Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/ruby/ext/google/protobuf_c/defs.c

Index: third_party/protobuf/ruby/ext/google/protobuf_c/defs.c
diff --git a/third_party/protobuf/ruby/ext/google/protobuf_c/defs.c b/third_party/protobuf/ruby/ext/google/protobuf_c/defs.c
deleted file mode 100644
index 0b2f977f54b0a8dbc99d89b7005bd978b3238233..0000000000000000000000000000000000000000
--- a/third_party/protobuf/ruby/ext/google/protobuf_c/defs.c
+++ /dev/null
@@ -1,1733 +0,0 @@
-// Protocol Buffers - Google's data interchange format
-// Copyright 2014 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#include "protobuf.h"
-
-// -----------------------------------------------------------------------------
-// Common utilities.
-// -----------------------------------------------------------------------------
-
-static const char* get_str(VALUE str) {
-  Check_Type(str, T_STRING);
-  return RSTRING_PTR(str);
-}
-
-static VALUE rb_str_maybe_null(const char* s) {
-  if (s == NULL) {
-    s = "";
-  }
-  return rb_str_new2(s);
-}
-
-static upb_def* check_notfrozen(const upb_def* def) {
-  if (upb_def_isfrozen(def)) {
-    rb_raise(rb_eRuntimeError,
-             "Attempt to modify a frozen descriptor. Once descriptors are "
-             "added to the descriptor pool, they may not be modified.");
-  }
-  return (upb_def*)def;
-}
-
-static upb_msgdef* check_msg_notfrozen(const upb_msgdef* def) {
-  return upb_downcast_msgdef_mutable(check_notfrozen((const upb_def*)def));
-}
-
-static upb_fielddef* check_field_notfrozen(const upb_fielddef* def) {
-  return upb_downcast_fielddef_mutable(check_notfrozen((const upb_def*)def));
-}
-
-static upb_oneofdef* check_oneof_notfrozen(const upb_oneofdef* def) {
-  return (upb_oneofdef*)check_notfrozen((const upb_def*)def);
-}
-
-static upb_enumdef* check_enum_notfrozen(const upb_enumdef* def) {
-  return (upb_enumdef*)check_notfrozen((const upb_def*)def);
-}
-
-// -----------------------------------------------------------------------------
-// DescriptorPool.
-// -----------------------------------------------------------------------------
-
-#define DEFINE_CLASS(name, string_name)                             \
-    VALUE c ## name;                                                \
-    const rb_data_type_t _ ## name ## _type = {                     \
-      string_name,                                                  \
-      { name ## _mark, name ## _free, NULL },                       \
-    };                                                              \
-    name* ruby_to_ ## name(VALUE val) {                             \
-      name* ret;                                                    \
-      TypedData_Get_Struct(val, name, &_ ## name ## _type, ret);    \
-      return ret;                                                   \
-    }                                                               \
-
-#define DEFINE_SELF(type, var, rb_var)                              \
-    type* var = ruby_to_ ## type(rb_var);
-
-// Global singleton DescriptorPool. The user is free to create others, but this
-// is used by generated code.
-VALUE generated_pool;
-
-DEFINE_CLASS(DescriptorPool, "Google::Protobuf::DescriptorPool");
-
-void DescriptorPool_mark(void* _self) {
-}
-
-void DescriptorPool_free(void* _self) {
-  DescriptorPool* self = _self;
-  upb_symtab_unref(self->symtab, &self->symtab);
-  xfree(self);
-}
-
-/*
- * call-seq:
- *     DescriptorPool.new => pool
- *
- * Creates a new, empty, descriptor pool.
- */
-VALUE DescriptorPool_alloc(VALUE klass) {
-  DescriptorPool* self = ALLOC(DescriptorPool);
-  self->symtab = upb_symtab_new(&self->symtab);
-  return TypedData_Wrap_Struct(klass, &_DescriptorPool_type, self);
-}
-
-void DescriptorPool_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "DescriptorPool", rb_cObject);
-  rb_define_alloc_func(klass, DescriptorPool_alloc);
-  rb_define_method(klass, "add", DescriptorPool_add, 1);
-  rb_define_method(klass, "build", DescriptorPool_build, 0);
-  rb_define_method(klass, "lookup", DescriptorPool_lookup, 1);
-  rb_define_singleton_method(klass, "generated_pool",
-                             DescriptorPool_generated_pool, 0);
-  cDescriptorPool = klass;
-  rb_gc_register_address(&cDescriptorPool);
-
-  generated_pool = rb_class_new_instance(0, NULL, klass);
-  rb_gc_register_address(&generated_pool);
-}
-
-static void add_descriptor_to_pool(DescriptorPool* self,
-                                   Descriptor* descriptor) {
-  CHECK_UPB(
-      upb_symtab_add(self->symtab, (upb_def**)&descriptor->msgdef, 1,
-                     NULL, &status),
-      "Adding Descriptor to DescriptorPool failed");
-}
-
-static void add_enumdesc_to_pool(DescriptorPool* self,
-                                 EnumDescriptor* enumdesc) {
-  CHECK_UPB(
-      upb_symtab_add(self->symtab, (upb_def**)&enumdesc->enumdef, 1,
-                     NULL, &status),
-      "Adding EnumDescriptor to DescriptorPool failed");
-}
-
-/*
- * call-seq:
- *     DescriptorPool.add(descriptor)
- *
- * Adds the given Descriptor or EnumDescriptor to this pool. All references to
- * other types in a Descriptor's fields must be resolvable within this pool or
- * an exception will be raised.
- */
-VALUE DescriptorPool_add(VALUE _self, VALUE def) {
-  DEFINE_SELF(DescriptorPool, self, _self);
-  VALUE def_klass = rb_obj_class(def);
-  if (def_klass == cDescriptor) {
-    add_descriptor_to_pool(self, ruby_to_Descriptor(def));
-  } else if (def_klass == cEnumDescriptor) {
-    add_enumdesc_to_pool(self, ruby_to_EnumDescriptor(def));
-  } else {
-    rb_raise(rb_eArgError,
-             "Second argument must be a Descriptor or EnumDescriptor.");
-  }
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     DescriptorPool.build(&block)
- *
- * Invokes the block with a Builder instance as self. All message and enum types
- * added within the block are committed to the pool atomically, and may refer
- * (co)recursively to each other. The user should call Builder#add_message and
- * Builder#add_enum within the block as appropriate.  This is the recommended,
- * idiomatic way to define new message and enum types.
- */
-VALUE DescriptorPool_build(VALUE _self) {
-  VALUE ctx = rb_class_new_instance(0, NULL, cBuilder);
-  VALUE block = rb_block_proc();
-  rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_funcall(ctx, rb_intern("finalize_to_pool"), 1, _self);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     DescriptorPool.lookup(name) => descriptor
- *
- * Finds a Descriptor or EnumDescriptor by name and returns it, or nil if none
- * exists with the given name.
- */
-VALUE DescriptorPool_lookup(VALUE _self, VALUE name) {
-  DEFINE_SELF(DescriptorPool, self, _self);
-  const char* name_str = get_str(name);
-  const upb_def* def = upb_symtab_lookup(self->symtab, name_str);
-  if (!def) {
-    return Qnil;
-  }
-  return get_def_obj(def);
-}
-
-/*
- * call-seq:
- *     DescriptorPool.generated_pool => descriptor_pool
- *
- * Class method that returns the global DescriptorPool. This is a singleton into
- * which generated-code message and enum types are registered. The user may also
- * register types in this pool for convenience so that they do not have to hold
- * a reference to a private pool instance.
