gcc/json.h

   1 /* JSON trees
   2    Copyright (C) 2017-2020 Free Software Foundation, Inc.
   3    Contributed by David Malcolm <dmalcolm@redhat.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_JSON_H
  22 #define GCC_JSON_H
  23
  24 /* Implementation of JSON, a lightweight data-interchange format.
  25
  26    See http://www.json.org/
  27    and http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf
  28    and https://tools.ietf.org/html/rfc7159
  29
  30    Supports creating a DOM-like tree of json::value *, and then dumping
  31    json::value * to text.  */
  32
  33 namespace json
  34 {
  35
  36 /* Forward decls of json::value and its subclasses (using indentation
  37    to denote inheritance.  */
  38
  39 class value;
  40   class object;
  41   class array;
  42   class float_number;
  43   class integer_number;
  44   class string;
  45   class literal;
  46
  47 /* An enum for discriminating the subclasses of json::value.  */
  48
  49 enum kind
  50 {
  51   /* class json::object.  */
  52   JSON_OBJECT,
  53
  54   /* class json::array.  */
  55   JSON_ARRAY,
  56
  57   /* class json::integer_number.  */
  58   JSON_INTEGER,
  59
  60   /* class json::float_number.  */
  61   JSON_FLOAT,
  62
  63   /* class json::string.  */
  64   JSON_STRING,
  65
  66   /* class json::literal uses these three values to identify the
  67      particular literal.  */
  68   JSON_TRUE,
  69   JSON_FALSE,
  70   JSON_NULL
  71 };
  72
  73 /* Base class of JSON value.  */
  74
  75 class value
  76 {
  77  public:
  78   virtual ~value () {}
  79   virtual enum kind get_kind () const = 0;
  80   virtual void print (pretty_printer *pp) const = 0;
  81
  82   void dump (FILE *) const;
  83 };
  84
  85 /* Subclass of value for objects: an unordered collection of
  86    key/value pairs.  */
  87
  88 class object : public value
  89 {
  90  public:
  91   ~object ();
  92
  93   enum kind get_kind () const FINAL OVERRIDE { return JSON_OBJECT; }
  94   void print (pretty_printer *pp) const FINAL OVERRIDE;
  95
  96   void set (const char *key, value *v);
  97   value *get (const char *key) const;
  98
  99  private:
 100   typedef hash_map <char *, value *,
 101     simple_hashmap_traits<nofree_string_hash, value *> > map_t;
 102   map_t m_map;
 103 };
 104
 105 /* Subclass of value for arrays.  */
 106
 107 class array : public value
 108 {
 109  public:
 110   ~array ();
 111
 112   enum kind get_kind () const FINAL OVERRIDE { return JSON_ARRAY; }
 113   void print (pretty_printer *pp) const FINAL OVERRIDE;
 114
 115   void append (value *v);
 116
 117  private:
 118   auto_vec<value *> m_elements;
 119 };
 120
 121 /* Subclass of value for floating-point numbers.  */
 122
 123 class float_number : public value
 124 {
 125  public:
 126   float_number (double value) : m_value (value) {}
 127
 128   enum kind get_kind () const FINAL OVERRIDE { return JSON_FLOAT; }
 129   void print (pretty_printer *pp) const FINAL OVERRIDE;
 130
 131   double get () const { return m_value; }
 132
 133  private:
 134   double m_value;
 135 };
 136
 137 /* Subclass of value for integer-valued numbers.  */
 138
 139 class integer_number : public value
 140 {
 141  public:
 142   integer_number (long value) : m_value (value) {}
 143
 144   enum kind get_kind () const FINAL OVERRIDE { return JSON_INTEGER; }
 145   void print (pretty_printer *pp) const FINAL OVERRIDE;
 146
 147   long get () const { return m_value; }
 148
 149  private:
 150   long m_value;
 151 };
 152
 153
 154 /* Subclass of value for strings.  */
 155
 156 class string : public value
 157 {
 158  public:
 159   string (const char *utf8);
 160   ~string () { free (m_utf8); }
 161
 162   enum kind get_kind () const FINAL OVERRIDE { return JSON_STRING; }
 163   void print (pretty_printer *pp) const FINAL OVERRIDE;
 164
 165   const char *get_string () const { return m_utf8; }
 166
 167  private:
 168   char *m_utf8;
 169 };
 170
 171 /* Subclass of value for the three JSON literals "true", "false",
 172    and "null".  */
 173
 174 class literal : public value
 175 {
 176  public:
 177   literal (enum kind kind) : m_kind (kind) {}
 178
 179   /* Construct literal for a boolean value.  */
 180   literal (bool value): m_kind (value ? JSON_TRUE : JSON_FALSE) {}
 181
 182   enum kind get_kind () const FINAL OVERRIDE { return m_kind; }
 183   void print (pretty_printer *pp) const FINAL OVERRIDE;
 184
 185  private:
 186   enum kind m_kind;
 187 };
 188
 189 } // namespace json
 190
 191 #endif  /* GCC_JSON_H  */