From b7a07d577d59eb18a371aa57349ce913604908b7 Mon Sep 17 00:00:00 2001
From: YushiOMOTE <yushiomote@gmail.com>
Date: Sat, 13 Jul 2024 17:50:23 +0900
Subject: [PATCH 1/2] Support custom formatter

---
 src/lib.rs    |  2 +-
 src/logger.rs | 79 +++++++++++++++++++++++++++++++++++++--------------
 2 files changed, 59 insertions(+), 22 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 63de775..4193275 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,5 +8,5 @@ mod logger;
 /// The module for the serial port driver.
 mod serial;
 
-pub use crate::logger::{builder, init, init_with_filter, Builder};
+pub use crate::logger::{builder, init, init_with_filter, Builder, Formatter};
 pub use crate::serial::Serial;
diff --git a/src/logger.rs b/src/logger.rs
index cf8ee6a..0b33a99 100644
--- a/src/logger.rs
+++ b/src/logger.rs
@@ -1,13 +1,44 @@
 use crate::serial::Serial;
-use core::{fmt::write, format_args};
+use core::{fmt::Write, writeln};
 use log::*;
 use spin::Mutex;
 
 const COM1_PORT: u16 = 0x3f8;
 
-static LOGGER: Logger = Logger(Mutex::new(COM1_PORT));
+static LOGGER: Logger = Logger::new(COM1_PORT);
 
-struct Logger(Mutex<u16>);
+/// Formatter that converts log records into desirable text format.
+pub type Formatter = fn(&mut dyn Write, &Record) -> Result<(), core::fmt::Error>;
+
+struct Inner {
+    base: u16,
+    formatter: Formatter,
+}
+
+struct Logger {
+    inner: Mutex<Inner>,
+}
+
+impl Logger {
+    const fn new(base: u16) -> Self {
+        Logger {
+            inner: Mutex::new(Inner {
+                base,
+                formatter: default_formatter,
+            }),
+        }
+    }
+
+    fn set_base(&self, new_base: u16) {
+        let mut inner = self.inner.lock();
+        inner.base = new_base;
+    }
+
+    fn set_formatter(&self, new_formatter: Formatter) {
+        let mut inner = self.inner.lock();
+        inner.formatter = new_formatter;
+    }
+}
 
 impl log::Log for Logger {
     fn enabled(&self, _m: &Metadata) -> bool {
@@ -15,28 +46,25 @@ impl log::Log for Logger {
     }
 
     fn log(&self, record: &Record) {
-        let port = self.0.lock();
-        let mut serial = Serial::new(*port);
-
-        let _ = write(
-            &mut serial,
-            format_args!(
-                "{:>8}: {} ({}, {}:{})\n",
-                record.level(),
-                record.args(),
-                record.target(),
-                record.file().unwrap_or("<unknown>"),
-                record.line().unwrap_or(0),
-            ),
-        );
+        let inner = self.inner.lock();
+        let mut serial = Serial::new(inner.base);
+
+        let _ = (inner.formatter)(&mut serial, record);
     }
 
     fn flush(&self) {}
 }
 
-fn set_logger_base(base: u16) {
-    let mut data = LOGGER.0.lock();
-    *data = base;
+fn default_formatter(buffer: &mut dyn Write, record: &Record) -> Result<(), core::fmt::Error> {
+    writeln!(
+        buffer,
+        "{:>8}: {} ({}, {}:{})\n",
+        record.level(),
+        record.args(),
+        record.target(),
+        record.file().unwrap_or("<unknown>"),
+        record.line().unwrap_or(0)
+    )
 }
 
 /// The builder for a serial port logger.
@@ -45,6 +73,7 @@ fn set_logger_base(base: u16) {
 pub struct Builder {
     base: u16,
     filter: LevelFilter,
+    formatter: Formatter,
 }
 
 impl Builder {
@@ -53,6 +82,7 @@ impl Builder {
         Self {
             base: COM1_PORT,
             filter: LevelFilter::Info,
+            formatter: default_formatter,
         }
     }
 
@@ -68,13 +98,20 @@ impl Builder {
         self
     }
 
+    /// Set formatter.
+    pub fn formatter(mut self, formatter: Formatter) -> Self {
+        self.formatter = formatter;
+        self
+    }
+
     /// Setup a logger based on the configuration.
     pub fn setup(self) {
         // Initialize serial port
         Serial::new(self.base).init();
 
         // Update base address of logger
-        set_logger_base(self.base);
+        LOGGER.set_base(self.base);
+        LOGGER.set_formatter(self.formatter);
 
         set_logger(&LOGGER).unwrap();
         set_max_level(self.filter);

From e949ed2967b78bd6470833e858cc6da289a933b7 Mon Sep 17 00:00:00 2001
From: YushiOMOTE <yushiomote@gmail.com>
Date: Sat, 13 Jul 2024 17:50:47 +0900
Subject: [PATCH 2/2] Add formatter to documentation

---
 README.md     | 1 +
 src/logger.rs | 1 +
 src/serial.rs | 3 ++-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 2a58615..03ce3e9 100644
--- a/README.md
+++ b/README.md
@@ -29,6 +29,7 @@ fn main() {
     com_logger::builder()
         .base(0x2f8)                  // Use COM2 port
         .filter(LevelFilter::Debug)   // Print debug log
+        .formatter(|buf, record| writeln!(buf, "{}", record.args())) // Define own format
         .setup();
 
     debug!("Hello");
diff --git a/src/logger.rs b/src/logger.rs
index 0b33a99..a5344fc 100644
--- a/src/logger.rs
+++ b/src/logger.rs
@@ -129,6 +129,7 @@ impl Builder {
 ///    com_logger::builder()
 ///        .base(0x2f8)                  // Use COM2 port
 ///        .filter(LevelFilter::Debug)   // Print debug log
+///        .formatter(|buf, record| writeln!(buf, "{}", record.args())) // Define own format
 ///        .setup();
 ///
 ///    debug!("Hello");
diff --git a/src/serial.rs b/src/serial.rs
index 7a090be..6446060 100644
--- a/src/serial.rs
+++ b/src/serial.rs
@@ -5,6 +5,7 @@ use uart_16550::SerialPort;
 ///
 /// ```rust,no_run
 /// use com_logger::Serial;
+/// use core::fmt::Write;
 ///
 /// fn main() {
 ///    // Setup COM1 serial port.
@@ -15,7 +16,7 @@ use uart_16550::SerialPort;
 ///    s.write(b'P');
 ///
 ///    // Write the string to the serial port.
-///    core::fmt::write(&mut s, format_args!("Hello {}", 0xdead));
+///    writeln!(&mut s, "Hello {}", 0xdead);
 /// }
 /// ```
 pub struct Serial(SerialPort);