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
158
159
160
161
162

//! Run a command in bash, pretending to be a tty.
//!
//! This means that the command will assume that terminal colors and
//! other terminal features are available.
//!
//! ## Example
//!
//! ```
//! let output = fake_tty::bash_command("ls --color=auto").output().unwrap();
//! assert!(output.status.success());
//!
//! let _stdout: String = String::from_utf8(output.stdout).unwrap();
//! ```

use std::{iter, process};

/// Creates a command that is executed by bash, pretending to be a tty.
///
/// This means that the command will assume that terminal colors and
/// other terminal features are available.
pub fn bash_command(command: &str) -> process::Command {
    let script_command = make_script_command(&command);

    let mut command = process::Command::new("bash");
    command
        .args(&["-c", &script_command])
        .stdout(process::Stdio::piped())
        .stderr(process::Stdio::piped());

    command
}

/// Wraps the command in the `script` command that can execute it
/// pretending to be a tty.
///
/// This can be executed in two ways:
///  - by passing it to `bash -c <command>`
///    (you can use the `bash_command` function for this) or
///  - by running `bash` and piping the command to stdin,
///    followed with the command `exit`
///
/// ## Examples
///
/// Pass it to `bash -c <command>`:
///
/// ```
/// use std::process::{Command, Stdio};
/// use fake_tty::make_script_command;
///
/// let script_command = make_script_command("ls");
///
/// let output = Command::new("bash")
///     .args(&["-c", &script_command])
///     .stdout(Stdio::piped())
///     .stderr(Stdio::piped())
///     .output().unwrap();
///
/// assert!(output.status.success());
/// ```
///
/// Pipe it to `bash`:
///
/// ```
/// use std::process::{Command, Stdio};
/// use std::io::Write;
/// use fake_tty::make_script_command;
///
/// let mut script_command = make_script_command("ls");
/// script_command.push_str("\nexit");
///
/// let process = Command::new("bash")
///     .stdin(Stdio::piped())
///     .stdout(Stdio::piped())
///     .stderr(Stdio::piped())
///     .spawn()
///     .unwrap();
///
/// let mut stdin = process.stdin.as_ref().unwrap();
/// stdin.write_all(script_command.as_bytes()).unwrap();
/// let output = process.wait_with_output().unwrap();
///
/// assert!(output.status.success());
/// ```
pub fn make_script_command(command: &str) -> String {
    let escaped = escape_bash_string(command);

    #[cfg(target_os = "linux")]
    let script_command = format!("script -qec \"{}\" /dev/null", escaped);

    #[cfg(target_os = "macos")]
    let script_command = format!("script -q /dev/null \"{}\"", escaped);

    #[cfg(not(any(target_os = "linux", target_os = "macos")))]
    panic!("This platform is not supported");

    script_command
}

fn escape_bash_string(s: &str) -> String {
    s.chars().flat_map(escape_bash_string_char).collect()
}

fn escape_bash_string_char(c: char) -> impl Iterator<Item = char> {
    Some('\\')
        .filter(|_| matches!(c, '"' | '$' | '`' | '\\'))
        .into_iter()
        .chain(iter::once(c))
}

#[cfg(test)]
mod tests {
    use std::io::Write;
    use std::process;

    use crate::{bash_command, escape_bash_string, make_script_command};

    #[test]
    fn test_escaping() {
        assert_eq!(
            escape_bash_string(r#"Hello $`"' world!"#).as_str(),
            r#"Hello \$\`\"' world!"#
        );
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn test_script_wrapping() {
        assert_eq!(
            make_script_command(r#"echo "Hello $`' world!""#).as_str(),
            r#"script -qec "echo \"Hello \$\`' world!\"" /dev/null"#
        );
    }

    #[test]
    fn test_echo() {
        let output = bash_command(r#"echo "Hello \$\`' world!""#)
            .output()
            .unwrap();
        assert_eq!(to_string(output.stdout).trim_end(), r#"Hello $`' world!"#);
    }

    #[test]
    fn test_echo_custom() {
        let process = process::Command::new("bash")
            .stdin(process::Stdio::piped())
            .stdout(process::Stdio::piped())
            .stderr(process::Stdio::piped())
            .spawn()
            .unwrap();

        let mut stdin = process.stdin.as_ref().unwrap();
        stdin.write_all(br#"echo "Hello \$\`' world!""#).unwrap();
        let output = process.wait_with_output().unwrap();

        assert_eq!(to_string(output.stdout).trim_end(), r#"Hello $`' world!"#);
        assert_eq!(to_string(output.stderr), "");
    }

    fn to_string(v: Vec<u8>) -> String {
        String::from_utf8(v).unwrap()
    }
}