// Protocol Buffers - Google's data interchange format
// Copyright 2008 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.

// Author: kenton@google.com (Kenton Varda)
//  Based on original Protocol Buffers design by
//  Sanjay Ghemawat, Jeff Dean, and others.

#include <memory>
#include <string>
#include <tuple>

#include "absl/container/flat_hash_map.h"
#include "absl/log/absl_check.h"
#include "absl/memory/memory.h"
#include "absl/strings/str_cat.h"
#include "google/protobuf/compiler/cpp/field.h"
#include "google/protobuf/compiler/cpp/field_generators/generators.h"
#include "google/protobuf/compiler/cpp/helpers.h"
#include "google/protobuf/io/printer.h"

namespace google {
namespace protobuf {
namespace compiler {
namespace cpp {
namespace {
std::string ReinterpretCast(absl::string_view type,
                            absl::string_view expression,
                            bool implicit_weak_field) {
  if (implicit_weak_field) {
    return absl::StrCat("reinterpret_cast< ", type, " >(", expression, ")");
  } else {
    return std::string(expression);
  }
}

void SetMessageVariables(
    const FieldDescriptor* descriptor, const Options& options,
    bool implicit_weak,
    absl::flat_hash_map<absl::string_view, std::string>* variables) {
  bool split = ShouldSplit(descriptor, options);
  std::string field_name = FieldMemberName(descriptor, split);

  (*variables)["type"] = FieldMessageTypeName(descriptor, options);
  variables->insert(
      {"casted_member", ReinterpretCast(absl::StrCat((*variables)["type"], "*"),
                                        field_name, implicit_weak)});
  variables->insert(
      {"casted_member_const",
       ReinterpretCast(absl::StrCat("const ", (*variables)["type"], "&"),
                       absl::StrCat("*", field_name), implicit_weak)});
  (*variables)["type_default_instance"] =
      QualifiedDefaultInstanceName(descriptor->message_type(), options);
  (*variables)["type_default_instance_ptr"] = ReinterpretCast(
      "const ::PROTOBUF_NAMESPACE_ID::MessageLite*",
      QualifiedDefaultInstancePtr(descriptor->message_type(), options),
      implicit_weak);
  variables->insert(
      {"type_reference_function",
       implicit_weak
           ? absl::StrCat("  ::", ProtobufNamespace(options),
                          "::internal::StrongReference(reinterpret_cast<const ",
                          (*variables)["type"], "&>(\n",
                          (*variables)["type_default_instance"], "));\n")
           : ""});
  // NOTE: Escaped here to unblock proto1->proto2 migration.
  // TODO(liujisi): Extend this to apply for other conflicting methods.
  (*variables)["release_name"] =
      SafeFunctionName(descriptor->containing_type(), descriptor, "release_");
  (*variables)["full_name"] = descriptor->full_name();
}

class MessageFieldGenerator : public FieldGeneratorBase {
 public:
  MessageFieldGenerator(const FieldDescriptor* descriptor,
                        const Options& options,
                        MessageSCCAnalyzer* scc_analyzer);
  ~MessageFieldGenerator() override = default;

  void GeneratePrivateMembers(io::Printer* printer) const override;
  void GenerateAccessorDeclarations(io::Printer* printer) const override;
  void GenerateInlineAccessorDefinitions(io::Printer* printer) const override;
  void GenerateNonInlineAccessorDefinitions(
      io::Printer* printer) const override;
  void GenerateInternalAccessorDeclarations(
      io::Printer* printer) const override;
  void GenerateInternalAccessorDefinitions(io::Printer* printer) const override;
  void GenerateClearingCode(io::Printer* printer) const override;
  void GenerateMessageClearingCode(io::Printer* printer) const override;
  void GenerateMergingCode(io::Printer* printer) const override;
  void GenerateSwappingCode(io::Printer* printer) const override;
  void GenerateDestructorCode(io::Printer* printer) const override;
  void GenerateConstructorCode(io::Printer* printer) const override {}
  void GenerateCopyConstructorCode(io::Printer* printer) const override;
  void GenerateSerializeWithCachedSizesToArray(
      io::Printer* printer) const override;
  void GenerateByteSize(io::Printer* printer) const override;
  void GenerateIsInitialized(io::Printer* printer) const override;
  void GenerateConstexprAggregateInitializer(
      io::Printer* printer) const override;
  void GenerateAggregateInitializer(io::Printer* printer) const override;
  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;

