protobuf/src/google/protobuf/compiler/javanano/javanano_field.cc

// Protocol Buffers - Google's data interchange format
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// Author: kenton@google.com (Kenton Varda)
//  Based on original Protocol Buffers design by
//  Sanjay Ghemawat, Jeff Dean, and others.

#include <google/protobuf/compiler/javanano/javanano_field.h>
#include <google/protobuf/compiler/javanano/javanano_helpers.h>
#include <google/protobuf/compiler/javanano/javanano_primitive_field.h>
#include <google/protobuf/compiler/javanano/javanano_enum_field.h>
#include <google/protobuf/compiler/javanano/javanano_message_field.h>
#include <google/protobuf/stubs/common.h>

namespace google {
namespace protobuf {
namespace compiler {
namespace javanano {

FieldGenerator::~FieldGenerator() {}

bool FieldGenerator::SavedDefaultNeeded() const {
  // No saved default for this field by default.
  // Subclasses whose instances may need saved defaults will override this
  // and return the appropriate value.
  return false;
}

void FieldGenerator::GenerateInitSavedDefaultCode(io::Printer* printer) const {
  // No saved default for this field by default.
  // Subclasses whose instances may need saved defaults will override this
  // and generate the appropriate init code to the printer.
}

void FieldGenerator::GenerateMergingCodeFromPacked(io::Printer* printer) const {
  // Reaching here indicates a bug. Cases are:
  //   - This FieldGenerator should support packing, but this method should be
  //     overridden.
  //   - This FieldGenerator doesn't support packing, and this method should
  //     never have been called.
  GOOGLE_LOG(FATAL) << "GenerateParsingCodeFromPacked() "
             << "called on field generator that does not support packing.";
}

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

FieldGeneratorMap::FieldGeneratorMap(
    const Descriptor* descriptor, const Params &params)
  : descriptor_(descriptor),
    field_generators_(
      new scoped_ptr<FieldGenerator>[descriptor->field_count()]) {

  int next_has_bit_index = 0;
  bool saved_defaults_needed = false;
  // Construct all the FieldGenerators.
  for (int i = 0; i < descriptor->field_count(); i++) {
    FieldGenerator* field_generator = MakeGenerator(
        descriptor->field(i), params, &next_has_bit_index);
    saved_defaults_needed = saved_defaults_needed
        || field_generator->SavedDefaultNeeded();
    field_generators_[i].reset(field_generator);
  }
  total_bits_ = next_has_bit_index;
  saved_defaults_needed_ = saved_defaults_needed;
}

FieldGenerator* FieldGeneratorMap::MakeGenerator(const FieldDescriptor* field,
    const Params &params, int* next_has_bit_index) {
  JavaType java_type = GetJavaType(field);
  if (field->is_repeated()) {
    switch (java_type) {
      case JAVATYPE_MESSAGE:
        return new RepeatedMessageFieldGenerator(field, params);
      case JAVATYPE_ENUM:
        return new RepeatedEnumFieldGenerator(field, params);
      default:
        return new RepeatedPrimitiveFieldGenerator(field, params);
    }
  } else if (params.optional_field_accessors() && field->is_optional()
      && java_type != JAVATYPE_MESSAGE) {
    // We need a has-bit for each primitive/enum field because their default
    // values could be same as explicitly set values. But we don't need it
    // for a message field because they have no defaults and Nano uses 'null'
    // for unset messages, which cannot be set explicitly.
    switch (java_type) {
      case JAVATYPE_ENUM:
        return new AccessorEnumFieldGenerator(
            field, params, (*next_has_bit_index)++);
      default:
        return new AccessorPrimitiveFieldGenerator(
            field, params, (*next_has_bit_index)++);
    }
  } else {
    switch (java_type) {
      case JAVATYPE_MESSAGE:
        return new MessageFieldGenerator(field, params);
      case JAVATYPE_ENUM:
        return new EnumFieldGenerator(field, params);
      default:
        return new PrimitiveFieldGenerator(field, params);
    }
  }
}

FieldGeneratorMap::~FieldGeneratorMap() {}

const FieldGenerator& FieldGeneratorMap::get(
    const FieldDescriptor* field) const {
  GOOGLE_CHECK_EQ(field->containing_type(), descriptor_);
  return *field_generators_[field->index()];
}

}  // namespace javanano
}  // namespace compiler
}  // namespace protobuf
}  // namespace google