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use duplex::Duplex;
use std::io::{Read, Write};
/// A trait for devices which may be connected to terminals.
pub trait Terminal {}
/// An extension trait for input streams connected to terminals.
pub trait ReadTerminal: Read + Terminal {
/// Test whether the input is being sent a line at a time.
fn is_line_by_line(&self) -> bool;
/// Test whether the input is connected to a terminal.
///
/// Also known as `isatty`.
fn is_input_terminal(&self) -> bool;
}
/// An extension trait for output streams connected to terminals.
pub trait WriteTerminal: Write + Terminal {
/// Test whether color should be used on this terminal by default. This
/// includes both whether color is supported and whether the user has
/// not indicated a preference otherwise.
fn color_default(&self) -> bool {
self.color_support() != TerminalColorSupport::Monochrome && self.color_preference()
}
/// Test whether this output stream supports color control codes.
fn color_support(&self) -> TerminalColorSupport;
/// Test whether the user has indicated a preference for color output by
/// default. Respects the `NO_COLOR` environment variable where applicable.
fn color_preference(&self) -> bool;
/// Test whether the output is connected to a terminal.
///
/// Also known as `isatty`.
fn is_output_terminal(&self) -> bool;
}
/// An extension trait for input/output streams connected to terminals.
pub trait DuplexTerminal: ReadTerminal + WriteTerminal + Duplex {
/// Test whether both the input stream and output streams are connected to
/// terminals.
///
/// Also known as `isatty`.
fn is_terminal(&self) -> bool {
self.is_input_terminal() && self.is_output_terminal()
}
}
/// Color support level, ranging from monochrome (color not supported) to
/// 24-bit true color.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum TerminalColorSupport {
/// Color is not supported.
Monochrome,
/// Classic ANSI 8 colors. Sometimes extendable to 16 by using bold.
Classic8,
/// 256 colors with a "color cube". See [Wikipedia] for details.
///
/// [Wikipedia]: https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
ColorCube256,
/// 24-bit "true color" support. See [Wikipedia] for details.
///
/// [Wikipedia]: https://en.wikipedia.org/wiki/ANSI_escape_code#24-bit
TrueColor,
}
impl Default for TerminalColorSupport {
#[inline]
fn default() -> Self {
Self::Monochrome
}
}