 protected:
  bool implicit_weak_field_;
  bool has_required_fields_;
};

class MessageOneofFieldGenerator : public MessageFieldGenerator {
 public:
  MessageOneofFieldGenerator(const FieldDescriptor* descriptor,
                             const Options& options,
                             MessageSCCAnalyzer* scc_analyzer);
  ~MessageOneofFieldGenerator() override = default;

  void GenerateInlineAccessorDefinitions(io::Printer* printer) const override;
  void GenerateNonInlineAccessorDefinitions(
      io::Printer* printer) const override;
  void GenerateClearingCode(io::Printer* printer) const override;
  void GenerateMessageClearingCode(io::Printer* printer) const override;
  void GenerateSwappingCode(io::Printer* printer) const override;
  void GenerateDestructorCode(io::Printer* printer) const override;
  void GenerateConstructorCode(io::Printer* printer) const override;
  void GenerateIsInitialized(io::Printer* printer) const override;
};

class RepeatedMessageFieldGenerator : public FieldGeneratorBase {
 public:
  RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor,
                                const Options& options,
                                MessageSCCAnalyzer* scc_analyzer);
  ~RepeatedMessageFieldGenerator() override = default;

  void GeneratePrivateMembers(io::Printer* printer) const override;
  void GenerateAccessorDeclarations(io::Printer* printer) const override;
  void GenerateInlineAccessorDefinitions(io::Printer* printer) const override;
  void GenerateClearingCode(io::Printer* printer) const override;
  void GenerateMergingCode(io::Printer* printer) const override;
  void GenerateSwappingCode(io::Printer* printer) const override;
  void GenerateConstructorCode(io::Printer* printer) const override;
  void GenerateCopyConstructorCode(io::Printer* printer) const override {}
  void GenerateDestructorCode(io::Printer* printer) const override;
  void GenerateSerializeWithCachedSizesToArray(
      io::Printer* printer) const override;
  void GenerateByteSize(io::Printer* printer) const override;
  void GenerateIsInitialized(io::Printer* printer) const override;

 private:
  bool implicit_weak_field_;
  bool has_required_fields_;
};

// ===================================================================

MessageFieldGenerator::MessageFieldGenerator(const FieldDescriptor* descriptor,
                                             const Options& options,
                                             MessageSCCAnalyzer* scc_analyzer)
    : FieldGeneratorBase(descriptor, options),
      implicit_weak_field_(
          IsImplicitWeakField(descriptor, options, scc_analyzer)),
      has_required_fields_(
          scc_analyzer->HasRequiredFields(descriptor->message_type())) {
  SetMessageVariables(descriptor, options, implicit_weak_field_, &variables_);
}

void MessageFieldGenerator::GeneratePrivateMembers(io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format("::$proto_ns$::MessageLite* $name$_;\n");
  } else {
    format("$type$* $name$_;\n");
  }
}

void MessageFieldGenerator::GenerateAccessorDeclarations(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "$deprecated_attr$const $type$& ${1$$name$$}$() const;\n"
      "PROTOBUF_NODISCARD $deprecated_attr$$type$* "
      "${1$$release_name$$}$();\n",
      descriptor_);
  format("$deprecated_attr$$type$* ${1$mutable_$name$$}$();\n",
         std::make_tuple(descriptor_, GeneratedCodeInfo::Annotation::ALIAS));
  format(
      "$deprecated_attr$void ${1$set_allocated_$name$$}$"
      "($type$* $name$);\n"
      "private:\n"
      "const $type$& ${1$_internal_$name$$}$() const;\n"
      "$type$* ${1$_internal_mutable_$name$$}$();\n"
      "public:\n",
      descriptor_);
  format(
      "$deprecated_attr$void "
      "${1$unsafe_arena_set_allocated_$name$$}$(\n"
      "    $type$* $name$);\n"
      "$deprecated_attr$$type$* ${1$unsafe_arena_release_$name$$}$();\n",
      descriptor_);
}

void MessageFieldGenerator::GenerateNonInlineAccessorDefinitions(
    io::Printer* printer) const {}

void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "inline const $type$& $classname$::_internal_$name$() const {\n"
      "$type_reference_function$"
      "  const $type$* p = $casted_member$;\n"
      "  return p != nullptr ? *p : reinterpret_cast<const $type$&>(\n"
      "      $type_default_instance$);\n"
      "}\n"
      "inline const $type$& $classname$::$name$() const {\n"
      "$annotate_get$"
      "  // @@protoc_insertion_point(field_get:$full_name$)\n"
      "  return _internal_$name$();\n"
      "}\n");

