Remove `Arena_pin` in favor of adopting the UPB freezing API.

PiperOrigin-RevId: 639960700

ruby/ext/google/protobuf_c/map.c

@@ -63,8 +63,8 @@ static VALUE Map_alloc(VALUE klass) {
   return TypedData_Wrap_Struct(klass, &Map_type, self);
 }
 
-VALUE Map_GetRubyWrapper(upb_Map* map, upb_CType key_type, TypeInfo value_type,
+VALUE Map_GetRubyWrapper(const upb_Map* map, upb_CType key_type,
-                         VALUE arena) {
+                         TypeInfo value_type, VALUE arena) {
   PBRUBY_ASSERT(map);
 
   VALUE val = ObjectCache_Get(map);
@@ -83,7 +83,6 @@ VALUE Map_GetRubyWrapper(upb_Map* map, upb_CType key_type, TypeInfo value_type,
     }
     return ObjectCache_TryAdd(map, val);
   }
-
   return val;
 }
 
@@ -105,8 +104,9 @@ static TypeInfo Map_keyinfo(Map* self) {
 }
 
 static upb_Map* Map_GetMutable(VALUE _self) {
-  rb_check_frozen(_self);
+  const upb_Map* map = ruby_to_Map(_self)->map;
-  return (upb_Map*)ruby_to_Map(_self)->map;
+  Protobuf_CheckNotFrozen(_self, upb_Map_IsFrozen(map));
+  return (upb_Map*)map;
 }
 
 VALUE Map_CreateHash(const upb_Map* map, upb_CType key_type,
@@ -439,14 +439,14 @@ static VALUE Map_has_key(VALUE _self, VALUE key) {
  * nil if none was present. Throws an exception if the key is of the wrong type.
  */
 static VALUE Map_delete(VALUE _self, VALUE key) {
+  upb_Map* map = Map_GetMutable(_self);
   Map* self = ruby_to_Map(_self);
-  rb_check_frozen(_self);
 
   upb_MessageValue key_upb =
       Convert_RubyToUpb(key, "", Map_keyinfo(self), NULL);
   upb_MessageValue val_upb;
 
-  if (upb_Map_Delete(Map_GetMutable(_self), key_upb, &val_upb)) {
+  if (upb_Map_Delete(map, key_upb, &val_upb)) {
     return Convert_UpbToRuby(val_upb, self->value_type_info, self->arena);
   } else {
     return Qnil;
@@ -560,29 +560,79 @@ VALUE Map_eq(VALUE _self, VALUE _other) {
 
 /*
  * call-seq:
- *     Message.freeze => self
+ *     Map.frozen? => bool
+ *
+ * Returns true if the map is frozen in either Ruby or the underlying
+ * representation. Freezes the Ruby map object if it is not already frozen in
+ * Ruby but it is frozen in the underlying representation.
+ */
+VALUE Map_frozen(VALUE _self) {
+  Map* self = ruby_to_Map(_self);
+  if (!upb_Map_IsFrozen(self->map)) {
+    PBRUBY_ASSERT(!RB_OBJ_FROZEN(_self));
+    return Qfalse;
+  }
+
+  // Lazily freeze the Ruby wrapper.
+  if (!RB_OBJ_FROZEN(_self)) RB_OBJ_FREEZE(_self);
+  return Qtrue;
+}
+
+/*
+ * call-seq:
+ *     Map.freeze => self
  *
- * Freezes the message object. We have to intercept this so we can pin the
+ * Freezes the map object. We have to intercept this so we can freeze the
- * Ruby object into memory so we don't forget it's frozen.
+ * underlying representation, not just the Ruby wrapper.
  */
 VALUE Map_freeze(VALUE _self) {
   Map* self = ruby_to_Map(_self);
+  if (RB_OBJ_FROZEN(_self)) {
+    PBRUBY_ASSERT(upb_Map_IsFrozen(self->map));
+    return _self;
+  }
+
+  if (!upb_Map_IsFrozen(self->map)) {
+    if (self->value_type_info.type == kUpb_CType_Message) {
+      upb_Map_Freeze(
+          Map_GetMutable(_self),
+          upb_MessageDef_MiniTable(self->value_type_info.def.msgdef));
+    } else {
+      upb_Map_Freeze(Map_GetMutable(_self), NULL);
+    }
+  }
 
-  if (RB_OBJ_FROZEN(_self)) return _self;
-  Arena_Pin(self->arena, _self);
   RB_OBJ_FREEZE(_self);
 
-  if (self->value_type_info.type == kUpb_CType_Message) {
+  return _self;
-    size_t iter = kUpb_Map_Begin;
+}
-    upb_MessageValue key, val;
+
+VALUE Map_EmptyFrozen(const upb_FieldDef* f) {
+  PBRUBY_ASSERT(upb_FieldDef_IsMap(f));
+  VALUE val = ObjectCache_Get(f);
 
-    while (upb_Map_Next(self->map, &key, &val, &iter)) {
+  if (val == Qnil) {
-      VALUE val_val =
+    const upb_FieldDef* key_f = map_field_key(f);
-          Convert_UpbToRuby(val, self->value_type_info, self->arena);
+    const upb_FieldDef* val_f = map_field_value(f);
-      Message_freeze(val_val);
+    upb_CType key_type = upb_FieldDef_CType(key_f);
+    TypeInfo value_type_info = TypeInfo_get(val_f);
+    val = Map_alloc(cMap);
+    Map* self;
+    TypedData_Get_Struct(val, Map, &Map_type, self);
+    self->arena = Arena_new();
+    self->map =
+        upb_Map_New(Arena_get(self->arena), key_type, value_type_info.type);
+    self->key_type = key_type;
+    self->value_type_info = value_type_info;
+    if (self->value_type_info.type == kUpb_CType_Message) {
+      const upb_MessageDef* val_m = value_type_info.def.msgdef;
+      self->value_type_class = Descriptor_DefToClass(val_m);
     }
+    return ObjectCache_TryAdd(f, Map_freeze(val));
   }
-  return _self;
+  PBRUBY_ASSERT(RB_OBJ_FROZEN(val));
+  PBRUBY_ASSERT(upb_Map_IsFrozen(ruby_to_Map(val)->map));
+  return val;
 }
 
 /*
@@ -671,6 +721,7 @@ void Map_register(VALUE module) {
   rb_define_method(klass, "clone", Map_dup, 0);
   rb_define_method(klass, "==", Map_eq, 1);
   rb_define_method(klass, "freeze", Map_freeze, 0);
+  rb_define_method(klass, "frozen?", Map_frozen, 0);
   rb_define_method(klass, "hash", Map_hash, 0);
   rb_define_method(klass, "to_h", Map_to_h, 0);
   rb_define_method(klass, "inspect", Map_inspect, 0);

ruby/ext/google/protobuf_c/map.h

@@ -11,10 +11,14 @@
 #include "protobuf.h"
 #include "ruby-upb.h"
 
