1 // Copyright 2007-2010 Baptiste Lepilleur
2 // Distributed under MIT license, or public domain if desired and
3 // recognized in your jurisdiction.
4 // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
5 
6 #ifndef JSON_WRITER_H_INCLUDED
7 #define JSON_WRITER_H_INCLUDED
8 
9 #if !defined(JSON_IS_AMALGAMATION)
10 #include "value.h"
11 #endif // if !defined(JSON_IS_AMALGAMATION)
12 #include <vector>
13 #include <string>
14 #include <ostream>
15 
16 // Disable warning C4251: <data member>: <type> needs to have dll-interface to
17 // be used by...
18 #if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
19 #pragma warning(push)
20 #pragma warning(disable : 4251)
21 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
22 
23 #pragma pack(push, 8)
24 
25 namespace Json {
26 
27 class Value;
28 
29 /**
30 
31 Usage:
32 \code
33   using namespace Json;
34   void writeToStdout(StreamWriter::Factory const& factory, Value const& value) {
35     std::unique_ptr<StreamWriter> const writer(
36       factory.newStreamWriter());
37     writer->write(value, &std::cout);
38     std::cout << std::endl;  // add lf and flush
39   }
40 \endcode
41 */
42 class JSON_API StreamWriter {
43 protected:
44   JSONCPP_OSTREAM* sout_;  // not owned; will not delete
45 public:
46   StreamWriter();
47   virtual ~StreamWriter();
48   /** Write Value into document as configured in sub-class.
49       Do not take ownership of sout, but maintain a reference during function.
50       \pre sout != NULL
51       \return zero on success (For now, we always return zero, so check the stream instead.)
52       \throw std::exception possibly, depending on configuration
53    */
54   virtual int write(Value const& root, JSONCPP_OSTREAM* sout) = 0;
55 
56   /** \brief A simple abstract factory.
57    */
58   class JSON_API Factory {
59   public:
60     virtual ~Factory();
61     /** \brief Allocate a CharReader via operator new().
62      * \throw std::exception if something goes wrong (e.g. invalid settings)
63      */
64     virtual StreamWriter* newStreamWriter() const = 0;
65   };  // Factory
66 };  // StreamWriter
67 
68 /** \brief Write into stringstream, then return string, for convenience.
69  * A StreamWriter will be created from the factory, used, and then deleted.
70  */
71 JSONCPP_STRING JSON_API writeString(StreamWriter::Factory const& factory, Value const& root);
72 
73 
74 /** \brief Build a StreamWriter implementation.
75 
76 Usage:
77 \code
78   using namespace Json;
79   Value value = ...;
80   StreamWriterBuilder builder;
81   builder["commentStyle"] = "None";
82   builder["indentation"] = "   ";  // or whatever you like
83   std::unique_ptr<Json::StreamWriter> writer(
84       builder.newStreamWriter());
85   writer->write(value, &std::cout);
86   std::cout << std::endl;  // add lf and flush
87 \endcode
88 */
89 class JSON_API StreamWriterBuilder : public StreamWriter::Factory {
90 public:
91   // Note: We use a Json::Value so that we can add data-members to this class
92   // without a major version bump.
93   /** Configuration of this builder.
94     Available settings (case-sensitive):
95     - "commentStyle": "None" or "All"
96     - "indentation":  "<anything>"
97     - "enableYAMLCompatibility": false or true
98       - slightly change the whitespace around colons
99     - "dropNullPlaceholders": false or true
100       - Drop the "null" string from the writer's output for nullValues.
101         Strictly speaking, this is not valid JSON. But when the output is being
102         fed to a browser's Javascript, it makes for smaller output and the
103         browser can handle the output just fine.
104     - "useSpecialFloats": false or true
105       - If true, outputs non-finite floating point values in the following way:
106         NaN values as "NaN", positive infinity as "Infinity", and negative infinity
107         as "-Infinity".
