Completely re-work colored output and tty handling.

This commit completely guts all of the color handling code and replaces
most of it with two new crates: wincolor and termcolor. wincolor
provides a simple API to coloring using the Windows console and
termcolor provides a platform independent coloring API tuned for
multithreaded command line programs. This required a lot more
flexibility than what the `term` crate provided, so it was dropped.
We instead switch to writing ANSI escape sequences directly and ignore
the TERMINFO database.

In addition to fixing several bugs, this commit also permits end users
to customize colors to a certain extent. For example, this command will
set the match color to magenta and the line number background to yellow:

    rg --colors 'match:fg:magenta' --colors 'line:bg:yellow' foo

For tty handling, we've adopted a hack from `git` to do tty detection in
MSYS/mintty terminals. As a result, ripgrep should get both color
detection and piping correct on Windows regardless of which terminal you
use.

Finally, switch to line buffering. Performance doesn't seem to be
impacted and it's an otherwise more user friendly option.

Fixes #37, Fixes #51, Fixes #94, Fixes #117, Fixes #182, Fixes #231

src/args.rs

@@ -13,21 +13,14 @@ use grep::{Grep, GrepBuilder};
 use log;
 use num_cpus;
 use regex;
-use term::Terminal;
-#[cfg(not(windows))]
-use term;
-#[cfg(windows)]
-use term::WinConsole;
+use termcolor;
 
-use atty;
 use app;
+use atty;
 use ignore::overrides::{Override, OverrideBuilder};
 use ignore::types::{FileTypeDef, Types, TypesBuilder};
 use ignore;
-use out::{Out, ColoredTerminal};
-use printer::Printer;
-#[cfg(windows)]
-use terminal_win::WindowsBuffer;
+use printer::{ColorSpecs, Printer};
 use unescape::unescape;
 use worker::{Worker, WorkerBuilder};
 
@@ -40,6 +33,8 @@ pub struct Args {
     after_context: usize,
     before_context: usize,
     color: bool,
+    color_choice: termcolor::ColorChoice,
+    colors: ColorSpecs,
     column: bool,
     context_separator: Vec<u8>,
     count: bool,
@@ -132,8 +127,9 @@ impl Args {
 
     /// Create a new printer of individual search results that writes to the
     /// writer given.
-    pub fn printer<W: Terminal + Send>(&self, wtr: W) -> Printer<W> {
+    pub fn printer<W: termcolor::WriteColor>(&self, wtr: W) -> Printer<W> {
         let mut p = Printer::new(wtr)
+            .colors(self.colors.clone())
             .column(self.column)
             .context_separator(self.context_separator.clone())
             .eol(self.eol)
@@ -147,16 +143,6 @@ impl Args {
         p
     }
 
-    /// Create a new printer of search results for an entire file that writes
-    /// to the writer given.
-    pub fn out(&self) -> Out {
-        let mut out = Out::new(self.color);
-        if let Some(filesep) = self.file_separator() {
-            out = out.file_separator(filesep);
-        }
-        out
-    }
-
     /// Retrieve the configured file separator.
     pub fn file_separator(&self) -> Option<Vec<u8>> {
         if self.heading && !self.count && !self.files_with_matches && !self.files_without_matches {
@@ -173,30 +159,17 @@ impl Args {
         self.max_count == Some(0)
     }
 
-    /// Create a new buffer for use with searching.
-    #[cfg(not(windows))]
-    pub fn outbuf(&self) -> ColoredTerminal<term::TerminfoTerminal<Vec<u8>>> {
-        ColoredTerminal::new(vec![], self.color)
+    /// Create a new writer for single-threaded searching with color support.
+    pub fn stdout(&self) -> termcolor::Stdout {
+        termcolor::Stdout::new(self.color_choice)
     }
 
-    /// Create a new buffer for use with searching.
-    #[cfg(windows)]
-    pub fn outbuf(&self) -> ColoredTerminal<WindowsBuffer> {
-        ColoredTerminal::new_buffer(self.color)
-    }
-
-    /// Create a new buffer for use with searching.
-    #[cfg(not(windows))]
-    pub fn stdout(
-        &self,
-    ) -> ColoredTerminal<term::TerminfoTerminal<io::BufWriter<io::Stdout>>> {
-        ColoredTerminal::new(io::BufWriter::new(io::stdout()), self.color)
-    }
-
-    /// Create a new buffer for use with searching.
-    #[cfg(windows)]
-    pub fn stdout(&self) -> ColoredTerminal<WinConsole<io::Stdout>> {
-        ColoredTerminal::new_stdout(self.color)
+    /// Create a new buffer writer for multi-threaded searching with color
+    /// support.
+    pub fn buffer_writer(&self) -> termcolor::BufferWriter {
+        let mut wtr = termcolor::BufferWriter::stdout(self.color_choice);
+        wtr.separator(self.file_separator());
+        wtr
     }
 
     /// Return the paths that should be searched.
@@ -312,6 +285,8 @@ impl<'a> ArgMatches<'a> {
             after_context: after_context,
             before_context: before_context,
             color: self.color(),
+            color_choice: self.color_choice(),
+            colors: try!(self.color_specs()),
             column: self.column(),
             context_separator: self.context_separator(),
             count: self.is_present("count"),
@@ -617,6 +592,50 @@ impl<'a> ArgMatches<'a> {
         }
     }
 
+    /// Returns the user's color choice based on command line parameters and
+    /// environment.
+    fn color_choice(&self) -> termcolor::ColorChoice {
+        let preference = match self.0.value_of_lossy("color") {
+            None => "auto".to_string(),
+            Some(v) => v.into_owned(),
+        };
+        if preference == "always" {
+            termcolor::ColorChoice::Always
+        } else if preference == "ansi" {
+            termcolor::ColorChoice::AlwaysAnsi
+        } else if self.is_present("vimgrep") {
+            termcolor::ColorChoice::Never
+        } else if preference == "auto" {
+            if atty::on_stdout() || self.is_present("pretty") {
+                termcolor::ColorChoice::Auto
+            } else {
+                termcolor::ColorChoice::Never
+            }
+        } else {
+            termcolor::ColorChoice::Never
+        }
+    }
+
+    /// Returns the color specifications given by the user on the CLI.
+    ///
+    /// If the was a problem parsing any of the provided specs, then an error
+    /// is returned.
+    fn color_specs(&self) -> Result<ColorSpecs> {
+        // Start with a default set of color specs.
+        let mut specs = vec![
+            "path:fg:green".parse().unwrap(),
+            "path:style:bold".parse().unwrap(),
+            "line:fg:blue".parse().unwrap(),
+            "line:style:bold".parse().unwrap(),
+            "match:fg:red".parse().unwrap(),
+            "match:style:bold".parse().unwrap(),
+        ];
+        for spec_str in self.values_of_lossy_vec("colors") {
+            specs.push(try!(spec_str.parse()));
+        }
+        Ok(ColorSpecs::new(&specs))
+    }
+
     /// Returns the approximate number of threads that ripgrep should use.
     fn threads(&self) -> Result<usize> {
         let threads = try!(self.usize_of("threads")).unwrap_or(0);