go/zodb/zeo: Factor-out tuple handling into encoding

Handle pickled lists as valid input when decoding tuples.

go/zodb/storage/zeo/proto.go

@@ -98,7 +98,7 @@ func pktDecodeZ(pkb *pktBuf) (msg, error) {
 		return m, err
 	}
 
-	tpkt, ok := xpkt.(pickle.Tuple) // XXX also list?
+	tpkt, ok := encoding('Z').asTuple(xpkt)
 	if !ok {
 		return m, derrf("got %T; expected tuple", xpkt)
 	}
@@ -134,6 +134,41 @@ func derrf(format string, argv ...interface{}) error {
 
 // ---- retrieve/put objects from/into msg.arg ----
 
+// tuple represents py tuple.
+type tuple []interface{}
+
+// Tuple converts t into corresponding object appropriate for encoding e.
+func (e encoding) Tuple(t tuple) pickle.Tuple {
+	switch e {
+	default:
+		panic("bug")
+
+	case 'Z':
+		// pickle: -> pickle.Tuple
+		return pickle.Tuple(t)
+	}
+}
+
+// asTuple tries to retrieve tuple from corresponding object decoded via encoding e.
+func (e encoding) asTuple(xt interface{}) (tuple, bool) {
+	switch e {
+	default:
+		panic("bug")
+
+	case 'Z':
+		// pickle: tuples are represented by pickle.Tuple; lists as []interface{}
+		switch t := xt.(type) {
+		case pickle.Tuple:
+			return tuple(t), true
+		case []interface{}:
+			return tuple(t), true
+		default:
+			return tuple(nil), false
+		}
+	}
+}
+
+
 // xuint64Unpack tries to decode packed 8-byte string as bigendian uint64
 func (e encoding) xuint64Unpack(xv interface{}) (uint64, bool) {
 	switch e {

go/zodb/storage/zeo/zeo.go

@@ -86,7 +86,7 @@ func (z *zeo) Load(ctx context.Context, xid zodb.Xid) (buf *mem.Buf, serial zodb
 	}
 
 	// (data, serial, next_serial | None)
-	res, ok := xres.(pickle.Tuple)
+	res, ok := enc.asTuple(xres)
 	if !ok || len(res) != 3 {
 		return nil, 0, rpc.ereplyf("got %#v; expect 3-tuple", res)
 	}
@@ -140,7 +140,7 @@ type rpc struct {
 // rpcExcept represents generic exception
 type rpcExcept struct {
 	exc  string
-	argv []interface{}
+	argv tuple
 }
 
 func (r *rpcExcept) Error() string {
@@ -175,7 +175,7 @@ func (r rpc) call(ctx context.Context, argv ...interface{}) (interface{}, error)
 //
 // well-known exceptions are mapped to corresponding well-known errors - e.g.
 // POSKeyError -> zodb.NoObjectError, and rest are returned wrapper into rpcExcept.
-func (r rpc) excError(exc string, argv []interface{}) error {
+func (r rpc) excError(exc string, argv tuple) error {
 	// translate well-known exceptions
 	switch exc {
 	case "ZODB.POSException.POSKeyError":
@@ -204,13 +204,13 @@ func (r rpc) excError(exc string, argv []interface{}) error {
 func (r rpc) zeo5Error(arg interface{}) error {
 	enc := r.zlink.enc
 	// ('type', (arg1, arg2, arg3, ...))
-	texc, ok := arg.(pickle.Tuple)
+	texc, ok := enc.asTuple(arg)
 	if !ok || len(texc) != 2 {
 		return r.ereplyf("except5: got %#v; expect 2-tuple", arg)
 	}
 
 	exc, ok1 := enc.asString(texc[0])
-	argv, ok2 := texc[1].(pickle.Tuple)
+	argv, ok2 := enc.asTuple(texc[1])
 	if !(ok1 && ok2) {
 		return r.ereplyf("except5: got (%T, %T); expect (str, tuple)", texc...)
 	}
@@ -277,7 +277,7 @@ func (r rpc) zeo4Error(arg interface{}) error {
 		argv = args
 	}
 
-	return r.excError(exc, argv)
+	return r.excError(exc, tuple(argv))
 }
 
 // isPyExceptClass returns whether klass represents python exception

go/zodb/storage/zeo/zrpc.go

@@ -30,8 +30,6 @@ import (
 	"net"
 	"sync"
 
-	pickle "github.com/kisielk/og-rek"
-
 	"github.com/someonegg/gocontainer/rbuf"
 	"lab.nexedi.com/kirr/go123/xbytes"
 	"lab.nexedi.com/kirr/go123/xerr"
@@ -188,7 +186,7 @@ func (zl *zLink) Call(ctx context.Context, method string, argv ...interface{}) (
 			msgid:  callID,
 			flags:  0,
 			method: method,
-			arg:    pickle.Tuple(argv),
+			arg:    zl.enc.Tuple(argv),
 	})
 
 	// ok, pkt is ready to go