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Diffstat (limited to 'vendor/serde_json/src/read.rs')
| -rw-r--r-- | vendor/serde_json/src/read.rs | 1004 |
1 files changed, 0 insertions, 1004 deletions
diff --git a/vendor/serde_json/src/read.rs b/vendor/serde_json/src/read.rs deleted file mode 100644 index 7446f28..0000000 --- a/vendor/serde_json/src/read.rs +++ /dev/null @@ -1,1004 +0,0 @@ -use crate::error::{Error, ErrorCode, Result}; -use alloc::vec::Vec; -use core::char; -use core::cmp; -use core::ops::Deref; -use core::str; - -#[cfg(feature = "std")] -use crate::io; -#[cfg(feature = "std")] -use crate::iter::LineColIterator; - -#[cfg(feature = "raw_value")] -use crate::raw::BorrowedRawDeserializer; -#[cfg(all(feature = "raw_value", feature = "std"))] -use crate::raw::OwnedRawDeserializer; -#[cfg(feature = "raw_value")] -use serde::de::Visitor; - -/// Trait used by the deserializer for iterating over input. This is manually -/// "specialized" for iterating over &[u8]. Once feature(specialization) is -/// stable we can use actual specialization. -/// -/// This trait is sealed and cannot be implemented for types outside of -/// `serde_json`. -pub trait Read<'de>: private::Sealed { - #[doc(hidden)] - fn next(&mut self) -> Result<Option<u8>>; - #[doc(hidden)] - fn peek(&mut self) -> Result<Option<u8>>; - - /// Only valid after a call to peek(). Discards the peeked byte. - #[doc(hidden)] - fn discard(&mut self); - - /// Position of the most recent call to next(). - /// - /// The most recent call was probably next() and not peek(), but this method - /// should try to return a sensible result if the most recent call was - /// actually peek() because we don't always know. - /// - /// Only called in case of an error, so performance is not important. - #[doc(hidden)] - fn position(&self) -> Position; - - /// Position of the most recent call to peek(). - /// - /// The most recent call was probably peek() and not next(), but this method - /// should try to return a sensible result if the most recent call was - /// actually next() because we don't always know. - /// - /// Only called in case of an error, so performance is not important. - #[doc(hidden)] - fn peek_position(&self) -> Position; - - /// Offset from the beginning of the input to the next byte that would be - /// returned by next() or peek(). - #[doc(hidden)] - fn byte_offset(&self) -> usize; - - /// Assumes the previous byte was a quotation mark. Parses a JSON-escaped - /// string until the next quotation mark using the given scratch space if - /// necessary. The scratch space is initially empty. - #[doc(hidden)] - fn parse_str<'s>(&'s mut self, scratch: &'s mut Vec<u8>) -> Result<Reference<'de, 's, str>>; - - /// Assumes the previous byte was a quotation mark. Parses a JSON-escaped - /// string until the next quotation mark using the given scratch space if - /// necessary. The scratch space is initially empty. - /// - /// This function returns the raw bytes in the string with escape sequences - /// expanded but without performing unicode validation. - #[doc(hidden)] - fn parse_str_raw<'s>( - &'s mut self, - scratch: &'s mut Vec<u8>, - ) -> Result<Reference<'de, 's, [u8]>>; - - /// Assumes the previous byte was a quotation mark. Parses a JSON-escaped - /// string until the next quotation mark but discards the data. - #[doc(hidden)] - fn ignore_str(&mut self) -> Result<()>; - - /// Assumes the previous byte was a hex escape sequence ('\u') in a string. - /// Parses next hexadecimal sequence. - #[doc(hidden)] - fn decode_hex_escape(&mut self) -> Result<u16>; - - /// Switch raw buffering mode on. - /// - /// This is used when deserializing `RawValue`. - #[cfg(feature = "raw_value")] - #[doc(hidden)] - fn