rippled/modules/ripple_basics/json/json_writer.h

//------------------------------------------------------------------------------
/*
    Copyright (c) 2011-2013, OpenCoin, Inc.
*/
//==============================================================================

#ifndef JSON_WRITER_H_INCLUDED
#define JSON_WRITER_H_INCLUDED

namespace Json
{

class Value;

/** \brief Abstract class for writers.
 */
class JSON_API Writer
{
public:
    virtual ~Writer ();

    virtual std::string write ( const Value& root ) = 0;
};

/** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format without formatting (not human friendly).
 *
 * The JSON document is written in a single line. It is not intended for 'human' consumption,
 * but may be usefull to support feature such as RPC where bandwith is limited.
 * \sa Reader, Value
 */
class JSON_API FastWriter : public Writer
{
public:
    FastWriter ();
    virtual ~FastWriter () {}

    void enableYAMLCompatibility ();

public: // overridden from Writer
    virtual std::string write ( const Value& root );

private:
    void writeValue ( const Value& value );

    std::string document_;
    bool yamlCompatiblityEnabled_;
};

/** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way.
 *
 * The rules for line break and indent are as follow:
 * - Object value:
 *     - if empty then print {} without indent and line break
 *     - if not empty the print '{', line break & indent, print one value per line
 *       and then unindent and line break and print '}'.
 * - Array value:
 *     - if empty then print [] without indent and line break
 *     - if the array contains no object value, empty array or some other value types,
 *       and all the values fit on one lines, then print the array on a single line.
 *     - otherwise, it the values do not fit on one line, or the array contains
 *       object or non empty array, then print one value per line.
 *
 * If the Value have comments then they are outputed according to their #CommentPlacement.
 *
 * \sa Reader, Value, Value::setComment()
 */
class JSON_API StyledWriter: public Writer
{
public:
    StyledWriter ();
    virtual ~StyledWriter () {}

public: // overridden from Writer
    /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
     * \param root Value to serialize.
     * \return String containing the JSON document that represents the root value.
     */
    virtual std::string write ( const Value& root );

private:
    void writeValue ( const Value& value );
    void writeArrayValue ( const Value& value );
    bool isMultineArray ( const Value& value );
    void pushValue ( const std::string& value );
    void writeIndent ();
    void writeWithIndent ( const std::string& value );
    void indent ();
    void unindent ();
    void writeCommentBeforeValue ( const Value& root );
    void writeCommentAfterValueOnSameLine ( const Value& root );
    bool hasCommentForValue ( const Value& value );
    static std::string normalizeEOL ( const std::string& text );

    typedef std::vector<std::string> ChildValues;

    ChildValues childValues_;
    std::string document_;
    std::string indentString_;
    int rightMargin_;
    int indentSize_;
    bool addChildValues_;
};

/** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way,
     to a stream rather than to a string.
 *
 * The rules for line break and indent are as follow:
 * - Object value:
 *     - if empty then print {} without indent and line break
 *     - if not empty the print '{', line break & indent, print one value per line
 *       and then unindent and line break and print '}'.
 * - Array value:
 *     - if empty then print [] without indent and line break
 *     - if the array contains no object value, empty array or some other value types,
 *       and all the values fit on one lines, then print the array on a single line.
 *     - otherwise, it the values do not fit on one line, or the array contains
 *       object or non empty array, then print one value per line.
 *
 * If the Value have comments then they are outputed according to their #CommentPlacement.
 *
 * \param indentation Each level will be indented by this amount extra.
 * \sa Reader, Value, Value::setComment()
 */
class JSON_API StyledStreamWriter
{
public:
    StyledStreamWriter ( std::string indentation = "\t" );
    ~StyledStreamWriter () {}

public:
    /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
     * \param out Stream to write to. (Can be ostringstream, e.g.)
     * \param root Value to serialize.
     * \note There is no point in deriving from Writer, since write() should not return a value.
     */
    void write ( std::ostream& out, const Value& root );

private:
    void writeValue ( const Value& value );
    void writeArrayValue ( const Value& value );
    bool isMultineArray ( const Value& value );
    void pushValue ( const std::string& value );
    void writeIndent ();
    void writeWithIndent ( const std::string& value );
    void indent ();
    void unindent ();
    void writeCommentBeforeValue ( const Value& root );
    void writeCommentAfterValueOnSameLine ( const Value& root );
    bool hasCommentForValue ( const Value& value );
    static std::string normalizeEOL ( const std::string& text );

    typedef std::vector<std::string> ChildValues;

    ChildValues childValues_;
    std::ostream* document_;
    std::string indentString_;
    int rightMargin_;
    std::string indentation_;
    bool addChildValues_;
};

std::string JSON_API valueToString ( Int value );
std::string JSON_API valueToString ( UInt value );
std::string JSON_API valueToString ( double value );
std::string JSON_API valueToString ( bool value );
std::string JSON_API valueToQuotedString ( const char* value );

/// \brief Output using the StyledStreamWriter.
/// \see Json::operator>>()
std::ostream& operator<< ( std::ostream&, const Value& root );

} // namespace Json



#endif // JSON_WRITER_H_INCLUDED