1 //! Deserialize JSON data to a Rust data structure.
3 use crate::error
::{Error, ErrorCode, Result}
;
4 #[cfg(feature = "float_roundtrip")]
6 use crate::lib
::str::FromStr
;
8 use crate::number
::Number
;
9 use crate::read
::{self, Fused, Reference}
;
10 use serde
::de
::{self, Expected, Unexpected}
;
11 use serde
::{forward_to_deserialize_any, serde_if_integer128}
;
13 #[cfg(feature = "arbitrary_precision")]
14 use crate::number
::NumberDeserializer
;
16 pub use crate::read
::{Read, SliceRead, StrRead}
;
18 #[cfg(feature = "std")]
19 pub use crate::read
::IoRead
;
21 //////////////////////////////////////////////////////////////////////////////
23 /// A structure that deserializes JSON into Rust values.
24 pub struct Deserializer
<R
> {
28 #[cfg(feature = "float_roundtrip")]
29 single_precision
: bool
,
30 #[cfg(feature = "unbounded_depth")]
31 disable_recursion_limit
: bool
,
34 impl<'de
, R
> Deserializer
<R
>
38 /// Create a JSON deserializer from one of the possible serde_json input
41 /// Typically it is more convenient to use one of these methods instead:
43 /// - Deserializer::from_str
44 /// - Deserializer::from_bytes
45 /// - Deserializer::from_reader
46 pub fn new(read
: R
) -> Self {
51 #[cfg(feature = "float_roundtrip")]
52 single_precision
: false,
53 #[cfg(feature = "unbounded_depth")]
54 disable_recursion_limit
: false,
59 #[cfg(feature = "std")]
60 impl<R
> Deserializer
<read
::IoRead
<R
>>
64 /// Creates a JSON deserializer from an `io::Read`.
66 /// Reader-based deserializers do not support deserializing borrowed types
67 /// like `&str`, since the `std::io::Read` trait has no non-copying methods
68 /// -- everything it does involves copying bytes out of the data source.
69 pub fn from_reader(reader
: R
) -> Self {
70 Deserializer
::new(read
::IoRead
::new(reader
))
74 impl<'a
> Deserializer
<read
::SliceRead
<'a
>> {
75 /// Creates a JSON deserializer from a `&[u8]`.
76 pub fn from_slice(bytes
: &'a
[u8]) -> Self {
77 Deserializer
::new(read
::SliceRead
::new(bytes
))
81 impl<'a
> Deserializer
<read
::StrRead
<'a
>> {
82 /// Creates a JSON deserializer from a `&str`.
83 pub fn from_str(s
: &'a
str) -> Self {
84 Deserializer
::new(read
::StrRead
::new(s
))
88 macro_rules
! overflow
{
89 ($a
:ident
* 10 + $b
:ident
, $c
:expr
) => {
90 $a
>= $c
/ 10 && ($a
> $c
/ 10 || $b
> $c
% 10)
94 pub(crate) enum ParserNumber
{
98 #[cfg(feature = "arbitrary_precision")]
103 fn visit
<'de
, V
>(self, visitor
: V
) -> Result
<V
::Value
>
108 ParserNumber
::F64(x
) => visitor
.visit_f64(x
),
109 ParserNumber
::U64(x
) => visitor
.visit_u64(x
),
110 ParserNumber
::I64(x
) => visitor
.visit_i64(x
),
111 #[cfg(feature = "arbitrary_precision")]
112 ParserNumber
::String(x
) => visitor
.visit_map(NumberDeserializer { number: x.into() }
),
116 fn invalid_type(self, exp
: &dyn Expected
) -> Error
{
118 ParserNumber
::F64(x
) => de
::Error
::invalid_type(Unexpected
::Float(x
), exp
),
119 ParserNumber
::U64(x
) => de
::Error
::invalid_type(Unexpected
::Unsigned(x
), exp
),
120 ParserNumber
::I64(x
) => de
::Error
::invalid_type(Unexpected
::Signed(x
), exp
),
121 #[cfg(feature = "arbitrary_precision")]
122 ParserNumber
::String(_
) => de
::Error
::invalid_type(Unexpected
::Other("number"), exp
),
127 impl<'de
, R
: Read
<'de
>> Deserializer
<R
> {
128 /// The `Deserializer::end` method should be called after a value has been fully deserialized.
129 /// This allows the `Deserializer` to validate that the input stream is at the end or that it
130 /// only has trailing whitespace.
131 pub fn end(&mut self) -> Result
<()> {
132 match tri
!(self.parse_whitespace()) {
133 Some(_
) => Err(self.peek_error(ErrorCode
::TrailingCharacters
)),
138 /// Turn a JSON deserializer into an iterator over values of type T.
139 pub fn into_iter
<T
>(self) -> StreamDeserializer
<'de
, R
, T
>
141 T
: de
::Deserialize
<'de
>,
143 // This cannot be an implementation of std::iter::IntoIterator because
144 // we need the caller to choose what T is.
145 let offset
= self.read
.byte_offset();
151 lifetime
: PhantomData
,
155 /// Parse arbitrarily deep JSON structures without any consideration for
156 /// overflowing the stack.
158 /// You will want to provide some other way to protect against stack
159 /// overflows, such as by wrapping your Deserializer in the dynamically
160 /// growing stack adapter provided by the serde_stacker crate. Additionally
161 /// you will need to be careful around other recursive operations on the
162 /// parsed result which may overflow the stack after deserialization has
163 /// completed, including, but not limited to, Display and Debug and Drop
166 /// *This method is only available if serde_json is built with the
167 /// `"unbounded_depth"` feature.*
172 /// use serde::Deserialize;
173 /// use serde_json::Value;
176 /// let mut json = String::new();
177 /// for _ in 0..10000 {
178 /// json = format!("[{}]", json);
181 /// let mut deserializer = serde_json::Deserializer::from_str(&json);
182 /// deserializer.disable_recursion_limit();
183 /// let deserializer = serde_stacker::Deserializer::new(&mut deserializer);
184 /// let value = Value::deserialize(deserializer).unwrap();
186 /// carefully_drop_nested_arrays(value);
189 /// fn carefully_drop_nested_arrays(value: Value) {
190 /// let mut stack = vec![value];
191 /// while let Some(value) = stack.pop() {
192 /// if let Value::Array(array) = value {
193 /// stack.extend(array);
198 #[cfg(feature = "unbounded_depth")]
199 pub fn disable_recursion_limit(&mut self) {
200 self.disable_recursion_limit
= true;
203 fn peek(&mut self) -> Result
<Option
<u8>> {
207 fn peek_or_null(&mut self) -> Result
<u8> {
208 Ok(tri
!(self.peek()).unwrap_or(b'
\x00'
))
211 fn eat_char(&mut self) {
215 fn next_char(&mut self) -> Result
<Option
<u8>> {
219 fn next_char_or_null(&mut self) -> Result
<u8> {
220 Ok(tri
!(self.next_char()).unwrap_or(b'
\x00'
))
223 /// Error caused by a byte from next_char().
225 fn error(&self, reason
: ErrorCode
) -> Error
{
226 let position
= self.read
.position();
227 Error
::syntax(reason
, position
.line
, position
.column
)
230 /// Error caused by a byte from peek().
232 fn peek_error(&self, reason
: ErrorCode
) -> Error
{
233 let position
= self.read
.peek_position();
234 Error
::syntax(reason
, position
.line
, position
.column
)
237 /// Returns the first non-whitespace byte without consuming it, or `None` if
238 /// EOF is encountered.
239 fn parse_whitespace(&mut self) -> Result
<Option
<u8>> {
241 match tri
!(self.peek()) {
242 Some(b' '
) | Some(b'
\n'
) | Some(b'
\t'
) | Some(b'
\r'
) => {
253 fn peek_invalid_type(&mut self, exp
: &dyn Expected
) -> Error
{
254 let err
= match self.peek_or_null().unwrap_or(b'
\x00'
) {
257 if let Err(err
) = self.parse_ident(b
"ull") {
260 de
::Error
::invalid_type(Unexpected
::Unit
, exp
)
264 if let Err(err
) = self.parse_ident(b
"rue") {
267 de
::Error
::invalid_type(Unexpected
::Bool(true), exp
)
271 if let Err(err
) = self.parse_ident(b
"alse") {
274 de
::Error
::invalid_type(Unexpected
::Bool(false), exp
)
278 match self.parse_any_number(false) {
279 Ok(n
) => n
.invalid_type(exp
),
280 Err(err
) => return err
,
283 b'
0'
..=b'
9'
=> match self.parse_any_number(true) {
284 Ok(n
) => n
.invalid_type(exp
),
285 Err(err
) => return err
,
289 self.scratch.clear();
290 match self.read.parse_str(&mut self.scratch) {
291 Ok(s) => de::Error::invalid_type(Unexpected::Str(&s), exp),
292 Err(err) => return err,
295 b'[' => de::Error::invalid_type(Unexpected::Seq, exp),
296 b'{' => de::Error::invalid_type(Unexpected::Map, exp),
297 _ => self.peek_error(ErrorCode::ExpectedSomeValue),
300 self.fix_position(err)
303 fn deserialize_number<V>(&mut self, visitor: V) -> Result<V::Value>
307 let peek = match tri!(self.parse_whitespace()) {
310 return Err(self.peek_error(ErrorCode::EofWhileParsingValue));
314 let value = match peek {
317 tri!(self.parse_integer(false)).visit(visitor)
319 b'0'..=b'9' => tri!(self.parse_integer(true)).visit(visitor),
320 _ => Err(self.peek_invalid_type(&visitor)),
324 Ok(value) => Ok(value),
325 Err(err) => Err(self.fix_position(err)),
329 serde_if_integer128! {
330 fn scan_integer128(&mut self, buf: &mut String) -> Result<()> {
331 match tri!(self.next_char_or_null()) {
334 // There can be only one leading '0'.
