fast_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    if q.exists() {
66        fs::remove_file(&q)?;
67    }
68
69    match fs::hard_link(p, q) {
70        Ok(()) => Ok(LinkOrCopy::Link),
71        Err(_) => match fs::copy(p, q) {
72            Ok(_) => Ok(LinkOrCopy::Copy),
73            Err(e) => Err(e),
74        },
75    }
76}
77
78#[derive(Debug)]
79pub enum RenameOrCopyRemove {
80    Rename,
81    CopyRemove,
82}
83
84/// Rename `p` into `q`, preferring to use `rename` if possible.
85/// If `rename` fails (rename may fail for reasons such as crossing
86/// filesystem), fallback to copy & remove
87pub fn rename_or_copy_remove<P: AsRef<Path>, Q: AsRef<Path>>(
88    p: P,
89    q: Q,
90) -> io::Result<RenameOrCopyRemove> {
91    let p = p.as_ref();
92    let q = q.as_ref();
93    match fs::rename(p, q) {
94        Ok(()) => Ok(RenameOrCopyRemove::Rename),
95        Err(_) => match fs::copy(p, q) {
96            Ok(_) => {
97                fs::remove_file(p)?;
98                Ok(RenameOrCopyRemove::CopyRemove)
99            }
100            Err(e) => Err(e),
101        },
102    }
103}
104
105#[cfg(unix)]
106pub fn path_to_c_string(p: &Path) -> CString {
107    use std::ffi::OsStr;
108    use std::os::unix::ffi::OsStrExt;
109    let p: &OsStr = p.as_ref();
110    CString::new(p.as_bytes()).unwrap()
111}
112#[cfg(windows)]
113pub fn path_to_c_string(p: &Path) -> CString {
114    CString::new(p.to_str().unwrap()).unwrap()
115}
fast_rustc_ap_rustc_fs_util/lib.rs

fast_rustc_ap_rustc_fs_util/
lib.rs
