1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356
use core::fmt;
use core::sync::atomic::AtomicU8;
use core::sync::atomic::{AtomicPtr, Ordering};
/// A function that decides whether styling should be applied.
///
/// A styling `Condition` can be specified globally via
/// [`yansi::whenever()`](crate::whenever()) or locally to a specific style via
/// the [`whenever()`](crate::Style::whenever()) builder method. Any time a
/// [`Painted`](crate::Painted) value is formatted, both the local and global
/// conditions are checked, and only when both evaluate to `true` is styling
/// actually applied.
///
/// A `Condition` is nothing more than a function that returns a `bool`. The
/// function is called each and every time a `Painted` is formatted, and so it
/// is expected to be fast. All of the built-in conditions (except for their
/// "live" variants) cache their first evaluation as a result: the
/// [`Condition::cached()`] constructor can do the same for your conditions.
///
/// # Built-In Conditions
///
/// `yansi` comes with built-in conditions for common scenarios that can be
/// enabled via crate features:
///
/// | feature(s) | condition | implication |
/// |------------------------------|---------------------------------|------------------------|
/// | `detect-tty` | [TTY Detectors] | `std`, [`is-terminal`] |
/// | `detect-env` | [Environment Variable Checkers] | `std` |
/// | [`detect-tty`, `detect-env`] | All Above, [Combo Detectors] | `std`, [`is-terminal`] |
///
/// [`is-terminal`]: https://docs.rs/is-terminal
///
/// For example, to enable the TTY detectors, enable the `detect-tty` feature:
///
/// ```toml
/// yansi = { version = "...", features = ["detect-tty"] }
/// ```
///
/// To enable the TTY detectors, env-var checkers, and combo detectors, enable
/// `detect-tty` _and_ `detect-env`:
///
/// ```toml
/// yansi = { version = "...", features = ["detect-tty", "detect-env"] }
/// ```
///
/// ```rust
/// # #[cfg(all(feature = "detect-tty", feature = "detect-env"))] {
/// use yansi::Condition;
///
/// yansi::whenever(Condition::TTY_AND_COLOR);
/// # }
/// ```
///
/// [TTY detectors]: Condition#impl-Condition-1
/// [Environment Variable Checkers]: Condition#impl-Condition-2
/// [Combo Detectors]: Condition#impl-Condition-3
///
/// # Custom Conditions
///
/// Custom, arbitrary conditions can be creared via [`Condition::from()`] or
/// [`Condition::cached()`].
///
/// ```rust
/// # #[cfg(all(feature = "detect-tty", feature = "detect-env"))] {
/// use yansi::{Condition, Style, Color::*};
///
/// // Combine two conditions (`stderr` is a TTY, `CLICOLOR` is set) into one.
/// static STDERR_COLOR: Condition = Condition::from(||
/// Condition::stderr_is_tty() && Condition::clicolor()
/// );
///
/// static DEBUG: Style = Yellow.bold().on_primary().invert().whenever(STDERR_COLOR);
/// # }
/// ```
#[repr(transparent)]
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Condition(
/// The function that gets called to check the condition.
pub fn() -> bool
);
#[repr(transparent)]
pub struct AtomicCondition(AtomicPtr<()>);
#[allow(unused)]
#[repr(transparent)]
pub struct CachedBool(AtomicU8);
impl Condition {
/// A condition that evaluates to `true` if the OS supports coloring.
///
/// Uses [`Condition::os_support()`]. On Windows, this condition tries to
/// enable coloring support on the first call and caches the result for
/// subsequent calls. Outside of Windows, this always evaluates to `true`.
pub const DEFAULT: Condition = Condition(Condition::os_support);
/// A condition that always evaluates to `true`.
pub const ALWAYS: Condition = Condition(Condition::always);
/// A condition that always evaluated to `false`.
pub const NEVER: Condition = Condition(Condition::never);
/// Creates a dynamically checked condition from a function `f`.
