diff options
Diffstat (limited to 'third_party/rust/serde_json/src/de.rs')
| -rw-r--r-- | third_party/rust/serde_json/src/de.rs | 2606 |
1 files changed, 2606 insertions, 0 deletions
diff --git a/third_party/rust/serde_json/src/de.rs b/third_party/rust/serde_json/src/de.rs new file mode 100644 index 0000000000..88d0f2624d --- /dev/null +++ b/third_party/rust/serde_json/src/de.rs @@ -0,0 +1,2606 @@ +//! Deserialize JSON data to a Rust data structure. + +use crate::error::{Error, ErrorCode, Result}; +#[cfg(feature = "float_roundtrip")] +use crate::lexical; +use crate::number::Number; +use crate::read::{self, Fused, Reference}; +use alloc::string::String; +use alloc::vec::Vec; +#[cfg(feature = "float_roundtrip")] +use core::iter; +use core::iter::FusedIterator; +use core::marker::PhantomData; +use core::result; +use core::str::FromStr; +use serde::de::{self, Expected, Unexpected}; +use serde::forward_to_deserialize_any; + +#[cfg(feature = "arbitrary_precision")] +use crate::number::NumberDeserializer; + +pub use crate::read::{Read, SliceRead, StrRead}; + +#[cfg(feature = "std")] +pub use crate::read::IoRead; + +////////////////////////////////////////////////////////////////////////////// + +/// A structure that deserializes JSON into Rust values. +pub struct Deserializer<R> { + read: R, + scratch: Vec<u8>, + remaining_depth: u8, + #[cfg(feature = "float_roundtrip")] + single_precision: bool, + #[cfg(feature = "unbounded_depth")] + disable_recursion_limit: bool, +} + +impl<'de, R> Deserializer<R> +where + R: read::Read<'de>, +{ + /// Create a JSON deserializer from one of the possible serde_json input + /// sources. + /// + /// Typically it is more convenient to use one of these methods instead: + /// + /// - Deserializer::from_str + /// - Deserializer::from_slice + /// - Deserializer::from_reader + pub fn new(read: R) -> Self { + Deserializer { + read, + scratch: Vec::new(), + remaining_depth: 128, + #[cfg(feature = "float_roundtrip")] + single_precision: false, + #[cfg(feature = "unbounded_depth")] + disable_recursion_limit: false, + } + } +} + +#[cfg(feature = "std")] +impl<R> Deserializer<read::IoRead<R>> +where + R: crate::io::Read, +{ + /// Creates a JSON deserializer from an `io::Read`. + /// + /// Reader-based deserializers do not support deserializing borrowed types + /// like `&str`, since the `std::io::Read` trait has no non-copying methods + /// -- everything it does involves copying bytes out of the data source. + pub fn from_reader(reader: R) -> Self { + Deserializer::new(read::IoRead::new(reader)) + } +} + +impl<'a> Deserializer<read::SliceRead<'a>> { + /// Creates a JSON deserializer from a `&[u8]`. + pub fn from_slice(bytes: &'a [u8]) -> Self { + Deserializer::new(read::SliceRead::new(bytes)) + } +} + +impl<'a> Deserializer<read::StrRead<'a>> { + /// Creates a JSON deserializer from a `&str`. + pub fn from_str(s: &'a str) -> Self { + Deserializer::new(read::StrRead::new(s)) + } +} + +macro_rules! overflow { + ($a:ident * 10 + $b:ident, $c:expr) => { + match $c { + c => $a >= c / 10 && ($a > c / 10 || $b > c % 10), + } + }; +} + +pub(crate) enum ParserNumber { + F64(f64), + U64(u64), + I64(i64), + #[cfg(feature = "arbitrary_precision")] + String(String), +} + +impl ParserNumber { + fn visit<'de, V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + match self { + ParserNumber::F64(x) => visitor.visit_f64(x), + ParserNumber::U64(x) => visitor.visit_u64(x), + ParserNumber::I64(x) => visitor.visit_i64(x), + #[cfg(feature = "arbitrary_precision")] + ParserNumber::String(x) => visitor.visit_map(NumberDeserializer { number: x.into() }), + } + } + + fn invalid_type(self, exp: &dyn Expected) -> Error { + match self { + ParserNumber::F64(x) => de::Error::invalid_type(Unexpected::Float(x), exp), + ParserNumber::U64(x) => de::Error::invalid_type(Unexpected::Unsigned(x), exp), + ParserNumber::I64(x) => de::Error::invalid_type(Unexpected::Signed(x), exp), + #[cfg(feature = "arbitrary_precision")] + ParserNumber::String(_) => de::Error::invalid_type(Unexpected::Other("number"), exp), + } + } +} + +impl<'de, R: Read<'de>> Deserializer<R> { + /// The `Deserializer::end` method should be called after a value has been fully deserialized. + /// This allows the `Deserializer` to validate that the input stream is at the end or that it + /// only has trailing whitespace. + pub fn end(&mut self) -> Result<()> { + match tri!(self.parse_whitespace()) { + Some(_) => Err(self.peek_error(ErrorCode::TrailingCharacters)), + None => Ok(()), + } + } + + /// Turn a JSON deserializer into an iterator over values of type T. + pub fn into_iter<T>(self) -> StreamDeserializer<'de, R, T> + where + T: de::Deserialize<'de>, + { + // This cannot be an implementation of std::iter::IntoIterator because + // we need the caller to choose what T is. + let offset = self.read.byte_offset(); + StreamDeserializer { + de: self, + offset, + failed: false, + output: PhantomData, + lifetime: PhantomData, + } + } + + /// Parse arbitrarily deep JSON structures without any consideration for + /// overflowing the stack. + /// + /// You will want to provide some other way to protect against stack + /// overflows, such as by wrapping your Deserializer in the dynamically + /// growing stack adapter provided by the serde_stacker crate. Additionally + /// you will need to be careful around other recursive operations on the + /// parsed result which may overflow the stack after deserialization has + /// completed, including, but not limited to, Display and Debug and Drop + /// impls. + /// + /// *This method is only available if serde_json is built with the + /// `"unbounded_depth"` feature.* + /// + /// # Examples + /// + /// ``` + /// use serde::Deserialize; + /// use serde_json::Value; + /// + /// fn main() { + /// let mut json = String::new(); + /// for _ in 0..10000 { + /// json = format!("[{}]", json); + /// } + /// + /// let mut deserializer = serde_json::Deserializer::from_str(&json); + /// deserializer.disable_recursion_limit(); + /// let deserializer = serde_stacker::Deserializer::new(&mut deserializer); + /// let value = Value::deserialize(deserializer).unwrap(); + /// + /// carefully_drop_nested_arrays(value); + /// } + /// + /// fn carefully_drop_nested_arrays(value: Value) { + /// let mut stack = vec![value]; + /// while let Some(value) = stack.pop() { + /// if let Value::Array(array) = value { + /// stack.extend(array); + /// } + /// } + /// } + /// ``` + #[cfg(feature = "unbounded_depth")] + #[cfg_attr(docsrs, doc(cfg(feature = "unbounded_depth")))] + pub fn disable_recursion_limit(&mut self) { + self.disable_recursion_limit = true; + } + + fn peek(&mut self) -> Result<Option<u8>> { + self.read.peek() + } + + fn peek_or_null(&mut self) -> Result<u8> { + Ok(tri!(self.peek()).unwrap_or(b'\x00')) + } + + fn eat_char(&mut self) { + self.read.discard(); + } + + fn next_char(&mut self) -> Result<Option<u8>> { + self.read.next() + } + + fn next_char_or_null(&mut self) -> Result<u8> { + Ok(tri!(self.next_char()).unwrap_or(b'\x00')) + } + + /// Error caused by a byte from next_char(). + #[cold] + fn error(&self, reason: ErrorCode) -> Error { + let position = self.read.position(); + Error::syntax(reason, position.line, position.column) + } + + /// Error caused by a byte from peek(). + #[cold] + fn peek_error(&self, reason: ErrorCode) -> Error { + let position = self.read.peek_position(); + Error::syntax(reason, position.line, position.column) + } + + /// Returns the first non-whitespace byte without consuming it, or `None` if + /// EOF is encountered. + fn parse_whitespace(&mut self) -> Result<Option<u8>> { + loop { + match tri!