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//! Span and `Event` key-value data. //! //! Spans and events may be annotated with key-value data, referred to as known //! as _fields_. These fields consist of a mapping from a key (corresponding to //! a `&str` but represented internally as an array index) to a [`Value`]. //! //! # `Value`s and `Subscriber`s //! //! `Subscriber`s consume `Value`s as fields attached to [span]s or [`Event`]s. //! The set of field keys on a given span or is defined on its [`Metadata`]. //! When a span is created, it provides [`Attributes`] to the `Subscriber`'s //! [`new_span`] method, containing any fields whose values were provided when //! the span was created; and may call the `Subscriber`'s [`record`] method //! with additional [`Record`]s if values are added for more of its fields. //! Similarly, the [`Event`] type passed to the subscriber's [`event`] method //! will contain any fields attached to each event. //! //! `tracing` represents values as either one of a set of Rust primitives //! (`i64`, `u64`, `bool`, and `&str`) or using a `fmt::Display` or `fmt::Debug` //! implementation. `Subscriber`s are provided these primitive value types as //! `dyn Value` trait objects. //! //! These trait objects can be formatted using `fmt::Debug`, but may also be //! recorded as typed data by calling the [`Value::record`] method on these //! trait objects with a _visitor_ implementing the [`Visit`] trait. This trait //! represents the behavior used to record values of various types. For example, //! we might record integers by incrementing counters for their field names, //! rather than printing them. //! //! [`Value`]: trait.Value.html //! [span]: ../span/ //! [`Event`]: ../event/struct.Event.html //! [`Metadata`]: ../metadata/struct.Metadata.html //! [`Attributes`]: ../span/struct.Attributes.html //! [`Record`]: ../span/struct.Record.html //! [`new_span`]: ../subscriber/trait.Subscriber.html#method.new_span //! [`record`]: ../subscriber/trait.Subscriber.html#method.record //! [`event`]: ../subscriber/trait.Subscriber.html#method.event //! [`Value::record`]: trait.Value.html#method.record //! [`Visit`]: trait.Visit.html use crate::callsite; use crate::stdlib::{ borrow::Borrow, fmt, hash::{Hash, Hasher}, num, ops::Range, }; use self::private::ValidLen; /// An opaque key allowing _O_(1) access to a field in a `Span`'s key-value /// data. /// /// As keys are defined by the _metadata_ of a span, rather than by an /// individual instance of a span, a key may be used to access the same field /// across all instances of a given span with the same metadata. Thus, when a /// subscriber observes a new span, it need only access a field by name _once_, /// and use the key for that name for all other accesses. #[derive(Debug)] pub struct Field { i: usize, fields: FieldSet, } /// An empty field. /// /// This can be used to indicate that the value of a field is not currently /// present but will be recorded later. /// /// When a field's value is `Empty`. it will not be recorded. #[derive(Debug, Eq, PartialEq)] pub struct Empty; /// Describes the fields present on a span. pub struct FieldSet { /// The names of each field on the described span. names: &'static [&'static str], /// The callsite where the described span originates. callsite: callsite::Identifier, } /// A set of fields and values for a span. pub struct ValueSet<'a> { values: &'a [(&'a Field, Option<&'a (dyn Value + 'a)>)], fields: &'a FieldSet, } /// An iterator over a set of fields. #[derive(Debug)] pub struct Iter { idxs: Range<usize>, fields: FieldSet, } /// Visits typed values. /// /// An instance of `Visit` ("a visitor") represents the logic necessary to /// record field