1 #pragma once
2 
3 #include <exception> // exception
4 #include <stdexcept> // runtime_error
5 #include <string> // to_string
6 
7 namespace nlohmann
8 {
9 namespace detail
10 {
11 ////////////////
12 // exceptions //
13 ////////////////
14 
15 /*!
16 @brief general exception of the @ref basic_json class
17 
18 This class is an extension of `std::exception` objects with a member @a id for
19 exception ids. It is used as the base class for all exceptions thrown by the
20 @ref basic_json class. This class can hence be used as "wildcard" to catch
21 exceptions.
22 
23 Subclasses:
24 - @ref parse_error for exceptions indicating a parse error
25 - @ref invalid_iterator for exceptions indicating errors with iterators
26 - @ref type_error for exceptions indicating executing a member function with
27                   a wrong type
28 - @ref out_of_range for exceptions indicating access out of the defined range
29 - @ref other_error for exceptions indicating other library errors
30 
31 @internal
32 @note To have nothrow-copy-constructible exceptions, we internally use
33       `std::runtime_error` which can cope with arbitrary-length error messages.
34       Intermediate strings are built with static functions and then passed to
35       the actual constructor.
36 @endinternal
37 
38 @liveexample{The following code shows how arbitrary library exceptions can be
39 caught.,exception}
40 
41 @since version 3.0.0
42 */
43 class exception : public std::exception
44 {
45   public:
46     /// returns the explanatory string
what() const47     const char* what() const noexcept override
48     {
49         return m.what();
50     }
51 
52     /// the id of the exception
53     const int id;
54 
55   protected:
exception(int id_,const char * what_arg)56     exception(int id_, const char* what_arg) : id(id_), m(what_arg) {}
57 
name(const std::string & ename,int id_)58     static std::string name(const std::string& ename, int id_)
59     {
60         return "[json.exception." + ename + "." + std::to_string(id_) + "] ";
61     }
62 
63   private:
64     /// an exception object as storage for error messages
65     std::runtime_error m;
66 };
67 
68 /*!
69 @brief exception indicating a parse error
70 
71 This exception is thrown by the library when a parse error occurs. Parse errors
72 can occur during the deserialization of JSON text, CBOR, MessagePack, as well
73 as when using JSON Patch.
74 
75 Member @a byte holds the byte index of the last read character in the input
76 file.
77 
78 Exceptions have ids 1xx.
79 
80 name / id                      | example message | description
81 ------------------------------ | --------------- | -------------------------
82 json.exception.parse_error.101 | parse error at 2: unexpected end of input; expected string literal | This error indicates a syntax error while deserializing a JSON text. The error message describes that an unexpected token (character) was encountered, and the member @a byte indicates the error position.
83 json.exception.parse_error.102 | parse error at 14: missing or wrong low surrogate | JSON uses the `\uxxxx` format to describe Unicode characters. Code points above above 0xFFFF are split into two `\uxxxx` entries ("surrogate pairs"). This error indicates that the surrogate pair is incomplete or contains an invalid code point.
84 json.exception.parse_error.103 | parse error: code points above 0x10FFFF are invalid | Unicode supports code points up to 0x10FFFF. Code points above 0x10FFFF are invalid.
85 json.exception.parse_error.104 | parse error: JSON patch must be an array of objects | [RFC 6902](https://tools.ietf.org/html/rfc6902) requires a JSON Patch document to be a JSON document that represents an array of objects.
86 json.exception.parse_error.105 | parse error: operation must have string member 'op' | An operation of a JSON Patch document must contain exactly one "op" member, whose value indicates the operation to perform. Its value must be one of "add", "remove", "replace", "move", "copy", or "test"; other values are errors.
87 json.exception.parse_error.106 | parse error: array index '01' must not begin with '0' | An array index in a JSON Pointer ([RFC 6901](https://tools.ietf.org/html/rfc6901)) may be `0` or any number without a leading `0`.
88 json.exception.parse_error.107 | parse error: JSON pointer must be empty or begin with '/' - was: 'foo' | A JSON Pointer must be a Unicode string containing a sequence of zero or more reference tokens, each prefixed by a `/` character.
89 json.exception.parse_error.108 | parse error: escape character '~' must be followed with '0' or '1' | In a JSON Pointer, only `~0` and `~1` are valid escape sequences.
90 json.exception.parse_error.109 | parse error: array index 'one' is not a number | A JSON Pointer array index must be a number.
