Implement ChunkReader for Bytes, deprecate SliceableCursor

parquet/src/arrow/arrow_reader.rs

@@ -248,6 +248,7 @@ impl ParquetRecordBatchReader {
 
 #[cfg(test)]
 mod tests {
+    use bytes::Bytes;
     use std::cmp::min;
     use std::convert::TryFrom;
     use std::fs::File;
@@ -285,7 +286,6 @@ mod tests {
     use crate::file::writer::SerializedFileWriter;
     use crate::schema::parser::parse_message_type;
     use crate::schema::types::{Type, TypePtr};
-    use crate::util::cursor::SliceableCursor;
     use crate::util::test_common::RandGen;
 
     #[test]
@@ -1162,7 +1162,7 @@ mod tests {
             114, 111, 119, 0, 130, 0, 0, 0, 80, 65, 82, 49,
         ];
 
-        let file = SliceableCursor::new(data);
+        let file = Bytes::from(data);
         let file_reader = SerializedFileReader::new(file).unwrap();
         let mut arrow_reader = ParquetFileArrowReader::new(Arc::new(file_reader));
 

parquet/src/arrow/arrow_writer.rs

@@ -689,6 +689,7 @@ fn get_fsb_array_slice(
 mod tests {
     use super::*;
 
+    use bytes::Bytes;
     use std::fs::File;
     use std::sync::Arc;
 
@@ -750,7 +751,7 @@ mod tests {
             writer.close().unwrap();
         }
 
-        let cursor = crate::file::serialized_reader::SliceableCursor::new(buffer);
+        let cursor = Bytes::from(buffer);
         let reader = SerializedFileReader::new(cursor).unwrap();
         let mut arrow_reader = ParquetFileArrowReader::new(Arc::new(reader));
         let mut record_batch_reader = arrow_reader.get_record_reader(1024).unwrap();

parquet/src/file/footer.rs

@@ -160,11 +160,11 @@ fn parse_column_orders(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use bytes::Bytes;
 
     use crate::basic::SortOrder;
     use crate::basic::Type;
     use crate::schema::types::Type as SchemaType;
-    use crate::util::cursor::SliceableCursor;
     use parquet_format::TypeDefinedOrder;
 
     #[test]
@@ -180,7 +180,7 @@ mod tests {
 
     #[test]
     fn test_parse_metadata_corrupt_footer() {
-        let data = SliceableCursor::new(Arc::new(vec![1, 2, 3, 4, 5, 6, 7, 8]));
+        let data = Bytes::from(vec![1, 2, 3, 4, 5, 6, 7, 8]);
         let reader_result = parse_metadata(&data);
         assert!(reader_result.is_err());
         assert_eq!(
@@ -191,8 +191,7 @@ mod tests {
 
     #[test]
     fn test_parse_metadata_invalid_length() {
-        let test_file =
-            SliceableCursor::new(Arc::new(vec![0, 0, 0, 255, b'P', b'A', b'R', b'1']));
+        let test_file = Bytes::from(vec![0, 0, 0, 255, b'P', b'A', b'R', b'1']);
         let reader_result = parse_metadata(&test_file);
         assert!(reader_result.is_err());
         assert_eq!(
@@ -205,8 +204,7 @@ mod tests {
 
     #[test]
     fn test_parse_metadata_invalid_start() {
-        let test_file =
-            SliceableCursor::new(Arc::new(vec![255, 0, 0, 0, b'P', b'A', b'R', b'1']));
+        let test_file = Bytes::from(vec![255, 0, 0, 0, b'P', b'A', b'R', b'1']);
         let reader_result = parse_metadata(&test_file);
         assert!(reader_result.is_err());
         assert_eq!(

parquet/src/file/serialized_reader.rs

@@ -18,6 +18,7 @@
 //! Contains implementations of the reader traits FileReader, RowGroupReader and PageReader
 //! Also contains implementations of the ChunkReader for files (with buffering) and byte arrays (RAM)
 
+use bytes::{Buf, Bytes};
 use std::{convert::TryFrom, fs::File, io::Read, path::Path, sync::Arc};
 
 use parquet_format::{PageHeader, PageType};
@@ -36,6 +37,7 @@ use crate::util::{io::TryClone, memory::ByteBufferPtr};
 
 // export `SliceableCursor` and `FileSource` publically so clients can
 // re-use the logic in their own ParquetFileWriter wrappers
+#[allow(deprecated)]
 pub use crate::util::{cursor::SliceableCursor, io::FileSource};
 
 // ----------------------------------------------------------------------
@@ -61,12 +63,35 @@ impl ChunkReader for File {
     }
 }
 
