safe. */
+class upb::SymbolTable {
+ public:
+  SymbolTable() : ptr_(upb_symtab_new(), upb_symtab_free) {}
+  explicit SymbolTable(upb_symtab* s) : ptr_(s, upb_symtab_free) {}
 
-inline MessageDef::const_field_iterator::const_field_iterator(
-    const MessageDef* md) {
-  upb_msg_field_begin(&iter_, md);
-}
-inline MessageDef::const_field_iterator MessageDef::const_field_iterator::end(
-    const MessageDef *md) {
-  MessageDef::const_field_iterator iter(md);
-  upb_msg_field_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline const FieldDef* MessageDef::const_field_iterator::operator*() const {
-  return upb_msg_iter_field(&iter_);
-}
-inline void MessageDef::const_field_iterator::operator++() {
-  return upb_msg_field_next(&iter_);
-}
-inline bool MessageDef::const_field_iterator::operator==(
-    const const_field_iterator &other) const {
-  return upb_inttable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool MessageDef::const_field_iterator::operator!=(
-    const const_field_iterator &other) const {
-  return !(*this == other);
-}
+  const upb_symtab* ptr() const { return ptr_.get(); }
+  upb_symtab* ptr() { return ptr_.get(); }
 
-inline MessageDef::const_oneof_iterator::const_oneof_iterator(
-    const MessageDef* md) {
-  upb_msg_oneof_begin(&iter_, md);
-}
-inline MessageDef::const_oneof_iterator MessageDef::const_oneof_iterator::end(
-    const MessageDef *md) {
-  MessageDef::const_oneof_iterator iter(md);
-  upb_msg_oneof_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline const OneofDef* MessageDef::const_oneof_iterator::operator*() const {
-  return upb_msg_iter_oneof(&iter_);
-}
-inline void MessageDef::const_oneof_iterator::operator++() {
-  return upb_msg_oneof_next(&iter_);
-}
-inline bool MessageDef::const_oneof_iterator::operator==(
-    const const_oneof_iterator &other) const {
-  return upb_strtable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool MessageDef::const_oneof_iterator::operator!=(
-    const const_oneof_iterator &other) const {
-  return !(*this == other);
-}
+  /* Finds an entry in the symbol table with this exact name.  If not found,
+   * returns NULL. */
+  MessageDefPtr LookupMessage(const char *sym) const {
+    return MessageDefPtr(upb_symtab_lookupmsg(ptr_.get(), sym));
+  }
 
-inline const char* EnumDef::full_name() const {
-  return upb_enumdef_fullname(this);
-}
-inline const char* EnumDef::name() const {
-  return upb_enumdef_name(this);
-}
-inline int32_t EnumDef::default_value() const {
-  return upb_enumdef_default(this);
-}
-inline int EnumDef::value_count() const { return upb_enumdef_numvals(this); }
-inline bool EnumDef::FindValueByName(const char* name, int32_t *num) const {
-  return upb_enumdef_ntoiz(this, name, num);
-}
-inline const char* EnumDef::FindValueByNumber(int32_t num) const {
-  return upb_enumdef_iton(this, num);
-}
+  const EnumDefPtr LookupEnum(const char *sym) const {
+    return EnumDefPtr(upb_symtab_lookupenum(ptr_.get(), sym));
+  }
 
-inline EnumDef::Iterator::Iterator(const EnumDef* e) {
-  upb_enum_begin(&iter_, e);
-}
-inline int32_t EnumDef::Iterator::number() {
-  return upb_enum_iter_number(&iter_);
-}
-inline const char* EnumDef::Iterator::name() {
-  return upb_enum_iter_name(&iter_);
-}
-inline bool EnumDef::Iterator::Done() { return upb_enum_done(&iter_); }
-inline void EnumDef::Iterator::Next() { return upb_enum_next(&iter_); }
+  /* TODO: iteration? */
 
-inline const MessageDef* OneofDef::containing_type() const {
-  return upb_oneofdef_containingtype(this);
-}
-inline const char* OneofDef::name() const {
-  return upb_oneofdef_name(this);
-}
-inline int OneofDef::field_count() const {
-  return upb_oneofdef_numfields(this);
-}
-inline const FieldDef* OneofDef::FindFieldByName(const char* name,
-                                                 size_t len) const {
-  return upb_oneofdef_ntof(this, name, len);
-}
-inline const FieldDef* OneofDef::FindFieldByNumber(uint32_t num) const {
-  return upb_oneofdef_itof(this, num);
-}
-inline OneofDef::const_iterator OneofDef::begin() const {
-  return const_iterator(this);
-}
-inline OneofDef::const_iterator OneofDef::end() const {
-  return const_iterator::end(this);
-}
+  /* Adds the given serialized FileDescriptorProto to the pool. */
+  bool AddFile(const google_protobuf_FileDescriptorProto *file_proto,
+               Status *status) {
+    return upb_symtab_addfile(ptr_.get(), file_proto, status);
+  }
 
-inline OneofDef::const_iterator::const_iterator(const OneofDef* md) {
-  upb_oneof_begin(&iter_, md);
-}
-inline OneofDef::const_iterator OneofDef::const_iterator::end(
-    const OneofDef *md) {
-  OneofDef::const_iterator iter(md);
-  upb_oneof_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline const FieldDef* OneofDef::const_iterator::operator*() const {
-  return upb_msg_iter_field(&iter_);
-}
-inline void OneofDef::const_iterator::operator++() {
-  return upb_oneof_next(&iter_);
-}
-inline bool OneofDef::const_iterator::operator==(
-    const const_iterator &other) const {
-  return upb_inttable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool OneofDef::const_iterator::operator!=(
-    const const_iterator &other) const {
-  return !(*this == other);
-}
+ private:
+  std::unique_ptr<upb_symtab, decltype(&upb_symtab_free)> ptr_;
+};
 
-inline const char* FileDef::name() const {
-  return upb_filedef_name(this);
-}
-inline const char* FileDef::package() const {
-  return upb_filedef_package(this);
-}
-inline const char* FileDef::phpprefix() const {
-  return upb_filedef_phpprefix(this);
-}
-inline const char* FileDef::phpnamespace() const {
-  return upb_filedef_phpnamespace(this);
-}
-inline int FileDef::dependency_count() const {
-  return upb_filedef_depcount(this);
-}
-inline const FileDef* FileDef::dependency(int index) const {
-  return upb_filedef_dep(this, index);
+UPB_INLINE const char* upb_safecstr(const std::string& str) {
+  UPB_ASSERT(str.size() == std::strlen(str.c_str()));
+  return str.c_str();
 }
 
-}  /* namespace upb */
-#endif
+#endif  /* __cplusplus */
 
 #endif /* UPB_DEF_H_ */