1 files changed, 51 insertions, 0 deletions
diff --git a/src/common/golang/walk.go b/src/common/golang/walk.go
new file mode 100644
index 0000000..7b73484
--- /dev/null
+++ b/src/common/golang/walk.go
@@ -0,0 +1,51 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package walk provides an utility function to walk a directory tree collecting and deduping files.
+package walk
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// Files traverses a list of paths and returns a list of all the seen files.
+func Files(paths []string) ([]string, error) {
+	var files []string
+	seen := make(map[string]bool)
+	visitFunc := func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if seen[path] {
+			return nil
+		}
+		seen[path] = true
+		switch fType := info.Mode(); {
+		case fType.IsDir():
+			// Do nothing.
+		default:
+			files = append(files, path)
+		}
+		return nil
+	}
+	for _, p := range paths {
+		err := filepath.Walk(p, visitFunc)
+		if err != nil {
+			return nil, fmt.Errorf("got error while walking %s got: %v", p, err)
+		}
+	}
+	return files, nil
+}