- */
-VALUE DescriptorPool_generated_pool(VALUE _self) {
-  return generated_pool;
-}
-
-// -----------------------------------------------------------------------------
-// Descriptor.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(Descriptor, "Google::Protobuf::Descriptor");
-
-void Descriptor_mark(void* _self) {
-  Descriptor* self = _self;
-  rb_gc_mark(self->klass);
-  rb_gc_mark(self->typeclass_references);
-}
-
-void Descriptor_free(void* _self) {
-  Descriptor* self = _self;
-  upb_msgdef_unref(self->msgdef, &self->msgdef);
-  if (self->layout) {
-    free_layout(self->layout);
-  }
-  if (self->fill_handlers) {
-    upb_handlers_unref(self->fill_handlers, &self->fill_handlers);
-  }
-  if (self->fill_method) {
-    upb_pbdecodermethod_unref(self->fill_method, &self->fill_method);
-  }
-  if (self->pb_serialize_handlers) {
-    upb_handlers_unref(self->pb_serialize_handlers,
-                       &self->pb_serialize_handlers);
-  }
-  if (self->json_serialize_handlers) {
-    upb_handlers_unref(self->json_serialize_handlers,
-                       &self->json_serialize_handlers);
-  }
-  xfree(self);
-}
-
-/*
- * call-seq:
- *     Descriptor.new => descriptor
- *
- * Creates a new, empty, message type descriptor. At a minimum, its name must be
- * set before it is added to a pool. It cannot be used to create messages until
- * it is added to a pool, after which it becomes immutable (as part of a
- * finalization process).
- */
-VALUE Descriptor_alloc(VALUE klass) {
-  Descriptor* self = ALLOC(Descriptor);
-  VALUE ret = TypedData_Wrap_Struct(klass, &_Descriptor_type, self);
-  self->msgdef = upb_msgdef_new(&self->msgdef);
-  self->klass = Qnil;
-  self->layout = NULL;
-  self->fill_handlers = NULL;
-  self->fill_method = NULL;
-  self->pb_serialize_handlers = NULL;
-  self->json_serialize_handlers = NULL;
-  self->typeclass_references = rb_ary_new();
-  return ret;
-}
-
-void Descriptor_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "Descriptor", rb_cObject);
-  rb_define_alloc_func(klass, Descriptor_alloc);
-  rb_define_method(klass, "each", Descriptor_each, 0);
-  rb_define_method(klass, "lookup", Descriptor_lookup, 1);
-  rb_define_method(klass, "add_field", Descriptor_add_field, 1);
-  rb_define_method(klass, "add_oneof", Descriptor_add_oneof, 1);
-  rb_define_method(klass, "each_oneof", Descriptor_each_oneof, 0);
-  rb_define_method(klass, "lookup_oneof", Descriptor_lookup_oneof, 1);
-  rb_define_method(klass, "msgclass", Descriptor_msgclass, 0);
-  rb_define_method(klass, "name", Descriptor_name, 0);
-  rb_define_method(klass, "name=", Descriptor_name_set, 1);
-  rb_include_module(klass, rb_mEnumerable);
-  cDescriptor = klass;
-  rb_gc_register_address(&cDescriptor);
-}
-
-/*
- * call-seq:
- *     Descriptor.name => name
- *
- * Returns the name of this message type as a fully-qualfied string (e.g.,
- * My.Package.MessageType).
- */
-VALUE Descriptor_name(VALUE _self) {
-  DEFINE_SELF(Descriptor, self, _self);
-  return rb_str_maybe_null(upb_msgdef_fullname(self->msgdef));
-}
-
-/*
- * call-seq:
- *    Descriptor.name = name
- *
- * Assigns a name to this message type. The descriptor must not have been added
- * to a pool yet.
- */
-VALUE Descriptor_name_set(VALUE _self, VALUE str) {
-  DEFINE_SELF(Descriptor, self, _self);
-  upb_msgdef* mut_def = check_msg_notfrozen(self->msgdef);
-  const char* name = get_str(str);
-  CHECK_UPB(
-      upb_msgdef_setfullname(mut_def, name, &status),
-      "Error setting Descriptor name");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Descriptor.each(&block)
- *
- * Iterates over fields in this message type, yielding to the block on each one.
- */
-VALUE Descriptor_each(VALUE _self) {
-  DEFINE_SELF(Descriptor, self, _self);
-
-  upb_msg_field_iter it;
-  for (upb_msg_field_begin(&it, self->msgdef);
-       !upb_msg_field_done(&it);
-       upb_msg_field_next(&it)) {
-    const upb_fielddef* field = upb_msg_iter_field(&it);
-    VALUE obj = get_def_obj(field);
-    rb_yield(obj);
-  }
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Descriptor.lookup(name) => FieldDescriptor
- *
- * Returns the field descriptor for the field with the given name, if present,
- * or nil if none.
- */
-VALUE Descriptor_lookup(VALUE _self, VALUE name) {
-  DEFINE_SELF(Descriptor, self, _self);
-  const char* s = get_str(name);
-  const upb_fielddef* field = upb_msgdef_ntofz(self->msgdef, s);
-  if (field == NULL) {
-    return Qnil;
-  }
-  return get_def_obj(field);
-}
-
-/*
- * call-seq:
- *     Descriptor.add_field(field) => nil
- *
- * Adds the given FieldDescriptor to this message type. This descriptor must not
- * have been added to a pool yet. Raises an exception if a field with the same
- * name or number already exists. Sub-type references (e.g. for fields of type
- * message) are not resolved at this point.
- */
-VALUE Descriptor_add_field(VALUE _self, VALUE obj) {
-  DEFINE_SELF(Descriptor, self, _self);
-  upb_msgdef* mut_def = check_msg_notfrozen(self->msgdef);
-  FieldDescriptor* def = ruby_to_FieldDescriptor(obj);
-  upb_fielddef* mut_field_def = check_field_notfrozen(def->fielddef);
-  CHECK_UPB(
-      upb_msgdef_addfield(mut_def, mut_field_def, NULL, &status),
-      "Adding field to Descriptor failed");
-  add_def_obj(def->fielddef, obj);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Descriptor.add_oneof(oneof) => nil
- *
- * Adds the given OneofDescriptor to this message type. This descriptor must not
- * have been added to a pool yet. Raises an exception if a oneof with the same
- * name already exists, or if any of the oneof's fields' names or numbers
- * conflict with an existing field in this message type. All fields in the oneof
- * are added to the message descriptor. Sub-type references (e.g. for fields of
- * type message) are not resolved at this point.
- */
-VALUE Descriptor_add_oneof(VALUE _self, VALUE obj) {
-  DEFINE_SELF(Descriptor, self, _self);
-  upb_msgdef* mut_def = check_msg_notfrozen(self->msgdef);
-  OneofDescriptor* def = ruby_to_OneofDescriptor(obj);
-  upb_oneofdef* mut_oneof_def = check_oneof_notfrozen(def->oneofdef);
-  CHECK_UPB(
-      upb_msgdef_addoneof(mut_def, mut_oneof_def, NULL, &status),
-      "Adding oneof to Descriptor failed");
-  add_def_obj(def->oneofdef, obj);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Descriptor.each_oneof(&block) => nil
- *
- * Invokes the given block for each oneof in this message type, passing the
- * corresponding OneofDescriptor.
- */
-VALUE Descriptor_each_oneof(VALUE _self) {
-  DEFINE_SELF(Descriptor, self, _self);
-
-  upb_msg_oneof_iter it;
-  for (upb_msg_oneof_begin(&it, self->msgdef);
-       !upb_msg_oneof_done(&it);
-       upb_msg_oneof_next(&it)) {
-    const upb_oneofdef* oneof = upb_msg_iter_oneof(&it);
-    VALUE obj = get_def_obj(oneof);
-    rb_yield(obj);
-  }
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Descriptor.lookup_oneof(name) => OneofDescriptor
- *
- * Returns the oneof descriptor for the oneof with the given name, if present,
- * or nil if none.
