refactor symWalk() into pkg/sympath (#3199)

* refactor symWalk() into pkg/sympath

* add Go copyright

* remove dead code

pkg/chartutil/load.go

@@ -32,6 +32,7 @@ import (
 
 	"k8s.io/helm/pkg/ignore"
 	"k8s.io/helm/pkg/proto/hapi/chart"
+	"k8s.io/helm/pkg/sympath"
 )
 
 // Load takes a string name, tries to resolve it to a file or directory, and then loads it.
@@ -279,44 +280,9 @@ func LoadDir(dir string) (*chart.Chart, error) {
 		files = append(files, &BufferedFile{Name: n, Data: data})
 		return nil
 	}
-	if err = filepath.Walk(topdir, symWalk(topdir, "", walk)); err != nil {
+	if err = sympath.Walk(topdir, walk); err != nil {
 		return c, err
 	}
 
 	return LoadFiles(files)
 }
-
-// symWalk walks topdir with optional symbolic link dir, symdir. The symdir will
-// be used as the path name sent to walkFn.
-func symWalk(topdir, symdir string, walkFn filepath.WalkFunc) filepath.WalkFunc {
-	return func(name string, fi os.FileInfo, err error) error {
-		// Recover the symbolic path instead of the real path.
-		if symdir != "" {
-			relative, err := filepath.Rel(topdir, name)
-			if err != nil {
-				return err
-			}
-			name = filepath.Join(symdir, relative)
-		}
-
-		// Recursively walk symlinked directories.
-		if isSymlink(fi) {
-			resolved, err := filepath.EvalSymlinks(name)
-			if err != nil {
-				return fmt.Errorf("error evaluating symlink %s: %s", name, err)
-			}
-			if fi, err = os.Lstat(resolved); err != nil {
-				return err
-			}
-			if fi.IsDir() {
-				return filepath.Walk(resolved, symWalk(resolved, name, walkFn))
-			}
-		}
-
-		return walkFn(name, fi, err)
-	}
-}
-
-func isSymlink(fi os.FileInfo) bool {
-	return fi.Mode()&os.ModeSymlink != 0
-}

pkg/sympath/walk.go

+/*
+Copyright (c) for portions of walk.go are held by The Go Authors, 2009 and are provided under
+the BSD license.
+
+https://github.com/golang/go/blob/master/LICENSE
+
+Copyright 2017 The Kubernetes 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 sympath
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+)
+
+// Walk walks the file tree rooted at root, calling walkFn for each file or directory
+// in the tree, including root. All errors that arise visiting files and directories
+// are filtered by walkFn. The files are walked in lexical order, which makes the
+// output deterministic but means that for very large directories Walk can be
+// inefficient. Walk follows symbolic links.
+func Walk(root string, walkFn filepath.WalkFunc) error {
+	info, err := os.Lstat(root)
+	if err != nil {
+		err = walkFn(root, nil, err)
+	} else {
+		err = symwalk(root, info, walkFn)
+	}
+	if err == filepath.SkipDir {
+		return nil
+	}
+	return err
+}
+
+// readDirNames reads the directory named by dirname and returns
+// a sorted list of directory entries.
+func readDirNames(dirname string) ([]string, error) {
+	f, err := os.Open(dirname)
+	if err != nil {
+		return nil, err
+	}
+	names, err := f.Readdirnames(-1)
+	f.Close()
+	if err != nil {
+		return nil, err
+	}
+	sort.Strings(names)
+	return names, nil
+}
+
+// symwalk recursively descends path, calling walkFn.
+func symwalk(path string, info os.FileInfo, walkFn filepath.WalkFunc) error {
+	// Recursively walk symlinked directories.
+	if IsSymlink(info) {
+		resolved, err := filepath.EvalSymlinks(path)
+		if err != nil {
+			return fmt.Errorf("error evaluating symlink %s: %s", path, err)
+		}
+		if info, err = os.Lstat(resolved); err != nil {
+			return err
+		}
+		if err := symwalk(resolved, info, walkFn); err != nil && err != filepath.SkipDir {
+			return err
+		}
+	}
+
+	if err := walkFn(path, info, nil); err != nil {
+		return err
+	}
+
+	if !info.IsDir() {
+		return nil
+	}
+
+	names, err := readDirNames(path)
+	if err != nil {
+		return walkFn(path, info, err)
+	}
+
+	for _, name := range names {
+		filename := filepath.Join(path, name)
+		fileInfo, err := os.Lstat(filename)
+		if err != nil {
+			if err := walkFn(filename, fileInfo, err); err != nil && err != filepath.SkipDir {
+				return err
+			}
+		} else {
+			err = symwalk(filename, fileInfo, walkFn)
+			if err != nil {
+				if (!fileInfo.IsDir() && !IsSymlink(fileInfo)) || err != filepath.SkipDir {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// IsSymlink is used to determine if the fileinfo is a symbolic link.
+func IsSymlink(fi os.FileInfo) bool {
+	return fi.Mode()&os.ModeSymlink != 0
+}