begin_raw_buffering(&mut self); - - /// Switch raw buffering mode off and provides the raw buffered data to the - /// given visitor. - #[cfg(feature = "raw_value")] - #[doc(hidden)] - fn end_raw_buffering<V>(&mut self, visitor: V) -> Result<V::Value> - where - V: Visitor<'de>; - - /// Whether StreamDeserializer::next needs to check the failed flag. True - /// for IoRead, false for StrRead and SliceRead which can track failure by - /// truncating their input slice to avoid the extra check on every next - /// call. - #[doc(hidden)] - const should_early_return_if_failed: bool; - - /// Mark a persistent failure of StreamDeserializer, either by setting the - /// flag or by truncating the input data. - #[doc(hidden)] - fn set_failed(&mut self, failed: &mut bool); -} - -pub struct Position { - pub line: usize, - pub column: usize, -} - -pub enum Reference<'b, 'c, T> -where - T: ?Sized + 'static, -{ - Borrowed(&'b T), - Copied(&'c T), -} - -impl<'b, 'c, T> Deref for Reference<'b, 'c, T> -where - T: ?Sized + 'static, -{ - type Target = T; - - fn deref(&self) -> &Self::Target { - match *self { - Reference::Borrowed(b) => b, - Reference::Copied(c) => c, - } - } -} - -/// JSON input source that reads from a std::io input stream. -#[cfg(feature = "std")] -#[cfg_attr(docsrs, doc(cfg(feature = "std")))] -pub struct IoRead<R> -where - R: io::Read, -{ - iter: LineColIterator<io::Bytes<R>>, - /// Temporary storage of peeked byte. - ch: Option<u8>, - #[cfg(feature = "raw_value")] - raw_buffer: Option<Vec<u8>>, -} - -/// JSON input source that reads from a slice of bytes. -// -// This is more efficient than other iterators because peek() can be read-only -// and we can compute line/col position only if an error happens. -pub struct SliceRead<'a> { - slice: &'a [u8], - /// Index of the *next* byte that will be returned by next() or peek(). - index: usize, - #[cfg(feature = "raw_value")] - raw_buffering_start_index: usize, -} - -/// JSON input source that reads from a UTF-8 string. -// -// Able to elide UTF-8 checks by assuming that the input is valid UTF-8. -pub struct StrRead<'a> { - delegate: SliceRead<'a>, - #[cfg(feature = "raw_value")] - data: &'a str, -} - -// Prevent users from implementing the Read trait. -mod private { - pub trait Sealed {} -} - -////////////////////////////////////////////////////////////////////////////// - -#[cfg(feature = "std")] -impl<R> IoRead<R> -where - R: io::Read, -{ - /// Create a JSON input source to read from a std::io input stream. - pub fn new(reader: R) -> Self { - IoRead { - iter: LineColIterator::new(reader.bytes()), - ch: None, - #[cfg(feature = "raw_value")] - raw_buffer: None, - } - } -} - -#[cfg(feature = "std")] -impl<R> private::Sealed for IoRead<R> where R: io::Read {} - -#[cfg(feature = "std")] -impl<R> IoRead<R> -where - R: io::Read, -{ - fn parse_str_bytes<'s, T, F>( - &'s mut self, - scratch: &'s mut Vec<u8>, - validate: bool, - result: F, - ) -> Result<T> - where - T: 's, - F: FnOnce(&'s Self, &'s [u8]) -> Result<T>, - { - loop { - let ch = tri!(next_or_eof(self)); - if !ESCAPE[ch as usize] { - scratch.push(ch); - continue; - } - match ch { - b'"' => { - return result(self, scratch); - } - b'\\' => { - tri!