- */
-VALUE Descriptor_lookup_oneof(VALUE _self, VALUE name) {
-  DEFINE_SELF(Descriptor, self, _self);
-  const char* s = get_str(name);
-  const upb_oneofdef* oneof = upb_msgdef_ntooz(self->msgdef, s);
-  if (oneof == NULL) {
-    return Qnil;
-  }
-  return get_def_obj(oneof);
-}
-
-/*
- * call-seq:
- *     Descriptor.msgclass => message_klass
- *
- * Returns the Ruby class created for this message type. Valid only once the
- * message type has been added to a pool.
- */
-VALUE Descriptor_msgclass(VALUE _self) {
-  DEFINE_SELF(Descriptor, self, _self);
-  if (!upb_def_isfrozen((const upb_def*)self->msgdef)) {
-    rb_raise(rb_eRuntimeError,
-             "Cannot fetch message class from a Descriptor not yet in a pool.");
-  }
-  if (self->klass == Qnil) {
-    self->klass = build_class_from_descriptor(self);
-  }
-  return self->klass;
-}
-
-// -----------------------------------------------------------------------------
-// FieldDescriptor.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(FieldDescriptor, "Google::Protobuf::FieldDescriptor");
-
-void FieldDescriptor_mark(void* _self) {
-}
-
-void FieldDescriptor_free(void* _self) {
-  FieldDescriptor* self = _self;
-  upb_fielddef_unref(self->fielddef, &self->fielddef);
-  xfree(self);
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.new => field
- *
- * Returns a new field descriptor. Its name, type, etc. must be set before it is
- * added to a message type.
- */
-VALUE FieldDescriptor_alloc(VALUE klass) {
-  FieldDescriptor* self = ALLOC(FieldDescriptor);
-  VALUE ret = TypedData_Wrap_Struct(klass, &_FieldDescriptor_type, self);
-  upb_fielddef* fielddef = upb_fielddef_new(&self->fielddef);
-  upb_fielddef_setpacked(fielddef, false);
-  self->fielddef = fielddef;
-  return ret;
-}
-
-void FieldDescriptor_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "FieldDescriptor", rb_cObject);
-  rb_define_alloc_func(klass, FieldDescriptor_alloc);
-  rb_define_method(klass, "name", FieldDescriptor_name, 0);
-  rb_define_method(klass, "name=", FieldDescriptor_name_set, 1);
-  rb_define_method(klass, "type", FieldDescriptor_type, 0);
-  rb_define_method(klass, "type=", FieldDescriptor_type_set, 1);
-  rb_define_method(klass, "label", FieldDescriptor_label, 0);
-  rb_define_method(klass, "label=", FieldDescriptor_label_set, 1);
-  rb_define_method(klass, "number", FieldDescriptor_number, 0);
-  rb_define_method(klass, "number=", FieldDescriptor_number_set, 1);
-  rb_define_method(klass, "submsg_name", FieldDescriptor_submsg_name, 0);
-  rb_define_method(klass, "submsg_name=", FieldDescriptor_submsg_name_set, 1);
-  rb_define_method(klass, "subtype", FieldDescriptor_subtype, 0);
-  rb_define_method(klass, "get", FieldDescriptor_get, 1);
-  rb_define_method(klass, "set", FieldDescriptor_set, 2);
-  cFieldDescriptor = klass;
-  rb_gc_register_address(&cFieldDescriptor);
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.name => name
- *
- * Returns the name of this field.
- */
-VALUE FieldDescriptor_name(VALUE _self) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  return rb_str_maybe_null(upb_fielddef_name(self->fielddef));
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.name = name
- *
- * Sets the name of this field. Cannot be called once the containing message
- * type, if any, is added to a pool.
- */
-VALUE FieldDescriptor_name_set(VALUE _self, VALUE str) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  const char* name = get_str(str);
-  CHECK_UPB(upb_fielddef_setname(mut_def, name, &status),
-            "Error setting FieldDescriptor name");
-  return Qnil;
-}
-
-upb_fieldtype_t ruby_to_fieldtype(VALUE type) {
-  if (TYPE(type) != T_SYMBOL) {
-    rb_raise(rb_eArgError, "Expected symbol for field type.");
-  }
-
-#define CONVERT(upb, ruby)                                           \
-  if (SYM2ID(type) == rb_intern( # ruby )) {                         \
-    return UPB_TYPE_ ## upb;                                         \
-  }
-
-  CONVERT(FLOAT, float);
-  CONVERT(DOUBLE, double);
-  CONVERT(BOOL, bool);
-  CONVERT(STRING, string);
-  CONVERT(BYTES, bytes);
-  CONVERT(MESSAGE, message);
-  CONVERT(ENUM, enum);
-  CONVERT(INT32, int32);
-  CONVERT(INT64, int64);
-  CONVERT(UINT32, uint32);
-  CONVERT(UINT64, uint64);
-
-#undef CONVERT
-
-  rb_raise(rb_eArgError, "Unknown field type.");
-  return 0;
-}
-
-VALUE fieldtype_to_ruby(upb_fieldtype_t type) {
-  switch (type) {
-#define CONVERT(upb, ruby)                                           \
-    case UPB_TYPE_ ## upb : return ID2SYM(rb_intern( # ruby ));
-    CONVERT(FLOAT, float);
-    CONVERT(DOUBLE, double);
-    CONVERT(BOOL, bool);
-    CONVERT(STRING, string);
-    CONVERT(BYTES, bytes);
-    CONVERT(MESSAGE, message);
-    CONVERT(ENUM, enum);
-    CONVERT(INT32, int32);
-    CONVERT(INT64, int64);
-    CONVERT(UINT32, uint32);
-    CONVERT(UINT64, uint64);
-#undef CONVERT
-  }
-  return Qnil;
-}
-
-upb_descriptortype_t ruby_to_descriptortype(VALUE type) {
-  if (TYPE(type) != T_SYMBOL) {
-    rb_raise(rb_eArgError, "Expected symbol for field type.");
-  }
-
-#define CONVERT(upb, ruby)                                           \
-  if (SYM2ID(type) == rb_intern( # ruby )) {                         \
-    return UPB_DESCRIPTOR_TYPE_ ## upb;                              \
-  }
-
-  CONVERT(FLOAT, float);
-  CONVERT(DOUBLE, double);
-  CONVERT(BOOL, bool);
-  CONVERT(STRING, string);
-  CONVERT(BYTES, bytes);
-  CONVERT(MESSAGE, message);
-  CONVERT(GROUP, group);
-  CONVERT(ENUM, enum);
-  CONVERT(INT32, int32);
-  CONVERT(INT64, int64);
-  CONVERT(UINT32, uint32);
-  CONVERT(UINT64, uint64);
-  CONVERT(SINT32, sint32);
-  CONVERT(SINT64, sint64);
-  CONVERT(FIXED32, fixed32);
-  CONVERT(FIXED64, fixed64);
-  CONVERT(SFIXED32, sfixed32);
-  CONVERT(SFIXED64, sfixed64);
-
-#undef CONVERT
-
-  rb_raise(rb_eArgError, "Unknown field type.");
-  return 0;
-}
-
-VALUE descriptortype_to_ruby(upb_descriptortype_t type) {
-  switch (type) {
-#define CONVERT(upb, ruby)                                           \
-    case UPB_DESCRIPTOR_TYPE_ ## upb : return ID2SYM(rb_intern( # ruby ));
-    CONVERT(FLOAT, float);
-    CONVERT(DOUBLE, double);
-    CONVERT(BOOL, bool);
-    CONVERT(STRING, string);
-    CONVERT(BYTES, bytes);
-    CONVERT(MESSAGE, message);
-    CONVERT(GROUP, group);
-    CONVERT(ENUM, enum);
-    CONVERT(INT32, int32);
-    CONVERT(INT64, int64);
-    CONVERT(UINT32, uint32);
-    CONVERT(UINT64, uint64);
-    CONVERT(SINT32, sint32);
-    CONVERT(SINT64, sint64);
-    CONVERT(FIXED32, fixed32);
-    CONVERT(FIXED64, fixed64);
-    CONVERT(SFIXED32, sfixed32);
-    CONVERT(SFIXED64, sfixed64);
-#undef CONVERT
-  }
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.type => type
- *
- * Returns this field's type, as a Ruby symbol, or nil if not yet set.
