1 files changed, 90 insertions, 0 deletions
diff --git a/crates/printer/src/counter.rs b/crates/printer/src/counter.rs
new file mode 100644
index 00000000..c2faac83
--- /dev/null
+++ b/crates/printer/src/counter.rs
@@ -0,0 +1,90 @@
+use std::io::{self, Write};
+
+use termcolor::{ColorSpec, WriteColor};
+
+/// A writer that counts the number of bytes that have been successfully
+/// written.
+#[derive(Clone, Debug)]
+pub struct CounterWriter<W> {
+    wtr: W,
+    count: u64,
+    total_count: u64,
+}
+
+impl<W: Write> CounterWriter<W> {
+    pub fn new(wtr: W) -> CounterWriter<W> {
+        CounterWriter { wtr: wtr, count: 0, total_count: 0 }
+    }
+}
+
+impl<W> CounterWriter<W> {
+    /// Returns the total number of bytes written since construction or the
+    /// last time `reset` was called.
+    pub fn count(&self) -> u64 {
+        self.count
+    }
+
+    /// Returns the total number of bytes written since construction.
+    pub fn total_count(&self) -> u64 {
+        self.total_count + self.count
+    }
+
+    /// Resets the number of bytes written to `0`.
+    pub fn reset_count(&mut self) {
+        self.total_count += self.count;
+        self.count = 0;
+    }
+
+    /// Clear resets all counting related state for this writer.
+    ///
+    /// After this call, the total count of bytes written to the underlying
+    /// writer is erased and reset.
+    #[allow(dead_code)]
+    pub fn clear(&mut self) {
+        self.count = 0;
+        self.total_count = 0;
+    }
+
+    #[allow(dead_code)]
+    pub fn get_ref(&self) -> &W {
+        &self.wtr
+    }
+
+    pub fn get_mut(&mut self) -> &mut W {
+        &mut self.wtr
+    }
+
+    pub fn into_inner(self) -> W {
+        self.wtr
+    }
+}
+
+impl<W: Write> Write for CounterWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
+        let n = self.wtr.write(buf)?;
+        self.count += n as u64;
+        Ok(n)
+    }
+
+    fn flush(&mut self) -> Result<(), io::Error> {
+        self.wtr.flush()
+    }
+}
+
+impl<W: WriteColor> WriteColor for CounterWriter<W> {
+    fn supports_color(&self) -> bool {
+        self.wtr.supports_color()
+    }
+
+    fn set_color(&mut self, spec: &ColorSpec) -> io::Result<()> {
+        self.wtr.set_color(spec)
+    }
+
+    fn reset(&mut self) -> io::Result<()> {
+        self.wtr.reset()
+    }
+
+    fn is_synchronous(&self) -> bool {
+        self.wtr.is_synchronous()
+    }
+}