ansi_term/
display.rs

1use std::borrow::Cow;
2use std::fmt;
3use std::io;
4use std::ops::Deref;
5
6use ansi::RESET;
7use difference::Difference;
8use style::{Style, Colour};
9use write::AnyWrite;
10
11
12/// An `ANSIGenericString` includes a generic string type and a `Style` to
13/// display that string.  `ANSIString` and `ANSIByteString` are aliases for
14/// this type on `str` and `\[u8]`, respectively.
15#[derive(PartialEq, Debug)]
16pub struct ANSIGenericString<'a, S: 'a + ToOwned + ?Sized>
17where <S as ToOwned>::Owned: fmt::Debug {
18    style: Style,
19    string: Cow<'a, S>,
20}
21
22
23/// Cloning an `ANSIGenericString` will clone its underlying string.
24///
25/// # Examples
26///
27/// ```
28/// use ansi_term::ANSIString;
29///
30/// let plain_string = ANSIString::from("a plain string");
31/// let clone_string = plain_string.clone();
32/// assert_eq!(clone_string, plain_string);
33/// ```
34impl<'a, S: 'a + ToOwned + ?Sized> Clone for ANSIGenericString<'a, S>
35where <S as ToOwned>::Owned: fmt::Debug {
36    fn clone(&self) -> ANSIGenericString<'a, S> {
37        ANSIGenericString {
38            style: self.style,
39            string: self.string.clone(),
40        }
41    }
42}
43
44// You might think that the hand-written Clone impl above is the same as the
45// one that gets generated with #[derive]. But it’s not *quite* the same!
46//
47// `str` is not Clone, and the derived Clone implementation puts a Clone
48// constraint on the S type parameter (generated using --pretty=expanded):
49//
50//                  ↓_________________↓
51//     impl <'a, S: ::std::clone::Clone + 'a + ToOwned + ?Sized> ::std::clone::Clone
52//     for ANSIGenericString<'a, S> where
53//     <S as ToOwned>::Owned: fmt::Debug { ... }
54//
55// This resulted in compile errors when you tried to derive Clone on a type
56// that used it:
57//
58//     #[derive(PartialEq, Debug, Clone, Default)]
59//     pub struct TextCellContents(Vec<ANSIString<'static>>);
60//                                 ^^^^^^^^^^^^^^^^^^^^^^^^^
61//     error[E0277]: the trait `std::clone::Clone` is not implemented for `str`
62//
63// The hand-written impl above can ignore that constraint and still compile.
64
65
66
67/// An ANSI String is a string coupled with the `Style` to display it
68/// in a terminal.
69///
70/// Although not technically a string itself, it can be turned into
71/// one with the `to_string` method.
72///
73/// # Examples
74///
75/// ```
76/// use ansi_term::ANSIString;
77/// use ansi_term::Colour::Red;
78///
79/// let red_string = Red.paint("a red string");
80/// println!("{}", red_string);
81/// ```
82///
83/// ```
84/// use ansi_term::ANSIString;
85///
86/// let plain_string = ANSIString::from("a plain string");
87/// assert_eq!(&*plain_string, "a plain string");
88/// ```
89pub type ANSIString<'a> = ANSIGenericString<'a, str>;
90
91/// An `ANSIByteString` represents a formatted series of bytes.  Use
92/// `ANSIByteString` when styling text with an unknown encoding.
93pub type ANSIByteString<'a> = ANSIGenericString<'a, [u8]>;
94
95impl<'a, I, S: 'a + ToOwned + ?Sized> From<I> for ANSIGenericString<'a, S>
96where I: Into<Cow<'a, S>>,
97      <S as ToOwned>::Owned: fmt::Debug {
98    fn from(input: I) -> ANSIGenericString<'a, S> {
99        ANSIGenericString {
100            string: input.into(),
101            style:  Style::default(),
102        }
103    }
104}
105
106impl<'a, S: 'a + ToOwned + ?Sized> ANSIGenericString<'a, S>
107    where <S as ToOwned>::Owned: fmt::Debug {
108
109    /// Directly access the style
110    pub fn style_ref(&self) -> &Style {
111        &self.style
112    }
113
114    /// Directly access the style mutably
115    pub fn style_ref_mut(&mut self) -> &mut Style {
116        &mut self.style
117    }
118}
119
120impl<'a, S: 'a + ToOwned + ?Sized> Deref for ANSIGenericString<'a, S>
121where <S as ToOwned>::Owned: fmt::Debug {
122    type Target = S;
123
124    fn deref(&self) -> &S {
125        self.string.deref()
126    }
127}
128
129
130/// A set of `ANSIGenericString`s collected together, in order to be
131/// written with a minimum of control characters.
132#[derive(Debug, PartialEq)]
133pub struct ANSIGenericStrings<'a, S: 'a + ToOwned + ?Sized>
134    (pub &'a [ANSIGenericString<'a, S>])
135    where <S as ToOwned>::Owned: fmt::Debug, S: PartialEq;
136
137/// A set of `ANSIString`s collected together, in order to be written with a
138/// minimum of control characters.
139pub type ANSIStrings<'a> = ANSIGenericStrings<'a, str>;
140
141/// A function to construct an `ANSIStrings` instance.