values of various types. When an implementor of [`Value`] is /// [recorded], it calls the appropriate method on the provided visitor to /// indicate the type that value should be recorded as. /// /// When a [`Subscriber`] implementation [records an `Event`] or a /// [set of `Value`s added to a `Span`], it can pass an `&mut Visit` to the /// `record` method on the provided [`ValueSet`] or [`Event`]. This visitor /// will then be used to record all the field-value pairs present on that /// `Event` or `ValueSet`. /// /// # Examples /// /// A simple visitor that writes to a string might be implemented like so: /// ``` /// # extern crate tracing_core as tracing; /// use std::fmt::{self, Write}; /// use tracing::field::{Value, Visit, Field}; /// pub struct StringVisitor<'a> { /// string: &'a mut String, /// } /// /// impl<'a> Visit for StringVisitor<'a> { /// fn record_debug(&mut self, field: &Field, value: &fmt::Debug) { /// write!(self.string, "{} = {:?}; ", field.name(), value).unwrap(); /// } /// } /// ``` /// This visitor will format each recorded value using `fmt::Debug`, and /// append the field name and formatted value to the provided string, /// regardless of the type of the recorded value. When all the values have /// been recorded, the `StringVisitor` may be dropped, allowing the string /// to be printed or stored in some other data structure. /// /// The `Visit` trait provides default implementations for `record_i64`, /// `record_u64`, `record_bool`, `record_str`, and `record_error`, which simply /// forward the recorded value to `record_debug`. Thus, `record_debug` is the /// only method which a `Visit` implementation *must* implement. However, /// visitors may override the default implementations of these functions in /// order to implement type-specific behavior. /// /// Additionally, when a visitor receives a value of a type it does not care /// about, it is free to ignore those values completely. For example, a /// visitor which only records numeric data might look like this: /// /// ``` /// # extern crate tracing_core as tracing; /// # use std::fmt::{self, Write}; /// # use tracing::field::{Value, Visit, Field}; /// pub struct SumVisitor { /// sum: i64, /// } /// /// impl Visit for SumVisitor { /// fn record_i64(&mut self, _field: &Field, value: i64) { /// self.sum += value; /// } /// /// fn record_u64(&mut self, _field: &Field, value: u64) { /// self.sum += value as i64; /// } /// /// fn record_debug(&mut self, _field: &Field, _value: &fmt::Debug) { /// // Do nothing /// } /// } /// ``` /// /// This visitor (which is probably not particularly useful) keeps a running /// sum of all the numeric values it records, and ignores all other values. A /// more practical example of recording typed values is presented in /// `examples/counters.rs`, which demonstrates a very simple metrics system /// implemented using `tracing`. /// /// <div class="information"> /// <div class="tooltip ignore" style="">ⓘ<span class="tooltiptext">Note</span></div> /// </div> /// <div class="example-wrap" style="display:inline-block"> /// <pre class="ignore" style="white-space:normal;font:inherit;"> /// <strong>Note</strong>: The <code>record_error</code> trait method is only /// available when the Rust standard library is present, as it requires the /// <code>std::error::Error</code> trait. /// </pre></div> /// /// [`Value`]: trait.Value.html /// [recorded]: trait.Value.html#method.record /// [`Subscriber`]: ../subscriber/trait.Subscriber.html /// [records an `Event`]: ../subscriber/trait.Subscriber.html#method.event /// [set of `Value`s added to a `Span`]: ../subscriber/trait.Subscriber.html#method.record /// [`Event`]: ../event/struct.Event.html /// [`ValueSet`]: struct.ValueSet.html