(self.peek()) { + Some(b' ') | Some(b'\n') | Some(b'\t') | Some(b'\r') => { + self.eat_char(); + } + other => { + return Ok(other); + } + } + } + } + + #[cold] + fn peek_invalid_type(&mut self, exp: &dyn Expected) -> Error { + let err = match self.peek_or_null().unwrap_or(b'\x00') { + b'n' => { + self.eat_char(); + if let Err(err) = self.parse_ident(b"ull") { + return err; + } + de::Error::invalid_type(Unexpected::Unit, exp) + } + b't' => { + self.eat_char(); + if let Err(err) = self.parse_ident(b"rue") { + return err; + } + de::Error::invalid_type(Unexpected::Bool(true), exp) + } + b'f' => { + self.eat_char(); + if let Err(err) = self.parse_ident(b"alse") { + return err; + } + de::Error::invalid_type(Unexpected::Bool(false), exp) + } + b'-' => { + self.eat_char(); + match self.parse_any_number(false) { + Ok(n) => n.invalid_type(exp), + Err(err) => return err, + } + } + b'0'..=b'9' => match self.parse_any_number(true) { + Ok(n) => n.invalid_type(exp), + Err(err) => return err, + }, + b'"' => { + self.eat_char(); + self.scratch.clear(); + match self.read.parse_str(&mut self.scratch) { + Ok(s) => de::Error::invalid_type(Unexpected::Str(&s), exp), + Err(err) => return err, + } + } + b'[' => de::Error::invalid_type(Unexpected::Seq, exp), + b'{' => de::Error::invalid_type(Unexpected::Map, exp), + _ => self.peek_error(ErrorCode::ExpectedSomeValue), + }; + + self.fix_position(err) + } + + fn deserialize_number<V>(&mut self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'-' => { + self.eat_char(); + tri!(self.parse_integer(false)).visit(visitor) + } + b'0'..=b'9' => tri!(self.parse_integer(true)).visit(visitor), + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn scan_integer128(&mut self, buf: &mut String) -> Result<()> { + match tri!(self.next_char_or_null()) { + b'0' => { + buf.push('0'); + // There can be only one leading '0'. + match tri!(self.peek_or_null()) { + b'0'..=b'9' => Err(self.peek_error(ErrorCode::InvalidNumber)), + _ => Ok(()), + } + } + c @ b'1'..=b'9' => { + buf.push(c as char); + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + buf.push(c as char); + } + Ok(()) + } + _ => Err(self.error(ErrorCode::InvalidNumber)), + } + } + + #[cold] + fn fix_position(&self, err: Error) -> Error { + err.fix_position(move |code| self.error(code)) + } + + fn parse_ident(&mut self, ident: &[u8]) -> Result<()> { + for expected in ident { + match tri!(self.next_char()) { + None => { + return Err(self.error(ErrorCode::EofWhileParsingValue)); + } + Some(next) => { + if next != *expected { + return Err(self.error(ErrorCode::ExpectedSomeIdent)); + } + } + } + } + + Ok(()) + } + + fn parse_integer(&mut self, positive: bool) -> Result<ParserNumber> { + let next = match tri!(self.next_char()) { + Some(b) => b, + None => { + return Err(self.error(ErrorCode::EofWhileParsingValue)); + } + }; + + match next { + b'0' => { + // There can be only one leading '0'. + match tri!(self.peek_or_null()) { + b'0'..=b'9' => Err(self.peek_error(ErrorCode::InvalidNumber)), + _ => self.parse_number(positive, 0), + } + } + c @ b'1'..=b'9' => { + let mut significand = (c - b'0') as u64; + + loop { + match tri!(self.peek_or_null()) { + c @ b'0'..=b'9' => { + let digit = (c - b'0') as u64; + + // We need to be careful with overflow. If we can, + // try to keep the number as a `u64` until we grow + // too large. At that point, switch to parsing the + // value as a `f64`. + if overflow!(significand * 10 + digit, u64::max_value()) { + return Ok(ParserNumber::F64(tri!( + self.parse_long_integer(positive, significand), + ))); + } + + self.eat_char(); + significand = significand * 10 + digit; + } + _ => { + return self.parse_number(positive, significand); + } + } + } + } + _ => Err(self.error(ErrorCode::InvalidNumber)), + } + } + + fn parse_number(&mut self, positive: bool, significand: u64) -> Result<ParserNumber> { + Ok(match tri!(self.peek_or_null()) { + b'.' => ParserNumber::F64(tri!(self.parse_decimal(positive, significand, 0))), + b'e' | b'E' => ParserNumber::F64(tri!(self.parse_exponent(positive, significand, 0))), + _ => { + if positive { + ParserNumber::U64(significand) + } else { + let neg = (significand as i64).wrapping_neg(); + + // Convert into a float if we underflow, or on `-0`. + if neg >= 0 { + ParserNumber::F64(-(significand as f64)) + } else { + ParserNumber::I64(neg) + } + } + } + }) + } + + fn parse_decimal( + &mut self, + positive: bool, + mut significand: u64, + exponent_before_decimal_point: i32, + ) -> Result<f64> { + self.eat_char(); + + let mut exponent_after_decimal_point = 0; + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + let digit = (c - b'0') as u64; + + if overflow!(significand * 10 + digit, u64::max_value()) { + let exponent = exponent_before_decimal_point + exponent_after_decimal_point; + return self.parse_decimal_overflow(positive, significand, exponent); + } + + self.eat_char(); + significand = significand * 10 + digit; + exponent_after_decimal_point -= 1; + } + + // Error if there is not at least one digit after the decimal point. + if exponent_after_decimal_point == 0 { + match tri!(self.peek()) { + Some(_) => return Err(self.peek_error(ErrorCode::InvalidNumber)), + None => return Err(self.peek_error(ErrorCode::EofWhileParsingValue)), + } + } + + let exponent = exponent_before_decimal_point + exponent_after_decimal_point; + match tri!(self.peek_or_null()) { + b'e' | b'E' => self.parse_exponent(positive, significand, exponent), + _ => self.f64_from_parts(positive, significand, exponent), + } + } + + fn parse_exponent( + &mut self, + positive: bool, + significand: u64, + starting_exp: i32, + ) -> Result<f64> { + self.eat_char(); + + let positive_exp = match tri!(self.peek_or_null()) { + b'+' => { + self.eat_char(); + true + } + b'-' => { + self.eat_char(); + false + } + _ => true, + }; + + let next = match tri!(self.next_char()) { + Some(b) => b, + None => { + return Err(self.error(ErrorCode::EofWhileParsingValue)); + } + }; + + // Make sure a digit follows the exponent place. + let mut exp = match next { + c @ b'0'..=b'9' => (c - b'0') as i32, + _ => { + return Err(self.error(ErrorCode::InvalidNumber)); + } + }; + + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + let digit = (c - b'0') as i32; + + if overflow!(exp * 10 + digit, i32::max_value()) { + let zero_significand = significand == 0; + return self.parse_exponent_overflow(positive, zero_significand, positive_exp); + } + + exp = exp * 10 + digit; + } + + let final_exp = if positive_exp { + starting_exp.saturating_add(exp) + } else { + starting_exp.saturating_sub(exp) + }; + + self.f64_from_parts(positive, significand, final_exp) + } + + #[cfg(feature = "float_roundtrip")] + fn f64_from_parts(&mut self, positive: bool, significand: u64, exponent: i32) -> Result<f64> { + let f = if self.single_precision { + lexical::parse_concise_float::<f32>(significand, exponent) as f64 + } else { + lexical::parse_concise_float::<f64>(significand, exponent) + }; + + if f.is_infinite() { + Err(self.error(ErrorCode::NumberOutOfRange)) + } else { + Ok(if positive { f } else { -f }) + } + } + + #[cfg(not(feature = "float_roundtrip"))] + fn f64_from_parts( + &mut self, + positive: bool, + significand: u64, + mut exponent: i32, + ) -> Result<f64> { + let mut f = significand as f64; + loop { + match POW10.get(exponent.wrapping_abs() as usize) { + Some(&pow) => { + if exponent >= 0 { + f *= pow; + if f.is_infinite() { + return Err(self.error(ErrorCode::NumberOutOfRange)); + } + } else { + f /= pow; + } + break; + } + None => { + if f == 0.0 { + break; + } + if exponent >= 0 { + return Err(self.error(ErrorCode::NumberOutOfRange)); + } + f /= 1e308; + exponent += 308; + } + } + } + Ok(if positive { f } else { -f }) + } + + #[cfg(feature = "float_roundtrip")] + #[cold] + #[inline(never)] + fn parse_long_integer(&mut self, positive: bool, partial_significand: u64) -> Result<f64> { + // To deserialize floats we'll first push the integer and fraction + // parts, both as byte strings, into the scratch buffer and then feed + // both slices to lexical's parser. For example if the input is + // `12.34e5` we'll push b"1234" into scratch and then pass b"12" and + // b"34" to lexical. `integer_end` will be used to track where to split + // the scratch buffer. + // + // Note that lexical expects the integer part to contain *no* leading + // zeroes and the fraction part to contain *no* trailing zeroes. The + // first requirement is already handled by the integer parsing logic. + // The second requirement will be enforced just before passing the + // slices to lexical in f64_long_from_parts. + self.scratch.clear(); + self.scratch + .extend_from_slice(itoa::Buffer::new().format(partial_significand).as_bytes()); + + loop { + match tri!