Tidy up handling of stderr+colors

Author: borntyping

Cargo.toml

@@ -27,6 +27,10 @@ windows-sys = { version = "^0.48.0", features = ["Win32_System_Console", "Win32_
 name = "colors"
 required-features = ["colors"]
 
+[[example]]
+name = "stderr"
+required-features = ["colors", "stderr"]
+
 [[example]]
 name = "threads"
 required-features = ["threads"]

README.md

@@ -104,22 +104,13 @@ You might want to wrap this logger to do your own processing before handing even
 of calling `init()` which calls `log::set_max_level` and `log::set_boxed_logger`, you can call those functions directly
 giving you the chance to wrap or adjust the logger. See [wrap.rs](examples/wrap.rs) for a more detailed example.
 
-The call to `set_up_color_terminal()` is currently only needed on Windows when the `colored` feature is enabled. If
-you're not on Windows and not using the `colored` feature, it will do nothing. 
+### Console setup
 
-```rust
-use simple_logger::{SimpleLogger, set_up_color_terminal};
-
-fn main() {
-    set_up_color_terminal();
+The `SimpleLogger.init()` function attempts to configure colours support as best it can in various situations:
 
-    let logger = SimpleLogger::new();
-    let max_level = logger.max_level();
-
-    log::set_max_level(max_level);
-    log::set_boxed_logger(Box::new(logger)).unwrap();
-}
-```
+- On Windows, it will enable colour output. _See `set_up_windows_color_terminal()`._
+- When using the `colors` *and* `stderr` features, it will instruct the `colored` library to display colors if STDERR
+  is a terminal (instead of checking if STDOUT is a terminal). _See `use_stderr_for_colors()`._
 
 Licence
 -------

examples/stderr.rs

@@ -0,0 +1,7 @@
+use simple_logger::SimpleLogger;
+
+fn main() {
+    SimpleLogger::new().with_colors(true).init().unwrap();
+
+    log::warn!("This is an example message.");
+}

examples/wrap.rs

@@ -1,5 +1,5 @@
 use log::{Log, Metadata, Record};
-use simple_logger::{set_up_color_terminal, SimpleLogger};
+use simple_logger::SimpleLogger;
 
 struct WrapperLogger {
     simple_logger: SimpleLogger,
@@ -20,11 +20,11 @@ impl Log for WrapperLogger {
 }
 
 fn main() {
-    set_up_color_terminal();
-
     let simple_logger = SimpleLogger::new();
     log::set_max_level(simple_logger.max_level());
 
     let wrapper_logger = WrapperLogger { simple_logger };
     log::set_boxed_logger(Box::new(wrapper_logger)).unwrap();
+
+    log::warn!("This is an example message.");
 }

src/lib.rs

@@ -348,8 +348,11 @@ impl SimpleLogger {
     /// 'Init' the actual logger and instantiate it,
     /// this method MUST be called in order for the logger to be effective.
     pub fn init(self) -> Result<(), SetLoggerError> {
-        // Setup colors if needed. The implementation if feature dependent.
-        set_up_color_terminal();
+        #[cfg(all(windows, feature = "colored"))]
+        set_up_windows_color_terminal();
+
+        #[cfg(all(feature = "colored", feature = "stderr"))]
+        use_stderr_for_colors();
 
         log::set_max_level(self.max_level());
         log::set_boxed_logger(Box::new(self))
@@ -481,11 +484,12 @@ impl Log for SimpleLogger {
     fn flush(&self) {}
 }
 
-/// Configure the console to display colours - Windows + colored
+/// Configure the console to display colours.
 ///
-/// This is only needed on Windows when using the 'colored' feature.
+/// This is only needed on Windows when using the 'colors' feature.
+/// It doesn't currently handle combining the 'colors' and 'stderr' features.
 #[cfg(all(windows, feature = "colors"))]
-pub fn set_up_color_terminal() {
+pub fn set_up_windows_color_terminal() {
     use std::io::{stdout, IsTerminal};
 
     if stdout().is_terminal() {
@@ -513,32 +517,15 @@ pub fn set_up_color_terminal() {
     }
 }
 
-/// Configure the console to display colours - Windows + !colored
-///
-/// This method does nothing if running on Windows with the colored feature disabled.
-#[cfg(all(windows, not(feature = "colors")))]
-pub fn set_up_color_terminal() {}
+/// The colored crate will disable colors when STDOUT is not a terminal. This method overrides this
+/// behaviour to check the status of STDERR instead.
+#[cfg(all(feature = "colored", feature = "stderr"))]
+fn use_stderr_for_colors() {
+    use std::io::{stderr, IsTerminal};
 
-/// Configure the console to display colours - !Windows + stderr + colors
-///
-/// The colored crate will disable colors when stdout is not a terminal. This method overrides this
-/// behaviour to check the status of stderr instead.
-#[cfg(all(not(windows), feature = "stderr"))]
-pub fn set_up_color_terminal() {
-    #[cfg(feature = "colors")]
-    {
-        use std::io::{stderr, IsTerminal};
-        colored::control::set_override(stderr().is_terminal());
-    }
+    colored::control::set_override(stderr().is_terminal());
 }
 
-/// Configure the console to display colours - !Windows + !stderr
-///
-/// This method does nothing if not running on Windows with the colored feature and outputting on
-/// stdout.
-#[cfg(all(not(windows), not(feature = "stderr")))]
-pub fn set_up_color_terminal() {}
-
 /// Initialise the logger with its default configuration.
 ///
 /// Log messages will not be filtered.