Move as much I/O as possible off of native::io

When uv's TTY I/O is used for the stdio streams, the file descriptors are put
into a non-blocking mode. This means that other concurrent writes to the same
stream can fail with EAGAIN or EWOULDBLOCK. By all I/O to event-loop I/O, we
avoid this error.

There is one location which cannot move, which is the runtime's dumb_println
function. This was implemented to handle the EAGAIN and EWOULDBLOCK errors and
simply retry again and again.

1 files changed, 11 insertions, 2 deletions

diff --git a/src/libstd/rt/util.rs b/src/libstd/rt/util.rs
index 647d88c26f2..f15aa01db95 100644
--- a/src/libstd/rt/util.rs
+++ b/src/libstd/rt/util.rs
@@ -71,9 +71,18 @@ pub fn default_sched_threads() -> uint {
 
 pub fn dumb_println(args: &fmt::Arguments) {
     use rt::io::native::stdio::stderr;
-    use rt::io::Writer;
+    use rt::io::{Writer, io_error, ResourceUnavailable};
     let mut out = stderr();
-    fmt::writeln(&mut out as &mut Writer, args);
+
+    let mut again = true;
+    do io_error::cond.trap(|e| {
+        again = e.kind == ResourceUnavailable;
+    }).inside {
+        while again {
+            again = false;
+            fmt::writeln(&mut out as &mut Writer, args);
+        }
+    }
 }
 
 pub fn abort(msg: &str) -> ! {