filer: skip resizing image if width or height larger than original image

fix https://github.com/chrislusf/seaweedfs/issues/1239#issuecomment-602140779

weed/filer2/stream.go

@@ -2,7 +2,6 @@ package filer2
 
 import (
 	"bytes"
-	"fmt"
 	"io"
 	"math"
 
@@ -48,9 +47,11 @@ type ChunkStreamReader struct {
 	masterClient *wdclient.MasterClient
 	chunkViews   []*ChunkView
 	logicOffset  int64
-	buffer       bytes.Buffer
+	buffer       []byte
 	bufferOffset int64
+	bufferPos    int
 	chunkIndex   int
+	totalSize    int64
 }
 
 var _ = io.ReadSeeker(&ChunkStreamReader{})
@@ -58,16 +59,21 @@ var _ = io.ReadSeeker(&ChunkStreamReader{})
 func NewChunkStreamReader(masterClient *wdclient.MasterClient, chunks []*filer_pb.FileChunk) *ChunkStreamReader {
 
 	chunkViews := ViewFromChunks(chunks, 0, math.MaxInt32)
+	var totalSize uint64
+	for _, chunk := range chunkViews {
+		totalSize += chunk.Size
+	}
 
 	return &ChunkStreamReader{
 		masterClient: masterClient,
 		chunkViews:   chunkViews,
 		bufferOffset: -1,
+		totalSize:    int64(totalSize),
 	}
 }
 
 func (c *ChunkStreamReader) Read(p []byte) (n int, err error) {
-	if c.buffer.Len() == 0 {
+	if c.isBufferEmpty() {
 		if c.chunkIndex >= len(c.chunkViews) {
 			return 0, io.EOF
 		}
@@ -75,11 +81,42 @@ func (c *ChunkStreamReader) Read(p []byte) (n int, err error) {
 		c.fetchChunkToBuffer(chunkView)
 		c.chunkIndex++
 	}
-	return c.buffer.Read(p)
+	n = copy(p, c.buffer[c.bufferPos:])
+	c.bufferPos += n
+	return
+}
+
+func (c *ChunkStreamReader) isBufferEmpty() bool {
+	return len(c.buffer) <= c.bufferPos
 }
 
 func (c *ChunkStreamReader) Seek(offset int64, whence int) (int64, error) {
-	return 0, fmt.Errorf("ChunkStreamReader: seek not supported")
+
+	var err error
+	switch whence {
+	case io.SeekStart:
+	case io.SeekCurrent:
+		offset += c.bufferOffset + int64(c.bufferPos)
+	case io.SeekEnd:
+		offset = c.totalSize + offset
+	}
+	if offset > c.totalSize {
+		err = io.ErrUnexpectedEOF
+	}
+
+	for i, chunk := range c.chunkViews {
+		if chunk.LogicOffset <= offset && offset < chunk.LogicOffset+int64(chunk.Size) {
+			if c.isBufferEmpty() || c.bufferOffset != offset {
+				c.fetchChunkToBuffer(chunk)
+				c.chunkIndex = i + 1
+				break
+			}
+		}
+	}
+	c.bufferPos = int(offset - c.bufferOffset)
+
+	return offset, err
+
 }
 
 func (c *ChunkStreamReader) fetchChunkToBuffer(chunkView *ChunkView) error {
@@ -88,13 +125,17 @@ func (c *ChunkStreamReader) fetchChunkToBuffer(chunkView *ChunkView) error {
 		glog.V(1).Infof("operation LookupFileId %s failed, err: %v", chunkView.FileId, err)
 		return err
 	}
-	c.buffer.Reset()
+	var buffer bytes.Buffer
 	err = util.ReadUrlAsStream(urlString, chunkView.CipherKey, chunkView.isGzipped, chunkView.IsFullChunk, chunkView.Offset, int(chunkView.Size), func(data []byte) {
-		c.buffer.Write(data)
+		buffer.Write(data)
 	})
 	if err != nil {
 		glog.V(1).Infof("read %s failed, err: %v", chunkView.FileId, err)
 		return err
 	}
+	c.buffer = buffer.Bytes()
+	c.bufferPos = 0
+	c.bufferOffset = chunkView.LogicOffset
+
 	return nil
 }

weed/images/resizing.go

@@ -6,10 +6,11 @@ import (
 	"image/gif"
 	"image/jpeg"
 	"image/png"
+	"io"
+
+	"github.com/disintegration/imaging"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/disintegration/imaging"
-	"io"
 )
 
 func Resized(ext string, read io.ReadSeeker, width, height int, mode string) (resized io.ReadSeeker, w int, h int) {
@@ -35,6 +36,7 @@ func Resized(ext string, read io.ReadSeeker, width, height int, mode string) (re
 				}
 			}
 		} else {
+			read.Seek(0, 0)
 			return read, bounds.Dx(), bounds.Dy()
 		}
 		var buf bytes.Buffer

weed/operation/chunked_file.go

@@ -142,11 +142,11 @@ func NewChunkedFileReader(chunkList []*ChunkInfo, master string) *ChunkedFileRea
 func (cf *ChunkedFileReader) Seek(offset int64, whence int) (int64, error) {
 	var err error
 	switch whence {
-	case 0:
-	case 1:
+	case io.SeekStart:
+	case io.SeekCurrent:
 		offset += cf.pos
-	case 2:
-		offset = cf.totalSize - offset
+	case io.SeekEnd:
+		offset = cf.totalSize + offset
 	}
 	if offset > cf.totalSize {
 		err = ErrInvalidRange