make ReadNeedleMeta a thin wrapperorigin/refactor-needle-read-operations

3 files changed, 51 insertions, 96 deletions

diff --git a/weed/storage/needle/needle_read_options.go b/weed/storage/needle/needle_read_options.go
index 77f0f26b8..3e1167aa0 100644
--- a/weed/storage/needle/needle_read_options.go
+++ b/weed/storage/needle/needle_read_options.go
@@ -1,6 +1,7 @@
 package needle
 
 import (
+	"fmt"
 	"io"
 
 	"github.com/seaweedfs/seaweedfs/weed/storage/backend"
@@ -18,7 +19,13 @@ type NeedleReadOptions struct {
 // ReadFromFile reads the Needle from the backend file according to the specified options.
 // - If only ReadHeader is true, only the header is read and parsed.
 // - If ReadData or ReadMeta is true, reads GetActualSize(size, version) bytes from disk (size is the logical body size).
-func (n *Needle) ReadFromFile(r backend.BackendStorageFile, offset int64, size Size, version Version, opts NeedleReadOptions) error {
+func (n *Needle) ReadFromFile(r backend.BackendStorageFile, offset int64, size Size, version Version, opts NeedleReadOptions) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("panic occurred: %+v", r)
+		}
+	}()
+
 	if opts.ReadHeader && !opts.ReadData && !opts.ReadMeta {
 		// Only read the header
 		header := make([]byte, NeedleHeaderSize)
@@ -33,63 +40,54 @@ func (n *Needle) ReadFromFile(r backend.BackendStorageFile, offset int64, size S
 		return nil
 	}
 	if opts.ReadHeader && opts.ReadMeta && !opts.ReadData {
-		// Read header first
-		header := make([]byte, NeedleHeaderSize)
-		count, err := r.ReadAt(header, offset)
-		if err == io.EOF && count == NeedleHeaderSize {
+		// Optimized: Read header and DataSize in one call
+		buf := make([]byte, NeedleHeaderSize+DataSizeSize)
+		count, err := r.ReadAt(buf, offset)
+		if err == io.EOF && count == NeedleHeaderSize+DataSizeSize {
 			err = nil
 		}
-		if count != NeedleHeaderSize || err != nil {
+		if count != NeedleHeaderSize+DataSizeSize || err != nil {
 			return err
 		}
-		n.ParseNeedleHeader(header)
+		n.ParseNeedleHeader(buf[:NeedleHeaderSize])
+		if n.Size != size {
+			if OffsetSize == 4 && offset < int64(MaxPossibleVolumeSize) {
+				return ErrorSizeMismatch
+			}
+		}
 
 		// Now read meta fields after DataSize+Data
-		metaOffset := offset + int64(NeedleHeaderSize)
-		metaIndex := 0
 		if version == Version2 || version == Version3 {
-			// Read DataSize to know how much to skip
-			dsBuf := make([]byte, 4)
-			count, err := r.ReadAt(dsBuf, metaOffset)
-			if err == io.EOF && count == 4 {
-				err = nil
-			}
-			if count != 4 || err != nil {
-				return err
+			n.DataSize = util.BytesToUint32(buf[NeedleHeaderSize : NeedleHeaderSize+DataSizeSize])
+
+			startOffset := offset + NeedleHeaderSize
+			if size.IsValid() {
+				startOffset = offset + NeedleHeaderSize + DataSizeSize + int64(n.DataSize)
 			}
-			dataSize := int(util.BytesToUint32(dsBuf))
-			metaIndex = 4 + dataSize
-			// Read meta fields (Flags, Name, Mime, etc.)
-			metaFieldsLen := int(n.Size) - dataSize // upper bound, may be more than needed
+			dataSize := GetActualSize(size, version)
+			stopOffset := offset + dataSize
+			metaFieldsLen := stopOffset - startOffset
+
 			metaFieldsBuf := make([]byte, metaFieldsLen)
-			count, err = r.ReadAt(metaFieldsBuf, metaOffset+int64(metaIndex))
-			if err == io.EOF && count == metaFieldsLen {
+			count, err = r.ReadAt(metaFieldsBuf, startOffset)
+			if err == io.EOF && int64(count) == metaFieldsLen {
 				err = nil
 			}
 			if count <= 0 || err != nil {
 				return err
 			}
-			_, err = n.readNeedleDataVersion2NonData(metaFieldsBuf)
-			if err != nil {
-				return err
-			}
-			// Now read checksum and (for v3) appendAtNs at the end
-			endMetaOffset := offset + int64(NeedleHeaderSize) + int64(n.Size)
-			endMetaLen := NeedleChecksumSize
-			if version == Version3 {
-				endMetaLen += TimestampSize
-			}
-			endMetaBuf := make([]byte, endMetaLen)
-			count, err = r.ReadAt(endMetaBuf, endMetaOffset)
-			if err == io.EOF && count == endMetaLen {
-				err = nil
-			}
-			if count != endMetaLen || err != nil {
-				return err
+
+			var index int
+			if size.IsValid() {
+				index, err = n.readNeedleDataVersion2NonData(metaFieldsBuf)
+				if err != nil {
+					return err
+				}
 			}
-			n.Checksum = CRC(util.BytesToUint32(endMetaBuf[:NeedleChecksumSize]))
+
+			n.Checksum = CRC(util.BytesToUint32(metaFieldsBuf[index : index+NeedleChecksumSize]))
 			if version == Version3 {
-				n.AppendAtNs = util.BytesToUint64(endMetaBuf[NeedleChecksumSize : NeedleChecksumSize+TimestampSize])
+				n.AppendAtNs = util.BytesToUint64(metaFieldsBuf[index+NeedleChecksumSize : index+NeedleChecksumSize+TimestampSize])
 			}
 			return nil
 		}
diff --git a/weed/storage/needle/needle_read_options_test.go b/weed/storage/needle/needle_read_options_test.go
index f86bab57a..03452b02a 100644
--- a/weed/storage/needle/needle_read_options_test.go
+++ b/weed/storage/needle/needle_read_options_test.go
@@ -150,6 +150,9 @@ func TestReadFromFile_OptionsMatrix(t *testing.T) {
 		if nMeta.Cookie != n.Cookie || nMeta.Id != n.Id || nMeta.Size != n.Size {
 			t.Errorf("header fields mismatch: got %+v want %+v", nMeta, n)
 		}
+		if nMeta.Checksum != n.Checksum {
+			t.Errorf("checksum mismatch: got %d want %d", nMeta.Checksum, n.Checksum)
+		}
 	})
 