pkg/sympath/walk_test.go

+/*
+Copyright (c) for portions of walk_test.go are held by The Go Authors, 2009 and are provided under
+the BSD license.
+
+https://github.com/golang/go/blob/master/LICENSE
+
+Copyright 2017 The Kubernetes 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 sympath
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+type Node struct {
+	name    string
+	entries []*Node // nil if the entry is a file
+	mark    int
+}
+
+var tree = &Node{
+	"testdata",
+	[]*Node{
+		{"a", nil, 0},
+		{"b", []*Node{}, 0},
+		{"c", nil, 0},
+		{
+			"d",
+			[]*Node{
+				{"x", nil, 0},
+				{"y", []*Node{}, 0},
+				{
+					"z",
+					[]*Node{
+						{"u", nil, 0},
+						{"v", nil, 0},
+						{"w", nil, 0},
+					},
+					0,
+				},
+			},
+			0,
+		},
+	},
+	0,
+}
+
+func walkTree(n *Node, path string, f func(path string, n *Node)) {
+	f(path, n)
+	for _, e := range n.entries {
+		walkTree(e, filepath.Join(path, e.name), f)
+	}
+}
+
+func makeTree(t *testing.T) {
+	walkTree(tree, tree.name, func(path string, n *Node) {
+		if n.entries == nil {
+			fd, err := os.Create(path)
+			if err != nil {
+				t.Errorf("makeTree: %v", err)
+				return
+			}
+			fd.Close()
+		} else {
+			os.Mkdir(path, 0770)
+		}
+	})
+}
+
+func checkMarks(t *testing.T, report bool) {
+	walkTree(tree, tree.name, func(path string, n *Node) {
+		if n.mark != 1 && report {
+			t.Errorf("node %s mark = %d; expected 1", path, n.mark)
+		}
+		n.mark = 0
+	})
+}
+
+// Assumes that each node name is unique. Good enough for a test.
+// If clear is true, any incoming error is cleared before return. The errors
+// are always accumulated, though.
+func mark(info os.FileInfo, err error, errors *[]error, clear bool) error {
+	if err != nil {
+		*errors = append(*errors, err)
+		if clear {
+			return nil
+		}
+		return err
+	}
+	name := info.Name()
+	walkTree(tree, tree.name, func(path string, n *Node) {
+		if n.name == name {
+			n.mark++
+		}
+	})
+	return nil
+}
+
+func TestWalk(t *testing.T) {
+	makeTree(t)
+	errors := make([]error, 0, 10)
+	clear := true
+	markFn := func(path string, info os.FileInfo, err error) error {
+		return mark(info, err, &errors, clear)
+	}
+	// Expect no errors.
+	err := Walk(tree.name, markFn)
+	if err != nil {
+		t.Fatalf("no error expected, found: %s", err)
+	}
+	if len(errors) != 0 {
+		t.Fatalf("unexpected errors: %s", errors)
+	}
+	checkMarks(t, true)
+
+	// cleanup
+	if err := os.RemoveAll(tree.name); err != nil {
+		t.Errorf("removeTree: %v", err)
+	}
+}