1use crate::filter::level::{self, LevelFilter};
2#[cfg(not(feature = "smallvec"))]
3use alloc::vec;
4#[cfg(not(feature = "std"))]
5use alloc::{string::String, vec::Vec};
6
7use core::{cmp::Ordering, fmt, iter::FromIterator, slice, str::FromStr};
8use tracing_core::{Level, Metadata};
9/// Indicates that a string could not be parsed as a filtering directive.
10#[derive(Debug)]
11pub struct ParseError {
12 kind: ParseErrorKind,
13}
14
15/// A directive which will statically enable or disable a given callsite.
16///
17/// Unlike a dynamic directive, this can be cached by the callsite.
18#[derive(Debug, PartialEq, Eq, Clone)]
19pub(crate) struct StaticDirective {
20 pub(in crate::filter) target: Option<String>,
21 pub(in crate::filter) field_names: Vec<String>,
22 pub(in crate::filter) level: LevelFilter,
23}
24
25#[cfg(feature = "smallvec")]
26pub(crate) type FilterVec<T> = smallvec::SmallVec<[T; 8]>;
27#[cfg(not(feature = "smallvec"))]
28pub(crate) type FilterVec<T> = Vec<T>;
29
30#[derive(Debug, PartialEq, Clone)]
31pub(in crate::filter) struct DirectiveSet<T> {
32 directives: FilterVec<T>,
33 pub(in crate::filter) max_level: LevelFilter,
34}
35
36pub(in crate::filter) trait Match {
37 fn cares_about(&self, meta: &Metadata<'_>) -> bool;
38 fn level(&self) -> &LevelFilter;
39}
40
41#[derive(Debug)]
42enum ParseErrorKind {
43 #[cfg(feature = "std")]
44 Field(Box<dyn std::error::Error + Send + Sync>),
45 Level(level::ParseError),
46 Other(Option<&'static str>),
47}
48
49// === impl DirectiveSet ===
50
51impl<T> DirectiveSet<T> {
52 // this is only used by `env-filter`.
53 #[cfg(all(feature = "std", feature = "env-filter"))]
54 pub(crate) fn is_empty(&self) -> bool {
55 self.directives.is_empty()
56 }
57
58 pub(crate) fn iter(&self) -> slice::Iter<'_, T> {
59 self.directives.iter()
60 }
61}
62
63impl<T: Ord> Default for DirectiveSet<T> {
64 fn default() -> Self {
65 Self {
66 directives: FilterVec::new(),
67 max_level: LevelFilter::OFF,
68 }
69 }
70}
71
72impl<T: Match + Ord> DirectiveSet<T> {
73 pub(crate) fn directives(&self) -> impl Iterator<Item = &T> {
74 self.directives.iter()
75 }
76
77 pub(crate) fn directives_for<'a>(
78 &'a self,
79 metadata: &'a Metadata<'a>,
80 ) -> impl Iterator<Item = &'a T> + 'a {
81 self.directives().filter(move |d| d.cares_about(metadata))
82 }
83
84 pub(crate) fn add(&mut self, directive: T) {
85 // does this directive enable a more verbose level than the current
86 // max? if so, update the max level.
87 let level = *directive.level();
88 if level > self.max_level {
89 self.max_level = level;
90 }
91 // insert the directive into the vec of directives, ordered by
92 // specificity (length of target + number of field filters). this
93 // ensures that, when finding a directive to match a span or event, we
94 // search the directive set in most specific first order.
95 match self.directives.binary_search(&directive) {
96 Ok(i) => self.directives[i] = directive,
97 Err(i) => self.directives.insert(i, directive),
98 }
99 }
100
101 #[cfg(test)]
102 pub(in crate::filter) fn into_vec(self) -> FilterVec<T> {
103 self.directives
104 }
105}
106
107impl<T: Match + Ord> FromIterator<T> for DirectiveSet<T> {
108 fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
109 let mut this: DirectiveSet = Self::default();
110 this.extend(iter);
111 this
112 }
113}
114
115impl<T: Match + Ord> Extend<T> for DirectiveSet<T> {
116 fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
117 for directive: T in iter.into_iter() {
118 self.add(directive);
119 }
120 }
121}
122
123impl<T> IntoIterator for DirectiveSet<T> {
124 type Item = T;
125
126 #[cfg(feature = "smallvec")]
127 type IntoIter = smallvec::IntoIter<[T; 8]>;
128 #[cfg(not(feature = "smallvec"))]
129 type IntoIter = vec::IntoIter<T>;
130
131 fn into_iter(self) -> Self::IntoIter {
132 self.directives.into_iter()
133 }
134}
135
136// === impl Statics ===
137
138impl DirectiveSet<StaticDirective> {
139 pub(crate) fn enabled(&self, meta: &Metadata<'_>) -> bool {
140 let level = meta.level();
141 match self.directives_for(meta).next() {
142 Some(d) => d.level >= *level,
143 None => false,
144 }
145 }
146
147 /// Same as `enabled` above, but skips `Directive`'s with fields.
