union: Implement multiple writable remotes

backend/union/policy/all.go

@@ -0,0 +1,44 @@
+package policy
+
+import (
+	"context"
+
+	"github.com/rclone/rclone/backend/union/upstream"
+	"github.com/rclone/rclone/fs"
+)
+
+func init() {
+	registerPolicy("all", &All{})
+}
+
+// All policy behaves the same as EpAll except for the CREATE category
+// Action category: same as epall.
+// Create category: apply to all branches.
+// Search category: same as epall.
+type All struct {
+	EpAll
+}
+
+// Create category policy, governing the creation of files and directories
+func (p *All) Create(ctx context.Context, upstreams []*upstream.Fs, path string) ([]*upstream.Fs, error) {
+	if len(upstreams) == 0 {
+		return nil, fs.ErrorObjectNotFound
+	}
+	upstreams = filterNC(upstreams)
+	if len(upstreams) == 0 {
+		return nil, fs.ErrorPermissionDenied
+	}
+	return upstreams, nil
+}
+
+// CreateEntries is CREATE category policy but receving a set of candidate entries
+func (p *All) CreateEntries(entries ...upstream.Entry) ([]upstream.Entry, error) {
+	if len(entries) == 0 {
+		return nil, fs.ErrorObjectNotFound
+	}
+	entries = filterNCEntries(entries)
+	if len(entries) == 0 {
+		return nil, fs.ErrorPermissionDenied
+	}
+	return entries, nil
+}