(self.peek_or_null()) { + c @ b'0'..=b'9' => { + self.scratch.push(c); + self.eat_char(); + } + b'.' => { + self.eat_char(); + return self.parse_long_decimal(positive, self.scratch.len()); + } + b'e' | b'E' => { + return self.parse_long_exponent(positive, self.scratch.len()); + } + _ => { + return self.f64_long_from_parts(positive, self.scratch.len(), 0); + } + } + } + } + + #[cfg(not(feature = "float_roundtrip"))] + #[cold] + #[inline(never)] + fn parse_long_integer(&mut self, positive: bool, significand: u64) -> Result<f64> { + let mut exponent = 0; + loop { + match tri!(self.peek_or_null()) { + b'0'..=b'9' => { + self.eat_char(); + // This could overflow... if your integer is gigabytes long. + // Ignore that possibility. + exponent += 1; + } + b'.' => { + return self.parse_decimal(positive, significand, exponent); + } + b'e' | b'E' => { + return self.parse_exponent(positive, significand, exponent); + } + _ => { + return self.f64_from_parts(positive, significand, exponent); + } + } + } + } + + #[cfg(feature = "float_roundtrip")] + #[cold] + fn parse_long_decimal(&mut self, positive: bool, integer_end: usize) -> Result<f64> { + let mut at_least_one_digit = integer_end < self.scratch.len(); + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + self.scratch.push(c); + self.eat_char(); + at_least_one_digit = true; + } + + if !at_least_one_digit { + match tri!(self.peek()) { + Some(_) => return Err(self.peek_error(ErrorCode::InvalidNumber)), + None => return Err(self.peek_error(ErrorCode::EofWhileParsingValue)), + } + } + + match tri!(self.peek_or_null()) { + b'e' | b'E' => self.parse_long_exponent(positive, integer_end), + _ => self.f64_long_from_parts(positive, integer_end, 0), + } + } + + #[cfg(feature = "float_roundtrip")] + fn parse_long_exponent(&mut self, positive: bool, integer_end: usize) -> Result<f64> { + self.eat_char(); + + let positive_exp = match tri!(self.peek_or_null()) { + b'+' => { + self.eat_char(); + true + } + b'-' => { + self.eat_char(); + false + } + _ => true, + }; + + let next = match tri!(self.next_char()) { + Some(b) => b, + None => { + return Err(self.error(ErrorCode::EofWhileParsingValue)); + } + }; + + // Make sure a digit follows the exponent place. + let mut exp = match next { + c @ b'0'..=b'9' => (c - b'0') as i32, + _ => { + return Err(self.error(ErrorCode::InvalidNumber)); + } + }; + + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + let digit = (c - b'0') as i32; + + if overflow!(exp * 10 + digit, i32::max_value()) { + let zero_significand = self.scratch.iter().all(|&digit| digit == b'0'); + return self.parse_exponent_overflow(positive, zero_significand, positive_exp); + } + + exp = exp * 10 + digit; + } + + let final_exp = if positive_exp { exp } else { -exp }; + + self.f64_long_from_parts(positive, integer_end, final_exp) + } + + // This cold code should not be inlined into the middle of the hot + // decimal-parsing loop above. + #[cfg(feature = "float_roundtrip")] + #[cold] + #[inline(never)] + fn parse_decimal_overflow( + &mut self, + positive: bool, + significand: u64, + exponent: i32, + ) -> Result<f64> { + let mut buffer = itoa::Buffer::new(); + let significand = buffer.format(significand); + let fraction_digits = -exponent as usize; + self.scratch.clear(); + if let Some(zeros) = fraction_digits.checked_sub(significand.len() + 1) { + self.scratch.extend(iter::repeat(b'0').take(zeros + 1)); + } + self.scratch.extend_from_slice(significand.as_bytes()); + let integer_end = self.scratch.len() - fraction_digits; + self.parse_long_decimal(positive, integer_end) + } + + #[cfg(not(feature = "float_roundtrip"))] + #[cold] + #[inline(never)] + fn parse_decimal_overflow( + &mut self, + positive: bool, + significand: u64, + exponent: i32, + ) -> Result<f64> { + // The next multiply/add would overflow, so just ignore all further + // digits. + while let b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + } + + match tri!(self.peek_or_null()) { + b'e' | b'E' => self.parse_exponent(positive, significand, exponent), + _ => self.f64_from_parts(positive, significand, exponent), + } + } + + // This cold code should not be inlined into the middle of the hot + // exponent-parsing loop above. + #[cold] + #[inline(never)] + fn parse_exponent_overflow( + &mut self, + positive: bool, + zero_significand: bool, + positive_exp: bool, + ) -> Result<f64> { + // Error instead of +/- infinity. + if !zero_significand && positive_exp { + return Err(self.error(ErrorCode::NumberOutOfRange)); + } + + while let b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + } + Ok(if positive { 0.0 } else { -0.0 }) + } + + #[cfg(feature = "float_roundtrip")] + fn f64_long_from_parts( + &mut self, + positive: bool, + integer_end: usize, + exponent: i32, + ) -> Result<f64> { + let integer = &self.scratch[..integer_end]; + let fraction = &self.scratch[integer_end..]; + + let f = if self.single_precision { + lexical::parse_truncated_float::<f32>(integer, fraction, exponent) as f64 + } else { + lexical::parse_truncated_float::<f64>(integer, fraction, exponent) + }; + + if f.is_infinite() { + Err(self.error(ErrorCode::NumberOutOfRange)) + } else { + Ok(if positive { f } else { -f }) + } + } + + fn parse_any_signed_number(&mut self) -> Result<ParserNumber> { + let peek = match tri!(self.peek()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'-' => { + self.eat_char(); + self.parse_any_number(false) + } + b'0'..=b'9' => self.parse_any_number(true), + _ => Err(self.peek_error(ErrorCode::InvalidNumber)), + }; + + let value = match tri!(self.peek()) { + Some(_) => Err(self.peek_error(ErrorCode::InvalidNumber)), + None => value, + }; + + match value { + Ok(value) => Ok(value), + // The de::Error impl creates errors with unknown line and column. + // Fill in the position here by looking at the current index in the + // input. There is no way to tell whether this should call `error` + // or `peek_error` so pick the one that seems correct more often. + // Worst case, the position is off by one character. + Err(err) => Err(self.fix_position(err)), + } + } + + #[cfg(not(feature = "arbitrary_precision"))] + fn parse_any_number(&mut self, positive: bool) -> Result<ParserNumber> { + self.parse_integer(positive) + } + + #[cfg(feature = "arbitrary_precision")] + fn parse_any_number(&mut self, positive: bool) -> Result<ParserNumber> { + let mut buf = String::with_capacity(16); + if !positive { + buf.push('-'); + } + self.scan_integer(&mut buf)?; + if positive { + if let Ok(unsigned) = buf.parse() { + return Ok(ParserNumber::U64(unsigned)); + } + } else { + if let Ok(signed) = buf.parse() { + return Ok(ParserNumber::I64(signed)); + } + } + Ok(ParserNumber::String(buf)) + } + + #[cfg(feature = "arbitrary_precision")] + fn scan_or_eof(&mut self, buf: &mut String) -> Result<u8> { + match tri!(self.next_char()) { + Some(b) => { + buf.push(b as char); + Ok(b) + } + None => Err(self.error(ErrorCode::EofWhileParsingValue)), + } + } + + #[cfg(feature = "arbitrary_precision")] + fn scan_integer(&mut self, buf: &mut String) -> Result<()> { + match tri!(self.scan_or_eof(buf)) { + b'0' => { + // There can be only one leading '0'. + match tri!(self.peek_or_null()) { + b'0'..=b'9' => Err(self.peek_error(ErrorCode::InvalidNumber)), + _ => self.scan_number(buf), + } + } + b'1'..=b'9' => loop { + match tri!(self.peek_or_null()) { + c @ b'0'..=b'9' => { + self.eat_char(); + buf.push(c as char); + } + _ => { + return self.scan_number(buf); + } + } + }, + _ => Err(self.error(ErrorCode::InvalidNumber)), + } + } + + #[cfg(feature = "arbitrary_precision")] + fn scan_number(&mut self, buf: &mut String) -> Result<()> { + match tri!