diff options
Diffstat (limited to 'src/libstd/sys/windows/path.rs')
| -rw-r--r-- | src/libstd/sys/windows/path.rs | 139 |
1 files changed, 76 insertions, 63 deletions
diff --git a/src/libstd/sys/windows/path.rs b/src/libstd/sys/windows/path.rs index 524f21f889b..dda3ed68cfc 100644 --- a/src/libstd/sys/windows/path.rs +++ b/src/libstd/sys/windows/path.rs @@ -2,6 +2,16 @@ use crate::ffi::OsStr; use crate::mem; use crate::path::Prefix; +#[cfg(test)] +mod tests; + +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) } } @@ -19,76 +29,79 @@ pub fn is_verbatim_sep(b: u8) -> bool { b == b'\\' } +// In most DOS systems, it is not possible to have more than 26 drive letters. +// See <https://en.wikipedia.org/wiki/Drive_letter_assignment#Common_assignments>. +pub fn is_valid_drive_letter(disk: u8) -> bool { + disk.is_ascii_alphabetic() +} + pub fn parse_prefix(path: &OsStr) -> Option<Prefix<'_>> { - use crate::path::Prefix::*; - 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 mut path = os_str_as_u8_slice(path); + use Prefix::{DeviceNS, Disk, Verbatim, VerbatimDisk, VerbatimUNC, UNC}; + + let path = os_str_as_u8_slice(path); - if path.starts_with(br"\\") { - // \\ - path = &path[2..]; - if path.starts_with(br"?\") { - // \\?\ - path = &path[2..]; - if path.starts_with(br"UNC\") { - // \\?\UNC\server\share - path = &path[4..]; - let (server, share) = match parse_two_comps(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), u8_slice_as_os_str(&[])), - }; - return Some(VerbatimUNC(server, share)); - } else { - // \\?\path - let idx = path.iter().position(|&b| b == b'\\'); - if idx == Some(2) && path[1] == b':' { - let c = path[0]; - if c.is_ascii() && (c as char).is_alphabetic() { - // \\?\C:\ path - return Some(VerbatimDisk(c.to_ascii_uppercase())); - } + // \\ + 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) })); } - let slice = &path[..idx.unwrap_or(path.len())]; - return Some(Verbatim(u8_slice_as_os_str(slice))); - } - } else if path.starts_with(b".\\") { - // \\.\path - path = &path[2..]; - let pos = path.iter().position(|&b| b == b'\\'); - let slice = &path[..pos.unwrap_or(path.len())]; - return Some(DeviceNS(u8_slice_as_os_str(slice))); - } - match parse_two_comps(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 path.get(1) == Some(&b':') { - // C: - let c = path[0]; - if c.is_ascii() && (c as char).is_alphabetic() { - 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; - } - - fn parse_two_comps(mut path: &[u8], f: fn(u8) -> bool) -> Option<(&[u8], &[u8])> { - let first = &path[..path.iter().position(|x| f(*x))?]; - path = &path[(first.len() + 1)..]; - let idx = path.iter().position(|x| f(*x)); - let second = &path[..idx.unwrap_or(path.len())]; - Some((first, second)) } + None } -pub const MAIN_SEP_STR: &str = "\\"; -pub const MAIN_SEP: char = '\\'; +/// Returns the first two path components with predicate `f`. +/// +/// The two components returned will be use by caller +/// to construct `VerbatimUNC` or `UNC` Windows path prefix. +/// +/// Returns [`None`] if there are no separators in path. +fn get_first_two_components(path: &[u8], f: fn(u8) -> bool) -> Option<(&[u8], &[u8])> { + let idx = path.iter().position(|&x| f(x))?; + // Panic safe + // The max `idx+1` is `path.len()` and `path[path.len()..]` is a valid index. + let (first, path) = (&path[..idx], &path[idx + 1..]); + let idx = path.iter().position(|&x| f(x)).unwrap_or(path.len()); + let second = &path[..idx]; + Some((first, second)) +} |