Implement os.RemoveAll(), test on darwin only until Readdir implemented elsewhere

Author: dkegel-fastly

src/os/file.go

@@ -60,11 +60,6 @@ func Symlink(oldname, newname string) error {
 	return ErrNotImplemented
 }
 
-// RemoveAll is a stub, it is not implemented.
-func RemoveAll(path string) error {
-	return ErrNotImplemented
-}
-
 // Name returns the name of the file with which it was opened.
 func (f *File) Name() string {
 	return f.name

src/os/path.go

@@ -59,3 +59,23 @@ func MkdirAll(path string, perm FileMode) error {
 	}
 	return nil
 }
+
+// RemoveAll removes path and any children it contains.
+// It removes everything it can but returns the first error
+// it encounters. If the path does not exist, RemoveAll
+// returns nil (no error).
+// If there is an error, it will be of type *PathError.
+func RemoveAll(path string) error {
+	return removeAll(path)
+}
+
+// endsWithDot reports whether the final component of path is ".".
+func endsWithDot(path string) bool {
+	if path == "." {
+		return true
+	}
+	if len(path) >= 2 && path[len(path)-1] == '.' && IsPathSeparator(path[len(path)-2]) {
+		return true
+	}
+	return false
+}

src/os/removeall_noat.go

@@ -0,0 +1,142 @@
+// 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.
+
+// +build !baremetal,!js
+
+package os
+
+import (
+	"io"
+	"runtime"
+	"syscall"
+)
+
+func removeAll(path string) error {
+	if path == "" {
+		// fail silently to retain compatibility with previous behavior
+		// of RemoveAll. See issue 28830.
+		return nil
+	}
+
+	// The rmdir system call permits removing "." on Plan 9,
+	// so we don't permit it to remain consistent with the
+	// "at" implementation of RemoveAll.
+	if endsWithDot(path) {
+		return &PathError{Op: "RemoveAll", Path: path, Err: syscall.EINVAL}
+	}
+
+	// Simple case: if Remove works, we're done.
+	err := Remove(path)
+	if err == nil || IsNotExist(err) {
+		return nil
+	}
+
+	// Otherwise, is this a directory we need to recurse into?
+	dir, serr := Lstat(path)
+	if serr != nil {
+		if serr, ok := serr.(*PathError); ok && (IsNotExist(serr.Err) || serr.Err == syscall.ENOTDIR) {
+			return nil
+		}
+		return serr
+	}
+	if !dir.IsDir() {
+		// Not a directory; return the error from Remove.
+		return err
+	}
+
+	// Remove contents & return first error.
+	err = nil
+	for {
+		fd, err := Open(path)
+		if err != nil {
+			if IsNotExist(err) {
+				// Already deleted by someone else.
+				return nil
+			}
+			return err
+		}
+
+		const reqSize = 1024
+		var names []string
+		var readErr error
+
+		for {
+			numErr := 0
+			names, readErr = fd.Readdirnames(reqSize)
+
+			for _, name := range names {
+				err1 := RemoveAll(path + string(PathSeparator) + name)
+				if err == nil {
+					err = err1
+				}
+				if err1 != nil {
+					numErr++
+				}
+			}
+
+			// If we can delete any entry, break to start new iteration.
+			// Otherwise, we discard current names, get next entries and try deleting them.
+			if numErr != reqSize {
+				break
+			}
+		}
+
+		// Removing files from the directory may have caused
+		// the OS to reshuffle it. Simply calling Readdirnames
+		// again may skip some entries. The only reliable way
+		// to avoid this is to close and re-open the
+		// directory. See issue 20841.
+		fd.Close()
+
+		if readErr == io.EOF {
+			break
+		}
+		// If Readdirnames returned an error, use it.
+		if err == nil {
+			err = readErr
+		}
+		if len(names) == 0 {
+			break
+		}
+
+		// We don't want to re-open unnecessarily, so if we
+		// got fewer than request names from Readdirnames, try
+		// simply removing the directory now. If that
+		// succeeds, we are done.
+		if len(names) < reqSize {
+			err1 := Remove(path)
+			if err1 == nil || IsNotExist(err1) {
+				return nil
+			}
+
+			if err != nil {
+				// We got some error removing the
+				// directory contents, and since we
+				// read fewer names than we requested
+				// there probably aren't more files to
+				// remove. Don't loop around to read
+				// the directory again. We'll probably
+				// just get the same error.
+				return err
+			}
+		}
+	}
+
+	// Remove directory.
+	err1 := Remove(path)
+	if err1 == nil || IsNotExist(err1) {
+		return nil
+	}
+	if runtime.GOOS == "windows" && IsPermission(err1) {
+		if fs, err := Stat(path); err == nil {
+			if err = Chmod(path, FileMode(0200|int(fs.Mode()))); err == nil {
+				err1 = Remove(path)
+			}
+		}
+	}
+	if err == nil {
+		err = err1
+	}
+	return err
+}