pub trait Visit { /// Visit a signed 64-bit integer value. fn record_i64(&mut self, field: &Field, value: i64) { self.record_debug(field, &value) } /// Visit an unsigned 64-bit integer value. fn record_u64(&mut self, field: &Field, value: u64) { self.record_debug(field, &value) } /// Visit a boolean value. fn record_bool(&mut self, field: &Field, value: bool) { self.record_debug(field, &value) } /// Visit a string value. fn record_str(&mut self, field: &Field, value: &str) { self.record_debug(field, &value) } /// Records a type implementing `Error`. /// /// <div class="information"> /// <div class="tooltip ignore" style="">ⓘ<span class="tooltiptext">Note</span></div> /// </div> /// <div class="example-wrap" style="display:inline-block"> /// <pre class="ignore" style="white-space:normal;font:inherit;"> /// <strong>Note</strong>: This is only enabled when the Rust standard library is /// present. /// </pre> #[cfg(feature = "std")] #[cfg_attr(docsrs, doc(cfg(feature = "std")))] fn record_error(&mut self, field: &Field, value: &(dyn std::error::Error + 'static)) { self.record_debug(field, &format_args!("{}", value)) } /// Visit a value implementing `fmt::Debug`. fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug); } /// A field value of an erased type. /// /// Implementors of `Value` may call the appropriate typed recording methods on /// the [visitor] passed to their `record` method in order to indicate how /// their data should be recorded. /// /// [visitor]: trait.Visit.html pub trait Value: crate::sealed::Sealed { /// Visits this value with the given `Visitor`. fn record(&self, key: &Field, visitor: &mut dyn Visit); } /// A `Value` which serializes using `fmt::Display`. /// /// Uses `record_debug` in the `Value` implementation to /// avoid an unnecessary evaluation. #[derive(Clone)] pub struct DisplayValue<T: fmt::Display>(T); /// A `Value` which serializes as a string using `fmt::Debug`. #[derive(Clone)] pub struct DebugValue<T: fmt::Debug>(T); /// Wraps a type implementing `fmt::Display` as a `Value` that can be /// recorded using its `Display` implementation. pub fn display<T>(t: T) -> DisplayValue<T> where T: fmt::Display, { DisplayValue(t) } /// Wraps a type implementing `fmt::Debug` as a `Value` that can be /// recorded using its `Debug` implementation. pub fn debug<T>(t: T) -> DebugValue<T> where T: fmt::Debug, { DebugValue(t) } // ===== impl Visit ===== impl<'a, 'b> Visit for fmt::DebugStruct<'a, 'b> { fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { self.field(field.name(), value); } } impl<'a, 'b> Visit for fmt::DebugMap<'a, 'b> { fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { self.entry(&format_args!("{}", field), value); } } impl<F> Visit for F where F: FnMut(&Field, &dyn fmt::Debug), { fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { (self)(field, value) } } // ===== impl Value ===== macro_rules! impl_values { ( $( $record:ident( $( $whatever:tt)+ ) ),+ ) => { $( impl_value!{ $record( $( $whatever )+ ) } )+ } } macro_rules! ty_to_nonzero { (u8) => { NonZeroU8 }; (u16) => { NonZeroU16 }; (u32) => { NonZeroU32 }; (u64) => { NonZeroU64 }; (u128) => { NonZeroU128 }; (usize) => { NonZeroUsize }; (i8) => { NonZeroI8 }; (i16) => { NonZeroI16 }; (i32) => { NonZeroI32 }; (i64) => { NonZeroI64 }; (i128) => { NonZeroI128 }; (isize) => { NonZeroIsize }; } macro_rules! impl_one_value { (bool, $op:expr, $record:ident) => { impl_one_value!(normal, bool, $op, $record); }; ($value_ty:tt, $op:expr, $record:ident) => { impl_one_value!(normal, $value_ty, $op, $record); impl_one_value!(nonzero, $value_ty, $op, $record); }; (normal, $value_ty:tt, $op:expr, $record:ident) => { impl $crate::sealed::Sealed for $value_ty {} impl $crate::field::Value for $value_ty { fn record(&self, key: &$crate::field::Field, visitor: &mut dyn $crate::field::Visit) { visitor.