(parse_escape(self, validate, scratch)); - } - _ => { - if validate { - return error(self, ErrorCode::ControlCharacterWhileParsingString); - } - scratch.push(ch); - } - } - } - } -} - -#[cfg(feature = "std")] -impl<'de, R> Read<'de> for IoRead<R> -where - R: io::Read, -{ - #[inline] - fn next(&mut self) -> Result<Option<u8>> { - match self.ch.take() { - Some(ch) => { - #[cfg(feature = "raw_value")] - { - if let Some(buf) = &mut self.raw_buffer { - buf.push(ch); - } - } - Ok(Some(ch)) - } - None => match self.iter.next() { - Some(Err(err)) => Err(Error::io(err)), - Some(Ok(ch)) => { - #[cfg(feature = "raw_value")] - { - if let Some(buf) = &mut self.raw_buffer { - buf.push(ch); - } - } - Ok(Some(ch)) - } - None => Ok(None), - }, - } - } - - #[inline] - fn peek(&mut self) -> Result<Option<u8>> { - match self.ch { - Some(ch) => Ok(Some(ch)), - None => match self.iter.next() { - Some(Err(err)) => Err(Error::io(err)), - Some(Ok(ch)) => { - self.ch = Some(ch); - Ok(self.ch) - } - None => Ok(None), - }, - } - } - - #[cfg(not(feature = "raw_value"))] - #[inline] - fn discard(&mut self) { - self.ch = None; - } - - #[cfg(feature = "raw_value")] - fn discard(&mut self) { - if let Some(ch) = self.ch.take() { - if let Some(buf) = &mut self.raw_buffer { - buf.push(ch); - } - } - } - - fn position(&self) -> Position { - Position { - line: self.iter.line(), - column: self.iter.col(), - } - } - - fn peek_position(&self) -> Position { - // The LineColIterator updates its position during peek() so it has the - // right one here. - self.position() - } - - fn byte_offset(&self) -> usize { - match self.ch { - Some(_) => self.iter.byte_offset() - 1, - None => self.iter.byte_offset(), - } - } - - fn parse_str<'s>(&'s mut self, scratch: &'s mut Vec<u8>) -> Result<Reference<'de, 's, str>> { - self.parse_str_bytes(scratch, true, as_str) - .map(Reference::Copied) - } - - fn parse_str_raw<'s>( - &'s mut self, - scratch: &'s mut Vec<u8>, - ) -> Result<Reference<'de, 's, [u8]>> { - self.parse_str_bytes(scratch, false, |_, bytes| Ok(bytes)) - .map(Reference::Copied) - } - - fn ignore_str(&mut self) -> Result<()> { - loop { - let ch = tri!(next_or_eof(self)); - if !ESCAPE[ch as usize] { - continue; - } - match ch { - b'"' => { - return Ok(()); - } - b'\\' => { - tri!(ignore_escape(self)); - } - _ => { - return error(self, ErrorCode::ControlCharacterWhileParsingString); - } - } - } - } - - fn decode_hex_escape(&mut self) -> Result<u16> { - let mut n = 0; - for _ in 0..4 { - match decode_hex_val(tri!(next_or_eof(self))) { - None => return error(self, ErrorCode::InvalidEscape), - Some(val) => { - n = (n << 4) + val; - } - } - } - Ok(n) - } - - #[cfg(feature = "raw_value")] - fn begin_raw_buffering(&mut self) { - self.raw_buffer = Some(Vec::new()); - } - - #[cfg(feature = "raw_value")] - fn end_raw_buffering<V>(&mut self, visitor: V) -> Result<V::Value> - where - V: Visitor<'de>, - { - let raw = self.raw_buffer.take().unwrap(); - let raw = match String::from_utf8(raw) { - Ok(raw) => raw, - Err(_) => return error(self, ErrorCode::InvalidUnicodeCodePoint), - }; - visitor.visit_map(OwnedRawDeserializer { - raw_value: Some(raw), - }) - } - - const should_early_return_if_failed: bool = true; - - #[inline] - #[cold] - fn set_failed(&mut self, failed: &mut bool) { - *failed = true; - } -} - -////////////////////////////////////////////////////////////////////////////// - -impl<'a> SliceRead<'a> { - /// Create a JSON input source to read from a slice of bytes. - pub fn new(slice: &'a [u8]) -> Self { - SliceRead { - slice, - index: 0, - #[cfg(feature = "raw_value")] - raw_buffering_start_index: 0, - } - } - - fn position_of_index(&self, i: usize) -> Position { - let mut position = Position { line: 1, column: 0 }; - for ch in &self.slice[..i] { - match *ch { - b'\n' => { - position.line += 1; - position.column = 0; - } - _ => { - position.column += 1; - } - } - } - position - } - - /// The big optimization here over IoRead is that if the string contains no - /// backslash escape sequences, the returned &str is a slice of the raw JSON - /// data so we avoid copying into the scratch space. - fn parse_str_bytes<'s, T, F>( - &'s mut self, - scratch: &'s mut Vec<u8>, - validate: bool, - result: F, - ) -> Result<Reference<'a, 's, T>> - where - T: ?Sized + 's, - F: for<'f> FnOnce(&'s Self, &'f [u8]) -> Result<&'f T>, - { - // Index of the first byte not yet copied into the scratch space. - let mut start = self.index; - - loop { - while self.index < self.slice.len() && !ESCAPE[self.slice[self.index] as usize] { - self.index += 1; - } - if self.index == self.slice.len() { - return error(self, ErrorCode::EofWhileParsingString); - } - match self.slice[self.index] { - b'"' => { - if scratch.is_empty() { - // Fast path: return a slice of the raw JSON without any - // copying. - let borrowed = &self.slice[start..self.index]; - self.index += 1; - return result(self, borrowed).map(Reference::Borrowed); - } else { - scratch.extend_from_slice(&self.slice[start..self.index]); - self.index += 1; - return result(self, scratch).map(Reference::Copied); - } - } - b'\\' => { - scratch.extend_from_slice(&self.slice[start..self.index]); - self.index += 1; - tri!(parse_escape(self, validate, scratch)); - start = self.index; - } - _ => { - self.index += 1; - if validate { - return error(self, ErrorCode::ControlCharacterWhileParsingString); - } - } - } - } - } -} - -impl<'a> private::Sealed for SliceRead<'a> {} - -impl<'a> Read<'a> for SliceRead<'a> { - #[inline] - fn next(&mut self) -> Result<Option<u8>> { - // `Ok(self.slice.get(self.index).map(|ch| { self.index += 1; *ch }))` - // is about 10% slower. - Ok(if self.index < self.slice.len() { - let ch = self.slice[self.index]; - self.index += 1; - Some(ch) - } else { - None - }) - } - - #[inline] - fn peek(&mut self) -> Result<Option<u8>> { - // `Ok(self.slice.get(self.index).map(|ch| *ch))` is about 10% slower - // for some reason. - Ok(if self.index < self.slice.len() { - Some(self.slice[self.index]) - } else { - None - }) - } - - #[inline] - fn discard(&mut self) { - self.index += 1; - } - - fn position(&self) -> Position { - self.position_of_index(self.index) - } - - fn peek_position(&self) -> Position { - // Cap it at slice.len() just in case the most recent call was next() - // and it returned the last byte. - self.position_of_index(cmp::min(self.slice.len(), self.index + 1)) - } - - fn byte_offset(&self) -> usize { - self.index - } - - fn parse_str<'s>(&'s mut self, scratch: &'s mut Vec<u8>) -> Result<Reference<'a, 's, str>> { - self.parse_str_bytes(scratch, true, as_str) - } - - fn parse_str_raw<'s>( - &'s mut self, - scratch: &'s mut Vec<u8>, - ) -> Result<Reference<'a, 's, [u8]>> { - self.parse_str_bytes(scratch, false, |_, bytes| Ok(bytes)) - } - - fn ignore_str(&mut self) -> Result<()> { - loop { - while self.index < self.slice.len() && !ESCAPE[self.slice[self.index] as usize] { - self.index += 1; - } - if self.index == self.slice.len() { - return error(self, ErrorCode::EofWhileParsingString); - } - match self.slice[self.index] { - b'"' => { - self.index += 1; - return Ok(()); - } - b'\\' => { - self.index += 1; - tri!(ignore_escape(self)); - } - _ => { - return error(self, ErrorCode::ControlCharacterWhileParsingString); - } - } - } - } - - fn decode_hex_escape(&mut self) -> Result<u16> { - if self.index + 4 > self.slice.len() { - self.index = self.slice.len(); - return error(self, ErrorCode::EofWhileParsingString); - } - - let mut n = 0; - for _ in 0..4 { - let ch = decode_hex_val(self.slice[self.index]); - self.index += 1; - match ch { - None => return error(self, ErrorCode::InvalidEscape), - Some(val) => { - n = (n << 4) + val; - } - } - } - Ok(n) - } - - #[cfg(feature = "raw_value")] - fn begin_raw_buffering(&mut self) { - self.raw_buffering_start_index = self.index; - } - - #[cfg(feature = "raw_value")] - fn end_raw_buffering<V>(&mut self, visitor: V) -> Result<V::Value> - where - V: