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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
//! Rust Logger implementation
//!
//! This is responsible for taking logs from the rust log crate and forwarding them to a
//! foreign_logger::Logger instance.
use crate::foreign_logger::AppServicesLogger as ForeignLogger;
use parking_lot::RwLock;
use std::sync::{
atomic::{AtomicBool, Ordering},
Once,
};
// ForeignLogger to forward to
static RUST_LOGGER: Logger = Logger::new();
// Handles calling `log::set_logger`, which can only be called once.
static INIT: Once = Once::new();
struct Logger {
foreign_logger: RwLock<Option<Box<dyn ForeignLogger>>>,
is_enabled: AtomicBool,
}
impl Logger {
const fn new() -> Self {
Self {
foreign_logger: RwLock::new(None),
is_enabled: AtomicBool::new(false),
}
}
fn set_foreign_logger(&self, foreign_logger: Option<Box<dyn ForeignLogger>>) {
self.is_enabled
.store(foreign_logger.is_some(), Ordering::Relaxed);
*self.foreign_logger.write() = foreign_logger;
}
}
impl log::Log for Logger {
fn enabled(&self, _: &log::Metadata<'_>) -> bool {
self.is_enabled.load(Ordering::Relaxed)
}
fn log(&self, record: &log::Record<'_>) {
if let Some(foreign_logger) = &*self.foreign_logger.read() {
foreign_logger.log(record.into())
}
}
fn flush(&self) {}
}
pub fn set_foreign_logger(foreign_logger: Option<Box<dyn ForeignLogger>>) {
INIT.call_once(|| {
// This should be the only component that calls `log::set_logger()`. If not, then
// panic'ing seems reasonable.
log::set_logger(&RUST_LOGGER).expect(
"Failed to initialize rust-log-forwarder::Logger, other log implementation already initialized?",
);
});
RUST_LOGGER.set_foreign_logger(foreign_logger);
}