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
use std::collections::HashMap;
use std::env;
use std::fs::*;
use std::io::{BufReader, Read, Write};
use std::path::*;
pub struct EnvCache {
entries: HashMap<String, String>,
}
fn cache_path() -> PathBuf {
Path::new(&env::var("OUT_DIR").unwrap()).join("envcache.config")
}
impl EnvCache {
pub fn new() -> Self {
let cache_path = cache_path();
let mut entries = HashMap::new();
if let Ok(file) = File::open(cache_path) {
let mut f = BufReader::new(file);
let mut string = String::new();
f.read_to_string(&mut string).unwrap();
let mut index = 0;
while index < string.len() {
let env_len = string[index..index + 8].parse::<u32>().unwrap() as usize;
index += 8;
let env = &string[index..index + env_len];
index += env_len;
let val_len = string[index..index + 8].parse::<u32>().unwrap() as usize;
index += 8;
let val = &string[index..index + val_len];
index += val_len;
entries.insert(env.to_string(), val.to_string());
}
}
Self { entries }
}
pub fn cache(&mut self, env: &str) {
if let Ok(var) = env::var(env) {
self.entries.insert(env.to_string(), var);
}
}
}
impl Default for EnvCache {
fn default() -> Self {
Self::new()
}
}
impl Drop for EnvCache {
fn drop(&mut self) {
let cache_path = cache_path();
if let Ok(mut file) = File::create(cache_path) {
for (key, val) in self.entries.iter() {
println!("cargo:rerun-if-env-changed={}", key);
println!("cargo:rustc-env={}={}", key, val);
write!(file, "{:08x}{}{:08x}{}", key.len(), key, val.len(), val).unwrap();
}
}
}
}