Flat directory/module structure

src/warnings.rs

@@ -0,0 +1,41 @@
+use std::fmt;
+
+use crate::format::format_duration;
+use crate::internal::MIN_EXECUTION_TIME;
+use crate::units::Second;
+
+/// A list of all possible warnings
+pub enum Warnings {
+    FastExecutionTime,
+    NonZeroExitCode,
+    SlowInitialRun(Second),
+    OutliersDetected,
+}
+
+impl fmt::Display for Warnings {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Warnings::FastExecutionTime => write!(
+                f,
+                "Command took less than {:.0} ms to complete. Results might be inaccurate.",
+                MIN_EXECUTION_TIME * 1e3
+            ),
+            Warnings::NonZeroExitCode => write!(f, "Ignoring non-zero exit code."),
+            Warnings::SlowInitialRun(t_first) => write!(
+                f,
+                "The first benchmarking run for this command was significantly slower than the \
+                 rest ({}). This could be caused by (filesystem) caches that were not filled until \
+                 after the first run. You should consider using the '--warmup' option to fill \
+                 those caches before the actual benchmark. Alternatively, use the '--prepare' \
+                 option to clear the caches before each timing run.",
+                format_duration(t_first, None)
+            ),
+            Warnings::OutliersDetected => write!(
+                f,
+                "Statistical outliers were detected. Consider re-running this benchmark on a quiet \
+                 PC without any interferences from other programs. It might help to use the \
+                 '--warmup' or '--prepare' options."
+            ),
+        }
+    }
+}