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extern crate log;
use log::Log;
use log::Metadata;
use log::Record;
use std::cell::RefCell;
use std::mem;
use std::rc::Rc;
use std::sync::Arc;
pub struct Logger {
underlying: Box<dyn Log>,
}
impl Logger {
pub fn new(underlying: Box<dyn Log>) -> Logger {
Logger { underlying }
}
}
impl Log for Logger {
fn enabled(&self, metadata: &Metadata) -> bool {
self.underlying.enabled(metadata)
}
fn log(&self, record: &Record) {
get(|ndc| {
if ndc.is_empty() {
self.underlying.log(record)
} else {
self.underlying.log(
&Record::builder()
.metadata(record.metadata().clone())
.args(format_args!("[{}] {}", ndc, record.args()))
.module_path(record.module_path())
.file(record.file())
.line(record.line())
.build(),
);
}
})
}
fn flush(&self) {
self.underlying.flush()
}
}
pub fn set_boxed_logger(logger: Box<dyn Log>) -> Result<(), log::SetLoggerError> {
log::set_boxed_logger(Box::new(Logger::new(logger)))
}
#[derive(Debug, Clone)]
pub enum Ndc {
Str(&'static str),
String(String),
Rc(Rc<String>),
Arc(Arc<String>),
}
impl Default for Ndc {
fn default() -> Self {
Ndc::Str("")
}
}
impl Ndc {
fn to_str(&self) -> &str {
match self {
Ndc::Str(s) => s,
Ndc::String(s) => &s,
Ndc::Rc(s) => &**s,
Ndc::Arc(s) => &**s,
}
}
}
impl From<&'static str> for Ndc {
fn from(s: &'static str) -> Self {
Ndc::Str(s)
}
}
impl From<String> for Ndc {
fn from(s: String) -> Self {
Ndc::String(s)
}
}
impl From<Rc<String>> for Ndc {
fn from(s: Rc<String>) -> Self {
Ndc::Rc(s)
}
}
impl From<Arc<String>> for Ndc {
fn from(s: Arc<String>) -> Self {
Ndc::Arc(s)
}
}
thread_local! {
static NDC: RefCell<Ndc> = RefCell::new(Ndc::Str(""));
}
#[must_use]
pub struct SetGuard {
ndc: Ndc,
}
impl Drop for SetGuard {
fn drop(&mut self) {
set(mem::replace(&mut self.ndc, Default::default()));
}
}
pub fn set<S: Into<Ndc>>(ndc: S) {
replace(ndc);
}
pub fn replace<S: Into<Ndc>>(ndc: S) -> Ndc {
NDC.with(|r| mem::replace(&mut *r.borrow_mut(), ndc.into()))
}
pub fn clear() {
set("");
}
pub fn push<S: Into<Ndc>>(ndc: S) -> SetGuard {
SetGuard { ndc: replace(ndc) }
}
pub fn get_raw() -> Ndc {
NDC.with(|r| r.borrow().clone())
}
pub fn get_copy() -> String {
get(|s| s.to_owned())
}
pub fn get<R, F>(f: F) -> R
where
F: FnOnce(&str) -> R,
{
NDC.with(|r| f(r.borrow().to_str()))
}
#[cfg(test)]
mod test {
mod log_ndc {
pub use super::super::*;
}
#[test]
fn set_get() {
let _g = log_ndc::push("");
log_ndc::set("aa");
assert_eq!("aa", log_ndc::get_copy());
}
#[test]
fn push() {
let _g = log_ndc::push("");
let _g1 = log_ndc::push("aa");
assert_eq!("aa", log_ndc::get_copy());
let g2 = log_ndc::push("bb");
assert_eq!("bb", log_ndc::get_copy());
drop(g2);
assert_eq!("aa", log_ndc::get_copy());
}
}