Add function for finding what a InputStream or OutputStream is attached to

runtime/bin/socket_linux.cc

Index: runtime/bin/socket_linux.cc
diff --git a/runtime/bin/socket_linux.cc b/runtime/bin/socket_linux.cc
index d8be1dc59490a7a50778ca11fc777b770c8ecc63..4740771dca6d1cc8ef47715156089f61df6e45f2 100644
--- a/runtime/bin/socket_linux.cc
+++ b/runtime/bin/socket_linux.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -6,9 +6,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #include "bin/fdutils.h"
+#include "bin/file.h"
 #include "bin/log.h"
 #include "bin/socket.h"
 
@@ -139,6 +141,17 @@ void Socket::GetError(intptr_t fd, OSError* os_error) {
 }
 
 
+int Socket::GetType(intptr_t fd) {
+  struct stat buf;
+  if (isatty(fd)) return File::kTerminal;
+  int result = fstat(fd, &buf);
+  if (result == -1) return -1;
+  if (S_ISFIFO(buf.st_mode)) return File::kPipe;
+  if (S_ISREG(buf.st_mode)) return File::kFile;
+  return File::kOther;
+}
+
+
 intptr_t Socket::GetStdioHandle(int num) {
   return static_cast<intptr_t>(num);
 }