From cc012235351fd466fd02ee1092ecb656d583f651 Mon Sep 17 00:00:00 2001
From: Janne Hellsten <jjhellst@gmail.com>
Date: Tue, 4 Apr 2023 18:19:16 +0300
Subject: [PATCH] fs: Implement PartialUploads feature flag

Implement a Partialuploads feature flag to mark backends for which
uploads are not atomic.

This is set for the following backends

- local
- ftp
- sftp

See #3770
---
 backend/ftp/ftp.go     | 1 +
 backend/local/local.go | 1 +
 backend/sftp/sftp.go   | 1 +
 fs/features.go         | 1 +
 4 files changed, 4 insertions(+)

diff --git a/backend/ftp/ftp.go b/backend/ftp/ftp.go
index 7aa9935c5..7db6437e3 100644
--- a/backend/ftp/ftp.go
+++ b/backend/ftp/ftp.go
@@ -580,6 +580,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (ff fs.Fs
 	}
 	f.features = (&fs.Features{
 		CanHaveEmptyDirectories: true,
+		PartialUploads:          true,
 	}).Fill(ctx, f)
 	// set the pool drainer timer going
 	if f.opt.IdleTimeout > 0 {
diff --git a/backend/local/local.go b/backend/local/local.go
index 4acb1b788..a83a3c455 100644
--- a/backend/local/local.go
+++ b/backend/local/local.go
@@ -303,6 +303,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		WriteMetadata:           true,
 		UserMetadata:            xattrSupported, // can only R/W general purpose metadata if xattrs are supported
 		FilterAware:             true,
+		PartialUploads:          true,
 	}).Fill(ctx, f)
 	if opt.FollowSymlinks {
 		f.lstat = os.Stat
diff --git a/backend/sftp/sftp.go b/backend/sftp/sftp.go
index 6338534bf..6127a2333 100644
--- a/backend/sftp/sftp.go
+++ b/backend/sftp/sftp.go
@@ -994,6 +994,7 @@ func NewFsWithConnection(ctx context.Context, f *Fs, name string, root string, m
 	f.features = (&fs.Features{
 		CanHaveEmptyDirectories: true,
 		SlowHash:                true,
+		PartialUploads:          true,
 	}).Fill(ctx, f)
 	// Make a connection and pool it to return errors early
 	c, err := f.getSftpConnection(ctx)
diff --git a/fs/features.go b/fs/features.go
index 8a85c0226..5820b1178 100644
--- a/fs/features.go
+++ b/fs/features.go
@@ -30,6 +30,7 @@ type Features struct {
 	WriteMetadata           bool // can write metadata to objects
 	UserMetadata            bool // can read/write general purpose metadata
 	FilterAware             bool // can make use of filters if provided for listing
+	PartialUploads          bool // uploaded file can appear incomplete on the fs while it's being uploaded
 
 	// Purge all files in the directory specified
 	//