108 
109     You can examine 'settings_` yourself
110     to see the defaults. You can also write and read them just like any
111     JSON Value.
112     \sa setDefaults()
113     */
114   Json::Value settings_;
115 
116   StreamWriterBuilder();
117   ~StreamWriterBuilder() JSONCPP_OVERRIDE;
118 
119   /**
120    * \throw std::exception if something goes wrong (e.g. invalid settings)
121    */
122   StreamWriter* newStreamWriter() const JSONCPP_OVERRIDE;
123 
124   /** \return true if 'settings' are legal and consistent;
125    *   otherwise, indicate bad settings via 'invalid'.
126    */
127   bool validate(Json::Value* invalid) const;
128   /** A simple way to update a specific setting.
129    */
130   Value& operator[](JSONCPP_STRING key);
131 
132   /** Called by ctor, but you can use this to reset settings_.
133    * \pre 'settings' != NULL (but Json::null is fine)
134    * \remark Defaults:
135    * \snippet src/lib_json/json_writer.cpp StreamWriterBuilderDefaults
136    */
137   static void setDefaults(Json::Value* settings);
138 };
139 
140 /** \brief Abstract class for writers.
141  * \deprecated Use StreamWriter. (And really, this is an implementation detail.)
142  */
143 class JSON_API Writer {
144 public:
145   virtual ~Writer();
146 
147   virtual JSONCPP_STRING write(const Value& root) = 0;
148 };
149 
150 /** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format
151  *without formatting (not human friendly).
152  *
153  * The JSON document is written in a single line. It is not intended for 'human'
154  *consumption,
155  * but may be usefull to support feature such as RPC where bandwith is limited.
156  * \sa Reader, Value
157  * \deprecated Use StreamWriterBuilder.
158  */
159 class JSON_API FastWriter : public Writer {
160 
161 public:
162   FastWriter();
~FastWriter()163   ~FastWriter() JSONCPP_OVERRIDE {}
164 
165   void enableYAMLCompatibility();
166 
167   /** \brief Drop the "null" string from the writer's output for nullValues.
168    * Strictly speaking, this is not valid JSON. But when the output is being
169    * fed to a browser's Javascript, it makes for smaller output and the
170    * browser can handle the output just fine.
171    */
172   void dropNullPlaceholders();
173 
174   void omitEndingLineFeed();
175 
176 public: // overridden from Writer
177   JSONCPP_STRING write(const Value& root) JSONCPP_OVERRIDE;
178 
179 private:
180   void writeValue(const Value& value);
181 
182   JSONCPP_STRING document_;
183   bool yamlCompatiblityEnabled_;
184   bool dropNullPlaceholders_;
185   bool omitEndingLineFeed_;
186 };
187 
188 /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
189  *human friendly way.
190  *
191  * The rules for line break and indent are as follow:
192  * - Object value:
193  *     - if empty then print {} without indent and line break
194  *     - if not empty the print '{', line break & indent, print one value per
195  *line
196  *       and then unindent and line break and print '}'.
197  * - Array value:
198  *     - if empty then print [] without indent and line break
199  *     - if the array contains no object value, empty array or some other value
200  *types,
201  *       and all the values fit on one lines, then print the array on a single
202  *line.
203  *     - otherwise, it the values do not fit on one line, or the array contains
204  *       object or non empty array, then print one value per line.
205  *
206  * If the Value have comments then they are outputed according to their
207  *#CommentPlacement.
208  *
209  * \sa Reader, Value, Value::setComment()
210  * \deprecated Use StreamWriterBuilder.
211  */
212 class JSON_API StyledWriter : public Writer {
213 public:
214   StyledWriter();
~StyledWriter()215   ~StyledWriter() JSONCPP_OVERRIDE {}
216 
217 public: // overridden from Writer
218   /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
219    * \param root Value to serialize.
220    * \return String containing the JSON document that represents the root value.
