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use crate::{DeferredNow, FormatFunction};
use log::Record;
/// Writes to a single log output stream.
///
/// Boxed instances of `LogWriter` can be used as additional log targets
/// (see [writers](crate::writers) for more details).
pub trait LogWriter: Sync + Send {
/// Writes out a log line.
///
/// # Errors
///
/// [`std::io::Error`]
fn write(&self, now: &mut DeferredNow, record: &Record) -> std::io::Result<()>;
/// Flushes any buffered records.
///
/// # Errors
///
/// [`std::io::Error`]
fn flush(&self) -> std::io::Result<()>;
/// Provides the maximum log level that is to be written.
fn max_log_level(&self) -> log::LevelFilter {
log::LevelFilter::Trace
}
/// Sets the format function.
///
/// Defaults to [`default_format`](crate::default_format),
/// but can be changed with a call to
/// [`Logger::format_for_writer`](crate::Logger::format_for_writer).
///
/// The default implementation is a no-op.
fn format(&mut self, format: FormatFunction) {
let _ = format;
}
/// Cleanup open resources, if necessary.
fn shutdown(&self) {}
/// Takes a vec with three patterns per line that represent the log out,
/// compares the written log with the expected lines,
/// and asserts that both are in sync.
///
/// This function is not meant for productive code, only for tests.
#[doc(hidden)]
fn validate_logs(&self, _expected: &[(&'static str, &'static str, &'static str)]) {
unimplemented!("only useful for tests");
}
}