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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
|
// Copyright (c) 2005-2022 Jay Berkenbilt
//
// This file is part of qpdf.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Versions of qpdf prior to version 7 were released under the terms
// of version 2.0 of the Artistic License. At your option, you may
// continue to consider qpdf to be licensed under those terms. Please
// see the manual for additional information.
#ifndef JSON_HH
#define JSON_HH
// This is a simple JSON serializer and parser, primarily designed for
// serializing QPDF Objects as JSON. While it may work as a
// general-purpose JSON parser/serializer, there are better options.
// JSON objects contain their data as smart pointers. When one JSON object
// is added to another, this pointer is copied. This means you can
// create temporary JSON objects on the stack, add them to other
// objects, and let them go out of scope safely. It also means that if
// a JSON object is added in more than one place, all copies
// share the underlying data. This makes them similar in structure and
// behavior to QPDFObjectHandle and may feel natural within the QPDF
// codebase, but it is also a good reason not to use this as a
// general-purpose JSON package.
#include <qpdf/DLL.h>
#include <qpdf/PointerHolder.hh>
#include <string>
#include <map>
#include <vector>
#include <list>
#include <functional>
#include <memory>
class JSON
{
public:
QPDF_DLL
std::string unparse() const;
// The JSON spec calls dictionaries "objects", but that creates
// too much confusion when referring to instances of the JSON
// class.
QPDF_DLL
static JSON makeDictionary();
// addDictionaryMember returns the newly added item.
QPDF_DLL
JSON addDictionaryMember(std::string const& key, JSON const&);
QPDF_DLL
static JSON makeArray();
// addArrayElement returns the newly added item.
QPDF_DLL
JSON addArrayElement(JSON const&);
QPDF_DLL
static JSON makeString(std::string const& utf8);
QPDF_DLL
static JSON makeInt(long long int value);
QPDF_DLL
static JSON makeReal(double value);
QPDF_DLL
static JSON makeNumber(std::string const& encoded);
QPDF_DLL
static JSON makeBool(bool value);
QPDF_DLL
static JSON makeNull();
QPDF_DLL
bool isArray() const;
QPDF_DLL
bool isDictionary() const;
// Accessors. Accessor behavior:
//
// - If argument is wrong type, including null, return false
// - If argument is right type, return true and initialize the value
QPDF_DLL
bool getString(std::string& utf8) const;
QPDF_DLL
bool getNumber(std::string& value) const;
QPDF_DLL
bool getBool(bool& value) const;
QPDF_DLL
bool isNull() const;
QPDF_DLL
bool forEachDictItem(
std::function<void(std::string const& key, JSON value)> fn) const;
QPDF_DLL
bool forEachArrayItem(std::function<void(JSON value)> fn) const;
// Check this JSON object against a "schema". This is not a schema
// according to any standard. It's just a template of what the
// JSON is supposed to contain. The checking does the following:
//
// * The schema is a nested structure containing dictionaries,
// single-element arrays, and strings only.
// * Recursively walk the schema.
// * If the current value is a dictionary, this object must have
// a dictionary in the same place with the same keys. If flags
// contains f_optional, a key in the schema does not have to
// be present in the object. Otherwise, all keys have to be
// present. Any key in the object must be present in the
// schema.
// * If the current value is an array, this object must have an
// array in the same place. The schema's array must contain a
// single element, which is used as a schema to validate each
// element of this object's corresponding array.
// * Otherwise, the value must be a string whose value is a
// description of the object's corresponding value, which may
// have any type.
//
// QPDF's JSON output conforms to certain strict compatibility
// rules as discussed in the manual. The idea is that a JSON
// structure created manually in qpdf.cc doubles as both JSON help
// information and a schema for validating the JSON that qpdf
// generates. Any discrepancies are a bug in qpdf.
//
// Flags is a bitwise or of values from check_flags_e.
enum check_flags_e {
f_none = 0,
f_optional = 1 << 0,
};
QPDF_DLL
bool checkSchema(JSON schema, unsigned long flags,
std::list<std::string>& errors);
// Same as passing 0 for flags
QPDF_DLL
bool checkSchema(JSON schema, std::list<std::string>& errors);
// Create a JSON object from a string.
QPDF_DLL
static JSON parse(std::string const&);
private:
static std::string encode_string(std::string const& utf8);
struct JSON_value
{
virtual ~JSON_value();
virtual std::string unparse(size_t depth) const = 0;
};
struct JSON_dictionary: public JSON_value
{
virtual ~JSON_dictionary();
virtual std::string unparse(size_t depth) const;
std::map<std::string, std::shared_ptr<JSON_value>> members;
};
struct JSON_array: public JSON_value
{
virtual ~JSON_array();
virtual std::string unparse(size_t depth) const;
std::vector<std::shared_ptr<JSON_value>> elements;
};
struct JSON_string: public JSON_value
{
JSON_string(std::string const& utf8);
virtual ~JSON_string();
virtual std::string unparse(size_t depth) const;
std::string utf8;
std::string encoded;
};
struct JSON_number: public JSON_value
{
JSON_number(long long val);
JSON_number(double val);
JSON_number(std::string const& val);
virtual ~JSON_number();
virtual std::string unparse(size_t depth) const;
std::string encoded;
};
struct JSON_bool: public JSON_value
{
JSON_bool(bool val);
virtual ~JSON_bool();
virtual std::string unparse(size_t depth) const;
bool value;
};
struct JSON_null: public JSON_value
{
virtual ~JSON_null();
virtual std::string unparse(size_t depth) const;
};
JSON(std::shared_ptr<JSON_value>);
static bool
checkSchemaInternal(JSON_value* this_v, JSON_value* sch_v,
unsigned long flags,
std::list<std::string>& errors,
std::string prefix);
class Members
{
friend class JSON;
public:
QPDF_DLL
~Members();
private:
Members(std::shared_ptr<JSON_value>);
Members(Members const&);
std::shared_ptr<JSON_value> value;
};
PointerHolder<Members> m;
};
#endif // JSON_HH
|
