Add colored output

Colored output can be controlled on the command line with
`--use-color auto|always|never`. The default is `auto`, which enables
color if `imdl` detects that it is printing to a terminal.

Color can be disabled entirely by setting the `NO_COLOR` environment
variable.

type: added

.github/workflows/rust.yaml

@@ -29,7 +29,10 @@ jobs:
       run: cargo build --verbose
     - name: Test
       run: cargo test --verbose
-    - name: Lint
+    - name: Clippy
       run: cargo clippy
     - name: Format
       run: cargo fmt -- --check
+    - name: Lint
+      if: matrix.os != 'windows-latest'
+      run: "! grep --color -REn 'FIXME|TODO|XXX' src"

Cargo.lock

@@ -16,6 +16,14 @@ dependencies = [
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "ansi_term"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -63,6 +71,18 @@ name = "doc-comment"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "env_logger"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.1.14"
@@ -89,6 +109,14 @@ dependencies = [
  "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "humantime"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quick-error 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "idna"
 version = "0.2.0"
@@ -103,6 +131,9 @@ dependencies = [
 name = "imdl"
 version = "0.0.0"
 dependencies = [
+ "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
  "md5 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -128,6 +159,14 @@ name = "libc"
 version = "0.2.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "log"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "matches"
 version = "0.1.8"
@@ -185,6 +224,11 @@ dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "quote"
 version = "1.0.2"
@@ -274,7 +318,7 @@ name = "same-file"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -413,6 +457,14 @@ dependencies = [
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -482,7 +534,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "same-file 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -506,7 +558,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "winapi-util"
-version = "0.1.2"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -520,18 +572,22 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [metadata]
 "checksum aho-corasick 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)" = "58fb5e95d83b38284460a5fda7d6470aa0b8844d283a0b614b8535e880800d2d"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+"checksum ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
 "checksum atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum c2-chacha 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "214238caa1bf3a496ec3392968969cab8549f96ff30652c9e56885329315f6bb"
 "checksum cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 "checksum clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5067f5bb2d80ef5d68b4c87db81601f0b75bca627bc2ef76b141d7b846a3c6d9"
 "checksum doc-comment 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "923dea538cea0aa3025e8685b20d6ee21ef99c4f77e954a30febbaac5ec73a97"
+"checksum env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
 "checksum getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "7abc8dd8451921606d809ba32e95b6111925cd2906060d2dcc29c070220503eb"
 "checksum heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
 "checksum hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "eff2656d88f158ce120947499e971d743c05dbcbed62e5bd2f38f1698bbc3772"
+"checksum humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
 "checksum idna 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "02e2673c30ee86b5b96a9cb52ad15718aa1f966f5ab9ad54a8b95d5ca33120a9"
 "checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 "checksum libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)" = "d515b1f41455adea1313a4a2ac8a8a477634fbae63cc6100e3aebb207ce61558"
+"checksum log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
 "checksum matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
 "checksum md5 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "490cc448043f947bae3cbee9c203358d62dbee0db12107a74be5c30ccfd09771"
 "checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
@@ -540,6 +596,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum proc-macro-error 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "53c98547ceaea14eeb26fcadf51dc70d01a2479a7839170eae133721105e4428"
 "checksum proc-macro-error-attr 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c2bf5d493cf5d3e296beccfd61794e445e830dfc8070a9c248ad3ee071392c6c"
 "checksum proc-macro2 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "0319972dcae462681daf4da1adeeaa066e3ebd29c69be96c6abb1259d2ee2bcc"
+"checksum quick-error 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
 "checksum quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "053a8c8bcc71fcce321828dc897a98ab9760bef03a4fc36693c231e5b3216cfe"
 "checksum rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3ae1b169243eaf61759b8475a998f0a385e42042370f3a7dbaf35246eacc8412"
 "checksum rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "03a2a90da8c7523f554344f921aa97283eadf6ac484a6d2a7d0212fa7f8d6853"
@@ -567,6 +624,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum syn 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)" = "1e4ff033220a41d1a57d8125eab57bf5263783dfdcc18688b1dacc6ce9651ef8"
 "checksum syn-mid 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9fd3937748a7eccff61ba5b90af1a20dbf610858923a9192ea0ecb0cb77db1d0"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
+"checksum termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb6bfa289a4d7c5766392812c0a1f4c1ba45afa1ad47803c11e1f407d846d75f"
 "checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
 "checksum unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
@@ -580,5 +638,5 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)" = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
-"checksum winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7168bab6e1daee33b4557efd0e95d5ca70a03706d39fa5f3fe7a236f584b03c9"
+"checksum winapi-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4ccfbf554c6ad11084fb7517daca16cfdcaccbdadba4fc336f032a8b12c2ad80"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

