pub const MAIN_SEP_STR: &str = "\\";
pub const MAIN_SEP: char = '\\';
+// The unsafety here stems from converting between `&OsStr` and `&[u8]`
+// and back. This is safe to do because (1) we only look at ASCII
+// contents of the encoding and (2) new &OsStr values are produced
+// only from ASCII-bounded slices of existing &OsStr values.
fn os_str_as_u8_slice(s: &OsStr) -> &[u8] {
unsafe { mem::transmute(s) }
}
pub fn parse_prefix(path: &OsStr) -> Option<Prefix<'_>> {
use Prefix::{DeviceNS, Disk, Verbatim, VerbatimDisk, VerbatimUNC, UNC};
- unsafe {
- // The unsafety here stems from converting between &OsStr and &[u8]
- // and back. This is safe to do because (1) we only look at ASCII
- // contents of the encoding and (2) new &OsStr values are produced
- // only from ASCII-bounded slices of existing &OsStr values.
- let path = os_str_as_u8_slice(path);
- // \\
- if let Some(path) = path.strip_prefix(br"\\") {
- // \\?\
- if let Some(path) = path.strip_prefix(br"?\") {
- // \\?\UNC\server\share
- if let Some(path) = path.strip_prefix(br"UNC\") {
- let (server, share) = match get_first_two_components(path, is_verbatim_sep) {
- Some((server, share)) => {
- (u8_slice_as_os_str(server), u8_slice_as_os_str(share))
- }
- None => (u8_slice_as_os_str(path), OsStr::new("")),
- };
- return Some(VerbatimUNC(server, share));
- } else {
- // \\?\path
- match path {
- // \\?\C:\path
- [c, b':', b'\\', ..] if is_valid_drive_letter(*c) => {
- return Some(VerbatimDisk(c.to_ascii_uppercase()));
- }
- // \\?\cat_pics
- _ => {
- let idx = path.iter().position(|&b| b == b'\\').unwrap_or(path.len());
- let slice = &path[..idx];
- return Some(Verbatim(u8_slice_as_os_str(slice)));
- }
+ let path = os_str_as_u8_slice(path);
+
+ // \\
+ if let Some(path) = path.strip_prefix(br"\\") {
+ // \\?\
+ if let Some(path) = path.strip_prefix(br"?\") {
+ // \\?\UNC\server\share
+ if let Some(path) = path.strip_prefix(br"UNC\") {
+ let (server, share) = match get_first_two_components(path, is_verbatim_sep) {
+ Some((server, share)) => unsafe {
+ (u8_slice_as_os_str(server), u8_slice_as_os_str(share))
+ },
+ None => (unsafe { u8_slice_as_os_str(path) }, OsStr::new("")),
+ };
+ return Some(VerbatimUNC(server, share));
+ } else {
+ // \\?\path
+ match path {
+ // \\?\C:\path
+ [c, b':', b'\\', ..] if is_valid_drive_letter(*c) => {
+ return Some(VerbatimDisk(c.to_ascii_uppercase()));
+ }
+ // \\?\cat_pics
+ _ => {
+ let idx = path.iter().position(|&b| b == b'\\').unwrap_or(path.len());
+ let slice = &path[..idx];
+ return Some(Verbatim(unsafe { u8_slice_as_os_str(slice) }));
}
}
- } else if let Some(path) = path.strip_prefix(b".\\") {
- // \\.\COM42
- let idx = path.iter().position(|&b| b == b'\\').unwrap_or(path.len());
- let slice = &path[..idx];
- return Some(DeviceNS(u8_slice_as_os_str(slice)));
- }
- match get_first_two_components(path, is_sep_byte) {
- Some((server, share)) if !server.is_empty() && !share.is_empty() => {
- // \\server\share
- return Some(UNC(u8_slice_as_os_str(server), u8_slice_as_os_str(share)));
- }
- _ => {}
}
- } else if let [c, b':', ..] = path {
- // C:
- if is_valid_drive_letter(*c) {
- return Some(Disk(c.to_ascii_uppercase()));
+ } else if let Some(path) = path.strip_prefix(b".\\") {
+ // \\.\COM42
+ let idx = path.iter().position(|&b| b == b'\\').unwrap_or(path.len());
+ let slice = &path[..idx];
+ return Some(DeviceNS(unsafe { u8_slice_as_os_str(slice) }));
+ }
+ match get_first_two_components(path, is_sep_byte) {
+ Some((server, share)) if !server.is_empty() && !share.is_empty() => {
+ // \\server\share
+ return Some(unsafe { UNC(u8_slice_as_os_str(server), u8_slice_as_os_str(share)) });
}
+ _ => {}
+ }
+ } else if let [c, b':', ..] = path {
+ // C:
+ if is_valid_drive_letter(*c) {
+ return Some(Disk(c.to_ascii_uppercase()));
}
- return None;
}
+ None
}
/// Returns the first two path components with predicate `f`.