- *
- * Valid field types are:
- *     :int32, :int64, :uint32, :uint64, :float, :double, :bool, :string,
- *     :bytes, :message.
- */
-VALUE FieldDescriptor_type(VALUE _self) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  if (!upb_fielddef_typeisset(self->fielddef)) {
-    return Qnil;
-  }
-  return descriptortype_to_ruby(upb_fielddef_descriptortype(self->fielddef));
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.type = type
- *
- * Sets this field's type. Cannot be called if field is part of a message type
- * already in a pool.
- */
-VALUE FieldDescriptor_type_set(VALUE _self, VALUE type) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  upb_fielddef_setdescriptortype(mut_def, ruby_to_descriptortype(type));
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.label => label
- *
- * Returns this field's label (i.e., plurality), as a Ruby symbol.
- *
- * Valid field labels are:
- *     :optional, :repeated
- */
-VALUE FieldDescriptor_label(VALUE _self) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  switch (upb_fielddef_label(self->fielddef)) {
-#define CONVERT(upb, ruby)                                           \
-    case UPB_LABEL_ ## upb : return ID2SYM(rb_intern( # ruby ));
-
-    CONVERT(OPTIONAL, optional);
-    CONVERT(REQUIRED, required);
-    CONVERT(REPEATED, repeated);
-
-#undef CONVERT
-  }
-
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.label = label
- *
- * Sets the label on this field. Cannot be called if field is part of a message
- * type already in a pool.
- */
-VALUE FieldDescriptor_label_set(VALUE _self, VALUE label) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  if (TYPE(label) != T_SYMBOL) {
-    rb_raise(rb_eArgError, "Expected symbol for field label.");
-  }
-
-  upb_label_t upb_label = -1;
-  bool converted = false;
-
-#define CONVERT(upb, ruby)                                           \
-  if (SYM2ID(label) == rb_intern( # ruby )) {                        \
-    upb_label = UPB_LABEL_ ## upb;                                   \
-    converted = true;                                                \
-  }
-
-  CONVERT(OPTIONAL, optional);
-  CONVERT(REQUIRED, required);
-  CONVERT(REPEATED, repeated);
-
-#undef CONVERT
-
-  if (!converted) {
-    rb_raise(rb_eArgError, "Unknown field label.");
-  }
-
-  upb_fielddef_setlabel(mut_def, upb_label);
-
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.number => number
- *
- * Returns the tag number for this field.
- */
-VALUE FieldDescriptor_number(VALUE _self) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  return INT2NUM(upb_fielddef_number(self->fielddef));
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.number = number
- *
- * Sets the tag number for this field. Cannot be called if field is part of a
- * message type already in a pool.
- */
-VALUE FieldDescriptor_number_set(VALUE _self, VALUE number) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  CHECK_UPB(upb_fielddef_setnumber(mut_def, NUM2INT(number), &status),
-            "Error setting field number");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.submsg_name => submsg_name
- *
- * Returns the name of the message or enum type corresponding to this field, if
- * it is a message or enum field (respectively), or nil otherwise. This type
- * name will be resolved within the context of the pool to which the containing
- * message type is added.
- */
-VALUE FieldDescriptor_submsg_name(VALUE _self) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  if (!upb_fielddef_hassubdef(self->fielddef)) {
-    return Qnil;
-  }
-  return rb_str_maybe_null(upb_fielddef_subdefname(self->fielddef));
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.submsg_name = submsg_name
- *
- * Sets the name of the message or enum type corresponding to this field, if it
- * is a message or enum field (respectively). This type name will be resolved
- * within the context of the pool to which the containing message type is added.
- * Cannot be called on field that are not of message or enum type, or on fields
- * that are part of a message type already added to a pool.
- */
-VALUE FieldDescriptor_submsg_name_set(VALUE _self, VALUE value) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  if (!upb_fielddef_hassubdef(self->fielddef)) {
-    rb_raise(rb_eTypeError, "FieldDescriptor does not have subdef.");
-  }
-  const char* str = get_str(value);
-  CHECK_UPB(upb_fielddef_setsubdefname(mut_def, str, &status),
-            "Error setting submessage name");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.subtype => message_or_enum_descriptor
- *
- * Returns the message or enum descriptor corresponding to this field's type if
- * it is a message or enum field, respectively, or nil otherwise. Cannot be
- * called *until* the containing message type is added to a pool (and thus
- * resolved).
- */
-VALUE FieldDescriptor_subtype(VALUE _self) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  if (!upb_fielddef_hassubdef(self->fielddef)) {
-    return Qnil;
-  }
-  const upb_def* def = upb_fielddef_subdef(self->fielddef);
-  if (def == NULL) {
-    return Qnil;
-  }
-  return get_def_obj(def);
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.get(message) => value
- *
- * Returns the value set for this field on the given message. Raises an
- * exception if message is of the wrong type.
- */
-VALUE FieldDescriptor_get(VALUE _self, VALUE msg_rb) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  MessageHeader* msg;
-  TypedData_Get_Struct(msg_rb, MessageHeader, &Message_type, msg);
-  if (msg->descriptor->msgdef != upb_fielddef_containingtype(self->fielddef)) {
-    rb_raise(rb_eTypeError, "get method called on wrong message type");
-  }
-  return layout_get(msg->descriptor->layout, Message_data(msg), self->fielddef);
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.set(message, value)
- *
- * Sets the value corresponding to this field to the given value on the given
- * message. Raises an exception if message is of the wrong type. Performs the
- * ordinary type-checks for field setting.
- */
-VALUE FieldDescriptor_set(VALUE _self, VALUE msg_rb, VALUE value) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  MessageHeader* msg;
-  TypedData_Get_Struct(msg_rb, MessageHeader, &Message_type, msg);
-  if (msg->descriptor->msgdef != upb_fielddef_containingtype(self->fielddef)) {
-    rb_raise(rb_eTypeError, "set method called on wrong message type");
-  }
-  layout_set(msg->descriptor->layout, Message_data(msg), self->fielddef, value);
-  return Qnil;
-}
-
-// -----------------------------------------------------------------------------
-// OneofDescriptor.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(OneofDescriptor, "Google::Protobuf::OneofDescriptor");
-
-void OneofDescriptor_mark(void* _self) {
-}
-
-void OneofDescriptor_free(void* _self) {
-  OneofDescriptor* self = _self;
-  upb_oneofdef_unref(self->oneofdef, &self->oneofdef);
-  xfree(self);
-}
-
-/*
- * call-seq:
- *     OneofDescriptor.new => oneof_descriptor
- *
- * Creates a new, empty, oneof descriptor. The oneof may only be modified prior
- * to being added to a message descriptor which is subsequently added to a pool.
- */
-VALUE OneofDescriptor_alloc(VALUE klass) {
-  OneofDescriptor* self = ALLOC(OneofDescriptor);
-  VALUE ret = TypedData_Wrap_Struct(klass, &_OneofDescriptor_type, self);
-  self->oneofdef = upb_oneofdef_new(&self->oneofdef);
-  return ret;
-}
-
-void OneofDescriptor_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "OneofDescriptor", rb_cObject);
-  rb_define_alloc_func(klass, OneofDescriptor_alloc);
-  rb_define_method(klass, "name", OneofDescriptor_name, 0);
-  rb_define_method(klass, "name=", OneofDescriptor_name_set, 1);
-  rb_define_method(klass, "add_field", OneofDescriptor_add_field, 1);
-  rb_define_method(klass, "each", OneofDescriptor_each, 0);
-  rb_include_module(klass, rb_mEnumerable);
-  cOneofDescriptor = klass;
-  rb_gc_register_address(&cOneofDescriptor);
-}
-
-/*
- * call-seq:
- *     OneofDescriptor.name => name
- *
- * Returns the name of this oneof.
