avoid empty chunk view

weed/filer2/filechunks.go

@@ -66,7 +66,7 @@ func ReadFromChunks(chunks []*filer_pb.FileChunk, offset int64, size int) (views
 	stop := offset + int64(size)
 
 	for _, chunk := range visibles {
-		if chunk.start <= offset && offset < chunk.stop {
+		if chunk.start <= offset && offset < chunk.stop && offset < stop {
 			views = append(views, &ChunkView{
 				FileId:      chunk.fileId,
 				Offset:      offset - chunk.start, // offset is the data starting location in this file id

weed/filer2/filechunks_test.go

@@ -249,6 +249,20 @@ func TestChunksReading(t *testing.T) {
 				{Offset: 0, Size: 100, FileId: "abc", LogicOffset:0},
 			},
 		},
+		// case 7: edge cases
+		{
+			Chunks: []*filer_pb.FileChunk{
+				{Offset: 0, Size: 100, FileId: "abc", Mtime: 123},
+				{Offset: 100, Size: 100, FileId: "asdf", Mtime: 134},
+				{Offset: 200, Size: 100, FileId: "fsad", Mtime: 353},
+			},
+			Offset: 0,
+			Size:   200,
+			Expected: []*ChunkView{
+				{Offset: 0, Size: 100, FileId: "abc", LogicOffset:0},
+				{Offset: 0, Size: 100, FileId: "asdf", LogicOffset:100},
+			},
+		},
 	}
 
 	for i, testcase := range testcases {