+// Returns a frozen sentinel Ruby wrapper object for an empty upb_Map with the
+// key and value types specified by the field. Creates one if it doesn't exist.
+VALUE Map_EmptyFrozen(const upb_FieldDef* f);
+
 // Returns a Ruby wrapper object for the given map, which will be created if
 // one does not exist already.
-VALUE Map_GetRubyWrapper(upb_Map *map, upb_CType key_type, TypeInfo value_type,
+VALUE Map_GetRubyWrapper(const upb_Map *map, upb_CType key_type,
-                         VALUE arena);
+                         TypeInfo value_type, VALUE arena);
 
 // Gets the underlying upb_Map for this Ruby map object, which must have
 // key/value type that match |field|. If this is not a map or the type doesn't

ruby/ext/google/protobuf_c/message.c

@@ -80,11 +80,12 @@ const upb_Message* Message_Get(VALUE msg_rb, const upb_MessageDef** m) {
 }
 
 upb_Message* Message_GetMutable(VALUE msg_rb, const upb_MessageDef** m) {
-  rb_check_frozen(msg_rb);
+  const upb_Message* upb_msg = Message_Get(msg_rb, m);
-  return (upb_Message*)Message_Get(msg_rb, m);
+  Protobuf_CheckNotFrozen(msg_rb, upb_Message_IsFrozen(upb_msg));
+  return (upb_Message*)upb_msg;
 }
 
-void Message_InitPtr(VALUE self_, upb_Message* msg, VALUE arena) {
+void Message_InitPtr(VALUE self_, const upb_Message* msg, VALUE arena) {
   Message* self = ruby_to_Message(self_);
   self->msg = msg;
   RB_OBJ_WRITE(self_, &self->arena, arena);
@@ -105,7 +106,7 @@ void Message_CheckClass(VALUE klass) {
   }
 }
 
-VALUE Message_GetRubyWrapper(upb_Message* msg, const upb_MessageDef* m,
+VALUE Message_GetRubyWrapper(const upb_Message* msg, const upb_MessageDef* m,
                              VALUE arena) {
   if (msg == NULL) return Qnil;
 
@@ -116,7 +117,6 @@ VALUE Message_GetRubyWrapper(upb_Message* msg, const upb_MessageDef* m,
     val = Message_alloc(klass);
     Message_InitPtr(val, msg, arena);
   }
-
   return val;
 }
 
@@ -288,13 +288,42 @@ static void Message_setfield(upb_Message* msg, const upb_FieldDef* f, VALUE val,
   upb_Message_SetFieldByDef(msg, f, msgval, arena);
 }
 
+VALUE Message_getfield_frozen(const upb_Message* msg, const upb_FieldDef* f,
+                              VALUE arena) {
+  upb_MessageValue msgval = upb_Message_GetFieldByDef(msg, f);
+  if (upb_FieldDef_IsMap(f)) {
+    if (msgval.map_val == NULL) {
+      return Map_EmptyFrozen(f);
+    }
+    const upb_FieldDef* key_f = map_field_key(f);
+    const upb_FieldDef* val_f = map_field_value(f);
+    upb_CType key_type = upb_FieldDef_CType(key_f);
+    TypeInfo value_type_info = TypeInfo_get(val_f);
+    return Map_GetRubyWrapper(msgval.map_val, key_type, value_type_info, Qnil);
+  }
+  if (upb_FieldDef_IsRepeated(f)) {
+    if (msgval.array_val == NULL) {
+      return RepeatedField_EmptyFrozen(f);
+    }
+    return RepeatedField_GetRubyWrapper(msgval.array_val, TypeInfo_get(f),
+                                        Qnil);
+  }
+  VALUE ret;
+  if (upb_FieldDef_IsSubMessage(f)) {
+    const upb_MessageDef* m = upb_FieldDef_MessageSubDef(f);
+    ret = Message_GetRubyWrapper(msgval.msg_val, m, arena);
+  } else {
+    ret = Convert_UpbToRuby(msgval, TypeInfo_get(f), Qnil);
+  }
+  return ret;
+}
+
 VALUE Message_getfield(VALUE _self, const upb_FieldDef* f) {
   Message* self = ruby_to_Message(_self);
-  // This is a special-case: upb_Message_Mutable() for map & array are logically
+  if (upb_Message_IsFrozen(self->msg)) {
-  // const (they will not change what is serialized) but physically
+    return Message_getfield_frozen(self->msg, f, self->arena);
-  // non-const, as they do allocate a repeated field or map. The logical
+  }
-  // constness means it's ok to do even if the message is frozen.
+  upb_Message* msg = Message_GetMutable(_self, NULL);
-  upb_Message* msg = (upb_Message*)self->msg;
   upb_Arena* arena = Arena_get(self->arena);
   if (upb_FieldDef_IsMap(f)) {
     upb_Map* map = upb_Message_Mutable(msg, f, arena).map;
@@ -307,12 +336,12 @@ VALUE Message_getfield(VALUE _self, const upb_FieldDef* f) {
     upb_Array* arr = upb_Message_Mutable(msg, f, arena).array;
     return RepeatedField_GetRubyWrapper(arr, TypeInfo_get(f), self->arena);
   } else if (upb_FieldDef_IsSubMessage(f)) {
-    if (!upb_Message_HasFieldByDef(self->msg, f)) return Qnil;
+    if (!upb_Message_HasFieldByDef(msg, f)) return Qnil;
     upb_Message* submsg = upb_Message_Mutable(msg, f, arena).msg;
     const upb_MessageDef* m = upb_FieldDef_MessageSubDef(f);
     return Message_GetRubyWrapper(submsg, m, self->arena);
   } else {
-    upb_MessageValue msgval = upb_Message_GetFieldByDef(self->msg, f);
+    upb_MessageValue msgval = upb_Message_GetFieldByDef(msg, f);
     return Convert_UpbToRuby(msgval, TypeInfo_get(f), self->arena);
   }
 }
@@ -436,7 +465,6 @@ static VALUE Message_method_missing(int argc, VALUE* argv, VALUE _self) {
       if (argc != 2) {
         rb_raise(rb_eArgError, "Expected 2 arguments, received %d", argc);
       }
-      rb_check_frozen(_self);
       break;
     default:
       if (argc != 1) {
@@ -812,33 +840,42 @@ static VALUE Message_to_h(VALUE _self) {
 
