[FAB-2578] Move utility functions to proper file

https://jira.hyperledger.org/browse/FAB-2578

`CreateNextBlock` and `GetBlock` are utility functions and as such, they
belong to `util.go`.

Change-Id: I74567bdbb508f8d8be00defdfee06e303b3f6379
Signed-off-by: Kostas Christidis <[email protected]>

Author: kchristidis

orderer/ledger/ordererledger.go

@@ -19,8 +19,6 @@ package ordererledger
 import (
 	cb "github.com/hyperledger/fabric/protos/common"
 	ab "github.com/hyperledger/fabric/protos/orderer"
-
-	"github.com/golang/protobuf/proto"
 )
 
 // Factory retrieves or creates new ledgers by chainID
@@ -62,54 +60,3 @@ type ReadWriter interface {
 	Reader
 	Writer
 }
-
-// CreateNextBlock provides a utility way to construct the next block from contents and metadata for a given ledger
-// XXX this will need to be modified to accept marshaled envelopes to accomodate non-deterministic marshaling
-func CreateNextBlock(rl Reader, messages []*cb.Envelope) *cb.Block {
-	var nextBlockNumber uint64
-	var previousBlockHash []byte
-
-	if rl.Height() > 0 {
-		it, _ := rl.Iterator(&ab.SeekPosition{Type: &ab.SeekPosition_Newest{&ab.SeekNewest{}}})
-		<-it.ReadyChan() // Should never block, but just in case
-		block, status := it.Next()
-		if status != cb.Status_SUCCESS {
-			panic("Error seeking to newest block for chain with non-zero height")
-		}
-		nextBlockNumber = block.Header.Number + 1
-		previousBlockHash = block.Header.Hash()
-	}
-
-	data := &cb.BlockData{
-		Data: make([][]byte, len(messages)),
-	}
-
-	var err error
-	for i, msg := range messages {
-		data.Data[i], err = proto.Marshal(msg)
-		if err != nil {
-			panic(err)
-		}
-	}
-
-	block := cb.NewBlock(nextBlockNumber, previousBlockHash)
-	block.Header.DataHash = data.Hash()
-	block.Data = data
-
-	return block
-}
-
-// GetBlock is a utility method for retrieving a single block
-func GetBlock(rl Reader, index uint64) *cb.Block {
-	i, _ := rl.Iterator(&ab.SeekPosition{Type: &ab.SeekPosition_Specified{Specified: &ab.SeekSpecified{Number: index}}})
-	select {
-	case <-i.ReadyChan():
-		block, status := i.Next()
-		if status != cb.Status_SUCCESS {
-			return nil
-		}
-		return block
-	default:
-		return nil
-	}
-}

orderer/ledger/util.go

@@ -17,7 +17,9 @@ limitations under the License.
 package ordererledger
 
 import (
+	"github.com/golang/protobuf/proto"
 	cb "github.com/hyperledger/fabric/protos/common"
+	ab "github.com/hyperledger/fabric/protos/orderer"
 )
 
 var closedChan chan struct{}
@@ -27,7 +29,8 @@ func init() {
 	close(closedChan)
 }
 
-// NotFoundErrorIterator simply always returns an error of cb.Status_NOT_FOUND, and is generally useful for implementations of the Reader interface
+// NotFoundErrorIterator simply always returns an error of cb.Status_NOT_FOUND,
+// and is generally useful for implementations of the Reader interface
 type NotFoundErrorIterator struct{}
 
 // Next returns nil, cb.Status_NOT_FOUND
@@ -39,3 +42,64 @@ func (nfei *NotFoundErrorIterator) Next() (*cb.Block, cb.Status) {
 func (nfei *NotFoundErrorIterator) ReadyChan() <-chan struct{} {
 	return closedChan
 }
+
+// CreateNextBlock provides a utility way to construct the next block from
+// contents and metadata for a given ledger
+// XXX This will need to be modified to accept marshaled envelopes
+//     to accomodate non-deterministic marshaling
+func CreateNextBlock(rl Reader, messages []*cb.Envelope) *cb.Block {
+	var nextBlockNumber uint64
+	var previousBlockHash []byte
+
+	if rl.Height() > 0 {
+		it, _ := rl.Iterator(&ab.SeekPosition{
+			Type: &ab.SeekPosition_Newest{
+				&ab.SeekNewest{},
+			},
+		})
+		<-it.ReadyChan() // Should never block, but just in case
+		block, status := it.Next()
+		if status != cb.Status_SUCCESS {
+			panic("Error seeking to newest block for chain with non-zero height")
+		}
+		nextBlockNumber = block.Header.Number + 1
+		previousBlockHash = block.Header.Hash()
+	}
+
+	data := &cb.BlockData{
+		Data: make([][]byte, len(messages)),
+	}
+
+	var err error
+	for i, msg := range messages {
+		data.Data[i], err = proto.Marshal(msg)
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	block := cb.NewBlock(nextBlockNumber, previousBlockHash)
+	block.Header.DataHash = data.Hash()
+	block.Data = data
+
+	return block
+}
+
+// GetBlock is a utility method for retrieving a single block
+func GetBlock(rl Reader, index uint64) *cb.Block {
+	i, _ := rl.Iterator(&ab.SeekPosition{
+		Type: &ab.SeekPosition_Specified{
+			Specified: &ab.SeekSpecified{Number: index},
+		},
+	})
+	select {
+	case <-i.ReadyChan():
+		block, status := i.Next()
+		if status != cb.Status_SUCCESS {
+			return nil
+		}
+		return block
+	default:
+		return nil
+	}
+}