335 match tri!(self.peek_or_null()) {
337 Err(self.peek_error(ErrorCode::InvalidNumber))
344 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
351 Err(self.error(ErrorCode::InvalidNumber))
358 fn fix_position(&self, err: Error) -> Error {
359 err.fix_position(move |code| self.error(code))
362 fn parse_ident(&mut self, ident: &[u8]) -> Result<()> {
363 for expected in ident {
364 match tri!(self.next_char()) {
366 return Err(self.error(ErrorCode::EofWhileParsingValue));
369 if next != *expected {
370 return Err(self.error(ErrorCode::ExpectedSomeIdent));
379 fn parse_integer(&mut self, positive: bool) -> Result<ParserNumber> {
380 let next = match tri!(self.next_char()) {
383 return Err(self.error(ErrorCode::EofWhileParsingValue));
389 // There can be only one leading '0'.
390 match tri!(self.peek_or_null()) {
391 b'0'..=b'9' => Err(self.peek_error(ErrorCode::InvalidNumber)),
392 _ => self.parse_number(positive, 0),
396 let mut significand = (c - b'0') as u64;
399 match tri!(self.peek_or_null()) {
401 let digit = (c - b'0') as u64;
403 // We need to be careful with overflow. If we can,
404 // try to keep the number as a `u64` until we grow
405 // too large. At that point, switch to parsing the
407 if overflow!(significand * 10 + digit, u64::max_value()) {
408 return Ok(ParserNumber::F64(tri!(
409 self.parse_long_integer(positive, significand),
414 significand = significand * 10 + digit;
417 return self.parse_number(positive, significand);
422 _ => Err(self.error(ErrorCode::InvalidNumber)),
426 fn parse_number(&mut self, positive: bool, significand: u64) -> Result<ParserNumber> {
427 Ok(match tri!(self.peek_or_null()) {
428 b'.' => ParserNumber::F64(tri!(self.parse_decimal(positive, significand, 0))),
429 b'e' | b'E' => ParserNumber::F64(tri!(self.parse_exponent(positive, significand, 0))),
432 ParserNumber::U64(significand)
434 let neg = (significand as i64).wrapping_neg();
436 // Convert into a float if we underflow.
438 ParserNumber::F64(-(significand as f64))
440 ParserNumber::I64(neg)
450 mut significand: u64,
455 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
456 let digit = (c - b'0') as u64;
458 if overflow!(significand * 10 + digit, u64::max_value()) {
459 return self.parse_decimal_overflow(positive, significand, exponent);
463 significand = significand * 10 + digit;
467 // Error if there is not at least one digit after the decimal point.
469 match tri!(self.peek()) {
470 Some(_) => return Err(self.peek_error(ErrorCode::InvalidNumber)),
471 None => return Err(self.peek_error(ErrorCode::EofWhileParsingValue)),
475 match tri!(self.peek_or_null()) {
476 b'e' | b'E' => self.parse_exponent(positive, significand, exponent),
477 _ => self.f64_from_parts(positive, significand, exponent),
489 let positive_exp = match tri!(self.peek_or_null()) {
501 let next = match tri!(self.next_char()) {
504 return Err(self.error(ErrorCode::EofWhileParsingValue));
508 // Make sure a digit follows the exponent place.
509 let mut exp = match next {
510 c @ b'0'..=b'9' => (c - b'0') as i32,
512 return Err(self.error(ErrorCode::InvalidNumber));
516 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
518 let digit = (c - b'0') as i32;
520 if overflow!(exp * 10 + digit, i32::max_value()) {
521 let zero_significand = significand == 0;
522 return self.parse_exponent_overflow(positive, zero_significand, positive_exp);
525 exp = exp * 10 + digit;
528 let final_exp = if positive_exp {
529 starting_exp.saturating_add(exp)
531 starting_exp.saturating_sub(exp)
534 self.f64_from_parts(positive, significand, final_exp)
537 #[cfg(feature = "float_roundtrip
")]
538 fn f64_from_parts(&mut self, positive: bool, significand: u64, exponent: i32) -> Result<f64> {
539 let f = if self.single_precision {
540 lexical::parse_concise_float::<f32>(significand, exponent) as f64
542 lexical::parse_concise_float::<f64>(significand, exponent)
546 Err(self.error(ErrorCode::NumberOutOfRange))
548 Ok(if positive { f } else { -f })
552 #[cfg(not(feature = "float_roundtrip
"))]
559 let mut f = significand as f64;
561 match POW10.get(exponent.wrapping_abs() as usize) {
566 return Err(self.error(ErrorCode::NumberOutOfRange));
578 return Err(self.error(ErrorCode::NumberOutOfRange));
585 Ok(if positive { f } else { -f })
588 #[cfg(feature = "float_roundtrip
")]
591 fn parse_long_integer(&mut self, positive: bool, partial_significand: u64) -> Result<f64> {
592 // To deserialize floats we'll first push the integer and fraction
593 // parts, both as byte strings, into the scratch buffer and then feed
594 // both slices to lexical's parser. For example if the input is
595 // `12.34e5` we'll push b"1234" into scratch and then pass b"12" and
596 // b"34" to lexical. `integer_end` will be used to track where to split
597 // the scratch buffer.
599 // Note that lexical expects the integer part to contain *no* leading
600 // zeroes and the fraction part to contain *no* trailing zeroes. The
601 // first requirement is already handled by the integer parsing logic.
602 // The second requirement will be enforced just before passing the
603 // slices to lexical in f64_long_from_parts.
604 self.scratch.clear();
606 .extend_from_slice(itoa::Buffer::new().format(partial_significand).as_bytes());
609 match tri!(self.peek_or_null()) {
611 self.scratch.push(c);
616 return self.parse_long_decimal(positive, self.scratch.len());
619 return self.parse_long_exponent(positive, self.scratch.len());
622 return self.f64_long_from_parts(positive, self.scratch.len(), 0);
628 #[cfg(not(feature = "float_roundtrip
"))]
631 fn parse_long_integer(&mut self, positive: bool, significand: u64) -> Result<f64> {
632 let mut exponent = 0;
634 match tri!(self.peek_or_null()) {
637 // This could overflow... if your integer is gigabytes long.
638 // Ignore that possibility.
642 return self.parse_decimal(positive, significand, exponent);
645 return self.parse_exponent(positive, significand, exponent);
648 return self.f64_from_parts(positive, significand, exponent);
654 #[cfg(feature = "float_roundtrip
")]
656 fn parse_long_decimal(&mut self, positive: bool, integer_end: usize) -> Result<f64> {
657 let mut at_least_one_digit = integer_end < self.scratch.len();
658 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
659 self.scratch.push(c);
661 at_least_one_digit = true;
664 if !at_least_one_digit {
665 match tri!(self.peek()) {
666 Some(_) => return Err(self.peek_error(ErrorCode::InvalidNumber)),
667 None => return Err(self.peek_error(ErrorCode::EofWhileParsingValue)),
671 match tri!(self.peek_or_null()) {
672 b'e' | b'E' => self.parse_long_exponent(positive, integer_end),
673 _ => self.f64_long_from_parts(positive, integer_end, 0),
677 #[cfg(feature = "float_roundtrip
")]
678 fn parse_long_exponent(&mut self, positive: bool, integer_end: usize) -> Result<f64> {
681 let positive_exp = match tri!(self.peek_or_null()) {
693 let next = match tri!(self.next_char()) {
696 return Err(self.error(ErrorCode::EofWhileParsingValue));
700 // Make sure a digit follows the exponent place.