+impl Length for Bytes {
+    fn len(&self) -> u64 {
+        self.len() as u64
+    }
+}
+
+impl TryClone for Bytes {
+    fn try_clone(&self) -> std::io::Result<Self> {
+        Ok(self.clone())
+    }
+}
+
+impl ChunkReader for Bytes {
+    type T = bytes::buf::Reader<Bytes>;
+
+    fn get_read(&self, start: u64, length: usize) -> Result<Self::T> {
+        let start = start as usize;
+        Ok(self.slice(start..start + length).reader())
+    }
+}
+
+#[allow(deprecated)]
 impl Length for SliceableCursor {
     fn len(&self) -> u64 {
         SliceableCursor::len(self)
     }
 }
 
+#[allow(deprecated)]
 impl ChunkReader for SliceableCursor {
     type T = SliceableCursor;
 
@@ -521,7 +546,7 @@ mod tests {
         get_test_file("alltypes_plain.parquet")
             .read_to_end(&mut buf)
             .unwrap();
-        let cursor = SliceableCursor::new(buf);
+        let cursor = Bytes::from(buf);
         let read_from_cursor = SerializedFileReader::new(cursor).unwrap();
 
         let test_file = get_test_file("alltypes_plain.parquet");

parquet/src/file/writer.rs

@@ -541,6 +541,7 @@ impl<'a, W: Write> PageWriter for SerializedPageWriter<'a, W> {
 mod tests {
     use super::*;
 
+    use bytes::Bytes;
     use std::{fs::File, io::Cursor};
 
     use crate::basic::{Compression, Encoding, LogicalType, Repetition, Type};
@@ -1054,7 +1055,7 @@ mod tests {
     }
 
     fn test_bytes_roundtrip(data: Vec<Vec<i32>>) {
-        let mut cursor = Cursor::new(vec![]);
+        let mut buffer = vec![];
 
         let schema = Arc::new(
             types::Type::group_type_builder("schema")
@@ -1072,7 +1073,7 @@ mod tests {
         {
             let props = Arc::new(WriterProperties::builder().build());
             let mut writer =
-                SerializedFileWriter::new(&mut cursor, schema, props).unwrap();
+                SerializedFileWriter::new(&mut buffer, schema, props).unwrap();
 
             for subset in &data {
                 let mut row_group_writer = writer.next_row_group().unwrap();
@@ -1089,9 +1090,7 @@ mod tests {
             writer.close().unwrap();
         }
 
-        let buffer = cursor.into_inner();
-
-        let reading_cursor = crate::file::serialized_reader::SliceableCursor::new(buffer);
+        let reading_cursor = Bytes::from(buffer);
         let reader = SerializedFileReader::new(reading_cursor).unwrap();
 
         assert_eq!(reader.num_row_groups(), data.len());

parquet/src/util/cursor.rs

@@ -26,13 +26,15 @@ use std::{cmp, fmt};
 /// because the lack of Generic Associated Type implies that you would require complex lifetime propagation when
 /// returning such a cursor.
 #[allow(clippy::rc_buffer)]
+#[deprecated = "use bytes::Bytes instead"]
 pub struct SliceableCursor {
     inner: Arc<Vec<u8>>,
     start: u64,
     length: usize,
     pos: u64,
 }
 
+#[allow(deprecated)]
 impl fmt::Debug for SliceableCursor {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("SliceableCursor")
@@ -44,6 +46,7 @@ impl fmt::Debug for SliceableCursor {
     }
 }
 
+#[allow(deprecated)]
 impl SliceableCursor {
     pub fn new(content: impl Into<Arc<Vec<u8>>>) -> Self {
         let inner = content.into();
@@ -90,6 +93,7 @@ impl SliceableCursor {
 }
 
 /// Implementation inspired by std::io::Cursor
+#[allow(deprecated)]
 impl Read for SliceableCursor {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         let n = Read::read(&mut self.remaining_slice(), buf)?;
@@ -98,6 +102,7 @@ impl Read for SliceableCursor {
     }
 }
 
+#[allow(deprecated)]
 impl Seek for SliceableCursor {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         let new_pos = match pos {
@@ -204,12 +209,14 @@ mod tests {
     use super::*;
 
     /// Create a SliceableCursor of all u8 values in ascending order
+    #[allow(deprecated)]
     fn get_u8_range() -> SliceableCursor {
         let data: Vec<u8> = (0u8..=255).collect();
         SliceableCursor::new(data)
     }
 
     /// Reads all the bytes in the slice and checks that it matches the u8 range from start to end_included
+    #[allow(deprecated)]
     fn check_read_all(mut cursor: SliceableCursor, start: u8, end_included: u8) {
         let mut target = vec![];
         let cursor_res = cursor.read_to_end(&mut target);