 /*
  * call-seq:
- *     Message.freeze => self
+ *     Message.frozen? => bool
  *
- * Freezes the message object. We have to intercept this so we can pin the
+ * Returns true if the message is frozen in either Ruby or the underlying
- * Ruby object into memory so we don't forget it's frozen.
+ * representation. Freezes the Ruby message object if it is not already frozen
+ * in Ruby but it is frozen in the underlying representation.
  */
-VALUE Message_freeze(VALUE _self) {
+VALUE Message_frozen(VALUE _self) {
   Message* self = ruby_to_Message(_self);
+  if (!upb_Message_IsFrozen(self->msg)) {
+    PBRUBY_ASSERT(!RB_OBJ_FROZEN(_self));
+    return Qfalse;
+  }
 
-  if (RB_OBJ_FROZEN(_self)) return _self;
+  // Lazily freeze the Ruby wrapper.
-  Arena_Pin(self->arena, _self);
+  if (!RB_OBJ_FROZEN(_self)) RB_OBJ_FREEZE(_self);
-  RB_OBJ_FREEZE(_self);
+  return Qtrue;
+}
 
-  int n = upb_MessageDef_FieldCount(self->msgdef);
+/*
-  for (int i = 0; i < n; i++) {
+ * call-seq:
-    const upb_FieldDef* f = upb_MessageDef_Field(self->msgdef, i);
+ *     Message.freeze => self
-    VALUE field = Message_getfield(_self, f);
+ *
-
+ * Freezes the message object. We have to intercept this so we can freeze the
-    if (field != Qnil) {
+ * underlying representation, not just the Ruby wrapper.
-      if (upb_FieldDef_IsMap(f)) {
+ */
-        Map_freeze(field);
+VALUE Message_freeze(VALUE _self) {
-      } else if (upb_FieldDef_IsRepeated(f)) {
+  Message* self = ruby_to_Message(_self);
-        RepeatedField_freeze(field);
+  if (RB_OBJ_FROZEN(_self)) {
-      } else if (upb_FieldDef_IsSubMessage(f)) {
+    PBRUBY_ASSERT(upb_Message_IsFrozen(self->msg));
-        Message_freeze(field);
+    return _self;
-      }
-    }
   }
+  if (!upb_Message_IsFrozen(self->msg)) {
+    upb_Message_Freeze(Message_GetMutable(_self, NULL),
+                       upb_MessageDef_MiniTable(self->msgdef));
+  }
+  RB_OBJ_FREEZE(_self);
   return _self;
 }
 
@@ -1352,6 +1389,7 @@ static void Message_define_class(VALUE klass) {
   rb_define_method(klass, "==", Message_eq, 1);
   rb_define_method(klass, "eql?", Message_eq, 1);
   rb_define_method(klass, "freeze", Message_freeze, 0);
+  rb_define_method(klass, "frozen?", Message_frozen, 0);
   rb_define_method(klass, "hash", Message_hash, 0);
   rb_define_method(klass, "to_h", Message_to_h, 0);
   rb_define_method(klass, "inspect", Message_inspect, 0);

ruby/ext/google/protobuf_c/message.h

@@ -36,7 +36,7 @@ const upb_Message* Message_GetUpbMessage(VALUE value, const upb_MessageDef* m,
 
 // Gets or constructs a Ruby wrapper object for the given message. The wrapper
 // object will reference |arena| and ensure that it outlives this object.
-VALUE Message_GetRubyWrapper(upb_Message* msg, const upb_MessageDef* m,
+VALUE Message_GetRubyWrapper(const upb_Message* msg, const upb_MessageDef* m,
                              VALUE arena);
 
 // Gets the given field from this message.

ruby/ext/google/protobuf_c/protobuf.c

@@ -221,15 +221,6 @@ void Arena_fuse(VALUE _arena, upb_Arena *other) {
 
 VALUE Arena_new() { return Arena_alloc(cArena); }
 
-void Arena_Pin(VALUE _arena, VALUE obj) {
-  Arena *arena;
-  TypedData_Get_Struct(_arena, Arena, &Arena_type, arena);
-  if (arena->pinned_objs == Qnil) {
-    RB_OBJ_WRITE(_arena, &arena->pinned_objs, rb_ary_new());
-  }
-  rb_ary_push(arena->pinned_objs, obj);
-}
-
 void Arena_register(VALUE module) {
   VALUE internal = rb_define_module_under(module, "Internal");
   VALUE klass = rb_define_class_under(internal, "Arena", rb_cObject);
@@ -354,3 +345,14 @@ __attribute__((visibility("default"))) void Init_protobuf_c() {
   rb_define_singleton_method(protobuf, "deep_copy", Google_Protobuf_deep_copy,
                              1);
 }
+
+// -----------------------------------------------------------------------------
+// Utilities
+// -----------------------------------------------------------------------------
+
+// Raises a Ruby error if val is frozen in Ruby or UPB.
+void Protobuf_CheckNotFrozen(VALUE val, bool upb_frozen) {
+  if (RB_UNLIKELY(rb_obj_frozen_p(val)||upb_frozen)) {
+    rb_error_frozen_object(val);
+  }
+}

ruby/ext/google/protobuf_c/protobuf.h

@@ -50,13 +50,6 @@ upb_Arena* Arena_get(VALUE arena);
 // possible.
 void Arena_fuse(VALUE arena, upb_Arena* other);
 
-// Pins this Ruby object to the lifetime of this arena, so that as long as the
-// arena is alive this object will not be collected.
-//
-// We use this to guarantee that the "frozen" bit on the object will be
-// remembered, even if the user drops their reference to this precise object.
-void Arena_Pin(VALUE arena, VALUE obj);
-
 // -----------------------------------------------------------------------------
 // ObjectCache
 // -----------------------------------------------------------------------------
@@ -105,6 +98,9 @@ extern VALUE cTypeError;
   rb_bug("Assertion failed at %s:%d, expr: %s", __FILE__, __LINE__, #expr)
 #endif
 
+// Raises a Ruby error if val is frozen in Ruby or upb_frozen is true.
+void Protobuf_CheckNotFrozen(VALUE val, bool upb_frozen);
+
 #define PBRUBY_MAX(x, y) (((x) > (y)) ? (x) : (y))
 
 #define UPB_UNUSED(var) (void)var

ruby/ext/google/protobuf_c/repeated_field.c

@@ -44,8 +44,9 @@ static RepeatedField* ruby_to_RepeatedField(VALUE _self) {
 }
 
 static upb_Array* RepeatedField_GetMutable(VALUE _self) {
-  rb_check_frozen(_self);
+  const upb_Array* array = ruby_to_RepeatedField(_self)->array;
-  return (upb_Array*)ruby_to_RepeatedField(_self)->array;
+  Protobuf_CheckNotFrozen(_self, upb_Array_IsFrozen(array));
+  return (upb_Array*)array;
 }
 