701 let mut exp = match next {
702 c @ b'0'..=b'9' => (c - b'0') as i32,
704 return Err(self.error(ErrorCode::InvalidNumber));
708 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
710 let digit = (c - b'0') as i32;
712 if overflow!(exp * 10 + digit, i32::max_value()) {
713 let zero_significand = self.scratch.iter().all(|&digit| digit == b'0');
714 return self.parse_exponent_overflow(positive, zero_significand, positive_exp);
717 exp = exp * 10 + digit;
720 let final_exp = if positive_exp { exp } else { -exp };
722 self.f64_long_from_parts(positive, integer_end, final_exp)
725 // This cold code should not be inlined into the middle of the hot
726 // decimal-parsing loop above.
727 #[cfg(feature = "float_roundtrip
")]
730 fn parse_decimal_overflow(
736 let mut buffer = itoa::Buffer::new();
737 let significand = buffer.format(significand);
738 let fraction_digits = -exponent as usize;
739 self.scratch.clear();
740 if let Some(zeros) = fraction_digits.checked_sub(significand.len() + 1) {
741 self.scratch.extend(iter::repeat(b'0').take(zeros + 1));
743 self.scratch.extend_from_slice(significand.as_bytes());
744 let integer_end = self.scratch.len() - fraction_digits;
745 self.parse_long_decimal(positive, integer_end)
748 #[cfg(not(feature = "float_roundtrip
"))]
751 fn parse_decimal_overflow(
757 // The next multiply/add would overflow, so just ignore all further
759 while let b'0'..=b'9' = tri!(self.peek_or_null()) {
763 match tri!(self.peek_or_null()) {
764 b'e' | b'E' => self.parse_exponent(positive, significand, exponent),
765 _ => self.f64_from_parts(positive, significand, exponent),
769 // This cold code should not be inlined into the middle of the hot
770 // exponent-parsing loop above.
773 fn parse_exponent_overflow(
776 zero_significand: bool,
779 // Error instead of +/- infinity.
780 if !zero_significand && positive_exp {
781 return Err(self.error(ErrorCode::NumberOutOfRange));
784 while let b'0'..=b'9' = tri!(self.peek_or_null()) {
787 Ok(if positive { 0.0 } else { -0.0 })
790 #[cfg(feature = "float_roundtrip
")]
791 fn f64_long_from_parts(
797 let integer = &self.scratch[..integer_end];
798 let fraction = &self.scratch[integer_end..];
800 let f = if self.single_precision {
801 lexical::parse_truncated_float::<f32>(integer, fraction, exponent) as f64
803 lexical::parse_truncated_float::<f64>(integer, fraction, exponent)
807 Err(self.error(ErrorCode::NumberOutOfRange))
809 Ok(if positive { f } else { -f })
813 fn parse_any_signed_number(&mut self) -> Result<ParserNumber> {
814 let peek = match tri!(self.peek()) {
817 return Err(self.peek_error(ErrorCode::EofWhileParsingValue));
821 let value = match peek {
824 self.parse_any_number(false)
826 b'0'..=b'9' => self.parse_any_number(true),
827 _ => Err(self.peek_error(ErrorCode::InvalidNumber)),
830 let value = match tri!(self.peek()) {
831 Some(_) => Err(self.peek_error(ErrorCode::InvalidNumber)),
836 Ok(value) => Ok(value),
837 // The de::Error impl creates errors with unknown line and column.
838 // Fill in the position here by looking at the current index in the
839 // input. There is no way to tell whether this should call `error`
840 // or `peek_error` so pick the one that seems correct more often.
841 // Worst case, the position is off by one character.
842 Err(err) => Err(self.fix_position(err)),
846 #[cfg(not(feature = "arbitrary_precision
"))]
847 fn parse_any_number(&mut self, positive: bool) -> Result<ParserNumber> {
848 self.parse_integer(positive)
851 #[cfg(feature = "arbitrary_precision
")]
852 fn parse_any_number(&mut self, positive: bool) -> Result<ParserNumber> {
853 let mut buf = String::with_capacity(16);
857 self.scan_integer(&mut buf)?;
858 Ok(ParserNumber::String(buf))
861 #[cfg(feature = "arbitrary_precision
")]
862 fn scan_or_eof(&mut self, buf: &mut String) -> Result<u8> {
863 match tri!(self.next_char()) {
868 None => Err(self.error(ErrorCode::EofWhileParsingValue)),
872 #[cfg(feature = "arbitrary_precision
")]
873 fn scan_integer(&mut self, buf: &mut String) -> Result<()> {
874 match tri!(self.scan_or_eof(buf)) {
876 // There can be only one leading '0'.
877 match tri!(self.peek_or_null()) {
878 b'0'..=b'9' => Err(self.peek_error(ErrorCode::InvalidNumber)),
879 _ => self.scan_number(buf),
882 b'1'..=b'9' => loop {
883 match tri!(self.peek_or_null()) {
889 return self.scan_number(buf);
893 _ => Err(self.error(ErrorCode::InvalidNumber)),
897 #[cfg(feature = "arbitrary_precision
")]
898 fn scan_number(&mut self, buf: &mut String) -> Result<()> {
899 match tri!(self.peek_or_null()) {
900 b'.' => self.scan_decimal(buf),
901 b'e' | b'E' => self.scan_exponent(buf),
906 #[cfg(feature = "arbitrary_precision
")]
907 fn scan_decimal(&mut self, buf: &mut String) -> Result<()> {
911 let mut at_least_one_digit = false;
912 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
915 at_least_one_digit = true;
918 if !at_least_one_digit {
919 match tri!(self.peek()) {
920 Some(_) => return Err(self.peek_error(ErrorCode::InvalidNumber)),
921 None => return Err(self.peek_error(ErrorCode::EofWhileParsingValue)),
925 match tri!(self.peek_or_null()) {
926 b'e' | b'E' => self.scan_exponent(buf),
931 #[cfg(feature = "arbitrary_precision
")]
932 fn scan_exponent(&mut self, buf: &mut String) -> Result<()> {
936 match tri!(self.peek_or_null()) {
947 // Make sure a digit follows the exponent place.
948 match tri!(self.scan_or_eof(buf)) {
951 return Err(self.error(ErrorCode::InvalidNumber));
955 while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) {
963 fn parse_object_colon(&mut self) -> Result<()> {
964 match tri!(self.parse_whitespace()) {
969 Some(_) => Err(self.peek_error(ErrorCode::ExpectedColon)),
970 None => Err(self.peek_error(ErrorCode::EofWhileParsingObject)),
974 fn end_seq(&mut self) -> Result<()> {
975 match tri!(self.parse_whitespace()) {
982 match self.parse_whitespace() {
983 Ok(Some(b']')) => Err(self.peek_error(ErrorCode::TrailingComma)),
984 _ => Err(self.peek_error(ErrorCode::TrailingCharacters)),
987 Some(_) => Err(self.peek_error(ErrorCode::TrailingCharacters)),
988 None => Err(self.peek_error(ErrorCode::EofWhileParsingList)),
992 fn end_map(&mut self) -> Result<()> {
993 match tri!(self.parse_whitespace()) {
998 Some(b',') => Err(self.peek_error(ErrorCode::TrailingComma)),
999 Some(_) => Err(self.peek_error(ErrorCode::TrailingCharacters)),
1000 None => Err(self.peek_error(ErrorCode::EofWhileParsingObject)),
1004 fn ignore_value(&mut self) -> Result<()> {
1005 self.scratch.clear();
1006 let mut enclosing = None;
1009 let peek = match tri!(self.parse_whitespace()) {
1012 return Err(self.peek_error(ErrorCode::EofWhileParsingValue));
1016 let frame = match peek {
1019 tri!(self.parse_ident(b"ull
"));
1024 tri!(self.parse_ident(b"rue
"));
1029 tri!(self.parse_ident(b"alse
"));
1034 tri!(self.ignore_integer());
1038 tri!(self.ignore_integer());
1043 tri
!(self.read
.ignore_str());
1046 frame @ b'
['
| frame @ b'
{'
=> {
1047 self.scratch
.extend(enclosing
.take());
1051 _
=> return Err(self.peek_error(ErrorCode
::ExpectedSomeValue
)),
1054 let (mut accept_comma
, mut frame
) = match frame
{
1055 Some(frame
) => (false, frame
),
1056 None
=> match enclosing
.take() {
1057 Some(frame
) => (true, frame
),
1058 None
=> match self.scratch
.pop() {
1059 Some(frame
) => (true, frame
),
1060 None
=> return Ok(()),
1066 match tri
!(self.parse_whitespace()) {
1067 Some(b'
,'
) if accept_comma
=> {
1071 Some(b'
]'
) if frame
== b'
['
=> {}
1072 Some(b'
}'
) if frame
== b'{' => {}
1075 return Err(self.peek_error(match frame
{
1076 b'
['
=> ErrorCode
::ExpectedListCommaOrEnd
,
1077 b'
{'
=> ErrorCode
::ExpectedObjectCommaOrEnd
,
1078 _
=> unreachable
!(),
1085 return Err(self.peek_error(match frame
{
1086 b'
['
=> ErrorCode
::EofWhileParsingList
,
1087 b'
{'
=> ErrorCode
::EofWhileParsingObject
,
1088 _
=> unreachable
!(),
1094 frame
= match self.scratch
.pop() {
1095 Some(frame
) => frame
,
1096 None
=> return Ok(()),
1098 accept_comma
= true;
1102 match tri
!(self.parse_whitespace()) {
1103 Some(b'
"') => self.eat_char(),
1104 Some(_) => return Err(self.peek_error(ErrorCode::KeyMustBeAString)),
1105 None => return Err(self.peek_error(ErrorCode::EofWhileParsingObject)),
1107 tri!(self.read.ignore_str());
1108 match tri!(self.parse_whitespace()) {
1109 Some(b':') => self.eat_char(),
1110 Some(_) => return Err(self.peek_error(ErrorCode::ExpectedColon)),
1111 None => return Err(self.peek_error(ErrorCode::EofWhileParsingObject)),
1115 enclosing = Some(frame);
1119 fn ignore_integer(&mut self) -> Result<()> {
1120 match tri!(self.next_char_or_null()) {
1122 // There can be only one leading '0'.
