From 63a02cc06fe3530c6a0d02f8d80b6e86defd62ff Mon Sep 17 00:00:00 2001
From: Terry Hardie <terry.hardie@snowflake.com>
Date: Wed, 6 Dec 2023 15:04:01 -0800
Subject: [PATCH 1/2] Adding support for WriteAt

---
 fs.go           | 1 +
 memfs/memory.go | 8 ++++++--
 test/mock.go    | 4 ++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs.go b/fs.go
index a9efccd..cf9e57b 100644
--- a/fs.go
+++ b/fs.go
@@ -164,6 +164,7 @@ type File interface {
 	// Name returns the name of the file as presented to Open.
 	Name() string
 	io.Writer
+	io.WriterAt
 	io.Reader
 	io.ReaderAt
 	io.Seeker
diff --git a/memfs/memory.go b/memfs/memory.go
index 2e17a3c..978fed1 100644
--- a/memfs/memory.go
+++ b/memfs/memory.go
@@ -272,6 +272,10 @@ func (f *file) Seek(offset int64, whence int) (int64, error) {
 }
 
 func (f *file) Write(p []byte) (int, error) {
+	return f.WriteAt(p, f.position)
+}
+
+func (f *file) WriteAt(p []byte, off int64) (int, error) {
 	if f.isClosed {
 		return 0, os.ErrClosed
 	}
@@ -280,8 +284,8 @@ func (f *file) Write(p []byte) (int, error) {
 		return 0, errors.New("write not supported")
 	}
 
-	n, err := f.content.WriteAt(p, f.position)
-	f.position += int64(n)
+	n, err := f.content.WriteAt(p, off)
+	f.position = off + int64(n)
 
 	return n, err
 }
diff --git a/test/mock.go b/test/mock.go
index 40cbbf5..f782b26 100644
--- a/test/mock.go
+++ b/test/mock.go
@@ -115,6 +115,10 @@ func (*FileMock) ReadAt(b []byte, off int64) (int, error) {
 	return 0, nil
 }
 
+func (*FileMock) WriteAt(b []byte, off int64) (int, error) {
+	return 0, nil
+}
+
 func (*FileMock) Seek(offset int64, whence int) (int64, error) {
 	return 0, nil
 }

From 9fe7b83bdb1ebeac8d95490f7d85ddf629e8eccb Mon Sep 17 00:00:00 2001
From: Terry Hardie <65614981+sfc-gh-thardie@users.noreply.github.com>
Date: Thu, 7 Dec 2023 13:17:27 -0800
Subject: [PATCH 2/2] Update fs.go

Co-authored-by: Paulo Gomes <paulo.gomes.uk@gmail.com>
---
 fs.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs.go b/fs.go
index cf9e57b..d86f9d8 100644
--- a/fs.go
+++ b/fs.go
@@ -164,7 +164,8 @@ type File interface {
 	// Name returns the name of the file as presented to Open.
 	Name() string
 	io.Writer
-	io.WriterAt
+	// TODO: Add io.WriterAt for v6  
+	// io.WriterAt
 	io.Reader
 	io.ReaderAt
 	io.Seeker