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Diffstat (limited to 'vendor/tracing-subscriber/src/filter/layer_filters/combinator.rs')
| -rw-r--r-- | vendor/tracing-subscriber/src/filter/layer_filters/combinator.rs | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/vendor/tracing-subscriber/src/filter/layer_filters/combinator.rs b/vendor/tracing-subscriber/src/filter/layer_filters/combinator.rs new file mode 100644 index 000000000..3934a1326 --- /dev/null +++ b/vendor/tracing-subscriber/src/filter/layer_filters/combinator.rs @@ -0,0 +1,542 @@ +//! Filter combinators +use crate::layer::{Context, Filter}; +use std::{cmp, fmt, marker::PhantomData}; +use tracing_core::{ + span::{Attributes, Id, Record}, + subscriber::Interest, + LevelFilter, Metadata, +}; + +/// Combines two [`Filter`]s so that spans and events are enabled if and only if +/// *both* filters return `true`. +/// +/// This type is typically returned by the [`FilterExt::and`] method. See that +/// method's documentation for details. +/// +/// [`Filter`]: crate::layer::Filter +/// [`FilterExt::and`]: crate::filter::FilterExt::and +pub struct And<A, B, S> { + a: A, + b: B, + _s: PhantomData<fn(S)>, +} + +/// Combines two [`Filter`]s so that spans and events are enabled if *either* filter +/// returns `true`. +/// +/// This type is typically returned by the [`FilterExt::or`] method. See that +/// method's documentation for details. +/// +/// [`Filter`]: crate::layer::Filter +/// [`FilterExt::or`]: crate::filter::FilterExt::or +pub struct Or<A, B, S> { + a: A, + b: B, + _s: PhantomData<fn(S)>, +} + +/// Inverts the result of a [`Filter`]. +/// +/// If the wrapped filter would enable a span or event, it will be disabled. If +/// it would disable a span or event, that span or event will be enabled. +/// +/// This type is typically returned by the [`FilterExt::not`] method. See that +/// method's documentation for details. +/// +/// [`Filter`]: crate::layer::Filter +/// [`FilterExt::not`]: crate::filter::FilterExt::not +pub struct Not<A, S> { + a: A, + _s: PhantomData<fn(S)>, +} + +// === impl And === + +impl<A, B, S> And<A, B, S> +where + A: Filter<S>, + B: Filter<S>, +{ + /// Combines two [`Filter`]s so that spans and events are enabled if and only if + /// *both* filters return `true`. + /// + /// # Examples + /// + /// Enabling spans or events if they have both a particular target *and* are + /// above a certain level: + /// + /// ```ignore + /// use tracing_subscriber::{ + /// filter::{filter_fn, LevelFilter, combinator::And}, + /// prelude::*, + /// }; + /// + /// // Enables spans and events with targets starting with `interesting_target`: + /// let target_filter = filter_fn(|meta| { + /// meta.target().starts_with("interesting_target") + /// }); + /// + /// // Enables spans and events with levels `INFO` and below: + /// let level_filter = LevelFilter::INFO; + /// + /// // Combine the two filters together so that a span or event is only enabled + /// // if *both* filters would enable it: + /// let filter = And::new(level_filter, target_filter); + /// + /// tracing_subscriber::registry() + /// .with(tracing_subscriber::fmt::layer().with_filter(filter)) + /// .init(); + /// + /// // This event will *not* be enabled: + /// tracing::info!("an event with an uninteresting target"); + /// + /// // This event *will* be enabled: + /// tracing::info!(target: "interesting_target", "a very interesting event"); + /// + /// // This event will *not* be enabled: + /// tracing::debug!