rustc_ap_rustc_fs_util/
lib.rs

1use std::ffi::CString;
2use std::fs;
3use std::io;
4use std::path::{Path, PathBuf};
5
6// Unfortunately, on windows, it looks like msvcrt.dll is silently translating
7// verbatim paths under the hood to non-verbatim paths! This manifests itself as
8// gcc looking like it cannot accept paths of the form `\\?\C:\...`, but the
9// real bug seems to lie in msvcrt.dll.
10//
11// Verbatim paths are generally pretty rare, but the implementation of
12// `fs::canonicalize` currently generates paths of this form, meaning that we're
13// going to be passing quite a few of these down to gcc, so we need to deal with
14// this case.
15//
16// For now we just strip the "verbatim prefix" of `\\?\` from the path. This
17// will probably lose information in some cases, but there's not a whole lot
18// more we can do with a buggy msvcrt...
19//
20// For some more information, see this comment:
21//   https://github.com/rust-lang/rust/issues/25505#issuecomment-102876737
22#[cfg(windows)]
23pub fn fix_windows_verbatim_for_gcc(p: &Path) -> PathBuf {
24    use std::ffi::OsString;
25    use std::path;
26    let mut components = p.components();
27    let prefix = match components.next() {
28        Some(path::Component::Prefix(p)) => p,
29        _ => return p.to_path_buf(),
30    };
31    match prefix.kind() {
32        path::Prefix::VerbatimDisk(disk) => {
33            let mut base = OsString::from(format!("{}:", disk as char));
34            base.push(components.as_path());
35            PathBuf::from(base)
36        }
37        path::Prefix::VerbatimUNC(server, share) => {
38            let mut base = OsString::from(r"\\");
39            base.push(server);
40            base.push(r"\");
41            base.push(share);
42            base.push(components.as_path());
43            PathBuf::from(base)
44        }
45        _ => p.to_path_buf(),
46    }
47}
48
49#[cfg(not(windows))]
50pub fn fix_windows_verbatim_for_gcc(p: &Path) -> PathBuf {
51    p.to_path_buf()
52}
53
54pub enum LinkOrCopy {
55    Link,
56    Copy,
57}
58
59/// Copies `p` into `q`, preferring to use hard-linking if possible. If
60/// `q` already exists, it is removed first.
61/// The result indicates which of the two operations has been performed.
62pub fn link_or_copy<P: AsRef<Path>, Q: AsRef<Path>>(p: P, q: Q) -> io::Result<LinkOrCopy> {
63    let p = p.as_ref();
64    let q = q.as_ref();
65    match fs::remove_file(&q) {
66        Ok(()) => (),
67        Err(err) if err.kind() == io::ErrorKind::NotFound => (),
68        Err(err) => return Err(err),
69    }
70
71    match fs::hard_link(p, q) {
72        Ok(()) => Ok(LinkOrCopy::Link),
73        Err(_) => match fs::copy(p, q) {
74            Ok(_) => Ok(LinkOrCopy::Copy),
75            Err(e) => Err(e),
76        },
77    }
78}
79
80#[cfg(unix)]
81pub fn path_to_c_string(p: &Path) -> CString {
82    use std::ffi::OsStr;
83    use std::os::unix::ffi::OsStrExt;
84    let p: &OsStr = p.as_ref();
85    CString::new(p.as_bytes()).unwrap()
86}
87#[cfg(windows)]
88pub fn path_to_c_string(p: &Path) -> CString {
89    CString::new(p.to_str().unwrap()).unwrap()
90}
rustc_ap_rustc_fs_util/lib.rs

rustc_ap_rustc_fs_util/
lib.rs
