[go: up one dir, main page]

cc 1.2.13

A build-time dependency for Cargo build scripts to assist in invoking the native C compiler to compile native C code into a static archive to be linked into Rust code.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130

use std::{
    cell::UnsafeCell,
    ffi::OsStr,
    fmt::{self, Write},
    marker::PhantomData,
    mem::MaybeUninit,
    panic::{RefUnwindSafe, UnwindSafe},
    path::Path,
    sync::Once,
};

pub(super) struct JoinOsStrs<'a, T> {
    pub(super) slice: &'a [T],
    pub(super) delimiter: char,
}

impl<T> fmt::Display for JoinOsStrs<'_, T>
where
    T: AsRef<OsStr>,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let len = self.slice.len();
        for (index, os_str) in self.slice.iter().enumerate() {
            // TODO: Use OsStr::display once it is stablised,
            // Path and OsStr has the same `Display` impl
            write!(f, "{}", Path::new(os_str).display())?;
            if index + 1 < len {
                f.write_char(self.delimiter)?;
            }
        }
        Ok(())
    }
}

pub(super) struct OptionOsStrDisplay<T>(pub(super) Option<T>);

impl<T> fmt::Display for OptionOsStrDisplay<T>
where
    T: AsRef<OsStr>,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // TODO: Use OsStr::display once it is stablised
        // Path and OsStr has the same `Display` impl
        if let Some(os_str) = self.0.as_ref() {
            write!(f, "Some({})", Path::new(os_str).display())
        } else {
            f.write_str("None")
        }
    }
}

pub(crate) struct OnceLock<T> {
    once: Once,
    value: UnsafeCell<MaybeUninit<T>>,
    _marker: PhantomData<T>,
}

impl<T> Default for OnceLock<T> {
    fn default() -> Self {
        Self::new()
    }
}

impl<T> OnceLock<T> {
    pub(crate) const fn new() -> Self {
        Self {
            once: Once::new(),
            value: UnsafeCell::new(MaybeUninit::uninit()),
            _marker: PhantomData,
        }
    }

    #[inline]
    fn is_initialized(&self) -> bool {
        self.once.is_completed()
    }

    unsafe fn get_unchecked(&self) -> &T {
        debug_assert!(self.is_initialized());
        #[allow(clippy::needless_borrow)]
        #[allow(unused_unsafe)]
        unsafe {
            (&*self.value.get()).assume_init_ref()
        }
    }

    pub(crate) fn get_or_init(&self, f: impl FnOnce() -> T) -> &T {
        self.once.call_once(|| {
            unsafe { &mut *self.value.get() }.write(f());
        });
        unsafe { self.get_unchecked() }
    }

    pub(crate) fn get(&self) -> Option<&T> {
        if self.is_initialized() {
            // Safe b/c checked is_initialized
            Some(unsafe { self.get_unchecked() })
        } else {
            None
        }
    }
}

impl<T: fmt::Debug> fmt::Debug for OnceLock<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut d = f.debug_tuple("OnceLock");
        match self.get() {
            Some(v) => d.field(v),
            None => d.field(&format_args!("<uninit>")),
        };
        d.finish()
    }
}

unsafe impl<T: Sync + Send> Sync for OnceLock<T> {}
unsafe impl<T: Send> Send for OnceLock<T> {}

impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceLock<T> {}
impl<T: UnwindSafe> UnwindSafe for OnceLock<T> {}

impl<T> Drop for OnceLock<T> {
    #[inline]
    fn drop(&mut self) {
        if self.once.is_completed() {
            // SAFETY: The cell is initialized and being dropped, so it can't
            // be accessed again.
            unsafe { self.value.get_mut().assume_init_drop() };
        }
    }
}