Struct log::Metadata

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pub struct Metadata<'a> { /* private fields */ }
Expand description

Metadata about a log message.

§Use

Metadata structs are created when users of the library use logging macros.

They are consumed by implementations of the Log trait in the enabled method.

Records use Metadata to determine the log message’s severity and target.

Users should use the log_enabled! macro in their code to avoid constructing expensive log messages.

§Examples

use log::{Record, Level, Metadata};

struct MyLogger;

impl log::Log for MyLogger {
    fn enabled(&self, metadata: &Metadata) -> bool {
        metadata.level() <= Level::Info
    }

    fn log(&self, record: &Record) {
        if self.enabled(record.metadata()) {
            println!("{} - {}", record.level(), record.args());
        }
    }
    fn flush(&self) {}
}

Implementations§

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impl<'a> Metadata<'a>

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pub fn builder() -> MetadataBuilder<'a>

Returns a new builder.

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pub fn level(&self) -> Level

The verbosity level of the message.

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pub fn target(&self) -> &'a str

The name of the target of the directive.

Trait Implementations§

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impl<'a> Clone for Metadata<'a>

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fn clone(&self) -> Metadata<'a>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'a> Debug for Metadata<'a>

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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> Hash for Metadata<'a>

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'a> Ord for Metadata<'a>

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fn cmp(&self, other: &Metadata<'a>) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl<'a> PartialEq for Metadata<'a>

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fn eq(&self, other: &Metadata<'a>) -> 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<'a> PartialOrd for Metadata<'a>

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fn partial_cmp(&self, other: &Metadata<'a>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'a> Eq for Metadata<'a>

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impl<'a> StructuralPartialEq for Metadata<'a>

Auto Trait Implementations§

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impl<'a> Freeze for Metadata<'a>

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impl<'a> RefUnwindSafe for Metadata<'a>

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impl<'a> Send for Metadata<'a>

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impl<'a> Sync for Metadata<'a>

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impl<'a> Unpin for Metadata<'a>

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impl<'a> UnwindSafe for Metadata<'a>

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, 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.