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

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

+// 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 (
+        "io"
+        "log"
+        "sync/atomic"
+)
+
+// FileProcessor is a basic interface for processing files provided by the
+// directory walking functions.
+type FileProcessor interface {
+        // Dir is called when a directory has been finished.
+        Dir(path string)
+
+        // SmallFile is called for processing a file which has been classed as "small".
+        SmallFile(path string, r io.ReadCloser)
+
+        // LargeFile is called for processing a file which has been classed as "large".
+        LargeFile(path string, r io.ReadCloser)
+
+        // Error is called when an error occurs on a path.
+        Error(path string, err error)
+
+        // Finished is called when the directory walk is finished.
+        Finished()
+}
+
+// BaseFileProcessor implements FileProcessor and counts the number of files of
+// each type.
+type BaseFileProcessor struct {
+        smallFiles uint64
+        largeFiles uint64
+        dirs       uint64
+}
+
+func (p *BaseFileProcessor) Dir(path string) {
+        atomic.AddUint64(&p.dirs, 1)
+}
+
+func (p *BaseFileProcessor) SmallFile(path string, r io.ReadCloser) {
+        atomic.AddUint64(&p.smallFiles, 1)
+        if r != nil {
+                r.Close()
+        }
+}
+
+func (p *BaseFileProcessor) LargeFile(path string, r io.ReadCloser) {
+        atomic.AddUint64(&p.largeFiles, 1)
+        if r != nil {
+                r.Close()
+        }
+}
+
+func (p *BaseFileProcessor) Error(path string, err error) {
+        log.Fatalf("%s:%s", path, err)
+}
+
+func (p *BaseFileProcessor) Finished() {
+}