$record(key, $op(*self)) } } }; (nonzero, $value_ty:tt, $op:expr, $record:ident) => { // This `use num::*;` is reported as unused because it gets emitted // for every single invocation of this macro, so there are multiple `use`s. // All but the first are useless indeed. // We need this import because we can't write a path where one part is // the `ty_to_nonzero!($value_ty)` invocation. #[allow(clippy::useless_attribute, unused)] use num::*; impl $crate::sealed::Sealed for ty_to_nonzero!($value_ty) {} impl $crate::field::Value for ty_to_nonzero!($value_ty) { fn record(&self, key: &$crate::field::Field, visitor: &mut dyn $crate::field::Visit) { visitor.$record(key, $op(self.get())) } } }; } macro_rules! impl_value { ( $record:ident( $( $value_ty:tt ),+ ) ) => { $( impl_one_value!($value_ty, |this: $value_ty| this, $record); )+ }; ( $record:ident( $( $value_ty:tt ),+ as $as_ty:ty) ) => { $( impl_one_value!($value_ty, |this: $value_ty| this as $as_ty, $record); )+ }; } // ===== impl Value ===== impl_values! { record_u64(u64), record_u64(usize, u32, u16, u8 as u64), record_i64(i64), record_i64(isize, i32, i16, i8 as i64), record_bool(bool) } impl<T: crate::sealed::Sealed> crate::sealed::Sealed for Wrapping<T> {} impl<T: crate::field::Value> crate::field::Value for Wrapping<T> { fn record(&self, key: &crate::field::Field, visitor: &mut dyn crate::field::Visit) { self.0.record(key, visitor) } } impl crate::sealed::Sealed for str {} impl Value for str { fn record(&self, key: &Field, visitor: &mut dyn Visit) { visitor.record_str(key, &self) } } #[cfg(feature = "std")] impl crate::sealed::Sealed for dyn std::error::Error + 'static {} #[cfg(feature = "std")] #[cfg_attr(docsrs, doc(cfg(feature = "std")))] impl Value for dyn std::error::Error + 'static { fn record(&self, key: &Field, visitor: &mut dyn Visit) { visitor.record_error(key, self) } } impl<'a, T: ?Sized> crate::sealed::Sealed for &'a T where T: Value + crate::sealed::Sealed + 'a {} impl<'a, T: ?Sized> Value for &'a T where T: Value + 'a, { fn record(&self, key: &Field, visitor: &mut dyn Visit) { (*self).record(key, visitor) } } impl<'a> crate::sealed::Sealed for fmt::Arguments<'a> {} impl<'a> Value for fmt::Arguments<'a> { fn record(&self, key: &Field, visitor: &mut dyn Visit) { visitor.record_debug(key, self) } } impl fmt::Debug for dyn Value { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { // We are only going to be recording the field value, so we don't // actually care about the field name here. struct NullCallsite; static NULL_CALLSITE: NullCallsite = NullCallsite; impl crate::callsite::Callsite for NullCallsite { fn set_interest(&self, _: crate::subscriber::Interest) { unreachable!("you somehow managed to register the null callsite?") } fn metadata(&self) -> &crate::Metadata<'_> { unreachable!("you somehow managed to access the null callsite?") } } static FIELD: Field = Field { i: 0, fields: FieldSet::new(&[], crate::identify_callsite!(&NULL_CALLSITE)), }; let mut res = Ok(()); self.record(&FIELD, &mut |_: &Field, val: &dyn fmt::Debug| { res = write!(f, "{:?}", val); }); res } } impl fmt::Display for dyn Value { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Debug::fmt(self, f) } } // ===== impl DisplayValue ===== impl<T: fmt::Display> crate::sealed::Sealed for DisplayValue<T> {} impl<T> Value for DisplayValue<T> where T: fmt::Display, { fn record(&self, key: &Field, visitor: &mut dyn Visit) { visitor.record_debug(key, &format_args!