/*!
This crate provides a cross platform abstraction for writing colored text to
a terminal. Colors are written using either ANSI escape sequences or by
communicating with a Windows console. Much of this API was motivated by use
inside command line applications, where colors or styles can be configured
by the end user and/or the environment.
This crate also provides platform independent support for writing colored text
to an in memory buffer. While this is easy to do with ANSI escape sequences
(because they are in the buffer themselves), it is trickier to do with the
Windows console API, which requires synchronous communication.
# Organization
The `WriteColor` trait extends the `io::Write` trait with methods for setting
colors or resetting them.
`StandardStream` and `StandardStreamLock` both satisfy `WriteColor` and are
analogous to `std::io::Stdout` and `std::io::StdoutLock`, or `std::io::Stderr`
and `std::io::StderrLock`.
`Buffer` is an in memory buffer that supports colored text. In a parallel
program, each thread might write to its own buffer. A buffer can be printed to
using a `BufferWriter`. The advantage of this design is that each thread can
work in parallel on a buffer without having to synchronize access to global
resources such as the Windows console. Moreover, this design also prevents
interleaving of buffer output.
`Ansi` and `NoColor` both satisfy `WriteColor` for arbitrary implementors of
`io::Write`. These types are useful when you know exactly what you need. An
analogous type for the Windows console is not provided since it cannot exist.
# Example: using `StandardStream`
The `StandardStream` type in this crate works similarly to `std::io::Stdout`,
except it is augmented with methods for coloring by the `WriteColor` trait.
For example, to write some green text:
```rust,no_run
# fn test() -> Result<(), Box<::std::error::Error>> {
use std::io::Write;
use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
let mut stdout = StandardStream::stdout(ColorChoice::Always);
try!(stdout.set_color(ColorSpec::new().set_fg(Some(Color::Green))));
try!(writeln!(&mut stdout, "green text!"));
# Ok(()) }
```
# Example: using `BufferWriter`
A `BufferWriter` can create buffers and write buffers to stdout or stderr. It
does *not* implement `io::Write` or `WriteColor` itself. Instead, `Buffer`
implements `io::Write` and `io::WriteColor`.
This example shows how to print some green text to stderr.
```rust,no_run
# fn test() -> Result<(), Box<::std::error::Error>> {
use std::io::Write;
use termcolor::{BufferWriter, Color, ColorChoice, ColorSpec, WriteColor};
let mut bufwtr = BufferWriter::stderr(ColorChoice::Always);
let mut buffer = bufwtr.buffer();
try!(buffer.set_color(ColorSpec::new().set_fg(Some(Color::Green))));
try!(writeln!(&mut buffer, "green text!"));
try!(bufwtr.print(&buffer));
# Ok(()) }
```
*/
#![deny(missing_docs)]
#[cfg(windows)]
extern crate wincolor;
use std::env;
use std::error;
use std::fmt;
use std::io::{self, Write};
use std::str::FromStr;
#[cfg(windows)]
use std::sync::{Mutex, MutexGuard};
use std::sync::atomic::{AtomicBool, Ordering};
/// This trait describes the behavior of writers that support colored output.
pub trait WriteColor: io::Write {
/// Returns true if and only if the underlying writer supports colors.
fn supports_color(&self) -> bool;
/// Set the color settings of the writer.
///
/// Subsequent writes to this writer will use these settings until either
/// `reset` is called or new color settings are set.
///
/// If there was a problem setting the color settings, then an error is
/// returned.
fn set_color(&mut self,