NixPath -> NixString and Error -> Errno

Author: arcnmx

src/errno.rs

@@ -1,6 +1,5 @@
 use libc::c_int;
 use std::{fmt, io, error, result};
-use Error;
 
 pub use self::consts::*;
 pub use self::consts::Errno::*;
@@ -74,7 +73,7 @@ impl Errno {
     /// should not be used when `-1` is not the errno sentinel value.
     pub fn result<S: ErrnoSentinel + PartialEq<S>>(value: S) -> Result<S> {
         if value == S::sentinel() {
-            Err(Error::Sys(Self::last()))
+            Err(Self::last())
         } else {
             Ok(value)
         }
@@ -117,7 +116,7 @@ impl From<Errno> for io::Error {
     }
 }
 
-pub type Result<T> = result::Result<T, Error>;
+pub type Result<T> = result::Result<T, Errno>;
 
 fn last() -> Errno {
     Errno::from_i32(errno())

src/fcntl.rs

@@ -1,4 +1,4 @@
-use NixPath;
+use NixString;
 use errno::{Errno, Result};
 use libc::{c_int, c_uint};
 use sys::stat::Mode;
@@ -97,10 +97,10 @@ mod ffi {
     }
 }
 
-pub fn open<P: ?Sized + NixPath>(path: &P, oflag: OFlag, mode: Mode) -> Result<RawFd> {
-    let fd = try!(path.with_nix_path(|cstr| {
-        unsafe { ffi::open(cstr.as_ptr(), oflag.bits(), mode.bits() as c_uint) }
-    }));
+pub fn open<P: NixString>(path: P, oflag: OFlag, mode: Mode) -> Result<RawFd> {
+    let fd = unsafe {
+        ffi::open(path.as_ref().as_ptr(), oflag.bits(), mode.bits() as c_uint)
+    };
 
     Errno::result(fd)
 }

src/lib.rs

@@ -21,6 +21,10 @@ extern crate nix_test as nixtest;
 // Re-exports
 pub use libc::{c_int, c_void};
 pub use errno::{Errno, Result};
+pub use nix_string::NixString;
+
+#[macro_use]
+mod nix_string;
 
 pub mod errno;
 pub mod features;
@@ -40,147 +44,3 @@ pub mod sched;
 
 pub mod sys;
 pub mod unistd;
-
-/*
- *
- * ===== Error =====
- *
- */
-
-use libc::c_char;
-use std::ptr;
-use std::ffi::CStr;
-use std::path::{Path, PathBuf};
-use std::os::unix::ffi::OsStrExt;
-use std::io;
-use std::fmt;
-use std::error;
-use libc::PATH_MAX;
-
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum Error {
-    Sys(errno::Errno),
-    InvalidPath,
-}
-
-impl Error {
-    pub fn from_errno(errno: errno::Errno) -> Error {
-        Error::Sys(errno)
-    }
-
-    pub fn last() -> Error {
-        Error::Sys(errno::Errno::last())
-    }
-
-    pub fn invalid_argument() -> Error {
-        Error::Sys(errno::EINVAL)
-    }
-
-    pub fn errno(&self) -> errno::Errno {
-        match *self {
-            Error::Sys(errno) => errno,
-            Error::InvalidPath => errno::Errno::EINVAL,
-        }
-    }
-}
-
-impl From<errno::Errno> for Error {
-    fn from(errno: errno::Errno) -> Error { Error::from_errno(errno) }
-}
-
-impl error::Error for Error {
-    fn description(&self) -> &str {
-        match self {
-            &Error::InvalidPath => "Invalid path",
-            &Error::Sys(ref errno) => errno.desc(),
-        }
-    }
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            &Error::InvalidPath => write!(f, "Invalid path"),
-            &Error::Sys(errno) => write!(f, "{:?}: {}", errno, errno.desc()),
-        }
-    }
-}
-
-impl From<Error> for io::Error {
-    fn from(err: Error) -> Self {
-        match err {
-            Error::InvalidPath => io::Error::new(io::ErrorKind::InvalidInput, err),
-            Error::Sys(errno) => io::Error::from_raw_os_error(errno as i32),
-        }
-    }
-}
-
-pub trait NixPath {
-    fn len(&self) -> usize;
-
-    fn with_nix_path<T, F>(&self, f: F) -> Result<T>
-        where F: FnOnce(&CStr) -> T;
-}
-
-impl NixPath for CStr {
-    fn len(&self) -> usize {
-        self.to_bytes().len()
-    }
-
-    fn with_nix_path<T, F>(&self, f: F) -> Result<T>
-            where F: FnOnce(&CStr) -> T {
-        // Equivalence with the [u8] impl.
-        if self.len() >= PATH_MAX as usize {
-            return Err(Error::InvalidPath);
-        }
-
-        Ok(f(self))
-    }
-}
-
-impl NixPath for [u8] {
-    fn len(&self) -> usize {
-        self.len()
-    }
-
-    fn with_nix_path<T, F>(&self, f: F) -> Result<T>
-            where F: FnOnce(&CStr) -> T {
-        let mut buf = [0u8; PATH_MAX as usize];
-
-        if self.len() >= PATH_MAX as usize {
-            return Err(Error::InvalidPath);
-        }
-
-        match self.iter().position(|b| *b == 0) {
-            Some(_) => Err(Error::InvalidPath),
-            None => {
-                unsafe {
-                    // TODO: Replace with bytes::copy_memory. rust-lang/rust#24028
-                    ptr::copy_nonoverlapping(self.as_ptr(), buf.as_mut_ptr(), self.len());
-                    Ok(f(CStr::from_ptr(buf.as_ptr() as *const c_char)))
-                }
-
-            }
-        }
-    }
-}
-
-impl NixPath for Path {
-    fn len(&self) -> usize {
-        self.as_os_str().as_bytes().len()
-    }
-
-    fn with_nix_path<T, F>(&self, f: F) -> Result<T> where F: FnOnce(&CStr) -> T {
-        self.as_os_str().as_bytes().with_nix_path(f)
-    }
-}
-
-impl NixPath for PathBuf {
-    fn len(&self) -> usize {
-        self.as_os_str().as_bytes().len()
-    }
-
-    fn with_nix_path<T, F>(&self, f: F) -> Result<T> where F: FnOnce(&CStr) -> T {
-        self.as_os_str().as_bytes().with_nix_path(f)
-    }
-}

