luci-go/common/dirwalk: Code for walking a directory tree efficiently

common/dirwalk/tests/tools/walkdir/walkers_print.go

Index: common/dirwalk/tests/tools/walkdir/walkers_print.go
diff --git a/common/dirwalk/tests/tools/walkdir/walkers_print.go b/common/dirwalk/tests/tools/walkdir/walkers_print.go
new file mode 100644
index 0000000000000000000000000000000000000000..dd93eedd11f59945e54094c9129e69f18967a6d3
--- /dev/null
+++ b/common/dirwalk/tests/tools/walkdir/walkers_print.go
@@ -0,0 +1,30 @@
+// Copyright 2016 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	"io"
+)
+
+// PrintWalker implements Walker. It prints the filename of each found file.
+type PrintWalker struct {
+	BaseWalker
+	obuf io.Writer
+}
+
+func (p *PrintWalker) PrintFile(filename string) {
+	fmt.Fprintln(p.obuf, filename)
+}
+
+func (p *PrintWalker) SmallFile(filename string, alldata []byte) {
+	p.BaseWalker.SmallFile(filename, alldata)
+	p.PrintFile(filename)
+}
+
+func (p *PrintWalker) LargeFile(filename string) {
+	p.BaseWalker.LargeFile(filename)
+	p.PrintFile(filename)
+}