rust/src/libextra/term.rs

// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Simple ANSI color library

#[allow(missing_doc)];


use std::io::{Decorator, Writer};

use std::os;
use terminfo::*;
use terminfo::searcher::open;
use terminfo::parser::compiled::{parse, msys_terminfo};
use terminfo::parm::{expand, Number, Variables};

// FIXME (#2807): Windows support.

pub mod color {
    pub type Color = u16;

    pub static BLACK:   Color = 0u16;
    pub static RED:     Color = 1u16;
    pub static GREEN:   Color = 2u16;
    pub static YELLOW:  Color = 3u16;
    pub static BLUE:    Color = 4u16;
    pub static MAGENTA: Color = 5u16;
    pub static CYAN:    Color = 6u16;
    pub static WHITE:   Color = 7u16;

    pub static BRIGHT_BLACK:   Color = 8u16;
    pub static BRIGHT_RED:     Color = 9u16;
    pub static BRIGHT_GREEN:   Color = 10u16;
    pub static BRIGHT_YELLOW:  Color = 11u16;
    pub static BRIGHT_BLUE:    Color = 12u16;
    pub static BRIGHT_MAGENTA: Color = 13u16;
    pub static BRIGHT_CYAN:    Color = 14u16;
    pub static BRIGHT_WHITE:   Color = 15u16;
}

pub mod attr {
    /// Terminal attributes for use with term.attr().
    /// Most attributes can only be turned on and must be turned off with term.reset().
    /// The ones that can be turned off explicitly take a boolean value.
    /// Color is also represented as an attribute for convenience.
    pub enum Attr {
        /// Bold (or possibly bright) mode
        Bold,
        /// Dim mode, also called faint or half-bright. Often not supported
        Dim,
        /// Italics mode. Often not supported
        Italic(bool),
        /// Underline mode
        Underline(bool),
        /// Blink mode
        Blink,
        /// Standout mode. Often implemented as Reverse, sometimes coupled with Bold
        Standout(bool),
        /// Reverse mode, inverts the foreground and background colors
        Reverse,
        /// Secure mode, also called invis mode. Hides the printed text
        Secure,
        /// Convenience attribute to set the foreground color
        ForegroundColor(super::color::Color),
        /// Convenience attribute to set the background color
        BackgroundColor(super::color::Color)
    }
}

fn cap_for_attr(attr: attr::Attr) -> &'static str {
    match attr {
        attr::Bold               => "bold",
        attr::Dim                => "dim",
        attr::Italic(true)       => "sitm",
        attr::Italic(false)      => "ritm",
        attr::Underline(true)    => "smul",
        attr::Underline(false)   => "rmul",
        attr::Blink              => "blink",
        attr::Standout(true)     => "smso",
        attr::Standout(false)    => "rmso",
        attr::Reverse            => "rev",
        attr::Secure             => "invis",
        attr::ForegroundColor(_) => "setaf",
        attr::BackgroundColor(_) => "setab"
    }
}

pub struct Terminal<T> {
    priv num_colors: u16,
    priv out: T,
    priv ti: ~TermInfo
}

impl<T: Writer> Terminal<T> {
    pub fn new(out: T) -> Result<Terminal<T>, ~str> {
        let term = match os::getenv("TERM") {
            Some(t) => t,
            None => return Err(~"TERM environment variable undefined")
        };

        let entry = open(term);
        if entry.is_err() {
            if "cygwin" == term { // msys terminal
                return Ok(Terminal {out: out, ti: msys_terminfo(), num_colors: 8});
            }
            return Err(entry.unwrap_err());
        }

        let ti = parse(entry.unwrap(), false);
        if ti.is_err() {
            return Err(ti.unwrap_err());
        }

        let inf = ti.unwrap();
        let nc = if inf.strings.find_equiv(&("setaf")).is_some()
                 && inf.strings.find_equiv(&("setab")).is_some() {
                     inf.numbers.find_equiv(&("colors")).map_default(0, |&n| n)
                 } else { 0 };