  format(
      "inline void $classname$::unsafe_arena_set_allocated_$name$(\n"
      "    $type$* $name$) {\n"
      "$maybe_prepare_split_message$"
      // If we're not on an arena, free whatever we were holding before.
      // (If we are on arena, we can just forget the earlier pointer.)
      "  if (GetArenaForAllocation() == nullptr) {\n"
      "    delete reinterpret_cast<::$proto_ns$::MessageLite*>($field$);\n"
      "  }\n");
  if (implicit_weak_field_) {
    format(
        "  $field$ = reinterpret_cast<::$proto_ns$::MessageLite*>($name$);\n");
  } else {
    format("  $field$ = $name$;\n");
  }
  if (internal::cpp::HasHasbit(descriptor_)) {
    format(
        "  if ($name$) {\n"
        "    $set_hasbit$\n"
        "  } else {\n"
        "    $clear_hasbit$\n"
        "  }\n");
  }
  format(
      "$annotate_set$"
      "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated"
      ":$full_name$)\n"
      "}\n");
  format(
      "inline $type$* $classname$::$release_name$() {\n"
      "$type_reference_function$"
      "$annotate_release$"
      "$maybe_prepare_split_message$"
      "  $clear_hasbit$\n"
      "  $type$* temp = $casted_member$;\n"
      "  $field$ = nullptr;\n"
      "#ifdef PROTOBUF_FORCE_COPY_IN_RELEASE\n"
      "  auto* old =  reinterpret_cast<::$proto_ns$::MessageLite*>(temp);\n"
      "  temp = ::$proto_ns$::internal::DuplicateIfNonNull(temp);\n"
      "  if (GetArenaForAllocation() == nullptr) { delete old; }\n"
      "#else  // PROTOBUF_FORCE_COPY_IN_RELEASE\n"
      "  if (GetArenaForAllocation() != nullptr) {\n"
      "    temp = ::$proto_ns$::internal::DuplicateIfNonNull(temp);\n"
      "  }\n"
      "#endif  // !PROTOBUF_FORCE_COPY_IN_RELEASE\n"
      "  return temp;\n"
      "}\n"
      "inline $type$* $classname$::unsafe_arena_release_$name$() {\n"
      "$annotate_release$"
      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
      "$type_reference_function$"
      "$maybe_prepare_split_message$"
      "  $clear_hasbit$\n"
      "  $type$* temp = $casted_member$;\n"
      "  $field$ = nullptr;\n"
      "  return temp;\n"
      "}\n");

  format(
      "inline $type$* $classname$::_internal_mutable_$name$() {\n"
      "$type_reference_function$"
      "  $set_hasbit$\n"
      "  if ($field$ == nullptr) {\n"
      "    auto* p = CreateMaybeMessage<$type$>(GetArenaForAllocation());\n");
  if (implicit_weak_field_) {
    format("    $field$ = reinterpret_cast<::$proto_ns$::MessageLite*>(p);\n");
  } else {
    format("    $field$ = p;\n");
  }
  format(
      "  }\n"
      "  return $casted_member$;\n"
      "}\n"
      "inline $type$* $classname$::mutable_$name$() {\n"
      // TODO(b/122856539): add tests to make sure all write accessors are able
      // to prepare split message allocation.
      "$maybe_prepare_split_message$"
      "  $type$* _msg = _internal_mutable_$name$();\n"
      "$annotate_mutable$"
      "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
      "  return _msg;\n"
      "}\n");