src/mount.rs

@@ -1,5 +1,5 @@
 use libc::{c_ulong, c_int};
-use NixPath;
+use NixString;
 use errno::{Errno, Result};
 
 bitflags!(
@@ -50,18 +50,15 @@ bitflags!(
 );
 
 mod ffi {
-    use libc::{c_char, c_int};
+    use libc::{c_char, c_int, c_ulong, c_void};
 
     extern {
-        /*
-         * TODO: Bring back
         pub fn mount(
                 source: *const c_char,
                 target: *const c_char,
                 fstype: *const c_char,
                 flags: c_ulong,
                 data: *const c_void) -> c_int;
-                */
 
         pub fn umount(target: *const c_char) -> c_int;
 
@@ -72,47 +69,42 @@ mod ffi {
 /*
  * TODO: Bring this back with a test
  *
-pub fn mount<P1: ?Sized + NixPath, P2: ?Sized + NixPath, P3: ?Sized + NixPath, P4: ?Sized + NixPath>(
-        source: Option<&P1>,
+pub fn mount<P1: NixString, P2: NixString, P3: NixString, P4: NixString>(
+        source: Option<P1>,
         target: P2,
-        fstype: Option<&P3>,
+        fstype: Option<P3>,
         flags: MsFlags,
-        data: Option<&P4>) -> Result<()> {
+        data: Option<P4>) -> Result<()> {
+    use std::ffi::CStr;
+    use std::ptr;
     use libc;
 
-    let res = try!(try!(try!(try!(
-        source.with_nix_path(|source| {
-            target.with_nix_path(|target| {
-                fstype.with_nix_path(|fstype| {
-                    data.with_nix_path(|data| {
-                        unsafe {
-                            ffi::mount(source.as_ext_str(),
-                                       target.as_ext_str(),
-                                       fstype,
-                                       flags.bits,
-                                       data as *const libc::c_void)
-                        }
-                    })
-                })
-            })
-        })))));
+    let source = source.as_ref().map(NixString::as_ref);
+    let fstype = fstype.as_ref().map(NixString::as_ref);
+    let data = data.as_ref().map(NixString::as_ref);
+    let res = unsafe {
+        ffi::mount(source.map(CStr::as_ptr).unwrap_or(ptr::null()),
+            target.as_ref().as_ptr(),
+            fstype.map(CStr::as_ptr).unwrap_or(ptr::null()),
+            flags.bits,
+            data.map(CStr::as_ptr).unwrap_or(ptr::null()) as *const libc::c_void)
+    };
 
