Merge pull request #5 from letterbeezps/dev

Dev

Author: letterbeezps

engine/engine.go

@@ -8,18 +8,25 @@ import (
 )
 
 type Engine interface {
+	// requested
 	Get(key string) ([]byte, bool)
 
+	// requested
 	Set(key string, value []byte)
 
+	// requested
 	Delete(key string)
 
+	// option
 	Scan(start, end internal.Bound, iter func(key string, value []byte) bool)
 
+	// option
 	Reverse(start, end internal.Bound, iter func(key string, value []byte) bool)
 
+	// requested
 	Iter(start, end internal.Bound) Iterator
 
+	// option
 	ReverseIter(start, end internal.Bound) Iterator
 }
 
@@ -181,6 +188,12 @@ func ScanTest(engine Engine, t *testing.T) {
 		i++
 	}
 
+	iterator = engine.Iter(
+		internal.NewBound("d", internal.Include),
+		internal.NewBound("", internal.NoBound),
+	)
+	assert.False(t, iterator.IsValid())
+
 	iterator = engine.Iter(
 		internal.NewBound("aab", internal.Include),
 		internal.NewBound("", internal.NoBound),

engine/memory/iterator.go

@@ -15,6 +15,9 @@ type MemoryIterator struct {
 }
 
 func (iter *MemoryIterator) Value() []byte {
+	if len(iter.V) == 0 {
+		return []byte{}
+	}
 	return iter.V
 }
 

engine/memory/memory.go

@@ -89,15 +89,22 @@ func (m *Memory) Iter(start, end internal.Bound) engine.Iterator {
 	iter := m.Data.Iter()
 	key, value := "", []byte{}
 	valid := true
-	switch start.BoundType {
-	case internal.NoBound:
+
+	if start.BoundType == internal.NoBound {
 		valid = iter.First()
-	case internal.Include, internal.Exclude:
+	} else {
 		valid = iter.Seek(start.Key)
-		if valid && start.BoundType == internal.Exclude && iter.Key() == start.Key {
-			valid = iter.Next()
-		}
 	}
+	if valid && start.BoundType == internal.Exclude && iter.Key() == start.Key {
+		valid = iter.Next()
+	}
+	if valid && end.BoundType == internal.Include && iter.Key() > end.Key {
+		valid = false
+	}
+	if valid && end.BoundType == internal.Exclude && iter.Key() >= end.Key {
+		valid = false
+	}
+
 	if valid {
 		key = iter.Key()
 		value = iter.Value()
@@ -111,6 +118,7 @@ func (m *Memory) Iter(start, end internal.Bound) engine.Iterator {
 	}
 }
 
+// todo : fix bug
 func (m *Memory) ReverseIter(start, end internal.Bound) engine.Iterator {
 	iter := m.Data.Iter()
 	key, value := "", []byte{}

mvcc/error.go

@@ -0,0 +1,7 @@
+package mvcc
+
+import "errors"
+
+var (
+	ErrorSerialization = errors.New("serialization")
+)

mvcc/tx.go

@@ -21,7 +21,7 @@ func (tx *TX) Begin() error {
 	tx.Lock.Lock()
 	defer tx.Lock.Unlock()
 
-	txId := uint64(0)
+	txId := uint64(1)
 	txIdBytes, ok := tx.Engine.Get(NextTxID)
 	if ok {
 		txId = binary.BigEndian.Uint64(txIdBytes)
@@ -88,7 +88,7 @@ func (tx *TX) Write(key string, value []byte) error {
 			return errors.Wrap(err, fmt.Sprintf("got bad txKey: %s", iter.Key()))
 		}
 		if !tx.State.IsVisible(check_id) {
-			return errors.Wrap(err, fmt.Sprintf("serialization, cur tx: %d, exist: %d", tx.State.TxID, check_id))
+			return errors.Wrap(ErrorSerialization, fmt.Sprintf("cur tx: %d, exist: %d", tx.State.TxID, check_id))
 		}
 		iter.Next()
 	}
@@ -123,10 +123,14 @@ func (tx *TX) Commit() error {
 	start := internal.NewBound(startKey, internal.Include)
 	end := internal.NewBound(endKey, internal.Exclude)
 	iter := tx.Engine.Iter(start, end)
+	removeKeys := []string{}
 	for iter.IsValid() {
-		tx.Engine.Delete(iter.Key())
+		removeKeys = append(removeKeys, iter.Key())
 		iter.Next()
 	}
+	for _, key := range removeKeys {
+		tx.Engine.Delete(key)
+	}
 
 	activeKey, err := encodeTxActiveKey(tx.State.TxID)
 	if err != nil {
@@ -145,7 +149,9 @@ func (tx *TX) RollBack() error {
 	start := internal.NewBound(startKey, internal.Include)
 	end := internal.NewBound(endKey, internal.Exclude)
 	iter := tx.Engine.Iter(start, end)
+	removeKeys := []string{}
 	for iter.IsValid() {
+		removeKeys = append(removeKeys, iter.Key())
 		_, origin_key, err := decodeTxWriteKey(iter.Key())
 		if err != nil {
 			return errors.Wrap(err, fmt.Sprintf("decodeTxWriteKey with key: %s", iter.Key()))
@@ -154,10 +160,14 @@ func (tx *TX) RollBack() error {
 		if err != nil {
 			return errors.Wrap(err, fmt.Sprintf("encodeTxKey with key: %s", txKey))
 		}
-		tx.Engine.Delete(txKey)
+		removeKeys = append(removeKeys, txKey)
 		iter.Next()
 	}
 
+	for _, key := range removeKeys {
+		tx.Engine.Delete(key)
+	}
+
 	activeKey, err := encodeTxActiveKey(tx.State.TxID)
 	if err != nil {
 		return errors.Wrap(err, fmt.Sprintf("getTxActiveKey with %d", tx.State.TxID))
@@ -188,5 +198,5 @@ func (tx *TX) Get(key string) ([]byte, error) {
 		}
 		iter.Next()
 	}
-	return nil, nil
+	return []byte{}, nil
 }