summaryrefslogtreecommitdiff
path: root/src/json/json.c
blob: 50370296216bf2d0030946b02e76fc3b2a158a52 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/*
   This file is part of GNUnet
   Copyright (C) 2014-2017 GNUnet e.V.

   GNUnet is free software: you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.

   GNUnet is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file json/json.c
 * @brief functions to parse JSON snippets
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_json_lib.h"


/**
 * Navigate and parse data in a JSON tree.  Tries to parse the @a root
 * to find all of the values given in the @a spec.  If one of the
 * entries in @a spec cannot be found or parsed, the name of the JSON
 * field is returned in @a error_json_name, and the offset of the
 * entry in @a spec is returned in @a error_line.
 *
 * @param root the JSON node to start the navigation at.
 * @param spec parse specification array
 * @param[out] error_json_name which JSON field was problematic
 * @param[out] which index into @a spec did we encounter an error
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
 */
enum GNUNET_GenericReturnValue
GNUNET_JSON_parse (const json_t *root,
                   struct GNUNET_JSON_Specification *spec,
                   const char **error_json_name,
                   unsigned int *error_line)
{
  if (NULL == root)
    return GNUNET_SYSERR;
  for (unsigned int i = 0; NULL != spec[i].parser; i++)
  {
    json_t *pos;

    if (NULL == spec[i].field)
      pos = (json_t *) root;
    else
      pos = json_object_get (root,
                             spec[i].field);
    if ( ( (NULL == pos) ||
           (json_is_null (pos) ) ) &&
         (spec[i].is_optional) )
      continue;
    if ( (NULL == pos) ||
         (GNUNET_OK !=
          spec[i].parser (spec[i].cls,
                          pos,
                          &spec[i])) )
    {
      if (NULL != error_json_name)
        *error_json_name = spec[i].field;
      if (NULL != error_line)
        *error_line = i;
      GNUNET_JSON_parse_free (spec);
      return GNUNET_SYSERR;
    }
  }
  return GNUNET_OK; /* all OK! */
}


/**
 * Set the "optional" flag for a parser specification entry.
 *
 * @param spec specification to modify
 * @return spec copy of @a spec with optional bit set
 */
struct GNUNET_JSON_Specification
GNUNET_JSON_spec_mark_optional (struct GNUNET_JSON_Specification spec)
{
  struct GNUNET_JSON_Specification ret = spec;

  ret.is_optional = GNUNET_YES;
  return ret;
}


/**
 * Frees all elements allocated during a #GNUNET_JSON_parse()
 * operation.
 *
 * @param spec specification of the parse operation
 */
void
GNUNET_JSON_parse_free (struct GNUNET_JSON_Specification *spec)
{
  for (unsigned int i = 0; NULL != spec[i].parser; i++)
    if (NULL != spec[i].cleaner)
      spec[i].cleaner (spec[i].cls, &spec[i]);
}


/**
 * Set an option with a JSON value from the command line.
 * A pointer to this function should be passed as part of the
 * 'struct GNUNET_GETOPT_CommandLineOption' array to initialize options
 * of this type.
 *
 * @param ctx command line processing context
 * @param scls additional closure (will point to the 'json_t *')
 * @param option name of the option
 * @param value actual value of the option as a string.
 * @return #GNUNET_OK if parsing the value worked
 */
static int
set_json (struct GNUNET_GETOPT_CommandLineProcessorContext *ctx,
          void *scls,
          const char *option,
          const char *value)
{
  json_t **json = scls;
  json_error_t error;

  *json = json_loads (value, JSON_REJECT_DUPLICATES, &error);
  if (NULL == *json)
  {
    fprintf (stderr,
             _ ("Failed to parse JSON in option `%s': %s (%s)\n"),
             option,
             error.text,
             error.source);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Allow user to specify a JSON input value.
 *
 * @param shortName short name of the option
 * @param name long name of the option
 * @param argumentHelp help text for the option argument
 * @param description long help text for the option
 * @param[out] val set to the JSON specified at the command line
 */
struct GNUNET_GETOPT_CommandLineOption
GNUNET_JSON_getopt (char shortName,
                    const char *name,
                    const char *argumentHelp,
                    const char *description,
                    json_t **json)
{
  struct GNUNET_GETOPT_CommandLineOption clo = { .shortName = shortName,
                                                 .name = name,
                                                 .argumentHelp = argumentHelp,
                                                 .description = description,
                                                 .require_argument = 1,
                                                 .processor = &set_json,
                                                 .scls = (void *) json };

  return clo;
}


/* end of json.c */