diff options
Diffstat (limited to 'third_party/rust/tokio-0.1.22/src/codec')
| -rw-r--r-- | third_party/rust/tokio-0.1.22/src/codec/length_delimited.rs | 982 | ||||
| -rw-r--r-- | third_party/rust/tokio-0.1.22/src/codec/mod.rs | 19 |
2 files changed, 1001 insertions, 0 deletions
diff --git a/third_party/rust/tokio-0.1.22/src/codec/length_delimited.rs b/third_party/rust/tokio-0.1.22/src/codec/length_delimited.rs new file mode 100644 index 0000000000..87393982b0 --- /dev/null +++ b/third_party/rust/tokio-0.1.22/src/codec/length_delimited.rs @@ -0,0 +1,982 @@ +//! Frame a stream of bytes based on a length prefix +//! +//! Many protocols delimit their frames by prefacing frame data with a +//! frame head that specifies the length of the frame. The +//! `length_delimited` module provides utilities for handling the length +//! based framing. This allows the consumer to work with entire frames +//! without having to worry about buffering or other framing logic. +//! +//! # Getting started +//! +//! If implementing a protocol from scratch, using length delimited framing +//! is an easy way to get started. [`LengthDelimitedCodec::new()`] will +//! return a length delimited codec using default configuration values. +//! This can then be used to construct a framer to adapt a full-duplex +//! byte stream into a stream of frames. +//! +//! ``` +//! # extern crate tokio; +//! use tokio::io::{AsyncRead, AsyncWrite}; +//! use tokio::codec::*; +//! +//! fn bind_transport<T: AsyncRead + AsyncWrite>(io: T) +//! -> Framed<T, LengthDelimitedCodec> +//! { +//! Framed::new(io, LengthDelimitedCodec::new()) +//! } +//! # pub fn main() {} +//! ``` +//! +//! The returned transport implements `Sink + Stream` for `BytesMut`. It +//! encodes the frame with a big-endian `u32` header denoting the frame +//! payload length: +//! +//! ```text +//! +----------+--------------------------------+ +//! | len: u32 | frame payload | +//! +----------+--------------------------------+ +//! ``` +//! +//! Specifically, given the following: +//! +//! ``` +//! # extern crate tokio; +//! # extern crate bytes; +//! # extern crate futures; +//! # +//! use tokio::io::{AsyncRead, AsyncWrite}; +//! use tokio::codec::*; +//! use bytes::Bytes; +//! use futures::{Sink, Future}; +//! +//! fn write_frame<T: AsyncRead + AsyncWrite>(io: T) -> Result<(), Box<std::error::Error>> { +//! let mut transport = Framed::new(io, LengthDelimitedCodec::new()); +//! let frame = Bytes::from("hello world"); +//! +//! transport.send(frame).wait()?; +//! Ok(()) +//! } +//! # +//! # pub fn main() {} +//! ``` +//! +//! The encoded frame will look like this: +//! +//! ```text +//! +---- len: u32 ----+---- data ----+ +//! | \x00\x00\x00\x0b | hello world | +//! +------------------+--------------+ +//! ``` +//! +//! # Decoding +//! +//! [`FramedRead`] adapts an [`AsyncRead`] into a `Stream` of [`BytesMut`], +//! such that each yielded [`BytesMut`] value contains the contents of an +//! entire frame. There are many configuration parameters enabling +//! [`FramedRead`] to handle a wide range of protocols. Here are some +//! examples that will cover the various options at a high level. +//! +//! ## Example 1 +//! +//! The following will parse a `u16` length field at offset 0, including the +//! frame head in the yielded `BytesMut`. +//! +//! ``` +//! # extern crate tokio; +//! # use tokio::io::AsyncRead; +//! # use tokio::codec::length_delimited; +//! # fn bind_read<T: AsyncRead>(io: T) { +//! length_delimited::Builder::new() +//! .length_field_offset(0) // default value +//! .length_field_length(2) +//! .length_adjustment(0) // default value +//! .num_skip(0) // Do not strip frame header +//! .new_read(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! The following frame will be decoded as such: +//! +//! ```text +//! INPUT DECODED +//! +-- len ---+--- Payload ---+ +-- len ---+--- Payload ---+ +//! | \x00\x0B | Hello world | --> | \x00\x0B | Hello world | +//! +----------+---------------+ +----------+---------------+ +//! ``` +//! +//! The value of the length field is 11 (`\x0B`) which represents the length +//! of the payload, `hello world`. By default, [`FramedRead`] assumes that +//! the length field represents the number of bytes that **follows** the +//! length field. Thus, the entire frame has a length of 13: 2 bytes for the +//! frame head + 11 bytes for the payload. +//! +//! ## Example 2 +//! +//! The following will parse a `u16` length field at offset 0, omitting the +//! frame head in the yielded `BytesMut`. +//! +//! ``` +//! # extern