(self.peek_or_null()) { + b'.' => self.scan_decimal(buf), + e @ b'e' | e @ b'E' => self.scan_exponent(e as char, buf), + _ => Ok(()), + } + } + + #[cfg(feature = "arbitrary_precision")] + fn scan_decimal(&mut self, buf: &mut String) -> Result<()> { + self.eat_char(); + buf.push('.'); + + let mut at_least_one_digit = false; + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + buf.push(c as char); + at_least_one_digit = true; + } + + if !at_least_one_digit { + match tri!(self.peek()) { + Some(_) => return Err(self.peek_error(ErrorCode::InvalidNumber)), + None => return Err(self.peek_error(ErrorCode::EofWhileParsingValue)), + } + } + + match tri!(self.peek_or_null()) { + e @ b'e' | e @ b'E' => self.scan_exponent(e as char, buf), + _ => Ok(()), + } + } + + #[cfg(feature = "arbitrary_precision")] + fn scan_exponent(&mut self, e: char, buf: &mut String) -> Result<()> { + self.eat_char(); + buf.push(e); + + match tri!(self.peek_or_null()) { + b'+' => { + self.eat_char(); + buf.push('+'); + } + b'-' => { + self.eat_char(); + buf.push('-'); + } + _ => {} + } + + // Make sure a digit follows the exponent place. + match tri!(self.scan_or_eof(buf)) { + b'0'..=b'9' => {} + _ => { + return Err(self.error(ErrorCode::InvalidNumber)); + } + } + + while let c @ b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + buf.push(c as char); + } + + Ok(()) + } + + fn parse_object_colon(&mut self) -> Result<()> { + match tri!(self.parse_whitespace()) { + Some(b':') => { + self.eat_char(); + Ok(()) + } + Some(_) => Err(self.peek_error(ErrorCode::ExpectedColon)), + None => Err(self.peek_error(ErrorCode::EofWhileParsingObject)), + } + } + + fn end_seq(&mut self) -> Result<()> { + match tri!(self.parse_whitespace()) { + Some(b']') => { + self.eat_char(); + Ok(()) + } + Some(b',') => { + self.eat_char(); + match self.parse_whitespace() { + Ok(Some(b']')) => Err(self.peek_error(ErrorCode::TrailingComma)), + _ => Err(self.peek_error(ErrorCode::TrailingCharacters)), + } + } + Some(_) => Err(self.peek_error(ErrorCode::TrailingCharacters)), + None => Err(self.peek_error(ErrorCode::EofWhileParsingList)), + } + } + + fn end_map(&mut self) -> Result<()> { + match tri!(self.parse_whitespace()) { + Some(b'}') => { + self.eat_char(); + Ok(()) + } + Some(b',') => Err(self.peek_error(ErrorCode::TrailingComma)), + Some(_) => Err(self.peek_error(ErrorCode::TrailingCharacters)), + None => Err(self.peek_error(ErrorCode::EofWhileParsingObject)), + } + } + + fn ignore_value(&mut self) -> Result<()> { + self.scratch.clear(); + let mut enclosing = None; + + loop { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let frame = match peek { + b'n' => { + self.eat_char(); + tri!(self.parse_ident(b"ull")); + None + } + b't' => { + self.eat_char(); + tri!(self.parse_ident(b"rue")); + None + } + b'f' => { + self.eat_char(); + tri!(self.parse_ident(b"alse")); + None + } + b'-' => { + self.eat_char(); + tri!(self.ignore_integer()); + None + } + b'0'..=b'9' => { + tri!(self.ignore_integer()); + None + } + b'"' => { + self.eat_char(); + tri!(self.read.ignore_str()); + None + } + frame @ b'[' | frame @ b'{' => { + self.scratch.extend(enclosing.take()); + self.eat_char(); + Some(frame) + } + _ => return Err(self.peek_error(ErrorCode::ExpectedSomeValue)), + }; + + let (mut accept_comma, mut frame) = match frame { + Some(frame) => (false, frame), + None => match enclosing.take() { + Some(frame) => (true, frame), + None => match self.scratch.pop() { + Some(frame) => (true, frame), + None => return Ok(()), + }, + }, + }; + + loop { + match tri!(self.parse_whitespace()) { + Some(b',') if accept_comma => { + self.eat_char(); + break; + } + Some(b']') if frame == b'[' => {} + Some(b'}') if frame == b'{' => {} + Some(_) => { + if accept_comma { + return Err(self.peek_error(match frame { + b'[' => ErrorCode::ExpectedListCommaOrEnd, + b'{' => ErrorCode::ExpectedObjectCommaOrEnd, + _ => unreachable!(), + })); + } else { + break; + } + } + None => { + return Err(self.peek_error(match frame { + b'[' => ErrorCode::EofWhileParsingList, + b'{' => ErrorCode::EofWhileParsingObject, + _ => unreachable!(), + })); + } + } + + self.eat_char(); + frame = match self.scratch.pop() { + Some(frame) => frame, + None => return Ok(()), + }; + accept_comma = true; + } + + if frame == b'{' { + match tri!(self.parse_whitespace()) { + Some(b'"') => self.eat_char(), + Some(_) => return Err(self.peek_error(ErrorCode::KeyMustBeAString)), + None => return Err(self.peek_error(ErrorCode::EofWhileParsingObject)), + } + tri!(self.read.ignore_str()); + match tri!(self.parse_whitespace()) { + Some(b':') => self.eat_char(), + Some(_) => return Err(self.peek_error(ErrorCode::ExpectedColon)), + None => return Err(self.peek_error(ErrorCode::EofWhileParsingObject)), + } + } + + enclosing = Some(frame); + } + } + + fn ignore_integer(&mut self) -> Result<()> { + match tri!(self.next_char_or_null()) { + b'0' => { + // There can be only one leading '0'. + if let b'0'..=b'9' = tri!(self.peek_or_null()) { + return Err(self.peek_error(ErrorCode::InvalidNumber)); + } + } + b'1'..=b'9' => { + while let b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + } + } + _ => { + return Err(self.error(ErrorCode::InvalidNumber)); + } + } + + match tri!(self.peek_or_null()) { + b'.' => self.ignore_decimal(), + b'e' | b'E' => self.ignore_exponent(), + _ => Ok(()), + } + } + + fn ignore_decimal(&mut self) -> Result<()> { + self.eat_char(); + + let mut at_least_one_digit = false; + while let b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + at_least_one_digit = true; + } + + if !at_least_one_digit { + return Err(self.peek_error(ErrorCode::InvalidNumber)); + } + + match tri!(self.peek_or_null()) { + b'e' | b'E' => self.ignore_exponent(), + _ => Ok(()), + } + } + + fn ignore_exponent(&mut self) -> Result<()> { + self.eat_char(); + + match tri!(self.peek_or_null()) { + b'+' | b'-' => self.eat_char(), + _ => {} + } + + // Make sure a digit follows the exponent place. + match tri!(self.next_char_or_null()) { + b'0'..=b'9' => {} + _ => { + return Err(self.error(ErrorCode::InvalidNumber)); + } + } + + while let b'0'..=b'9' = tri!(self.peek_or_null()) { + self.eat_char(); + } + + Ok(()) + } + + #[cfg(feature = "raw_value")] + fn deserialize_raw_value<V>(&mut self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.parse_whitespace()?; + self.read.begin_raw_buffering(); + self.ignore_value()?; + self.read.end_raw_buffering(visitor) + } +} + +impl FromStr for Number { + type Err = Error; + + fn from_str(s: &str) -> result::Result<Self, Self::Err> { + Deserializer::from_str(s) + .parse_any_signed_number() + .map(Into::into) + } +} + +#[cfg(not(feature = "float_roundtrip"))] +static POW10: [f64; 309] = [ + 1e000, 1e001, 1e002, 1e003, 1e004, 1e005, 1e006, 1e007, 1e008, 1e009, // + 1e010, 1e011, 1e012, 1e013, 1e014, 1e015, 1e016, 1e017, 1e018, 1e019, // + 1e020, 1e021, 1e022, 1e023, 1e024, 1e025, 1e026, 1e027, 1e028, 1e029, // + 1e030, 1e031, 1e032, 1e033, 1e034, 1e035, 1e036, 1e037, 1e038, 1e039, // + 1e040, 1e041, 1e042, 1e043, 1e044, 1e045, 1e046, 1e047, 1e048, 1e049, // + 1e050, 1e051, 1e052, 1e053, 1e054, 1e055, 1e056, 1e057, 1e058, 1e059, // + 1e060, 1e061, 1e062, 1e063, 1e064, 1e065, 1e066, 1e067, 1e068, 1e069, // + 1e070, 1e071, 1e072, 1e073, 1e074, 1e075, 1e076, 1e077, 1e078, 1e079, // + 1e080, 1e081, 1e082, 1e083, 1e084, 1e085, 1e086, 1e087, 1e088, 1e089, // + 1e090, 1e091, 1e092, 1e093, 1e094, 1e095, 1e096, 1e097, 1e098, 1e099, // + 1e100, 1e101, 1e102, 1e103, 1e104, 1e105, 1e106, 1e107, 1e108, 1e109, // + 1e110, 1e111, 1e112, 1e113, 1e114, 1e115, 1e116, 1e117, 1e118, 1e119, // + 1e120, 1e121, 1e122, 1e123, 1e124, 1e125, 1e126, 1e127, 1e128, 1e129, // + 1e130, 1e131, 1e132, 1e133, 1e134, 1e135, 1e136, 1e137, 1e138, 1e139, // + 1e140, 1e141, 1e142, 1e143, 1e144, 1e145, 1e146, 1e147, 1e148, 1e149, // + 1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159, // + 1e160, 1e161, 1e162, 1e163, 1e164, 1e165, 1e166, 