Lots of improvements. Most notably, removal of memory maps for searching.

Memory maps appear to degrade quite a bit in the presence of multithreading.

Also, switch to lock free data structures for synchronization. Give each
worker an input and output buffer which require no synchronization.

src/walk.rs

@@ -4,6 +4,8 @@ crate that can efficiently skip and ignore files and directories specified in
 a user's ignore patterns.
 */
 
+use std::path::PathBuf;
+
 use walkdir::{self, DirEntry, WalkDir, WalkDirIterator};
 
 use ignore::Ignore;
@@ -39,9 +41,9 @@ impl Iter {
 }
 
 impl Iterator for Iter {
-    type Item = DirEntry;
+    type Item = PathBuf;
 
-    fn next(&mut self) -> Option<DirEntry> {
+    fn next(&mut self) -> Option<PathBuf> {
         while let Some(ev) = self.it.next() {
             match ev {
                 Err(err) => {
@@ -74,7 +76,11 @@ impl Iterator for Iter {
                     if !ent.file_type().is_file() {
                         continue;
                     }
-                    return Some(ent);
+                    let mut path = ent.path();
+                    if let Ok(p) = path.strip_prefix("./") {
+                        path = p;
+                    }
+                    return Some(path.to_path_buf());
                 }
             }
         }