feat: Make AsyncArrowWriter accepts AsyncFileWriter

Signed-off-by: Xuanwo <github@xuanwo.io>

parquet/src/arrow/async_writer/mod.rs

@@ -59,13 +59,59 @@ use crate::{
 };
 use arrow_array::RecordBatch;
 use arrow_schema::SchemaRef;
+use bytes::Bytes;
+use futures::future::BoxFuture;
+use futures::FutureExt;
 use tokio::io::{AsyncWrite, AsyncWriteExt};
 
-/// Encodes [`RecordBatch`] to parquet, outputting to an [`AsyncWrite`]
+/// The asynchronous interface used by [`AsyncArrowWriter`] to write parquet files
+pub trait AsyncFileWriter: Send {
+    /// Write the provided bytes to the underlying writer
+    ///
+    /// The underlying writer CAN decide to buffer the data or write it immediately.
+    /// This design allows the writer implementer to control the buffering and I/O scheduling.
+    fn write(&mut self, bs: Bytes) -> BoxFuture<'_, Result<()>>;
+
+    /// Flush any buffered data to the underlying writer and finish writing process.
+    ///
+    /// After `complete` returns `Ok(())`, caller SHOULD not call write again.
+    fn complete(&mut self) -> BoxFuture<'_, Result<()>>;
+}
+
+impl AsyncFileWriter for Box<dyn AsyncFileWriter> {
+    fn write(&mut self, bs: Bytes) -> BoxFuture<'_, Result<()>> {
+        self.as_mut().write(bs)
+    }
+
+    fn complete(&mut self) -> BoxFuture<'_, Result<()>> {
+        self.as_mut().complete()
+    }
+}
+
+impl<T: AsyncWrite + Unpin + Send> AsyncFileWriter for T {
+    fn write(&mut self, bs: Bytes) -> BoxFuture<'_, Result<()>> {
+        async move {
+            self.write_all(&bs).await?;
+            Ok(())
+        }
+        .boxed()
+    }
+
+    fn complete(&mut self) -> BoxFuture<'_, Result<()>> {
+        async move {
+            self.flush().await?;
+            self.shutdown().await?;
+            Ok(())
+        }
+        .boxed()
+    }
+}
+
+/// Encodes [`RecordBatch`] to parquet, outputting to an [`AsyncFileWriter`]
 ///
 /// ## Memory Usage
 ///
-/// This writer eagerly writes data as soon as possible to the underlying [`AsyncWrite`],
+/// This writer eagerly writes data as soon as possible to the underlying [`AsyncFileWriter`],
 /// permitting fine-grained control over buffering and I/O scheduling. However, the columnar
 /// nature of parquet forces data for an entire row group to be buffered in memory, before
 /// it can be flushed. Depending on the data and the configured row group size, this buffering
@@ -97,7 +143,7 @@ pub struct AsyncArrowWriter<W> {
     async_writer: W,
 }
 
-impl<W: AsyncWrite + Unpin + Send> AsyncArrowWriter<W> {
+impl<W: AsyncFileWriter> AsyncArrowWriter<W> {
     /// Try to create a new Async Arrow Writer
     pub fn try_new(
         writer: W,
@@ -178,7 +224,7 @@ impl<W: AsyncWrite + Unpin + Send> AsyncArrowWriter<W> {
 
         // Force to flush the remaining data.
         self.do_write().await?;
-        self.async_writer.shutdown().await?;
+        self.async_writer.complete().await?;
 
         Ok(metadata)
     }
@@ -188,12 +234,7 @@ impl<W: AsyncWrite + Unpin + Send> AsyncArrowWriter<W> {
         let buffer = self.sync_writer.inner_mut();
 
         self.async_writer
-            .write_all(buffer.as_slice())
-            .await
-            .map_err(|e| ParquetError::External(Box::new(e)))?;
-
-        self.async_writer
-            .flush()
+            .write(Bytes::copy_from_slice(buffer))
             .await
             .map_err(|e| ParquetError::External(Box::new(e)))?;