.

wcfs/btree.go

@@ -126,6 +126,11 @@ func (b *ZBucket) get(key KEY) (interface{}, bool) {
 	return b.values[i], true
 }
 
+// XXX ZBucket.MinKey ?
+// XXX ZBucket.MaxKey ?
+
+
+// ---- serialization ----
 
 // from https://github.com/zopefoundation/BTrees/blob/4.5.0-1-gc8bf24e/BTrees/BTreeTemplate.c#L1087:
 //
@@ -153,22 +158,18 @@ func (b *ZBucket) get(key KEY) (interface{}, bool) {
 //
 // In the above, key[i] means self->data[i].key, and similarly for child[i].
 
-func (t *ZBTree) PDeactivate() {
-	// XXX check if activated?
+// DropState implements Stateful.
+func (t *ZBTree) DropState() {
 	t.firstbucket = nil
 	t.data = nil
-	t.pyObject.PDeactivate()
 }
 
-func (t *ZBTree) PActivate(ctx context.Context) error {
+// PySetState implements PyStateful to set btree data from pystate.
+func (t *ZBTree) PySetState(pystate interface{}) error {
 	panic("TODO")
 }
 
 
-// XXX ZBucket.MinKey ?
-// XXX ZBucket.MaxKey ?
-
-
 // from https://github.com/zopefoundation/BTrees/blob/4.5.0-1-gc8bf24e/BTrees/BucketTemplate.c#L1195:
 //
 // For a mapping bucket (self->values is not NULL), a one-tuple or two-tuple.
@@ -182,41 +183,16 @@ func (t *ZBTree) PActivate(ctx context.Context) error {
 //	     <self->next iff non-NULL>
 //	)
 
-
-
-// PDeactivate implements Object.
-func (b *ZBucket) PDeactivate() {
-	// XXX check if activated
-	// b.pyObject.PDeactivate() ...
+// DropState implements Stateful to discard bucket state.
+func (b *ZBucket) DropState() {
 	b.next = nil
 	b.keys = nil
 	b.values = nil
-	b.pyObject.PDeactivate()
-}
-
-
-// PActivate implements Object.
-func (b *ZBucket) PActivate(ctx context.Context) (bool, error) {
-	activated, err := b.pyObject.PActivate(ctx)
-	if err != nil {
-		return err
-	}
-	if !activated {
-		return false, nil
-	}
-
-	// FIXME other users must wait for first decode to complete
-	err = b.decode()
-	if err != nil {
-		b.pyObject.PDeactivate()
-		return false, err
-	}
-
-	return true, nil
 }
 
-func (b *ZBucket) decode() error {
-	t, ok := b.pyObject.pystate.(pickle.Tuple)
+// PySetState implements PyStateful to set bucket data from pystate.
+func (b *ZBucket) PySetState(pystate interface{}) error {
+	t, ok := pystate.(pickle.Tuple)
 	if !ok || !(1 <= len(t) && len(t) <= 2) {
 		// XXX complain
 	}
@@ -256,7 +232,7 @@ func (b *ZBucket) decode() error {
 }
 
 
-// ----------------------------------------
+// ---- register classes to ZODB ----
 
 func bucketNew(pyobj *pyObject) PyObject {
 	return &ZBucket{pyObject: pyobj}

wcfs/wcfs.go

@@ -468,7 +468,7 @@ func (bf *BigFile) Read(_ nodefs.File, dest []byte, off int64, _ fuse.Context) (
 // TODO set it to Connection.CacheControl
 type zodbCacheControl struct {}
 
-func (cc *zodbCacheControl) WantEvict(obj Object) {
+func (cc *zodbCacheControl) WantEvict(obj Object) bool {
 	switch obj.(type) {
 	default:
 		return true

wcfs/zblk.go

@@ -94,19 +94,16 @@ func (conn *zpyconn) loadZBigFile(ctx context.Context, oid zodb.Oid) (*ZBigFile,
 */
 
 
-func (bf *ZBigFile) PDeactivate() {
-	if bf.blktab == nil {
-		return
-	}
-
+// DropState implements Stateful.
+func (bf *ZBigFile) DropState() {
 	bf.blksize = -1
 	bf.blktab  = nil
-	bf.pyObject.PDeactivate()
 }
 