1123 if let b'0'..=b'9' = tri!(self.peek_or_null()) {
1124 return Err(self.peek_error(ErrorCode::InvalidNumber));
1128 while let b'0'..=b'9' = tri!(self.peek_or_null()) {
1133 return Err(self.error(ErrorCode::InvalidNumber));
1137 match tri!(self.peek_or_null()) {
1138 b'.' => self.ignore_decimal(),
1139 b'e' | b'E' => self.ignore_exponent(),
1144 fn ignore_decimal(&mut self) -> Result<()> {
1147 let mut at_least_one_digit = false;
1148 while let b'0'..=b'9' = tri!(self.peek_or_null()) {
1150 at_least_one_digit = true;
1153 if !at_least_one_digit {
1154 return Err(self.peek_error(ErrorCode::InvalidNumber));
1157 match tri!(self.peek_or_null()) {
1158 b'e' | b'E' => self.ignore_exponent(),
1163 fn ignore_exponent(&mut self) -> Result<()> {
1166 match tri!(self.peek_or_null()) {
1167 b'+' | b'-' => self.eat_char(),
1171 // Make sure a digit follows the exponent place.
1172 match tri!(self.next_char_or_null()) {
1175 return Err(self.error(ErrorCode::InvalidNumber));
1179 while let b'0'..=b'9' = tri!(self.peek_or_null()) {
1186 #[cfg(feature = "raw_value
")]
1187 fn deserialize_raw_value<V>(&mut self, visitor: V) -> Result<V::Value>
1189 V: de::Visitor<'de>,
1191 self.parse_whitespace()?;
1192 self.read.begin_raw_buffering();
1193 self.ignore_value()?;
1194 self.read.end_raw_buffering(visitor)
1198 impl FromStr for Number {
1201 fn from_str(s: &str) -> result::Result<Self, Self::Err> {
1202 Deserializer::from_str(s)
1203 .parse_any_signed_number()
1208 #[cfg(not(feature = "float_roundtrip
"))]
1209 static POW10: [f64; 309] = [
1210 1e000, 1e001, 1e002, 1e003, 1e004, 1e005, 1e006, 1e007, 1e008, 1e009, //
1211 1e010, 1e011, 1e012, 1e013, 1e014, 1e015, 1e016, 1e017, 1e018, 1e019, //
1212 1e020, 1e021, 1e022, 1e023, 1e024, 1e025, 1e026, 1e027, 1e028, 1e029, //
1213 1e030, 1e031, 1e032, 1e033, 1e034, 1e035, 1e036, 1e037, 1e038, 1e039, //
1214 1e040, 1e041, 1e042, 1e043, 1e044, 1e045, 1e046, 1e047, 1e048, 1e049, //
1215 1e050, 1e051, 1e052, 1e053, 1e054, 1e055, 1e056, 1e057, 1e058, 1e059, //
1216 1e060, 1e061, 1e062, 1e063, 1e064, 1e065, 1e066, 1e067, 1e068, 1e069, //
1217 1e070, 1e071, 1e072, 1e073, 1e074, 1e075, 1e076, 1e077, 1e078, 1e079, //
1218 1e080, 1e081, 1e082, 1e083, 1e084, 1e085, 1e086, 1e087, 1e088, 1e089, //
1219 1e090, 1e091, 1e092, 1e093, 1e094, 1e095, 1e096, 1e097, 1e098, 1e099, //
1220 1e100, 1e101, 1e102, 1e103, 1e104, 1e105, 1e106, 1e107, 1e108, 1e109, //
1221 1e110, 1e111, 1e112, 1e113, 1e114, 1e115, 1e116, 1e117, 1e118, 1e119, //
1222 1e120, 1e121, 1e122, 1e123, 1e124, 1e125, 1e126, 1e127, 1e128, 1e129, //
1223 1e130, 1e131, 1e132, 1e133, 1e134, 1e135, 1e136, 1e137, 1e138, 1e139, //
1224 1e140, 1e141, 1e142, 1e143, 1e144, 1e145, 1e146, 1e147, 1e148, 1e149, //
1225 1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159, //
1226 1e160, 1e161, 1e162, 1e163, 1e164, 1e165, 1e166, 1e167, 1e168, 1e169, //
1227 1e170, 1e171, 1e172, 1e173, 1e174, 1e175, 1e176, 1e177, 1e178, 1e179, //
1228 1e180, 1e181, 1e182, 1e183, 1e184, 1e185, 1e186, 1e187, 1e188, 1e189, //
1229 1e190, 1e191, 1e192, 1e193, 1e194, 1e195, 1e196, 1e197, 1e198, 1e199, //
1230 1e200, 1e201, 1e202, 1e203, 1e204, 1e205, 1e206, 1e207, 1e208, 1e209, //
1231 1e210, 1e211, 1e212, 1e213, 1e214, 1e215, 1e216, 1e217, 1e218, 1e219, //
1232 1e220, 1e221, 1e222, 1e223, 1e224, 1e225, 1e226, 1e227, 1e228, 1e229, //
1233 1e230, 1e231, 1e232, 1e233, 1e234, 1e235, 1e236, 1e237, 1e238, 1e239, //
1234 1e240, 1e241, 1e242, 1e243, 1e244, 1e245, 1e246, 1e247, 1e248, 1e249, //
1235 1e250, 1e251, 1e252, 1e253, 1e254, 1e255, 1e256, 1e257, 1e258, 1e259, //
1236 1e260, 1e261, 1e262, 1e263, 1e264, 1e265, 1e266, 1e267, 1e268, 1e269, //
1237 1e270, 1e271, 1e272, 1e273, 1e274, 1e275, 1e276, 1e277, 1e278, 1e279, //
1238 1e280, 1e281, 1e282, 1e283, 1e284, 1e285, 1e286, 1e287, 1e288, 1e289, //
1239 1e290, 1e291, 1e292, 1e293, 1e294, 1e295, 1e296, 1e297, 1e298, 1e299, //
1240 1e300, 1e301, 1e302, 1e303, 1e304, 1e305, 1e306, 1e307, 1e308,
1243 macro_rules! deserialize_number {
1244 ($method:ident) => {
1245 fn $method<V>(self, visitor: V) -> Result<V::Value>
1247 V: de::Visitor<'de>,
1249 self.deserialize_number(visitor)
1254 #[cfg(not(feature = "unbounded_depth
"))]
1255 macro_rules! if_checking_recursion_limit {
1261 #[cfg(feature = "unbounded_depth
")]
1262 macro_rules! if_checking_recursion_limit {
1263 ($this:ident $($body:tt)*) => {
1264 if !$this.disable_recursion_limit {
1270 macro_rules! check_recursion {
1271 ($this:ident $($body:tt)*) => {
1272 if_checking_recursion_limit! {
1273 $this.remaining_depth -= 1;
1274 if $this.remaining_depth == 0 {
1275 return Err($this.peek_error(ErrorCode::RecursionLimitExceeded));
1281 if_checking_recursion_limit! {
1282 $this.remaining_depth += 1;
1287 impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
1291 fn deserialize_any<V>(self, visitor: V) -> Result<V::Value>
1293 V: de::Visitor<'de>,
1295 let peek = match tri!(self.parse_whitespace()) {
1298 return Err(self.peek_error(ErrorCode::EofWhileParsingValue));
1302 let value = match peek {
1305 tri!(self.parse_ident(b"ull
"));
1306 visitor.visit_unit()
1310 tri!(self.parse_ident(b"rue
"));
1311 visitor.visit_bool(true)
1315 tri!(self.parse_ident(b"alse
"));
1316 visitor.visit_bool(false)
1320 tri!(self.parse_any_number(false)).visit(visitor)
1322 b'0'..=b'9' => tri!(self.parse_any_number(true)).visit(visitor),
1325 self.scratch
.clear();
1326 match tri
!(self.read
.parse_str(&mut self.scratch
)) {
1327 Reference
::Borrowed(s
) => visitor
.visit_borrowed_str(s
),
1328 Reference
::Copied(s
) => visitor
.visit_str(s
),
1334 let ret
= visitor
.visit_seq(SeqAccess
::new(self));
1337 match (ret
, self.end_seq()) {
1338 (Ok(ret
), Ok(())) => Ok(ret
),
1339 (Err(err
), _
) | (_
, Err(err
)) => Err(err
),
1345 let ret
= visitor
.visit_map(MapAccess
::new(self));
1348 match (ret
, self.end_map()) {
1349 (Ok(ret
), Ok(())) => Ok(ret
),
1350 (Err(err
), _
) | (_
, Err(err
)) => Err(err
),
1353 _
=> Err(self.peek_error(ErrorCode
::ExpectedSomeValue
)),
1357 Ok(value
) => Ok(value
),
1358 // The de::Error impl creates errors with unknown line and column.