(target: "interesting_target", "interesting debug event..."); + /// ``` + /// + /// [`Filter`]: crate::layer::Filter + pub(crate) fn new(a: A, b: B) -> Self { + Self { + a, + b, + _s: PhantomData, + } + } +} + +impl<A, B, S> Filter<S> for And<A, B, S> +where + A: Filter<S>, + B: Filter<S>, +{ + #[inline] + fn enabled(&self, meta: &Metadata<'_>, cx: &Context<'_, S>) -> bool { + self.a.enabled(meta, cx) && self.b.enabled(meta, cx) + } + + fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest { + let a = self.a.callsite_enabled(meta); + if a.is_never() { + return a; + } + + let b = self.b.callsite_enabled(meta); + + if !b.is_always() { + return b; + } + + a + } + + fn max_level_hint(&self) -> Option<LevelFilter> { + // If either hint is `None`, return `None`. Otherwise, return the most restrictive. + cmp::min(self.a.max_level_hint(), self.b.max_level_hint()) + } + + #[inline] + fn event_enabled(&self, event: &tracing_core::Event<'_>, cx: &Context<'_, S>) -> bool { + self.a.event_enabled(event, cx) && self.b.event_enabled(event, cx) + } + + #[inline] + fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) { + self.a.on_new_span(attrs, id, ctx.clone()); + self.b.on_new_span(attrs, id, ctx) + } + + #[inline] + fn on_record(&self, id: &Id, values: &Record<'_>, ctx: Context<'_, S>) { + self.a.on_record(id, values, ctx.clone()); + self.b.on_record(id, values, ctx); + } + + #[inline] + fn on_enter(&self, id: &Id, ctx: Context<'_, S>) { + self.a.on_enter(id, ctx.clone()); + self.b.on_enter(id, ctx); + } + + #[inline] + fn on_exit(&self, id: &Id, ctx: Context<'_, S>) { + self.a.on_exit(id, ctx.clone()); + self.b.on_exit(id, ctx); + } + + #[inline] + fn on_close(&self, id: Id, ctx: Context<'_, S>) { + self.a.on_close(id.clone(), ctx.clone()); + self.b.on_close(id, ctx); + } +} + +impl<A, B, S> Clone for And<A, B, S> +where + A: Clone, + B: Clone, +{ + fn clone(&self) -> Self { + Self { + a: self.a.clone(), + b: self.b.clone(), + _s: PhantomData, + } + } +} + +impl<A, B, S> fmt::Debug for And<A, B, S> +where + A: fmt::Debug, + B: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("And") + .field("a", &self.a) + .field("b", &self.b) + .finish() + } +} + +// === impl Or === + +impl<A, B, S> Or<A, B, S> +where + A: Filter<S>, + B: Filter<S>, +{ + /// Combines two [`Filter`]s so that spans and events are enabled if *either* filter + /// returns `true`. + /// + /// # Examples + /// + /// Enabling spans and events at the `INFO` level and above, and all spans + /// and events with a particular target: + /// + /// ```ignore + /// use tracing_subscriber::{ + /// filter::{filter_fn, LevelFilter, combinator::Or}, + /// prelude::*, + /// }; + /// + /// // Enables spans and events with targets starting with `interesting_target`: + /// let target_filter = filter_fn(|meta| { + /// meta.target().starts_with("interesting_target") + /// }); + /// + /// // Enables spans and events with levels `INFO` and below: + /// let level_filter = LevelFilter::INFO; + /// + /// // Combine the two filters together so that a span or event is enabled + /// // if it is at INFO or lower, or if it has a target starting with + /// // `interesting_target`. + /// let filter = Or::new(level_filter, target_filter); + /// + /// tracing_subscriber::registry() + /// .with(tracing_subscriber::fmt::layer().with_filter(filter)) + /// .init(); + /// + /// // This event will *not* be enabled: + /// tracing::debug!("an uninteresting event"); + /// + /// // This event *will* be enabled: + /// tracing::info!("an uninteresting INFO event"); + /// + /// // This event *will* be enabled: + /// tracing::info!(target: "interesting_target", "a very interesting event"); + /// + /// // This event *will* be enabled: + /// tracing::debug!