1e167, 1e168, 1e169, // + 1e170, 1e171, 1e172, 1e173, 1e174, 1e175, 1e176, 1e177, 1e178, 1e179, // + 1e180, 1e181, 1e182, 1e183, 1e184, 1e185, 1e186, 1e187, 1e188, 1e189, // + 1e190, 1e191, 1e192, 1e193, 1e194, 1e195, 1e196, 1e197, 1e198, 1e199, // + 1e200, 1e201, 1e202, 1e203, 1e204, 1e205, 1e206, 1e207, 1e208, 1e209, // + 1e210, 1e211, 1e212, 1e213, 1e214, 1e215, 1e216, 1e217, 1e218, 1e219, // + 1e220, 1e221, 1e222, 1e223, 1e224, 1e225, 1e226, 1e227, 1e228, 1e229, // + 1e230, 1e231, 1e232, 1e233, 1e234, 1e235, 1e236, 1e237, 1e238, 1e239, // + 1e240, 1e241, 1e242, 1e243, 1e244, 1e245, 1e246, 1e247, 1e248, 1e249, // + 1e250, 1e251, 1e252, 1e253, 1e254, 1e255, 1e256, 1e257, 1e258, 1e259, // + 1e260, 1e261, 1e262, 1e263, 1e264, 1e265, 1e266, 1e267, 1e268, 1e269, // + 1e270, 1e271, 1e272, 1e273, 1e274, 1e275, 1e276, 1e277, 1e278, 1e279, // + 1e280, 1e281, 1e282, 1e283, 1e284, 1e285, 1e286, 1e287, 1e288, 1e289, // + 1e290, 1e291, 1e292, 1e293, 1e294, 1e295, 1e296, 1e297, 1e298, 1e299, // + 1e300, 1e301, 1e302, 1e303, 1e304, 1e305, 1e306, 1e307, 1e308, +]; + +macro_rules! deserialize_number { + ($method:ident) => { + fn $method<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_number(visitor) + } + }; +} + +#[cfg(not(feature = "unbounded_depth"))] +macro_rules! if_checking_recursion_limit { + ($($body:tt)*) => { + $($body)* + }; +} + +#[cfg(feature = "unbounded_depth")] +macro_rules! if_checking_recursion_limit { + ($this:ident $($body:tt)*) => { + if !$this.disable_recursion_limit { + $this $($body)* + } + }; +} + +macro_rules! check_recursion { + ($this:ident $($body:tt)*) => { + if_checking_recursion_limit! { + $this.remaining_depth -= 1; + if $this.remaining_depth == 0 { + return Err($this.peek_error(ErrorCode::RecursionLimitExceeded)); + } + } + + $this $($body)* + + if_checking_recursion_limit! { + $this.remaining_depth += 1; + } + }; +} + +impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> { + type Error = Error; + + #[inline] + fn deserialize_any<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'n' => { + self.eat_char(); + tri!(self.parse_ident(b"ull")); + visitor.visit_unit() + } + b't' => { + self.eat_char(); + tri!(self.parse_ident(b"rue")); + visitor.visit_bool(true) + } + b'f' => { + self.eat_char(); + tri!(self.parse_ident(b"alse")); + visitor.visit_bool(false) + } + b'-' => { + self.eat_char(); + tri!(self.parse_any_number(false)).visit(visitor) + } + b'0'..=b'9' => tri!(self.parse_any_number(true)).visit(visitor), + b'"' => { + self.eat_char(); + self.scratch.clear(); + match tri!(self.read.parse_str(&mut self.scratch)) { + Reference::Borrowed(s) => visitor.visit_borrowed_str(s), + Reference::Copied(s) => visitor.visit_str(s), + } + } + b'[' => { + check_recursion! { + self.eat_char(); + let ret = visitor.visit_seq(SeqAccess::new(self)); + } + + match (ret, self.end_seq()) { + (Ok(ret), Ok(())) => Ok(ret), + (Err(err), _) | (_, Err(err)) => Err(err), + } + } + b'{' => { + check_recursion! { + self.eat_char(); + let ret = visitor.visit_map(MapAccess::new(self)); + } + + match (ret, self.end_map()) { + (Ok(ret), Ok(())) => Ok(ret), + (Err(err), _) | (_, Err(err)) => Err(err), + } + } + _ => Err(self.peek_error(ErrorCode::ExpectedSomeValue)), + }; + + match value { + Ok(value) => Ok(value), + // The de::Error impl creates errors with unknown line and column. + // Fill in the position here by looking at the current index in the + // input. There is no way to tell whether this should call `error` + // or `peek_error` so pick the one that seems correct more often. + // Worst case, the position is off by one character. + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b't' => { + self.eat_char(); + tri!(self.parse_ident(b"rue")); + visitor.visit_bool(true) + } + b'f' => { + self.eat_char(); + tri!(self.parse_ident(b"alse")); + visitor.visit_bool(false) + } + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + deserialize_number!(deserialize_i8); + deserialize_number!(deserialize_i16); + deserialize_number!(deserialize_i32); + deserialize_number!(deserialize_i64); + deserialize_number!(deserialize_u8); + deserialize_number!(deserialize_u16); + deserialize_number!(deserialize_u32); + deserialize_number!(deserialize_u64); + #[cfg(not(feature = "float_roundtrip"))] + deserialize_number!(deserialize_f32); + deserialize_number!(deserialize_f64); + + #[cfg(feature = "float_roundtrip")] + fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.single_precision = true; + let val = self.deserialize_number(visitor); + self.single_precision = false; + val + } + + fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let mut buf = String::new(); + + match tri!(self.parse_whitespace()) { + Some(b'-') => { + self.eat_char(); + buf.push('-'); + } + Some(_) => {} + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + tri!(self.scan_integer128(&mut buf)); + + let value = match buf.parse() { + Ok(int) => visitor.visit_i128(int), + Err(_) => { + return Err(self.error(ErrorCode::NumberOutOfRange)); + } + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + match tri!(self.parse_whitespace()) { + Some(b'-') => { + return Err(self.peek_error(ErrorCode::NumberOutOfRange)); + } + Some(_) => {} + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + } + + let mut buf = String::new(); + tri!(self.scan_integer128(&mut buf)); + + let value = match buf.parse() { + Ok(int) => visitor.visit_u128(int), + Err(_) => { + return Err(self.error(ErrorCode::NumberOutOfRange)); + } + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_char<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_str(visitor) + } + + fn deserialize_str<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'"' => { + self.eat_char(); + self.scratch.clear(); + match tri!(self.read.parse_str(&mut self.scratch)) { + Reference::Borrowed(s) => visitor.visit_borrowed_str(s), + Reference::Copied(s) => visitor.visit_str(s), + } + } + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_string<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_str(visitor) + } + + /// Parses a JSON string as bytes. Note that this function does not check + /// whether the bytes represent a valid UTF-8 string. + /// + /// The relevant part of the JSON specification is Section 8.2 of [RFC + /// 7159]: + /// + /// > When all the strings represented in a JSON text are composed entirely + /// > of Unicode characters (however escaped), then that JSON text is + /// > interoperable in the sense that all software implementations that + /// > parse it will agree on the contents of names and of string values in + /// > objects and arrays. + /// > + /// > However, the ABNF in this specification allows member names and string + /// > values to contain bit sequences that cannot encode Unicode characters; + /// > for example, "\uDEAD" (a single unpaired UTF-16 surrogate). Instances + /// > of this have been observed, for example, when a library truncates a + /// > UTF-16 string without checking whether the truncation split a + /// > surrogate pair. The behavior of software that receives JSON texts + /// > containing such values is unpredictable; for example, implementations + /// > might return different values for the length of a string value or even + /// > suffer fatal runtime exceptions. + /// + /// [RFC 7159]: https://tools.ietf.org/html/rfc7159 + /// + /// The behavior of serde_json is specified to fail on non-UTF-8 strings + /// when deserializing into Rust UTF-8 string types such as String, and + /// succeed with non-UTF-8 bytes when deserializing using this method. + /// + /// Escape sequences are processed as usual, and for `\uXXXX` escapes it is + /// still checked if the hex number represents a valid Unicode code point. + /// + /// # Examples + /// + /// You can use this to parse JSON strings containing invalid UTF-8 bytes, + /// or unpaired surrogates. + /// + /// ``` + /// use serde_bytes::ByteBuf; + /// + /// fn look_at_bytes() -> Result<(), serde_json::Error> { + /// let json_data = b"\"some bytes: \xe5\x00\xe5\""; + /// let bytes: ByteBuf = serde_json::from_slice(json_data)?; + /// + /// assert_eq!