 VALUE RepeatedField_alloc(VALUE klass) {
@@ -56,7 +57,29 @@ VALUE RepeatedField_alloc(VALUE klass) {
   return TypedData_Wrap_Struct(klass, &RepeatedField_type, self);
 }
 
-VALUE RepeatedField_GetRubyWrapper(upb_Array* array, TypeInfo type_info,
+VALUE RepeatedField_EmptyFrozen(const upb_FieldDef* f) {
+  PBRUBY_ASSERT(upb_FieldDef_IsRepeated(f));
+  VALUE val = ObjectCache_Get(f);
+
+  if (val == Qnil) {
+    val = RepeatedField_alloc(cRepeatedField);
+    RepeatedField* self;
+    TypedData_Get_Struct(val, RepeatedField, &RepeatedField_type, self);
+    self->arena = Arena_new();
+    TypeInfo type_info = TypeInfo_get(f);
+    self->array = upb_Array_New(Arena_get(self->arena), type_info.type);
+    self->type_info = type_info;
+    if (self->type_info.type == kUpb_CType_Message) {
+      self->type_class = Descriptor_DefToClass(type_info.def.msgdef);
+    }
+    val = ObjectCache_TryAdd(f, RepeatedField_freeze(val));
+  }
+  PBRUBY_ASSERT(RB_OBJ_FROZEN(val));
+  PBRUBY_ASSERT(upb_Array_IsFrozen(ruby_to_RepeatedField(val)->array));
+  return val;
+}
+
+VALUE RepeatedField_GetRubyWrapper(const upb_Array* array, TypeInfo type_info,
                                    VALUE arena) {
   PBRUBY_ASSERT(array);
   VALUE val = ObjectCache_Get(array);
@@ -78,7 +101,6 @@ VALUE RepeatedField_GetRubyWrapper(upb_Array* array, TypeInfo type_info,
   PBRUBY_ASSERT(ruby_to_RepeatedField(val)->type_info.def.msgdef ==
                 type_info.def.msgdef);
   PBRUBY_ASSERT(ruby_to_RepeatedField(val)->array == array);
-
   return val;
 }
 
@@ -471,29 +493,49 @@ VALUE RepeatedField_eq(VALUE _self, VALUE _other) {
   return Qtrue;
 }
 
+/*
+ * call-seq:
+ *     RepeatedField.frozen? => bool
+ *
+ * Returns true if the repeated field is frozen in either Ruby or the underlying
+ * representation. Freezes the Ruby repeated field object if it is not already
+ * frozen in Ruby but it is frozen in the underlying representation.
+ */
+VALUE RepeatedField_frozen(VALUE _self) {
+  RepeatedField* self = ruby_to_RepeatedField(_self);
+  if (!upb_Array_IsFrozen(self->array)) {
+    PBRUBY_ASSERT(!RB_OBJ_FROZEN(_self));
+    return Qfalse;
+  }
+
+  // Lazily freeze the Ruby wrapper.
+  if (!RB_OBJ_FROZEN(_self)) RB_OBJ_FREEZE(_self);
+  return Qtrue;
+}
+
 /*
  * call-seq:
  *     RepeatedField.freeze => self
  *
- * Freezes the repeated field. We have to intercept this so we can pin the Ruby
+ * Freezes the repeated field object. We have to intercept this so we can freeze
- * object into memory so we don't forget it's frozen.
+ * the underlying representation, not just the Ruby wrapper.
  */
 VALUE RepeatedField_freeze(VALUE _self) {
   RepeatedField* self = ruby_to_RepeatedField(_self);
+  if (RB_OBJ_FROZEN(_self)) {
+    PBRUBY_ASSERT(upb_Array_IsFrozen(self->array));
+    return _self;
+  }
 
-  if (RB_OBJ_FROZEN(_self)) return _self;
+  if (!upb_Array_IsFrozen(self->array)) {
-  Arena_Pin(self->arena, _self);
+    if (self->type_info.type == kUpb_CType_Message) {
-  RB_OBJ_FREEZE(_self);
+      upb_Array_Freeze(RepeatedField_GetMutable(_self),
-
+                       upb_MessageDef_MiniTable(self->type_info.def.msgdef));
-  if (self->type_info.type == kUpb_CType_Message) {
+    } else {
-    int size = upb_Array_Size(self->array);
+      upb_Array_Freeze(RepeatedField_GetMutable(_self), NULL);
-    int i;
-    for (i = 0; i < size; i++) {
-      upb_MessageValue msgval = upb_Array_Get(self->array, i);
-      VALUE val = Convert_UpbToRuby(msgval, self->type_info, self->arena);
-      Message_freeze(val);
     }
   }
+  RB_OBJ_FREEZE(_self);
   return _self;
 }
 
@@ -640,6 +682,7 @@ void RepeatedField_register(VALUE module) {
   rb_define_method(klass, "==", RepeatedField_eq, 1);
   rb_define_method(klass, "to_ary", RepeatedField_to_ary, 0);
   rb_define_method(klass, "freeze", RepeatedField_freeze, 0);
+  rb_define_method(klass, "frozen?", RepeatedField_frozen, 0);
   rb_define_method(klass, "hash", RepeatedField_hash, 0);
   rb_define_method(klass, "+", RepeatedField_plus, 1);
   rb_define_method(klass, "concat", RepeatedField_concat, 1);

ruby/ext/google/protobuf_c/repeated_field.h

@@ -11,9 +11,13 @@
 #include "protobuf.h"
 #include "ruby-upb.h"
 
+// Returns a frozen sentinel Ruby wrapper object for an empty upb_Array of the
+// type specified by the field. Creates one if it doesn't exist.
+VALUE RepeatedField_EmptyFrozen(const upb_FieldDef* f);
+
 // Returns a Ruby wrapper object for the given upb_Array, which will be created
 // if one does not exist already.
-VALUE RepeatedField_GetRubyWrapper(upb_Array* msg, TypeInfo type_info,
+VALUE RepeatedField_GetRubyWrapper(const upb_Array* msg, TypeInfo type_info,
                                    VALUE arena);
 
