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use crate::frame::{util, Error, Frame, Head, Kind, StreamId};
use bytes::{Buf, BufMut, Bytes};
use std::fmt;
/// Data frame
///
/// Data frames convey arbitrary, variable-length sequences of octets associated
/// with a stream. One or more DATA frames are used, for instance, to carry HTTP
/// request or response payloads.
#[derive(Eq, PartialEq)]
pub struct Data<T = Bytes> {
stream_id: StreamId,
data: T,
flags: DataFlags,
pad_len: Option<u8>,
}
#[derive(Copy, Clone, Default, Eq, PartialEq)]
struct DataFlags(u8);
const END_STREAM: u8 = 0x1;
const PADDED: u8 = 0x8;
const ALL: u8 = END_STREAM | PADDED;
impl<T> Data<T> {
/// Creates a new DATA frame.
pub fn new(stream_id: StreamId, payload: T) -> Self {
assert!(!stream_id.is_zero());
Data {
stream_id,
data: payload,
flags: DataFlags::default(),
pad_len: None,
}
}
/// Returns the stream identifier that this frame is associated with.
///
/// This cannot be a zero stream identifier.
pub fn stream_id(&self) -> StreamId {
self.stream_id
}
/// Gets the value of the `END_STREAM` flag for this frame.
///
/// If true, this frame is the last that the endpoint will send for the
/// identified stream.
///
/// Setting this flag causes the stream to enter one of the "half-closed"
/// states or the "closed" state (Section 5.1).
pub fn is_end_stream(&self) -> bool {
self.flags.is_end_stream()
}
/// Sets the value for the `END_STREAM` flag on this frame.
pub fn set_end_stream(&mut self, val: bool) {
if val {
self.flags.set_end_stream();
} else {
self.flags.unset_end_stream();
}
}
/// Returns whether the `PADDED` flag is set on this frame.
#[cfg(feature = "unstable")]
pub fn is_padded(&self) -> bool {
self.flags.is_padded()
}
/// Sets the value for the `PADDED` flag on this frame.
#[cfg(feature = "unstable")]
pub fn set_padded(&mut self) {
self.flags.set_padded();
}
/// Returns a reference to this frame's payload.
///
/// This does **not** include any padding that might have been originally
/// included.
pub fn payload(&self) -> &T {
&self.data
}
/// Returns a mutable reference to this frame's payload.
///
/// This does **not** include any padding that might have been originally
/// included.
pub fn payload_mut(&mut self) -> &mut T {
&mut self.data
}
/// Consumes `self` and returns the frame's payload.
///
/// This does **not** include any padding that might have been originally
/// included.
pub fn into_payload(self) -> T {
self.data
}
pub(crate) fn head(&self) -> Head {
Head::new(Kind::Data, self.flags.into(), self.stream_id)
}
pub(crate) fn map<F, U>(self, f: F) -> Data<U>
where
F: FnOnce(T) -> U,
{
Data {
stream_id: self.stream_id,
data: f(self.data),
flags: self.flags,
pad_len: self.pad_len,
}
}
}
impl Data<Bytes> {
pub(crate) fn load(head: Head, mut payload: Bytes) -> Result<Self, Error> {
let flags = DataFlags::load(head.flag());
// The stream identifier must not be zero
if head.stream_id().is_zero() {
return Err(Error::InvalidStreamId);
}
let pad_len = if flags.is_padded() {
let len = util::strip_padding(&mut payload)?;
Some(len)
} else {
None
};
Ok(Data {
stream_id: head.stream_id(),
data: payload,
flags,
pad_len,
})
}
}
impl<T: Buf> Data<T> {
/// Encode the data frame into the `dst` buffer.
///
/// # Panics
///
/// Panics if `dst` cannot contain the data frame.
pub(crate) fn encode_chunk<U: BufMut>(&mut self, dst: &mut U) {
let len = self.data.remaining();
assert!(dst.remaining_mut() >= len);
self.head().encode(len, dst);
dst.put(&mut self.data);
}
}
impl<T> From<Data<T>> for Frame<T> {
fn from(src: Data<T>) -> Self {
Frame::Data(src)
}
}
impl<T> fmt::Debug for Data<T> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let mut f = fmt.debug_struct("Data");
f.field("stream_id", &self.stream_id);
if !self.flags.is_empty() {
f.field("flags", &self.flags);
}
if let Some(ref pad_len) = self.pad_len {
f.field("pad_len", pad_len);
}
// `data` bytes purposefully excluded
f.finish()
}
}
// ===== impl DataFlags =====
impl DataFlags {
fn load(bits: u8) -> DataFlags {
DataFlags(bits & ALL)
}
fn is_empty(&self) -> bool {
self.0 == 0
}
fn is_end_stream(&self) -> bool {
self.0 & END_STREAM == END_STREAM
}
fn set_end_stream(&mut self) {
self.0 |= END_STREAM
}
fn unset_end_stream(&mut self) {
self.0 &= !END_STREAM
}
fn is_padded(&self) -> bool {
self.0 & PADDED == PADDED
}
#[cfg(feature = "unstable")]
fn set_padded(&mut self) {
self.0 |= PADDED
}
}
impl From<DataFlags> for u8 {
fn from(src: DataFlags) -> u8 {
src.0
}
}
impl fmt::Debug for DataFlags {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
util::debug_flags(fmt, self.0)
.flag_if(self.is_end_stream(), "END_STREAM")
.flag_if(self.is_padded(), "PADDED")
.finish()
}
}