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|
use std::io;
use std::cmp;
use super::*;
/// Limits the amount of data that can be read from a
/// `BufferedReader`.
pub struct Limitor<T: BufferedReader<C>, C> {
reader: T,
limit: u64,
cookie: C,
}
impl<T: BufferedReader<C>, C> fmt::Display for Limitor<T, C> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Limitor ({} bytes)", self.limit)
}
}
impl<T: BufferedReader<C>, C> fmt::Debug for Limitor<T, C> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("Limitor")
.field("limit", &self.limit)
.field("reader", &self.reader)
.finish()
}
}
impl<T: BufferedReader<()>> Limitor<T, ()> {
/// Instantiates a new limitor.
///
/// `reader` is the source to wrap. `limit` is the maximum number
/// of bytes that can be read from the source.
pub fn new(reader: T, limit: u64) -> Self {
Self::with_cookie(reader, limit, ())
}
}
impl<T: BufferedReader<C>, C> Limitor<T, C> {
/// Like `new()`, but sets a cookie.
///
/// The cookie can be retrieved using the `cookie_ref` and
/// `cookie_mut` methods, and set using the `cookie_set` method.
pub fn with_cookie(reader: T, limit: u64, cookie: C)
-> Limitor<T, C> {
Limitor {
reader: reader,
limit: limit,
cookie: cookie,
}
}
}
impl<T: BufferedReader<C>, C> io::Read for Limitor<T, C> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
let len = cmp::min(self.limit, buf.len() as u64) as usize;
let result = self.reader.read(&mut buf[0..len]);
if let Ok(amount) = result {
self.limit -= amount as u64;
}
result
}
}
impl<T: BufferedReader<C>, C> BufferedReader<C> for Limitor<T, C> {
fn buffer(&self) -> &[u8] {
let buf = self.reader.buffer();
&buf[..cmp::min(buf.len(),
cmp::min(std::usize::MAX as u64,
self.limit) as usize)]
}
/// Return the buffer. Ensure that it contains at least `amount`
/// bytes.
fn data(&mut self, amount: usize) -> Result<&[u8], io::Error> {
let amount = cmp::min(amount as u64, self.limit) as usize;
let result = self.reader.data(amount);
match result {
Ok(ref buffer) =>
if buffer.len() as u64 > self.limit {
return Ok(&buffer[0..self.limit as usize]);
} else {
return Ok(buffer);
},
Err(err) => return Err(err),
}
}
fn consume(&mut self, amount: usize) -> &[u8] {
assert!(amount as u64 <= self.limit);
self.limit -= amount as u64;
let data = self.reader.consume(amount);
return &data[..cmp::min(self.limit + amount as u64, data.len() as u64) as usize];
}
fn data_consume(&mut self, amount: usize) -> Result<&[u8], io::Error> {
let amount = cmp::min(amount as u64, self.limit) as usize;
let result = self.reader.data_consume(amount);
if let Ok(ref buffer) = result {
let amount = cmp::min(amount, buffer.len());
self.limit -= amount as u64;
return Ok(&buffer[
..cmp::min(buffer.len() as u64, self.limit + amount as u64) as usize]);
}
return result;
}
fn data_consume_hard(&mut self, amount: usize) -> Result<&[u8], io::Error> {
if amount as u64 > self.limit {
return Err(Error::new(ErrorKind::UnexpectedEof, "EOF"));
}
let result = self.reader.data_consume_hard(amount);
if let Ok(ref buffer) = result {
let amount = cmp::min(amount, buffer.len());
self.limit -= amount as u64;
return Ok(&buffer[
..cmp::min(buffer.len() as u64, self.limit + amount as u64) as usize]);
}
return result;
}
fn consummated(&mut self) -> bool {
self.limit == 0
}
fn get_mut(&mut self) -> Option<&mut dyn BufferedReader<C>> {
Some(&mut self.reader)
}
fn get_ref(&self) -> Option<&dyn BufferedReader<C>> {
Some(&self.reader)
}
fn into_inner<'b>(self: Box<Self>) -> Option<Box<dyn BufferedReader<C> + 'b>>
where Self: 'b {
Some
|