1// Protocol Buffers - Google's data interchange format
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30
31#ifndef GOOGLE_PROTOBUF_UTIL_CONVERTER_OBJECT_WRITER_H__
32#define GOOGLE_PROTOBUF_UTIL_CONVERTER_OBJECT_WRITER_H__
33
34#include <google/protobuf/stubs/common.h>
35#include <google/protobuf/stubs/stringpiece.h>
36
37namespace google {
38namespace protobuf {
39namespace util {
40namespace converter {
41
42class DataPiece;
43
44// An ObjectWriter is an interface for writing a stream of events
45// representing objects and collections. Implementation of this
46// interface can be used to write an object stream to an in-memory
47// structure, protobufs, JSON, XML, or any other output format
48// desired. The ObjectSource interface is typically used as the
49// source of an object stream.
50//
51// See JsonObjectWriter for a sample implementation of ObjectWriter
52// and its use.
53//
54// Derived classes could be thread-unsafe.
55//
56// TODO(xinb): seems like a prime candidate to apply the RAII paradigm
57// and get rid the need to call EndXXX().
58class LIBPROTOBUF_EXPORT ObjectWriter {
59 public:
60  virtual ~ObjectWriter() {}
61
62  // Starts an object. If the name is empty, the object will not be named.
63  virtual ObjectWriter* StartObject(StringPiece name) = 0;
64
65  // Ends an object.
66  virtual ObjectWriter* EndObject() = 0;
67
68  // Starts a list. If the name is empty, the list will not be named.
69  virtual ObjectWriter* StartList(StringPiece name) = 0;
70
71  // Ends a list.
72  virtual ObjectWriter* EndList() = 0;
73
74  // Renders a boolean value.
75  virtual ObjectWriter* RenderBool(StringPiece name, bool value) = 0;
76
77  // Renders an 32-bit integer value.
78  virtual ObjectWriter* RenderInt32(StringPiece name, int32 value) = 0;
79
80  // Renders an 32-bit unsigned integer value.
81  virtual ObjectWriter* RenderUint32(StringPiece name, uint32 value) = 0;
82
83  // Renders a 64-bit integer value.
84  virtual ObjectWriter* RenderInt64(StringPiece name, int64 value) = 0;
85
86  // Renders an 64-bit unsigned integer value.
87  virtual ObjectWriter* RenderUint64(StringPiece name, uint64 value) = 0;
88
89  // Renders a double value.
90  virtual ObjectWriter* RenderDouble(StringPiece name, double value) = 0;
91
92  // Renders a float value.
93  virtual ObjectWriter* RenderFloat(StringPiece name, float value) = 0;
94
95  // Renders a StringPiece value. This is for rendering strings.
96  virtual ObjectWriter* RenderString(StringPiece name, StringPiece value) = 0;
97
98  // Renders a bytes value.
99  virtual ObjectWriter* RenderBytes(StringPiece name, StringPiece value) = 0;
100
101  // Renders a Null value.
102  virtual ObjectWriter* RenderNull(StringPiece name) = 0;
103
104  // Renders a DataPiece object to a ObjectWriter.
105  static void RenderDataPieceTo(const DataPiece& data, StringPiece name,
106                                ObjectWriter* ow);
107
108  // Indicates whether this ObjectWriter has completed writing the root message,
109  // usually this means writing of one complete object. Subclasses must override
110  // this behavior appropriately.
111  virtual bool done() { return false; }
112
113  void set_use_strict_base64_decoding(bool value) {
114    use_strict_base64_decoding_ = value;
115  }
116
117  bool use_strict_base64_decoding() const {
118    return use_strict_base64_decoding_;
119  }
120
121 protected:
122  ObjectWriter() : use_strict_base64_decoding_(true) {}
123
124 private:
125  // If set to true, we use the stricter version of base64 decoding for byte
126  // fields by making sure decoded version encodes back to the original string.
127  bool use_strict_base64_decoding_;
128
129  // Do not add any data members to this class.
130  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ObjectWriter);
131};
132
133}  // namespace converter
134}  // namespace util
135}  // namespace protobuf
136
137}  // namespace google
138#endif  // GOOGLE_PROTOBUF_UTIL_CONVERTER_OBJECT_WRITER_H__
139