From 4c7eaf9ef4e4b6df835fcd939d1325f86b2801b6 Mon Sep 17 00:00:00 2001
From: Chunzhu Li <lichunzhu@stu.xjtu.edu.cn>
Date: Fri, 18 Nov 2022 17:42:09 +0800
Subject: [PATCH] address comment

---
 br/pkg/lightning/restore/get_pre_info.go | 36 ++----------------------
 br/pkg/lightning/restore/restore.go      | 35 ++++++++++++-----------
 2 files changed, 20 insertions(+), 51 deletions(-)

diff --git a/br/pkg/lightning/restore/get_pre_info.go b/br/pkg/lightning/restore/get_pre_info.go
index f1075d43c042c..93927c6956809 100644
--- a/br/pkg/lightning/restore/get_pre_info.go
+++ b/br/pkg/lightning/restore/get_pre_info.go
@@ -444,23 +444,7 @@ func (p *PreRestoreInfoGetterImpl) ReadFirstNRowsByTableName(ctx context.Context
 // ReadFirstNRowsByFileMeta reads the first N rows of an data file.
 // It implements the PreRestoreInfoGetter interface.
 func (p *PreRestoreInfoGetterImpl) ReadFirstNRowsByFileMeta(ctx context.Context, dataFileMeta mydump.SourceFileMeta, n int) ([]string, [][]types.Datum, error) {
-	var (
-		reader storage.ReadSeekCloser
-		err    error
-	)
-	switch {
-	case dataFileMeta.Type == mydump.SourceTypeParquet:
-		reader, err = mydump.OpenParquetReader(ctx, p.srcStorage, dataFileMeta.Path, dataFileMeta.FileSize)
-	case dataFileMeta.Compression != mydump.CompressionNone:
-		var compressType storage.CompressType
-		compressType, err = mydump.ToStorageCompressType(dataFileMeta.Compression)
-		if err != nil {
-			break
-		}
-		reader, err = storage.WithCompression(p.srcStorage, compressType).Open(ctx, dataFileMeta.Path)
-	default:
-		reader, err = p.srcStorage.Open(ctx, dataFileMeta.Path)
-	}
+	reader, err := openReader(ctx, dataFileMeta, p.srcStorage)
 	if err != nil {
 		return nil, nil, errors.Trace(err)
 	}
@@ -598,23 +582,7 @@ func (p *PreRestoreInfoGetterImpl) sampleDataFromTable(
 		return resultIndexRatio, isRowOrdered, nil
 	}
 	sampleFile := tableMeta.DataFiles[0].FileMeta
-	var (
-		reader storage.ReadSeekCloser
-		err    error
-	)
-	switch {
-	case sampleFile.Type == mydump.SourceTypeParquet:
-		reader, err = mydump.OpenParquetReader(ctx, p.srcStorage, sampleFile.Path, sampleFile.FileSize)
-	case sampleFile.Compression != mydump.CompressionNone:
-		var compressType storage.CompressType
-		compressType, err = mydump.ToStorageCompressType(sampleFile.Compression)
-		if err != nil {
-			break
-		}
-		reader, err = storage.WithCompression(p.srcStorage, compressType).Open(ctx, sampleFile.Path)
-	default:
-		reader, err = p.srcStorage.Open(ctx, sampleFile.Path)
-	}
+	reader, err := openReader(ctx, sampleFile, p.srcStorage)
 	if err != nil {
 		return 0.0, false, errors.Trace(err)
 	}
diff --git a/br/pkg/lightning/restore/restore.go b/br/pkg/lightning/restore/restore.go
index 0a0e05b45ac5d..d7a4fd0d3cc8b 100644
--- a/br/pkg/lightning/restore/restore.go
+++ b/br/pkg/lightning/restore/restore.go
@@ -2190,23 +2190,7 @@ func newChunkRestore(
 ) (*chunkRestore, error) {
 	blockBufSize := int64(cfg.Mydumper.ReadBlockSize)
 
-	var (
-		reader       storage.ReadSeekCloser
-		compressType storage.CompressType
-		err          error
-	)
-	switch {
-	case chunk.FileMeta.Type == mydump.SourceTypeParquet:
-		reader, err = mydump.OpenParquetReader(ctx, store, chunk.FileMeta.Path, chunk.FileMeta.FileSize)
-	case chunk.FileMeta.Compression != mydump.CompressionNone:
-		compressType, err = mydump.ToStorageCompressType(chunk.FileMeta.Compression)
-		if err != nil {
-			break
-		}
-		reader, err = storage.WithCompression(store, compressType).Open(ctx, chunk.FileMeta.Path)
-	default:
-		reader, err = store.Open(ctx, chunk.FileMeta.Path)
-	}
+	reader, err := openReader(ctx, chunk.FileMeta, store)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
@@ -2771,3 +2755,20 @@ func (cr *chunkRestore) restore(
 	}
 	return errors.Trace(firstErr(encodeErr, deliverErr))
 }
+
+func openReader(ctx context.Context, fileMeta mydump.SourceFileMeta, store storage.ExternalStorage) (
+	reader storage.ReadSeekCloser, err error) {
+	switch {
+	case fileMeta.Type == mydump.SourceTypeParquet:
+		reader, err = mydump.OpenParquetReader(ctx, store, fileMeta.Path, fileMeta.FileSize)
+	case fileMeta.Compression != mydump.CompressionNone:
+		compressType, err2 := mydump.ToStorageCompressType(fileMeta.Compression)
+		if err2 != nil {
+			return nil, err2
+		}
+		reader, err = storage.WithCompression(store, compressType).Open(ctx, fileMeta.Path)
+	default:
+		reader, err = store.Open(ctx, fileMeta.Path)
+	}
+	return
+}