 	t.Run("ReadHeader+ReadData", func(t *testing.T) {
diff --git a/weed/storage/needle/needle_read_page.go b/weed/storage/needle/needle_read_page.go
index 4e1032de8..fab52c8d9 100644
--- a/weed/storage/needle/needle_read_page.go
+++ b/weed/storage/needle/needle_read_page.go
@@ -1,12 +1,11 @@
 package needle
 
 import (
-	"fmt"
+	"io"
+
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/storage/backend"
 	. "github.com/seaweedfs/seaweedfs/weed/storage/types"
-	"github.com/seaweedfs/seaweedfs/weed/util"
-	"io"
 )
 
 // ReadNeedleData uses a needle without n.Data to read the content
@@ -33,57 +32,12 @@ func (n *Needle) ReadNeedleData(r backend.BackendStorageFile, volumeOffset int64
 }
 
 // ReadNeedleMeta fills all metadata except the n.Data
-func (n *Needle) ReadNeedleMeta(r backend.BackendStorageFile, offset int64, size Size, version Version) (err error) {
-	defer func() {
-		if r := recover(); r != nil {
-			err = fmt.Errorf("panic occurred: %+v", r)
-		}
-	}()
-
-	bytes := make([]byte, NeedleHeaderSize+DataSizeSize)
-
-	count, err := r.ReadAt(bytes, offset)
-	if err == io.EOF && count == NeedleHeaderSize+DataSizeSize {
-		err = nil
-	}
-	if count != NeedleHeaderSize+DataSizeSize || err != nil {
-		return err
-	}
-	n.ParseNeedleHeader(bytes)
-	if n.Size != size {
-		if OffsetSize == 4 && offset < int64(MaxPossibleVolumeSize) {
-			return ErrorSizeMismatch
-		}
-	}
-	n.DataSize = util.BytesToUint32(bytes[NeedleHeaderSize : NeedleHeaderSize+DataSizeSize])
-	startOffset := offset + NeedleHeaderSize
-	if size.IsValid() {
-		startOffset = offset + NeedleHeaderSize + DataSizeSize + int64(n.DataSize)
-	}
-	dataSize := GetActualSize(size, version)
-	stopOffset := offset + dataSize
-	metaSize := stopOffset - startOffset
-	metaSlice := make([]byte, int(metaSize))
-
-	count, err = r.ReadAt(metaSlice, startOffset)
-	if err != nil && int64(count) == metaSize {
-		err = nil
-	}
-	if err != nil {
-		return err
-	}
-
-	var index int
-	if size.IsValid() {
-		index, err = n.readNeedleDataVersion2NonData(metaSlice)
-	}
-
-	n.Checksum = CRC(util.BytesToUint32(metaSlice[index : index+NeedleChecksumSize]))
-	if version == Version3 {
-		n.AppendAtNs = util.BytesToUint64(metaSlice[index+NeedleChecksumSize : index+NeedleChecksumSize+TimestampSize])
-	}
-	return err
-
+func (n *Needle) ReadNeedleMeta(r backend.BackendStorageFile, offset int64, size Size, version Version) error {
+	return n.ReadFromFile(r, offset, size, version, NeedleReadOptions{
+		ReadHeader: true,
+		ReadMeta:   true,
+		ReadData:   false,
+	})
 }
 
 func min(x, y int64) int64 {