- */
-VALUE OneofDescriptor_name(VALUE _self) {
-  DEFINE_SELF(OneofDescriptor, self, _self);
-  return rb_str_maybe_null(upb_oneofdef_name(self->oneofdef));
-}
-
-/*
- * call-seq:
- *     OneofDescriptor.name = name
- *
- * Sets a new name for this oneof. The oneof must not have been added to a
- * message descriptor yet.
- */
-VALUE OneofDescriptor_name_set(VALUE _self, VALUE value) {
-  DEFINE_SELF(OneofDescriptor, self, _self);
-  upb_oneofdef* mut_def = check_oneof_notfrozen(self->oneofdef);
-  const char* str = get_str(value);
-  CHECK_UPB(upb_oneofdef_setname(mut_def, str, &status),
-            "Error setting oneof name");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     OneofDescriptor.add_field(field) => nil
- *
- * Adds a field to this oneof. The field may have been added to this oneof in
- * the past, or the message to which this oneof belongs (if any), but may not
- * have already been added to any other oneof or message. Otherwise, an
- * exception is raised.
- *
- * All fields added to the oneof via this method will be automatically added to
- * the message to which this oneof belongs, if it belongs to one currently, or
- * else will be added to any message to which the oneof is later added at the
- * time that it is added.
- */
-VALUE OneofDescriptor_add_field(VALUE _self, VALUE obj) {
-  DEFINE_SELF(OneofDescriptor, self, _self);
-  upb_oneofdef* mut_def = check_oneof_notfrozen(self->oneofdef);
-  FieldDescriptor* def = ruby_to_FieldDescriptor(obj);
-  upb_fielddef* mut_field_def = check_field_notfrozen(def->fielddef);
-  CHECK_UPB(
-      upb_oneofdef_addfield(mut_def, mut_field_def, NULL, &status),
-      "Adding field to OneofDescriptor failed");
-  add_def_obj(def->fielddef, obj);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     OneofDescriptor.each(&block) => nil
- *
- * Iterates through fields in this oneof, yielding to the block on each one.
- */
-VALUE OneofDescriptor_each(VALUE _self, VALUE field) {
-  DEFINE_SELF(OneofDescriptor, self, _self);
-  upb_oneof_iter it;
-  for (upb_oneof_begin(&it, self->oneofdef);
-       !upb_oneof_done(&it);
-       upb_oneof_next(&it)) {
-    const upb_fielddef* f = upb_oneof_iter_field(&it);
-    VALUE obj = get_def_obj(f);
-    rb_yield(obj);
-  }
-  return Qnil;
-}
-
-// -----------------------------------------------------------------------------
-// EnumDescriptor.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(EnumDescriptor, "Google::Protobuf::EnumDescriptor");
-
-void EnumDescriptor_mark(void* _self) {
-  EnumDescriptor* self = _self;
-  rb_gc_mark(self->module);
-}
-
-void EnumDescriptor_free(void* _self) {
-  EnumDescriptor* self = _self;
-  upb_enumdef_unref(self->enumdef, &self->enumdef);
-  xfree(self);
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.new => enum_descriptor
- *
- * Creates a new, empty, enum descriptor. Must be added to a pool before the
- * enum type can be used. The enum type may only be modified prior to adding to
- * a pool.
- */
-VALUE EnumDescriptor_alloc(VALUE klass) {
-  EnumDescriptor* self = ALLOC(EnumDescriptor);
-  VALUE ret = TypedData_Wrap_Struct(klass, &_EnumDescriptor_type, self);
-  self->enumdef = upb_enumdef_new(&self->enumdef);
-  self->module = Qnil;
-  return ret;
-}
-
-void EnumDescriptor_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "EnumDescriptor", rb_cObject);
-  rb_define_alloc_func(klass, EnumDescriptor_alloc);
-  rb_define_method(klass, "name", EnumDescriptor_name, 0);
-  rb_define_method(klass, "name=", EnumDescriptor_name_set, 1);
-  rb_define_method(klass, "add_value", EnumDescriptor_add_value, 2);
-  rb_define_method(klass, "lookup_name", EnumDescriptor_lookup_name, 1);
-  rb_define_method(klass, "lookup_value", EnumDescriptor_lookup_value, 1);
-  rb_define_method(klass, "each", EnumDescriptor_each, 0);
-  rb_define_method(klass, "enummodule", EnumDescriptor_enummodule, 0);
-  rb_include_module(klass, rb_mEnumerable);
-  cEnumDescriptor = klass;
-  rb_gc_register_address(&cEnumDescriptor);
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.name => name
- *
- * Returns the name of this enum type.
- */
-VALUE EnumDescriptor_name(VALUE _self) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  return rb_str_maybe_null(upb_enumdef_fullname(self->enumdef));
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.name = name
- *
- * Sets the name of this enum type. Cannot be called if the enum type has
- * already been added to a pool.
- */
-VALUE EnumDescriptor_name_set(VALUE _self, VALUE str) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  upb_enumdef* mut_def = check_enum_notfrozen(self->enumdef);
-  const char* name = get_str(str);
-  CHECK_UPB(upb_enumdef_setfullname(mut_def, name, &status),
-            "Error setting EnumDescriptor name");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.add_value(key, value)
- *
- * Adds a new key => value mapping to this enum type. Key must be given as a
- * Ruby symbol. Cannot be called if the enum type has already been added to a
- * pool. Will raise an exception if the key or value is already in use.
- */
-VALUE EnumDescriptor_add_value(VALUE _self, VALUE name, VALUE number) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  upb_enumdef* mut_def = check_enum_notfrozen(self->enumdef);
-  const char* name_str = rb_id2name(SYM2ID(name));
-  int32_t val = NUM2INT(number);
-  CHECK_UPB(upb_enumdef_addval(mut_def, name_str, val, &status),
-            "Error adding value to enum");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.lookup_name(name) => value
- *
- * Returns the numeric value corresponding to the given key name (as a Ruby
- * symbol), or nil if none.
- */
-VALUE EnumDescriptor_lookup_name(VALUE _self, VALUE name) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  const char* name_str= rb_id2name(SYM2ID(name));
-  int32_t val = 0;
-  if (upb_enumdef_ntoiz(self->enumdef, name_str, &val)) {
-    return INT2NUM(val);
-  } else {
-    return Qnil;
-  }
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.lookup_value(name) => value
- *
- * Returns the key name (as a Ruby symbol) corresponding to the integer value,
- * or nil if none.
- */
-VALUE EnumDescriptor_lookup_value(VALUE _self, VALUE number) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  int32_t val = NUM2INT(number);
-  const char* name = upb_enumdef_iton(self->enumdef, val);
-  if (name != NULL) {
-    return ID2SYM(rb_intern(name));
-  } else {
-    return Qnil;
-  }
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.each(&block)
- *
- * Iterates over key => value mappings in this enum's definition, yielding to
- * the block with (key, value) arguments for each one.
- */
-VALUE EnumDescriptor_each(VALUE _self) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-
-  upb_enum_iter it;
-  for (upb_enum_begin(&it, self->enumdef);
-       !upb_enum_done(&it);
-       upb_enum_next(&it)) {
-    VALUE key = ID2SYM(rb_intern(upb_enum_iter_name(&it)));
-    VALUE number = INT2NUM(upb_enum_iter_number(&it));
-    rb_yield_values(2, key, number);
-  }
-
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.enummodule => module
- *
- * Returns the Ruby module corresponding to this enum type. Cannot be called
- * until the enum descriptor has been added to a pool.
