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

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

Index: common/dirwalk/tests/tools/walkdir/fileprocessor_verify.go
diff --git a/common/dirwalk/tests/tools/walkdir/fileprocessor_verify.go b/common/dirwalk/tests/tools/walkdir/fileprocessor_verify.go
new file mode 100644
index 0000000000000000000000000000000000000000..a21833e6e626e011da0141dc0af19b20668a2901
--- /dev/null
+++ b/common/dirwalk/tests/tools/walkdir/fileprocessor_verify.go
@@ -0,0 +1,67 @@
+// 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"
+	"os"
+	"strings"
+)
+
+// VerifyFileProcessor implements FileProcessor. It verifies that things are called in the right order.
+type VerifyFileProcessor struct {
+	BaseFileProcessor
+	rootDir      string
+	finishedDirs []string
+}
+
+func (p *VerifyFileProcessor) check(path string) {
+	for _, d := range p.finishedDirs {
+		if strings.HasPrefix(path, d) {
+			log.Fatalf("Directory called before content\n    Dir: %s\nContent: %s\n", path, d)
+		}
+	}
+}
+
+func (p *VerifyFileProcessor) checkFile(path string) {
+	stat, err := os.Stat(path)
+	if err != nil {
+		log.Fatalf("Error while stating small file\n%s", path)
+	}
+	if stat.IsDir() {
+		log.Fatalf("File function called with directory!\n%s", path)
+	}
+	p.check(path)
+}
+
+func (p *VerifyFileProcessor) Dir(path string) {
+	stat, err := os.Stat(path)
+	if err != nil {
+		log.Fatalf("Error while stating directory\n%s", path)
+	}
+	if !stat.IsDir() {
+		log.Fatalf("Dir() called with non-directory!\n%s", path)
+	}
+	p.check(path)
+	p.finishedDirs = append(p.finishedDirs, path)
+	p.BaseFileProcessor.Dir(path)
+}
+
+func (p *VerifyFileProcessor) SmallFile(path string, r io.ReadCloser) {
+	p.checkFile(path)
+	p.BaseFileProcessor.SmallFile(path, r)
+}
+
+func (p *VerifyFileProcessor) LargeFile(path string, r io.ReadCloser) {
+	p.checkFile(path)
+	p.BaseFileProcessor.LargeFile(path, r)
+}
+
+func (p *VerifyFileProcessor) Finished() {
+	if strings.Compare(p.finishedDirs[len(p.finishedDirs)-1], p.rootDir) != 0 {
+		log.Fatalf("Last directory should be the root\n%s\n%s", p.finishedDirs[len(p.finishedDirs)-1], p.rootDir)
+	}
+}