src/google/protobuf/util/json_util.h

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// 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.
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
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// Utility functions to convert between protobuf binary format and proto3 JSON
// format.
#ifndef GOOGLE_PROTOBUF_UTIL_JSON_UTIL_H__
#define GOOGLE_PROTOBUF_UTIL_JSON_UTIL_H__

#include <google/protobuf/message.h>
#include <google/protobuf/util/type_resolver.h>
#include <google/protobuf/stubs/bytestream.h>

namespace google {
namespace protobuf {
namespace io {
class ZeroCopyInputStream;
class ZeroCopyOutputStream;
}  // namespace io
namespace util {

struct JsonParseOptions {
  // Whether to ignore unknown JSON fields during parsing
  bool ignore_unknown_fields;

  JsonParseOptions() : ignore_unknown_fields(false) {}
};

struct JsonPrintOptions {
  // Whether to add spaces, line breaks and indentation to make the JSON output
  // easy to read.
  bool add_whitespace;
  // Whether to always print primitive fields. By default proto3 primitive
  // fields with default values will be omitted in JSON output. For example, an
  // int32 field set to 0 will be omitted. Set this flag to true will override
  // the default behavior and print primitive fields regardless of their values.
  bool always_print_primitive_fields;
  // Whether to always print enums as ints. By default they are rendered as
  // strings.
  bool always_print_enums_as_ints;
  // Whether to preserve proto field names
  bool preserve_proto_field_names;

  JsonPrintOptions()
      : add_whitespace(false),
        always_print_primitive_fields(false),
        always_print_enums_as_ints(false),
        preserve_proto_field_names(false) {}
};

// DEPRECATED. Use JsonPrintOptions instead.
typedef JsonPrintOptions JsonOptions;

// Converts from protobuf message to JSON. This is a simple wrapper of
// BinaryToJsonString(). It will use the DescriptorPool of the passed-in
// message to resolve Any types.
LIBPROTOBUF_EXPORT util::Status MessageToJsonString(const Message& message,
                                   string* output,
                                   const JsonOptions& options);

inline util::Status MessageToJsonString(const Message& message,
                                          string* output) {
  return MessageToJsonString(message, output, JsonOptions());
}

// Converts from JSON to protobuf message. This is a simple wrapper of
// JsonStringToBinary(). It will use the DescriptorPool of the passed-in
// message to resolve Any types.
LIBPROTOBUF_EXPORT util::Status JsonStringToMessage(const string& input,
                                   Message* message,
                                   const JsonParseOptions& options);

inline util::Status JsonStringToMessage(const string& input,
                                          Message* message) {
  return JsonStringToMessage(input, message, JsonParseOptions());
}

// Converts protobuf binary data to JSON.
// The conversion will fail if:
//   1. TypeResolver fails to resolve a type.
//   2. input is not valid protobuf wire format, or conflicts with the type
//      information returned by TypeResolver.
// Note that unknown fields will be discarded silently.
LIBPROTOBUF_EXPORT util::Status BinaryToJsonStream(
    TypeResolver* resolver,
    const string& type_url,
    io::ZeroCopyInputStream* binary_input,
    io::ZeroCopyOutputStream* json_output,
    const JsonPrintOptions& options);

inline util::Status BinaryToJsonStream(
    TypeResolver* resolver, const string& type_url,
    io::ZeroCopyInputStream* binary_input,
    io::ZeroCopyOutputStream* json_output) {
  return BinaryToJsonStream(resolver, type_url, binary_input, json_output,
                            JsonPrintOptions());
}

LIBPROTOBUF_EXPORT util::Status BinaryToJsonString(
    TypeResolver* resolver,
    const string& type_url,
    const string& binary_input,
    string* json_output,
    const JsonPrintOptions& options);

inline util::Status BinaryToJsonString(TypeResolver* resolver,
                                         const string& type_url,
                                         const string& binary_input,
                                         string* json_output) {
  return BinaryToJsonString(resolver, type_url, binary_input, json_output,
                            JsonPrintOptions());
}

// Converts JSON data to protobuf binary format.
// The conversion will fail if:
//   1. TypeResolver fails to resolve a type.
//   2. input is not valid JSON format, or conflicts with the type
//      information returned by TypeResolver.
LIBPROTOBUF_EXPORT util::Status JsonToBinaryStream(
    TypeResolver* resolver,
    const string& type_url,
    io::ZeroCopyInputStream* json_input,
    io::ZeroCopyOutputStream* binary_output,
    const JsonParseOptions& options);

inline util::Status JsonToBinaryStream(
    TypeResolver* resolver,
    const string& type_url,
    io::ZeroCopyInputStream* json_input,
    io::ZeroCopyOutputStream* binary_output) {
  return JsonToBinaryStream(resolver, type_url, json_input, binary_output,
                            JsonParseOptions());
}

LIBPROTOBUF_EXPORT util::Status JsonToBinaryString(
    TypeResolver* resolver,
    const string& type_url,
    const string& json_input,
    string* binary_output,
    const JsonParseOptions& options);

inline util::Status JsonToBinaryString(
    TypeResolver* resolver,
    const string& type_url,
    const string& json_input,
    string* binary_output) {
  return JsonToBinaryString(resolver, type_url, json_input, binary_output,
                            JsonParseOptions());
}

namespace internal {
// Internal helper class. Put in the header so we can write unit-tests for it.
class LIBPROTOBUF_EXPORT ZeroCopyStreamByteSink : public strings::ByteSink {
 public:
  explicit ZeroCopyStreamByteSink(io::ZeroCopyOutputStream* stream)
      : stream_(stream), buffer_(NULL), buffer_size_(0) {}
  ~ZeroCopyStreamByteSink();

  virtual void Append(const char* bytes, size_t len);

 private:
  io::ZeroCopyOutputStream* stream_;
  void* buffer_;
  int buffer_size_;

  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ZeroCopyStreamByteSink);
};
}  // namespace internal

}  // namespace util
}  // namespace protobuf

}  // namespace google
#endif  // GOOGLE_PROTOBUF_UTIL_JSON_UTIL_H__