gcc/json.h

   1 /* JSON trees
   2    Copyright (C) 2017-2019 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 number;
  43   class string;
  44   class literal;
  45
  46 /* An enum for discriminating the subclasses of json::value.  */
  47
  48 enum kind
  49 {
  50   /* class json::object.  */
  51   JSON_OBJECT,
  52
  53   /* class json::array.  */
  54   JSON_ARRAY,
  55
  56   /* class json::number.  */
  57   JSON_NUMBER,
  58
  59   /* class json::string.  */
  60   JSON_STRING,
  61
  62   /* class json::literal uses these three values to identify the
  63      particular literal.  */
  64   JSON_TRUE,
  65   JSON_FALSE,
  66   JSON_NULL
  67 };
  68
  69 /* Base class of JSON value.  */
  70
  71 class value
  72 {
  73  public:
  74   virtual ~value () {}
  75   virtual enum kind get_kind () const = 0;
  76   virtual void print (pretty_printer *pp) const = 0;
  77
  78   void dump (FILE *) const;
  79 };
  80
  81 /* Subclass of value for objects: an unordered collection of
  82    key/value pairs.  */
  83
  84 class object : public value
  85 {
  86  public:
  87   ~object ();
  88
  89   enum kind get_kind () const FINAL OVERRIDE { return JSON_OBJECT; }
  90   void print (pretty_printer *pp) const FINAL OVERRIDE;
  91
  92   void set (const char *key, value *v);
  93   value *get (const char *key) const;
  94
  95  private:
  96   typedef hash_map <char *, value *,
  97     simple_hashmap_traits<nofree_string_hash, value *> > map_t;
  98   map_t m_map;
  99 };
 100
 101 /* Subclass of value for arrays.  */
 102
 103 class array : public value
 104 {
 105  public:
 106   ~array ();
 107
 108   enum kind get_kind () const FINAL OVERRIDE { return JSON_ARRAY; }
 109   void print (pretty_printer *pp) const FINAL OVERRIDE;
 110
 111   void append (value *v);
 112
 113  private:
 114   auto_vec<value *> m_elements;
 115 };
 116
 117 /* Subclass of value for numbers.  */
 118
 119 class number : public value
 120 {
 121  public:
 122   number (double value) : m_value (value) {}
 123
 124   enum kind get_kind () const FINAL OVERRIDE { return JSON_NUMBER; }
 125   void print (pretty_printer *pp) const FINAL OVERRIDE;
 126
 127   double get () const { return m_value; }
 128
 129  private:
 130   double m_value;
 131 };
 132
 133 /* Subclass of value for strings.  */
 134
 135 class string : public value
 136 {
 137  public:
 138   string (const char *utf8);
 139   ~string () { free (m_utf8); }
 140
 141   enum kind get_kind () const FINAL OVERRIDE { return JSON_STRING; }
 142   void print (pretty_printer *pp) const FINAL OVERRIDE;
 143
 144   const char *get_string () const { return m_utf8; }
 145
 146  private:
 147   char *m_utf8;
 148 };
 149
 150 /* Subclass of value for the three JSON literals "true", "false",
 151    and "null".  */
 152
 153 class literal : public value
 154 {
 155  public:
 156   literal (enum kind kind) : m_kind (kind) {}
 157
 158   /* Construct literal for a boolean value.  */
 159   literal (bool value): m_kind (value ? JSON_TRUE : JSON_FALSE) {}
 160
 161   enum kind get_kind () const FINAL OVERRIDE { return m_kind; }
 162   void print (pretty_printer *pp) const FINAL OVERRIDE;
 163
 164  private:
 165   enum kind m_kind;
 166 };
 167
 168 } // namespace json
 169
 170 #endif  /* GCC_JSON_H  */