1359 // Fill in the position here by looking at the current index in the
1360 // input. There is no way to tell whether this should call `error`
1361 // or `peek_error` so pick the one that seems correct more often.
1362 // Worst case, the position is off by one character.
1363 Err(err
) => Err(self.fix_position(err
)),
1367 fn deserialize_bool
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1369 V
: de
::Visitor
<'de
>,
1371 let peek
= match tri
!(self.parse_whitespace()) {
1374 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1378 let value
= match peek
{
1381 tri
!(self.parse_ident(b
"rue"));
1382 visitor
.visit_bool(true)
1386 tri
!(self.parse_ident(b
"alse"));
1387 visitor
.visit_bool(false)
1389 _
=> Err(self.peek_invalid_type(&visitor
)),
1393 Ok(value
) => Ok(value
),
1394 Err(err
) => Err(self.fix_position(err
)),
1398 deserialize_number
!(deserialize_i8
);
1399 deserialize_number
!(deserialize_i16
);
1400 deserialize_number
!(deserialize_i32
);
1401 deserialize_number
!(deserialize_i64
);
1402 deserialize_number
!(deserialize_u8
);
1403 deserialize_number
!(deserialize_u16
);
1404 deserialize_number
!(deserialize_u32
);
1405 deserialize_number
!(deserialize_u64
);
1406 #[cfg(not(feature = "float_roundtrip"))]
1407 deserialize_number
!(deserialize_f32
);
1408 deserialize_number
!(deserialize_f64
);
1410 #[cfg(feature = "float_roundtrip")]
1411 fn deserialize_f32
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1413 V
: de
::Visitor
<'de
>,
1415 self.single_precision
= true;
1416 let val
= self.deserialize_number(visitor
);
1417 self.single_precision
= false;
1421 serde_if_integer128
! {
1422 fn deserialize_i128
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1424 V
: de
::Visitor
<'de
>,
1426 let mut buf
= String
::new();
1428 match tri
!(self.parse_whitespace()) {
1435 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1439 tri
!(self.scan_integer128(&mut buf
));
1441 let value
= match buf
.parse() {
1442 Ok(int
) => visitor
.visit_i128(int
),
1444 return Err(self.error(ErrorCode
::NumberOutOfRange
));
1449 Ok(value
) => Ok(value
),
1450 Err(err
) => Err(self.fix_position(err
)),
1454 fn deserialize_u128
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1456 V
: de
::Visitor
<'de
>,
1458 match tri
!(self.parse_whitespace()) {
1460 return Err(self.peek_error(ErrorCode
::NumberOutOfRange
));
1464 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1468 let mut buf
= String
::new();
1469 tri
!(self.scan_integer128(&mut buf
));
1471 let value
= match buf
.parse() {
1472 Ok(int
) => visitor
.visit_u128(int
),
1474 return Err(self.error(ErrorCode
::NumberOutOfRange
));
1479 Ok(value
) => Ok(value
),
1480 Err(err
) => Err(self.fix_position(err
)),
1485 fn deserialize_char
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1487 V
: de
::Visitor
<'de
>,
1489 self.deserialize_str(visitor
)
1492 fn deserialize_str
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1494 V
: de
::Visitor
<'de
>,
1496 let peek
= match tri
!(self.parse_whitespace()) {
1499 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1503 let value
= match peek
{
1506 self.scratch.clear();
1507 match tri!(self.read.parse_str(&mut self.scratch)) {
1508 Reference::Borrowed(s) => visitor.visit_borrowed_str(s),
1509 Reference::Copied(s) => visitor.visit_str(s),
1512 _ => Err(self.peek_invalid_type(&visitor)),
1516 Ok(value) => Ok(value),
1517 Err(err) => Err(self.fix_position(err)),
1521 fn deserialize_string<V>(self, visitor: V) -> Result<V::Value>
1523 V: de::Visitor<'de>,
1525 self.deserialize_str(visitor)
1528 /// Parses a JSON string as bytes. Note that this function does not check
1529 /// whether the bytes represent a valid UTF-8 string.
1531 /// The relevant part of the JSON specification is Section 8.2 of [RFC
1534 /// > When all the strings represented in a JSON text are composed entirely
1535 /// > of Unicode characters (however escaped), then that JSON text is
1536 /// > interoperable in the sense that all software implementations that
1537 /// > parse it will agree on the contents of names and of string values in
1538 /// > objects and arrays.
1540 /// > However, the ABNF in this specification allows member names and string
1541 /// > values to contain bit sequences that cannot encode Unicode characters;
1542 /// > for example, "\uDEAD
" (a single unpaired UTF-16 surrogate). Instances
1543 /// > of this have been observed, for example, when a library truncates a
1544 /// > UTF-16 string without checking whether the truncation split a
1545 /// > surrogate pair. The behavior of software that receives JSON texts
1546 /// > containing such values is unpredictable; for example, implementations
1547 /// > might return different values for the length of a string value or even
1548 /// > suffer fatal runtime exceptions.
1550 /// [RFC 7159]: https://tools.ietf.org/html/rfc7159
1552 /// The behavior of serde_json is specified to fail on non-UTF-8 strings
1553 /// when deserializing into Rust UTF-8 string types such as String, and
1554 /// succeed with non-UTF-8 bytes when deserializing using this method.
1556 /// Escape sequences are processed as usual, and for `\uXXXX` escapes it is
1557 /// still checked if the hex number represents a valid Unicode code point.
1561 /// You can use this to parse JSON strings containing invalid UTF-8 bytes.
1564 /// use serde_bytes::ByteBuf;
1566 /// fn look_at_bytes() -> Result<(), serde_json::Error> {
1567 /// let json_data = b"\"some bytes
: \xe5
\x00
\xe5
\"";
1568 /// let bytes: ByteBuf = serde_json::from_slice(json_data)?;
1570 /// assert_eq!(b'\xe5', bytes[12]);
1571 /// assert_eq!(b'\0', bytes[13]);
1572 /// assert_eq!(b'\xe5', bytes[14]);
1577 /// # look_at_bytes().unwrap();
1580 /// Backslash escape sequences like `\n` are still interpreted and required
1581 /// to be valid, and `\u` escape sequences are required to represent valid
1582 /// Unicode code points.
1585 /// use serde_bytes::ByteBuf;
1587 /// fn look_at_bytes() {
1588 /// let json_data = b"\"invalid unicode surrogate
: \\uD801
\"";
1589 /// let parsed: Result<ByteBuf, _> = serde_json::from_slice(json_data);
1591 /// assert!(parsed.is_err());
1593 /// let expected_msg = "unexpected end of hex escape at line
1 column
35";
1594 /// assert_eq!(expected_msg, parsed.unwrap_err().to_string());
1597 /// # look_at_bytes();
1599 fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value>
1601 V: de::Visitor<'de>,
1603 let peek = match tri!(self.parse_whitespace()) {
1606 return Err(self.peek_error(ErrorCode::EofWhileParsingValue));
1610 let value = match peek {
1613 self.scratch
.clear();
1614 match tri
!(self.read
.parse_str_raw(&mut self.scratch
)) {
1615 Reference
::Borrowed(b
) => visitor
.visit_borrowed_bytes(b
),
1616 Reference
::Copied(b
) => visitor
.visit_bytes(b
),
1619 b'
['
=> self.deserialize_seq(visitor
),
1620 _
=> Err(self.peek_invalid_type(&visitor
)),
1624 Ok(value
) => Ok(value
),
1625 Err(err
) => Err(self.fix_position(err
)),
1630 fn deserialize_byte_buf
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1632 V
: de
::Visitor
<'de
>,
1634 self.deserialize_bytes(visitor
)
1637 /// Parses a `null` as a None, and any other values as a `Some(...)`.
