Don't read forever on a file descriptor

Similarly to the recent commit to do this for networking, there's no reason that
a read on a file descriptor should continue reading until the entire buffer is
full. This makes sense when dealing with literal files, but when dealing with
things like stdin this doesn't make sense.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/libstd/io/pipe.rs b/src/libstd/io/pipe.rs
index 2349c64a84b..e3f2cc2384c 100644
--- a/src/libstd/io/pipe.rs
+++ b/src/libstd/io/pipe.rs
@@ -80,3 +80,25 @@ impl Writer for PipeStream {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    iotest!(fn partial_read() {
+        use os;
+        use io::pipe::PipeStream;
+
+        let os::Pipe { input, out } = os::pipe();
+        let out = PipeStream::open(out);
+        let mut input = PipeStream::open(input);
+        let (p, c) = Chan::new();
+        do spawn {
+            let mut out = out;
+            out.write([10]);
+            p.recv(); // don't close the pipe until the other read has finished
+        }
+
+        let mut buf = [0, ..10];
+        input.read(buf);
+        c.send(());
+    })
+}