91 json.exception.parse_error.110 | parse error at 1: cannot read 2 bytes from vector | When parsing CBOR or MessagePack, the byte vector ends before the complete value has been read.
92 json.exception.parse_error.112 | parse error at 1: error reading CBOR; last byte: 0xF8 | Not all types of CBOR or MessagePack are supported. This exception occurs if an unsupported byte was read.
93 json.exception.parse_error.113 | parse error at 2: expected a CBOR string; last byte: 0x98 | While parsing a map key, a value that is not a string has been read.
94 
95 @note For an input with n bytes, 1 is the index of the first character and n+1
96       is the index of the terminating null byte or the end of file. This also
97       holds true when reading a byte vector (CBOR or MessagePack).
98 
99 @liveexample{The following code shows how a `parse_error` exception can be
100 caught.,parse_error}
101 
102 @sa @ref exception for the base class of the library exceptions
103 @sa @ref invalid_iterator for exceptions indicating errors with iterators
104 @sa @ref type_error for exceptions indicating executing a member function with
105                     a wrong type
106 @sa @ref out_of_range for exceptions indicating access out of the defined range
107 @sa @ref other_error for exceptions indicating other library errors
108 
109 @since version 3.0.0
110 */
111 class parse_error : public exception
112 {
113   public:
114     /*!
115     @brief create a parse error exception
116     @param[in] id_       the id of the exception
117     @param[in] byte_     the byte index where the error occurred (or 0 if the
118                          position cannot be determined)
119     @param[in] what_arg  the explanatory string
120     @return parse_error object
121     */
create(int id_,std::size_t byte_,const std::string & what_arg)122     static parse_error create(int id_, std::size_t byte_, const std::string& what_arg)
123     {
124         std::string w = exception::name("parse_error", id_) + "parse error" +
125                         (byte_ != 0 ? (" at " + std::to_string(byte_)) : "") +
126                         ": " + what_arg;
127         return parse_error(id_, byte_, w.c_str());
128     }
129 
130     /*!
131     @brief byte index of the parse error
132 
133     The byte index of the last read character in the input file.
134 
135     @note For an input with n bytes, 1 is the index of the first character and
136           n+1 is the index of the terminating null byte or the end of file.
137           This also holds true when reading a byte vector (CBOR or MessagePack).
138     */
139     const std::size_t byte;
140 
141   private:
parse_error(int id_,std::size_t byte_,const char * what_arg)142     parse_error(int id_, std::size_t byte_, const char* what_arg)
143         : exception(id_, what_arg), byte(byte_) {}
144 };
145 
146 /*!
147 @brief exception indicating errors with iterators
148 
149 This exception is thrown if iterators passed to a library function do not match
150 the expected semantics.
151 
152 Exceptions have ids 2xx.
153 
154 name / id                           | example message | description
155 ----------------------------------- | --------------- | -------------------------
156 json.exception.invalid_iterator.201 | iterators are not compatible | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
157 json.exception.invalid_iterator.202 | iterator does not fit current value | In an erase or insert function, the passed iterator @a pos does not belong to the JSON value for which the function was called. It hence does not define a valid position for the deletion/insertion.
158 json.exception.invalid_iterator.203 | iterators do not fit current value | Either iterator passed to function @ref erase(IteratorType first, IteratorType last) does not belong to the JSON value from which values shall be erased. It hence does not define a valid range to delete values from.
159 json.exception.invalid_iterator.204 | iterators out of range | When an iterator range for a primitive type (number, boolean, or string) is passed to a constructor or an erase function, this range has to be exactly (@ref begin(), @ref end()), because this is the only way the single stored value is expressed. All other ranges are invalid.
160 json.exception.invalid_iterator.205 | iterator out of range | When an iterator for a primitive type (number, boolean, or string) is passed to an erase function, the iterator has to be the @ref begin() iterator, because it is the only way to address the stored value. All other iterators are invalid.
161 json.exception.invalid_iterator.206 | cannot construct with iterators from null | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) belong to a JSON null value and hence to not define a valid range.
162 json.exception.invalid_iterator.207 | cannot use key() for non-object iterators | The key() member function can only be used on iterators belonging to a JSON object, because other types do not have a concept of a key.
163 json.exception.invalid_iterator.208 | cannot use operator[] for object iterators | The operator[] to specify a concrete offset cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
164 json.exception.invalid_iterator.209 | cannot use offsets with object iterators | The offset operators (+, -, +=, -=) cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
165 json.exception.invalid_iterator.210 | iterators do not fit | The iterator range passed to the insert function are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
166 json.exception.invalid_iterator.211 | passed iterators may not belong to container | The iterator range passed to the insert function must not be a subrange of the container to insert to.
