small refactor*

server/pkg/go-nfs/nfs_onreaddirplus.go

@@ -0,0 +1,153 @@
+package nfs
+
+import (
+	"bytes"
+	"context"
+	"path"
+
+	"github.com/willscott/go-nfs-client/nfs/xdr"
+)
+
+type readDirPlusArgs struct {
+	Handle      []byte
+	Cookie      uint64
+	CookieVerif uint64
+	DirCount    uint32
+	MaxCount    uint32
+}
+
+type readDirPlusEntity struct {
+	FileID     uint64
+	Name       []byte
+	Cookie     uint64
+	Attributes *FileAttribute `xdr:"optional"`
+	Handle     *[]byte        `xdr:"optional"`
+	Next       bool
+}
+
+func joinPath(parent []string, elements ...string) []string {
+	joinedPath := make([]string, 0, len(parent)+len(elements))
+	joinedPath = append(joinedPath, parent...)
+	joinedPath = append(joinedPath, elements...)
+	return joinedPath
+}
+
+func onReadDirPlus(ctx context.Context, w *response, userHandle Handler) error {
+	w.errorFmt = opAttrErrorFormatter
+	obj := readDirPlusArgs{}
+	if err := xdr.Read(w.req.Body, &obj); err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+
+	// in case of test, nfs-client send:
+	// DirCount = 512
+	// MaxCount = 4096
+	if obj.DirCount < 512 || obj.MaxCount < 4096 {
+		return &NFSStatusError{NFSStatusTooSmall, nil}
+	}
+
+	fs, p, err := userHandle.FromHandle(ctx, obj.Handle)
+	if err != nil {
+		return &NFSStatusError{NFSStatusStale, err}
+	}
+
+	contents, verifier, err := getDirListingWithVerifier(ctx, userHandle, obj.Handle, obj.CookieVerif)
+	if err != nil {
+		return err
+	}
+	if obj.Cookie > 0 && obj.CookieVerif > 0 && verifier != obj.CookieVerif {
+		return &NFSStatusError{NFSStatusBadCookie, nil}
+	}
+
+	entities := make([]readDirPlusEntity, 0)
+	dirBytes := uint32(0)
+	maxBytes := uint32(100) // conservative overhead measure
+
+	started := obj.Cookie == 0
+	if started {
+		// add '.' and '..' to entities
+		dotdotFileID := uint64(0)
+		if len(p) > 0 {
+			dda := tryStat(ctx, fs, p[0:len(p)-1])
+			if dda != nil {
+				dotdotFileID = dda.Fileid
+			}
+		}
+		dotFileID := uint64(0)
+		da := tryStat(ctx, fs, p)
+		if da != nil {
+			dotFileID = da.Fileid
+		}
+		entities = append(entities,
+			readDirPlusEntity{Name: []byte("."), Cookie: 0, Next: true, FileID: dotFileID, Attributes: da},
+			readDirPlusEntity{Name: []byte(".."), Cookie: 1, Next: true, FileID: dotdotFileID},
+		)
+	}
+
+	eof := true
+	maxEntities := userHandle.HandleLimit() / 2
+	fb := 0
+	fss := 0
+	for i, c := range contents {
+		// cookie equates to index within contents + 2 (for '.' and '..')
+		cookie := uint64(i + 2)
+		fb++
+		if started {
+			fss++
+			dirBytes += uint32(len(c.Name()) + 20)
+			maxBytes += 512 // TODO: better estimation.
+			if dirBytes > obj.DirCount || maxBytes > obj.MaxCount || len(entities) > maxEntities {
+				eof = false
+				break
+			}
+
+			filePath := joinPath(p, c.Name())
+			handle := userHandle.ToHandle(ctx, fs, filePath)
+			attrs := ToFileAttribute(c, path.Join(filePath...))
+			entities = append(entities, readDirPlusEntity{
+				FileID:     attrs.Fileid,
+				Name:       []byte(c.Name()),
+				Cookie:     cookie,
+				Attributes: attrs,
+				Handle:     &handle,
+				Next:       true,
+			})
+		} else if cookie == obj.Cookie {
+			started = true
+		}
+	}
+
+	writer := bytes.NewBuffer([]byte{})
+	if err := xdr.Write(writer, uint32(NFSStatusOk)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := WritePostOpAttrs(writer, tryStat(ctx, fs, p)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := xdr.Write(writer, verifier); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	if err := xdr.Write(writer, len(entities) > 0); err != nil { // next
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if len(entities) > 0 {
+		entities[len(entities)-1].Next = false
+		// no next for last entity
+
+		for _, e := range entities {
+			if err := xdr.Write(writer, e); err != nil {
+				return &NFSStatusError{NFSStatusServerFault, err}
+			}
+		}
+	}
+	if err := xdr.Write(writer, eof); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	// TODO: track writer size at this point to validate maxcount estimation and stop early if needed.
+
+	if err := w.Write(writer.Bytes()); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	return nil
+}