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Quelle de.rs
Sprache: unbekannt
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Spracherkennung für: .rs vermutete Sprache: Unknown {[0] [0] [0]} [Methode: Schwerpunktbildung, einfache Gewichte, sechs Dimensionen]
//! 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")]
#[cfg_attr(docsrs, doc(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;
}
pub(crate) 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' ' | b'\n' | b'\t' | 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)
}
pub(crate) fn deserialize_number<'any, V>(&mut self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'any>,
{
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)),
}
}
#[cfg(feature = "float_roundtrip")]
pub(crate) fn do_deserialize_f32<'any, V>(&mut self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'any>,
{
self.single_precision = true;
let val = self.deserialize_number(visitor);
self.single_precision = false;
val
}
pub(crate) fn do_deserialize_i128<'any, V>(&mut self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'any>,
{
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)),
}
}
pub(crate) fn do_deserialize_u128<'any, V>(&mut self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'any>,
{
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 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) {
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) {
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) {
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) {
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('-');
}
tri!(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' | 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' | 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'[' | 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>,
{
tri!(self.parse_whitespace());
self.read.begin_raw_buffering();
tri!(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) => {
deserialize_number!($method, deserialize_number);
};
($method:ident, $using:ident) => {
fn $method<V>(self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'de>,
{
self.$using(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")]
deserialize_number!(deserialize_f32, do_deserialize_f32);
deserialize_number!(deserialize_i128, do_deserialize_i128);
deserialize_number!(deserialize_u128, do_deserialize_u128);
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_numeric_key {
($method:ident) => {
fn $method<V>(self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'de>,
{
self.deserialize_number(visitor)
}
};
($method:ident, $delegate:ident) => {
fn $method<V>(self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'de>,
{
self.de.eat_char();
match tri!(self.de.peek()) {
Some(b'0'..=b'9' | b'-') => {}
_ => return Err(self.de.error(ErrorCode::ExpectedNumericKey)),
}
let value = tri!(self.de.$delegate(visitor));
match tri!(self.de.peek()) {
Some(b'"') => self.de.eat_char(),
_ => return Err(self.de.peek_error(ErrorCode::ExpectedDoubleQuote)),
}
Ok(value)
}
};
}
impl<'de, 'a, R> MapKey<'a, R>
where
R: Read<'de>,
{
deserialize_numeric_key!(deserialize_number, deserialize_number);
}
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_numeric_key!(deserialize_i8);
deserialize_numeric_key!(deserialize_i16);
deserialize_numeric_key!(deserialize_i32);
deserialize_numeric_key!(deserialize_i64);
deserialize_numeric_key!(deserialize_i128, deserialize_i128);
deserialize_numeric_key!(deserialize_u8);
deserialize_numeric_key!(deserialize_u16);
deserialize_numeric_key!(deserialize_u32);
deserialize_numeric_key!(deserialize_u64);
deserialize_numeric_key!(deserialize_u128, deserialize_u128);
#[cfg(not(feature = "float_roundtrip"))]
deserialize_numeric_key!(deserialize_f32);
#[cfg(feature = "float_roundtrip")]
deserialize_numeric_key!(deserialize_f32, deserialize_f32);
deserialize_numeric_key!(deserialize_f64);
fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'de>,
{
self.de.eat_char();
let peek = match tri!(self.de.next_char()) {
Some(b) => b,
None => {
return Err(self.de.peek_error(ErrorCode::EofWhileParsingValue));
}
};
let value = match peek {
b't' => {
tri!(self.de.parse_ident(b"rue\""));
visitor.visit_bool(true)
}
b'f' => {
tri!(self.de.parse_ident(b"alse\""));
visitor.visit_bool(false)
}
_ => {
self.de.scratch.clear();
let s = tri!(self.de.read.parse_str(&mut self.de.scratch));
Err(de::Error::invalid_type(Unexpected::Str(&s), &visitor))
}
};
match value {
Ok(value) => Ok(value),
Err(err) => Err(self.de.fix_position(err)),
}
}
#[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! {
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' ' | b'\n' | b'\t' | b'\r' | b'"' | b'[' | b']' | b'{' | b'}' | b',' | 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 I/O stream of JSON.
///
/// The content of the I/O 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))
}
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