wincolor: Re-fetch the console on all calls

The primary motivation for this commit was rust-lang/cargo#4189 where dropping a
`wincolor::Console` would call `CloseHandle` to close the console handle. Cargo
creates a few `Console` instances so it ended up closing stdout a little
earlier as intended!

The `GetStdHandle` function returns handles I believe aren't intended to be
closed (as there's no refcounting). I believe libstd doesn't close these
handles.

This commit also moves to calling `GetStdHandle` on demand which libstd changed
to doing so recently as well, preventing caching of stale handles that change
over time with calls to `SetStdHandle`.

1 files changed, 7 insertions, 14 deletions

diff --git a/wincolor/src/win.rs b/wincolor/src/win.rs
index e61240b7..c0ad8359 100644
--- a/wincolor/src/win.rs
+++ b/wincolor/src/win.rs
@@ -2,7 +2,7 @@ use std::io;
 use std::mem;
 
 use kernel32;
-use winapi::{DWORD, HANDLE, WORD};
+use winapi::{DWORD, WORD};
 use winapi::winbase::{STD_ERROR_HANDLE, STD_OUTPUT_HANDLE};
 use winapi::wincon::{
     FOREGROUND_BLUE as FG_BLUE,
@@ -30,33 +30,25 @@ const FG_WHITE: DWORD = FG_BLUE | FG_GREEN | FG_RED;
 /// stdout before setting new text attributes.
 #[derive(Debug)]
 pub struct Console {
-    handle: HANDLE,
+    handle_id: DWORD,
     start_attr: TextAttributes,
     cur_attr: TextAttributes,
 }
 
-unsafe impl Send for Console {}
-
-impl Drop for Console {
-    fn drop(&mut self) {
-        unsafe { kernel32::CloseHandle(self.handle); }
-    }
-}
-
 impl Console {
     /// Get a console for a standard I/O stream.
     fn create_for_stream(handle_id: DWORD) -> io::Result<Console> {
         let mut info = unsafe { mem::zeroed() };
-        let (handle, res) = unsafe {
+        let res = unsafe {
             let handle = kernel32::GetStdHandle(handle_id);
-            (handle, kernel32::GetConsoleScreenBufferInfo(handle, &mut info))
+            kernel32::GetConsoleScreenBufferInfo(handle, &mut info)
         };
         if res == 0 {
             return Err(io::Error::last_os_error());
         }
         let attr = TextAttributes::from_word(info.wAttributes);
         Ok(Console {
-            handle: handle,
+            handle_id: handle_id,
             start_attr: attr,
             cur_attr: attr,
         })
@@ -80,7 +72,8 @@ impl Console {
     fn set(&mut self) -> io::Result<()> {
         let attr = self.cur_attr.to_word();
         let res = unsafe {
-            kernel32::SetConsoleTextAttribute(self.handle, attr)
+            let handle = kernel32::GetStdHandle(self.handle_id);
+            kernel32::SetConsoleTextAttribute(handle, attr)
         };
         if res == 0 {
             return Err(io::Error::last_os_error());