.

wcfs/btree.go

@@ -79,6 +79,7 @@ func (t *ZBTree) Get(ctx context.Context, key KEY) (interface{}, bool, error) {
 
 	if len(t.data) == 0 {
 		// empty btree
+		t.PDeactivate()
 		return nil, false, nil
 	}
 
@@ -94,13 +95,15 @@ func (t *ZBTree) Get(ctx context.Context, key KEY) (interface{}, bool, error) {
 
 		switch child := t.data[i].child.(type) {
 		case *ZBTree:
-			// XXX t.PAllowDeactivate
+			t.PDeactivate()
 			t = child
 			t.PActivate(ctx)	// XXX err
 
 		case *ZBucket:
+			t.PDeactivate()
 			child.PActivate(ctx)	// XXX err
 			v, ok := child.get(key)
+			child.PDeactivate()
 			return v, ok, nil
 		}
 	}
@@ -181,8 +184,10 @@ func (t *ZBTree) PActivate(ctx context.Context) error {
 
 
 
+// PDeactivate implements Object.
 func (b *ZBucket) PDeactivate() {
 	// XXX check if activated
+	// b.pyObject.PDeactivate() ...
 	b.next = nil
 	b.keys = nil
 	b.values = nil
@@ -200,7 +205,7 @@ func (b *ZBucket) PActivate(ctx context.Context) (bool, error) {
 		return false, nil
 	}
 
-	// FIXME other users must wait for first decode to complet
+	// FIXME other users must wait for first decode to complete
 	err = b.decode()
 	if err != nil {
 		b.pyObject.PDeactivate()

wcfs/zodb.go

@@ -122,15 +122,6 @@ func (pyobj *pyObject) PyClass() pickle.Class	{ return pyobj.pyclass	}
 func (pyobj *pyObject) PyState() interface{}	{ return pyobj.pystate	}
 
 
-// LiveCacheControl is the interface that allows applications to influence
-// Connection's decisions with respect to its live cache.
-type LiveCacheControl interface {
-	// WantEvict is called when object is going to be evicted from live cache and made ghost.
-	// If !ok the object will remain live.
-	WantEvict(obj Object) (ok bool)
-}
-
-
 // Connection represents a view of ZODB database.
 //
 // The view is representing state of ZODB objects as of `at` transaction.
@@ -200,6 +191,17 @@ type Connection struct {
 	cacheControl LiveCacheControl
 }
 
+// LiveCacheControl is the interface that allows applications to influence
+// Connection's decisions with respect to its live cache.
+type LiveCacheControl interface {
+	// WantEvict is called when object is going to be evicted from live cache and made ghost.
+	// If !ok the object will remain live.
+	WantEvict(obj Object) (ok bool)
+}
+
+
+// ----------------------------------------
+
 
 // Get returns in-RAM object corresponding to specified ZODB object according to current database view.
 //
@@ -211,7 +213,7 @@ type Connection struct {
 // The object's data is not neccessarily loaded after Get returns. Use
 // PActivate to make sure the object ifs fully loaded.
 func (conn *Connection) Get(ctx context.Context, oid zodb.Oid) (interface{} /*PyObject*/, error) {
-	conn.objmu.Lock()
+	conn.objmu.Lock()		// XXX -> rlock
 	wobj := conn.objtab[oid]
 	var xobj interface{}
 	if wobj != nil {
@@ -263,7 +265,7 @@ func (e *wrongClassError) Error() string {
 //
 // XXX object scope.
 //
-// use-case: in ZODB references are (pyclass, oid), so new ghost is created
+// Use-case: in ZODB references are (pyclass, oid), so new ghost is created
 // without further loading anything.
 func (conn *Connection) get(pyclass pickle.Class, oid zodb.Oid) (PyObject, error) {
 	conn.objmu.Lock()		// XXX -> rlock
@@ -298,22 +300,27 @@ func (conn *Connection) get(pyclass pickle.Class, oid zodb.Oid) (PyObject, error
 }
 
 
+// loadpy loads object specified by oid and decodes it as a ZODB Python object.
+//
+// loadpy does not create any in-RAM object associated with Connection.
+// It only returns decoded database data.
 func (conn *Connection) loadpy(ctx context.Context, oid zodb.Oid) (pyclass pickle.Class, pystate interface{}, serial zodb.Tid, _ error) {
 	buf, serial, err := conn.stor.Load(ctx, zodb.Xid{Oid: oid, At: conn.at})
 	if err != nil {
 		return pickle.Class{}, nil, 0, err
 	}
 
+	defer buf.Release()
+
 	pyclass, pystate, err = zodb.PyData(buf.Data).Decode()
 	if err != nil {
 		return pickle.Class{}, nil, 0, err	// XXX err ctx
 	}
 
-	buf.Release()
-
 	return pyclass, pystate, serial, nil
 }
 
+// ---- pyclass -> new ghost ----
 
 // path(class) -> new(pyobj)
 var classTab = make(map[string]func(*pyObject)PyObject)
@@ -445,5 +452,3 @@ func (pyobj *pyObject) PDeactivate() {
 
 // XXX pyobj.PInvalidate()	= deactivate without checking if state != modified
 // XXX panic if refcnt != 0  (object being used)
-
-