148 pub(crate) fn target_enabled(&self, target: &str, level: &Level) -> bool {
149 match self.directives_for_target(target).next() {
150 Some(d) => d.level >= *level,
151 None => false,
152 }
153 }
154
155 pub(crate) fn directives_for_target<'a>(
156 &'a self,
157 target: &'a str,
158 ) -> impl Iterator<Item = &'a StaticDirective> + 'a {
159 self.directives()
160 .filter(move |d| d.cares_about_target(target))
161 }
162}
163
164// === impl StaticDirective ===
165
166impl StaticDirective {
167 pub(in crate::filter) fn new(
168 target: Option<String>,
169 field_names: Vec<String>,
170 level: LevelFilter,
171 ) -> Self {
172 Self {
173 target,
174 field_names,
175 level,
176 }
177 }
178
179 pub(in crate::filter) fn cares_about_target(&self, to_check: &str) -> bool {
180 // Does this directive have a target filter, and does it match the
181 // metadata's target?
182 if let Some(ref target) = self.target {
183 if !to_check.starts_with(&target[..]) {
184 return false;
185 }
186 }
187
188 if !self.field_names.is_empty() {
189 return false;
190 }
191
192 true
193 }
194}
195
196impl Ord for StaticDirective {
197 fn cmp(&self, other: &StaticDirective) -> Ordering {
198 // We attempt to order directives by how "specific" they are. This
199 // ensures that we try the most specific directives first when
200 // attempting to match a piece of metadata.
201
202 // First, we compare based on whether a target is specified, and the
203 // lengths of those targets if both have targets.
204 let ordering = self
205 .target
206 .as_ref()
207 .map(String::len)
208 .cmp(&other.target.as_ref().map(String::len))
209 // Then we compare how many field names are matched by each directive.
210 .then_with(|| self.field_names.len().cmp(&other.field_names.len()))
211 // Finally, we fall back to lexicographical ordering if the directives are
212 // equally specific. Although this is no longer semantically important,
213 // we need to define a total ordering to determine the directive's place
214 // in the BTreeMap.
215 .then_with(|| {
216 self.target
217 .cmp(&other.target)
218 .then_with(|| self.field_names[..].cmp(&other.field_names[..]))
219 })
220 .reverse();
221
222 #[cfg(debug_assertions)]
223 {
224 if ordering == Ordering::Equal {
225 debug_assert_eq!(
226 self.target, other.target,
227 "invariant violated: Ordering::Equal must imply a.target == b.target"
228 );
229 debug_assert_eq!(
230 self.field_names, other.field_names,
231 "invariant violated: Ordering::Equal must imply a.field_names == b.field_names"
232 );
233 }
234 }
235
236 ordering
237 }
238}
239
240impl PartialOrd for StaticDirective {
241 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
242 Some(self.cmp(other))
243 }
244}
245
246impl Match for StaticDirective {
247 fn cares_about(&self, meta: &Metadata<'_>) -> bool {
248 // Does this directive have a target filter, and does it match the
249 // metadata's target?
