Implement --close

This option causes the sending side to not send any data and instead
immeditally send an EOF.  This can be useful when you are only
interested in sending data in one direction.

Closes #10

Author: eminence

src/main.rs

@@ -99,6 +99,10 @@ pub struct CommonArgs {
     /// The verbosity level. Repeat to increase verbosity.
     #[clap(short = 'v', long, action = clap::ArgAction::Count)]
     pub verbose: u8,
+
+    /// Immediately close our sending side, indicating that we will not transmit any data
+    #[clap(long)]
+    pub close: bool,
 }
 
 impl CommonArgs {
@@ -323,7 +327,11 @@ async fn listen_stdio(args: ListenArgs) -> Result<()> {
             snafu::ensure_whatever!(buf == dumbpipe::HANDSHAKE, "invalid handshake");
         }
         tracing::info!("forwarding stdin/stdout to {}", remote_node_id);
-        forward_bidi(tokio::io::stdin(), tokio::io::stdout(), r, s).await?;
+        if args.common.close {
+            forward_bidi(tokio::io::empty(), tokio::io::stdout(), r, s).await?;
+        } else {
+            forward_bidi(tokio::io::stdin(), tokio::io::stdout(), r, s).await?;
+        }
         // stop accepting connections after the first successful one
         break;
     }
@@ -357,7 +365,11 @@ async fn connect_stdio(args: ConnectArgs) -> Result<()> {
         s.write_all(&dumbpipe::HANDSHAKE).await.e()?;
     }
     tracing::info!("forwarding stdin/stdout to {}", remote_node_id);
-    forward_bidi(tokio::io::stdin(), tokio::io::stdout(), r, s).await?;
+    if args.common.close {
+        forward_bidi(tokio::io::empty(), tokio::io::stdout(), r, s).await?;
+    } else {
+        forward_bidi(tokio::io::stdin(), tokio::io::stdout(), r, s).await?;
+    }
     tokio::io::stdout().flush().await.e()?;
     Ok(())
 }