Merge pull request goplus#705 from luoliwoshang/os/mkdir

[wip] lib/os: patch MkdirAll

_demo/mkdirdemo/mkdir.go

@@ -0,0 +1,11 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+)
+
+func main() {
+	dirPath := filepath.Join("temp", "myapp", "data", "logs")
+	os.MkdirAll(dirPath, 0755)
+}

internal/lib/os/os.go

@@ -271,7 +271,6 @@ func Mkdir(name string, perm FileMode) error {
 */
 
 // TODO(xsw):
-// func MkdirAll(path string, perm FileMode) error
 // func NewSyscallError(syscall string, err error) error
 
 // func ReadFile(name string) ([]byte, error)

internal/lib/os/path.go

@@ -0,0 +1,55 @@
+package os
+
+import (
+	"syscall"
+)
+
+// MkdirAll creates a directory named path,
+// along with any necessary parents, and returns nil,
+// or else returns an error.
+// The permission bits perm (before umask) are used for all
+// directories that MkdirAll creates.
+// If path is already a directory, MkdirAll does nothing
+// and returns nil.
+func MkdirAll(path string, perm FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return &PathError{Op: "mkdir", Path: path, Err: syscall.ENOTDIR}
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent.
+		err = MkdirAll(fixRootDirectory(path[:j-1]), perm)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}