gcc/json.h

   1 /* JSON trees
   2    Copyright (C) 2017-2023 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 /* TODO: `libcpp/mkdeps.cc` wants JSON writing support for p1689r5 output;
  34    extract this code and move to libiberty.  */
  35
  36 namespace json
  37 {
  38
  39 /* Forward decls of json::value and its subclasses (using indentation
  40    to denote inheritance.  */
  41
  42 class value;
  43   class object;
  44   class array;
  45   class float_number;
  46   class integer_number;
  47   class string;
  48   class literal;
  49
  50 /* An enum for discriminating the subclasses of json::value.  */
  51
  52 enum kind
  53 {
  54   /* class json::object.  */
  55   JSON_OBJECT,
  56
  57   /* class json::array.  */
  58   JSON_ARRAY,
  59
  60   /* class json::integer_number.  */
  61   JSON_INTEGER,
  62
  63   /* class json::float_number.  */
  64   JSON_FLOAT,
  65
  66   /* class json::string.  */
  67   JSON_STRING,
  68
  69   /* class json::literal uses these three values to identify the
  70      particular literal.  */
  71   JSON_TRUE,
  72   JSON_FALSE,
  73   JSON_NULL
  74 };
  75
  76 /* Base class of JSON value.  */
  77
  78 class value
  79 {
  80  public:
  81   virtual ~value () {}
  82   virtual enum kind get_kind () const = 0;
  83   virtual void print (pretty_printer *pp, bool formatted) const = 0;
  84
  85   void dump (FILE *, bool formatted) const;
  86 };
  87
  88 /* Subclass of value for objects: a collection of key/value pairs
  89    preserving the ordering in which keys were inserted.
  90
  91    Preserving the order eliminates non-determinism in the output,
  92    making it easier for the user to compare repeated invocations.  */
  93
  94 class object : public value
  95 {
  96  public:
  97   ~object ();
  98
  99   enum kind get_kind () const final override { return JSON_OBJECT; }
 100   void print (pretty_printer *pp, bool formatted) const final override;
 101
 102   void set (const char *key, value *v);
 103   value *get (const char *key) const;
 104
 105   void set_string (const char *key, const char *utf8_value);
 106   void set_integer (const char *key, long v);
 107   void set_float (const char *key, double v);
 108
 109   /* Set to literal true/false.  */
 110   void set_bool (const char *key, bool v);
 111
 112  private:
 113   typedef hash_map <char *, value *,
 114     simple_hashmap_traits<nofree_string_hash, value *> > map_t;
 115   map_t m_map;
 116
 117   /* Keep track of order in which keys were inserted.  */
 118   auto_vec <const char *> m_keys;
 119 };
 120
 121 /* Subclass of value for arrays.  */
 122
 123 class array : public value
 124 {
 125  public:
 126   ~array ();
 127
 128   enum kind get_kind () const final override { return JSON_ARRAY; }
 129   void print (pretty_printer *pp, bool formatted) const final override;
 130
 131   void append (value *v);
 132
 133  private:
 134   auto_vec<value *> m_elements;
 135 };
 136
 137 /* Subclass of value for floating-point numbers.  */
 138
 139 class float_number : public value
 140 {
 141  public:
 142   float_number (double value) : m_value (value) {}
 143
 144   enum kind get_kind () const final override { return JSON_FLOAT; }
 145   void print (pretty_printer *pp, bool formatted) const final override;
 146
 147   double get () const { return m_value; }
 148
 149  private:
 150   double m_value;
 151 };
 152
 153 /* Subclass of value for integer-valued numbers.  */
 154
 155 class integer_number : public value
 156 {
 157  public:
 158   integer_number (long value) : m_value (value) {}
 159
 160   enum kind get_kind () const final override { return JSON_INTEGER; }
 161   void print (pretty_printer *pp, bool formatted) const final override;
 162
 163   long get () const { return m_value; }
 164
 165  private:
 166   long m_value;
 167 };
 168
 169
 170 /* Subclass of value for strings.  */
 171
 172 class string : public value
 173 {
 174  public:
 175   explicit string (const char *utf8);
 176   string (const char *utf8, size_t len);
 177   ~string () { free (m_utf8); }
 178
 179   enum kind get_kind () const final override { return JSON_STRING; }
 180   void print (pretty_printer *pp, bool formatted) const final override;
 181
 182   const char *get_string () const { return m_utf8; }
 183   size_t get_length () const { return m_len; }
 184
 185  private:
 186   char *m_utf8;
 187   size_t m_len;
 188 };
 189
 190 /* Subclass of value for the three JSON literals "true", "false",
 191    and "null".  */
 192
 193 class literal : public value
 194 {
 195  public:
 196   literal (enum kind kind) : m_kind (kind) {}
 197
 198   /* Construct literal for a boolean value.  */
 199   literal (bool value): m_kind (value ? JSON_TRUE : JSON_FALSE) {}
 200
 201   enum kind get_kind () const final override { return m_kind; }
 202   void print (pretty_printer *pp, bool formatted) const final override;
 203
 204  private:
 205   enum kind m_kind;
 206 };
 207
 208 } // namespace json
 209
 210 #endif  /* GCC_JSON_H  */