167 json.exception.invalid_iterator.212 | cannot compare iterators of different containers | When two iterators are compared, they must belong to the same container.
168 json.exception.invalid_iterator.213 | cannot compare order of object iterators | The order of object iterators cannot be compared, because JSON objects are unordered.
169 json.exception.invalid_iterator.214 | cannot get value | Cannot get value for iterator: Either the iterator belongs to a null value or it is an iterator to a primitive type (number, boolean, or string), but the iterator is different to @ref begin().
170 
171 @liveexample{The following code shows how an `invalid_iterator` exception can be
172 caught.,invalid_iterator}
173 
174 @sa @ref exception for the base class of the library exceptions
175 @sa @ref parse_error for exceptions indicating a parse error
176 @sa @ref type_error for exceptions indicating executing a member function with
177                     a wrong type
178 @sa @ref out_of_range for exceptions indicating access out of the defined range
179 @sa @ref other_error for exceptions indicating other library errors
180 
181 @since version 3.0.0
182 */
183 class invalid_iterator : public exception
184 {
185   public:
create(int id_,const std::string & what_arg)186     static invalid_iterator create(int id_, const std::string& what_arg)
187     {
188         std::string w = exception::name("invalid_iterator", id_) + what_arg;
189         return invalid_iterator(id_, w.c_str());
190     }
191 
192   private:
invalid_iterator(int id_,const char * what_arg)193     invalid_iterator(int id_, const char* what_arg)
194         : exception(id_, what_arg) {}
195 };
196 
197 /*!
198 @brief exception indicating executing a member function with a wrong type
199 
200 This exception is thrown in case of a type error; that is, a library function is
201 executed on a JSON value whose type does not match the expected semantics.
202 
203 Exceptions have ids 3xx.
204 
205 name / id                     | example message | description
206 ----------------------------- | --------------- | -------------------------
207 json.exception.type_error.301 | cannot create object from initializer list | To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
208 json.exception.type_error.302 | type must be object, but is array | During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
209 json.exception.type_error.303 | incompatible ReferenceType for get_ref, actual type is object | To retrieve a reference to a value stored in a @ref basic_json object with @ref get_ref, the type of the reference must match the value type. For instance, for a JSON array, the @a ReferenceType must be @ref array_t&.
210 json.exception.type_error.304 | cannot use at() with string | The @ref at() member functions can only be executed for certain JSON types.
211 json.exception.type_error.305 | cannot use operator[] with string | The @ref operator[] member functions can only be executed for certain JSON types.
212 json.exception.type_error.306 | cannot use value() with string | The @ref value() member functions can only be executed for certain JSON types.
213 json.exception.type_error.307 | cannot use erase() with string | The @ref erase() member functions can only be executed for certain JSON types.
214 json.exception.type_error.308 | cannot use push_back() with string | The @ref push_back() and @ref operator+= member functions can only be executed for certain JSON types.
215 json.exception.type_error.309 | cannot use insert() with | The @ref insert() member functions can only be executed for certain JSON types.
216 json.exception.type_error.310 | cannot use swap() with number | The @ref swap() member functions can only be executed for certain JSON types.
217 json.exception.type_error.311 | cannot use emplace_back() with string | The @ref emplace_back() member function can only be executed for certain JSON types.
218 json.exception.type_error.312 | cannot use update() with string | The @ref update() member functions can only be executed for certain JSON types.
219 json.exception.type_error.313 | invalid value to unflatten | The @ref unflatten function converts an object whose keys are JSON Pointers back into an arbitrary nested JSON value. The JSON Pointers must not overlap, because then the resulting value would not be well defined.
220 json.exception.type_error.314 | only objects can be unflattened | The @ref unflatten function only works for an object whose keys are JSON Pointers.
221 json.exception.type_error.315 | values in object must be primitive | The @ref unflatten function only works for an object whose keys are JSON Pointers and whose values are primitive.