///
/// The function `f` is called anytime the condition is checked, including
/// every time a style with the condition is used.
///
/// # Example
///
/// ```rust,no_run
/// use yansi::Condition;
///
/// fn some_function() -> bool {
/// /* checking arbitrary conditions */
/// todo!()
/// }
///
/// // Create a custom static condition from a function.
/// static MY_CONDITION: Condition = Condition::from(some_function);
///
/// // Create a condition on the stack from a function.
/// let my_condition = Condition::from(some_function);
///
/// // Create a static condition from a closure that becomes a `fn`.
/// static MY_CONDITION_2: Condition = Condition::from(|| false);
///
/// // Create a condition on the stack from a closure that becomes a `fn`.
/// let my_condition = Condition::from(|| some_function());
/// ```
pub const fn from(f: fn() -> bool) -> Self {
Condition(f)
}
/// Creates a condition that is [`ALWAYS`](Self::ALWAYS) when `value` is
/// `true` and [`NEVER`](Self::NEVER) otherwise.
///
/// # Example
///
/// ```rust,no_run
/// use yansi::Condition;
///
/// fn some_function() -> bool {
/// /* checking arbitrary conditions */
/// todo!()
/// }
///
/// // Cache the result of `some_function()` so it doesn't get called each
/// // time the condition needs to be checked.
/// let my_condition = Condition::cached(some_function());
/// ```
pub const fn cached(value: bool) -> Self {
match value {
true => Condition::ALWAYS,
false => Condition::NEVER,
}
}
/// The backing function for [`Condition::ALWAYS`]. Returns `true` always.
pub const fn always() -> bool { true }
/// The backing function for [`Condition::NEVER`]. Returns `false` always.
pub const fn never() -> bool { false }
/// The backing function for [`Condition::DEFAULT`].
///
/// Returns `true` if the current OS supports ANSI escape sequences for
/// coloring. Outside of Windows, this always returns `true`. On Windows,
/// the first call to this function attempts to enable support and returns
/// whether it was successful every time thereafter.
pub fn os_support() -> bool {
crate::windows::cache_enable()
}
}
impl Default for Condition {
fn default() -> Self {
Condition::DEFAULT
}
}
impl core::ops::Deref for Condition {
type Target = fn() -> bool;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl AtomicCondition {
pub const DEFAULT: AtomicCondition = AtomicCondition::from(Condition::DEFAULT);
pub const fn from(value: Condition) -> Self {
AtomicCondition(AtomicPtr::new(value.0 as *mut ()))
}
pub fn store(&self, cond: Condition) {
self.0.store(cond.0 as *mut (), Ordering::Release)
}
pub fn read(&self) -> bool {
let condition = unsafe {
Condition(core::mem::transmute(self.0.load(Ordering::Acquire)))
};
condition()
}
}
#[allow(unused)]
impl CachedBool {
const TRUE: u8 = 1;
const UNINIT: u8 = 2;
const INITING: u8 = 3;
pub const fn new() -> Self {
CachedBool(AtomicU8::new(Self::UNINIT))
}
pub fn get_or_init(&self, f: impl FnOnce() -> bool) -> bool {
use core::sync::atomic::Ordering::*;
match self.0.compare_exchange(Self::UNINIT, Self::INITING, AcqRel, Relaxed) {
Ok(_) => {
let new_value = f();
self.0.store(new_value as u8 /* false = 0, true = 1 */, Release);
new_value
}
Err(Self::INITING) => {
let mut value;
while { value = self.0.load(Acquire); value } == Self::INITING {
#[cfg(feature = "std")]
std::thread::yield_now();
}
value == Self::TRUE
},
Err(value) => value == Self::TRUE,
}
}
}
impl fmt::Debug for Condition {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if *self == Condition::DEFAULT {
f.write_str("Condition::DEFAULT")
} else if *self == Condition::ALWAYS {
f.write_str("Condition::ALWAYS")
} else if *self == Condition::NEVER {
f.write_str("Condition::NEVER")
} else {
f.debug_tuple("Condition").field(&self.0).finish()
}
}
}
macro_rules! conditions {
($feat:meta $($f:expr, $CACHED:ident: $cached:ident, $LIVE:ident: $live:ident),* $(,)?) => (
#[cfg($feat)]
#[cfg_attr(feature = "_nightly", doc(cfg($feat)))]
/// Feature dependent conditions.
