debug: Display log in the background

src/logger/serializer.rs

@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: MPL-2.0 OR MIT OR Apache-2.0
+// Taken from slog_json:
+// https://github.com/slog-rs/json/blob/c45d09422d7114222ee5b7f6b0123de2605c7864/src/lib.rs#L39-L160
+
+use serde::ser::SerializeMap;
+use serde::serde_if_integer128;
+use slog::Key;
+use std::{fmt, io, result};
+
+use std::cell::RefCell;
+use std::fmt::Write;
+
+thread_local! {
+    static TL_BUF: RefCell<String> = RefCell::new(String::with_capacity(128))
+}
+
+/// `slog::Serializer` adapter for `serde::Serializer`
+///
+/// Newtype to wrap serde Serializer, so that `Serialize` can be implemented
+/// for it
+pub struct SerdeSerializer<S: serde::Serializer> {
+    /// Current state of map serializing: `serde::Serializer::MapState`
+    ser_map: S::SerializeMap,
+}
+
+impl<S: serde::Serializer> SerdeSerializer<S> {
+    /// Start serializing map of values
+    pub fn start(ser: S, len: Option<usize>) -> result::Result<Self, slog::Error> {
+        let ser_map = ser.serialize_map(len).map_err(|e| {
+            io::Error::new(
+                io::ErrorKind::Other,
+                format!("serde serialization error: {}", e),
+            )
+        })?;
+        Ok(SerdeSerializer { ser_map })
+    }
+
+    /// Finish serialization, and return the serializer
+    pub fn end(self) -> result::Result<S::Ok, S::Error> {
+        self.ser_map.end()
+    }
+}
+
+macro_rules! impl_m(
+    ($s:expr, $key:expr, $val:expr) => ({
+        let k_s:  &str = $key.as_ref();
+        $s.ser_map.serialize_entry(k_s, $val)
+             .map_err(|e| io::Error::new(io::ErrorKind::Other, format!("serde serialization error: {}", e)))?;
+        Ok(())
+    });
+);
+
+impl<S> slog::Serializer for SerdeSerializer<S>
+where
+    S: serde::Serializer,
+{
+    fn emit_bool(&mut self, key: Key, val: bool) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+
+    fn emit_unit(&mut self, key: Key) -> slog::Result {
+        impl_m!(self, key, &())
+    }
+
+    fn emit_char(&mut self, key: Key, val: char) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+
+    fn emit_none(&mut self, key: Key) -> slog::Result {
+        let val: Option<()> = None;
+        impl_m!(self, key, &val)
+    }
+    fn emit_u8(&mut self, key: Key, val: u8) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_i8(&mut self, key: Key, val: i8) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_u16(&mut self, key: Key, val: u16) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_i16(&mut self, key: Key, val: i16) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_usize(&mut self, key: Key, val: usize) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_isize(&mut self, key: Key, val: isize) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_u32(&mut self, key: Key, val: u32) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_i32(&mut self, key: Key, val: i32) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_f32(&mut self, key: Key, val: f32) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_u64(&mut self, key: Key, val: u64) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_i64(&mut self, key: Key, val: i64) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_f64(&mut self, key: Key, val: f64) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    serde_if_integer128! {
+        fn emit_u128(&mut self, key: Key, val: u128) -> slog::Result {
+            impl_m!(self, key, &val)
+        }
+        fn emit_i128(&mut self, key: Key, val: i128) -> slog::Result {
+            impl_m!(self, key, &val)
+        }
+    }
+    fn emit_str(&mut self, key: Key, val: &str) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_arguments(
+        &mut self,
+        key: Key,
+        val: &fmt::Arguments,
+    ) -> slog::Result {
+        TL_BUF.with(|buf| {
+            let mut buf = buf.borrow_mut();
+
+            buf.write_fmt(*val).unwrap();
+
+            let res = { || impl_m!(self, key, &*buf) }();
+            buf.clear();
+            res
+        })
+    }
+}