diff options
Diffstat (limited to 'vendor/tracing-subscriber/src/filter/directive.rs')
| -rw-r--r-- | vendor/tracing-subscriber/src/filter/directive.rs | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/vendor/tracing-subscriber/src/filter/directive.rs b/vendor/tracing-subscriber/src/filter/directive.rs new file mode 100644 index 000000000..2ae3f0f24 --- /dev/null +++ b/vendor/tracing-subscriber/src/filter/directive.rs @@ -0,0 +1,456 @@ +use crate::filter::level::{self, LevelFilter}; +#[cfg(not(feature = "smallvec"))] +use alloc::vec; +#[cfg(not(feature = "std"))] +use alloc::{string::String, vec::Vec}; + +use core::{cmp::Ordering, fmt, iter::FromIterator, slice, str::FromStr}; +use tracing_core::{Level, Metadata}; +/// Indicates that a string could not be parsed as a filtering directive. +#[derive(Debug)] +pub struct ParseError { + kind: ParseErrorKind, +} + +/// A directive which will statically enable or disable a given callsite. +/// +/// Unlike a dynamic directive, this can be cached by the callsite. +#[derive(Debug, PartialEq, Eq, Clone)] +pub(crate) struct StaticDirective { + pub(in crate::filter) target: Option<String>, + pub(in crate::filter) field_names: Vec<String>, + pub(in crate::filter) level: LevelFilter, +} + +#[cfg(feature = "smallvec")] +pub(crate) type FilterVec<T> = smallvec::SmallVec<[T; 8]>; +#[cfg(not(feature = "smallvec"))] +pub(crate) type FilterVec<T> = Vec<T>; + +#[derive(Debug, PartialEq, Clone)] +pub(in crate::filter) struct DirectiveSet<T> { + directives: FilterVec<T>, + pub(in crate::filter) max_level: LevelFilter, +} + +pub(in crate::filter) trait Match { + fn cares_about(&self, meta: &Metadata<'_>) -> bool; + fn level(&self) -> &LevelFilter; +} + +#[derive(Debug)] +enum ParseErrorKind { + #[cfg(feature = "std")] + Field(Box<dyn std::error::Error + Send + Sync>), + Level(level::ParseError), + Other(Option<&'static str>), +} + +// === impl DirectiveSet === + +impl<T> DirectiveSet<T> { + #[cfg(feature = "env-filter")] + pub(crate) fn is_empty(&self) -> bool { + self.directives.is_empty() + } + + pub(crate) fn iter(&self) -> slice::Iter<'_, T> { + self.directives.iter() + } +} + +impl<T: Ord> Default for DirectiveSet<T> { + fn default() -> Self { + Self { + directives: FilterVec::new(), + max_level: LevelFilter::OFF, + } + } +} + +impl<T: Match + Ord> DirectiveSet<T> { + pub(crate) fn directives(&self) -> impl Iterator<Item = &T> { + self.directives.iter() + } + + pub(crate) fn directives_for<'a>( + &'a self, + metadata: &'a Metadata<'a>, + ) -> impl Iterator<Item = &'a T> + 'a { + self.directives().filter(move |d| d.cares_about(metadata)) + } + + pub(crate) fn add(&mut self, directive: T) { + // does this directive enable a more verbose level than the current + // max? if so, update the max level. + let level = *directive.level(); + if level > self.max_level { + self.max_level = level; + } + // insert the directive into the vec of directives, ordered by + // specificity (length of target + number of field filters). this + // ensures that, when finding a directive to match a span or event, we + // search the directive set in most specific first order. + match self.directives.binary_search(&directive) { + Ok(i) => self.directives[i] = directive, + Err(i) => self.directives.insert(i, directive), + } + } + + #[cfg(test)] + pub(in crate::filter) fn into_vec(self) -> FilterVec<T> { + self.directives + } +} + +impl<T: Match + Ord> FromIterator<T> for DirectiveSet<T> { + fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self { + let mut this = Self::default(); + this.extend(iter); + this + } +} + +impl<T: Match + Ord> Extend<T> for DirectiveSet<T> { + fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { + for directive in iter.into_iter() { + self.add(directive); + } + } +} + +impl<T> IntoIterator for DirectiveSet<T> { + type Item = T; + + #[cfg(feature = "smallvec")] + type IntoIter = smallvec::IntoIter<[T; 8]>; + #[cfg(not(feature = "smallvec"))] + type IntoIter = vec::IntoIter<T>; + + fn into_iter(self) -> Self::IntoIter { + self.directives.into_iter() + } +} + +// === impl Statics === + +impl DirectiveSet<StaticDirective> { + pub(crate) fn enabled(&self, meta: &Metadata<'_>) -> bool { + let level = meta.level(); + match self.directives_for(meta).next() { + Some(d) => d.level >= *level, + None => false, + } + } + + /// Same as `enabled` above, but skips `Directive`'s with fields. + pub(crate) fn target_enabled(&self, target: &str, level: &Level) -> bool { + match self.directives_for_target(target).next() { + Some(d) => d.level >= *level, + None => false, + } + } + + pub(crate) fn directives_for_target<'a>( + &'a self, + target: &'a str, + ) -> impl Iterator<Item = &'a StaticDirective> + 'a { + self.directives() + .filter(move |d| d.cares_about_target(target)) + } +} + +// === impl StaticDirective === + +impl StaticDirective { + pub(in crate::filter) fn new( + target: Option<String>, + field_names: Vec<String>, + level: LevelFilter, + ) -> Self { + Self { + target, + field_names, + level, + } + } + + pub(in crate::filter) fn cares_about_target(&self, to_check: &str) -> bool { + // Does this directive have a target filter, and does it match the + // metadata's target? + if let Some(ref target) = self.target { + if !to_check.starts_with(&target[..]) { + return false; + } + } + + if !self.field_names.is_empty() { + return false; + } + + true + } +} + +impl Ord for StaticDirective { + fn cmp(&self, other: &StaticDirective) -> Ordering { + // We attempt to order directives by how "specific" they are. This + // ensures that we try the most specific directives first when + // attempting to match a piece of metadata. + + // First, we compare based on whether a target is specified, and the + // lengths of those targets if both have targets. + let ordering = self + .target + .as_ref() + .map(String::len) + .cmp(&other.target.as_ref().map(String::len)) + // Then we compare how many field names are matched by each directive. + .then_with(|| self.field_names.len().cmp(&other.field_names.len())) + // Finally, we fall back to lexicographical ordering if the directives are + // equally specific. Although this is no longer semantically important, + // we need to define a total ordering to determine the directive's place + // in the BTreeMap. + .then_with(|| { + self.target + .cmp(&other.target) + .then_with(|| self.field_names[..].cmp(&other.field_names[..])) + }) + .reverse(); + + #[cfg(debug_assertions)] + { + if ordering == Ordering::Equal { + debug_assert_eq!( + self.target, other.target, + "invariant violated: Ordering::Equal must imply a.target == b.target" + ); + debug_assert_eq!( + self.field_names, other.field_names, + "invariant violated: Ordering::Equal must imply a.field_names == b.field_names" + ); + } + } + + ordering + } +} + +impl PartialOrd for StaticDirective { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + Some(self.cmp(other)) + } +} + +impl Match for StaticDirective { + fn cares_about(&self, meta: &Metadata<'_>) -> bool { + // Does this directive have a target filter, and does it match the + // metadata's target? + if let Some(ref target) = self.target { + if !meta.target().starts_with(&target[..]) { + return false; + } + } + + if meta.is_event() && !self.field_names.is_empty() { + let fields = meta.fields(); + for name in &self.field_names { + if fields.field(name).is_none() { + return false; + } + } + } + + true + } + + fn level(&self) -> &LevelFilter { + &self.level + } +} + +impl Default for StaticDirective { + fn default() -> Self { + StaticDirective { + target: None, + field_names: Vec::new(), + level: LevelFilter::ERROR, + } + } +} + +impl fmt::Display for StaticDirective { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let mut wrote_any = false; + if let Some(ref target) = self.target { + fmt::Display::fmt(target, f)?; + wrote_any = true; + } + + if !self.field_names.is_empty() { + f.write_str("[")?; + + let mut fields = self.field_names.iter(); + if let Some(field) = fields.next() { + write!