221    */
222   JSONCPP_STRING write(const Value& root) JSONCPP_OVERRIDE;
223 
224 private:
225   void writeValue(const Value& value);
226   void writeArrayValue(const Value& value);
227   bool isMultineArray(const Value& value);
228   void pushValue(const JSONCPP_STRING& value);
229   void writeIndent();
230   void writeWithIndent(const JSONCPP_STRING& value);
231   void indent();
232   void unindent();
233   void writeCommentBeforeValue(const Value& root);
234   void writeCommentAfterValueOnSameLine(const Value& root);
235   bool hasCommentForValue(const Value& value);
236   static JSONCPP_STRING normalizeEOL(const JSONCPP_STRING& text);
237 
238   typedef std::vector<JSONCPP_STRING> ChildValues;
239 
240   ChildValues childValues_;
241   JSONCPP_STRING document_;
242   JSONCPP_STRING indentString_;
243   unsigned int rightMargin_;
244   unsigned int indentSize_;
245   bool addChildValues_;
246 };
247 
248 /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
249  human friendly way,
250      to a stream rather than to a string.
251  *
252  * The rules for line break and indent are as follow:
253  * - Object value:
254  *     - if empty then print {} without indent and line break
255  *     - if not empty the print '{', line break & indent, print one value per
256  line
257  *       and then unindent and line break and print '}'.
258  * - Array value:
259  *     - if empty then print [] without indent and line break
260  *     - if the array contains no object value, empty array or some other value
261  types,
262  *       and all the values fit on one lines, then print the array on a single
263  line.
264  *     - otherwise, it the values do not fit on one line, or the array contains
265  *       object or non empty array, then print one value per line.
266  *
267  * If the Value have comments then they are outputed according to their
268  #CommentPlacement.
269  *
270  * \param indentation Each level will be indented by this amount extra.
271  * \sa Reader, Value, Value::setComment()
272  * \deprecated Use StreamWriterBuilder.
273  */
274 class JSON_API StyledStreamWriter {
275 public:
276   StyledStreamWriter(JSONCPP_STRING indentation = "\t");
~StyledStreamWriter()277   ~StyledStreamWriter() {}
278 
279 public:
280   /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
281    * \param out Stream to write to. (Can be ostringstream, e.g.)
282    * \param root Value to serialize.
283    * \note There is no point in deriving from Writer, since write() should not
284    * return a value.
285    */
286   void write(JSONCPP_OSTREAM& out, const Value& root);
287 
288 private:
289   void writeValue(const Value& value);
290   void writeArrayValue(const Value& value);
291   bool isMultineArray(const Value& value);
292   void pushValue(const JSONCPP_STRING& value);
293   void writeIndent();
294   void writeWithIndent(const JSONCPP_STRING& value);
295   void indent();
296   void unindent();
297   void writeCommentBeforeValue(const Value& root);
298   void writeCommentAfterValueOnSameLine(const Value& root);
299   bool hasCommentForValue(const Value& value);
300   static JSONCPP_STRING normalizeEOL(const JSONCPP_STRING& text);
301 
302   typedef std::vector<JSONCPP_STRING> ChildValues;
303 
304   ChildValues childValues_;
305   JSONCPP_OSTREAM* document_;
306   JSONCPP_STRING indentString_;
307   unsigned int rightMargin_;
308   JSONCPP_STRING indentation_;
309   bool addChildValues_ : 1;
310   bool indented_ : 1;
311 };
312 
313 #if defined(JSON_HAS_INT64)
314 JSONCPP_STRING JSON_API valueToString(Int value);
315 JSONCPP_STRING JSON_API valueToString(UInt value);
316 #endif // if defined(JSON_HAS_INT64)
317 JSONCPP_STRING JSON_API valueToString(LargestInt value);
318 JSONCPP_STRING JSON_API valueToString(LargestUInt value);
319 JSONCPP_STRING JSON_API valueToString(double value);
320 JSONCPP_STRING JSON_API valueToString(bool value);
321 JSONCPP_STRING JSON_API valueToQuotedString(const char* value);
322 
323 /// \brief Output using the StyledStreamWriter.
324 /// \see Json::operator>>()
325 JSON_API JSONCPP_OSTREAM& operator<<(JSONCPP_OSTREAM&, const Value& root);
326 
327 } // namespace Json
328 
329 #pragma pack(pop)
330 
331 #if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
332 #pragma warning(pop)
333 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
334 
335 #endif // JSON_WRITER_H_INCLUDED
336