alamb commented on a change in pull request #8726:
URL: https://github.com/apache/arrow/pull/8726#discussion_r527978914
##########
File path: rust/parquet/src/util/cursor.rs
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@@ -129,6 +132,56 @@ impl Seek for SliceableCursor {
}
}
+/// Use this type to write Parquet to memory rather than a file.
+#[derive(Debug, Default, Clone)]
+pub struct WriteableCursor {
+ buffer: Arc<Mutex<Cursor<Vec<u8>>>>,
+}
+
+impl WriteableCursor {
+ /// Consume this instance and return the underlying buffer as long as
there are no other
+ /// references to this instance.
+ pub fn into_inner(self) -> Option<Vec<u8>> {
+ Arc::try_unwrap(self.buffer)
+ .ok()
+ .and_then(|mutex| mutex.into_inner().ok())
+ .map(|cursor| cursor.into_inner())
+ }
+
+ /// Returns a clone of the underlying buffer
+ pub fn data(&self) -> Vec<u8> {
+ let inner = self.buffer.lock().unwrap();
+ inner.get_ref().to_vec()
+ }
+}
+
+impl TryClone for WriteableCursor {
+ fn try_clone(&self) -> std::io::Result<Self> {
+ Ok(Self {
+ buffer: self.buffer.clone(),
Review comment:
THis is clever. 👍
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