 
+func (bf *ZBigFile) PySetState(pystate interface{}) (err error) {
+	panic("TODO")
 /* XXX reenable (pickletools)
-func (bf *ZBigFile) PActivate(ctx context.Context) (err error) {
 	if bf.blktab != nil {
 		return nil
 	}
@@ -137,8 +134,8 @@ func (bf *ZBigFile) PActivate(ctx context.Context) (err error) {
 	bf.blksize = blksize
 	bf.blktab  = blktab
 	return nil
-}
 */
+}
 
 
 // XXX -> newGhost

wcfs/zodb.go

@@ -48,7 +48,7 @@ type Object interface {
 	//
 	// Object data must be accessed only after corresponding PActivate
 	// call, which marks that object's data as being in use.
-	PActivate(ctx context.Context) (activated bool, _ error)	// XXX ret semantics?
+	PActivate(ctx context.Context) error
 
 	// PDeactivate indicates that corresponding PActivate caller finished access to object's data.
 	//
@@ -63,7 +63,7 @@ type Object interface {
 	//
 	// Besides exotic cases, the caller thus must not use object's data
 	// after PDeactivate call.
-	PDeactivate()	// XXX + -> nuse ?
+	PDeactivate()
 
 	// PInvalidate requests in-RAM object data to be discarded.
 	//
@@ -86,16 +86,36 @@ type Object interface {
 	PInvalidate()
 }
 
+// XXX
+type Stateful interface {
+	// XXX
+	DropState()
+}
+
 // PyObject is the interface that every in-RAM object representing Python ZODB object implements.
 type PyObject interface {
 	Object
 
 	PyClass() pickle.Class // python class of this object
-	PyState() interface{}  // object state. python passes this to pyclass.__new__().__setstate__()
+//	PyState() interface{}  // object state. python passes this to pyclass.__new__().__setstate__()
+
+	PyStateful
+}
 
+// XXX
+type PyStateful interface {
+	Stateful
+
+	// PySetState should set Python state of the in-RAM object.
+	// Analog of __setstate__() in Python.
+	PySetState(pystate interface{}) error
+
+	// PyGetState should return Python state of in-RAM object.
+	// Analog of __getstate__() in Python.
+	//PyGetState() interface{}	XXX
 }
 
-// object is common base for in-RAM representation of ZODB objects.
+// object is common base for in-RAM implementations of ZODB objects.
 type object struct {
 	jar	*Connection
 	oid	zodb.Oid
@@ -108,18 +128,19 @@ func (obj *object) PJar() *Connection	{ return obj.jar	}
 func (obj *object) POid() zodb.Oid	{ return obj.oid	}
 func (obj *object) PSerial() zodb.Tid	{ return obj.serial	}
 
-// pyObject is common base for in-RAM representation of ZODB Python objects.
+// pyObject is common base for in-RAM implementations of ZODB Python objects.
 type pyObject struct {
 	object
 
-	pyclass pickle.Class
-	pystate interface{}
-	loaderr error		// if there was error at state loading
-	ready   chan struct{}	// activation complete
+	pyclass  pickle.Class
+//	pystate  interface{}
+	instance PyStateful
+	loaderr  error		// if there was error at state loading
+	ready    chan struct{}	// activation complete
 }
 
 func (pyobj *pyObject) PyClass() pickle.Class	{ return pyobj.pyclass	}
-func (pyobj *pyObject) PyState() interface{}	{ return pyobj.pystate	}
+//func (pyobj *pyObject) PyState() interface{}	{ return pyobj.pystate	}
 
 
 // Connection represents a view of ZODB database.
@@ -338,7 +359,7 @@ func (conn *Connection) newGhost(pyclass pickle.Class, oid zodb.Oid) PyObject {
 	pyobj := &pyObject{
 		object:  object{jar: conn, oid: oid, serial: 0},
 		pyclass: pyclass,
-		pystate: nil,
+		//instance: nil,
 	}
 
 	// switch on pyclass and transform e.g. "zodb.BTree.Bucket" -> *ZBucket
@@ -347,7 +368,9 @@ func (conn *Connection) newGhost(pyclass pickle.Class, oid zodb.Oid) PyObject {
 		return pyobj	// XXX or return error here?
 	}
 
-	return classNew(pyobj)
+	obj := classNew(pyobj)
+	pyobj.instance = obj
+	return obj
 }
 
 
@@ -368,14 +391,18 @@ func (obj *object) PDeactivate() {
 
 // object's pactivate & friends that only manage base activation state, without actually loading data.
 
