1 files changed, 103 insertions, 0 deletions
diff --git a/libgo/go/cmd/go/internal/dirhash/hash.go b/libgo/go/cmd/go/internal/dirhash/hash.go
new file mode 100644
index 00000000000..61d8face567
--- /dev/null
+++ b/libgo/go/cmd/go/internal/dirhash/hash.go
@@ -0,0 +1,103 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package dirhash defines hashes over directory trees.
+package dirhash
+
+import (
+	"archive/zip"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+var DefaultHash = Hash1
+
+type Hash func(files []string, open func(string) (io.ReadCloser, error)) (string, error)
+
+func Hash1(files []string, open func(string) (io.ReadCloser, error)) (string, error) {
+	h := sha256.New()
+	files = append([]string(nil), files...)
+	sort.Strings(files)
+	for _, file := range files {
+		if strings.Contains(file, "\n") {
+			return "", errors.New("filenames with newlines are not supported")
+		}
+		r, err := open(file)
+		if err != nil {
+			return "", err
+		}
+		hf := sha256.New()
+		_, err = io.Copy(hf, r)
+		r.Close()
+		if err != nil {
+			return "", err
+		}
+		fmt.Fprintf(h, "%x  %s\n", hf.Sum(nil), file)
+	}
+	return "h1:" + base64.StdEncoding.EncodeToString(h.Sum(nil)), nil
+}
+
+func HashDir(dir, prefix string, hash Hash) (string, error) {
+	files, err := DirFiles(dir, prefix)
+	if err != nil {
+		return "", err
+	}
+	osOpen := func(name string) (io.ReadCloser, error) {
+		return os.Open(filepath.Join(dir, strings.TrimPrefix(name, prefix)))
+	}
+	return hash(files, osOpen)
+}
+
+func DirFiles(dir, prefix string) ([]string, error) {
+	var files []string
+	dir = filepath.Clean(dir)
+	err := filepath.Walk(dir, func(file string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+		rel := file
+		if dir != "." {
+			rel = file[len(dir)+1:]
+		}
+		f := filepath.Join(prefix, rel)
+		files = append(files, filepath.ToSlash(f))
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return files, nil
+}
+
+func HashZip(zipfile string, hash Hash) (string, error) {
+	z, err := zip.OpenReader(zipfile)
+	if err != nil {
+		return "", err
+	}
+	defer z.Close()
+	var files []string
+	zfiles := make(map[string]*zip.File)
+	for _, file := range z.File {
+		files = append(files, file.Name)
+		zfiles[file.Name] = file
+	}
+	zipOpen := func(name string) (io.ReadCloser, error) {
+		f := zfiles[name]
+		if f == nil {
+			return nil, fmt.Errorf("file %q not found in zip", name) // should never happen
+		}
+		return f.Open()
+	}
+	return hash(files, zipOpen)
+}