Visitor<'a>, - { - let raw = &self.slice[self.raw_buffering_start_index..self.index]; - let raw = match str::from_utf8(raw) { - Ok(raw) => raw, - Err(_) => return error(self, ErrorCode::InvalidUnicodeCodePoint), - }; - visitor.visit_map(BorrowedRawDeserializer { - raw_value: Some(raw), - }) - } - - const should_early_return_if_failed: bool = false; - - #[inline] - #[cold] - fn set_failed(&mut self, _failed: &mut bool) { - self.slice = &self.slice[..self.index]; - } -} - -////////////////////////////////////////////////////////////////////////////// - -impl<'a> StrRead<'a> { - /// Create a JSON input source to read from a UTF-8 string. - pub fn new(s: &'a str) -> Self { - StrRead { - delegate: SliceRead::new(s.as_bytes()), - #[cfg(feature = "raw_value")] - data: s, - } - } -} - -impl<'a> private::Sealed for StrRead<'a> {} - -impl<'a> Read<'a> for StrRead<'a> { - #[inline] - fn next(&mut self) -> Result<Option<u8>> { - self.delegate.next() - } - - #[inline] - fn peek(&mut self) -> Result<Option<u8>> { - self.delegate.peek() - } - - #[inline] - fn discard(&mut self) { - self.delegate.discard(); - } - - fn position(&self) -> Position { - self.delegate.position() - } - - fn peek_position(&self) -> Position { - self.delegate.peek_position() - } - - fn byte_offset(&self) -> usize { - self.delegate.byte_offset() - } - - fn parse_str<'s>(&'s mut self, scratch: &'s mut Vec<u8>) -> Result<Reference<'a, 's, str>> { - self.delegate.parse_str_bytes(scratch, true, |_, bytes| { - // The deserialization input came in as &str with a UTF-8 guarantee, - // and the \u-escapes are checked along the way, so don't need to - // check here. - Ok(unsafe { str::from_utf8_unchecked(bytes) }) - }) - } - - fn parse_str_raw<'s>( - &'s mut self, - scratch: &'s mut Vec<u8>, - ) -> Result<Reference<'a, 's, [u8]>> { - self.delegate.parse_str_raw(scratch) - } - - fn ignore_str(&mut self) -> Result<()> { - self.delegate.ignore_str() - } - - fn decode_hex_escape(&mut self) -> Result<u16> { - self.delegate.decode_hex_escape() - } - - #[cfg(feature = "raw_value")] - fn begin_raw_buffering(&mut self) { - self.delegate.begin_raw_buffering(); - } - - #[cfg(feature = "raw_value")] - fn end_raw_buffering<V>(&mut self, visitor: V) -> Result<V::Value> - where - V: Visitor<'a>, - { - let raw = &self.data[self.delegate.raw_buffering_start_index..self.delegate.index]; - visitor.visit_map(BorrowedRawDeserializer { - raw_value: Some(raw), - }) - } - - const should_early_return_if_failed: bool = false; - - #[inline] - #[cold] - fn set_failed(&mut self, failed: &mut bool) { - self.delegate.set_failed(failed); - } -} - -////////////////////////////////////////////////////////////////////////////// - -impl<'a, 'de, R> private::Sealed for &'a mut R where R: Read<'de> {} - -impl<'a, 'de, R> Read<'de> for &'a mut R -where - R: Read<'de>, -{ - fn next(&mut self) -> Result<Option<u8>> { - R::next(self) - } - - fn peek(&mut self) -> Result<Option<u8>> { - R::peek(self) - } - - fn discard(&mut self) { - R::discard(self); - } - - fn position(&self) -> Position { - R::position(self) - } - - fn peek_position(&self) -> Position { - R::peek_position(self) - } - - fn byte_offset(&self) -> usize { - R::byte_offset(self) - } - - fn parse_str<'s>(&'s mut self, scratch: &'s mut Vec<u8>) -> Result<Reference<'de, 's, str>> { - R::parse_str(self, scratch) - } - - fn parse_str_raw<'s>( - &'s mut self, - scratch: &'s mut Vec<u8>, - ) -> Result<Reference<'de, 's, [u8]>> { - R::parse_str_raw(self, scratch) - } - - fn ignore_str(&mut self) -> Result<()> { - R::ignore_str(self) - } - - fn decode_hex_escape(&mut self) -> Result<u16> { - R::decode_hex_escape(self) - } - - #[cfg(feature = "raw_value")] - fn begin_raw_buffering(&mut