        return Ok(Terminal {out: out, ti: inf, num_colors: nc});
    }
    /// Sets the foreground color to the given color.
    ///
    /// If the color is a bright color, but the terminal only supports 8 colors,
    /// the corresponding normal color will be used instead.
    ///
    /// Returns true if the color was set, false otherwise.
    pub fn fg(&mut self, color: color::Color) -> bool {
        let color = self.dim_if_necessary(color);
        if self.num_colors > color {
            let s = expand(*self.ti.strings.find_equiv(&("setaf")).unwrap(),
                           [Number(color as int)], &mut Variables::new());
            if s.is_ok() {
                self.out.write(s.unwrap());
                return true
            } else {
                warn!("{}", s.unwrap_err());
            }
        }
        false
    }
    /// Sets the background color to the given color.
    ///
    /// If the color is a bright color, but the terminal only supports 8 colors,
    /// the corresponding normal color will be used instead.
    ///
    /// Returns true if the color was set, false otherwise.
    pub fn bg(&mut self, color: color::Color) -> bool {
        let color = self.dim_if_necessary(color);
        if self.num_colors > color {
            let s = expand(*self.ti.strings.find_equiv(&("setab")).unwrap(),
                           [Number(color as int)], &mut Variables::new());
            if s.is_ok() {
                self.out.write(s.unwrap());
                return true
            } else {
                warn!("{}", s.unwrap_err());
            }
        }
        false
    }

    /// Sets the given terminal attribute, if supported.
    /// Returns true if the attribute was supported, false otherwise.
    pub fn attr(&mut self, attr: attr::Attr) -> bool {
        match attr {
            attr::ForegroundColor(c) => self.fg(c),
            attr::BackgroundColor(c) => self.bg(c),
            _ => {
                let cap = cap_for_attr(attr);
                let parm = self.ti.strings.find_equiv(&cap);
                if parm.is_some() {
                    let s = expand(*parm.unwrap(), [], &mut Variables::new());
                    if s.is_ok() {
                        self.out.write(s.unwrap());
                        return true
                    } else {
                        warn!("{}", s.unwrap_err());
                    }
                }
                false
            }
        }
    }

    /// Returns whether the given terminal attribute is supported.
    pub fn supports_attr(&self, attr: attr::Attr) -> bool {
        match attr {
            attr::ForegroundColor(_) | attr::BackgroundColor(_) => {
                self.num_colors > 0
            }
            _ => {
                let cap = cap_for_attr(attr);
                self.ti.strings.find_equiv(&cap).is_some()
            }
        }
    }

    /// Resets all terminal attributes and color to the default.
    pub fn reset(&mut self) {
        let mut cap = self.ti.strings.find_equiv(&("sgr0"));
        if cap.is_none() {
            // are there any terminals that have color/attrs and not sgr0?
            // Try falling back to sgr, then op
            cap = self.ti.strings.find_equiv(&("sgr"));
            if cap.is_none() {
                cap = self.ti.strings.find_equiv(&("op"));
            }
        }
        let s = cap.map_default(Err(~"can't find terminfo capability `sgr0`"), |op| {
            expand(*op, [], &mut Variables::new())
        });
        if s.is_ok() {
            self.out.write(s.unwrap());
        } else if self.num_colors > 0 {
            warn!("{}", s.unwrap_err());
        } else {
            // if we support attributes but not color, it would be nice to still warn!()
            // but it's not worth testing all known attributes just for this.
            debug!("{}", s.unwrap_err());
        }
    }

    fn dim_if_necessary(&self, color: color::Color) -> color::Color {
        if color >= self.num_colors && color >= 8 && color < 16 {
            color-8
        } else { color }
    }
}

impl<T: Writer> Decorator<T> for Terminal<T> {
    fn inner(self) -> T {
        self.out
    }

    fn inner_ref<'a>(&'a self) -> &'a T {
        &self.out
    }

    fn inner_mut_ref<'a>(&'a mut self) -> &'a mut T {
        &mut self.out
    }
}

impl<T: Writer> Writer for Terminal<T> {
    fn write(&mut self, buf: &[u8]) {
        self.out.write(buf);
    }

    fn flush(&mut self) {
        self.out.flush();
    }
}