("{}", self.0)) } } impl<T: fmt::Display> fmt::Debug for DisplayValue<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{}", self.0) } } impl<T: fmt::Display> fmt::Display for DisplayValue<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(&self.0, f) } } // ===== impl DebugValue ===== impl<T: fmt::Debug> crate::sealed::Sealed for DebugValue<T> {} impl<T: fmt::Debug> Value for DebugValue<T> where T: fmt::Debug, { fn record(&self, key: &Field, visitor: &mut dyn Visit) { visitor.record_debug(key, &self.0) } } impl<T: fmt::Debug> fmt::Debug for DebugValue<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{:?}", self.0) } } impl crate::sealed::Sealed for Empty {} impl Value for Empty { #[inline] fn record(&self, _: &Field, _: &mut dyn Visit) {} } // ===== impl Field ===== impl Field { /// Returns an [`Identifier`] that uniquely identifies the [`Callsite`] /// which defines this field. /// /// [`Identifier`]: ../callsite/struct.Identifier.html /// [`Callsite`]: ../callsite/trait.Callsite.html #[inline] pub fn callsite(&self) -> callsite::Identifier { self.fields.callsite() } /// Returns a string representing the name of the field. pub fn name(&self) -> &'static str { self.fields.names[self.i] } } impl fmt::Display for Field { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.pad(self.name()) } } impl AsRef<str> for Field { fn as_ref(&self) -> &str { self.name() } } impl PartialEq for Field { fn eq(&self, other: &Self) -> bool { self.callsite() == other.callsite() && self.i == other.i } } impl Eq for Field {} impl Hash for Field { fn hash<H>(&self, state: &mut H) where H: Hasher, { self.callsite().hash(state); self.i.hash(state); } } impl Clone for Field { fn clone(&self) -> Self { Field { i: self.i, fields: FieldSet { names: self.fields.names, callsite: self.fields.callsite(), }, } } } // ===== impl FieldSet ===== impl FieldSet { /// Constructs a new `FieldSet` with the given array of field names and callsite. pub const fn new(names: &'static [&'static str], callsite: callsite::Identifier) -> Self { Self { names, callsite } } /// Returns an [`Identifier`] that uniquely identifies the [`Callsite`] /// which defines this set of fields.. /// /// [`Identifier`]: ../callsite/struct.Identifier.html /// [`Callsite`]: ../callsite/trait.Callsite.html pub(crate) fn callsite(&self) -> callsite::Identifier { callsite::Identifier(self.callsite.0) } /// Returns the [`Field`] named `name`, or `None` if no such field exists. /// /// [`Field`]: ../struct.Field.html pub fn field<Q: ?Sized>(&self, name: &Q) -> Option<Field> where Q: Borrow<str>, { let name = &name.borrow(); self.names.iter().position(|f| f == name).map(|i| Field { i, fields: FieldSet { names: self.names, callsite: self.callsite(), }, }) } /// Returns `true` if `self` contains the given `field`. /// /// <div class="information"> /// <div class="tooltip ignore" style="">ⓘ<span class="tooltiptext">Note</span></div> /// </div> /// <div class="example-wrap" style="display:inline-block"> /// <pre class="ignore" style="white-space:normal;font:inherit;"> /// <strong>Note</strong>: If <code>field</code> shares a name with a field /// in this <code>FieldSet</code>, but was created by a <code>FieldSet</code> /// with a different callsite, this <code>FieldSet</code> does <em>not</em> /// contain it. This is so that if two separate span callsites define a field /// named "foo", the <code>Field</code> corresponding to "foo" for each /// of those callsites are not equivalent. /// </pre></div> pub fn contains(&self, field: &Field) -> bool { field.callsite() == self.callsite() && field.i <= self.len() } /// Returns an iterator over the `Field`s in this `FieldSet`. pub fn iter(&self) -> Iter { let idxs = 0..self.len(); Iter { idxs, fields: FieldSet { names: self.names, callsite: self.callsite(), }, } } /// Returns a new `ValueSet` with entries for