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Export all headers from MultiGzDecoder #348

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Export all headers from MultiGzDecoder #348

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16 changes: 12 additions & 4 deletions src/gz/bufread.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -205,6 +205,7 @@ pub struct GzDecoder<R> {
state: GzState,
reader: CrcReader<deflate::bufread::DeflateDecoder<R>>,
multi: bool,
headers: Vec<GzHeader>,
}

#[derive(Debug)]
Expand Down Expand Up @@ -240,6 +241,7 @@ impl<R: BufRead> GzDecoder<R> {
state,
reader: CrcReader::new(deflate::bufread::DeflateDecoder::new(r)),
multi: false,
headers: Vec::new(),
}
}

Expand Down Expand Up @@ -284,6 +286,7 @@ impl<R: BufRead> Read for GzDecoder<R> {
state,
reader,
multi,
headers,
} = self;

loop {
Expand Down Expand Up @@ -366,9 +369,10 @@ impl<R: BufRead> Read for GzDecoder<R> {
return Err(err);
}
};
headers.push(header);
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Even if performance wouldn't be an issue, these headers contain a few allocations themselves and I can imagine that archives with millions of members would now see a problem with memory consumption where previously they would not have an issue.

In order to prevent regression in that regard, I think this feature must be opt-in, controllable from the MutliGzDecoder which already sets the multi flag.


if is_eof {
GzState::End(Some(header))
GzState::End(None)
} else {
reader.reset();
reader.get_mut().reset_data();
Expand Down Expand Up @@ -449,9 +453,13 @@ impl<R: BufRead> MultiGzDecoder<R> {
}

impl<R> MultiGzDecoder<R> {
/// Returns the current header associated with this stream, if it's valid
pub fn header(&self) -> Option<&GzHeader> {
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I think there is no need to make this a breaking change by removing the single-header access method. It can live side-by-side with the headers() method.

self.0.header()
/// Returns the headers processed so far
pub fn headers(&self) -> Vec<&GzHeader> {
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This could be allocation-free by returning impl Iterator<Item = &GzHeader> with this implementation:

        self.0.headers.iter().chain(self.0.header())

let mut hdrs: Vec<&GzHeader> = self.0.headers.iter().collect();
if let Some(hdr) = &self.0.header() {
hdrs.push(hdr)
}
hdrs
}

/// Acquires a reference to the underlying reader.
Expand Down
6 changes: 3 additions & 3 deletions src/gz/read.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -237,9 +237,9 @@ impl<R: Read> MultiGzDecoder<R> {
}

impl<R> MultiGzDecoder<R> {
/// Returns the current header associated with this stream, if it's valid.
pub fn header(&self) -> Option<&GzHeader> {
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I think there is no need to make this a breaking change by removing the single-header access method. It can live side-by-side with the headers() method.

self.inner.header()
/// Returns the headers processed so far
pub fn headers(&self) -> Vec<&GzHeader> {
self.inner.headers()
}

/// Acquires a reference to the underlying reader.
Expand Down