(b'\xe5', bytes[12]); + /// assert_eq!(b'\0', bytes[13]); + /// assert_eq!(b'\xe5', bytes[14]); + /// + /// Ok(()) + /// } + /// # + /// # look_at_bytes().unwrap(); + /// ``` + /// + /// Backslash escape sequences like `\n` are still interpreted and required + /// to be valid. `\u` escape sequences are required to represent a valid + /// Unicode code point or lone surrogate. + /// + /// ``` + /// use serde_bytes::ByteBuf; + /// + /// fn look_at_bytes() -> Result<(), serde_json::Error> { + /// let json_data = b"\"lone surrogate: \\uD801\""; + /// let bytes: ByteBuf = serde_json::from_slice(json_data)?; + /// let expected = b"lone surrogate: \xED\xA0\x81"; + /// assert_eq!(expected, bytes.as_slice()); + /// Ok(()) + /// } + /// # + /// # look_at_bytes(); + /// ``` + fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'"' => { + self.eat_char(); + self.scratch.clear(); + match tri!(self.read.parse_str_raw(&mut self.scratch)) { + Reference::Borrowed(b) => visitor.visit_borrowed_bytes(b), + Reference::Copied(b) => visitor.visit_bytes(b), + } + } + b'[' => self.deserialize_seq(visitor), + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + #[inline] + fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_bytes(visitor) + } + + /// Parses a `null` as a None, and any other values as a `Some(...)`. + #[inline] + fn deserialize_option<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + match tri!(self.parse_whitespace()) { + Some(b'n') => { + self.eat_char(); + tri!(self.parse_ident(b"ull")); + visitor.visit_none() + } + _ => visitor.visit_some(self), + } + } + + fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'n' => { + self.eat_char(); + tri!(self.parse_ident(b"ull")); + visitor.visit_unit() + } + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_unit_struct<V>(self, _name: &'static str, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_unit(visitor) + } + + /// Parses a newtype struct as the underlying value. + #[inline] + fn deserialize_newtype_struct<V>(self, name: &str, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + #[cfg(feature = "raw_value")] + { + if name == crate::raw::TOKEN { + return self.deserialize_raw_value(visitor); + } + } + + let _ = name; + visitor.visit_newtype_struct(self) + } + + fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'[' => { + check_recursion! { + self.eat_char(); + let ret = visitor.visit_seq(SeqAccess::new(self)); + } + + match (ret, self.end_seq()) { + (Ok(ret), Ok(())) => Ok(ret), + (Err(err), _) | (_, Err(err)) => Err(err), + } + } + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_seq(visitor) + } + + fn deserialize_tuple_struct<V>( + self, + _name: &'static str, + _len: usize, + visitor: V, + ) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_seq(visitor) + } + + fn deserialize_map<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'{' => { + check_recursion! { + self.eat_char(); + let ret = visitor.visit_map(MapAccess::new(self)); + } + + match (ret, self.end_map()) { + (Ok(ret), Ok(())) => Ok(ret), + (Err(err), _) | (_, Err(err)) => Err(err), + } + } + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + fn deserialize_struct<V>( + self, + _name: &'static str, + _fields: &'static [&'static str], + visitor: V, + ) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + let peek = match tri!(self.parse_whitespace()) { + Some(b) => b, + None => { + return Err(self.peek_error(ErrorCode::EofWhileParsingValue)); + } + }; + + let value = match peek { + b'[' => { + check_recursion! { + self.eat_char(); + let ret = visitor.visit_seq(SeqAccess::new(self)); + } + + match (ret, self.end_seq()) { + (Ok(ret), Ok(())) => Ok(ret), + (Err(err), _) | (_, Err(err)) => Err(err), + } + } + b'{' => { + check_recursion! { + self.eat_char(); + let ret = visitor.visit_map(MapAccess::new(self)); + } + + match (ret, self.end_map()) { + (Ok(ret), Ok(())) => Ok(ret), + (Err(err), _) | (_, Err(err)) => Err(err), + } + } + _ => Err(self.peek_invalid_type(&visitor)), + }; + + match value { + Ok(value) => Ok(value), + Err(err) => Err(self.fix_position(err)), + } + } + + /// Parses an enum as an object like `{"$KEY":$VALUE}`, where $VALUE is either a straight + /// value, a `[..]`, or a `{..}`. + #[inline] + fn deserialize_enum<V>( + self, + _name: &str, + _variants: &'static [&'static str], + visitor: V, + ) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + match tri!(self.parse_whitespace()) { + Some(b'{') => { + check_recursion! { + self.eat_char(); + let value = tri!(visitor.visit_enum(VariantAccess::new(self))); + } + + match tri!(self.parse_whitespace()) { + Some(b'}') => { + self.eat_char(); + Ok(value) + } + Some(_) => Err(self.error(ErrorCode::ExpectedSomeValue)), + None => Err(self.error(ErrorCode::EofWhileParsingObject)), + } + } + Some(b'"') => visitor.visit_enum(UnitVariantAccess::new(self)), + Some(_) => Err(self.peek_error(ErrorCode::ExpectedSomeValue)), + None => Err(self.peek_error(ErrorCode::EofWhileParsingValue)), + } + } + + fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.deserialize_str(visitor) + } + + fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + tri!(self.ignore_value()); + visitor.visit_unit() + } +} + +struct SeqAccess<'a, R: 'a> { + de: &'a mut Deserializer<R>, + first: bool, +} + +impl<'a, R: 'a> SeqAccess<'a, R> { + fn new(de: &'a mut Deserializer<R>) -> Self { + SeqAccess { de, first: true } + } +} + +impl<'de, 'a, R: Read<'de> + 'a> de::SeqAccess<'de> for SeqAccess<'a, R> { + type Error = Error; + + fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>> + where + T: de::DeserializeSeed<'de>, + { + let peek = match tri!(self.de.parse_whitespace()) { + Some(b']') => { + return Ok(None); + } + Some(b',') if !self.first => { + self.de.eat_char(); + tri!(self.de.parse_whitespace()) + } + Some(b) => { + if self.first { + self.first = false; + Some(b) + } else { + return Err(self.de.peek_error(ErrorCode::ExpectedListCommaOrEnd)); + } + } + None => { + return Err(self.de.peek_error(ErrorCode::EofWhileParsingList)); + } + }; + + match peek { + Some(b']') => Err(self.de.peek_error(ErrorCode::TrailingComma)), + Some(_) => Ok(Some(tri!(seed.deserialize(&mut *self.de)))), + None => Err(self.de.peek_error(ErrorCode::EofWhileParsingValue)), + } + } +} + +struct MapAccess<'a, R: 'a> { + de: &'a mut Deserializer<R>, + first: bool, +} + +impl<'a, R: 'a> MapAccess<'a, R> { + fn new(de: &'a mut Deserializer<R>) -> Self { + MapAccess { de, first: true } + } +} + +impl<'de, 'a, R: Read<'de> + 'a> de::MapAccess<'de> for MapAccess<'a, R> { + type Error = Error; + + fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>> + where + K: de::DeserializeSeed<'de>, + { + let peek = match tri!(self.de.parse_whitespace()) { + Some(b'}') => { + return Ok(None); + } + Some(b',') if !self.first => { + self.de.eat_char(); + tri!(self.de.parse_whitespace()) + } + Some(b) => { + if self.first { + self.first = false; + Some(b) + } else { + return Err(self.de.peek_error(ErrorCode::ExpectedObjectCommaOrEnd)); + } + } + None => { + return Err(self.de.peek_error(ErrorCode::EofWhileParsingObject)); + } + }; + + match peek { + Some(b'"') => seed.deserialize(MapKey { de: &mut *self.de }).map(Some), + Some(b'}') => Err(self.de.peek_error(ErrorCode::TrailingComma)), + Some(_) => Err(self.de.peek_error(ErrorCode::KeyMustBeAString)), + None => Err(self.de.peek_error(ErrorCode::EofWhileParsingValue)), + } + } + + fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value> + where + V: de::DeserializeSeed<'de>, + { + tri!(self.de.parse_object_colon()); + + seed.deserialize(&mut *self.de) + } +} + +struct VariantAccess<'a, R: 'a> { + de: &'a mut Deserializer<R>, +} + +impl<'a, R: 'a> VariantAccess<'a, R> { + fn new(de: &'a mut Deserializer<R>) -> Self { + VariantAccess { de } + } +} + +impl<'de, 'a, R: Read<'de> + 'a> de::EnumAccess<'de> for VariantAccess<'a, R> { + type Error = Error; + type Variant = Self; + + fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self)> + where + V: de::DeserializeSeed<'de>, + { + let val = tri!