101 lines
3.0 KiB
Rust
101 lines
3.0 KiB
Rust
use bytes::{
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Buf,
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BufMut,
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BytesMut
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};
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use futures::{
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Async,
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stream::Stream
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};
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use crate::ebml::{
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EbmlEventSource,
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FromEbml
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};
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use crate::error::WebmetroError;
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pub struct EbmlStreamingParser<S> {
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stream: S,
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buffer: BytesMut,
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buffer_size_limit: Option<usize>,
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last_read: usize
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}
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impl<S> EbmlStreamingParser<S> {
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/// add a "soft" buffer size limit; if the input buffer exceeds this size,
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/// error the stream instead of resuming. It's still possible for the buffer
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/// to exceed this size *after* a fill, so ensure input sizes are reasonable.
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pub fn with_soft_limit(mut self, limit: usize) -> Self {
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self.buffer_size_limit = Some(limit);
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self
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}
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}
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pub trait StreamEbml where Self: Sized + Stream, Self::Item: Buf {
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fn parse_ebml(self) -> EbmlStreamingParser<Self> {
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EbmlStreamingParser {
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stream: self,
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buffer: BytesMut::new(),
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buffer_size_limit: None,
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last_read: 0
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}
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}
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}
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impl<I: Buf, S: Stream<Item = I, Error = WebmetroError>> StreamEbml for S {}
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impl<I: Buf, S: Stream<Item = I, Error = WebmetroError>> EbmlStreamingParser<S> {
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pub fn poll_event<'a, T: FromEbml<'a>>(&'a mut self) -> Result<Async<Option<T>>, WebmetroError> {
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// release buffer from previous event
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self.buffer.advance(self.last_read);
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self.last_read = 0;
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loop {
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match T::check_space(&self.buffer) {
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Ok(None) => {
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// need to refill buffer, below
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},
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other => return other.map_err(WebmetroError::EbmlError).and_then(move |_| {
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match T::decode_element(&self.buffer) {
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Err(err) => Err(WebmetroError::EbmlError(err)),
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Ok(None) => panic!("Buffer was supposed to have enough data to parse element, somehow did not."),
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Ok(Some((element, element_size))) => {
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self.last_read = element_size;
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Ok(Async::Ready(Some(element)))
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}
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}
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})
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}
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if let Some(limit) = self.buffer_size_limit {
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if limit <= self.buffer.len() {
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return Err(WebmetroError::ResourcesExceeded);
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}
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}
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match self.stream.poll() {
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Ok(Async::Ready(Some(buf))) => {
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self.buffer.reserve(buf.remaining());
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self.buffer.put(buf);
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// ok can retry decoding now
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},
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other => return other.map(|async_status| async_status.map(|_| None))
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}
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}
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}
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}
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impl<I: Buf, S: Stream<Item = I, Error = WebmetroError>> EbmlEventSource for EbmlStreamingParser<S> {
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type Error = WebmetroError;
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fn poll_event<'a, T: FromEbml<'a>>(&'a mut self) -> Result<Async<Option<T>>, WebmetroError> {
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return EbmlStreamingParser::poll_event(self);
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}
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}
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#[cfg(test)]
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mod tests {
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//#[test]
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}
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