this `FieldSet`'s values. /// /// Note that a `ValueSet` may not be constructed with arrays of over 32 /// elements. #[doc(hidden)] pub fn value_set<'v, V>(&'v self, values: &'v V) -> ValueSet<'v> where V: ValidLen<'v>, { ValueSet { fields: self, values: &values.borrow()[..], } } /// Returns the number of fields in this `FieldSet`. #[inline] pub fn len(&self) -> usize { self.names.len() } /// Returns whether or not this `FieldSet` has fields. #[inline] pub fn is_empty(&self) -> bool { self.names.is_empty() } } impl<'a> IntoIterator for &'a FieldSet { type IntoIter = Iter; type Item = Field; #[inline] fn into_iter(self) -> Self::IntoIter { self.iter() } } impl fmt::Debug for FieldSet { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("FieldSet") .field("names", &self.names) .field("callsite", &self.callsite) .finish() } } impl fmt::Display for FieldSet { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_set() .entries(self.names.iter().map(display)) .finish() } } // ===== impl Iter ===== impl Iterator for Iter { type Item = Field; fn next(&mut self) -> Option<Field> { let i = self.idxs.next()?; Some(Field { i, fields: FieldSet { names: self.fields.names, callsite: self.fields.callsite(), }, }) } } // ===== impl ValueSet ===== impl<'a> ValueSet<'a> { /// Returns an [`Identifier`] that uniquely identifies the [`Callsite`] /// defining the fields this `ValueSet` refers to. /// /// [`Identifier`]: ../callsite/struct.Identifier.html /// [`Callsite`]: ../callsite/trait.Callsite.html #[inline] pub fn callsite(&self) -> callsite::Identifier { self.fields.callsite() } /// Visits all the fields in this `ValueSet` with the provided [visitor]. /// /// [visitor]: ../trait.Visit.html pub(crate) fn record(&self, visitor: &mut dyn Visit) { let my_callsite = self.callsite(); for (field, value) in self.values { if field.callsite() != my_callsite { continue; } if let Some(value) = value { value.record(field, visitor); } } } /// Returns `true` if this `ValueSet` contains a value for the given `Field`. pub(crate) fn contains(&self, field: &Field) -> bool { field.callsite() == self.callsite() && self .values .iter() .any(|(key, val)| *key == field && val.is_some()) } /// Returns true if this `ValueSet` contains _no_ values. pub(crate) fn is_empty(&self) -> bool { let my_callsite = self.callsite(); self.values .iter() .all(|(key, val)| val.is_none() || key.callsite() != my_callsite) } pub(crate) fn field_set(&self) -> &FieldSet { self.fields } } impl<'a> fmt::Debug for ValueSet<'a> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.values .iter() .fold(&mut f.debug_struct("ValueSet"), |dbg, (key, v)| { if let Some(val) = v { val.record(key, dbg); } dbg }) .field("callsite", &self.callsite()) .finish() } } impl<'a> fmt::Display for ValueSet<'a> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.values .iter() .fold(&mut f.debug_map(), |dbg, (key, v)| { if let Some(val) = v { val.record(key, dbg); } dbg }) .finish() } } // ===== impl ValidLen ===== mod private { use super::*; /// Marker trait implemented by arrays which are of valid length to /// construct a `ValueSet`. /// /// `ValueSet`s may only be constructed from arrays containing 32 or fewer /// elements, to ensure the array is small enough to always be allocated on the /// stack. This trait is only implemented by arrays of an appropriate length, /// ensuring that the correct size arrays are used at compile-time. pub trait ValidLen<'a>: Borrow<[(&'a Field, Option<&'a (dyn Value + 'a)>)]> {} } macro_rules! impl_valid_len { ( $( $len:tt ),+ ) => { $( impl<'a> private::ValidLen<'a> for [(&'a Field, Option<&'a (dyn Value + 'a)>); $len] {} )+ } } impl_valid_len! { 0, 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 } #[cfg(test)] mod test { use super::*; use crate::metadata::{Kind, Level, Metadata}; use crate::stdlib::{borrow::ToOwned, string::String}; struct TestCallsite1; static TEST_CALLSITE_1: TestCallsite1 = TestCallsite1; static TEST_META_1: Metadata<'static> = metadata! { name: "field_test1", target: module_path!