address comment

pkg/streamer/file.go

@@ -43,6 +43,12 @@ const (
 	FileCmpBigger
 )
 
+// SwitchPath represents next binlog file path which should be switched
+type SwitchPath struct {
+	nextUUID       string
+	nextBinlogName string
+}
+
 // CollectAllBinlogFiles collects all valid binlog files in dir
 func CollectAllBinlogFiles(dir string) ([]string, error) {
 	if dir == "" {
@@ -311,10 +317,7 @@ func relaySubDirUpdated(ctx context.Context, watcherInterval time.Duration, dir
 }
 
 // needSwitchSubDir checks whether the reader need to switch to next relay sub directory
-func needSwitchSubDir(ctx context.Context, relayDir, currentUUID, latestFilePath string, latestFileSize int64, switchCh chan struct {
-	nextUUID       string
-	nextBinlogName string
-}, errCh chan error) {
+func needSwitchSubDir(ctx context.Context, relayDir, currentUUID, latestFilePath string, latestFileSize int64, switchCh chan SwitchPath, errCh chan error) {
 	var (
 		err            error
 		nextUUID       string
@@ -359,10 +362,7 @@ func needSwitchSubDir(ctx context.Context, relayDir, currentUUID, latestFilePath
 				return
 			}
 
-			switchCh <- struct {
-				nextUUID       string
-				nextBinlogName string
-			}{nextUUID, nextBinlogName}
+			switchCh <- SwitchPath{nextUUID, nextBinlogName}
 			return
 		}
 	}

pkg/streamer/file_test.go

@@ -472,11 +472,8 @@ func (t *testFileSuite) TestNeedSwitchSubDir(c *C) {
 		latestFilePath string
 		latestFileSize int64
 		data           = []byte("binlog file data")
-		switchCh       = make(chan struct {
-			nextUUID       string
-			nextBinlogName string
-		}, 1)
-		errCh = make(chan error, 1)
+		switchCh       = make(chan SwitchPath, 1)
+		errCh          = make(chan error, 1)
 	)
 
 	ctx := context.Background()

pkg/streamer/reader.go

@@ -605,10 +605,7 @@ func (r *BinlogReader) parseFile(
 		return false, false, latestPos, "", "", nil
 	}
 
-	switchCh := make(chan struct {
-		nextUUID       string
-		nextBinlogName string
-	}, 1)
+	switchCh := make(chan SwitchPath, 1)
 	switchErrCh := make(chan error, 1)
 	updatePathCh := make(chan string, 1)
 	updateErrCh := make(chan error, 1)