  // We handle the most common case inline, and delegate less common cases to
  // the slow fallback function.
  format(
      "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
      "  ::$proto_ns$::Arena* message_arena = GetArenaForAllocation();\n");
  format(
      "$maybe_prepare_split_message$"
      "  if (message_arena == nullptr) {\n");
  if (IsCrossFileMessage(descriptor_)) {
    format(
        "    delete reinterpret_cast< ::$proto_ns$::MessageLite*>($field$);\n");
  } else {
    format("    delete $field$;\n");
  }
  format(
      "  }\n"
      "  if ($name$) {\n");
  if (IsCrossFileMessage(descriptor_)) {
    // We have to read the arena through the virtual method, because the type
    // isn't defined in this file.
    format(
        "    ::$proto_ns$::Arena* submessage_arena =\n"
        "        ::$proto_ns$::Arena::InternalGetOwningArena(\n"
        "                reinterpret_cast<::$proto_ns$::MessageLite*>("
        "$name$));\n");
  } else {
    format(
        "    ::$proto_ns$::Arena* submessage_arena =\n"
        "        ::$proto_ns$::Arena::InternalGetOwningArena("
        "$name$);\n");
  }
  format(
      "    if (message_arena != submessage_arena) {\n"
      "      $name$ = ::$proto_ns$::internal::GetOwnedMessage(\n"
      "          message_arena, $name$, submessage_arena);\n"
      "    }\n"
      "    $set_hasbit$\n"
      "  } else {\n"
      "    $clear_hasbit$\n"
      "  }\n");
  if (implicit_weak_field_) {
    format("  $field$ = reinterpret_cast<MessageLite*>($name$);\n");
  } else {
    format("  $field$ = $name$;\n");
  }
  format(
      "$annotate_set$"
      "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
      "}\n");
}

void MessageFieldGenerator::GenerateInternalAccessorDeclarations(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format(
        "static const ::$proto_ns$::MessageLite& $name$("
        "const $classname$* msg);\n"
        "static ::$proto_ns$::MessageLite* mutable_$name$("
        "$classname$* msg);\n");
  } else {
    format("static const $type$& $name$(const $classname$* msg);\n");
  }
}

void MessageFieldGenerator::GenerateInternalAccessorDefinitions(
    io::Printer* printer) const {
  // In theory, these accessors could be inline in _Internal. However, in
  // practice, the linker is then not able to throw them out making implicit
  // weak dependencies not work at all.
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    // These private accessors are used by MergeFrom and
    // MergePartialFromCodedStream, and their purpose is to provide access to
    // the field without creating a strong dependency on the message type.
    format(
        "const ::$proto_ns$::MessageLite& $classname$::_Internal::$name$(\n"
        "    const $classname$* msg) {\n"
        "  if (msg->$field$ != nullptr) {\n"
        "    return *msg->$field$;\n"
        "  } else {\n"
        "    return *$type_default_instance_ptr$;\n"
        "  }\n"
        "}\n");
    format(
        "::$proto_ns$::MessageLite*\n"
        "$classname$::_Internal::mutable_$name$($classname$* msg) {\n");
    if (internal::cpp::HasHasbit(descriptor_)) {
      format("  msg->$set_hasbit$\n");
    }
    if (descriptor_->real_containing_oneof() == nullptr) {
      format("  if (msg->$field$ == nullptr) {\n");
    } else {
      format(
          "  if (msg->$not_has_field$) {\n"
          "    msg->clear_$oneof_name$();\n"
          "    msg->set_has_$name$();\n");
    }
    format(
        "    msg->$field$ = $type_default_instance_ptr$->New(\n"
        "        msg->GetArenaForAllocation());\n"
        "  }\n"
        "  return msg->$field$;\n"
        "}\n");
  } else {
    // This inline accessor directly returns member field and is used in
    // Serialize such that AFDO profile correctly captures access information to
    // message fields under serialize.
    format(
        "const $type$&\n"
        "$classname$::_Internal::$name$(const $classname$* msg) {\n"
        "  return *msg->$field$;\n"
        "}\n");
  }
}

void MessageFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (!internal::cpp::HasHasbit(descriptor_)) {
    // If we don't have has-bits, message presence is indicated only by ptr !=
    // nullptr. Thus on clear, we need to delete the object.
    format(
        "if (GetArenaForAllocation() == nullptr && $field$ != nullptr) {\n"
        "  delete $field$;\n"
        "}\n"
        "$field$ = nullptr;\n");
  } else {
    format("if ($field$ != nullptr) $field$->Clear();\n");
  }
}

void MessageFieldGenerator::GenerateMessageClearingCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (!internal::cpp::HasHasbit(descriptor_)) {
    // If we don't have has-bits, message presence is indicated only by ptr !=
    // nullptr. Thus on clear, we need to delete the object.
    format(
        "if (GetArenaForAllocation() == nullptr && $field$ != nullptr) {\n"
        "  delete $field$;\n"
        "}\n"
        "$field$ = nullptr;\n");
  } else {
    format(
        "$DCHK$($field$ != nullptr);\n"
        "$field$->Clear();\n");
  }
}

void MessageFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format(
        "_Internal::mutable_$name$(_this)->CheckTypeAndMergeFrom(\n"
        "    _Internal::$name$(&from));\n");
  } else {
    format(
        "_this->_internal_mutable_$name$()->$type$::MergeFrom(\n"
        "    from._internal_$name$());\n");
  }
}

void MessageFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("swap($field$, other->$field$);\n");
}

void MessageFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (options_.opensource_runtime) {
    // TODO(gerbens) Remove this when we don't need to destruct default
    // instances.  In google3 a default instance will never get deleted so we
    // don't need to worry about that but in opensource protobuf default
    // instances are deleted in shutdown process and we need to take special
    // care when handling them.
    format("if (this != internal_default_instance()) ");
  }
  if (ShouldSplit(descriptor_, options_)) {
    format("delete $cached_split_ptr$->$name$_;\n");
    return;
  }
  format("delete $field$;\n");
}

using internal::cpp::HasHasbit;

void MessageFieldGenerator::GenerateCopyConstructorCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (HasHasbit(descriptor_)) {
    format(
        "if ((from.$has_hasbit$) != 0) {\n"
        "  _this->$field$ = new $type$(*from.$field$);\n"
        "}\n");
  } else {
    format(
        "if (from._internal_has_$name$()) {\n"
        "  _this->$field$ = new $type$(*from.$field$);\n"
        "}\n");
  }
}

void MessageFieldGenerator::GenerateSerializeWithCachedSizesToArray(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (descriptor_->type() == FieldDescriptor::TYPE_MESSAGE) {
    format(
        "target = ::$proto_ns$::internal::WireFormatLite::\n"
        "  InternalWrite$declared_type$($number$, _Internal::$name$(this),\n"
        "    _Internal::$name$(this).GetCachedSize(), target, stream);\n");
  } else {
    format(
        "target = stream->EnsureSpace(target);\n"
        "target = ::$proto_ns$::internal::WireFormatLite::\n"
        "  InternalWrite$declared_type$(\n"
        "    $number$, _Internal::$name$(this), target, stream);\n");
  }
}

void MessageFieldGenerator::GenerateByteSize(io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "total_size += $tag_size$ +\n"
      "  ::$proto_ns$::internal::WireFormatLite::$declared_type$Size(\n"
      "    *$field$);\n");
}

void MessageFieldGenerator::GenerateIsInitialized(io::Printer* printer) const {
  if (!has_required_fields_) return;

  Formatter format(printer, variables_);
  if (HasHasbit(descriptor_)) {
    format(
        "if (($has_hasbit$) != 0) {\n"
        "  if (!$field$->IsInitialized()) return false;\n"
        "}\n");
  } else {
    format(
        "if (_internal_has_$name$()) {\n"
        "  if (!$field$->IsInitialized()) return false;\n"
        "}\n");
  }
}

void MessageFieldGenerator::GenerateConstexprAggregateInitializer(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("/*decltype($field$)*/nullptr");
}

void MessageFieldGenerator::GenerateCopyAggregateInitializer(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("decltype($field$){nullptr}");
}

void MessageFieldGenerator::GenerateAggregateInitializer(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (ShouldSplit(descriptor_, options_)) {
    format("decltype(Impl_::Split::$name$_){nullptr}");
    return;
  }
  format("decltype($field$){nullptr}");
}

// ===================================================================

MessageOneofFieldGenerator::MessageOneofFieldGenerator(
    const FieldDescriptor* descriptor, const Options& options,
    MessageSCCAnalyzer* scc_analyzer)
    : MessageFieldGenerator(descriptor, options, scc_analyzer) {
}

void MessageOneofFieldGenerator::GenerateNonInlineAccessorDefinitions(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "void $classname$::set_allocated_$name$($type$* $name$) {\n"
      "  ::$proto_ns$::Arena* message_arena = GetArenaForAllocation();\n"
      "  clear_$oneof_name$();\n"
      "  if ($name$) {\n");
  if (descriptor_->file() != descriptor_->message_type()->file()) {
    // We have to read the arena through the virtual method, because the type
    // isn't defined in this file.
    format(
        "    ::$proto_ns$::Arena* submessage_arena =\n"
        "        ::$proto_ns$::Arena::InternalGetOwningArena(\n"
        "                reinterpret_cast<::$proto_ns$::MessageLite*>("
        "$name$));\n");
  } else {
    format(
        "    ::$proto_ns$::Arena* submessage_arena =\n"
        "      ::$proto_ns$::Arena::InternalGetOwningArena($name$);\n");
  }
  format(
      "    if (message_arena != submessage_arena) {\n"
      "      $name$ = ::$proto_ns$::internal::GetOwnedMessage(\n"
      "          message_arena, $name$, submessage_arena);\n"
      "    }\n"
      "    set_has_$name$();\n"
      "    $field$ = $name$;\n"
      "  }\n"
      "$annotate_set$"
      "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
      "}\n");
}

