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https://issues.apache.org/jira/browse/ARROW-7768?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wes McKinney updated ARROW-7768:
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Summary: [Rust] Implement Length and TryClone traits for Cursor<Vec<u8>> in
reader.rs (was: Implement Length and TryClone traits for Cursor<Vec<u8>> in
reader.rs)
> [Rust] Implement Length and TryClone traits for Cursor<Vec<u8>> in reader.rs
> ----------------------------------------------------------------------------
>
> Key: ARROW-7768
> URL: https://issues.apache.org/jira/browse/ARROW-7768
> Project: Apache Arrow
> Issue Type: Improvement
> Components: Rust
> Reporter: David Kegley
> Priority: Minor
>
> Currently Length and TryClone are implemented for Cursor<&'a [u8]> in
> src/file/reader.rs
> Attempting to create a cursor from a Vec<u8>...
> {code:java}
> fn test_cursor_and_file_has_the_same_behaviour() {
> let mut buf: Vec<u8> = Vec::new();
> get_test_file("alltypes_plain.parquet")
> .read_to_end(&mut buf)
> .unwrap();
> let cursor = Cursor::new(buf.as_slice());
> ...
> {code}
>
> results in:
> {code:java}
> `buf` does not live long enough
> borrowed value does not live long enough
> rustc(E0597)
> reader.rs(681, 34): borrowed value does not live long enough
> reader.rs(681, 34): argument requires that `buf` is borrowed for `'static`
> reader.rs(691, 5): `buf` dropped here while still borrowed
> {code}
>
> Implementing Length and TryClone for Cursor<Vec<u8>> would allow for:
> {code:java}
> fn test_cursor_and_file_has_the_same_behaviour() {
> let mut buf: Vec<u8> = Vec::new();
> get_test_file("alltypes_plain.parquet")
> .read_to_end(&mut buf)
> .unwrap();
> let cursor = Cursor::new(buf);
> let read_from_cursor = SerializedFileReader::new(cursor).unwrap();
> ...
> {code}
> Otherwise, buf: Vec<u8> must be declared static in order to initialize a
> SerializedFileReader from a Cursor.
> I'm new to rust so perhaps this is the intended behavior, but if not I'm
> happy to submit a PR for this
>
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