Cargo.toml

@@ -12,18 +12,21 @@ repository  = "https://github.com/casey/intermodal"
 edition     = "2018"
 
 [dependencies]
-libc          = "0.2"
+ansi_term         = "0.12"
-md5           = "0.7"
+atty              = "0.2"
-regex         = "1"
+env_logger        = "0.7"
-serde_bencode = "0.2"
+libc              = "0.2"
-serde_bytes   = "0.11"
+md5               = "0.7"
-sha1          = "0.6"
+regex             = "1"
-snafu         = "0.6"
+serde_bencode     = "0.2"
-structopt     = "0.3"
+serde_bytes       = "0.11"
-tempfile      = "3"
+sha1              = "0.6"
-url           = "2"
+snafu             = "0.6"
-walkdir       = "2"
+static_assertions = "1"
-static_assertions = "1.1.0"
+structopt         = "0.3"
+tempfile          = "3"
+url               = "2"
+walkdir           = "2"
 
 [dependencies.serde]
 version = "1"

README.md

@@ -1 +1,36 @@
 # intermodal: a 40' shipping container for the Internet
+
+## Colored Output
+
+Intermodal features colored help, error, and informational output. Colored
+output is disabled if Intermodal detects that it is not printing to a TTY.
+
+To disable colored output, set the `NO_COLOR` environment variable to any
+valu or pass `--use-color never` on the command line.
+
+To force colored output, pass `--use-color always` on the command line.
+
+## Semantic Versioning and Unstable Features
+
+Intermodal follows [semantic versioning](https://semver.org/).
+
+In particular:
+
+- v0.0.X: Breaking changes may be introduced at any time.
+- v0.X.Y: Breaking changes may only be introduced with a minor version number
+  bump.
+- vX.Y.Z: Breaking changes may only be introduced with a major version number
+  bump
+
+To avoid premature stabilization and excessive version churn, unstable features
+are unavailable unless the `--unstable` / `-u` flag is passed. Unstable
+features may be changed or removed at any time.
+
+```
+$ imdl torrent stats --input tmp
+error: Feature `torrent stats subcommand` cannot be used without passing the `--unstable` flag
+$ imdl --unstable torrent stats tmp
+Torrents processed: 0
+Read failed:        0
+Decode failed:      0
+```

src/common.rs

@@ -3,7 +3,7 @@ pub(crate) use std::{
   borrow::Cow,
   cmp::{Ordering, Reverse},
   collections::{BTreeMap, HashMap},
-  convert::TryInto,
+  convert::{Infallible, TryInto},
   env,
   ffi::{OsStr, OsString},
   fmt::{self, Display, Formatter},
@@ -11,7 +11,8 @@ pub(crate) use std::{
   hash::Hash,
   io::{self, Read, Write},
   path::{Path, PathBuf},
-  process, str,
+  process,
+  str::{self, FromStr},
   time::{SystemTime, SystemTimeError},
   usize,
 };
@@ -28,7 +29,7 @@ pub(crate) use url::Url;
 pub(crate) use walkdir::WalkDir;
 
 // modules
-pub(crate) use crate::{bencode, consts, error, torrent};
+pub(crate) use crate::{bencode, consts, error, torrent, use_color};
 
 // traits
 pub(crate) use crate::{
@@ -38,7 +39,8 @@ pub(crate) use crate::{
 // structs and enums
 pub(crate) use crate::{
   env::Env, error::Error, file_info::FileInfo, hasher::Hasher, info::Info, metainfo::Metainfo,
-  mode::Mode, opt::Opt, subcommand::Subcommand, torrent::Torrent,
+  mode::Mode, opt::Opt, style::Style, subcommand::Subcommand, torrent::Torrent,
+  use_color::UseColor,
 };
 