- */
-VALUE EnumDescriptor_enummodule(VALUE _self) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  if (!upb_def_isfrozen((const upb_def*)self->enumdef)) {
-    rb_raise(rb_eRuntimeError,
-             "Cannot fetch enum module from an EnumDescriptor not yet "
-             "in a pool.");
-  }
-  if (self->module == Qnil) {
-    self->module = build_module_from_enumdesc(self);
-  }
-  return self->module;
-}
-
-// -----------------------------------------------------------------------------
-// MessageBuilderContext.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(MessageBuilderContext,
-    "Google::Protobuf::Internal::MessageBuilderContext");
-
-void MessageBuilderContext_mark(void* _self) {
-  MessageBuilderContext* self = _self;
-  rb_gc_mark(self->descriptor);
-  rb_gc_mark(self->builder);
-}
-
-void MessageBuilderContext_free(void* _self) {
-  MessageBuilderContext* self = _self;
-  xfree(self);
-}
-
-VALUE MessageBuilderContext_alloc(VALUE klass) {
-  MessageBuilderContext* self = ALLOC(MessageBuilderContext);
-  VALUE ret = TypedData_Wrap_Struct(
-      klass, &_MessageBuilderContext_type, self);
-  self->descriptor = Qnil;
-  self->builder = Qnil;
-  return ret;
-}
-
-void MessageBuilderContext_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "MessageBuilderContext", rb_cObject);
-  rb_define_alloc_func(klass, MessageBuilderContext_alloc);
-  rb_define_method(klass, "initialize",
-                   MessageBuilderContext_initialize, 2);
-  rb_define_method(klass, "optional", MessageBuilderContext_optional, -1);
-  rb_define_method(klass, "required", MessageBuilderContext_required, -1);
-  rb_define_method(klass, "repeated", MessageBuilderContext_repeated, -1);
-  rb_define_method(klass, "map", MessageBuilderContext_map, -1);
-  rb_define_method(klass, "oneof", MessageBuilderContext_oneof, 1);
-  cMessageBuilderContext = klass;
-  rb_gc_register_address(&cMessageBuilderContext);
-}
-
-/*
- * call-seq:
- *     MessageBuilderContext.new(desc, builder) => context
- *
- * Create a new message builder context around the given message descriptor and
- * builder context. This class is intended to serve as a DSL context to be used
- * with #instance_eval.
- */
-VALUE MessageBuilderContext_initialize(VALUE _self,
-                                       VALUE msgdef,
-                                       VALUE builder) {
-  DEFINE_SELF(MessageBuilderContext, self, _self);
-  self->descriptor = msgdef;
-  self->builder = builder;
-  return Qnil;
-}
-
-static VALUE msgdef_add_field(VALUE msgdef,
-                              const char* label, VALUE name,
-                              VALUE type, VALUE number,
-                              VALUE type_class) {
-  VALUE fielddef = rb_class_new_instance(0, NULL, cFieldDescriptor);
-  VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
-
-  rb_funcall(fielddef, rb_intern("label="), 1, ID2SYM(rb_intern(label)));
-  rb_funcall(fielddef, rb_intern("name="), 1, name_str);
-  rb_funcall(fielddef, rb_intern("type="), 1, type);
-  rb_funcall(fielddef, rb_intern("number="), 1, number);
-
-  if (type_class != Qnil) {
-    if (TYPE(type_class) != T_STRING) {
-      rb_raise(rb_eArgError, "Expected string for type class");
-    }
-    // Make it an absolute type name by prepending a dot.
-    type_class = rb_str_append(rb_str_new2("."), type_class);
-    rb_funcall(fielddef, rb_intern("submsg_name="), 1, type_class);
-  }
-
-  rb_funcall(msgdef, rb_intern("add_field"), 1, fielddef);
-  return fielddef;
-}
-
-/*
- * call-seq:
- *     MessageBuilderContext.optional(name, type, number, type_class = nil)
- *
- * Defines a new optional field on this message type with the given type, tag
- * number, and type class (for message and enum fields). The type must be a Ruby
- * symbol (as accepted by FieldDescriptor#type=) and the type_class must be a
- * string, if present (as accepted by FieldDescriptor#submsg_name=).
- */
-VALUE MessageBuilderContext_optional(int argc, VALUE* argv, VALUE _self) {
-  DEFINE_SELF(MessageBuilderContext, self, _self);
-
-  if (argc < 3) {
-    rb_raise(rb_eArgError, "Expected at least 3 arguments.");
-  }
-  VALUE name = argv[0];
-  VALUE type = argv[1];
-  VALUE number = argv[2];
-  VALUE type_class = (argc > 3) ? argv[3] : Qnil;
-
-  return msgdef_add_field(self->descriptor, "optional",
-                          name, type, number, type_class);
-}
-
-/*
- * call-seq:
- *     MessageBuilderContext.required(name, type, number, type_class = nil)
- *
- * Defines a new required field on this message type with the given type, tag
- * number, and type class (for message and enum fields). The type must be a Ruby
- * symbol (as accepted by FieldDescriptor#type=) and the type_class must be a
- * string, if present (as accepted by FieldDescriptor#submsg_name=).
- *
- * Proto3 does not have required fields, but this method exists for
- * completeness. Any attempt to add a message type with required fields to a
- * pool will currently result in an error.
- */
-VALUE MessageBuilderContext_required(int argc, VALUE* argv, VALUE _self) {
-  DEFINE_SELF(MessageBuilderContext, self, _self);
-
-  if (argc < 3) {
-    rb_raise(rb_eArgError, "Expected at least 3 arguments.");
-  }
-  VALUE name = argv[0];
-  VALUE type = argv[1];
-  VALUE number = argv[2];
-  VALUE type_class = (argc > 3) ? argv[3] : Qnil;
-
-  return msgdef_add_field(self->descriptor, "required",
-                          name, type, number, type_class);
-}
-
-/*
- * call-seq:
- *     MessageBuilderContext.repeated(name, type, number, type_class = nil)
- *
- * Defines a new repeated field on this message type with the given type, tag
- * number, and type class (for message and enum fields). The type must be a Ruby
- * symbol (as accepted by FieldDescriptor#type=) and the type_class must be a
- * string, if present (as accepted by FieldDescriptor#submsg_name=).
- */
-VALUE MessageBuilderContext_repeated(int argc, VALUE* argv, VALUE _self) {
-  DEFINE_SELF(MessageBuilderContext, self, _self);
-
-  if (argc < 3) {
-    rb_raise(rb_eArgError, "Expected at least 3 arguments.");
-  }
-  VALUE name = argv[0];
-  VALUE type = argv[1];
-  VALUE number = argv[2];
-  VALUE type_class = (argc > 3) ? argv[3] : Qnil;
-
-  return msgdef_add_field(self->descriptor, "repeated",
-                          name, type, number, type_class);
-}
-
-/*
- * call-seq:
- *     MessageBuilderContext.map(name, key_type, value_type, number,
- *                               value_type_class = nil)
- *
- * Defines a new map field on this message type with the given key and value
- * types, tag number, and type class (for message and enum value types). The key
- * type must be :int32/:uint32/:int64/:uint64, :bool, or :string. The value type
- * type must be a Ruby symbol (as accepted by FieldDescriptor#type=) and the
- * type_class must be a string, if present (as accepted by
- * FieldDescriptor#submsg_name=).
- */
-VALUE MessageBuilderContext_map(int argc, VALUE* argv, VALUE _self) {
-  DEFINE_SELF(MessageBuilderContext, self, _self);
-
-  if (argc < 4) {
-    rb_raise(rb_eArgError, "Expected at least 4 arguments.");
-  }
-  VALUE name = argv[0];
-  VALUE key_type = argv[1];
-  VALUE value_type = argv[2];
-  VALUE number = argv[3];
-  VALUE type_class = (argc > 4) ? argv[4] : Qnil;
-
-  // Validate the key type. We can't accept enums, messages, or floats/doubles
-  // as map keys. (We exclude these explicitly, and the field-descriptor setter
-  // below then ensures that the type is one of the remaining valid options.)
-  if (SYM2ID(key_type) == rb_intern("float") ||
-      SYM2ID(key_type) == rb_intern("double") ||
-      SYM2ID(key_type) == rb_intern("enum") ||
-      SYM2ID(key_type) == rb_intern("message")) {
-    rb_raise(rb_eArgError,
-             "Cannot add a map field with a float, double, enum, or message "
-             "type.");
-  }
-
-  // Create a new message descriptor for the map entry message, and create a
-  // repeated submessage field here with that type.