crate tokio; +//! # use tokio::io::AsyncRead; +//! # use tokio::codec::length_delimited; +//! # fn bind_read<T: AsyncRead>(io: T) { +//! length_delimited::Builder::new() +//! .length_field_offset(0) // default value +//! .length_field_length(2) +//! .length_adjustment(0) // default value +//! // `num_skip` is not needed, the default is to skip +//! .new_read(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! The following frame will be decoded as such: +//! +//! ```text +//! INPUT DECODED +//! +-- len ---+--- Payload ---+ +--- Payload ---+ +//! | \x00\x0B | Hello world | --> | Hello world | +//! +----------+---------------+ +---------------+ +//! ``` +//! +//! This is similar to the first example, the only difference is that the +//! frame head is **not** included in the yielded `BytesMut` value. +//! +//! ## Example 3 +//! +//! The following will parse a `u16` length field at offset 0, including the +//! frame head in the yielded `BytesMut`. In this case, the length field +//! **includes** the frame head length. +//! +//! ``` +//! # extern crate tokio; +//! # use tokio::io::AsyncRead; +//! # use tokio::codec::length_delimited; +//! # fn bind_read<T: AsyncRead>(io: T) { +//! length_delimited::Builder::new() +//! .length_field_offset(0) // default value +//! .length_field_length(2) +//! .length_adjustment(-2) // size of head +//! .num_skip(0) +//! .new_read(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! The following frame will be decoded as such: +//! +//! ```text +//! INPUT DECODED +//! +-- len ---+--- Payload ---+ +-- len ---+--- Payload ---+ +//! | \x00\x0D | Hello world | --> | \x00\x0D | Hello world | +//! +----------+---------------+ +----------+---------------+ +//! ``` +//! +//! In most cases, the length field represents the length of the payload +//! only, as shown in the previous examples. However, in some protocols the +//! length field represents the length of the whole frame, including the +//! head. In such cases, we specify a negative `length_adjustment` to adjust +//! the value provided in the frame head to represent the payload length. +//! +//! ## Example 4 +//! +//! The following will parse a 3 byte length field at offset 0 in a 5 byte +//! frame head, including the frame head in the yielded `BytesMut`. +//! +//! ``` +//! # extern crate tokio; +//! # use tokio::io::AsyncRead; +//! # use tokio::codec::length_delimited; +//! # fn bind_read<T: AsyncRead>(io: T) { +//! length_delimited::Builder::new() +//! .length_field_offset(0) // default value +//! .length_field_length(3) +//! .length_adjustment(2) // remaining head +//! .num_skip(0) +//! .new_read(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! The following frame will be decoded as such: +//! +//! ```text +//! INPUT +//! +---- len -----+- head -+--- Payload ---+ +//! | \x00\x00\x0B | \xCAFE | Hello world | +//! +--------------+--------+---------------+ +//! +//! DECODED +//! +---- len -----+- head -+--- Payload ---+ +//! | \x00\x00\x0B | \xCAFE | Hello world | +//! +--------------+--------+---------------+ +//! ``` +//! +//! A more advanced example that shows a case where there is extra frame +//! head data between the length field and the payload. In such cases, it is +//! usually desirable to include the frame head as part of the yielded +//! `BytesMut`. This lets consumers of the length delimited framer to +//! process the frame head as needed. +//! +//! The positive `length_adjustment` value lets `FramedRead` factor in the +//! additional head into the frame length calculation. +//! +//! ## Example 5 +//! +//! The following will parse a `u16` length field at offset 1 of a 4 byte +//! frame head. The first byte and the length field will be omitted from the +//! yielded `BytesMut`, but the trailing 2 bytes of the frame head will be +//! included. +//! +//! ``` +//! # extern crate tokio; +//! # use tokio::io::AsyncRead; +//! # use tokio::codec::length_delimited; +//! # fn bind_read<T: AsyncRead>(io: T) { +//! length_delimited::Builder::new() +//! .length_field_offset(1) // length of hdr1 +//! .length_field_length(2) +//! .length_adjustment(1) // length of hdr2 +//! .num_skip(3) // length of hdr1 + LEN +//! .new_read(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! The following frame will be decoded as such: +//! +//! ```text +//! INPUT +//! +- hdr1 -+-- len ---+- hdr2 -+--- Payload ---+ +//! | \xCA | \x00\x0B | \xFE | Hello world | +//! +--------+----------+--------+---------------+ +//! +//! DECODED +//! +- hdr2 -+--- Payload ---+ +//! | \xFE | Hello world | +//! +--------+---------------+ +//! ``` +//! +//! The length field is situated in the middle of the frame head. In this +//! case, the first byte in the frame head could be a version or some other +//! identifier that is not needed for processing. On the other hand, the +//! second half of the head is needed. +//! +//! `length_field_offset` indicates how many bytes to skip before starting +//! to read the length field. `length_adjustment` is the number of bytes to +//! skip starting at the end of the length field. In this case, it is the +//! second half of the head. +//! +//! ## Example 6 +//! +//! The following will parse a `u16` length field at offset 1 of a 4 byte +//! frame head. The first byte and the length field will be omitted from the +//! yielded `BytesMut`, but the trailing 2 bytes of the frame head will be +//! included. In this case, the length field **includes** the frame head +//! length. +//! +//! ``` +//! # extern crate tokio; +//! # use tokio::io::AsyncRead; +//! # use tokio::codec::length_delimited; +//! # fn bind_read<T: AsyncRead>(io: T) { +//! length_delimited::Builder::new() +//! .length_field_offset(1) // length of hdr1 +//! .length_field_length(2) +//! .length_adjustment(-3) // length of hdr1 + LEN, negative +//! .num_skip(3) +//! .new_read(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! The following frame will be decoded as such: +//! +//! ```text +//! INPUT +//! +- hdr1 -+-- len ---+- hdr2 -+--- Payload ---+ +//! | \xCA | \x00\x0F | \xFE | Hello world | +//! +--------+----------+--------+---------------+ +//! +//! DECODED +//! +- hdr2 -+--- Payload ---+ +//! | \xFE | Hello world | +//! +--------+---------------+ +//! ``` +//! +//! Similar to the example above, the difference is that the length field +//! represents the length of the entire frame instead of just the payload. +//! The length of `hdr1` and `len` must be counted in `length_adjustment`. +//! Note that the length of `hdr2` does **not** need to be explicitly set +//! anywhere because it already is factored into the total frame length that +//! is read from the byte stream. +//! +//! # Encoding +//! +//! [`FramedWrite`] adapts an [`AsyncWrite`] into a `Sink` of [`BytesMut`], +//! such that each submitted [`BytesMut`] is prefaced by a length field. +//! There are fewer configuration options than [`FramedRead`]. Given +//! protocols that have more complex frame heads, an encoder should probably +//! be written by hand using [`Encoder`]. +//! +//! Here is a simple example, given a `FramedWrite` with the following +//! configuration: +//! +//! ``` +//! # extern crate tokio; +//! # extern crate bytes; +//! # use tokio::io::AsyncWrite; +//! # use tokio::codec::length_delimited; +//! # use bytes::BytesMut; +//! # fn write_frame<T: AsyncWrite>(io: T) { +//! # let _ = +//! length_delimited::Builder::new() +//! .length_field_length(2) +//! .new_write(io); +//! # } +//! # pub fn main() {} +//! ``` +//! +//! A payload of `hello world` will be encoded as: +//! +//! ```text +//! +- len: u16 -+---- data ----+ +//! | \x00\x0b | hello world | +//! +------------+--------------+ +//! ``` +//! +//! [`LengthDelimitedCodec::new()`]: struct.LengthDelimitedCodec.html#method.new +//! [`FramedRead`]: struct.FramedRead.html +//! [`FramedWrite`]: struct.FramedWrite.html +//! [`AsyncRead`]: ../../trait.AsyncRead.html +//! [`AsyncWrite`]: ../../trait.AsyncWrite.html +//! [`Encoder`]: ../trait.Encoder.html +//! [`BytesMut`]: https://docs.rs/bytes/0.4/bytes/struct.BytesMut.html + +use { + codec::{Decoder, Encoder, Framed, FramedRead, FramedWrite}, + io::{AsyncRead, AsyncWrite}, +}; + +use bytes::{Buf, BufMut, Bytes, BytesMut, IntoBuf}; + +use std::error::Error as StdError; +use std::io::{self, Cursor}; +use std::{cmp, fmt}; + +/// Configure length delimited `LengthDelimitedCodec`s. +/// +/// `Builder` enables constructing configured length delimited codecs. Note +/// that not all configuration settings apply to both encoding and decoding. See +/// the documentation for specific methods for more detail. +#[derive(Debug, Clone, Copy)] +pub struct Builder { + // Maximum frame length + max_frame_len: usize, + + // Number of bytes representing the field length + length_field_len: usize, + + // Number of bytes in the header before the length field + length_field_offset: usize, + + // Adjust the length specified in the header field by this amount + length_adjustment: isize, + + // Total number of bytes to skip before reading the payload, if not set, + // `length_field_len + length_field_offset` + num_skip: Option<usize>, + + // Length field byte order (little or big endian) + length_field_is_big_endian: bool, +} + +/// An error when the number of bytes read is more than max frame length. +pub struct FrameTooBig { + _priv: (), +} + +/// A codec for frames delimited by a frame head specifying their lengths. +/// +/// This allows the consumer to work with entire frames without having to worry +/// about buffering or other framing logic. +/// +/// See [module level] documentation for more detail. +/// +/// [module level]: index.html +#[derive(Debug)] +pub struct LengthDelimitedCodec { + // Configuration values + builder: Builder, + + // Read state + state: DecodeState, +} + +#[derive(Debug, Clone, Copy)] +enum DecodeState { + Head, + Data(usize), +} + +// ===== impl LengthDelimitedCodec ====== + +impl LengthDelimitedCodec { + /// Creates a new `LengthDelimitedCodec` with the default configuration values. + pub fn new() -> Self { + Self { + builder: Builder::new(), + state: DecodeState::Head, + } + } + + /// Returns the current max frame setting + /// + /// This is the largest size this codec will accept from the wire. Larger + /// frames will be rejected. + pub fn max_frame_length(&self) -> usize { + self.builder.max_frame_len + } + + /// Updates the max frame setting. + /// + /// The change takes effect the next time a frame is decoded. In other + /// words, if a frame is currently in process of being decoded with a frame + /// size greater than `val` but less than the max frame length in effect + /// before calling this function, then the frame will be allowed. + pub fn set_max_frame_length(&mut self, val: usize) { + self.builder.max_frame_length(val); + } + + fn decode_head(&mut self, src: &mut BytesMut) -> io::Result<Option<usize>> { + let head_len = self.builder.num_head_bytes(); + let field_len = self.builder.length_field_len; + + if src.len() < head_len { + // Not enough data + return Ok(None); + } + + let n = { + let mut src = Cursor::new(&mut *src); + + // Skip the required bytes + src.advance(self.builder.length_field_offset); + + // match endianess + let n = if self.builder.length_field_is_big_endian { + src.get_uint_be(field_len) + } else { + src.get_uint_le(field_len) + }; + + if n > self.builder.max_frame_len as u64 { + return Err(io::Error::new( + io::ErrorKind::InvalidData, + FrameTooBig { _priv: () }, + )); + } + + // The check above ensures there is no overflow + let n = n as usize; + + // Adjust `n` with bounds checking + let n = if self.builder.length_adjustment < 0 { + n.checked_sub(-self.builder.length_adjustment as usize) + } else { + n.checked_add(self.builder.length_adjustment as usize) + }; + + // Error handling + match n { + Some(n) => n, + None => { + return Err(io::Error::new( + io::ErrorKind::InvalidInput, + "provided length would overflow after adjustment", + )); + } + } + }; + + let num_skip = self.builder.get_num_skip(); + + if num_skip > 0 { + let _ = src.split_to(num_skip); + } + + // Ensure that the buffer has enough space to read the incoming + // payload + src.reserve(n); + + return Ok(Some(n)); + } + + fn decode_data(&self, n: usize, src: &mut BytesMut) -> io::Result<Option<BytesMut>> { + // At this point, the buffer has already had the required capacity + // reserved. All there is to do is read. + if src.len() < n { + return Ok(None); + } + + Ok(Some(src.split_to(n))) + } +} + +impl Decoder for LengthDelimitedCodec { + type Item = BytesMut; + type Error = io::Error; + + fn decode(&mut self, src: &mut BytesMut) -> io::Result<Option<BytesMut>> { + let n = match self.state { + DecodeState::Head => match self.decode_head(src)? { + Some(n) => { + self.state = DecodeState::Data(n); + n + } + None => return Ok(None), + }, + DecodeState::Data(n) => n, + }; + + match self.decode_data(n, src)? { + Some(data) => { + // Update the decode state + self.state = DecodeState::Head; + + // Make sure the buffer has enough space to read the next head + src.reserve(self.builder.num_head_bytes()); + + Ok(Some(data)) + } + None => Ok(None), + } + } +} + +impl Encoder for LengthDelimitedCodec { + type Item = Bytes; + type Error = io::Error; + + fn encode(&mut self, data: Bytes, dst: &mut BytesMut) -> Result<(), io::Error> { + let n = (&data).into_buf().remaining(); + + if n > self.builder.max_frame_len { + return Err(io::Error::new( + io::ErrorKind::InvalidInput, + FrameTooBig { _priv: () }, + )); + } + + // Adjust `n` with bounds checking + let n = if self.builder.length_adjustment < 0 { + n.checked_add(-self.builder.length_adjustment