1 files changed, 52 insertions, 0 deletions
diff --git a/third_party/rust/bindgen/time.rs b/third_party/rust/bindgen/time.rs
new file mode 100644
index 0000000000..c13a640c46
--- /dev/null
+++ b/third_party/rust/bindgen/time.rs
@@ -0,0 +1,52 @@
+use std::io::{self, Write};
+use std::time::{Duration, Instant};
+
+/// RAII timer to measure how long phases take.
+#[derive(Debug)]
+pub struct Timer<'a> {
+    output: bool,
+    name: &'a str,
+    start: Instant,
+}
+
+impl<'a> Timer<'a> {
+    /// Creates a Timer with the given name, and starts it. By default,
+    /// will print to stderr when it is `drop`'d
+    pub fn new(name: &'a str) -> Self {
+        Timer {
+            output: true,
+            name,
+            start: Instant::now(),
+        }
+    }
+
+    /// Sets whether or not the Timer will print a message
+    /// when it is dropped.
+    pub fn with_output(mut self, output: bool) -> Self {
+        self.output = output;
+        self
+    }
+
+    /// Returns the time elapsed since the timer's creation
+    pub fn elapsed(&self) -> Duration {
+        Instant::now() - self.start
+    }
+
+    fn print_elapsed(&mut self) {
+        if self.output {
+            let elapsed = self.elapsed();
+            let time = (elapsed.as_secs() as f64) * 1e3 +
+                (elapsed.subsec_nanos() as f64) / 1e6;
+            let stderr = io::stderr();
+            // Arbitrary output format, subject to change.
+            writeln!(stderr.lock(), "  time: {:>9.3} ms.\t{}", time, self.name)
+                .expect("timer write should not fail");
+        }
+    }
+}
+
+impl<'a> Drop for Timer<'a> {
+    fn drop(&mut self) {
+        self.print_elapsed();
+    }
+}