 // Gets the underlying upb_Array for this Ruby RepeatedField object, which must

ruby/lib/google/protobuf/ffi/descriptor.rb

@@ -140,7 +140,6 @@ module Google
         message = OBJECT_CACHE.get(msg.address)
         if message.nil?
           message = descriptor.msgclass.send(:private_constructor, arena, msg: msg)
-          message.freeze if frozen?
         end
         message
       end

ruby/lib/google/protobuf/ffi/internal/arena.rb

@@ -12,8 +12,6 @@ module Google
   module Protobuf
     module Internal
       class Arena
-        attr :pinned_messages
-
         # FFI Interface methods and setup
         extend ::FFI::DataConverter
         native_type ::FFI::Type::POINTER
@@ -46,10 +44,6 @@ module Google
             raise RuntimeError.new "Unable to fuse arenas. This should never happen since Ruby does not use initial blocks"
           end
         end
-
-        def pin(message)
-          pinned_messages.push message
-        end
       end
     end
 

ruby/lib/google/protobuf/ffi/map.rb

@@ -9,18 +9,20 @@ module Google
   module Protobuf
     class FFI
       # Map
-      attach_function :map_clear,  :upb_Map_Clear,                    [:Map], :void
+      attach_function :map_clear,   :upb_Map_Clear,         [:Map], :void
-      attach_function :map_delete, :upb_Map_Delete,                   [:Map, MessageValue.by_value, MessageValue.by_ref], :bool
+      attach_function :map_delete,  :upb_Map_Delete,        [:Map, MessageValue.by_value, MessageValue.by_ref], :bool
-      attach_function :map_get,    :upb_Map_Get,                      [:Map, MessageValue.by_value, MessageValue.by_ref], :bool
+      attach_function :map_get,     :upb_Map_Get,           [:Map, MessageValue.by_value, MessageValue.by_ref], :bool
-      attach_function :create_map, :upb_Map_New,                      [Internal::Arena, CType, CType], :Map
+      attach_function :create_map,  :upb_Map_New,           [Internal::Arena, CType, CType], :Map
-      attach_function :map_size,   :upb_Map_Size,                     [:Map], :size_t
+      attach_function :map_size,    :upb_Map_Size,          [:Map], :size_t
-      attach_function :map_set,    :upb_Map_Set,                      [:Map, MessageValue.by_value, MessageValue.by_value, Internal::Arena], :bool
+      attach_function :map_set,     :upb_Map_Set,           [:Map, MessageValue.by_value, MessageValue.by_value, Internal::Arena], :bool
+      attach_function :map_freeze,  :upb_Map_Freeze,        [:Map, MiniTable.by_ref], :void
+      attach_function :map_frozen?, :upb_Map_IsFrozen,      [:Map], :bool
 
       # MapIterator
-      attach_function :map_next,   :upb_MapIterator_Next,             [:Map, :pointer], :bool
+      attach_function :map_next,    :upb_MapIterator_Next,  [:Map, :pointer], :bool
-      attach_function :map_done,   :upb_MapIterator_Done,             [:Map, :size_t], :bool
+      attach_function :map_done,    :upb_MapIterator_Done,  [:Map, :size_t], :bool
-      attach_function :map_key,    :upb_MapIterator_Key,              [:Map, :size_t], MessageValue.by_value
+      attach_function :map_key,     :upb_MapIterator_Key,   [:Map, :size_t], MessageValue.by_value
-      attach_function :map_value,  :upb_MapIterator_Value,            [:Map, :size_t], MessageValue.by_value
+      attach_function :map_value,   :upb_MapIterator_Value, [:Map, :size_t], MessageValue.by_value
     end
     class Map
       include Enumerable
@@ -155,17 +157,35 @@ module Google
       end
       alias size length
 
+      ##
+      # Is this object frozen?
+      # Returns true if either this Ruby wrapper or the underlying
+      # representation are frozen. Freezes the wrapper if the underlying
+      # representation is already frozen but this wrapper isn't.
+      def frozen?
+        unless Google::Protobuf::FFI.map_frozen? @map_ptr
+          raise RuntimeError.new "Ruby frozen Map with mutable representation" if super
+          return false
+        end
+        method(:freeze).super_method.call unless super
+        true
+      end
+
+      ##
+      # Freezes the map object. We have to intercept this so we can freeze the
+      # underlying representation, not just the Ruby wrapper. Returns self.
       def freeze
-        return self if frozen?
+        if method(:frozen?).super_method.call
-        super
+          unless Google::Protobuf::FFI.map_frozen? @map_ptr
-        @arena.pin self
+            raise RuntimeError.new "Underlying representation of map still mutable despite frozen wrapper"
-        if value_type == :message
-          internal_iterator do |iterator|
-            value_message_value = Google::Protobuf::FFI.map_value(@map_ptr, iterator)
-            convert_upb_to_ruby(value_message_value, value_type, descriptor, arena).freeze
           end
+          return self
         end
-        self
+        unless Google::Protobuf::FFI.map_frozen? @map_ptr
+          mini_table = (value_type == :message) ? Google::Protobuf::FFI.get_mini_table(@descriptor) : nil
+          Google::Protobuf::FFI.map_freeze(@map_ptr, mini_table)
+        end
+        super
       end
 
       ##
@@ -371,10 +391,14 @@ module Google
         OBJECT_CACHE.try_add(@map_ptr.address, self)
       end
 
-      # @param field [FieldDescriptor] Descriptor of the field where the RepeatedField will be assigned
+      ##
-      # @param values [Hash|Map] Initial value; may be nil or empty
+      # Constructor that uses the type information from the given
+      # FieldDescriptor to configure the new Map instance.
+      # @param field [FieldDescriptor] Type information for the new Map
       # @param arena [Arena] Owning message's arena
-      def self.construct_for_field(field, arena, value: nil, map: nil)
+      # @param value [Hash|Map] Initial value
+      # @param map [::FFI::Pointer] Existing upb_Map
+      def self.construct_for_field(field, arena: nil, value: nil, map: nil)
         raise ArgumentError.new "Expected Hash object as initializer value for map field '#{field.name}' (given #{value.class})." unless value.nil? or value.is_a? Hash
         instance = allocate
         raise ArgumentError.new "Expected field with type :message, instead got #{field.class}" unless field.type == :message

ruby/lib/google/protobuf/ffi/message.rb

@@ -24,6 +24,9 @@ module Google
       attach_function :get_message_which_oneof, :upb_Message_WhichOneofByDef, [:Message, OneofDescriptor], FieldDescriptor
       attach_function :message_discard_unknown, :upb_Message_DiscardUnknown,  [:Message, Descriptor, :int], :bool
       attach_function :message_next,            :upb_Message_Next,            [:Message, Descriptor, :DefPool, :FieldDefPointer, MessageValue.by_ref, :pointer], :bool
+      attach_function :message_freeze,          :upb_Message_Freeze,          [:Message, MiniTable.by_ref], :void
+      attach_function :message_frozen?,         :upb_Message_IsFrozen,        [:Message], :bool
+
       # MessageValue
       attach_function :message_value_equal,     :shared_Msgval_IsEqual,       [MessageValue.by_value, MessageValue.by_value, CType, Descriptor], :bool
       attach_function :message_value_hash,      :shared_Msgval_GetHash,       [MessageValue.by_value, CType, Descriptor, :uint64_t], :uint64_t
@@ -58,18 +61,35 @@ module Google
             instance
           end
 