(), level: Level::INFO, fields: &["foo", "bar", "baz"], callsite: &TEST_CALLSITE_1, kind: Kind::SPAN, }; impl crate::callsite::Callsite for TestCallsite1 { fn set_interest(&self, _: crate::subscriber::Interest) { unimplemented!() } fn metadata(&self) -> &Metadata<'_> { &TEST_META_1 } } struct TestCallsite2; static TEST_CALLSITE_2: TestCallsite2 = TestCallsite2; static TEST_META_2: Metadata<'static> = metadata! { name: "field_test2", target: module_path!(), level: Level::INFO, fields: &["foo", "bar", "baz"], callsite: &TEST_CALLSITE_2, kind: Kind::SPAN, }; impl crate::callsite::Callsite for TestCallsite2 { fn set_interest(&self, _: crate::subscriber::Interest) { unimplemented!() } fn metadata(&self) -> &Metadata<'_> { &TEST_META_2 } } #[test] fn value_set_with_no_values_is_empty() { let fields = TEST_META_1.fields(); let values = &[ (&fields.field("foo").unwrap(), None), (&fields.field("bar").unwrap(), None), (&fields.field("baz").unwrap(), None), ]; let valueset = fields.value_set(values); assert!(valueset.is_empty()); } #[test] fn empty_value_set_is_empty() { let fields = TEST_META_1.fields(); let valueset = fields.value_set(&[]); assert!(valueset.is_empty()); } #[test] fn value_sets_with_fields_from_other_callsites_are_empty() { let fields = TEST_META_1.fields(); let values = &[ (&fields.field("foo").unwrap(), Some(&1 as &dyn Value)), (&fields.field("bar").unwrap(), Some(&2 as &dyn Value)), (&fields.field("baz").unwrap(), Some(&3 as &dyn Value)), ]; let valueset = TEST_META_2.fields().value_set(values); assert!(valueset.is_empty()) } #[test] fn sparse_value_sets_are_not_empty() { let fields = TEST_META_1.fields(); let values = &[ (&fields.field("foo").unwrap(), None), (&fields.field("bar").unwrap(), Some(&57 as &dyn Value)), (&fields.field("baz").unwrap(), None), ]; let valueset = fields.value_set(values); assert!(!valueset.is_empty()); } #[test] fn fields_from_other_callsets_are_skipped() { let fields = TEST_META_1.fields(); let values = &[ (&fields.field("foo").unwrap(), None), ( &TEST_META_2.fields().field("bar").unwrap(), Some(&57 as &dyn Value), ), (&fields.field("baz").unwrap(), None), ]; struct MyVisitor; impl Visit for MyVisitor { fn record_debug(&mut self, field: &Field, _: &dyn (crate::stdlib::fmt::Debug)) { assert_eq!(field.callsite(), TEST_META_1.callsite()) } } let valueset = fields.value_set(values); valueset.record(&mut MyVisitor); } #[test] fn empty_fields_are_skipped() { let fields = TEST_META_1.fields(); let values = &[ (&fields.field("foo").unwrap(), Some(&Empty as &dyn Value)), (&fields.field("bar").unwrap(), Some(&57 as &dyn Value)), (&fields.field("baz").unwrap(), Some(&Empty as &dyn Value)), ]; struct MyVisitor; impl Visit for MyVisitor { fn record_debug(&mut self, field: &Field, _: &dyn (crate::stdlib::fmt::Debug)) { assert_eq!(field.name(), "bar") } } let valueset = fields.value_set(values); valueset.record(&mut MyVisitor); } #[test] fn record_debug_fn() { let fields = TEST_META_1.fields(); let values = &[ (&fields.field("foo").unwrap(), Some(&1 as &dyn Value)), (&fields.field("bar").unwrap(), Some(&2 as &dyn Value)), (&fields.field("baz").unwrap(), Some(&3 as &dyn Value)), ]; let valueset = fields.value_set(values); let mut result = String::new(); valueset.record(&mut |_: &Field, value: &dyn fmt::Debug| { use crate::stdlib::fmt::Write; write!(&mut result, "{:?}", value).unwrap(); }); assert_eq!(result, "123".to_owned()); } }