250 if let Some(ref target) = self.target {
251 if !meta.target().starts_with(&target[..]) {
252 return false;
253 }
254 }
255
256 if meta.is_event() && !self.field_names.is_empty() {
257 let fields = meta.fields();
258 for name in &self.field_names {
259 if fields.field(name).is_none() {
260 return false;
261 }
262 }
263 }
264
265 true
266 }
267
268 fn level(&self) -> &LevelFilter {
269 &self.level
270 }
271}
272
273impl Default for StaticDirective {
274 fn default() -> Self {
275 StaticDirective {
276 target: None,
277 field_names: Vec::new(),
278 level: LevelFilter::ERROR,
279 }
280 }
281}
282
283impl fmt::Display for StaticDirective {
284 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
285 let mut wrote_any = false;
286 if let Some(ref target) = self.target {
287 fmt::Display::fmt(target, f)?;
288 wrote_any = true;
289 }
290
291 if !self.field_names.is_empty() {
292 f.write_str("[")?;
293
294 let mut fields = self.field_names.iter();
295 if let Some(field) = fields.next() {
296 write!(f, "{{{}", field)?;
297 for field in fields {
298 write!(f, ",{}", field)?;
299 }
300 f.write_str("}")?;
301 }
302
303 f.write_str("]")?;
304 wrote_any = true;
305 }
306
307 if wrote_any {
308 f.write_str("=")?;
309 }
310
311 fmt::Display::fmt(&self.level, f)
312 }
313}
314
315impl FromStr for StaticDirective {
316 type Err = ParseError;
317
318 fn from_str(s: &str) -> Result<Self, Self::Err> {
319 // This method parses a filtering directive in one of the following
320 // forms:
321 //
322 // * `foo=trace` (TARGET=LEVEL)
323 // * `foo[{bar,baz}]=info` (TARGET[{FIELD,+}]=LEVEL)
324 // * `trace` (bare LEVEL)
325 // * `foo` (bare TARGET)
326 let mut split = s.split('=');
327 let part0 = split
328 .next()
329 .ok_or_else(|| ParseError::msg("string must not be empty"))?;
330
331 // Directive includes an `=`:
332 // * `foo=trace`
333 // * `foo[{bar}]=trace`
334 // * `foo[{bar,baz}]=trace`
335 if let Some(part1) = split.next() {
336 if split.next().is_some() {
337 return Err(ParseError::msg(
338 "too many '=' in filter directive, expected 0 or 1",
339 ));
340 }
341
342 let mut split = part0.split("[{");
343 let target = split.next().map(String::from);
344 let mut field_names = Vec::new();
345 // Directive includes fields:
346 // * `foo[{bar}]=trace`
347 // * `foo[{bar,baz}]=trace`
348 if let Some(maybe_fields) = split.next() {
349 if split.next().is_some() {
350 return Err(ParseError::msg(
351 "too many '[{' in filter directive, expected 0 or 1",
352 ));
353 }
354
355 if !maybe_fields.ends_with("}]") {
356 return Err(ParseError::msg("expected fields list to end with '}]'"));
357 }
358
359 let fields = maybe_fields
360 .trim_end_matches("}]")
361 .split(',')
362 .filter_map(|s| {
363 if s.is_empty() {
364 None
365 } else {
366 Some(String::from(s))
367 }
368 });
369 field_names.extend(fields);
370 };
371 let level = part1.parse()?;
372 return Ok(Self {
373 level,
374 field_names,
375 target,
376 });
377 }
378
379 // Okay, the part after the `=` was empty, the directive is either a
380 // bare level or a bare target.
381 // * `foo`
382 // * `info`
383 Ok(match part0.parse::<LevelFilter>() {
384 Ok(level) => Self {
385 level,
386 target: None,
387 field_names: Vec::new(),
388 },
389 Err(_) => Self {
390 target: Some(String::from(part0)),
391 level: LevelFilter::TRACE,
392 field_names: Vec::new(),
393 },
394 })
395 }
396}
397
398// === impl ParseError ===
399
400impl ParseError {
401 #[cfg(all(feature = "std", feature = "env-filter"))]
402 pub(crate) fn new() -> Self {
403 ParseError {
404 kind: ParseErrorKind::Other(None),
405 }
406 }
407
408 pub(crate) fn msg(s: &'static str) -> Self {
409 ParseError {
410 kind: ParseErrorKind::Other(Some(s)),
411 }
412 }
413}
414
415impl fmt::Display for ParseError {
416 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
417 match self.kind {
418 ParseErrorKind::Other(None) => f.pad("invalid filter directive"),
419 ParseErrorKind::Other(Some(msg: &'static str)) => write!(f, "invalid filter directive: {}", msg),
420 ParseErrorKind::Level(ref l: &ParseLevelFilterError) => l.fmt(f),
421 #[cfg(feature = "std")]
422 ParseErrorKind::Field(ref e: &Box) => write!(f, "invalid field filter: {}", e),
423 }
424 }
425}
426
427#[cfg(feature = "std")]
428impl std::error::Error for ParseError {
429 fn description(&self) -> &str {
430 "invalid filter directive"
431 }
432
433 fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
434 match self.kind {
435 ParseErrorKind::Other(_) => None,
436 ParseErrorKind::Level(ref l: &ParseLevelFilterError) => Some(l),
437 ParseErrorKind::Field(ref n: &Box) => Some(n.as_ref()),
438 }
439 }
440}
441
442#[cfg(feature = "std")]
443impl From<Box<dyn std::error::Error + Send + Sync>> for ParseError {
444 fn from(e: Box<dyn std::error::Error + Send + Sync>) -> Self {
445 Self {
446 kind: ParseErrorKind::Field(e),
447 }
448 }
449}
450
451impl From<level::ParseError> for ParseError {
452 fn from(l: level::ParseError) -> Self {
453 Self {
454 kind: ParseErrorKind::Level(l),
455 }
456 }
457}
458