+          ##
+          # Is this object frozen?
+          # Returns true if either this Ruby wrapper or the underlying
+          # representation are frozen. Freezes the wrapper if the underlying
+          # representation is already frozen but this wrapper isn't.
+          def frozen?
+            unless Google::Protobuf::FFI.message_frozen? @msg
+              raise RuntimeError.new "Ruby frozen Message with mutable representation" if super
+              return false
+            end
+            method(:freeze).super_method.call unless super
+            true
+          end
+
+          ##
+          # Freezes the map object. We have to intercept this so we can freeze the
+          # underlying representation, not just the Ruby wrapper. Returns self.
           def freeze
-            return self if frozen?
+            if method(:frozen?).super_method.call
-            super
+              unless Google::Protobuf::FFI.message_frozen? @msg
-            @arena.pin self
+                raise RuntimeError.new "Underlying representation of message still mutable despite frozen wrapper"
-            self.class.descriptor.each do |field_descriptor|
-              next if field_descriptor.has_presence? && !Google::Protobuf::FFI.get_message_has(@msg, field_descriptor)
-              if field_descriptor.map? or field_descriptor.repeated? or field_descriptor.sub_message?
-                get_field(field_descriptor).freeze
               end
+              return self
             end
-            self
+            unless Google::Protobuf::FFI.message_frozen? @msg
-          end
+              Google::Protobuf::FFI.message_freeze(@msg, Google::Protobuf::FFI.get_mini_table(self.class.descriptor))
+            end
+            super
+         end
 
           def dup
             duplicate = self.class.private_constructor(@arena)
@@ -309,42 +329,136 @@ module Google
 
           include Google::Protobuf::Internal::Convert
 
+          ##
+          # Checks ObjectCache for a sentinel empty frozen Map of the key and
+          # value types matching the field descriptor's MessageDef and returns
+          # the cache entry. If an entry is not found, one is created and added
+          # to the cache keyed by the MessageDef pointer first.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def empty_frozen_map(field_descriptor)
+            sub_message_def = Google::Protobuf::FFI.get_subtype_as_message field_descriptor
+            frozen_map = OBJECT_CACHE.get sub_message_def
+            if frozen_map.nil?
+              frozen_map = Google::Protobuf::Map.send(:construct_for_field, field_descriptor)
+              OBJECT_CACHE.try_add(sub_message_def, frozen_map.freeze)
+            end
+            raise "Empty Frozen Map is not frozen" unless frozen_map.frozen?
+            frozen_map
+          end
+
+          ##
+          # Returns a frozen Map instance for the given field. If the message
+          # already has a value for that field, it is used. If not, a sentinel
+          # (per FieldDescriptor) empty frozen Map is returned instead.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def frozen_map_from_field_descriptor(field_descriptor)
+            message_value = Google::Protobuf::FFI.get_message_value @msg, field_descriptor
+            return empty_frozen_map field_descriptor if message_value[:map_val].null?
+            get_map_field(message_value[:map_val], field_descriptor).freeze
+          end
+
+          ##
+          # Returns a Map instance for the given field. If the message is frozen
+          # the return value is also frozen. If not, a mutable instance is
+          # returned instead.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def map_from_field_descriptor(field_descriptor)
+            return frozen_map_from_field_descriptor field_descriptor if frozen?
+            mutable_message_value = Google::Protobuf::FFI.get_mutable_message @msg, field_descriptor, @arena
+            get_map_field(mutable_message_value[:map], field_descriptor)
+          end
+
+          ##
+          # Checks ObjectCache for a sentinel empty frozen RepeatedField of the
+          # value type matching the field descriptor's MessageDef and returns
+          # the cache entry. If an entry is not found, one is created and added
+          # to the cache keyed by the MessageDef pointer first.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def empty_frozen_repeated_field(field_descriptor)
+            sub_message_def = Google::Protobuf::FFI.get_subtype_as_message field_descriptor
+            frozen_repeated_field = OBJECT_CACHE.get sub_message_def
+            if frozen_repeated_field.nil?
+              frozen_repeated_field = Google::Protobuf::RepeatedField.send(:construct_for_field, field_descriptor)
+              OBJECT_CACHE.try_add(sub_message_def, frozen_repeated_field.freeze)
+            end
+            raise "Empty frozen RepeatedField is not frozen" unless frozen_repeated_field.frozen?
+            frozen_repeated_field
+          end
+
+          ##
+          # Returns a frozen RepeatedField instance for the given field. If the
+          # message already has a value for that field, it is used. If not, a
+          # sentinel (per FieldDescriptor) empty frozen RepeatedField is
+          # returned instead.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def frozen_repeated_field_from_field_descriptor(field_descriptor)
+            message_value = Google::Protobuf::FFI.get_message_value @msg, field_descriptor
+            return empty_frozen_repeated_field field_descriptor if message_value[:array_val].null?
+            get_repeated_field(message_value[:array_val], field_descriptor).freeze
+          end
+
+          ##
+          # Returns a RepeatedField instance for the given field. If the message
+          # is frozen the return value is also frozen. If not, a mutable
+          # instance is returned instead.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def repeated_field_from_field_descriptor(field_descriptor)
+            return frozen_repeated_field_from_field_descriptor field_descriptor if frozen?
+            mutable_message_value = Google::Protobuf::FFI.get_mutable_message @msg, field_descriptor, @arena
+            get_repeated_field(mutable_message_value[:array], field_descriptor)
+          end
+
+          ##
+          # Returns a Message instance for the given field. If the message
+          # is frozen nil is always returned. Otherwise, a mutable instance is
+          # returned instead.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def message_from_field_descriptor(field_descriptor)
+            return nil if frozen?
+            return nil unless Google::Protobuf::FFI.get_message_has @msg, field_descriptor
+            mutable_message = Google::Protobuf::FFI.get_mutable_message @msg, field_descriptor, @arena
+            sub_message = mutable_message[:msg]
+            sub_message_def = Google::Protobuf::FFI.get_subtype_as_message field_descriptor
+            Descriptor.send(:get_message, sub_message, sub_message_def, @arena)
+          end
+
+          ##
+          # Returns a scalar value for the given field. If the message
+          # is frozen the return value is also frozen.
+          # @param field_descriptor [FieldDescriptor] Field to retrieve.
+          def scalar_from_field_descriptor(field_descriptor)
+            c_type = field_descriptor.send(:c_type)
+            message_value = Google::Protobuf::FFI.get_message_value @msg, field_descriptor
+            msg_or_enum_def = c_type == :enum ? Google::Protobuf::FFI.get_subtype_as_enum(field_descriptor) : nil
+            return_value = convert_upb_to_ruby message_value, c_type, msg_or_enum_def
+            frozen? ? return_value.freeze : return_value
+          end
+
+          ##
+          # Dynamically define accessors methods for every field of @descriptor.
+          # Methods with names that conflict with existing methods are skipped.
           def self.setup_accessors!
             @descriptor.each do |field_descriptor|
               field_name = field_descriptor.name
               unless instance_methods(true).include?(field_name.to_sym)
-                #TODO - at a high level, dispatching to either
+                # Dispatching to either index_internal or get_field is logically
-                # index_internal or get_field would be logically correct, but slightly slower.
+                # correct, but slightly slower due to having to perform extra
+                # lookups on each invocation rather than doing it once here.
                 if field_descriptor.map?
                   define_method(field_name) do
-                    mutable_message_value = Google::Protobuf::FFI.get_mutable_message @msg, field_descriptor, @arena
+                    map_from_field_descriptor field_descriptor
-                    get_map_field(mutable_message_value[:map], field_descriptor)
                   end
                 elsif field_descriptor.repeated?
                   define_method(field_name) do
-                    mutable_message_value = Google::Protobuf::FFI.get_mutable_message @msg, field_descriptor, @arena
+                    repeated_field_from_field_descriptor field_descriptor
-                    get_repeated_field(mutable_message_value[:array], field_descriptor)
                   end
                 elsif field_descriptor.sub_message?
                   define_method(field_name) do
-                    return nil unless Google::Protobuf::FFI.get_message_has @msg, field_descriptor
+                    message_from_field_descriptor field_descriptor
-                    mutable_message = Google::Protobuf::FFI.get_mutable_message @msg, field_descriptor, @arena
-                    sub_message = mutable_message[:msg]
-                    sub_message_def = Google::Protobuf::FFI.get_subtype_as_message(field_descriptor)
-                    Descriptor.send(:get_message, sub_message, sub_message_def, @arena)
                   end
                 else
-                  c_type = field_descriptor.send(:c_type)
+                  define_method(field_name) do
-                  if c_type == :enum
+                    scalar_from_field_descriptor field_descriptor
-                    define_method(field_name) do
-                      message_value = Google::Protobuf::FFI.get_message_value @msg, field_descriptor
-                      convert_upb_to_ruby message_value, c_type, Google::Protobuf::FFI.get_subtype_as_enum(field_descriptor)
-                    end
-                  else
-                    define_method(field_name) do
-                      message_value = Google::Protobuf::FFI.get_message_value @msg, field_descriptor
-                      convert_upb_to_ruby message_value, c_type
-                    end
                   end
                 end
                 define_method("#{field_name}=") do |value|
@@ -354,14 +468,16 @@ module Google
                   clear_internal(field_descriptor)
                 end
                 if field_descriptor.type == :enum
-                  define_method("#{field_name}_const") do
+                  if field_descriptor.repeated?
-                    if field_descriptor.repeated?
+                    define_method("#{field_name}_const") do
                       return_value = []
-                      get_field(field_descriptor).send(:each_msg_val) do |msg_val|
+                      repeated_field_from_field_descriptor(field_descriptor).send(:each_msg_val) do |msg_val|
                         return_value << msg_val[:int32_val]
                       end
                       return_value
-                    else
+                    end
+                  else
+                    define_method("#{field_name}_const") do
                       message_value = Google::Protobuf::FFI.get_message_value @msg, field_descriptor
                       message_value[:int32_val]
                     end
@@ -388,12 +504,21 @@ module Google
             end
           end
 
