exa/src/feature/xattr_linux.rs

122 lines
3.9 KiB
Rust

//! Extended attribute support for darwin
extern crate libc;
use std::ffi::CString;
use std::ptr;
use std::old_io as io;
use std::old_path::GenericPath;
use std::old_path::posix::Path;
use self::libc::{size_t, ssize_t, c_char, c_void};
extern "C" {
fn listxattr(path: *const c_char, list: *mut c_char, size: size_t) -> ssize_t;
fn llistxattr(path: *const c_char, list: *mut c_char, size: size_t) -> ssize_t;
fn getxattr(path: *const c_char, name: *const c_char,
value: *mut c_void, size: size_t
) -> ssize_t;
fn lgetxattr(path: *const c_char, name: *const c_char,
value: *mut c_void, size: size_t
) -> ssize_t;
}
/// Attributes which can be passed to `Attribute::list_with_flags`
#[derive(Copy, Clone)]
pub enum FollowSymlinks {
Yes,
No
}
/// Extended attribute
#[derive(Debug, Clone)]
pub struct Attribute {
name: String,
size: usize,
}
impl Attribute {
/// Lists the extended attribute of `path`.
/// Does follow symlinks by default.
pub fn list_attrs(path: &Path, do_follow: FollowSymlinks) -> io::IoResult<Vec<Attribute>> {
let (listxattr, getxattr) = match do_follow {
FollowSymlinks::Yes => (listxattr, getxattr),
FollowSymlinks::No => (llistxattr, lgetxattr),
};
let c_path = try!(CString::new(path.as_vec()));
let bufsize = unsafe {
listxattr(c_path.as_ptr(), ptr::null_mut(), 0)
};
if bufsize > 0 {
let mut buf = vec![0u8; bufsize as usize];
let err = unsafe { listxattr(
c_path.as_ptr(),
buf.as_mut_ptr() as *mut c_char,
bufsize as size_t
)};
if err > 0 {
// End indicies of the attribute names
// the buffer contains 0-terminates c-strings
let idx = buf.iter().enumerate().filter_map(|(i, v)|
if *v == 0 { Some(i) } else { None }
);
let mut names = Vec::new();
let mut start = 0;
for end in idx {
let c_end = end + 1; // end of the c-string (including 0)
let size = unsafe {
getxattr(
c_path.as_ptr(),
buf[start..c_end].as_ptr() as *const c_char,
ptr::null_mut(), 0
)
};
if size > 0 {
names.push(Attribute {
name: String::from_utf8_lossy(&buf[start..end]).into_owned(),
size: size as usize
});
}
start = c_end;
}
Ok(names)
} else {
Err(io::IoError {
kind: io::OtherIoError,
desc: "could not read extended attributes",
detail: None
})
}
} else {
Err(io::IoError {
kind: io::OtherIoError,
desc: "could not read extended attributes",
detail: None
})
}
}
/// Getter for name
pub fn name(&self) -> &str {
&self.name
}
/// Getter for size
pub fn size(&self) -> usize {
self.size
}
/// Lists the extended attributes.
/// Follows symlinks like `stat`
pub fn list(path: &Path) -> io::IoResult<Vec<Attribute>> {
Attribute::list_attrs(path, FollowSymlinks::Yes)
}
/// Lists the extended attributes.
/// Does not follow symlinks like `lstat`
pub fn llist(path: &Path) -> io::IoResult<Vec<Attribute>> {
Attribute::list_attrs(path, FollowSymlinks::No)
}
/// Returns true if the extended attribute feature is implemented on this platform.
#[inline(always)]
pub fn feature_implemented() -> bool { true }
}