-    return from_ffi(res);
-}
-*/
+    Errno::result(res).map(drop)
+}*/
 
-pub fn umount<P: ?Sized + NixPath>(target: &P) -> Result<()> {
-    let res = try!(target.with_nix_path(|cstr| {
-        unsafe { ffi::umount(cstr.as_ptr()) }
-    }));
+pub fn umount<P: NixString>(target: P) -> Result<()> {
+    let res = unsafe {
+        ffi::umount(target.as_ref().as_ptr())
+    };
 
     Errno::result(res).map(drop)
 }
 
-pub fn umount2<P: ?Sized + NixPath>(target: &P, flags: MntFlags) -> Result<()> {
-    let res = try!(target.with_nix_path(|cstr| {
-        unsafe { ffi::umount2(cstr.as_ptr(), flags.bits) }
-    }));
+pub fn umount2<P: NixString>(target: P, flags: MntFlags) -> Result<()> {
+    let res = unsafe {
+        ffi::umount2(target.as_ref().as_ptr(), flags.bits)
+    };
 
     Errno::result(res).map(drop)
 }

src/nix_string.rs

@@ -0,0 +1,47 @@
+use std::ffi::{CStr, CString};
+use std::borrow::Cow;
+
+/// Represents a type that can be converted to a `&CStr` without fail.
+///
+/// Note: this trait exists in place of `AsRef<CStr>` because is not
+/// implemented until Rust 1.7.0
+pub trait NixString {
+    fn as_ref(&self) -> &CStr;
+}
+
+impl<'a> NixString for Cow<'a, CStr> {
+    fn as_ref(&self) -> &CStr {
+        self
+    }
+}
+
+impl NixString for CStr {
+    fn as_ref(&self) -> &CStr {
+        self
+    }
+}
+
+impl NixString for CString {
+    fn as_ref(&self) -> &CStr {
+        self
+    }
+}
+
+impl<'a, T: ?Sized + NixString> NixString for &'a T {
+    fn as_ref(&self) -> &CStr {
+        NixString::as_ref(*self)
+    }
+}
+
+impl<'a, T: ?Sized + NixString> NixString for &'a mut T {
+    fn as_ref(&self) -> &CStr {
+        NixString::as_ref(*self)
+    }
+}
+
+#[macro_export]
+macro_rules! cstr {
+    ($s:expr) => {
+        unsafe { ::std::ffi::CStr::from_ptr(concat!($s, "\0").as_ptr() as *const _) }
+    }
+}

src/sys/mman.rs

@@ -1,4 +1,4 @@
-use {NixPath, Error};
+use NixString;
 use errno::{Errno, Result};
 use fcntl::OFlag;
 use libc::{c_void, size_t, off_t, mode_t};
@@ -204,7 +204,7 @@ pub fn mmap(addr: *mut c_void, length: size_t, prot: MmapProt, flags: MmapFlag,
     let ret = unsafe { ffi::mmap(addr, length, prot, flags, fd, offset) };
 
     if ret as isize == MAP_FAILED  {
-        Err(Error::Sys(Errno::last()))
+        Err(Errno::last())
     } else {
         Ok(ret)
     }
@@ -222,20 +222,14 @@ pub fn msync(addr: *const c_void, length: size_t, flags: MmapSync) -> Result<()>
     Errno::result(unsafe { ffi::msync(addr, length, flags) }).map(drop)
 }
 
-pub fn shm_open<P: ?Sized + NixPath>(name: &P, flag: OFlag, mode: Mode) -> Result<RawFd> {
-    let ret = try!(name.with_nix_path(|cstr| {
-        unsafe {
-            ffi::shm_open(cstr.as_ptr(), flag.bits(), mode.bits() as mode_t)
-        }
-    }));
-
-    Errno::result(ret)
+pub fn shm_open<P: NixString>(name: P, flag: OFlag, mode: Mode) -> Result<RawFd> {
+    unsafe {
+        Errno::result(ffi::shm_open(name.as_ref().as_ptr(), flag.bits(), mode.bits() as mode_t))
+    }
 }
 
-pub fn shm_unlink<P: ?Sized + NixPath>(name: &P) -> Result<()> {
-    let ret = try!(name.with_nix_path(|cstr| {
-        unsafe { ffi::shm_unlink(cstr.as_ptr()) }
-    }));
-
-    Errno::result(ret).map(drop)
+pub fn shm_unlink<P: NixString>(name: P) -> Result<()> {
+    unsafe {
+        Errno::result(ffi::shm_unlink(name.as_ref().as_ptr())).map(drop)
+    }
 }