auto merge of #13897 : aturon/rust/issue-6085, r=bjz

The `std::bitflags::bitflags!` macro did not provide support for
adding attributes to the generates structure, due to limitations in
the parser for macros. This patch works around the parser limitations
by requiring a `flags` keyword in the `bitflags!` invocations:

    bitflags!(
        #[deriving(Hash)]
        #[doc="Three flags"]
        flags Flags: u32 {
            FlagA       = 0x00000001,
            FlagB       = 0x00000010,
            FlagC       = 0x00000100
        }
    )

The intent of `std::bitflags` is to allow building type-safe wrappers
around C-style flags APIs. But in addition to construction these flags
from the Rust side, we need a way to convert them from the C
side. This patch adds a `from_bits` function, which is unsafe since
the bits in question may not represent a valid combination of flags.

Finally, this patch changes `std::io::FilePermissions` from an exposed
`u32` representation to a typesafe representation (that only allows valid
flag combinations) using the `std::bitflags`.

Closes #6085.

2 files changed, 9 insertions, 5 deletions

diff --git a/src/libnative/io/file_unix.rs b/src/libnative/io/file_unix.rs
index 7c19eb54326..94ca6027841 100644
--- a/src/libnative/io/file_unix.rs
+++ b/src/libnative/io/file_unix.rs
@@ -335,7 +335,7 @@ pub fn open(path: &CString, fm: io::FileMode, fa: io::FileAccess)
 
 pub fn mkdir(p: &CString, mode: io::FilePermission) -> IoResult<()> {
     super::mkerr_libc(retry(|| unsafe {
-        libc::mkdir(p.with_ref(|p| p), mode as libc::mode_t)
+        libc::mkdir(p.with_ref(|p| p), mode.bits() as libc::mode_t)
     }))
 }
 
@@ -392,7 +392,7 @@ pub fn rename(old: &CString, new: &CString) -> IoResult<()> {
 
 pub fn chmod(p: &CString, mode: io::FilePermission) -> IoResult<()> {
     super::mkerr_libc(retry(|| unsafe {
-        libc::chmod(p.with_ref(|p| p), mode as libc::mode_t)
+        libc::chmod(p.with_ref(|p| p), mode.bits() as libc::mode_t)
     }))
 }
 
@@ -470,7 +470,9 @@ fn mkstat(stat: &libc::stat, path: &CString) -> io::FileStat {
         path: Path::new(path),
         size: stat.st_size as u64,
         kind: kind,
-        perm: (stat.st_mode) as io::FilePermission & io::AllPermissions,
+        perm: unsafe {
+            io::FilePermission::from_bits(stat.st_mode as u32) & io::AllPermissions
+        },
         created: mktime(stat.st_ctime as u64, stat.st_ctime_nsec as u64),
         modified: mktime(stat.st_mtime as u64, stat.st_mtime_nsec as u64),
         accessed: mktime(stat.st_atime as u64, stat.st_atime_nsec as u64),
diff --git a/src/libnative/io/file_win32.rs b/src/libnative/io/file_win32.rs
index aae15a86614..54bb2201314 100644
--- a/src/libnative/io/file_win32.rs
+++ b/src/libnative/io/file_win32.rs
@@ -392,7 +392,7 @@ pub fn rename(old: &CString, new: &CString) -> IoResult<()> {
 
 pub fn chmod(p: &CString, mode: io::FilePermission) -> IoResult<()> {
     super::mkerr_libc(as_utf16_p(p.as_str().unwrap(), |p| unsafe {
-        libc::wchmod(p, mode as libc::c_int)
+        libc::wchmod(p, mode.bits() as libc::c_int)
     }))
 }
 
@@ -471,7 +471,9 @@ fn mkstat(stat: &libc::stat, path: &CString) -> io::FileStat {
         path: Path::new(path),
         size: stat.st_size as u64,
         kind: kind,
-        perm: (stat.st_mode) as io::FilePermission & io::AllPermissions,
+        perm: unsafe {
+          io::FilePermission::from_bits(stat.st_mode as u32)  & io::AllPermissions
+        },
         created: stat.st_ctime as u64,
         modified: stat.st_mtime as u64,
         accessed: stat.st_atime as u64,