remove proto 1 and 2 support

You can't find servers that support only proto 1 or 2.
And there is no technical benefits to restrict proto to these versions.
So, we can easily remove code that is taking care of these versions.

Patch by dkropachev; reviewed by joao-r-reis for CASSGO-75

Author: dkropachev

batch_test.go

@@ -40,10 +40,6 @@ func TestBatch_Errors(t *testing.T) {
 	session := createSession(t)
 	defer session.Close()
 
-	if session.cfg.ProtoVersion < protoVersion2 {
-		t.Skip("atomic batches not supported. Please use Cassandra >= 2.0")
-	}
-
 	if err := createTable(session, `CREATE TABLE gocql_test.batch_errors (id int primary key, val inet)`); err != nil {
 		t.Fatal(err)
 	}
@@ -59,10 +55,6 @@ func TestBatch_WithTimestamp(t *testing.T) {
 	session := createSession(t)
 	defer session.Close()
 
-	if session.cfg.ProtoVersion < protoVersion3 {
-		t.Skip("Batch timestamps are only available on protocol >= 3")
-	}
-
 	if err := createTable(session, `CREATE TABLE gocql_test.batch_ts (id int primary key, val text)`); err != nil {
 		t.Fatal(err)
 	}

cassandra_test.go

@@ -2284,25 +2284,7 @@ func TestGetTableMetadata(t *testing.T) {
 	if testTable == nil {
 		t.Fatal("Expected table metadata for name 'test_table_metadata'")
 	}
-	if session.cfg.ProtoVersion == protoVersion1 {
-		if testTable.KeyValidator != "org.apache.cassandra.db.marshal.Int32Type" {
-			t.Errorf("Expected test_table_metadata key validator to be 'org.apache.cassandra.db.marshal.Int32Type' but was '%s'", testTable.KeyValidator)
-		}
-		if testTable.Comparator != "org.apache.cassandra.db.marshal.CompositeType(org.apache.cassandra.db.marshal.Int32Type,org.apache.cassandra.db.marshal.UTF8Type)" {
-			t.Errorf("Expected test_table_metadata key validator to be 'org.apache.cassandra.db.marshal.CompositeType(org.apache.cassandra.db.marshal.Int32Type,org.apache.cassandra.db.marshal.UTF8Type)' but was '%s'", testTable.Comparator)
-		}
-		if testTable.DefaultValidator != "org.apache.cassandra.db.marshal.BytesType" {
-			t.Errorf("Expected test_table_metadata key validator to be 'org.apache.cassandra.db.marshal.BytesType' but was '%s'", testTable.DefaultValidator)
-		}
-		expectedKeyAliases := []string{"first_id"}
-		if !reflect.DeepEqual(testTable.KeyAliases, expectedKeyAliases) {
-			t.Errorf("Expected key aliases %v but was %v", expectedKeyAliases, testTable.KeyAliases)
-		}
-		expectedColumnAliases := []string{"second_id"}
-		if !reflect.DeepEqual(testTable.ColumnAliases, expectedColumnAliases) {
-			t.Errorf("Expected key aliases %v but was %v", expectedColumnAliases, testTable.ColumnAliases)
-		}
-	}
+
 	if testTable.ValueAlias != "" {
 		t.Errorf("Expected value alias '' but was '%s'", testTable.ValueAlias)
 	}
@@ -3228,10 +3210,6 @@ func TestUnmarshallNestedTypes(t *testing.T) {
 	session := createSession(t)
 	defer session.Close()
 
-	if session.cfg.ProtoVersion < protoVersion3 {
-		t.Skip("can not have frozen types in cassandra < 2.1.3")
-	}
-
 	if err := createTable(session, `CREATE TABLE gocql_test.test_557 (
 		    id text PRIMARY KEY,
 		    val list<frozen<map<text, text> > >

conn.go

@@ -179,7 +179,7 @@ type Conn struct {
 	frameObserver  FrameHeaderObserver
 	streamObserver StreamObserver
 
-	headerBuf [maxFrameHeaderSize]byte
+	headerBuf [frameHeadSize]byte
 
 	streams *streams.IDGenerator
 	mu      sync.Mutex
@@ -784,12 +784,11 @@ func (c *Conn) recvSegment(ctx context.Context) error {
 		return err
 	}
 
-	const frameHeaderLength = 9
-	buf := bytes.NewBuffer(make([]byte, 0, head.length+frameHeaderLength))
+	buf := bytes.NewBuffer(make([]byte, 0, head.length+frameHeadSize))
 	buf.Write(frame)
 
 	// Computing how many bytes of message left to read
-	bytesToRead := head.length - len(frame) + frameHeaderLength
+	bytesToRead := head.length - len(frame) + frameHeadSize
 
 	err = c.recvPartialFrames(buf, bytesToRead)
 	if err != nil {
@@ -1738,10 +1737,6 @@ func (c *Conn) UseKeyspace(keyspace string) error {
 }
 
 func (c *Conn) executeBatch(ctx context.Context, batch *Batch) *Iter {
-	if c.version == protoVersion1 {
-		return &Iter{err: ErrUnsupported}
-	}
-
 	n := len(batch.Entries)
 	req := &writeBatchFrame{
 		typ:                   batch.Type,

conn_test.go

@@ -53,7 +53,7 @@ import (
 )
 
 const (
-	defaultProto = protoVersion2
+	defaultProto = protoVersion4
 )
 
 func TestApprove(t *testing.T) {
@@ -1056,18 +1056,13 @@ func (nts newTestServerOpts) newServer(t testing.TB, ctx context.Context) *TestS
 		t.Fatal(err)
 	}
 
-	headerSize := 8
-	if nts.protocol > protoVersion2 {
-		headerSize = 9
-	}
-
 	ctx, cancel := context.WithCancel(ctx)
 	srv := &TestServer{
 		Address:    listen.Addr().String(),
 		listen:     listen,
 		t:          t,
 		protocol:   nts.protocol,
-		headerSize: headerSize,
+		headerSize: 9,
 		ctx:        ctx,
 		cancel:     cancel,
 
@@ -1103,18 +1098,13 @@ func NewSSLTestServer(t testing.TB, protocol uint8, ctx context.Context) *TestSe
 		t.Fatal(err)
 	}
 
-	headerSize := 8
-	if protocol > protoVersion2 {
-		headerSize = 9
-	}
-
 	ctx, cancel := context.WithCancel(ctx)
 	srv := &TestServer{
 		Address:    listen.Addr().String(),
 		listen:     listen,
 		t:          t,
 		protocol:   protocol,
-		headerSize: headerSize,
+		headerSize: 9,
 		ctx:        ctx,
 		cancel:     cancel,
 	}