///
/// Available when compiled with
#[doc = concat!('`', stringify!($feat), "`.")]
impl Condition {
$(
/// Evaluates to `true` if
#[doc = concat!('`', stringify!($f), "`.")]
///
/// The result of the first check is cached for subsequent
/// checks. Internally uses
#[doc = concat!("[`", stringify!($cached), "`](Condition::", stringify!($cached), ").")]
pub const $CACHED: Condition = Condition(Condition::$cached);
)*
$(
/// Evaluates to `true` if
#[doc = concat!('`', stringify!($f), "`.")]
///
/// A call is dispatched each time the condition is checked.
/// This is expensive, so prefer to use
#[doc = concat!("[`", stringify!($CACHED), "`](Condition::", stringify!($CACHED), ")")]
/// instead.
///
/// Internally uses
#[doc = concat!("[`", stringify!($live), "`](Condition::", stringify!($live), ").")]
pub const $LIVE: Condition = Condition(Condition::$live);
)*
$(
/// Returns `true` if
#[doc = concat!('`', stringify!($f), "`.")]
///
/// The result of the first check is cached for subsequent
/// checks. This is the backing function for
#[doc = concat!("[`", stringify!($CACHED), "`](Condition::", stringify!($CACHED), ").")]
pub fn $cached() -> bool {
static IS_TTY: CachedBool = CachedBool::new();
IS_TTY.get_or_init(Condition::$live)
}
)*
$(
/// Returns `true` if
#[doc = concat!('`', stringify!($f), "`.")]
///
/// This is the backing function for
#[doc = concat!("[`", stringify!($LIVE), "`](Condition::", stringify!($LIVE), ").")]
pub fn $live() -> bool {
$f
}
)*
}
)
}
#[cfg(feature = "detect-tty")]
use is_terminal::is_terminal as is_tty;
conditions! { feature = "detect-tty"
is_tty(&std::io::stdout()),
STDOUT_IS_TTY: stdout_is_tty,
STDOUT_IS_TTY_LIVE: stdout_is_tty_live,
is_tty(&std::io::stderr()),
STDERR_IS_TTY: stderr_is_tty,
STDERR_IS_TTY_LIVE: stderr_is_tty_live,
is_tty(&std::io::stdin()),
STDIN_IS_TTY: stdin_is_tty,
STDIN_IS_TTY_LIVE: stdin_is_tty_live,
is_tty(&std::io::stdout()) && is_tty(&std::io::stderr()),
STDOUTERR_ARE_TTY: stdouterr_are_tty,
STDOUTERR_ARE_TTY_LIVE: stdouterr_are_tty_live,
}
#[cfg(feature = "detect-env")]
pub fn env_set_or(name: &str, default: bool) -> bool {
std::env::var_os(name).map_or(default, |v| v != "0")
}
conditions! { feature = "detect-env"
env_set_or("CLICOLOR_FORCE", false) || env_set_or("CLICOLOR", true),
CLICOLOR: clicolor,
CLICOLOR_LIVE: clicolor_live,
!env_set_or("NO_COLOR", false),
YES_COLOR: no_color,
YES_COLOR_LIVE: no_color_live,
}
conditions! { all(feature = "detect-env", feature = "detect-tty")
Condition::stdouterr_are_tty() && Condition::clicolor() && Condition::no_color(),
TTY_AND_COLOR: tty_and_color,
TTY_AND_COLOR_LIVE: tty_and_color_live,
}