 // test modules

src/env.rs

@@ -4,7 +4,8 @@ pub(crate) struct Env {
   args: Vec<String>,
   dir: Box<dyn AsRef<Path>>,
   pub(crate) err: Box<dyn Write>,
-  pub(crate) _out: Box<dyn Write>,
+  pub(crate) out: Box<dyn Write>,
+  err_style: Style,
 }
 
 impl Env {
@@ -14,14 +15,42 @@ impl Env {
       Err(error) => panic!("Failed to get current directory: {}", error),
     };
 
-    Self::new(dir, io::stdout(), io::stderr(), env::args())
+    let err_style = if env::var_os("NO_COLOR").is_some()
+      || env::var_os("TERM").as_deref() == Some(OsStr::new("dumb"))
+      || !atty::is(atty::Stream::Stderr)
+    {
+      Style::inactive()
+    } else {
+      Style::active()
+    };
+
+    Self::new(dir, io::stdout(), io::stderr(), err_style, env::args())
   }
 
   pub(crate) fn run(&mut self) -> Result<(), Error> {
-    Opt::from_iter_safe(&self.args)?.run(self)
+    #[cfg(windows)]
+    ansi_term::enable_ansi_support().ok();
+
+    #[cfg(not(test))]
+    env_logger::Builder::from_env(
+      env_logger::Env::new()
+        .filter("JUST_LOG")
+        .write_style("JUST_LOG_STYLE"),
+    )
+    .init();
+
+    let opt = Opt::from_iter_safe(&self.args)?;
+
+    match opt.use_color {
+      UseColor::Always => self.err_style = Style::active(),
+      UseColor::Auto => {}
+      UseColor::Never => self.err_style = Style::inactive(),
+    }
+
+    opt.run(self)
   }
 
-  pub(crate) fn new<D, O, E, S, I>(dir: D, out: O, err: E, args: I) -> Self
+  pub(crate) fn new<D, O, E, S, I>(dir: D, out: O, err: E, err_style: Style, args: I) -> Self
   where
     D: AsRef<Path> + 'static,
     O: Write + 'static,
@@ -33,21 +62,35 @@ impl Env {
       args: args.into_iter().map(Into::into).collect(),
       dir: Box::new(dir),
       err: Box::new(err),
-      _out: Box::new(out),
+      out: Box::new(out),
+      err_style,
     }
   }
 
   pub(crate) fn status(&mut self) -> Result<(), i32> {
     use structopt::clap::ErrorKind;
+
     if let Err(error) = self.run() {
       if let Error::Clap { source } = error {
-        write!(&mut self.err, "{}", source).ok();
+        if source.use_stderr() {
+          write!(&mut self.err, "{}", source).ok();
+        } else {
+          write!(&mut self.out, "{}", source).ok();
+        }
         match source.kind {
           ErrorKind::VersionDisplayed | ErrorKind::HelpDisplayed => Ok(()),
           _ => Err(EXIT_FAILURE),
         }
       } else {
-        write!(&mut self.err, "error: {}", error).ok();
+        writeln!(
+          &mut self.err,
+          "{}{}: {}{}",
+          self.err_style.error().paint("error"),
+          self.err_style.message().prefix(),
+          error,
+          self.err_style.message().suffix(),
+        )
+        .ok();
         Err(EXIT_FAILURE)
       }
     } else {

src/main.rs

@@ -10,6 +10,7 @@
   clippy::option_unwrap_used,
   clippy::result_expect_used,
   clippy::result_unwrap_used,
+  clippy::unreachable,
   clippy::wildcard_enum_match_arm
 )]
 
@@ -53,8 +54,10 @@ mod mode;
 mod opt;
 mod path_ext;
 mod reckoner;
+mod style;
 mod subcommand;
 mod torrent;
+mod use_color;
 
 fn main() {
   if let Err(code) = Env::main().status() {

src/opt.rs

@@ -1,18 +1,25 @@
 use crate::common::*;
 
-use structopt::clap::AppSettings;
+use structopt::clap::{AppSettings, ArgSettings};
 