+          ##
+          # Dynamically define accessors methods for every OneOf field of
+          # @descriptor.
           def self.setup_oneof_accessors!
             @oneof_field_names = []
             @descriptor.each_oneof do |oneof_descriptor|
               self.add_oneof_accessors_for! oneof_descriptor
             end
           end
+
+          ##
+          # Dynamically define accessors methods for the given OneOf field.
+          # Methods with names that conflict with existing methods are skipped.
+          # @param oneof_descriptor [OneofDescriptor] Field to create accessors
+          # for.
           def self.add_oneof_accessors_for!(oneof_descriptor)
             field_name = oneof_descriptor.name.to_sym
             @oneof_field_names << field_name
@@ -524,6 +649,10 @@ module Google
             Google::Protobuf::FFI.clear_message_field(@msg, field_def)
           end
 
+          # Accessor for field by name. Does not delegate to methods setup by
+          # self.setup_accessors! in order to avoid conflicts with bad field
+          # names e.g. `dup` or `class` which are perfectly valid for proto
+          # fields.
           def index_internal(name)
             field_descriptor = self.class.descriptor.lookup(name)
             get_field field_descriptor unless field_descriptor.nil?
@@ -572,9 +701,9 @@ module Google
 
                 next if value.nil?
                 if field_descriptor.map?
-                  index_assign_internal(Google::Protobuf::Map.send(:construct_for_field, field_descriptor, @arena, value: value), name: key.to_s)
+                  index_assign_internal(Google::Protobuf::Map.send(:construct_for_field, field_descriptor, arena: @arena, value: value), name: key.to_s)
                 elsif field_descriptor.repeated?
-                  index_assign_internal(RepeatedField.send(:construct_for_field, field_descriptor, @arena, values: value), name: key.to_s)
+                  index_assign_internal(RepeatedField.send(:construct_for_field, field_descriptor, arena: @arena, values: value), name: key.to_s)
                 else
                   index_assign_internal(value, name: key.to_s)
                 end
@@ -587,21 +716,20 @@ module Google
           end
 
