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
163

//! This module exports utilities related to terminal's standard input and
//! output at a raw level.

use crossterm::Command;
use std::{
    fmt,
    pin::Pin,
    task::{Context, Poll},
};
use tokio::{
    io,
    io::{AsyncWrite, AsyncWriteExt, Stdout as TokioStdout},
    sync::{Mutex, MutexGuard},
};

/// A centralized lock to a standard output handle.
#[derive(Debug)]
pub struct Stdout {
    /// A lock to tokio's stdout.
    inner: Mutex<TokioStdout>,
}

impl Stdout {
    /// Creates a new centralized stdout lock. You should NOT call this
    /// function if there is already an active centralized lock to the Stdout.
    /// You shouldn't also write to stdout through other means, such as
    /// std's `println!`.
    pub fn new() -> Stdout {
        Self { inner: Mutex::new(io::stdout()) }
    }

    /// Locks this centralized lock to the standard output, and acquire a locked
    /// stdout.
    pub async fn lock<'stdout>(&'stdout self) -> LockedStdout<'stdout> {
        LockedStdout { guard: self.inner.lock().await }
    }

    /// Tries to lock this centralized lock to the standard output, without
    /// blocking, and acquire a locked stdout. Returns `None` if lock failed.
    pub fn try_lock(&self) -> Option<LockedStdout> {
        self.inner.try_lock().ok().map(|guard| LockedStdout { guard })
    }

    /// Locks the stdout and writes and flushes everything in the given buffer.
    pub async fn write_and_flush(&self, buf: &[u8]) -> Result<(), io::Error> {
        self.lock().await.write_and_flush(buf).await
    }
}

/// A locked standard output handle.
#[derive(Debug)]
pub struct LockedStdout<'stdout> {
    /// Guard of tokio's Mutex.
    guard: MutexGuard<'stdout, TokioStdout>,
}

impl<'stdout> LockedStdout<'stdout> {
    pub async fn write_and_flush(
        &mut self,
        buf: &[u8],
    ) -> Result<(), io::Error> {
        self.write_all(buf).await?;
        self.flush().await?;
        Ok(())
    }
}

impl<'stdout> AsyncWrite for LockedStdout<'stdout> {
    fn poll_write(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<Result<usize, io::Error>> {
        Pin::new(&mut *self.as_mut().guard).poll_write(cx, buf)
    }

    fn poll_flush(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Result<(), io::Error>> {
        Pin::new(&mut *self.as_mut().guard).as_mut().poll_flush(cx)
    }

    fn poll_shutdown(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Result<(), io::Error>> {
        Pin::new(&mut *self.as_mut().guard).as_mut().poll_shutdown(cx)
    }
}

/// Saves the screen previous the application.
#[cfg(windows)]
pub fn save_screen(buf: &mut String) -> fmt::Result {
    if crossterm::terminal::EnterAlternateScreen.is_ansi_code_supported() {
        write!(
            buf,
            "{}",
            crossterm::terminal::EnterAlternateScreen.ansi_code()
        )?;
    }
    Ok(())
}

/// Saves the screen previous the application.
#[cfg(unix)]
pub fn save_screen(buf: &mut String) -> fmt::Result {
    crossterm::terminal::EnterAlternateScreen.write_ansi(buf)?;
    Ok(())
}

/// Restores the screen previous the application.
#[cfg(windows)]
pub fn restore_screen(buf: &mut String) -> fmt::Result {
    if crossterm::terminal::LeaveAlternateScreen.is_ansi_code_supported() {
        crossterm::terminal::LeaveAlternateScreen.write_ansi(buf)?;
    }
    Ok(())
}

/// Restores the screen previous the application.
#[cfg(unix)]
pub fn restore_screen(buf: &mut String) -> fmt::Result {
    crossterm::terminal::LeaveAlternateScreen.write_ansi(buf)?;
    Ok(())
}

#[cfg(windows)]
/// Best-effort function to restore the terminal in a panic.
pub fn emergency_restore() {
    let _ = crossterm::terminal::disable_raw_mode();
    print!("{}", crossterm::cursor::Show);
    print!(
        "{}",
        crossterm::style::SetBackgroundColor(crossterm::style::Color::Reset)
    );
    print!(
        "{}",
        crossterm::style::SetForegroundColor(crossterm::style::Color::Reset)
    );
    if crossterm::terminal::LeaveAlternateScreen.is_ansi_code_supported() {
        print!("{}", crossterm::terminal::LeaveAlternateScreen.ansi_code());
    }
    println!();
}

#[cfg(unix)]
/// Best-effort function to restore the terminal in a panic.
pub fn emergency_restore() {
    let _ = crossterm::terminal::disable_raw_mode();
    print!("{}", crossterm::cursor::Show);
    print!(
        "{}",
        crossterm::style::SetBackgroundColor(crossterm::style::Color::Reset)
    );
    print!(
        "{}",
        crossterm::style::SetForegroundColor(crossterm::style::Color::Reset)
    );
    let mut buf = String::new();
    let _ = crossterm::terminal::LeaveAlternateScreen.write_ansi(&mut buf);
    println!("{}", buf);
}