void MessageOneofFieldGenerator::GenerateInlineAccessorDefinitions(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "inline $type$* $classname$::$release_name$() {\n"
      "$annotate_release$"
      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
      "$type_reference_function$"
      "  if ($has_field$) {\n"
      "    clear_has_$oneof_name$();\n"
      "    $type$* temp = $casted_member$;\n"
      "    if (GetArenaForAllocation() != nullptr) {\n"
      "      temp = ::$proto_ns$::internal::DuplicateIfNonNull(temp);\n"
      "    }\n"
      "    $field$ = nullptr;\n"
      "    return temp;\n"
      "  } else {\n"
      "    return nullptr;\n"
      "  }\n"
      "}\n");

  format(
      "inline const $type$& $classname$::_internal_$name$() const {\n"
      "$type_reference_function$"
      "  return $has_field$\n"
      "      ? $casted_member_const$\n"
      "      : reinterpret_cast< $type$&>($type_default_instance$);\n"
      "}\n"
      "inline const $type$& $classname$::$name$() const {\n"
      "$annotate_get$"
      "  // @@protoc_insertion_point(field_get:$full_name$)\n"
      "  return _internal_$name$();\n"
      "}\n"
      "inline $type$* $classname$::unsafe_arena_release_$name$() {\n"
      "$annotate_release$"
      "  // @@protoc_insertion_point(field_unsafe_arena_release"
      ":$full_name$)\n"
      "$type_reference_function$"
      "  if ($has_field$) {\n"
      "    clear_has_$oneof_name$();\n"
      "    $type$* temp = $casted_member$;\n"
      "    $field$ = nullptr;\n"
      "    return temp;\n"
      "  } else {\n"
      "    return nullptr;\n"
      "  }\n"
      "}\n"
      "inline void $classname$::unsafe_arena_set_allocated_$name$"
      "($type$* $name$) {\n"
      // We rely on the oneof clear method to free the earlier contents of
      // this oneof. We can directly use the pointer we're given to set the
      // new value.
      "  clear_$oneof_name$();\n"
      "  if ($name$) {\n"
      "    set_has_$name$();\n");
  if (implicit_weak_field_) {
    format(
        "    $field$ = "
        "reinterpret_cast<::$proto_ns$::MessageLite*>($name$);\n");
  } else {
    format("    $field$ = $name$;\n");
  }
  format(
      "  }\n"
      "$annotate_set$"
      "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:"
      "$full_name$)\n"
      "}\n"
      "inline $type$* $classname$::_internal_mutable_$name$() {\n"
      "$type_reference_function$"
      "  if ($not_has_field$) {\n"
      "    clear_$oneof_name$();\n"
      "    set_has_$name$();\n");
  if (implicit_weak_field_) {
    format(
        "    $field$ = "
        "reinterpret_cast<::$proto_ns$::MessageLite*>(CreateMaybeMessage< "
        "$type$ >(GetArenaForAllocation()));\n");
  } else {
    format(
        "    $field$ = CreateMaybeMessage< $type$ "
        ">(GetArenaForAllocation());\n");
  }
  format(
      "  }\n"
      "  return $casted_member$;\n"
      "}\n"
      "inline $type$* $classname$::mutable_$name$() {\n"
      "  $type$* _msg = _internal_mutable_$name$();\n"
      "$annotate_mutable$"
      "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
      "  return _msg;\n"
      "}\n");
}

void MessageOneofFieldGenerator::GenerateClearingCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "if (GetArenaForAllocation() == nullptr) {\n"
      "  delete $field$;\n"
      "}\n");
}

void MessageOneofFieldGenerator::GenerateMessageClearingCode(
    io::Printer* printer) const {
  GenerateClearingCode(printer);
}

void MessageOneofFieldGenerator::GenerateSwappingCode(
    io::Printer* printer) const {
  // Don't print any swapping code. Swapping the union will swap this field.
}

void MessageOneofFieldGenerator::GenerateDestructorCode(
    io::Printer* printer) const {
  // We inherit from MessageFieldGenerator, so we need to override the default
  // behavior.
}

void MessageOneofFieldGenerator::GenerateConstructorCode(
    io::Printer* printer) const {
  // Don't print any constructor code. The field is in a union. We allocate
  // space only when this field is used.
}

void MessageOneofFieldGenerator::GenerateIsInitialized(
    io::Printer* printer) const {
  if (!has_required_fields_) return;