 #[derive(StructOpt)]
 #[structopt(
   about(consts::ABOUT),
   version(consts::VERSION),
   author(consts::AUTHOR),
-  setting(AppSettings::ColoredHelp),
+  global_setting(AppSettings::ColoredHelp),
-  setting(AppSettings::ColorAuto)
+  global_setting(AppSettings::ColorAuto)
 )]
 pub(crate) struct Opt {
   #[structopt(long = "unstable", short = "u")]
   unstable: bool,
+  #[structopt(
+    long = "color",
+    default_value = use_color::AUTO,
+    set = ArgSettings::CaseInsensitive,
+    possible_values = use_color::VALUES,
+  )]
+  pub(crate) use_color: UseColor,
   #[structopt(subcommand)]
   subcommand: Subcommand,
 }

src/style.rs

@@ -0,0 +1,30 @@
+#[derive(Clone, Copy, Debug)]
+pub(crate) struct Style {
+  active: bool,
+}
+
+impl Style {
+  pub(crate) fn active() -> Self {
+    Self { active: true }
+  }
+
+  pub(crate) fn inactive() -> Self {
+    Self { active: false }
+  }
+
+  pub(crate) fn message(self) -> ansi_term::Style {
+    if self.active {
+      ansi_term::Style::new().bold()
+    } else {
+      ansi_term::Style::new()
+    }
+  }
+
+  pub(crate) fn error(self) -> ansi_term::Style {
+    if self.active {
+      ansi_term::Style::new().fg(ansi_term::Color::Red).bold()
+    } else {
+      ansi_term::Style::new()
+    }
+  }
+}

src/test_env.rs

@@ -15,6 +15,7 @@ impl TestEnv {
       tempfile::tempdir().unwrap(),
       out.clone(),
       err.clone(),
+      Style::inactive(),
       iter::once(String::from("imdl")).chain(iter.into_iter().map(|item| item.into())),
     );
 

src/torrent/stats.rs

@@ -45,17 +45,19 @@ impl Stats {
     let max = paths.iter().map(|(_, count)| *count).max().unwrap_or(0);
     let width = max.to_string().len();
 
-    errln!(env, "Keys:");
+    if !paths.is_empty() {
-    for (key, count) in &paths {
+      errln!(env, "Keys:");
-      if key.starts_with("info/files") {
+      for (key, count) in &paths {
-        continue;
+        if key.starts_with("info/files") {
-      }
+          continue;
-      errln!(env, "{:<width$} - {}", count, key, width = width);
+        }
-    }
-    for (key, count) in paths {
-      if key.starts_with("info/files") {
         errln!(env, "{:<width$} - {}", count, key, width = width);
       }
+      for (key, count) in paths {
+        if key.starts_with("info/files") {
+          errln!(env, "{:<width$} - {}", count, key, width = width);
+        }
+      }
     }
 
     if !extractor.values.is_empty() {

src/use_color.rs

@@ -0,0 +1,42 @@
+use crate::common::*;
+
+pub(crate) const AUTO: &str = "auto";
+pub(crate) const ALWAYS: &str = "always";
+pub(crate) const NEVER: &str = "never";
+
+pub(crate) const VALUES: &[&str] = &[AUTO, ALWAYS, NEVER];
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub(crate) enum UseColor {
+  Auto,
+  Always,
+  Never,
+}
+
+impl FromStr for UseColor {
+  type Err = Infallible;
+
+  fn from_str(text: &str) -> Result<Self, Self::Err> {
+    match text.to_lowercase().as_str() {
+      AUTO => Ok(Self::Auto),
+      ALWAYS => Ok(Self::Always),
+      NEVER => Ok(Self::Never),
+      _ => unreachable!(),
+    }
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn from_str() {
+    assert_eq!(UseColor::Auto, AUTO.parse().unwrap());
+    assert_eq!(UseColor::Always, ALWAYS.parse().unwrap());
+    assert_eq!(UseColor::Never, NEVER.parse().unwrap());
+    assert_eq!(UseColor::Auto, AUTO.to_uppercase().parse().unwrap());
+    assert_eq!(UseColor::Always, ALWAYS.to_uppercase().parse().unwrap());
+    assert_eq!(UseColor::Never, NEVER.to_uppercase().parse().unwrap());
+  }
+}