-  VALUE mapentry_desc = rb_class_new_instance(0, NULL, cDescriptor);
-  VALUE mapentry_desc_name = rb_funcall(self->descriptor, rb_intern("name"), 0);
-  mapentry_desc_name = rb_str_cat2(mapentry_desc_name, "_MapEntry_");
-  mapentry_desc_name = rb_str_cat2(mapentry_desc_name,
-                                   rb_id2name(SYM2ID(name)));
-  Descriptor_name_set(mapentry_desc, mapentry_desc_name);
-
-  // The 'mapentry' attribute has no Ruby setter because we do not want the user
-  // attempting to DIY the setup below; we want to ensure that the fields are
-  // correct. So we reach into the msgdef here to set the bit manually.
-  Descriptor* mapentry_desc_self = ruby_to_Descriptor(mapentry_desc);
-  upb_msgdef_setmapentry((upb_msgdef*)mapentry_desc_self->msgdef, true);
-
-  // optional <type> key = 1;
-  VALUE key_field = rb_class_new_instance(0, NULL, cFieldDescriptor);
-  FieldDescriptor_name_set(key_field, rb_str_new2("key"));
-  FieldDescriptor_label_set(key_field, ID2SYM(rb_intern("optional")));
-  FieldDescriptor_number_set(key_field, INT2NUM(1));
-  FieldDescriptor_type_set(key_field, key_type);
-  Descriptor_add_field(mapentry_desc, key_field);
-
-  // optional <type> value = 2;
-  VALUE value_field = rb_class_new_instance(0, NULL, cFieldDescriptor);
-  FieldDescriptor_name_set(value_field, rb_str_new2("value"));
-  FieldDescriptor_label_set(value_field, ID2SYM(rb_intern("optional")));
-  FieldDescriptor_number_set(value_field, INT2NUM(2));
-  FieldDescriptor_type_set(value_field, value_type);
-  if (type_class != Qnil) {
-    VALUE submsg_name = rb_str_new2("."); // prepend '.' to make name absolute.
-    submsg_name = rb_str_append(submsg_name, type_class);
-    FieldDescriptor_submsg_name_set(value_field, submsg_name);
-  }
-  Descriptor_add_field(mapentry_desc, value_field);
-
-  // Add the map-entry message type to the current builder, and use the type to
-  // create the map field itself.
-  Builder* builder_self = ruby_to_Builder(self->builder);
-  rb_ary_push(builder_self->pending_list, mapentry_desc);
-
-  VALUE map_field = rb_class_new_instance(0, NULL, cFieldDescriptor);
-  VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
-  FieldDescriptor_name_set(map_field, name_str);
-  FieldDescriptor_number_set(map_field, number);
-  FieldDescriptor_label_set(map_field, ID2SYM(rb_intern("repeated")));
-  FieldDescriptor_type_set(map_field, ID2SYM(rb_intern("message")));
-  VALUE submsg_name = rb_str_new2("."); // prepend '.' to make name absolute.
-  submsg_name = rb_str_append(submsg_name, mapentry_desc_name);
-  FieldDescriptor_submsg_name_set(map_field, submsg_name);
-  Descriptor_add_field(self->descriptor, map_field);
-
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     MessageBuilderContext.oneof(name, &block) => nil
- *
- * Creates a new OneofDescriptor with the given name, creates a
- * OneofBuilderContext attached to that OneofDescriptor, evaluates the given
- * block in the context of that OneofBuilderContext with #instance_eval, and
- * then adds the oneof to the message.
- *
- * This is the recommended, idiomatic way to build oneof definitions.
- */
-VALUE MessageBuilderContext_oneof(VALUE _self, VALUE name) {
-  DEFINE_SELF(MessageBuilderContext, self, _self);
-  VALUE oneofdef = rb_class_new_instance(0, NULL, cOneofDescriptor);
-  VALUE args[2] = { oneofdef, self->builder };
-  VALUE ctx = rb_class_new_instance(2, args, cOneofBuilderContext);
-  VALUE block = rb_block_proc();
-  VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
-  rb_funcall(oneofdef, rb_intern("name="), 1, name_str);
-  rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  Descriptor_add_oneof(self->descriptor, oneofdef);
-
-  return Qnil;
-}
-
-// -----------------------------------------------------------------------------
-// OneofBuilderContext.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(OneofBuilderContext,
-    "Google::Protobuf::Internal::OneofBuilderContext");
-
-void OneofBuilderContext_mark(void* _self) {
-  OneofBuilderContext* self = _self;
-  rb_gc_mark(self->descriptor);
-  rb_gc_mark(self->builder);
-}
-
-void OneofBuilderContext_free(void* _self) {
-  OneofBuilderContext* self = _self;
-  xfree(self);
-}
-
-VALUE OneofBuilderContext_alloc(VALUE klass) {
-  OneofBuilderContext* self = ALLOC(OneofBuilderContext);
-  VALUE ret = TypedData_Wrap_Struct(
-      klass, &_OneofBuilderContext_type, self);
-  self->descriptor = Qnil;
-  self->builder = Qnil;
-  return ret;
-}
-
-void OneofBuilderContext_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "OneofBuilderContext", rb_cObject);
-  rb_define_alloc_func(klass, OneofBuilderContext_alloc);
-  rb_define_method(klass, "initialize",
-                   OneofBuilderContext_initialize, 2);
-  rb_define_method(klass, "optional", OneofBuilderContext_optional, -1);
-  cOneofBuilderContext = klass;
-  rb_gc_register_address(&cOneofBuilderContext);
-}
-
-/*
- * call-seq:
- *     OneofBuilderContext.new(desc, builder) => context
- *
- * Create a new oneof builder context around the given oneof descriptor and
- * builder context. This class is intended to serve as a DSL context to be used
- * with #instance_eval.
- */
-VALUE OneofBuilderContext_initialize(VALUE _self,
-                                     VALUE oneofdef,
-                                     VALUE builder) {
-  DEFINE_SELF(OneofBuilderContext, self, _self);
-  self->descriptor = oneofdef;
-  self->builder = builder;
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     OneofBuilderContext.optional(name, type, number, type_class = nil)
- *
- * Defines a new optional field in this oneof with the given type, tag number,
- * and type class (for message and enum fields). The type must be a Ruby symbol
- * (as accepted by FieldDescriptor#type=) and the type_class must be a string,
- * if present (as accepted by FieldDescriptor#submsg_name=).
- */
-VALUE OneofBuilderContext_optional(int argc, VALUE* argv, VALUE _self) {
-  DEFINE_SELF(OneofBuilderContext, self, _self);
-
-  if (argc < 3) {
-    rb_raise(rb_eArgError, "Expected at least 3 arguments.");
-  }
-  VALUE name = argv[0];
-  VALUE type = argv[1];
-  VALUE number = argv[2];
-  VALUE type_class = (argc > 3) ? argv[3] : Qnil;
-
-  return msgdef_add_field(self->descriptor, "optional",
-                          name, type, number, type_class);
-}
-
-// -----------------------------------------------------------------------------
-// EnumBuilderContext.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(EnumBuilderContext,
-    "Google::Protobuf::Internal::EnumBuilderContext");
-
-void EnumBuilderContext_mark(void* _self) {
-  EnumBuilderContext* self = _self;
-  rb_gc_mark(self->enumdesc);
-}
-
-void EnumBuilderContext_free(void* _self) {
-  EnumBuilderContext* self = _self;
-  xfree(self);
-}
-
-VALUE EnumBuilderContext_alloc(VALUE klass) {
-  EnumBuilderContext* self = ALLOC(EnumBuilderContext);
-  VALUE ret = TypedData_Wrap_Struct(
-      klass, &_EnumBuilderContext_type, self);
-  self->enumdesc = Qnil;
-  return ret;
-}
-
-void EnumBuilderContext_register(VALUE module) {
-  VALUE klass = rb_define_class_under(
-      module, "EnumBuilderContext", rb_cObject);
-  rb_define_alloc_func(klass, EnumBuilderContext_alloc);
-  rb_define_method(klass, "initialize",
-                   EnumBuilderContext_initialize, 1);
-  rb_define_method(klass, "value", EnumBuilderContext_value, 2);
-  cEnumBuilderContext = klass;
-  rb_gc_register_address(&cEnumBuilderContext);
-}
-
-/*
- * call-seq:
- *     EnumBuilderContext.new(enumdesc) => context
- *
- * Create a new builder context around the given enum descriptor. This class is
- * intended to serve as a DSL context to be used with #instance_eval.