  Formatter format(printer, variables_);
  format(
      "if ($has_field$) {\n"
      "  if (!$field$->IsInitialized()) return false;\n"
      "}\n");
}

// ===================================================================

RepeatedMessageFieldGenerator::RepeatedMessageFieldGenerator(
    const FieldDescriptor* descriptor, const Options& options,
    MessageSCCAnalyzer* scc_analyzer)
    : FieldGeneratorBase(descriptor, options),
      implicit_weak_field_(
          IsImplicitWeakField(descriptor, options, scc_analyzer)),
      has_required_fields_(
          scc_analyzer->HasRequiredFields(descriptor->message_type())) {
  SetMessageVariables(descriptor, options, implicit_weak_field_, &variables_);
}

void RepeatedMessageFieldGenerator::GeneratePrivateMembers(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format("::$proto_ns$::WeakRepeatedPtrField< $type$ > $name$_;\n");
  } else {
    format("::$proto_ns$::RepeatedPtrField< $type$ > $name$_;\n");
  }
}

void RepeatedMessageFieldGenerator::GenerateAccessorDeclarations(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("$deprecated_attr$$type$* ${1$mutable_$name$$}$(int index);\n",
         std::make_tuple(descriptor_, GeneratedCodeInfo::Annotation::ALIAS));
  format(
      "$deprecated_attr$::$proto_ns$::RepeatedPtrField< $type$ >*\n"
      "    ${1$mutable_$name$$}$();\n",
      std::make_tuple(descriptor_, GeneratedCodeInfo::Annotation::ALIAS));
  format(
      "private:\n"
      "const $type$& ${1$_internal_$name$$}$(int index) const;\n"
      "$type$* ${1$_internal_add_$name$$}$();\n"
      "public:\n",
      descriptor_);
  format(
      "$deprecated_attr$const $type$& ${1$$name$$}$(int index) const;\n"
      "$deprecated_attr$$type$* ${1$add_$name$$}$();\n"
      "$deprecated_attr$const ::$proto_ns$::RepeatedPtrField< $type$ >&\n"
      "    ${1$$name$$}$() const;\n",
      descriptor_);
}

void RepeatedMessageFieldGenerator::GenerateInlineAccessorDefinitions(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format.Set("weak", implicit_weak_field_ ? ".weak" : "");

  format(
      "inline $type$* $classname$::mutable_$name$(int index) {\n"
      "$annotate_mutable$"
      // TODO(dlj): move insertion points
      "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
      "$type_reference_function$"
      "  return $field$$weak$.Mutable(index);\n"
      "}\n"
      "inline ::$proto_ns$::RepeatedPtrField< $type$ >*\n"
      "$classname$::mutable_$name$() {\n"
      "$annotate_mutable_list$"
      "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
      "$type_reference_function$"
      "  return &$field$$weak$;\n"
      "}\n");

  if (options_.safe_boundary_check) {
    format(
        "inline const $type$& $classname$::_internal_$name$(int index) const "
        "{\n"
        "  return $field$$weak$.InternalCheckedGet(index,\n"
        "      reinterpret_cast<const $type$&>($type_default_instance$));\n"
        "}\n");
  } else {
    format(
        "inline const $type$& $classname$::_internal_$name$(int index) const "
        "{\n"
        "$type_reference_function$"
        "  return $field$$weak$.Get(index);\n"
        "}\n");
  }

  format(
      "inline const $type$& $classname$::$name$(int index) const {\n"
      "$annotate_get$"
      "  // @@protoc_insertion_point(field_get:$full_name$)\n"
      "  return _internal_$name$(index);\n"
      "}\n"
      "inline $type$* $classname$::_internal_add_$name$() {\n"
      "  return $field$$weak$.Add();\n"
      "}\n"
      "inline $type$* $classname$::add_$name$() {\n"
      "  $type$* _add = _internal_add_$name$();\n"
      "$annotate_add_mutable$"
      "  // @@protoc_insertion_point(field_add:$full_name$)\n"
      "  return _add;\n"
      "}\n");

  format(
      "inline const ::$proto_ns$::RepeatedPtrField< $type$ >&\n"
      "$classname$::$name$() const {\n"
      "$annotate_list$"
      "  // @@protoc_insertion_point(field_list:$full_name$)\n"
      "$type_reference_function$"
      "  return $field$$weak$;\n"
      "}\n");
}

