logging: Move all facilities to one file

src/logging.rs

@@ -0,0 +1,43 @@
+/*! Logging library */
+
+use std::error::Error;
+
+/// Sugar for logging errors in results
+pub trait Warn {
+    type Value;
+    fn ok_warn(self, msg: &str) -> Option<Self::Value>;
+}
+
+impl<T, E: Error> Warn for Result<T, E> {
+    type Value = T;
+    fn ok_warn(self, msg: &str) -> Option<T> {
+        self.map_err(|e| {
+            eprintln!("{}: {}", msg, e);
+            e
+        }).ok()
+    }
+}
+
+pub trait WarningHandler {
+    /// Handle a warning
+    fn handle(&mut self, warning: &str);
+}
+
+/// Prints warnings to stderr
+pub struct PrintWarnings;
+
+impl WarningHandler for PrintWarnings {
+    fn handle(&mut self, warning: &str) {
+        eprintln!("{}", warning);
+    }
+}
+
+/// Warning handler that will panic at any warning.
+/// Don't use except in tests
+pub struct PanicWarn;
+
+impl WarningHandler for PanicWarn {
+    fn handle(&mut self, warning: &str) {
+        panic!("{}", warning);
+    }
+}