1639 fn deserialize_option
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1641 V
: de
::Visitor
<'de
>,
1643 match tri
!(self.parse_whitespace()) {
1646 tri
!(self.parse_ident(b
"ull"));
1647 visitor
.visit_none()
1649 _
=> visitor
.visit_some(self),
1653 fn deserialize_unit
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1655 V
: de
::Visitor
<'de
>,
1657 let peek
= match tri
!(self.parse_whitespace()) {
1660 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1664 let value
= match peek
{
1667 tri
!(self.parse_ident(b
"ull"));
1668 visitor
.visit_unit()
1670 _
=> Err(self.peek_invalid_type(&visitor
)),
1674 Ok(value
) => Ok(value
),
1675 Err(err
) => Err(self.fix_position(err
)),
1679 fn deserialize_unit_struct
<V
>(self, _name
: &'
static str, visitor
: V
) -> Result
<V
::Value
>
1681 V
: de
::Visitor
<'de
>,
1683 self.deserialize_unit(visitor
)
1686 /// Parses a newtype struct as the underlying value.
1688 fn deserialize_newtype_struct
<V
>(self, name
: &str, visitor
: V
) -> Result
<V
::Value
>
1690 V
: de
::Visitor
<'de
>,
1692 #[cfg(feature = "raw_value")]
1694 if name
== crate::raw
::TOKEN
{
1695 return self.deserialize_raw_value(visitor
);
1700 visitor
.visit_newtype_struct(self)
1703 fn deserialize_seq
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1705 V
: de
::Visitor
<'de
>,
1707 let peek
= match tri
!(self.parse_whitespace()) {
1710 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1714 let value
= match peek
{
1718 let ret
= visitor
.visit_seq(SeqAccess
::new(self));
1721 match (ret
, self.end_seq()) {
1722 (Ok(ret
), Ok(())) => Ok(ret
),
1723 (Err(err
), _
) | (_
, Err(err
)) => Err(err
),
1726 _
=> Err(self.peek_invalid_type(&visitor
)),
1730 Ok(value
) => Ok(value
),
1731 Err(err
) => Err(self.fix_position(err
)),
1735 fn deserialize_tuple
<V
>(self, _len
: usize, visitor
: V
) -> Result
<V
::Value
>
1737 V
: de
::Visitor
<'de
>,
1739 self.deserialize_seq(visitor
)
1742 fn deserialize_tuple_struct
<V
>(
1744 _name
: &'
static str,
1747 ) -> Result
<V
::Value
>
1749 V
: de
::Visitor
<'de
>,
1751 self.deserialize_seq(visitor
)
1754 fn deserialize_map
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
1756 V
: de
::Visitor
<'de
>,
1758 let peek
= match tri
!(self.parse_whitespace()) {
1761 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1765 let value
= match peek
{
1769 let ret
= visitor
.visit_map(MapAccess
::new(self));
1772 match (ret
, self.end_map()) {
1773 (Ok(ret
), Ok(())) => Ok(ret
),
1774 (Err(err
), _
) | (_
, Err(err
)) => Err(err
),
1777 _
=> Err(self.peek_invalid_type(&visitor
)),
1781 Ok(value
) => Ok(value
),
1782 Err(err
) => Err(self.fix_position(err
)),
1786 fn deserialize_struct
<V
>(
1788 _name
: &'
static str,
1789 _fields
: &'
static [&'
static str],
1791 ) -> Result
<V
::Value
>
1793 V
: de
::Visitor
<'de
>,
1795 let peek
= match tri
!(self.parse_whitespace()) {
1798 return Err(self.peek_error(ErrorCode
::EofWhileParsingValue
));
1802 let value
= match peek
{
1806 let ret
= visitor
.visit_seq(SeqAccess
::new(self));
1809 match (ret
, self.end_seq()) {
1810 (Ok(ret
), Ok(())) => Ok(ret
),
1811 (Err(err
), _
) | (_
, Err(err
)) => Err(err
),
1817 let ret
= visitor
.visit_map(MapAccess
::new(self));
1820 match (ret
, self.end_map()) {
1821 (Ok(ret
), Ok(())) => Ok(ret
),
1822 (Err(err
), _
) | (_
, Err(err
)) => Err(err
),
1825 _
=> Err(self.peek_invalid_type(&visitor
)),
1829 Ok(value
) => Ok(value
),
1830 Err(err
) => Err(self.fix_position(err
)),
1834 /// Parses an enum as an object like `{"$KEY":$VALUE}`, where $VALUE is either a straight
1835 /// value, a `[..]`, or a `{..}`.
1837 fn deserialize_enum
<V
>(
1840 _variants
: &'
static [&'
static str],
1842 ) -> Result
<V
::Value
>
1844 V
: de
::Visitor
<'de
>,
1846 match tri
!(self.parse_whitespace()) {
1850 let value
= tri
!(visitor
.visit_enum(VariantAccess
::new(self)));
1853 match tri
!(self.parse_whitespace()) {
1858 Some(_
) => Err(self.error(ErrorCode
::ExpectedSomeValue
)),
1859 None
=> Err(self.error(ErrorCode
::EofWhileParsingObject
)),
1862 Some(b'
"') => visitor.visit_enum(UnitVariantAccess::new(self)),
1863 Some(_) => Err(self.peek_error(ErrorCode::ExpectedSomeValue)),
1864 None => Err(self.peek_error(ErrorCode::EofWhileParsingValue)),
1868 fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value>
1870 V: de::Visitor<'de>,
1872 self.deserialize_str(visitor)
1875 fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value>
1877 V: de::Visitor<'de>,
1879 tri!(self.ignore_value());
1880 visitor.visit_unit()
1884 struct SeqAccess<'a, R: 'a> {
1885 de: &'a mut Deserializer<R>,
1889 impl<'a, R: 'a> SeqAccess<'a, R> {
1890 fn new(de: &'a mut Deserializer<R>) -> Self {
1891 SeqAccess { de, first: true }
1895 impl<'de, 'a, R: Read<'de> + 'a> de::SeqAccess<'de> for SeqAccess<'a, R> {
1898 fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>
1900 T: de::DeserializeSeed<'de>,
1902 let peek = match tri!(self.de.parse_whitespace()) {
1906 Some(b',') if !self.first => {
1908 tri!(self.de.parse_whitespace())
1915 return Err(self.de.peek_error(ErrorCode::ExpectedListCommaOrEnd));
1919 return Err(self.de.peek_error(ErrorCode::EofWhileParsingList));
1924 Some(b']') => Err(self.de.peek_error(ErrorCode::TrailingComma)),
1925 Some(_) => Ok(Some(tri!(seed.deserialize(&mut *self.de)))),
1926 None => Err(self.de.peek_error(ErrorCode::EofWhileParsingValue)),
1931 struct MapAccess<'a, R: 'a> {
1932 de: &'a mut Deserializer<R>,
1936 impl<'a, R: 'a> MapAccess<'a, R> {
1937 fn new(de: &'a mut Deserializer<R>) -> Self {
1938 MapAccess { de, first: true }
1942 impl<'de, 'a, R: Read<'de> + 'a> de::MapAccess<'de> for MapAccess<'a, R> {
1945 fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>>
1947 K: de::DeserializeSeed<'de>,
1949 let peek = match tri!(self.de.parse_whitespace()) {
1953 Some(b',') if !self.first => {
1955 tri!(self.de.parse_whitespace())
1962 return Err(self.de.peek_error(ErrorCode::ExpectedObjectCommaOrEnd));
1966 return Err(self.de.peek_error(ErrorCode::EofWhileParsingObject));
1971 Some(b'"'
) => seed
.deserialize(MapKey { de: &mut *self.de }
).map(Some
),
1972 Some(b'
}'
) => Err(self.de
.peek_error(ErrorCode
::TrailingComma
)),
1973 Some(_
) => Err(self.de
.peek_error(ErrorCode
::KeyMustBeAString
)),
1974 None
=> Err(self.de
.peek_error(ErrorCode
::EofWhileParsingValue
)),
1978 fn next_value_seed
<V
>(&mut self, seed
: V
) -> Result
<V
::Value
>
1980 V
: de
::DeserializeSeed
<'de
>,
1982 tri
!(self.de
.parse_object_colon());
1984 seed
.deserialize(&mut *self.de
)
1988 struct VariantAccess
<'a
, R
: 'a
> {
1989 de
: &'a
mut Deserializer
<R
>,
1992 impl<'a
, R
: 'a
> VariantAccess
<'a
, R
> {
1993 fn new(de
: &'a
mut Deserializer
<R
>) -> Self {
1994 VariantAccess { de }
1998 impl<'de
, 'a
, R
: Read
<'de
> + 'a
> de
::EnumAccess
<'de
> for VariantAccess
<'a
, R
> {
2000 type Variant
= Self;
2002 fn variant_seed
<V
>(self, seed
: V
) -> Result
<(V
::Value
, Self)>
2004 V
: de
::DeserializeSeed
<'de
>,
2006 let val
= tri
!(seed
.deserialize(&mut *self.de
));
2007 tri
!(self.de
