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
|
//! File and package management.
use std::collections::HashMap;
use std::fmt::{self, Debug, Formatter};
use std::sync::RwLock;
use once_cell::sync::Lazy;
use crate::package::PackageSpec;
use crate::VirtualPath;
/// The global package-path interner.
static INTERNER: Lazy<RwLock<Interner>> =
Lazy::new(|| RwLock::new(Interner { to_id: HashMap::new(), from_id: Vec::new() }));
/// A package-path interner.
struct Interner {
to_id: HashMap<Pair, FileId>,
from_id: Vec<Pair>,
}
/// An interned pair of a package specification and a path.
type Pair = &'static (Option<PackageSpec>, VirtualPath);
/// Identifies a file in a project or package.
///
/// This type is globally interned and thus cheap to copy, compare, and hash.
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct FileId(u16);
impl FileId {
/// Create a new interned file specification.
///
/// The path must start with a `/` or this function will panic.
/// Note that the path is normalized before interning.
#[track_caller]
pub fn new(package: Option<PackageSpec>, path: VirtualPath) -> Self {
// Try to find an existing entry that we can reuse.
//
// We could check with just a read lock, but if the pair is not yet
// present, we would then need to recheck after acquiring a write lock,
// which is probably not worth it.
let pair = (package, path);
let mut interner = INTERNER.write().unwrap();
if let Some(&id) = interner.to_id.get(&pair) {
return id;
}
// Create a new entry forever by leaking the pair. We can't leak more
// than 2^16 pair (and typically will leak a lot less), so its not a
// big deal.
let num = interner.from_id.len().try_into().expect("out of file ids");
let id = FileId(num);
let leaked = Box::leak(Box::new(pair));
interner.to_id.insert(leaked, id);
interner.from_id.push(leaked);
id
}
/// Create a new unique ("fake") file specification, which is not
/// accessible by path.
///
/// Caution: the ID returned by this method is the *only* identifier of the
/// file, constructing a file ID with a path will *not* reuse the ID even
/// if the path is the same. This method should only be used for generating
/// "virtual" file ids such as content read from stdin.
#[track_caller]
pub fn new_fake(path: VirtualPath) -> Self {
let mut interner = INTERNER.write().unwrap();
let num = interner.from_id.len().try_into().expect("out of file ids");
let id = FileId(num);
let leaked = Box::leak(Box::new((None, path)));
interner.from_id.push(leaked);
id
}
/// The package the file resides in, if any.
pub fn package(&self) -> Option<&'static PackageSpec> {
self.pair().0.as_ref()
}
/// The absolute and normalized path to the file _within_ the project or
/// package.
pub fn vpath(&self) -> &'static VirtualPath {
&self.pair().1
}
/// Resolve a file location relative to this file.
pub fn join(self, path: &str) -> Self {
Self::new(self.package().cloned(), self.vpath().join(path))
}
/// The same file location, but with a different extension.
pub fn with_extension(&self, extension: &str) -> Self {
Self::new(self.package().cloned(), self.vpath().with_extension(extension))
}
/// Construct from a raw number.
pub(crate) const fn from_raw(v: u16) -> Self {
Self(v)
}
/// Extract the raw underlying number.
pub(crate) const fn into_raw(self) -> u16 {
self.0
}
/// Get the static pair.
fn pair(&self) -> Pair {
INTERNER.read().unwrap().from_id[usize::from(self.0)]
}
}
impl Debug for FileId {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
let vpath = self.vpath();
match self.package() {
Some(package) => write!(f, "{package:?}{vpath:?}"),
None => write!(f, "{vpath:?}"),
}
}
}
|
