Implementing core functionality.

Initially experimenting with crossbeam to manage synchronization.

src/printer.rs

@@ -0,0 +1,50 @@
+use std::io;
+use std::path::Path;
+
+use grep::Match;
+
+macro_rules! wln {
+    ($($tt:tt)*) => {
+        let _ = writeln!($($tt)*);
+    }
+}
+
+pub struct Printer<W> {
+    wtr: W,
+}
+
+impl<W: io::Write> Printer<W> {
+    pub fn new(wtr: W) -> Printer<W> {
+        Printer {
+            wtr: wtr,
+        }
+    }
+
+    pub fn into_inner(self) -> W {
+        self.wtr
+    }
+
+    pub fn path<P: AsRef<Path>>(&mut self, path: P) {
+        wln!(&mut self.wtr, "{}", path.as_ref().display());
+    }
+
+    pub fn count(&mut self, count: u64) {
+        wln!(&mut self.wtr, "{}", count);
+    }
+
+    pub fn matched<P: AsRef<Path>>(
+        &mut self,
+        path: P,
+        buf: &[u8],
+        m: &Match,
+    ) {
+        let _ = self.wtr.write(path.as_ref().to_string_lossy().as_bytes());
+        let _ = self.wtr.write(b":");
+        let _ = self.wtr.write(&buf[m.start()..m.end()]);
+        let _ = self.wtr.write(b"\n");
+    }
+
+    pub fn binary_matched<P: AsRef<Path>>(&mut self, path: P) {
+        wln!(&mut self.wtr, "binary file {} matches", path.as_ref().display());
+    }
+}