142#[allow(non_snake_case)]
143pub fn ANSIStrings<'a>(arg: &'a [ANSIString<'a>]) -> ANSIStrings<'a> {
144    ANSIGenericStrings(arg)
145}
146
147/// A set of `ANSIByteString`s collected together, in order to be
148/// written with a minimum of control characters.
149pub type ANSIByteStrings<'a> = ANSIGenericStrings<'a, [u8]>;
150
151/// A function to construct an `ANSIByteStrings` instance.
152#[allow(non_snake_case)]
153pub fn ANSIByteStrings<'a>(arg: &'a [ANSIByteString<'a>]) -> ANSIByteStrings<'a> {
154    ANSIGenericStrings(arg)
155}
156
157
158// ---- paint functions ----
159
160impl Style {
161
162    /// Paints the given text with this colour, returning an ANSI string.
163    #[must_use]
164    pub fn paint<'a, I, S: 'a + ToOwned + ?Sized>(self, input: I) -> ANSIGenericString<'a, S>
165    where I: Into<Cow<'a, S>>,
166          <S as ToOwned>::Owned: fmt::Debug {
167        ANSIGenericString {
168            string: input.into(),
169            style:  self,
170        }
171    }
172}
173
174
175impl Colour {
176
177    /// Paints the given text with this colour, returning an ANSI string.
178    /// This is a short-cut so you don’t have to use `Blue.normal()` just
179    /// to get blue text.
180    ///
181    /// ```
182    /// use ansi_term::Colour::Blue;
183    /// println!("{}", Blue.paint("da ba dee"));
184    /// ```
185    #[must_use]
186    pub fn paint<'a, I, S: 'a + ToOwned + ?Sized>(self, input: I) -> ANSIGenericString<'a, S>
187    where I: Into<Cow<'a, S>>,
188          <S as ToOwned>::Owned: fmt::Debug {
189        ANSIGenericString {
190            string: input.into(),
191            style:  self.normal(),
192        }
193    }
194}
195
196
197// ---- writers for individual ANSI strings ----
198
199impl<'a> fmt::Display for ANSIString<'a> {
200    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
201        let w: &mut fmt::Write = f;
202        self.write_to_any(w)
203    }
204}
205
206impl<'a> ANSIByteString<'a> {
207    /// Write an `ANSIByteString` to an `io::Write`.  This writes the escape
208    /// sequences for the associated `Style` around the bytes.
209    pub fn write_to<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
210        let w: &mut io::Write = w;
211        self.write_to_any(w)
212    }
213}
214
215impl<'a, S: 'a + ToOwned + ?Sized> ANSIGenericString<'a, S>
216where <S as ToOwned>::Owned: fmt::Debug, &'a S: AsRef<[u8]> {
217    fn write_to_any<W: AnyWrite<wstr=S> + ?Sized>(&self, w: &mut W) -> Result<(), W::Error> {
218        write!(w, "{}", self.style.prefix())?;
219        w.write_str(self.string.as_ref())?;
220        write!(w, "{}", self.style.suffix())
221    }
222}
223
224
225// ---- writers for combined ANSI strings ----
226
227impl<'a> fmt::Display for ANSIStrings<'a> {
228    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
229        let f: &mut fmt::Write = f;
230        self.write_to_any(f)
231    }
232}
233
234impl<'a> ANSIByteStrings<'a> {
235    /// Write `ANSIByteStrings` to an `io::Write`.  This writes the minimal
236    /// escape sequences for the associated `Style`s around each set of
237    /// bytes.
238    pub fn write_to<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
239        let w: &mut io::Write = w;
240        self.write_to_any(w)
241    }
242}
243
244impl<'a, S: 'a + ToOwned + ?Sized + PartialEq> ANSIGenericStrings<'a, S>
245where <S as ToOwned>::Owned: fmt::Debug, &'a S: AsRef<[u8]> {
246    fn write_to_any<W: AnyWrite<wstr=S> + ?Sized>(&self, w: &mut W) -> Result<(), W::Error> {
247        use self::Difference::*;
248
249        let first = match self.0.first() {
250            None => return Ok(()),
251            Some(f) => f,
252        };
253
254        write!(w, "{}", first.style.prefix())?;
255        w.write_str(first.string.as_ref())?;
256
257        for window in self.0.windows(2) {
258            match Difference::between(&window[0].style, &window[1].style) {
259                ExtraStyles(style) => write!(w, "{}", style.prefix())?,
260                Reset              => write!(w, "{}{}", RESET, window[1].style.prefix())?,
261                NoDifference       => {/* Do nothing! */},
262            }
263
264            w.write_str(&window[1].string)?;
265        }
266
267        // Write the final reset string after all of the ANSIStrings have been
268        // written, *except* if the last one has no styles, because it would
269        // have already been written by this point.
270        if let Some(last) = self.0.last() {
271            if !last.style.is_plain() {
272                write!(w, "{}", RESET)?;
273            }
274        }
275
276        Ok(())
277    }
278}
279
280
281// ---- tests ----
282
283#[cfg(test)]
284mod tests {
285    pub use super::super::ANSIStrings;
286    pub use style::Style;
287    pub use style::Colour::*;
288
289    #[test]
290    fn no_control_codes_for_plain() {
291        let one = Style::default().paint("one");
292        let two = Style::default().paint("two");
293        let output = format!("{}", ANSIStrings( &[ one, two ] ));
294        assert_eq!(&*output, "onetwo");
295    }
296}
ansi_term/display.rs

ansi_term/
display.rs