(seed.deserialize(&mut *self.de)); + tri!(self.de.parse_object_colon()); + Ok((val, self)) + } +} + +impl<'de, 'a, R: Read<'de> + 'a> de::VariantAccess<'de> for VariantAccess<'a, R> { + type Error = Error; + + fn unit_variant(self) -> Result<()> { + de::Deserialize::deserialize(self.de) + } + + fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value> + where + T: de::DeserializeSeed<'de>, + { + seed.deserialize(self.de) + } + + fn tuple_variant<V>(self, _len: usize, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + de::Deserializer::deserialize_seq(self.de, visitor) + } + + fn struct_variant<V>(self, fields: &'static [&'static str], visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + de::Deserializer::deserialize_struct(self.de, "", fields, visitor) + } +} + +struct UnitVariantAccess<'a, R: 'a> { + de: &'a mut Deserializer<R>, +} + +impl<'a, R: 'a> UnitVariantAccess<'a, R> { + fn new(de: &'a mut Deserializer<R>) -> Self { + UnitVariantAccess { de } + } +} + +impl<'de, 'a, R: Read<'de> + 'a> de::EnumAccess<'de> for UnitVariantAccess<'a, R> { + type Error = Error; + type Variant = Self; + + fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self)> + where + V: de::DeserializeSeed<'de>, + { + let variant = tri!(seed.deserialize(&mut *self.de)); + Ok((variant, self)) + } +} + +impl<'de, 'a, R: Read<'de> + 'a> de::VariantAccess<'de> for UnitVariantAccess<'a, R> { + type Error = Error; + + fn unit_variant(self) -> Result<()> { + Ok(()) + } + + fn newtype_variant_seed<T>(self, _seed: T) -> Result<T::Value> + where + T: de::DeserializeSeed<'de>, + { + Err(de::Error::invalid_type( + Unexpected::UnitVariant, + &"newtype variant", + )) + } + + fn tuple_variant<V>(self, _len: usize, _visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + Err(de::Error::invalid_type( + Unexpected::UnitVariant, + &"tuple variant", + )) + } + + fn struct_variant<V>(self, _fields: &'static [&'static str], _visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + Err(de::Error::invalid_type( + Unexpected::UnitVariant, + &"struct variant", + )) + } +} + +/// Only deserialize from this after peeking a '"' byte! Otherwise it may +/// deserialize invalid JSON successfully. +struct MapKey<'a, R: 'a> { + de: &'a mut Deserializer<R>, +} + +macro_rules! deserialize_integer_key { + ($method:ident => $visit:ident) => { + fn $method<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.de.eat_char(); + self.de.scratch.clear(); + let string = tri!(self.de.read.parse_str(&mut self.de.scratch)); + match (string.parse(), string) { + (Ok(integer), _) => visitor.$visit(integer), + (Err(_), Reference::Borrowed(s)) => visitor.visit_borrowed_str(s), + (Err(_), Reference::Copied(s)) => visitor.visit_str(s), + } + } + }; +} + +impl<'de, 'a, R> de::Deserializer<'de> for MapKey<'a, R> +where + R: Read<'de>, +{ + type Error = Error; + + #[inline] + fn deserialize_any<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.de.eat_char(); + self.de.scratch.clear(); + match tri!(self.de.read.parse_str(&mut self.de.scratch)) { + Reference::Borrowed(s) => visitor.visit_borrowed_str(s), + Reference::Copied(s) => visitor.visit_str(s), + } + } + + deserialize_integer_key!(deserialize_i8 => visit_i8); + deserialize_integer_key!(deserialize_i16 => visit_i16); + deserialize_integer_key!(deserialize_i32 => visit_i32); + deserialize_integer_key!(deserialize_i64 => visit_i64); + deserialize_integer_key!(deserialize_i128 => visit_i128); + deserialize_integer_key!(deserialize_u8 => visit_u8); + deserialize_integer_key!(deserialize_u16 => visit_u16); + deserialize_integer_key!(deserialize_u32 => visit_u32); + deserialize_integer_key!(deserialize_u64 => visit_u64); + deserialize_integer_key!(deserialize_u128 => visit_u128); + + #[inline] + fn deserialize_option<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + // Map keys cannot be null. + visitor.visit_some(self) + } + + #[inline] + fn deserialize_newtype_struct<V>(self, name: &'static str, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + #[cfg(feature = "raw_value")] + { + if name == crate::raw::TOKEN { + return self.de.deserialize_raw_value(visitor); + } + } + + let _ = name; + visitor.visit_newtype_struct(self) + } + + #[inline] + fn deserialize_enum<V>( + self, + name: &'static str, + variants: &'static [&'static str], + visitor: V, + ) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.de.deserialize_enum(name, variants, visitor) + } + + #[inline] + fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.de.deserialize_bytes(visitor) + } + + #[inline] + fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value> + where + V: de::Visitor<'de>, + { + self.de.deserialize_bytes(visitor) + } + + forward_to_deserialize_any! { + bool f32 f64 char str string unit unit_struct seq tuple tuple_struct map + struct identifier ignored_any + } +} + +////////////////////////////////////////////////////////////////////////////// + +/// Iterator that deserializes a stream into multiple JSON values. +/// +/// A stream deserializer can be created from any JSON deserializer using the +/// `Deserializer::into_iter` method. +/// +/// The data can consist of any JSON value. Values need to be a self-delineating value e.g. +/// arrays, objects, or strings, or be followed by whitespace or a self-delineating value. +/// +/// ``` +/// use serde_json::{Deserializer, Value}; +/// +/// fn main() { +/// let data = "{\"k\": 3}1\"cool\"\"stuff\" 3{} [0, 1, 2]"; +/// +/// let stream = Deserializer::from_str(data).into_iter::<Value>(); +/// +/// for value in stream { +/// println!("{}", value.unwrap()); +/// } +/// } +/// ``` +pub struct StreamDeserializer<'de, R, T> { + de: Deserializer<R>, + offset: usize, + failed: bool, + output: PhantomData<T>, + lifetime: PhantomData<&'de ()>, +} + +impl<'de, R, T> StreamDeserializer<'de, R, T> +where + R: read::Read<'de>, + T: de::Deserialize<'de>, +{ + /// Create a JSON stream deserializer from one of the possible serde_json + /// input sources. + /// + /// Typically it is more convenient to use one of these methods instead: + /// + /// - Deserializer::from_str(...).into_iter() + /// - Deserializer::from_slice(...).into_iter() + /// - Deserializer::from_reader(...).into_iter() + pub fn new(read: R) -> Self { + let offset = read.byte_offset(); + StreamDeserializer { + de: Deserializer::new(read), + offset, + failed: false, + output: PhantomData, + lifetime: PhantomData, + } + } + + /// Returns the number of bytes so far deserialized into a successful `T`. + /// + /// If a stream deserializer returns an EOF error, new data can be joined to + /// `old_data[stream.byte_offset()..]` to try again. + /// + /// ``` + /// let data = b"[0] [1] ["; + /// + /// let de = serde_json::Deserializer::from_slice(data); + /// let mut stream = de.into_iter::<Vec<i32>>(); + /// assert_eq!(0, stream.byte_offset()); + /// + /// println!("{:?}", stream.next()); // [0] + /// assert_eq!(3, stream.byte_offset()); + /// + /// println!("{:?}", stream.next()); // [1] + /// assert_eq!(7, stream.byte_offset()); + /// + /// println!("{:?}", stream.next()); // error + /// assert_eq!(8, stream.byte_offset()); + /// + /// // If err.is_eof(), can join the remaining data to new data and continue. + /// let remaining = &data[stream.byte_offset()..]; + /// ``` + /// + /// *Note:* In the future this method may be changed to return the number of + /// bytes so far deserialized into a successful T *or* syntactically valid + /// JSON skipped over due to a type error. See [serde-rs/json#70] for an + /// example illustrating this. + /// + /// [serde-rs/json#70]: https://github.com/serde-rs/json/issues/70 + pub fn byte_offset(&self) -> usize { + self.offset + } + + fn peek_end_of_value(&mut self) -> Result<()> { + match tri!