move cli to top level

cli/src/util/io.rs

@@ -0,0 +1,59 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+use std::io;
+
+use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
+
+pub trait ReportCopyProgress {
+    fn report_progress(&mut self, bytes_so_far: u64, total_bytes: u64);
+}
+
+/// Type that doesn't emit anything for download progress.
+pub struct SilentCopyProgress();
+
+impl ReportCopyProgress for SilentCopyProgress {
+    fn report_progress(&mut self, _bytes_so_far: u64, _total_bytes: u64) {}
+}
+
+/// Copies from the reader to the writer, reporting progress to the provided
+/// reporter every so often.
+pub async fn copy_async_progress<T, R, W>(
+    mut reporter: T,
+    reader: &mut R,
+    writer: &mut W,
+    total_bytes: u64,
+) -> io::Result<u64>
+where
+    R: AsyncRead + Unpin,
+    W: AsyncWrite + Unpin,
+    T: ReportCopyProgress,
+{
+    let mut buf = vec![0; 8 * 1024];
+    let mut bytes_so_far = 0;
+    let mut bytes_last_reported = 0;
+    let report_granularity = std::cmp::min(total_bytes / 10, 2 * 1024 * 1024);
+
+    reporter.report_progress(0, total_bytes);
+
+    loop {
+        let read_buf = match reader.read(&mut buf).await {
+            Ok(0) => break,
+            Ok(n) => &buf[..n],
+            Err(e) => return Err(e),
+        };
+
+        writer.write_all(read_buf).await?;
+
+        bytes_so_far += read_buf.len() as u64;
+        if bytes_so_far - bytes_last_reported > report_granularity {
+            bytes_last_reported = bytes_so_far;
+            reporter.report_progress(bytes_so_far, total_bytes);
+        }
+    }
+
+    reporter.report_progress(bytes_so_far, total_bytes);
+
+    Ok(bytes_so_far)
+}