-func (obj *object) pactivate(ctx context.Context) error {
+// XXX -> incref ?
+func (obj *object) pactivate() (load bool) {
 	nuse := atomic.AddInt32(&obj.refcnt, +1)
 	if nuse == 1 {
 		// we become responsible for loading object's data.
-		// XXX check state
+		// XXX also check state (it could be already loaded, but with refcnt=0)
+		return true
 	}
+	return false
 }
 
+// XXX -> decref ?
 func (obj *object) pdeactivate() (drop bool) {
 	nuse := atomic.AddInt32(&obj.refcnt, -1)
 	if nuse < 0 {
@@ -389,14 +416,16 @@ func (obj *object) pdeactivate() (drop bool) {
 	// TODO state=modified -> don't drop.
 	drop = true
 
+	// XXX -> pyObject?
 	if drop {
 		if cc := obj.jar.cacheControl; cc != nil {
-			drop = cc.WantEvict(obj)
+			drop = cc.WantEvict(obj.instance)
 		}
 	}
 
 	if drop {
 		obj.serial  = 0
+		//obj.insance.DropState()
 	}
 
 	return drop
@@ -404,16 +433,23 @@ func (obj *object) pdeactivate() (drop bool) {
 
 
 // PActivate implements Object.
-func (pyobj *pyObject) PActivate(ctx context.Context) (bool, error) {
+func (pyobj *pyObject) PActivate(ctx context.Context) (err error) {
 	load := pyobj.object.pactivate()
+	defer func() {
+		if err != nil {
+			// no need to check for drop - the state is already
+			// dropped - we just need to decref here.
+			pyobj.object.pdeactivate()
+		}
+	}()
 	if !load {
 		// someone else is already activated/activating the object.
 		// wait for its loading to complete and we are done.
 		select {
-		case <-ctx.Done:
-			return false, ctx.Err()		// XXX err ctx
+		case <-ctx.Done():
+			return ctx.Err()		// XXX err ctx
 		case <-pyobj.ready:
-			return (pyobj.loaderr == nil), pyobj.loaderr		// XXX err ctx?
+			return pyobj.loaderr		// XXX err ctx?
 		}
 	}
 
@@ -427,10 +463,19 @@ func (pyobj *pyObject) PActivate(ctx context.Context) (bool, error) {
 	}
 
 	pyobj.serial  = serial
-	pyobj.pystate = pystate
+//	pyobj.pystate = pystate
+
+	if err == nil {
+		err = pyobj.instance.PySetState(pystate)	// XXX err ctx
+	}
+	if err != nil {
+		pyobj.instance.DropState()
+	}
+
 	pyobj.loaderr = err
+
 	close(pyobj.ready)
-	return true, err	// XXX err ctx
+	return err	// XXX err ctx
 }
 
 
@@ -443,12 +488,16 @@ func (pyobj *pyObject) PDeactivate() {
 
 	// we have to drop pyobject state
 	// XXX locking?
-	pyobj.pystate = nil
+//	pyobj.pystate = nil
+	pyobj.instance.DropState()
 	pyobj.loaderr = nil
 	pyobj.ready   = make(chan struct{})
-
-	return drop
 }
 
 // XXX pyobj.PInvalidate()	= deactivate without checking if state != modified
-// XXX panic if refcnt != 0  (object being used)
+func (pyobj *pyObject) PInvalidate() {
+	// XXX panic if refcnt != 0  (object being used)
+	pyobj.instance.DropState()
+	pyobj.loaderr = nil
+	pyobj.ready   = make(chan struct{})
+}