.parse_object_colon());
2012 impl<'de
, 'a
, R
: Read
<'de
> + 'a
> de
::VariantAccess
<'de
> for VariantAccess
<'a
, R
> {
2015 fn unit_variant(self) -> Result
<()> {
2016 de
::Deserialize
::deserialize(self.de
)
2019 fn newtype_variant_seed
<T
>(self, seed
: T
) -> Result
<T
::Value
>
2021 T
: de
::DeserializeSeed
<'de
>,
2023 seed
.deserialize(self.de
)
2026 fn tuple_variant
<V
>(self, _len
: usize, visitor
: V
) -> Result
<V
::Value
>
2028 V
: de
::Visitor
<'de
>,
2030 de
::Deserializer
::deserialize_seq(self.de
, visitor
)
2033 fn struct_variant
<V
>(self, fields
: &'
static [&'
static str], visitor
: V
) -> Result
<V
::Value
>
2035 V
: de
::Visitor
<'de
>,
2037 de
::Deserializer
::deserialize_struct(self.de
, "", fields
, visitor
)
2041 struct UnitVariantAccess
<'a
, R
: 'a
> {
2042 de
: &'a
mut Deserializer
<R
>,
2045 impl<'a
, R
: 'a
> UnitVariantAccess
<'a
, R
> {
2046 fn new(de
: &'a
mut Deserializer
<R
>) -> Self {
2047 UnitVariantAccess { de }
2051 impl<'de
, 'a
, R
: Read
<'de
> + 'a
> de
::EnumAccess
<'de
> for UnitVariantAccess
<'a
, R
> {
2053 type Variant
= Self;
2055 fn variant_seed
<V
>(self, seed
: V
) -> Result
<(V
::Value
, Self)>
2057 V
: de
::DeserializeSeed
<'de
>,
2059 let variant
= tri
!(seed
.deserialize(&mut *self.de
));
2064 impl<'de
, 'a
, R
: Read
<'de
> + 'a
> de
::VariantAccess
<'de
> for UnitVariantAccess
<'a
, R
> {
2067 fn unit_variant(self) -> Result
<()> {
2071 fn newtype_variant_seed
<T
>(self, _seed
: T
) -> Result
<T
::Value
>
2073 T
: de
::DeserializeSeed
<'de
>,
2075 Err(de
::Error
::invalid_type(
2076 Unexpected
::UnitVariant
,
2081 fn tuple_variant
<V
>(self, _len
: usize, _visitor
: V
) -> Result
<V
::Value
>
2083 V
: de
::Visitor
<'de
>,
2085 Err(de
::Error
::invalid_type(
2086 Unexpected
::UnitVariant
,
2091 fn struct_variant
<V
>(self, _fields
: &'
static [&'
static str], _visitor
: V
) -> Result
<V
::Value
>
2093 V
: de
::Visitor
<'de
>,
2095 Err(de
::Error
::invalid_type(
2096 Unexpected
::UnitVariant
,
2102 /// Only deserialize from this after peeking a '"' byte! Otherwise it may
2103 /// deserialize invalid JSON successfully.
2104 struct MapKey
<'a
, R
: 'a
> {
2105 de
: &'a
mut Deserializer
<R
>,
2108 macro_rules
! deserialize_integer_key
{
2109 ($method
:ident
=> $visit
:ident
) => {
2110 fn $method
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
2112 V
: de
::Visitor
<'de
>,
2115 self.de
.scratch
.clear();
2116 let string
= tri
!(self.de
.read
.parse_str(&mut self.de
.scratch
));
2117 match (string
.parse(), string
) {
2118 (Ok(integer
), _
) => visitor
.$
visit(integer
),
2119 (Err(_
), Reference
::Borrowed(s
)) => visitor
.visit_borrowed_str(s
),
2120 (Err(_
), Reference
::Copied(s
)) => visitor
.visit_str(s
),
2126 impl<'de
, 'a
, R
> de
::Deserializer
<'de
> for MapKey
<'a
, R
>
2133 fn deserialize_any
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
2135 V
: de
::Visitor
<'de
>,
2138 self.de
.scratch
.clear();
2139 match tri
!(self.de
.read
.parse_str(&mut self.de
.scratch
)) {
2140 Reference
::Borrowed(s
) => visitor
.visit_borrowed_str(s
),
2141 Reference
::Copied(s
) => visitor
.visit_str(s
),
2145 deserialize_integer_key
!(deserialize_i8
=> visit_i8
);
2146 deserialize_integer_key
!(deserialize_i16
=> visit_i16
);
2147 deserialize_integer_key
!(deserialize_i32
=> visit_i32
);
2148 deserialize_integer_key
!(deserialize_i64
=> visit_i64
);
2149 deserialize_integer_key
!(deserialize_u8
=> visit_u8
);
2150 deserialize_integer_key
!(deserialize_u16
=> visit_u16
);
2151 deserialize_integer_key
!(deserialize_u32
=> visit_u32
);
2152 deserialize_integer_key
!(deserialize_u64
=> visit_u64
);
2154 serde_if_integer128
! {
2155 deserialize_integer_key
!(deserialize_i128
=> visit_i128
);
2156 deserialize_integer_key
!(deserialize_u128
=> visit_u128
);
2160 fn deserialize_option
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
2162 V
: de
::Visitor
<'de
>,
2164 // Map keys cannot be null.
2165 visitor
.visit_some(self)
2169 fn deserialize_newtype_struct
<V
>(self, _name
: &'
static str, visitor
: V
) -> Result
<V
::Value
>
2171 V
: de
::Visitor
<'de
>,
2173 visitor
.visit_newtype_struct(self)
2177 fn deserialize_enum
<V
>(
2180 variants
: &'
static [&'
static str],
2182 ) -> Result
<V
::Value
>
2184 V
: de
::Visitor
<'de
>,
2186 self.de
.deserialize_enum(name
, variants
, visitor
)
2190 fn deserialize_bytes
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
2192 V
: de
::Visitor
<'de
>,
2194 self.de
.deserialize_bytes(visitor
)
2198 fn deserialize_byte_buf
<V
>(self, visitor
: V
) -> Result
<V
::Value
>
2200 V
: de
::Visitor
<'de
>,
2202 self.de
.deserialize_bytes(visitor
)
2205 forward_to_deserialize_any
! {
2206 bool
f32 f64 char str string unit unit_struct seq tuple tuple_struct map
2207 struct identifier ignored_any
2211 //////////////////////////////////////////////////////////////////////////////
2213 /// Iterator that deserializes a stream into multiple JSON values.
2215 /// A stream deserializer can be created from any JSON deserializer using the
2216 /// `Deserializer::into_iter` method.
2218 /// The data can consist of any JSON value. Values need to be a self-delineating value e.g.
2219 /// arrays, objects, or strings, or be followed by whitespace or a self-delineating value.
2222 /// use serde_json::{Deserializer, Value};
2225 /// let data = "{\"k\": 3}1\"cool\"\"stuff\" 3{} [0, 1, 2]";
2227 /// let stream = Deserializer::from_str(data).into_iter::<Value>();
2229 /// for value in stream {
2230 /// println!("{}", value.unwrap());
2234 pub struct StreamDeserializer
<'de
, R
, T
> {
2235 de
: Deserializer
<R
>,
2238 output
: PhantomData
<T
>,
2239 lifetime
: PhantomData
<&'
de ()>,
2242 impl<'de
, R
, T
> StreamDeserializer
<'de
, R
, T
>
2245 T
: de
::Deserialize
<'de
>,
2247 /// Create a JSON stream deserializer from one of the possible serde_json
2250 /// Typically it is more convenient to use one of these methods instead:
2252 /// - Deserializer::from_str(...).into_iter()
2253 /// - Deserializer::from_bytes(...).into_iter()
2254 /// - Deserializer::from_reader(...).into_iter()
2255 pub fn new(read
: R
) -> Self {
2256 let offset
= read
.byte_offset();
2257 StreamDeserializer
{
2258 de
: Deserializer
::new(read
),
2261 output
: PhantomData
,
2262 lifetime
: PhantomData
,
2266 /// Returns the number of bytes so far deserialized into a successful `T`.
2268 /// If a stream deserializer returns an EOF error, new data can be joined to
2269 /// `old_data[stream.byte_offset()..]` to try again.
2272 /// let data = b"[0] [1] [";
2274 /// let de = serde_json::Deserializer::from_slice(data);
2275 /// let mut stream = de.into_iter::<Vec<i32>>();
2276 /// assert_eq!(0, stream.byte_offset());
2278 /// println!("{:?}", stream.next()); // [0]
2279 /// assert_eq!(3, stream.byte_offset());
2281 /// println!("{:?}", stream.next()); // [1]
2282 /// assert_eq!(7, stream.byte_offset());
2284 /// println!("{:?}", stream.next()); // error
2285 /// assert_eq!(8, stream.byte_offset());
2287 /// // If err.is_eof(), can join the remaining data to new data and continue.
