Add OpenWritable to fs interfaces

3 files changed, 16 insertions, 3 deletions

diff --git a/fs/fs.go b/fs/fs.go
index b06ded8..d6d0618 100644
--- a/fs/fs.go
+++ b/fs/fs.go
@@ -23,7 +23,8 @@ type File interface {
 
 type RegularFile interface {
 	File
-	Open() (io.ReadWriteCloser, error)
+	Open() (io.ReadCloser, error)
+	OpenWritable() (io.WriteCloser, error)
 }
 
 type Dir interface {
diff --git a/fs/memory.go b/fs/memory.go
index 221ff36..2bc11dc 100644
--- a/fs/memory.go
+++ b/fs/memory.go
@@ -40,7 +40,11 @@ type memfsFile struct {
 
 func (memfsFile) Type() FileType { return FFile }
 
-func (f memfsFile) Open() (io.ReadWriteCloser, error) {
+func (f memfsFile) Open() (io.ReadCloser, error) {
+	return f, nil
+}
+
+func (f memfsFile) OpenWritable() (io.WriteCloser, error) {
 	return f, nil
 }
 
diff --git a/fs/os.go b/fs/os.go
index f41d111..166cf92 100644
--- a/fs/os.go
+++ b/fs/os.go
@@ -58,7 +58,7 @@ func (f osFile) Delete() error {
 	return os.RemoveAll(f.fullpath)
 }
 
-func (f osFile) Open() (io.ReadWriteCloser, error) {
+func (f osFile) Open() (io.ReadCloser, error) {
 	fh, err := os.Open(f.fullpath)
 	if err != nil {
 		return nil, err
@@ -66,6 +66,14 @@ func (f osFile) Open() (io.ReadWriteCloser, error) {
 	return fh, nil
 }
 
+func (f osFile) OpenWritable() (io.WriteCloser, error) {
+	fh, err := os.Create(f.fullpath)
+	if err != nil {
+		return nil, err
+	}
+	return fh, nil
+}
+
 func (f osFile) Readdir() (list []File, err error) {
 	fh, err := os.Open(f.fullpath)
 	if err != nil {