void RepeatedMessageFieldGenerator::GenerateClearingCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("$field$.Clear();\n");
}

void RepeatedMessageFieldGenerator::GenerateMergingCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("_this->$field$.MergeFrom(from.$field$);\n");
}

void RepeatedMessageFieldGenerator::GenerateSwappingCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format("$field$.InternalSwap(&other->$field$);\n");
}

void RepeatedMessageFieldGenerator::GenerateConstructorCode(
    io::Printer* printer) const {
  // Not needed for repeated fields.
}

void RepeatedMessageFieldGenerator::GenerateDestructorCode(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format("$field$.~WeakRepeatedPtrField();\n");
  } else {
    format("$field$.~RepeatedPtrField();\n");
  }
}

void RepeatedMessageFieldGenerator::GenerateSerializeWithCachedSizesToArray(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format(
        "for (auto it = this->$field$.pointer_begin(),\n"
        "          end = this->$field$.pointer_end(); it < end; ++it) {\n");
    if (descriptor_->type() == FieldDescriptor::TYPE_MESSAGE) {
      format(
          "  target = ::$proto_ns$::internal::WireFormatLite::\n"
          "    InternalWrite$declared_type$($number$, "
          "**it, (**it).GetCachedSize(), target, stream);\n");
    } else {
      format(
          "  target = stream->EnsureSpace(target);\n"
          "  target = ::$proto_ns$::internal::WireFormatLite::\n"
          "    InternalWrite$declared_type$($number$, **it, target, "
          "stream);\n");
    }
    format("}\n");
  } else {
    format(
        "for (unsigned i = 0,\n"
        "    n = static_cast<unsigned>(this->_internal_$name$_size());"
        " i < n; i++) {\n");
    if (descriptor_->type() == FieldDescriptor::TYPE_MESSAGE) {
      format(
          "  const auto& repfield = this->_internal_$name$(i);\n"
          "  target = ::$proto_ns$::internal::WireFormatLite::\n"
          "      InternalWrite$declared_type$($number$, "
          "repfield, repfield.GetCachedSize(), target, stream);\n"
          "}\n");
    } else {
      format(
          "  target = stream->EnsureSpace(target);\n"
          "  target = ::$proto_ns$::internal::WireFormatLite::\n"
          "    InternalWrite$declared_type$($number$, "
          "this->_internal_$name$(i), target, stream);\n"
          "}\n");
    }
  }
}

void RepeatedMessageFieldGenerator::GenerateByteSize(
    io::Printer* printer) const {
  Formatter format(printer, variables_);
  format(
      "total_size += $tag_size$UL * this->_internal_$name$_size();\n"
      "for (const auto& msg : this->$field$) {\n"
      "  total_size +=\n"
      "    ::$proto_ns$::internal::WireFormatLite::$declared_type$Size(msg);\n"
      "}\n");
}

void RepeatedMessageFieldGenerator::GenerateIsInitialized(
    io::Printer* printer) const {
  if (!has_required_fields_) return;

  Formatter format(printer, variables_);
  if (implicit_weak_field_) {
    format(
        "if (!::$proto_ns$::internal::AllAreInitializedWeak($field$.weak))\n"
        "  return false;\n");
  } else {
    format(
        "if (!::$proto_ns$::internal::AllAreInitialized($field$))\n"
        "  return false;\n");
  }
}
}  // namespace

std::unique_ptr<FieldGeneratorBase> MakeSinguarMessageGenerator(
    const FieldDescriptor* desc, const Options& options,
    MessageSCCAnalyzer* scc) {
  return absl::make_unique<MessageFieldGenerator>(desc, options, scc);
}

std::unique_ptr<FieldGeneratorBase> MakeRepeatedMessageGenerator(
    const FieldDescriptor* desc, const Options& options,
    MessageSCCAnalyzer* scc) {
  return absl::make_unique<RepeatedMessageFieldGenerator>(desc, options, scc);
}

std::unique_ptr<FieldGeneratorBase> MakeOneofMessageGenerator(
    const FieldDescriptor* desc, const Options& options,
    MessageSCCAnalyzer* scc) {
  return absl::make_unique<MessageOneofFieldGenerator>(desc, options, scc);
}

}  // namespace cpp
}  // namespace compiler
}  // namespace protobuf
}  // namespace google