as usize) + } else { + n.checked_sub(self.builder.length_adjustment as usize) + }; + + let n = n.ok_or_else(|| { + io::Error::new( + io::ErrorKind::InvalidInput, + "provided length would overflow after adjustment", + ) + })?; + + // Reserve capacity in the destination buffer to fit the frame and + // length field (plus adjustment). + dst.reserve(self.builder.length_field_len + n); + + if self.builder.length_field_is_big_endian { + dst.put_uint_be(n as u64, self.builder.length_field_len); + } else { + dst.put_uint_le(n as u64, self.builder.length_field_len); + } + + // Write the frame to the buffer + dst.extend_from_slice(&data[..]); + + Ok(()) + } +} + +// ===== impl Builder ===== + +impl Builder { + /// Creates a new length delimited codec builder with default configuration + /// values. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .length_field_offset(0) + /// .length_field_length(2) + /// .length_adjustment(0) + /// .num_skip(0) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn new() -> Builder { + Builder { + // Default max frame length of 8MB + max_frame_len: 8 * 1_024 * 1_024, + + // Default byte length of 4 + length_field_len: 4, + + // Default to the header field being at the start of the header. + length_field_offset: 0, + + length_adjustment: 0, + + // Total number of bytes to skip before reading the payload, if not set, + // `length_field_len + length_field_offset` + num_skip: None, + + // Default to reading the length field in network (big) endian. + length_field_is_big_endian: true, + } + } + + /// Read the length field as a big endian integer + /// + /// This is the default setting. + /// + /// This configuration option applies to both encoding and decoding. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .big_endian() + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn big_endian(&mut self) -> &mut Self { + self.length_field_is_big_endian = true; + self + } + + /// Read the length field as a little endian integer + /// + /// The default setting is big endian. + /// + /// This configuration option applies to both encoding and decoding. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .little_endian() + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn little_endian(&mut self) -> &mut Self { + self.length_field_is_big_endian = false; + self + } + + /// Read the length field as a native endian integer + /// + /// The default setting is big endian. + /// + /// This configuration option applies to both encoding and decoding. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .native_endian() + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn native_endian(&mut self) -> &mut Self { + if cfg!(target_endian = "big") { + self.big_endian() + } else { + self.little_endian() + } + } + + /// Sets the max frame length + /// + /// This configuration option applies to both encoding and decoding. The + /// default value is 8MB. + /// + /// When decoding, the length field read from the byte stream is checked + /// against this setting **before** any adjustments are applied. When + /// encoding, the length of the submitted payload is checked against this + /// setting. + /// + /// When frames exceed the max length, an `io::Error` with the custom value + /// of the `FrameTooBig` type will be returned. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .max_frame_length(8 * 1024) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn max_frame_length(&mut self, val: usize) -> &mut Self { + self.max_frame_len = val; + self + } + + /// Sets the number of bytes used to represent the length field + /// + /// The default value is `4`. The max value is `8`. + /// + /// This configuration option applies to both encoding and decoding. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .length_field_length(4) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn length_field_length(&mut self, val: usize) -> &mut Self { + assert!