pub struct FieldSet { /* private fields */ }
Expand description

Describes the fields present on a span.

Equality

In well-behaved applications, two FieldSets initialized with equal callsite identifiers will have identical fields. Consequently, in release builds, FieldSet::eq only checks that its arguments have equal callsites. However, the equality of field names is checked in debug builds.

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impl FieldSet

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pub const fn new(names: &'static [&'static str], callsite: Identifier) -> Self

Constructs a new FieldSet with the given array of field names and callsite.

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pub fn field<Q>(&self, name: &Q) -> Option<Field>
where Q: Borrow<str> + ?Sized,

Returns the Field named name, or None if no such field exists.

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pub fn contains(&self, field: &Field) -> bool

Returns true if self contains the given field.

Note: If field shares a name with a field
in this FieldSet, but was created by a FieldSet
with a different callsite, this FieldSet does not
contain it. This is so that if two separate span callsites define a field
named "foo", the Field corresponding to "foo" for each
of those callsites are not equivalent.
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pub fn iter(&self) -> Iter

Returns an iterator over the Fields in this FieldSet.

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pub fn len(&self) -> usize

Returns the number of fields in this FieldSet.

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pub fn is_empty(&self) -> bool

Returns whether or not this FieldSet has fields.

Trait Implementations§

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impl Debug for FieldSet

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Display for FieldSet

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<'a> IntoIterator for &'a FieldSet

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type IntoIter = Iter

Which kind of iterator are we turning this into?
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type Item = Field

The type of the elements being iterated over.
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fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
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impl PartialEq for FieldSet

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fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Eq for FieldSet

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.