2288 /// let remaining = &data[stream.byte_offset()..];
2291 /// *Note:* In the future this method may be changed to return the number of
2292 /// bytes so far deserialized into a successful T *or* syntactically valid
2293 /// JSON skipped over due to a type error. See [serde-rs/json#70] for an
2294 /// example illustrating this.
2296 /// [serde-rs/json#70]: https://github.com/serde-rs/json/issues/70
2297 pub fn byte_offset(&self) -> usize {
2301 fn peek_end_of_value(&mut self) -> Result
<()> {
2302 match tri
!(self.de
.peek()) {
2303 Some(b' '
) | Some(b'
\n'
) | Some(b'
\t'
) | Some(b'
\r'
) | Some(b'
"') | Some(b'[')
2304 | Some(b']') | Some(b'{') | Some(b'}') | Some(b',') | Some(b':') | None => Ok(()),
2306 let position = self.de.read.peek_position();
2308 ErrorCode::TrailingCharacters,
2317 impl<'de, R, T> Iterator for StreamDeserializer<'de, R, T>
2320 T: de::Deserialize<'de>,
2322 type Item = Result<T>;
2324 fn next(&mut self) -> Option<Result<T>> {
2325 if R::should_early_return_if_failed && self.failed {
2329 // skip whitespaces, if any
2330 // this helps with trailing whitespaces, since whitespaces between
2331 // values are handled for us.
2332 match self.de.parse_whitespace() {
2334 self.offset = self.de.read.byte_offset();
2338 // If the value does not have a clear way to show the end of the value
2339 // (like numbers, null, true etc.) we have to look for whitespace or
2340 // the beginning of a self-delineated value.
2341 let self_delineated_value = match b {
2342 b'[' | b'"'
| b'
{'
=> true,
2345 self.offset
= self.de
.read
.byte_offset();
2346 let result
= de
::Deserialize
::deserialize(&mut self.de
);
2350 self.offset
= self.de
.read
.byte_offset();
2351 if self_delineated_value
{
2354 self.peek_end_of_value().map(|_
| value
)
2358 self.de
.read
.set_failed(&mut self.failed
);
2364 self.de
.read
.set_failed(&mut self.failed
);
2371 impl<'de
, R
, T
> FusedIterator
for StreamDeserializer
<'de
, R
, T
>
2373 R
: Read
<'de
> + Fused
,
2374 T
: de
::Deserialize
<'de
>,
2378 //////////////////////////////////////////////////////////////////////////////
2380 fn from_trait
<'de
, R
, T
>(read
: R
) -> Result
<T
>
2383 T
: de
::Deserialize
<'de
>,
2385 let mut de
= Deserializer
::new(read
);
2386 let value
= tri
!(de
::Deserialize
::deserialize(&mut de
));
2388 // Make sure the whole stream has been consumed.
2393 /// Deserialize an instance of type `T` from an IO stream of JSON.
2395 /// The content of the IO stream is deserialized directly from the stream
2396 /// without being buffered in memory by serde_json.
2398 /// When reading from a source against which short reads are not efficient, such
2399 /// as a [`File`], you will want to apply your own buffering because serde_json
2400 /// will not buffer the input. See [`std::io::BufReader`].
2402 /// It is expected that the input stream ends after the deserialized object.
2403 /// If the stream does not end, such as in the case of a persistent socket connection,
2404 /// this function will not return. It is possible instead to deserialize from a prefix of an input
2405 /// stream without looking for EOF by managing your own [`Deserializer`].
2407 /// Note that counter to intuition, this function is usually slower than
2408 /// reading a file completely into memory and then applying [`from_str`]
2409 /// or [`from_slice`] on it. See [issue #160].
2411 /// [`File`]: https://doc.rust-lang.org/std/fs/struct.File.html
2412 /// [`std::io::BufReader`]: https://doc.rust-lang.org/std/io/struct.BufReader.html
2413 /// [`from_str`]: ./fn.from_str.html
2414 /// [`from_slice`]: ./fn.from_slice.html
2415 /// [issue #160]: https://github.com/serde-rs/json/issues/160
2419 /// Reading the contents of a file.
2422 /// use serde::Deserialize;
2424 /// use std::error::Error;
2425 /// use std::fs::File;
2426 /// use std::io::BufReader;
2427 /// use std::path::Path;
2429 /// #[derive(Deserialize, Debug)]
2431 /// fingerprint: String,
2432 /// location: String,
2435 /// fn read_user_from_file<P: AsRef<Path>>(path: P) -> Result<User, Box<Error>> {
2436 /// // Open the file in read-only mode with buffer.
2437 /// let file = File::open(path)?;
2438 /// let reader = BufReader::new(file);
2440 /// // Read the JSON contents of the file as an instance of `User`.
2441 /// let u = serde_json::from_reader(reader)?;
2443 /// // Return the `User`.
2449 /// # fn fake_main() {
2450 /// let u = read_user_from_file("test.json").unwrap();
2451 /// println!("{:#?}", u);
2455 /// Reading from a persistent socket connection.
2458 /// use serde::Deserialize;
2460 /// use std::error::Error;
2461 /// use std::net::{TcpListener, TcpStream};
2463 /// #[derive(Deserialize, Debug)]
2465 /// fingerprint: String,
2466 /// location: String,
2469 /// fn read_user_from_stream(tcp_stream: TcpStream) -> Result<User, Box<dyn Error>> {
2470 /// let mut de = serde_json::Deserializer::from_reader(tcp_stream);
2471 /// let u = User::deserialize(&mut de)?;
2478 /// # fn fake_main() {
2479 /// let listener = TcpListener::bind("127.0.0.1:4000").unwrap();
2481 /// for stream in listener.incoming() {
2482 /// println!("{:#?}", read_user_from_stream(stream.unwrap()));
2489 /// This conversion can fail if the structure of the input does not match the
2490 /// structure expected by `T`, for example if `T` is a struct type but the input
2491 /// contains something other than a JSON map. It can also fail if the structure
2492 /// is correct but `T`'s implementation of `Deserialize` decides that something
2493 /// is wrong with the data, for example required struct fields are missing from
2494 /// the JSON map or some number is too big to fit in the expected primitive
2496 #[cfg(feature = "std")]
2497 pub fn from_reader
<R
, T
>(rdr
: R
) -> Result
<T
>
2500 T
: de
::DeserializeOwned
,
2502 from_trait(read
::IoRead
::new(rdr
))
2505 /// Deserialize an instance of type `T` from bytes of JSON text.
2510 /// use serde::Deserialize;
2512 /// #[derive(Deserialize, Debug)]
2514 /// fingerprint: String,
2515 /// location: String,
2519 /// // The type of `j` is `&[u8]`
2522 /// \"fingerprint\": \"0xF9BA143B95FF6D82\",
2523 /// \"location\": \"Menlo Park, CA\"
2526 /// let u: User = serde_json::from_slice(j).unwrap();
2527 /// println!("{:#?}", u);
2533 /// This conversion can fail if the structure of the input does not match the
2534 /// structure expected by `T`, for example if `T` is a struct type but the input
2535 /// contains something other than a JSON map. It can also fail if the structure
2536 /// is correct but `T`'s implementation of `Deserialize` decides that something
2537 /// is wrong with the data, for example required struct fields are missing from
2538 /// the JSON map or some number is too big to fit in the expected primitive
2540 pub fn from_slice
<'a
, T
>(v
: &'a
[u8]) -> Result
<T
>
2542 T
: de
::Deserialize
<'a
>,
2544 from_trait(read
::SliceRead
::new(v
))
2547 /// Deserialize an instance of type `T` from a string of JSON text.
2552 /// use serde::Deserialize;
2554 /// #[derive(Deserialize, Debug)]
2556 /// fingerprint: String,
2557 /// location: String,
2561 /// // The type of `j` is `&str`
2564 /// \"fingerprint\": \"0xF9BA143B95FF6D82\",
2565 /// \"location\": \"Menlo Park, CA\"
2568 /// let u: User = serde_json::from_str(j).unwrap();
2569 /// println!("{:#?}", u);
2575 /// This conversion can fail if the structure of the input does not match the
2576 /// structure expected by `T`, for example if `T` is a struct type but the input
2577 /// contains something other than a JSON map. It can also fail if the structure
2578 /// is correct but `T`'s implementation of `Deserialize` decides that something
2579 /// is wrong with the data, for example required struct fields are missing from
2580 /// the JSON map or some number is too big to fit in the expected primitive
2582 pub fn from_str
<'a
, T
>(s
: &'a
str) -> Result
<T
>
2584 T
: de
::Deserialize
<'a
>,
2586 from_trait(read
::StrRead
::new(s
))