(val > 0 && val <= 8, "invalid length field length"); + self.length_field_len = val; + self + } + + /// Sets the number of bytes in the header before the length field + /// + /// This configuration option only applies to decoding. + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .length_field_offset(1) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn length_field_offset(&mut self, val: usize) -> &mut Self { + self.length_field_offset = val; + self + } + + /// Delta between the payload length specified in the header and the real + /// payload length + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .length_adjustment(-2) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn length_adjustment(&mut self, val: isize) -> &mut Self { + self.length_adjustment = val; + self + } + + /// Sets the number of bytes to skip before reading the payload + /// + /// Default value is `length_field_len + length_field_offset` + /// + /// This configuration option only applies to decoding + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .num_skip(4) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn num_skip(&mut self, val: usize) -> &mut Self { + self.num_skip = Some(val); + self + } + + /// Create a configured length delimited `LengthDelimitedCodec` + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// # pub fn main() { + /// Builder::new() + /// .length_field_offset(0) + /// .length_field_length(2) + /// .length_adjustment(0) + /// .num_skip(0) + /// .new_codec(); + /// # } + /// ``` + pub fn new_codec(&self) -> LengthDelimitedCodec { + LengthDelimitedCodec { + builder: *self, + state: DecodeState::Head, + } + } + + /// Create a configured length delimited `FramedRead` + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # use tokio::io::AsyncRead; + /// use tokio::codec::length_delimited::Builder; + /// + /// # fn bind_read<T: AsyncRead>(io: T) { + /// Builder::new() + /// .length_field_offset(0) + /// .length_field_length(2) + /// .length_adjustment(0) + /// .num_skip(0) + /// .new_read(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn new_read<T>(&self, upstream: T) -> FramedRead<T, LengthDelimitedCodec> + where + T: AsyncRead, + { + FramedRead::new(upstream, self.new_codec()) + } + + /// Create a configured length delimited `FramedWrite` + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # extern crate bytes; + /// # use tokio::io::AsyncWrite; + /// # use tokio::codec::length_delimited; + /// # use bytes::BytesMut; + /// # fn write_frame<T: AsyncWrite>(io: T) { + /// length_delimited::Builder::new() + /// .length_field_length(2) + /// .new_write(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn new_write<T>(&self, inner: T) -> FramedWrite<T, LengthDelimitedCodec> + where + T: AsyncWrite, + { + FramedWrite::new(inner, self.new_codec()) + } + + /// Create a configured length delimited `Framed` + /// + /// # Examples + /// + /// ``` + /// # extern crate tokio; + /// # extern crate bytes; + /// # use tokio::io::{AsyncRead, AsyncWrite}; + /// # use tokio::codec::length_delimited; + /// # use bytes::BytesMut; + /// # fn write_frame<T: AsyncRead + AsyncWrite>(io: T) { + /// # let _ = + /// length_delimited::Builder::new() + /// .length_field_length(2) + /// .new_framed(io); + /// # } + /// # pub fn main() {} + /// ``` + pub fn new_framed<T>(&self, inner: T) -> Framed<T, LengthDelimitedCodec> + where + T: AsyncRead + AsyncWrite, + { + Framed::new(inner, self.new_codec()) + } + + fn num_head_bytes(&self) -> usize { + let num = self.length_field_offset + self.length_field_len; + cmp::max(num, self.num_skip.unwrap_or(0)) + } + + fn get_num_skip(&self) -> usize { + self.num_skip + .unwrap_or(self.length_field_offset + self.length_field_len) + } +} + +// ===== impl FrameTooBig ===== + +impl fmt::Debug for FrameTooBig { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + f.debug_struct("FrameTooBig").finish() + } +} + +impl fmt::Display for FrameTooBig { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + f.write_str(self.description()) + } +} + +impl StdError for FrameTooBig { + fn description(&self) -> &str { + "frame size too big" + } +} diff --git a/third_party/rust/tokio-0.1.22/src/codec/mod.rs b/third_party/rust/tokio-0.1.22/src/codec/mod.rs new file mode 100644 index 0000000000..b6a3bbcb0d --- /dev/null +++ b/third_party/rust/tokio-0.1.22/src/codec/mod.rs @@ -0,0 +1,19 @@ +//! Utilities for encoding and decoding frames. +//! +//! Contains adapters to go from streams of bytes, [`AsyncRead`] and +//! [`AsyncWrite`], to framed streams implementing [`Sink`] and [`Stream`]. +//! Framed streams are also known as [transports]. +//! +//! [`AsyncRead`]: ../io/trait.AsyncRead.html +//! [`AsyncWrite`]: ../io/trait.AsyncWrite.html +//! [`Sink`]: https://docs.rs/futures/0.1/futures/sink/trait.Sink.html +//! [`Stream`]: https://docs.rs/futures/0.1/futures/stream/trait.Stream.html +//! [transports]: https://tokio.rs/docs/going-deeper/frames/ + +pub use tokio_codec::{ + BytesCodec, Decoder, Encoder, Framed, FramedParts, FramedRead, FramedWrite, LinesCodec, +}; + +pub mod length_delimited; + +pub use self::length_delimited::LengthDelimitedCodec; |