.

wcfs/btree.go

@@ -36,7 +36,7 @@ type KEY int64
 // are chained together via 'next', so that the entire BTree contents
 // can be traversed in sorted order quickly and easily.
 type ZBucket struct {
-	pyobj *pyObject
+	*pyObject
 
 	next   *ZBucket		// the bucket with the next-larger keys
 	keys   []KEY		// 'len' keys, in increasing order
@@ -54,7 +54,7 @@ type zBTreeItem struct {
 // See https://github.com/zopefoundation/BTrees/blob/4.5.0-1-gc8bf24e/BTrees/Development.txt#L198
 // for details.
 type ZBTree struct {
-	pyobj *pyObject
+	*pyObject
 
 	// firstbucket points to the bucket containing the smallest key in
 	// the BTree.  This is found by traversing leftmost child pointers
@@ -154,7 +154,7 @@ func (t *ZBTree) PDeactivate() {
 	// XXX check if activated?
 	t.firstbucket = nil
 	t.data = nil
-	t.pyobj.PDeactivate()
+	t.pyObject.PDeactivate()
 }
 
 func (t *ZBTree) PActivate(ctx context.Context) error {
@@ -186,18 +186,18 @@ func (b *ZBucket) PDeactivate() {
 	b.next = nil
 	b.keys = nil
 	b.values = nil
-	b.pyobj.PDeactivate()
+	b.pyObject.PDeactivate()
 }
 
 
 func (b *ZBucket) PActivate(ctx context.Context) error {
 	// XXX check if already activated
-	err := b.pyobj.PActivate(ctx)
+	err := b.pyObject.PActivate(ctx)
 	if err != nil {
 		return err
 	}
 
-	t, ok := b.pyobj.pystate.(pickle.Tuple)
+	t, ok := b.pyObject.pystate.(pickle.Tuple)
 	if !ok || !(1 <= len(t) && len(t) <= 2) {
 		// XXX complain
 	}
@@ -239,12 +239,12 @@ func (b *ZBucket) PActivate(ctx context.Context) error {
 
 // ----------------------------------------
 
-func bucketNew(pyobj *pyObject) interface{} {
-	return &ZBucket{pyobj: pyobj}
+func bucketNew(pyobj *pyObject) PyObject {
+	return &ZBucket{pyObject: pyobj}
 }
 
-func btreeNew(pyobj *pyObject) interface{} {
-	return &ZBTree{pyobj: pyobj}
+func btreeNew(pyobj *pyObject) PyObject {
+	return &ZBTree{pyObject: pyobj}
 }
 
 func init() {

wcfs/zodb.go

@@ -24,6 +24,23 @@ import (
 	pickle "github.com/kisielk/og-rek"
 )
 
+// Object is the interface that every object representing any ZODB object implements.
+type Object interface {
+	Jar()    *Connection
+	Oid()    zodb.Oid
+	Serial() zodb.Tid
+
+	// XXX activate/deactivate/invalidate here?
+}
+
+// PyObject is the interface that every object representing Python ZODB object implements.
+type PyObject interface {
+	Object
+
+	PyClass() pickle.Class
+	// PyState?
+}
+
 // object is common base for in-process representation of ZODB object.
 type object struct {
 	jar	*Connection
@@ -31,6 +48,10 @@ type object struct {
 	serial	zodb.Tid
 }
 
+func (obj *object) Jar() *Connection	{ return obj.jar	}
+func (obj *object) Oid() zodb.Oid	{ return obj.oid	}
+func (obj *object) Serial() zodb.Tid	{ return obj.serial	}
+
 // pyObject is common base for in-process representation of ZODB Python objects.
 type pyObject struct {
 	object
@@ -39,6 +60,9 @@ type pyObject struct {
 	pystate interface{}  // object state. python passes this to pyclass.__new__().__setstate__()
 }
 
+func (pyobj *pyObject) PyClass() pickle.Class	{ return pyobj.pyclass	}
+
+
 // Connection represents a view of ZODB database.
 //
 // The view is representing state of ZODB objects as of `at` transaction.
@@ -232,24 +256,26 @@ func (e *wrongClassError) Error() string {
 //
 // 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) (interface{}/*PyObject*/, error) {
+func (conn *Connection) get(pyclass pickle.Class, oid zodb.Oid) (PyObject, error) {
 	conn.objmu.Lock()		// XXX -> rlock
 	wobj := conn.objtab[oid]
-	var xobj interface{}
+	var pyobj PyObject
 	checkClass := false
 	if wobj != nil {
-		xobj = wobj.Get()
+		if xobj := wobj.Get(); xobj != nil {
+			pyobj = xobj.(PyObject)
+		}
 	}
-	if xobj == nil {
-		xobj = conn.newGhost(pyclass, oid)
-		conn.objtab[oid] = NewWeakRef(xobj)
+	if pyobj == nil {
+		pyobj = conn.newGhost(pyclass, oid)
+		conn.objtab[oid] = NewWeakRef(pyobj)
 	} else {
 		checkClass = true
 	}
 	conn.objmu.Unlock()
 
 	if checkClass {
-		if cls := xobj.PyClass(); pyclass != cls {
+		if cls := pyobj.PyClass(); pyclass != cls {
 			return nil, &zodb.OpError{
 				URL:  conn.stor.URL(),
 				Op:   fmt.Sprintf("@%s: get", conn.at), // XXX abuse
@@ -259,7 +285,7 @@ func (conn *Connection) get(pyclass pickle.Class, oid zodb.Oid) (interface{}/*Py
 		}
 	}
 
-	return xobj, nil
+	return pyobj, nil
 }
 
 
@@ -364,18 +390,18 @@ func (conn *Connection) loadpy(ctx context.Context, oid zodb.Oid) (pyclass pickl
 }
 
 // path(class) -> new(pyobj)
-var classTab = make(map[string]func(*pyObject)interface{})
+var classTab = make(map[string]func(*pyObject)PyObject)
 
 // registerClass registers python class to be transformed to Go instance
 // created via classNew.
 //
 // must be called from global init().
-func registerClass(classPath string, classNew func(*pyObject)interface{}) {
+func registerClass(classPath string, classNew func(*pyObject)PyObject) {
 	classTab[classPath] = classNew
 }
 
 // newGhost creates new ghost object corresponding to pyclass and oid.
-func (conn *Connection) newGhost(pyclass pickle.Class, oid zodb.Oid) interface{} {
+func (conn *Connection) newGhost(pyclass pickle.Class, oid zodb.Oid) PyObject {
 	pyobj := &pyObject{
 		object:  object{jar: conn, oid: oid, serial: 0},
 		pyclass: pyclass,