(self.de.peek()) { + Some(b' ') | Some(b'\n') | Some(b'\t') | Some(b'\r') | Some(b'"') | Some(b'[') + | Some(b']') | Some(b'{') | Some(b'}') | Some(b',') | Some(b':') | None => Ok(()), + Some(_) => { + let position = self.de.read.peek_position(); + Err(Error::syntax( + ErrorCode::TrailingCharacters, + position.line, + position.column, + )) + } + } + } +} + +impl<'de, R, T> Iterator for StreamDeserializer<'de, R, T> +where + R: Read<'de>, + T: de::Deserialize<'de>, +{ + type Item = Result<T>; + + fn next(&mut self) -> Option<Result<T>> { + if R::should_early_return_if_failed && self.failed { + return None; + } + + // skip whitespaces, if any + // this helps with trailing whitespaces, since whitespaces between + // values are handled for us. + match self.de.parse_whitespace() { + Ok(None) => { + self.offset = self.de.read.byte_offset(); + None + } + Ok(Some(b)) => { + // If the value does not have a clear way to show the end of the value + // (like numbers, null, true etc.) we have to look for whitespace or + // the beginning of a self-delineated value. + let self_delineated_value = match b { + b'[' | b'"' | b'{' => true, + _ => false, + }; + self.offset = self.de.read.byte_offset(); + let result = de::Deserialize::deserialize(&mut self.de); + + Some(match result { + Ok(value) => { + self.offset = self.de.read.byte_offset(); + if self_delineated_value { + Ok(value) + } else { + self.peek_end_of_value().map(|_| value) + } + } + Err(e) => { + self.de.read.set_failed(&mut self.failed); + Err(e) + } + }) + } + Err(e) => { + self.de.read.set_failed(&mut self.failed); + Some(Err(e)) + } + } + } +} + +impl<'de, R, T> FusedIterator for StreamDeserializer<'de, R, T> +where + R: Read<'de> + Fused, + T: de::Deserialize<'de>, +{ +} + +////////////////////////////////////////////////////////////////////////////// + +fn from_trait<'de, R, T>(read: R) -> Result<T> +where + R: Read<'de>, + T: de::Deserialize<'de>, +{ + let mut de = Deserializer::new(read); + let value = tri!(de::Deserialize::deserialize(&mut de)); + + // Make sure the whole stream has been consumed. + tri!(de.end()); + Ok(value) +} + +/// Deserialize an instance of type `T` from an IO stream of JSON. +/// +/// The content of the IO stream is deserialized directly from the stream +/// without being buffered in memory by serde_json. +/// +/// When reading from a source against which short reads are not efficient, such +/// as a [`File`], you will want to apply your own buffering because serde_json +/// will not buffer the input. See [`std::io::BufReader`]. +/// +/// It is expected that the input stream ends after the deserialized object. +/// If the stream does not end, such as in the case of a persistent socket connection, +/// this function will not return. It is possible instead to deserialize from a prefix of an input +/// stream without looking for EOF by managing your own [`Deserializer`]. +/// +/// Note that counter to intuition, this function is usually slower than +/// reading a file completely into memory and then applying [`from_str`] +/// or [`from_slice`] on it. See [issue #160]. +/// +/// [`File`]: https://doc.rust-lang.org/std/fs/struct.File.html +/// [`std::io::BufReader`]: https://doc.rust-lang.org/std/io/struct.BufReader.html +/// [`from_str`]: ./fn.from_str.html +/// [`from_slice`]: ./fn.from_slice.html +/// [issue #160]: https://github.com/serde-rs/json/issues/160 +/// +/// # Example +/// +/// Reading the contents of a file. +/// +/// ``` +/// use serde::Deserialize; +/// +/// use std::error::Error; +/// use std::fs::File; +/// use std::io::BufReader; +/// use std::path::Path; +/// +/// #[derive(Deserialize, Debug)] +/// struct User { +/// fingerprint: String, +/// location: String, +/// } +/// +/// fn read_user_from_file<P: AsRef<Path>>(path: P) -> Result<User, Box<dyn Error>> { +/// // Open the file in read-only mode with buffer. +/// let file = File::open(path)?; +/// let reader = BufReader::new(file); +/// +/// // Read the JSON contents of the file as an instance of `User`. +/// let u = serde_json::from_reader(reader)?; +/// +/// // Return the `User`. +/// Ok(u) +/// } +/// +/// fn main() { +/// # } +/// # fn fake_main() { +/// let u = read_user_from_file("test.json").unwrap(); +/// println!("{:#?}", u); +/// } +/// ``` +/// +/// Reading from a persistent socket connection. +/// +/// ``` +/// use serde::Deserialize; +/// +/// use std::error::Error; +/// use std::net::{TcpListener, TcpStream}; +/// +/// #[derive(Deserialize, Debug)] +/// struct User { +/// fingerprint: String, +/// location: String, +/// } +/// +/// fn read_user_from_stream(tcp_stream: TcpStream) -> Result<User, Box<dyn Error>> { +/// let mut de = serde_json::Deserializer::from_reader(tcp_stream); +/// let u = User::deserialize(&mut de)?; +/// +/// Ok(u) +/// } +/// +/// fn main() { +/// # } +/// # fn fake_main() { +/// let listener = TcpListener::bind("127.0.0.1:4000").unwrap(); +/// +/// for stream in listener.incoming() { +/// println!("{:#?}", read_user_from_stream(stream.unwrap())); +/// } +/// } +/// ``` +/// +/// # Errors +/// +/// This conversion can fail if the structure of the input does not match the +/// structure expected by `T`, for example if `T` is a struct type but the input +/// contains something other than a JSON map. It can also fail if the structure +/// is correct but `T`'s implementation of `Deserialize` decides that something +/// is wrong with the data, for example required struct fields are missing from +/// the JSON map or some number is too big to fit in the expected primitive +/// type. +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub fn from_reader<R, T>(rdr: R) -> Result<T> +where + R: crate::io::Read, + T: de::DeserializeOwned, +{ + from_trait(read::IoRead::new(rdr)) +} + +/// Deserialize an instance of type `T` from bytes of JSON text. +/// +/// # Example +/// +/// ``` +/// use serde::Deserialize; +/// +/// #[derive(Deserialize, Debug)] +/// struct User { +/// fingerprint: String, +/// location: String, +/// } +/// +/// fn main() { +/// // The type of `j` is `&[u8]` +/// let j = b" +/// { +/// \"fingerprint\": \"0xF9BA143B95FF6D82\", +/// \"location\": \"Menlo Park, CA\" +/// }"; +/// +/// let u: User = serde_json::from_slice(j).unwrap(); +/// println!("{:#?}", u); +/// } +/// ``` +/// +/// # Errors +/// +/// This conversion can fail if the structure of the input does not match the +/// structure expected by `T`, for example if `T` is a struct type but the input +/// contains something other than a JSON map. It can also fail if the structure +/// is correct but `T`'s implementation of `Deserialize` decides that something +/// is wrong with the data, for example required struct fields are missing from +/// the JSON map or some number is too big to fit in the expected primitive +/// type. +pub fn from_slice<'a, T>(v: &'a [u8]) -> Result<T> +where + T: de::Deserialize<'a>, +{ + from_trait(read::SliceRead::new(v)) +} + +/// Deserialize an instance of type `T` from a string of JSON text. +/// +/// # Example +/// +/// ``` +/// use serde::Deserialize; +/// +/// #[derive(Deserialize, Debug)] +/// struct User { +/// fingerprint: String, +/// location: String, +/// } +/// +/// fn main() { +/// // The type of `j` is `&str` +/// let j = " +/// { +/// \"fingerprint\": \"0xF9BA143B95FF6D82\", +/// \"location\": \"Menlo Park, CA\" +/// }"; +/// +/// let u: User = serde_json::from_str(j).unwrap(); +/// println!("{:#?}", u); +/// } +/// ``` +/// +/// # Errors +/// +/// This conversion can fail if the structure of the input does not match the +/// structure expected by `T`, for example if `T` is a struct type but the input +/// contains something other than a JSON map. It can also fail if the structure +/// is correct but `T`'s implementation of `Deserialize` decides that something +/// is wrong with the data, for example required struct fields are missing from +/// the JSON map or some number is too big to fit in the expected primitive +/// type. +pub fn from_str<'a, T>(s: &'a str) -> Result<T> +where + T: de::Deserialize<'a>, +{ + from_trait(read::StrRead::new(s)) +} |