           ##
-          # Gets a field of this message identified by the argument definition.
+          # Gets a field of this message identified by FieldDescriptor.
           #
-          # @param field [FieldDescriptor] Descriptor of the field to get
+          # @param field [FieldDescriptor] Field to retrieve.
+          # @param unwrap [Boolean](false) If true, unwraps wrappers.
           def get_field(field, unwrap: false)
             if field.map?
-              mutable_message_value = Google::Protobuf::FFI.get_mutable_message @msg, field, @arena
+              map_from_field_descriptor field
-              get_map_field(mutable_message_value[:map], field)
             elsif field.repeated?
-              mutable_message_value = Google::Protobuf::FFI.get_mutable_message @msg, field, @arena
+              repeated_field_from_field_descriptor field
-              get_repeated_field(mutable_message_value[:array], field)
             elsif field.sub_message?
               return nil unless Google::Protobuf::FFI.get_message_has @msg, field
-              sub_message_def = Google::Protobuf::FFI.get_subtype_as_message(field)
               if unwrap
                 if field.has?(self)
+                  sub_message_def = Google::Protobuf::FFI.get_subtype_as_message field
                   wrapper_message_value = Google::Protobuf::FFI.get_message_value @msg, field
                   fields = Google::Protobuf::FFI.field_count(sub_message_def)
                   raise "Sub message has #{fields} fields! Expected exactly 1." unless fields == 1
@@ -612,42 +740,36 @@ module Google
                   nil
                 end
               else
-                mutable_message = Google::Protobuf::FFI.get_mutable_message @msg, field, @arena
+                message_from_field_descriptor field
-                sub_message = mutable_message[:msg]
-                Descriptor.send(:get_message, sub_message, sub_message_def, @arena)
               end
             else
-              c_type = field.send(:c_type)
+              scalar_from_field_descriptor field
-              message_value = Google::Protobuf::FFI.get_message_value @msg, field
-              if c_type == :enum
-                convert_upb_to_ruby message_value, c_type, Google::Protobuf::FFI.get_subtype_as_enum(field)
-              else
-                convert_upb_to_ruby message_value, c_type
-              end
             end
           end
 
           ##
-          # @param array [::FFI::Pointer] Pointer to the Array
+          # Gets a RepeatedField from the ObjectCache or creates a new one.
+          # @param array [::FFI::Pointer] Pointer to the upb_Array
           # @param field [Google::Protobuf::FieldDescriptor] Type of the repeated field
           def get_repeated_field(array, field)
             return nil if array.nil? or array.null?
             repeated_field = OBJECT_CACHE.get(array.address)
             if repeated_field.nil?
-              repeated_field = RepeatedField.send(:construct_for_field, field, @arena, array: array)
+              repeated_field = RepeatedField.send(:construct_for_field, field, arena: @arena, array: array)
               repeated_field.freeze if frozen?
             end
             repeated_field
           end
 
           ##
-          # @param map [::FFI::Pointer] Pointer to the Map
+          # Gets a Map from the ObjectCache or creates a new one.
+          # @param map [::FFI::Pointer] Pointer to the upb_Map
           # @param field [Google::Protobuf::FieldDescriptor] Type of the map field
           def get_map_field(map, field)
             return nil if map.nil? or map.null?
             map_field = OBJECT_CACHE.get(map.address)
             if map_field.nil?
-              map_field = Google::Protobuf::Map.send(:construct_for_field, field, @arena, map: map)
+              map_field = Google::Protobuf::Map.send(:construct_for_field, field, arena: @arena, map: map)
               map_field.freeze if frozen?
             end
             map_field

ruby/lib/google/protobuf/ffi/repeated_field.rb

@@ -24,12 +24,14 @@ module Google
   module Protobuf
     class FFI
       # Array
-      attach_function :append_array, :upb_Array_Append,        [:Array, MessageValue.by_value, Internal::Arena], :bool
+      attach_function :append_array,  :upb_Array_Append,   [:Array, MessageValue.by_value, Internal::Arena], :bool
-      attach_function :get_msgval_at,:upb_Array_Get,           [:Array, :size_t], MessageValue.by_value
+      attach_function :get_msgval_at, :upb_Array_Get,      [:Array, :size_t], MessageValue.by_value
-      attach_function :create_array, :upb_Array_New,           [Internal::Arena, CType], :Array
+      attach_function :create_array,  :upb_Array_New,      [Internal::Arena, CType], :Array
-      attach_function :array_resize, :upb_Array_Resize,        [:Array, :size_t, Internal::Arena], :bool
+      attach_function :array_resize,  :upb_Array_Resize,   [:Array, :size_t, Internal::Arena], :bool
-      attach_function :array_set,    :upb_Array_Set,           [:Array, :size_t, MessageValue.by_value], :void
+      attach_function :array_set,     :upb_Array_Set,      [:Array, :size_t, MessageValue.by_value], :void
-      attach_function :array_size,   :upb_Array_Size,          [:Array], :size_t
+      attach_function :array_size,    :upb_Array_Size,     [:Array], :size_t
+      attach_function :array_freeze,  :upb_Array_Freeze,   [:Array, MiniTable.by_ref], :void
+      attach_function :array_frozen?, :upb_Array_IsFrozen, [:Array], :bool
     end
 
     class RepeatedField
@@ -174,16 +176,36 @@ module Google
       end
       alias size :length
 
+      ##
+      # Is this object frozen?
+      # Returns true if either this Ruby wrapper or the underlying
+      # representation are frozen. Freezes the wrapper if the underlying
+      # representation is already frozen but this wrapper isn't.
+      def frozen?
+        unless Google::Protobuf::FFI.array_frozen? array
+          raise RuntimeError.new "Ruby frozen RepeatedField with mutable representation" if super
+          return false
+        end
+        method(:freeze).super_method.call unless super
+        true
+      end
+
+      ##
+      # Freezes the RepeatedField object. We have to intercept this so we can
+      # freeze the underlying representation, not just the Ruby wrapper. Returns
+      # self.
       def freeze
-        return self if frozen?
+        if method(:frozen?).super_method.call
-        super
+          unless Google::Protobuf::FFI.array_frozen? array
-        @arena.pin self
+            raise RuntimeError.new "Underlying representation of repeated field still mutable despite frozen wrapper"
-        if type == :message
-          each do |element|
-            element.freeze
           end
+          return self
         end
-        self
+        unless Google::Protobuf::FFI.array_frozen? array
+          mini_table = (type == :message) ? Google::Protobuf::FFI.get_mini_table(@descriptor) : nil
+          Google::Protobuf::FFI.array_freeze(array, mini_table)
+        end
+        super
       end
 
       def dup
@@ -348,10 +370,14 @@ module Google
         OBJECT_CACHE.try_add(@array.address, self)
       end
 
-      # @param field [FieldDescriptor] Descriptor of the field where the RepeatedField will be assigned
+      ##
-      # @param values [Enumerable] Initial values; may be nil or empty
+      # Constructor that uses the type information from the given
+      # FieldDescriptor to configure the new RepeatedField instance.
+      # @param field [FieldDescriptor] Type information for the new RepeatedField
       # @param arena [Arena] Owning message's arena
-      def self.construct_for_field(field, arena, values: nil, array: nil)
+      # @param values [Enumerable] Initial values
+      # @param array [::FFI::Pointer] Existing upb_Array
+      def self.construct_for_field(field, arena: nil, values: nil, array: nil)
         instance = allocate
         options = {initial_values: values, name: field.name, arena: arena, array: array}
         if [:enum, :message].include? field.type