222 json.exception.type_error.316 | invalid UTF-8 byte at index 10: 0x7E | The @ref dump function only works with UTF-8 encoded strings; that is, if you assign a `std::string` to a JSON value, make sure it is UTF-8 encoded. |
223 
224 @liveexample{The following code shows how a `type_error` exception can be
225 caught.,type_error}
226 
227 @sa @ref exception for the base class of the library exceptions
228 @sa @ref parse_error for exceptions indicating a parse error
229 @sa @ref invalid_iterator for exceptions indicating errors with iterators
230 @sa @ref out_of_range for exceptions indicating access out of the defined range
231 @sa @ref other_error for exceptions indicating other library errors
232 
233 @since version 3.0.0
234 */
235 class type_error : public exception
236 {
237   public:
create(int id_,const std::string & what_arg)238     static type_error create(int id_, const std::string& what_arg)
239     {
240         std::string w = exception::name("type_error", id_) + what_arg;
241         return type_error(id_, w.c_str());
242     }
243 
244   private:
type_error(int id_,const char * what_arg)245     type_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
246 };
247 
248 /*!
249 @brief exception indicating access out of the defined range
250 
251 This exception is thrown in case a library function is called on an input
252 parameter that exceeds the expected range, for instance in case of array
253 indices or nonexisting object keys.
254 
255 Exceptions have ids 4xx.
256 
257 name / id                       | example message | description
258 ------------------------------- | --------------- | -------------------------
259 json.exception.out_of_range.401 | array index 3 is out of range | The provided array index @a i is larger than @a size-1.
260 json.exception.out_of_range.402 | array index '-' (3) is out of range | The special array index `-` in a JSON Pointer never describes a valid element of the array, but the index past the end. That is, it can only be used to add elements at this position, but not to read it.
261 json.exception.out_of_range.403 | key 'foo' not found | The provided key was not found in the JSON object.
262 json.exception.out_of_range.404 | unresolved reference token 'foo' | A reference token in a JSON Pointer could not be resolved.
263 json.exception.out_of_range.405 | JSON pointer has no parent | The JSON Patch operations 'remove' and 'add' can not be applied to the root element of the JSON value.
264 json.exception.out_of_range.406 | number overflow parsing '10E1000' | A parsed number could not be stored as without changing it to NaN or INF.
265 json.exception.out_of_range.407 | number overflow serializing '9223372036854775808' | UBJSON only supports integers numbers up to 9223372036854775807. |
266 json.exception.out_of_range.408 | excessive array size: 8658170730974374167 | The size (following `#`) of an UBJSON array or object exceeds the maximal capacity. |
267 
268 @liveexample{The following code shows how an `out_of_range` exception can be
269 caught.,out_of_range}
270 
271 @sa @ref exception for the base class of the library exceptions
272 @sa @ref parse_error for exceptions indicating a parse error
273 @sa @ref invalid_iterator for exceptions indicating errors with iterators
274 @sa @ref type_error for exceptions indicating executing a member function with
275                     a wrong type
276 @sa @ref other_error for exceptions indicating other library errors
277 
278 @since version 3.0.0
279 */
280 class out_of_range : public exception
281 {
282   public:
create(int id_,const std::string & what_arg)283     static out_of_range create(int id_, const std::string& what_arg)
284     {
285         std::string w = exception::name("out_of_range", id_) + what_arg;
286         return out_of_range(id_, w.c_str());
287     }
288 
289   private:
out_of_range(int id_,const char * what_arg)290     out_of_range(int id_, const char* what_arg) : exception(id_, what_arg) {}
291 };
292 
293 /*!
294 @brief exception indicating other library errors
295 
296 This exception is thrown in case of errors that cannot be classified with the
297 other exception types.
298 
299 Exceptions have ids 5xx.
300 
301 name / id                      | example message | description
302 ------------------------------ | --------------- | -------------------------
303 json.exception.other_error.501 | unsuccessful: {"op":"test","path":"/baz", "value":"bar"} | A JSON Patch operation 'test' failed. The unsuccessful operation is also printed.
304 
305 @sa @ref exception for the base class of the library exceptions
306 @sa @ref parse_error for exceptions indicating a parse error
307 @sa @ref invalid_iterator for exceptions indicating errors with iterators
308 @sa @ref type_error for exceptions indicating executing a member function with
309                     a wrong type
310 @sa @ref out_of_range for exceptions indicating access out of the defined range
311 
312 @liveexample{The following code shows how an `other_error` exception can be
313 caught.,other_error}
314 
315 @since version 3.0.0
316 */
317 class other_error : public exception
318 {
319   public:
create(int id_,const std::string & what_arg)320     static other_error create(int id_, const std::string& what_arg)
321     {
322         std::string w = exception::name("other_error", id_) + what_arg;
323         return other_error(id_, w.c_str());
324     }
325 
326   private:
other_error(int id_,const char * what_arg)327     other_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
328 };
329 }
330 }
331