self) { - R::begin_raw_buffering(self); - } - - #[cfg(feature = "raw_value")] - fn end_raw_buffering<V>(&mut self, visitor: V) -> Result<V::Value> - where - V: Visitor<'de>, - { - R::end_raw_buffering(self, visitor) - } - - const should_early_return_if_failed: bool = R::should_early_return_if_failed; - - fn set_failed(&mut self, failed: &mut bool) { - R::set_failed(self, failed); - } -} - -////////////////////////////////////////////////////////////////////////////// - -/// Marker for whether StreamDeserializer can implement FusedIterator. -pub trait Fused: private::Sealed {} -impl<'a> Fused for SliceRead<'a> {} -impl<'a> Fused for StrRead<'a> {} - -// Lookup table of bytes that must be escaped. A value of true at index i means -// that byte i requires an escape sequence in the input. -static ESCAPE: [bool; 256] = { - const CT: bool = true; // control character \x00..=\x1F - const QU: bool = true; // quote \x22 - const BS: bool = true; // backslash \x5C - const __: bool = false; // allow unescaped - [ - // 1 2 3 4 5 6 7 8 9 A B C D E F - CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, // 0 - CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, CT, // 1 - __, __, QU, __, __, __, __, __, __, __, __, __, __, __, __, __, // 2 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 3 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 4 - __, __, __, __, __, __, __, __, __, __, __, __, BS, __, __, __, // 5 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 6 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 7 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 8 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 9 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // A - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // B - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // C - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // D - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // E - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // F - ] -}; - -fn next_or_eof<'de, R>(read: &mut R) -> Result<u8> -where - R: ?Sized + Read<'de>, -{ - match tri!(read.next()) { - Some(b) => Ok(b), - None => error(read, ErrorCode::EofWhileParsingString), - } -} - -fn peek_or_eof<'de, R>(read: &mut R) -> Result<u8> -where - R: ?Sized + Read<'de>, -{ - match tri!(read.peek()) { - Some(b) => Ok(b), - None => error(read, ErrorCode::EofWhileParsingString), - } -} - -fn error<'de, R, T>(read: &R, reason: ErrorCode) -> Result<T> -where - R: ?Sized + Read<'de>, -{ - let position = read.position(); - Err(Error::syntax(reason, position.line, position.column)) -} - -fn as_str<'de, 's, R: Read<'de>>(read: &R, slice: &'s [u8]) -> Result<&'s str> { - str::from_utf8(slice).or_else(|_| error(read, ErrorCode::InvalidUnicodeCodePoint)) -} - -/// Parses a JSON escape sequence and appends it into the scratch space. Assumes -/// the previous byte read was a backslash. -fn parse_escape<'de, R: Read<'de>>( - read: &mut R, - validate: bool, - scratch: &mut Vec<u8>, -) -> Result<()> { - let ch = tri!(next_or_eof(read)); - - match ch { - b'"' => scratch.push(b'"'), - b'\\' => scratch.push(b'\\'), - b'/' => scratch.push(b'/'), - b'b' => scratch.push(b'\x08'), - b'f' => scratch.push(b'\x0c'), - b'n' => scratch.push(b'\n'), - b'r' => scratch.push(b'\r'), - b't' => scratch.push(b'\t'), - b'u' => { - fn encode_surrogate(scratch: &mut Vec<u8>, n: u16) { - scratch.extend_from_slice(&[ - (n >> 12 & 0b0000_1111) as u8 | 0b1110_0000, - (n >> 6 & 0b0011_1111) as u8 | 0b1000_0000, - (n & 0b0011_1111) as u8 | 0b1000_0000, - ]); - } - - let c = match tri!(read.decode_hex_escape()) { - n @ 0xDC00..