(target: "interesting_target", "interesting debug event..."); + /// ``` + /// + /// Enabling a higher level for a particular target by using `Or` in + /// conjunction with the [`And`] combinator: + /// + /// ```ignore + /// use tracing_subscriber::{ + /// filter::{filter_fn, LevelFilter, combinator}, + /// prelude::*, + /// }; + /// + /// // This filter will enable spans and events with targets beginning with + /// // `my_crate`: + /// let my_crate = filter_fn(|meta| { + /// meta.target().starts_with("my_crate") + /// }); + /// + /// // Combine the `my_crate` filter with a `LevelFilter` to produce a filter + /// // that will enable the `INFO` level and lower for spans and events with + /// // `my_crate` targets: + /// let filter = combinator::And::new(my_crate, LevelFilter::INFO); + /// + /// // If a span or event *doesn't* have a target beginning with + /// // `my_crate`, enable it if it has the `WARN` level or lower: + /// // let filter = combinator::Or::new(filter, LevelFilter::WARN); + /// + /// tracing_subscriber::registry() + /// .with(tracing_subscriber::fmt::layer().with_filter(filter)) + /// .init(); + /// ``` + /// + /// [`Filter`]: crate::layer::Filter + pub(crate) fn new(a: A, b: B) -> Self { + Self { + a, + b, + _s: PhantomData, + } + } +} + +impl<A, B, S> Filter<S> for Or<A, B, S> +where + A: Filter<S>, + B: Filter<S>, +{ + #[inline] + fn enabled(&self, meta: &Metadata<'_>, cx: &Context<'_, S>) -> bool { + self.a.enabled(meta, cx) || self.b.enabled(meta, cx) + } + + fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest { + let a = self.a.callsite_enabled(meta); + let b = self.b.callsite_enabled(meta); + + // If either filter will always enable the span or event, return `always`. + if a.is_always() || b.is_always() { + return Interest::always(); + } + + // Okay, if either filter will sometimes enable the span or event, + // return `sometimes`. + if a.is_sometimes() || b.is_sometimes() { + return Interest::sometimes(); + } + + debug_assert!( + a.is_never() && b.is_never(), + "if neither filter was `always` or `sometimes`, both must be `never` (a={:?}; b={:?})", + a, + b, + ); + Interest::never() + } + + fn max_level_hint(&self) -> Option<LevelFilter> { + // If either hint is `None`, return `None`. Otherwise, return the less restrictive. + Some(cmp::max(self.a.max_level_hint()?, self.b.max_level_hint()?)) + } + + #[inline] + fn event_enabled(&self, event: &tracing_core::Event<'_>, cx: &Context<'_, S>) -> bool { + self.a.event_enabled(event, cx) || self.b.event_enabled(event, cx) + } + + #[inline] + fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) { + self.a.on_new_span(attrs, id, ctx.clone()); + self.b.on_new_span(attrs, id, ctx) + } + + #[inline] + fn on_record(&self, id: &Id, values: &Record<'_>, ctx: Context<'_, S>) { + self.a.on_record(id, values, ctx.clone()); + self.b.on_record(id, values, ctx); + } + + #[inline] + fn on_enter(&self, id: &Id, ctx: Context<'_, S>) { + self.a.on_enter(id, ctx.clone()); + self.b.on_enter(id, ctx); + } + + #[inline] + fn on_exit(&self, id: &Id, ctx: Context<'_, S>) { + self.a.on_exit(id, ctx.clone()); + self.b.on_exit(id, ctx); + } + + #[inline] + fn on_close(&self, id: Id, ctx: Context<'_, S>) { + self.a.on_close(id.clone(), ctx.clone()); + self.b.on_close(id, ctx); + } +} + +impl<A, B, S> Clone for Or<A, B, S> +where + A: Clone, + B: Clone, +{ + fn clone(&self) -> Self { + Self { + a: self.a.clone(), + b: self.b.clone(), + _s: PhantomData, + } + } +} + +impl<A, B, S> fmt::Debug for Or<A, B, S> +where + A: fmt::Debug, + B: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Or") + .field("a", &self.a) + .field("b", &self.b) + .finish() + } +} + +// === impl Not === + +impl<A, S> Not<A, S> +where + A: Filter<S>, +{ + /// Inverts the result of a [`Filter`]. + /// + /// If the wrapped filter would enable a span or event, it will be disabled. If + /// it would disable a span or event, that span or event will be enabled. + /// + /// This inverts the values returned by the [`enabled`] and [`callsite_enabled`] + /// methods on the wrapped filter; it does *not* invert [`event_enabled`], as + /// filters which do not implement filtering on event field values will return + /// the default `true` even for events that their [`enabled`] method disables. + /// + /// Consider a normal filter defined as: + /// + /// ```ignore (pseudo-code) + /// // for spans + /// match callsite_enabled() { + /// ALWAYS => on_span(), + /// SOMETIMES => if enabled() { on_span() }, + /// NEVER => (), + /// } + /// // for events + /// match callsite_enabled() { + /// ALWAYS => on_event(), + /// SOMETIMES => if enabled() && event_enabled() { on_event() }, + /// NEVER => (), + /// } + /// ``` + /// + /// and an inverted filter defined as: + /// + /// ```ignore (pseudo-code) + /// // for spans + /// match callsite_enabled() { + /// ALWAYS => (), + /// SOMETIMES => if !enabled() { on_span() }, + /// NEVER => on_span(), + /// } + /// // for events + /// match callsite_enabled() { + /// ALWAYS => (), + /// SOMETIMES => if !enabled() { on_event() }, + /// NEVER => on_event(), + /// } + /// ``` + /// + /// A proper inversion would do `!(enabled() && event_enabled())` (or + /// `!enabled() || !event_enabled()`), but because of the implicit `&&` + /// relation between `enabled` and `event_enabled`, it is difficult to + /// short circuit and not call the wrapped `event_enabled`. + /// + /// A combinator which remembers the result of `enabled` in order to call + /// `event_enabled` only when `enabled() == true` is possible, but requires + /// additional thread-local mutable state to support a very niche use case. + // + // Also, it'd mean the wrapped layer's `enabled()` always gets called and + // globally applied to events where it doesn't today, since we can't know + // what `event_enabled` will say until we have the event to call it with. + /// + /// [`Filter`]: crate::layer::Filter + /// [`enabled`]: crate::layer::Filter::enabled + /// [`event_enabled`]: crate::layer::Filter::event_enabled + /// [`callsite_enabled`]: crate::layer::Filter::callsite_enabled + pub(crate) fn new(a: A) -> Self { + Self { a, _s: PhantomData } + } +} + +impl<A, S> Filter<S> for Not<A, S> +where + A: Filter<S>, +{ + #[inline] + fn enabled(&self, meta: &Metadata<'_>, cx: &Context<'_, S>) -> bool { + !self.a.enabled(meta, cx) + } + + fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest { + match self.a.callsite_enabled(meta) { + i if i.is_always() => Interest::never(), + i if i.is_never() => Interest::always(), + _ => Interest::sometimes(), + } + } + + fn max_level_hint(&self) -> Option<LevelFilter> { + // TODO(eliza): figure this out??? + None + } + + #[inline] + fn event_enabled(&self, event: &tracing_core::Event<'_>, cx: &Context<'_, S>) -> bool { + // Never disable based on event_enabled; we "disabled" it in `enabled`, + // so the `not` has already been applied and filtered this not out. + let _ = (event, cx); + true + } + + #[inline] + fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) { + self.a.on_new_span(attrs, id, ctx); + } + + #[inline] + fn on_record(&self, id: &Id, values: &Record<'_>, ctx: Context<'_, S>) { + self.a.on_record(id, values, ctx.clone()); + } + + #[inline] + fn on_enter(&self, id: &Id, ctx: Context<'_, S>) { + self.a.on_enter(id, ctx); + } + + #[inline] + fn on_exit(&self, id: &Id, ctx: Context<'_, S>) { + self.a.on_exit(id, ctx); + } + + #[inline] + fn on_close(&self, id: Id, ctx: Context<'_, S>) { + self.a.on_close(id, ctx); + } +} + +impl<A, S> Clone for Not<A, S> +where + A: Clone, +{ + fn clone(&self) -> Self { + Self { + a: self.a.clone(), + _s: PhantomData, + } + } +} + +impl<A, S> fmt::Debug for Not<A, S> +where + A: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("Not").field(&self.a).finish() + } +} |