(f, "{{{}", field)?; + for field in fields { + write!(f, ",{}", field)?; + } + f.write_str("}")?; + } + + f.write_str("]")?; + wrote_any = true; + } + + if wrote_any { + f.write_str("=")?; + } + + fmt::Display::fmt(&self.level, f) + } +} + +impl FromStr for StaticDirective { + type Err = ParseError; + + fn from_str(s: &str) -> Result<Self, Self::Err> { + // This method parses a filtering directive in one of the following + // forms: + // + // * `foo=trace` (TARGET=LEVEL) + // * `foo[{bar,baz}]=info` (TARGET[{FIELD,+}]=LEVEL) + // * `trace` (bare LEVEL) + // * `foo` (bare TARGET) + let mut split = s.split('='); + let part0 = split + .next() + .ok_or_else(|| ParseError::msg("string must not be empty"))?; + + // Directive includes an `=`: + // * `foo=trace` + // * `foo[{bar}]=trace` + // * `foo[{bar,baz}]=trace` + if let Some(part1) = split.next() { + if split.next().is_some() { + return Err(ParseError::msg( + "too many '=' in filter directive, expected 0 or 1", + )); + } + + let mut split = part0.split("[{"); + let target = split.next().map(String::from); + let mut field_names = Vec::new(); + // Directive includes fields: + // * `foo[{bar}]=trace` + // * `foo[{bar,baz}]=trace` + if let Some(maybe_fields) = split.next() { + if split.next().is_some() { + return Err(ParseError::msg( + "too many '[{' in filter directive, expected 0 or 1", + )); + } + + if !maybe_fields.ends_with("}]") { + return Err(ParseError::msg("expected fields list to end with '}]'")); + } + + let fields = maybe_fields + .trim_end_matches("}]") + .split(',') + .filter_map(|s| { + if s.is_empty() { + None + } else { + Some(String::from(s)) + } + }); + field_names.extend(fields); + }; + let level = part1.parse()?; + return Ok(Self { + level, + field_names, + target, + }); + } + + // Okay, the part after the `=` was empty, the directive is either a + // bare level or a bare target. + // * `foo` + // * `info` + Ok(match part0.parse::<LevelFilter>() { + Ok(level) => Self { + level, + target: None, + field_names: Vec::new(), + }, + Err(_) => Self { + target: Some(String::from(part0)), + level: LevelFilter::TRACE, + field_names: Vec::new(), + }, + }) + } +} + +// === impl ParseError === + +impl ParseError { + #[cfg(feature = "env-filter")] + pub(crate) fn new() -> Self { + ParseError { + kind: ParseErrorKind::Other(None), + } + } + + pub(crate) fn msg(s: &'static str) -> Self { + ParseError { + kind: ParseErrorKind::Other(Some(s)), + } + } +} + +impl fmt::Display for ParseError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self.kind { + ParseErrorKind::Other(None) => f.pad("invalid filter directive"), + ParseErrorKind::Other(Some(msg)) => write!(f, "invalid filter directive: {}", msg), + ParseErrorKind::Level(ref l) => l.fmt(f), + #[cfg(feature = "std")] + ParseErrorKind::Field(ref e) => write!(f, "invalid field filter: {}", e), + } + } +} + +#[cfg(feature = "std")] +impl std::error::Error for ParseError { + fn description(&self) -> &str { + "invalid filter directive" + } + + fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { + match self.kind { + ParseErrorKind::Other(_) => None, + ParseErrorKind::Level(ref l) => Some(l), + ParseErrorKind::Field(ref n) => Some(n.as_ref()), + } + } +} + +#[cfg(feature = "std")] +impl From<Box<dyn std::error::Error + Send + Sync>> for ParseError { + fn from(e: Box<dyn std::error::Error + Send + Sync>) -> Self { + Self { + kind: ParseErrorKind::Field(e), + } + } +} + +impl From<level::ParseError> for ParseError { + fn from(l: level::ParseError) -> Self { + Self { + kind: ParseErrorKind::Level(l), + } + } +} |