=0xDFFF => { - return if validate { - error(read, ErrorCode::LoneLeadingSurrogateInHexEscape) - } else { - encode_surrogate(scratch, n); - Ok(()) - }; - } - - // Non-BMP characters are encoded as a sequence of two hex - // escapes, representing UTF-16 surrogates. If deserializing a - // utf-8 string the surrogates are required to be paired, - // whereas deserializing a byte string accepts lone surrogates. - n1 @ 0xD800..=0xDBFF => { - if tri!(peek_or_eof(read)) == b'\\' { - read.discard(); - } else { - return if validate { - read.discard(); - error(read, ErrorCode::UnexpectedEndOfHexEscape) - } else { - encode_surrogate(scratch, n1); - Ok(()) - }; - } - - if tri!(peek_or_eof(read)) == b'u' { - read.discard(); - } else { - return if validate { - read.discard(); - error(read, ErrorCode::UnexpectedEndOfHexEscape) - } else { - encode_surrogate(scratch, n1); - // The \ prior to this byte started an escape sequence, - // so we need to parse that now. This recursive call - // does not blow the stack on malicious input because - // the escape is not \u, so it will be handled by one - // of the easy nonrecursive cases. - parse_escape(read, validate, scratch) - }; - } - - let n2 = tri!(read.decode_hex_escape()); - - if n2 < 0xDC00 || n2 > 0xDFFF { - return error(read, ErrorCode::LoneLeadingSurrogateInHexEscape); - } - - let n = (((n1 - 0xD800) as u32) << 10 | (n2 - 0xDC00) as u32) + 0x1_0000; - - match char::from_u32(n) { - Some(c) => c, - None => { - return error(read, ErrorCode::InvalidUnicodeCodePoint); - } - } - } - - // Every u16 outside of the surrogate ranges above is guaranteed - // to be a legal char. - n => char::from_u32(n as u32).unwrap(), - }; - - scratch.extend_from_slice(c.encode_utf8(&mut [0_u8; 4]).as_bytes()); - } - _ => { - return error(read, ErrorCode::InvalidEscape); - } - } - - Ok(()) -} - -/// Parses a JSON escape sequence and discards the value. Assumes the previous -/// byte read was a backslash. -fn ignore_escape<'de, R>(read: &mut R) -> Result<()> -where - R: ?Sized + Read<'de>, -{ - let ch = tri!(next_or_eof(read)); - - match ch { - b'"' | b'\\' | b'/' | b'b' | b'f' | b'n' | b'r' | b't' => {} - b'u' => { - // At this point we don't care if the codepoint is valid. We just - // want to consume it. We don't actually know what is valid or not - // at this point, because that depends on if this string will - // ultimately be parsed into a string or a byte buffer in the "real" - // parse. - - tri!(read.decode_hex_escape()); - } - _ => { - return error(read, ErrorCode::InvalidEscape); - } - } - - Ok(()) -} - -static HEX: [u8; 256] = { - const __: u8 = 255; // not a hex digit - [ - // 1 2 3 4 5 6 7 8 9 A B C D E F - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 0 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 1 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 2 - 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, __, __, __, __, __, __, // 3 - __, 10, 11, 12, 13, 14, 15, __, __, __, __, __, __, __, __, __, // 4 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 5 - __, 10, 11, 12, 13, 14, 15, __, __, __, __, __, __, __, __, __, // 6 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 7 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 8 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // 9 - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // A - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // B - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // C - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // D - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // E - __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, // F - ] -}; - -fn decode_hex_val(val: u8) -> Option<u16> { - let n = HEX[val as usize] as u16; - if n == 255 { - None - } else { - Some(n) - } -} |