Added support for advance KV-queries

https://jira.hyperledger.org/browse/FAB-192

Change-Id: I04bf6a03247b38fdc49b7084182c4f70e09c7cdd
Signed-off-by: manish <manish.sethi@gmail.com>

core/ledger/kvledger/txmgmt/couchdbtxmgmt/couchdb_query_executer.go

@@ -56,3 +56,8 @@ func (q *CouchDBQueryExecutor) GetTransactionsForKey(namespace string, key strin
 func (q *CouchDBQueryExecutor) ExecuteQuery(query string) (ledger.ResultsIterator, error) {
 	return nil, errors.New("Not supported by KV data model")
 }
+
+// Done implements method in interface `ledger.QueryExecutor`
+func (q *CouchDBQueryExecutor) Done() {
+	//TODO - acquire lock when constructing and release the lock here
+}

core/ledger/kvledger/txmgmt/lockbasedtxmgmt/lockbased_query_executer.go

@@ -25,10 +25,12 @@ import (
 // RWLockQueryExecutor is a query executor used in `LockBasedTxMgr`
 type RWLockQueryExecutor struct {
 	txmgr *LockBasedTxMgr
+	done  bool
 }
 
 // GetState implements method in interface `ledger.QueryExecutor`
 func (q *RWLockQueryExecutor) GetState(ns string, key string) ([]byte, error) {
+	q.checkDone()
 	var value []byte
 	var err error
 	if value, _, err = q.txmgr.getCommittedValueAndVersion(ns, key); err != nil {
@@ -39,12 +41,29 @@ func (q *RWLockQueryExecutor) GetState(ns string, key string) ([]byte, error) {
 
 // GetStateMultipleKeys implements method in interface `ledger.QueryExecutor`
 func (q *RWLockQueryExecutor) GetStateMultipleKeys(namespace string, keys []string) ([][]byte, error) {
-	return nil, errors.New("Not yet implemented")
+	var results [][]byte
+	var value []byte
+	var err error
+	for _, key := range keys {
+		if value, err = q.GetState(namespace, key); err != nil {
+			return nil, err
+		}
+		results = append(results, value)
+	}
+	return results, nil
 }
 
 // GetStateRangeScanIterator implements method in interface `ledger.QueryExecutor`
+// startKey is included in the results and endKey is excluded. An empty startKey refers to the first available key
+// and an empty endKey refers to the last available key. For scanning all the keys, both the startKey and the endKey
+// can be supplied as empty strings. However, a full scan shuold be used judiciously for performance reasons.
 func (q *RWLockQueryExecutor) GetStateRangeScanIterator(namespace string, startKey string, endKey string) (ledger.ResultsIterator, error) {
-	return nil, errors.New("Not yet implemented")
+	q.checkDone()
+	scanner, err := q.txmgr.getCommittedRangeScanner(namespace, startKey, endKey)
+	if err != nil {
+		return nil, err
+	}
+	return &qKVItr{scanner}, nil
 }
 
 // GetTransactionsForKey - implements method in interface `ledger.QueryExecutor`
@@ -56,3 +75,39 @@ func (q *RWLockQueryExecutor) GetTransactionsForKey(namespace string, key string
 func (q *RWLockQueryExecutor) ExecuteQuery(query string) (ledger.ResultsIterator, error) {
 	return nil, errors.New("Not supported by KV data model")
 }
+
+// Done implements method in interface `ledger.TxSimulator`
+func (q *RWLockQueryExecutor) Done() {
+	q.done = true
+	q.txmgr.commitRWLock.RUnlock()
+}
+
+func (q *RWLockQueryExecutor) checkDone() {
+	if q.done {
+		panic("This method should not be called after calling Done()")
+	}
+}
+
+type qKVItr struct {
+	s *kvScanner
+}
+
+// Next implements Next() method in ledger.ResultsIterator
+func (itr *qKVItr) Next() (ledger.QueryResult, error) {
+	committedKV, err := itr.s.next()
+	if err != nil {
+		return nil, err
+	}
+	if committedKV == nil {
+		return nil, nil
+	}
+	if committedKV.isDelete() {
+		return itr.Next()
+	}
+	return &ledger.KV{Key: committedKV.key, Value: committedKV.value}, nil
+}
+
+// Close implements Close() method in ledger.ResultsIterator
+func (itr *qKVItr) Close() {
+	itr.s.close()
+}

core/ledger/kvledger/txmgmt/lockbasedtxmgmt/lockbased_tx_simulator.go

@@ -20,6 +20,7 @@ import (
 	"errors"
 	"reflect"
 
