impl/memory: Implement Queries

impl/memory/datastore_data.go

Index: impl/memory/datastore_data.go
diff --git a/impl/memory/datastore_data.go b/impl/memory/datastore_data.go
index 5ef87530ded64c4c31f367bb859d3f87c43b8d7b..2bfc13256f25f08eb97d833be1697c0e02f7090c 100644
--- a/impl/memory/datastore_data.go
+++ b/impl/memory/datastore_data.go
@@ -98,14 +98,14 @@ func curVersion(ents *memCollection, key []byte) int64 {
 	if ents != nil {
 		if v := ents.Get(key); v != nil {
 			pm, err := rpm(v)
-			if err != nil {
-				panic(err) // memory corruption
-			}
+			memoryCorruption(err)
+
 			pl, ok := pm["__version__"]
 			if ok && len(pl) > 0 && pl[0].Type() == ds.PTInt {
 				return pl[0].Value().(int64)
 			}
-			panic(fmt.Errorf("__version__ property missing or wrong: %v", pm))
+
+			memoryCorruption(fmt.Errorf("__version__ property missing or wrong: %v", pm))
 		}
 	}
 	return 0
@@ -247,9 +247,7 @@ func (d *dataStoreData) canApplyTxn(obj memContextObj) bool {
 			continue
 		}
 		k, err := serialize.ReadKey(bytes.NewBufferString(rk), serialize.WithContext, "", "")
-		if err != nil {
-			panic(err)
-		}
+		memoryCorruption(err)
 
 		entKey := "ents:" + k.Namespace()
 		mkey := groupMetaKey(k)
@@ -281,10 +279,7 @@ func (d *dataStoreData) applyTxn(c context.Context, obj memContextObj) {
 				d.putMulti([]ds.Key{m.key}, []ds.PropertyMap{m.data},
 					func(_ ds.Key, e error) { err = e })
 			}
-			err = errors.SingleError(err)
-			if err != nil {
-				panic(err)
-			}
+			impossible(err)
 		}
 	}
 }
@@ -338,10 +333,11 @@ func (td *txnDataStoreData) endTxn() {
 	atomic.StoreInt32(&td.closed, 1)
 }
 func (*txnDataStoreData) applyTxn(context.Context, memContextObj) {
-	panic("txnDataStoreData cannot apply transactions")
+	impossible(fmt.Errorf("cannot creat a recursive transaction"))
 }
 func (*txnDataStoreData) mkTxn(*ds.TransactionOptions) memContextObj {
-	panic("impossible")
+	impossible(fmt.Errorf("cannot creat a recursive transaction"))
+	return nil
 }
 
 func (td *txnDataStoreData) run(f func() error) error {