native: Recognize EISDIR

This recognizes the EISDIR error code on both windows and unix platforms to
provide a more descriptive error condition.

Author: alexcrichton

src/libnative/io/mod.rs

@@ -105,6 +105,13 @@ fn translate_error(errno: i32, detail: bool) -> IoError {
             libc::WSAEADDRINUSE => (io::ConnectionRefused, "address in use"),
             libc::ERROR_BROKEN_PIPE => (io::EndOfFile, "the pipe has ended"),
 
+            // libuv maps this error code to EISDIR. we do too. if it is found
+            // to be incorrect, we can add in some more machinery to only
+            // return this message when ERROR_INVALID_FUNCTION after certain
+            // win32 calls.
+            libc::ERROR_INVALID_FUNCTION => (io::InvalidInput,
+                                             "illegal operation on a directory"),
+
             x => {
                 debug!("ignoring {}: {}", x, os::last_os_error());
                 (io::OtherIoError, "unknown error")
@@ -127,6 +134,7 @@ fn translate_error(errno: i32, detail: bool) -> IoError {
             libc::EADDRNOTAVAIL => (io::ConnectionRefused, "address not available"),
             libc::EADDRINUSE => (io::ConnectionRefused, "address in use"),
             libc::ENOENT => (io::FileNotFound, "no such file or directory"),
+            libc::EISDIR => (io::InvalidInput, "illegal operation on a directory"),
 
             // These two constants can have the same value on some systems, but
             // different values on others, so we can't use a match clause

src/libstd/libc.rs

@@ -1623,6 +1623,7 @@ pub mod consts {
             pub static O_NOINHERIT: c_int = 128;
 
             pub static ERROR_SUCCESS : c_int = 0;
+            pub static ERROR_INVALID_FUNCTION: c_int = 1;
             pub static ERROR_FILE_NOT_FOUND: c_int = 2;
             pub static ERROR_ACCESS_DENIED: c_int = 5;
             pub static ERROR_INVALID_HANDLE : c_int = 6;