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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

#![allow(dead_code)]
#![unstable(feature = "process_internals", issue = "none")]

use crate::collections::BTreeMap;
use crate::env;
use crate::ffi::{OsStr, OsString};
use crate::fmt;
use crate::io;
use crate::sys::pipe::read2;
use crate::sys::process::{EnvKey, ExitStatus, Process, StdioPipes};

// Stores a set of changes to an environment
#[derive(Clone)]
pub struct CommandEnv {
    clear: bool,
    saw_path: bool,
    vars: BTreeMap<EnvKey, Option<OsString>>,
}

impl Default for CommandEnv {
    fn default() -> Self {
        CommandEnv { clear: false, saw_path: false, vars: Default::default() }
    }
}

impl fmt::Debug for CommandEnv {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut debug_command_env = f.debug_struct("CommandEnv");
        debug_command_env.field("clear", &self.clear).field("vars", &self.vars);
        debug_command_env.finish()
    }
}

impl CommandEnv {
    // Capture the current environment with these changes applied
    pub fn capture(&self) -> BTreeMap<EnvKey, OsString> {
        let mut result = BTreeMap::<EnvKey, OsString>::new();
        if !self.clear {
            for (k, v) in env::vars_os() {
                result.insert(k.into(), v);
            }
        }
        for (k, maybe_v) in &self.vars {
            if let &Some(ref v) = maybe_v {
                result.insert(k.clone(), v.clone());
            } else {
                result.remove(k);
            }
        }
        result
    }

    pub fn is_unchanged(&self) -> bool {
        !self.clear && self.vars.is_empty()
    }

    pub fn capture_if_changed(&self) -> Option<BTreeMap<EnvKey, OsString>> {
        if self.is_unchanged() { None } else { Some(self.capture()) }
    }

    // The following functions build up changes
    pub fn set(&mut self, key: &OsStr, value: &OsStr) {
        let key = EnvKey::from(key);
        self.maybe_saw_path(&key);
        self.vars.insert(key, Some(value.to_owned()));
    }

    pub fn remove(&mut self, key: &OsStr) {
        let key = EnvKey::from(key);
        self.maybe_saw_path(&key);
        if self.clear {
            self.vars.remove(&key);
        } else {
            self.vars.insert(key, None);
        }
    }

    pub fn clear(&mut self) {
        self.clear = true;
        self.vars.clear();
    }

    pub fn have_changed_path(&self) -> bool {
        self.saw_path || self.clear
    }

    fn maybe_saw_path(&mut self, key: &EnvKey) {
        if !self.saw_path && key == "PATH" {
            self.saw_path = true;
        }
    }

    pub fn iter(&self) -> CommandEnvs<'_> {
        let iter = self.vars.iter();
        CommandEnvs { iter }
    }
}

/// An iterator over the command environment variables.
///
/// This struct is created by
/// [`Command::get_envs`][crate::process::Command::get_envs]. See its
/// documentation for more.
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[stable(feature = "command_access", since = "1.57.0")]
#[derive(Debug)]
pub struct CommandEnvs<'a> {
    iter: crate::collections::btree_map::Iter<'a, EnvKey, Option<OsString>>,
}

#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> Iterator for CommandEnvs<'a> {
    type Item = (&'a OsStr, Option<&'a OsStr>);
    fn next(&mut self) -> Option<Self::Item> {
        self.iter.next().map(|(key, value)| (key.as_ref(), value.as_deref()))
    }
    fn size_hint(&self) -> (usize, Option<usize>) {
        self.iter.size_hint()
    }
}

#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> ExactSizeIterator for CommandEnvs<'a> {
    fn len(&self) -> usize {
        self.iter.len()
    }
    fn is_empty(&self) -> bool {
        self.iter.is_empty()
    }
}

pub fn wait_with_output(
    mut process: Process,
    mut pipes: StdioPipes,
) -> io::Result<(ExitStatus, Vec<u8>, Vec<u8>)> {
    drop(pipes.stdin.take());

    let (mut stdout, mut stderr) = (Vec::new(), Vec::new());
    match (pipes.stdout.take(), pipes.stderr.take()) {
        (None, None) => {}
        (Some(out), None) => {
            let res = out.read_to_end(&mut stdout);
            res.unwrap();
        }
        (None, Some(err)) => {
            let res = err.read_to_end(&mut stderr);
            res.unwrap();
        }
        (Some(out), Some(err)) => {
            let res = read2(out, &mut stdout, err, &mut stderr);
            res.unwrap();
        }
    }

    let status = process.wait()?;
    Ok((status, stdout, stderr))
}