terminal 0.2.1

Unified API over different TUI libraries.
Documentation 
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

use std::{io, io::Write};

use crossterm::{
    cursor, event, style, terminal,
    terminal::{disable_raw_mode, enable_raw_mode},
    ExecutableCommand, QueueableCommand,
};

use crate::{backend::Backend, error, error::ErrorKind, Action, Event, Retrieved, Value};

pub struct BackendImpl<W: Write> {
    // The internal buffer on which operations are performed and written to.
    buffer: W,
    // Crossterm panics if we disable the mouse event capture before we enabled it.
    // We need to check in the `drop` if we enabled it to prevent this.
    // Should be fixed in later crossterm releases.
    mouse_capture_enabled: bool,
}

impl<W: Write> Backend<W> for BackendImpl<W> {
    fn create(buffer: W) -> BackendImpl<W> {
        BackendImpl {
            buffer,
            mouse_capture_enabled: false,
        }
    }

    fn act(&mut self, action: Action) -> error::Result<()> {
        self.batch(action)?;
        self.flush_batch()
    }

    #[allow(clippy::cognitive_complexity)]
    fn batch(&mut self, action: Action) -> error::Result<()> {
        let buffer = &mut self.buffer;

        let _ = match action {
            Action::MoveCursorTo(column, row) => buffer.queue(cursor::MoveTo(column, row))?,
            Action::HideCursor => buffer.queue(cursor::Hide)?,
            Action::ShowCursor => buffer.queue(cursor::Show)?,
            Action::EnableBlinking => buffer.queue(cursor::EnableBlinking)?,
            Action::DisableBlinking => buffer.queue(cursor::DisableBlinking)?,
            Action::ClearTerminal(clear_type) => {
                buffer.queue(terminal::Clear(terminal::ClearType::from(clear_type)))?
            }
            Action::SetTerminalSize(column, row) => buffer.queue(terminal::SetSize(column, row))?,
            Action::ScrollUp(rows) => buffer.queue(terminal::ScrollUp(rows))?,
            Action::ScrollDown(rows) => buffer.queue(terminal::ScrollDown(rows))?,
            Action::EnterAlternateScreen => {
                buffer.queue(terminal::EnterAlternateScreen)?;
                buffer
            }
            Action::LeaveAlternateScreen => {
                buffer.queue(terminal::LeaveAlternateScreen)?;
                buffer
            }
            Action::SetForegroundColor(color) => {
                buffer.queue(style::SetForegroundColor(style::Color::from(color)))?
            }
            Action::SetBackgroundColor(color) => {
                buffer.queue(style::SetBackgroundColor(style::Color::from(color)))?
            }
            Action::SetAttribute(attr) => {
                buffer.queue(style::SetAttribute(style::Attribute::from(attr)))?
            }
            Action::ResetColor => buffer.queue(style::ResetColor)?,
            Action::EnableRawMode => {
                enable_raw_mode()?;
                return Ok(());
            }
            Action::DisableRawMode => {
                disable_raw_mode()?;
                return Ok(());
            }
            Action::EnableMouseCapture => {
                self.mouse_capture_enabled = true;
                buffer.queue(event::EnableMouseCapture)?
            }
            Action::DisableMouseCapture => {
                self.mouse_capture_enabled = false;
                buffer.queue(event::DisableMouseCapture)?
            }
        };

        Ok(())
    }

    fn flush_batch(&mut self) -> error::Result<()> {
        self.buffer
            .flush()
            .map_err(|_| ErrorKind::FlushingBatchFailed)
    }

    fn get(&self, retrieve_operation: Value) -> error::Result<Retrieved> {
        Ok(match retrieve_operation {
            Value::TerminalSize => {
                let size = terminal::size()?;
                Retrieved::TerminalSize(size.0, size.1)
            }
            Value::CursorPosition => {
                let position = cursor::position()?;
                Retrieved::CursorPosition(position.0, position.1)
            }
            Value::Event(duration) => {
                if let Some(duration) = duration {
                    if event::poll(duration)? {
                        let event = event::read()?;
                        Retrieved::Event(Some(Event::from(event)))
                    } else {
                        Retrieved::Event(None)
                    }
                } else {
                    let event = event::read()?;
                    Retrieved::Event(Some(Event::from(event)))
                }
            }
        })
    }
}

impl<W: Write> Drop for BackendImpl<W> {
    fn drop(&mut self) {
        io::stdout()
            .execute(terminal::LeaveAlternateScreen)
            .unwrap();

        disable_raw_mode().unwrap();

        if self.mouse_capture_enabled {
            io::stdout().execute(event::DisableMouseCapture).unwrap();
        }
    }
}

impl<W: Write> Write for BackendImpl<W> {
    fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
        self.buffer.write(buf)
    }

    fn flush(&mut self) -> Result<(), io::Error> {
        self.buffer.flush()
    }
}