+	"github.com/hyperledger/fabric/core/ledger"
 	"github.com/hyperledger/fabric/core/ledger/kvledger/txmgmt"
 	logging "github.com/op/go-logging"
 )
@@ -42,7 +43,6 @@ func newNsRWs() *nsRWs {
 type LockBasedTxSimulator struct {
 	RWLockQueryExecutor
 	rwMap map[string]*nsRWs
-	done  bool
 }
 
 func (s *LockBasedTxSimulator) getOrCreateNsRWHolder(ns string) *nsRWs {
@@ -57,6 +57,7 @@ func (s *LockBasedTxSimulator) getOrCreateNsRWHolder(ns string) *nsRWs {
 
 // GetState implements method in interface `ledger.TxSimulator`
 func (s *LockBasedTxSimulator) GetState(ns string, key string) ([]byte, error) {
+	s.checkDone()
 	logger.Debugf("Get state [%s:%s]", ns, key)
 	nsRWs := s.getOrCreateNsRWHolder(ns)
 	// check if it was written
@@ -106,11 +107,24 @@ func (s *LockBasedTxSimulator) GetState(ns string, key string) ([]byte, error) {
 	return value, nil
 }
 
+// GetStateRangeScanIterator implements method in interface `ledger.QueryExecutor`
+// startKey is included in the results and endKey is excluded. An empty startKey refers to the first available key
+// and an empty endKey refers to the last available key. For scanning all the keys, both the startKey and the endKey
+// can be supplied as empty strings. However, a full scan shuold be used judiciously for performance reasons.
+// TODO: The range scan queries still do not support Read-Your_Write (RYW)
+// semantics as it is still not agreed upon whether we want RYW model or not.
+func (s *LockBasedTxSimulator) GetStateRangeScanIterator(namespace string, startKey string, endKey string) (ledger.ResultsIterator, error) {
+	s.checkDone()
+	scanner, err := s.txmgr.getCommittedRangeScanner(namespace, startKey, endKey)
+	if err != nil {
+		return nil, err
+	}
+	return &sKVItr{scanner, s}, nil
+}
+
 // SetState implements method in interface `ledger.TxSimulator`
 func (s *LockBasedTxSimulator) SetState(ns string, key string, value []byte) error {
-	if s.done {
-		panic("This method should not be called after calling Done()")
-	}
+	s.checkDone()
 	nsRWs := s.getOrCreateNsRWHolder(ns)
 	kvWrite, ok := nsRWs.writeMap[key]
 	if ok {
@@ -126,12 +140,6 @@ func (s *LockBasedTxSimulator) DeleteState(ns string, key string) error {
 	return s.SetState(ns, key, nil)
 }
 
-// Done implements method in interface `ledger.TxSimulator`
-func (s *LockBasedTxSimulator) Done() {
-	s.done = true
-	s.txmgr.commitRWLock.RUnlock()
-}
-
 func (s *LockBasedTxSimulator) getTxReadWriteSet() *txmgmt.TxReadWriteSet {
 	txRWSet := &txmgmt.TxReadWriteSet{}
 	sortedNamespaces := getSortedKeys(s.rwMap)
@@ -186,15 +194,43 @@ func (s *LockBasedTxSimulator) GetTxSimulationResults() ([]byte, error) {
 
 // SetStateMultipleKeys implements method in interface `ledger.TxSimulator`
 func (s *LockBasedTxSimulator) SetStateMultipleKeys(namespace string, kvs map[string][]byte) error {
-	return errors.New("Not yet implemented")
-}
-
-// CopyState implements method in interface `ledger.TxSimulator`
-func (s *LockBasedTxSimulator) CopyState(sourceNamespace string, targetNamespace string) error {
-	return errors.New("Not yet implemented")
+	for k, v := range kvs {
+		if err := s.SetState(namespace, k, v); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 // ExecuteUpdate implements method in interface `ledger.TxSimulator`
 func (s *LockBasedTxSimulator) ExecuteUpdate(query string) error {
 	return errors.New("Not supported by KV data model")
 }
+
+type sKVItr struct {
+	scanner   *kvScanner
+	simulator *LockBasedTxSimulator
+}
+
+// Next implements Next() method in ledger.ResultsIterator
+func (itr *sKVItr) Next() (ledger.QueryResult, error) {
+	committedKV, err := itr.scanner.next()
+	if err != nil {
+		return nil, err
+	}
+	if committedKV == nil {
+		return nil, nil
+	}
+	if committedKV.isDelete() {
+		return itr.Next()
+	}
+	nsRWs := itr.simulator.getOrCreateNsRWHolder(itr.scanner.namespace)
+	nsRWs.readMap[committedKV.key] = &kvReadCache{
+		&txmgmt.KVRead{Key: committedKV.key, Version: committedKV.version}, committedKV.value}
+	return &ledger.KV{Key: committedKV.key, Value: committedKV.value}, nil
+}
+
+// Close implements Close() method in ledger.ResultsIterator
+func (itr *sKVItr) Close() {
+	itr.scanner.close()
+}