- */
-VALUE EnumBuilderContext_initialize(VALUE _self, VALUE enumdef) {
-  DEFINE_SELF(EnumBuilderContext, self, _self);
-  self->enumdesc = enumdef;
-  return Qnil;
-}
-
-static VALUE enumdef_add_value(VALUE enumdef,
-                               VALUE name, VALUE number) {
-  rb_funcall(enumdef, rb_intern("add_value"), 2, name, number);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     EnumBuilder.add_value(name, number)
- *
- * Adds the given name => number mapping to the enum type. Name must be a Ruby
- * symbol.
- */
-VALUE EnumBuilderContext_value(VALUE _self, VALUE name, VALUE number) {
-  DEFINE_SELF(EnumBuilderContext, self, _self);
-  return enumdef_add_value(self->enumdesc, name, number);
-}
-
-// -----------------------------------------------------------------------------
-// Builder.
-// -----------------------------------------------------------------------------
-
-DEFINE_CLASS(Builder, "Google::Protobuf::Internal::Builder");
-
-void Builder_mark(void* _self) {
-  Builder* self = _self;
-  rb_gc_mark(self->pending_list);
-}
-
-void Builder_free(void* _self) {
-  Builder* self = _self;
-  xfree(self->defs);
-  xfree(self);
-}
-
-/*
- * call-seq:
- *     Builder.new => builder
- *
- * Creates a new Builder. A Builder can accumulate a set of new message and enum
- * descriptors and atomically register them into a pool in a way that allows for
- * (co)recursive type references.
- */
-VALUE Builder_alloc(VALUE klass) {
-  Builder* self = ALLOC(Builder);
-  VALUE ret = TypedData_Wrap_Struct(
-      klass, &_Builder_type, self);
-  self->pending_list = rb_ary_new();
-  self->defs = NULL;
-  return ret;
-}
-
-void Builder_register(VALUE module) {
-  VALUE klass = rb_define_class_under(module, "Builder", rb_cObject);
-  rb_define_alloc_func(klass, Builder_alloc);
-  rb_define_method(klass, "add_message", Builder_add_message, 1);
-  rb_define_method(klass, "add_enum", Builder_add_enum, 1);
-  rb_define_method(klass, "finalize_to_pool", Builder_finalize_to_pool, 1);
-  cBuilder = klass;
-  rb_gc_register_address(&cBuilder);
-}
-
-/*
- * call-seq:
- *     Builder.add_message(name, &block)
- *
- * Creates a new, empty descriptor with the given name, and invokes the block in
- * the context of a MessageBuilderContext on that descriptor. The block can then
- * call, e.g., MessageBuilderContext#optional and MessageBuilderContext#repeated
- * methods to define the message fields.
- *
- * This is the recommended, idiomatic way to build message definitions.
- */
-VALUE Builder_add_message(VALUE _self, VALUE name) {
-  DEFINE_SELF(Builder, self, _self);
-  VALUE msgdef = rb_class_new_instance(0, NULL, cDescriptor);
-  VALUE args[2] = { msgdef, _self };
-  VALUE ctx = rb_class_new_instance(2, args, cMessageBuilderContext);
-  VALUE block = rb_block_proc();
-  rb_funcall(msgdef, rb_intern("name="), 1, name);
-  rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_ary_push(self->pending_list, msgdef);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Builder.add_enum(name, &block)
- *
- * Creates a new, empty enum descriptor with the given name, and invokes the
- * block in the context of an EnumBuilderContext on that descriptor. The block
- * can then call EnumBuilderContext#add_value to define the enum values.
- *
- * This is the recommended, idiomatic way to build enum definitions.
- */
-VALUE Builder_add_enum(VALUE _self, VALUE name) {
-  DEFINE_SELF(Builder, self, _self);
-  VALUE enumdef = rb_class_new_instance(0, NULL, cEnumDescriptor);
-  VALUE ctx = rb_class_new_instance(1, &enumdef, cEnumBuilderContext);
-  VALUE block = rb_block_proc();
-  rb_funcall(enumdef, rb_intern("name="), 1, name);
-  rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_ary_push(self->pending_list, enumdef);
-  return Qnil;
-}
-
-static void validate_msgdef(const upb_msgdef* msgdef) {
-  // Verify that no required fields exist. proto3 does not support these.
-  upb_msg_field_iter it;
-  for (upb_msg_field_begin(&it, msgdef);
-       !upb_msg_field_done(&it);
-       upb_msg_field_next(&it)) {
-    const upb_fielddef* field = upb_msg_iter_field(&it);
-    if (upb_fielddef_label(field) == UPB_LABEL_REQUIRED) {
-      rb_raise(rb_eTypeError, "Required fields are unsupported in proto3.");
-    }
-  }
-}
-
-static void validate_enumdef(const upb_enumdef* enumdef) {
-  // Verify that an entry exists with integer value 0. (This is the default
-  // value.)
-  const char* lookup = upb_enumdef_iton(enumdef, 0);
-  if (lookup == NULL) {
-    rb_raise(rb_eTypeError,
-             "Enum definition does not contain a value for '0'.");
-  }
-}
-
-/*
- * call-seq:
- *     Builder.finalize_to_pool(pool)
- *
- * Adds all accumulated message and enum descriptors created in this builder
- * context to the given pool. The operation occurs atomically, and all
- * descriptors can refer to each other (including in cycles). This is the only
- * way to build (co)recursive message definitions.
- *
- * This method is usually called automatically by DescriptorPool#build after it
- * invokes the given user block in the context of the builder. The user should
- * not normally need to call this manually because a Builder is not normally
- * created manually.
- */
-VALUE Builder_finalize_to_pool(VALUE _self, VALUE pool_rb) {
-  DEFINE_SELF(Builder, self, _self);
-
-  DescriptorPool* pool = ruby_to_DescriptorPool(pool_rb);
-
-  REALLOC_N(self->defs, upb_def*, RARRAY_LEN(self->pending_list));
-
-  for (int i = 0; i < RARRAY_LEN(self->pending_list); i++) {
-    VALUE def_rb = rb_ary_entry(self->pending_list, i);
-    if (CLASS_OF(def_rb) == cDescriptor) {
-      self->defs[i] = (upb_def*)ruby_to_Descriptor(def_rb)->msgdef;
-      validate_msgdef((const upb_msgdef*)self->defs[i]);
-    } else if (CLASS_OF(def_rb) == cEnumDescriptor) {
-      self->defs[i] = (upb_def*)ruby_to_EnumDescriptor(def_rb)->enumdef;
-      validate_enumdef((const upb_enumdef*)self->defs[i]);
-    }
-  }
-
-  CHECK_UPB(upb_symtab_add(pool->symtab, (upb_def**)self->defs,
-                           RARRAY_LEN(self->pending_list), NULL, &status),
-            "Unable to add defs to DescriptorPool");
-
-  for (int i = 0; i < RARRAY_LEN(self->pending_list); i++) {
-    VALUE def_rb = rb_ary_entry(self->pending_list, i);
-    add_def_obj(self->defs[i], def_rb);
-  }
-
-  self->pending_list = rb_ary_new();
-  return Qnil;
-}