This closes #833, closes #845, and closes #1022, breaking changes

- Close spreadsheet and row's iterator required
- New options `WorksheetUnzipMemLimit` have been added
- Improve streaming reading performance, memory usage decrease about 93.7%

.gitignore

@@ -5,6 +5,7 @@ test/Test*.xlsm
 test/BadEncrypt.xlsx
 test/BadWorkbook.SaveAsEmptyStruct.xlsx
 test/*.png
+test/excelize-*
 *.out
 *.test
 .idea

README.md

@@ -96,6 +96,10 @@ func main() {
         }
         fmt.Println()
     }
+    // Close the spreadsheet.
+    if err = f.Close(); err != nil {
+        fmt.Println(err)
+    }
 }
 ```
 
@@ -203,6 +207,10 @@ func main() {
     if err = f.Save(); err != nil {
         fmt.Println(err)
     }
+    // Close the spreadsheet.
+    if err = f.Close(); err != nil {
+        fmt.Println(err)
+    }
 }
 ```
 

README_zh.md

@@ -96,6 +96,10 @@ func main() {
         }
         fmt.Println()
     }
+    // 关闭工作簿
+    if err = f.Close(); err != nil {
+        fmt.Println(err)
+    }
 }
 ```
 
@@ -199,10 +203,14 @@ func main() {
     }`); err != nil {
         fmt.Println(err)
     }
-    // 保存文件
+    // 保存工作簿
     if err = f.Save(); err != nil {
         fmt.Println(err)
     }
+    // 关闭工作簿
+    if err = f.Close(); err != nil {
+        fmt.Println(err)
+    }
 }
 ```
 

cell_test.go

@@ -72,6 +72,7 @@ func TestConcurrency(t *testing.T) {
 	}
 	assert.Equal(t, "1", val)
 	assert.NoError(t, f.SaveAs(filepath.Join("test", "TestConcurrency.xlsx")))
+	assert.NoError(t, f.Close())
 }
 
 func TestCheckCellInArea(t *testing.T) {
@@ -325,6 +326,7 @@ func TestOverflowNumericCell(t *testing.T) {
 	assert.NoError(t, err)
 	// GOARCH=amd64 - all ok; GOARCH=386 - actual: "-2147483648"
 	assert.Equal(t, "8595602512225", val, "A1 should be 8595602512225")
+	assert.NoError(t, f.Close())
 }
 
 func TestSetCellFormula(t *testing.T) {
@@ -340,6 +342,7 @@ func TestSetCellFormula(t *testing.T) {
 	assert.EqualError(t, f.SetCellFormula("Sheet1", "C", "SUM(Sheet2!D2,Sheet2!D9)"), `cannot convert cell "C" to coordinates: invalid cell name "C"`)
 
 	assert.NoError(t, f.SaveAs(filepath.Join("test", "TestSetCellFormula1.xlsx")))
+	assert.NoError(t, f.Close())
 
 	f, err = OpenFile(filepath.Join("test", "CalcChain.xlsx"))
 	if !assert.NoError(t, err) {
@@ -351,6 +354,7 @@ func TestSetCellFormula(t *testing.T) {
 	// Test remove all cell formula.
 	assert.NoError(t, f.SetCellFormula("Sheet1", "B1", ""))
 	assert.NoError(t, f.SaveAs(filepath.Join("test", "TestSetCellFormula3.xlsx")))
+	assert.NoError(t, f.Close())
 
 	// Test set shared formula for the cells.
 	f = NewFile()

chart_test.go

@@ -206,6 +206,7 @@ func TestAddChart(t *testing.T) {
 	assert.EqualError(t, f.AddChart("Sheet2", "BD32", `{"type":"col","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$30:$D$30"},{"name":"Sheet1!$A$31","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$31:$D$31"},{"name":"Sheet1!$A$32","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$32:$D$32"},{"name":"Sheet1!$A$33","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$33:$D$33"},{"name":"Sheet1!$A$34","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$34:$D$34"},{"name":"Sheet1!$A$35","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$35:$D$35"},{"name":"Sheet1!$A$36","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$36:$D$36"},{"name":"Sheet1!$A$37","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$37:$D$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"left","show_legend_key":false},"title":{"name":"2D Column Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero"}`, ""), "unexpected end of JSON input")
 	// Test add combo chart with unsupported chart type
 	assert.EqualError(t, f.AddChart("Sheet2", "BD64", `{"type":"barOfPie","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$A$30:$D$37","values":"Sheet1!$B$30:$B$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"left","show_legend_key":false},"title":{"name":"Bar of Pie Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero","x_axis":{"major_grid_lines":true},"y_axis":{"major_grid_lines":true}}`, `{"type":"unknown","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$A$30:$D$37","values":"Sheet1!$B$30:$B$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"left","show_legend_key":false},"title":{"name":"Bar of Pie Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero","x_axis":{"major_grid_lines":true},"y_axis":{"major_grid_lines":true}}`), "unsupported chart type unknown")
+	assert.NoError(t, f.Close())
 }
 
 func TestAddChartSheet(t *testing.T) {
@@ -254,6 +255,7 @@ func TestDeleteChart(t *testing.T) {
 	assert.EqualError(t, f.DeleteChart("Sheet1", ""), `cannot convert cell "" to coordinates: invalid cell name ""`)
 	// Test delete chart on no chart worksheet.
 	assert.NoError(t, NewFile().DeleteChart("Sheet1", "A1"))
+	assert.NoError(t, f.Close())
 }
 
 func TestChartWithLogarithmicBase(t *testing.T) {

col.go

@@ -209,7 +209,7 @@ func (f *File) Cols(sheet string) (*Cols, error) {
 		f.saveFileList(name, f.replaceNameSpaceBytes(name, output))
 	}
 	var colIterator columnXMLIterator
-	colIterator.cols.sheetXML = f.readXML(name)
+	colIterator.cols.sheetXML = f.readBytes(name)
 	decoder := f.xmlNewDecoder(bytes.NewReader(colIterator.cols.sheetXML))
 	for {
 		token, _ := decoder.Token()

col_test.go

@@ -39,6 +39,7 @@ func TestCols(t *testing.T) {
 	if !assert.Equal(t, collectedRows, returnedColumns) {
 		t.FailNow()
 	}
+	assert.NoError(t, f.Close())
 
 	f = NewFile()
 	cells := []string{"C2", "C3", "C4"}
@@ -75,6 +76,7 @@ func TestColumnsIterator(t *testing.T) {
 		require.True(t, colCount <= expectedNumCol, "colCount is greater than expected")
 	}
 	assert.Equal(t, expectedNumCol, colCount)
+	assert.NoError(t, f.Close())
 
 	f = NewFile()
 	cells := []string{"C2", "C3", "C4", "D2", "D3", "D4"}
@@ -99,6 +101,7 @@ func TestColsError(t *testing.T) {
 	}
 	_, err = f.Cols("SheetN")
 	assert.EqualError(t, err, "sheet SheetN is not exist")
+	assert.NoError(t, f.Close())
 }
 
 func TestGetColsError(t *testing.T) {
@@ -108,6 +111,7 @@ func TestGetColsError(t *testing.T) {
 	}
 	_, err = f.GetCols("SheetN")
 	assert.EqualError(t, err, "sheet SheetN is not exist")
+	assert.NoError(t, f.Close())
 
 	f = NewFile()
 	f.Sheet.Delete("xl/worksheets/sheet1.xml")
@@ -283,6 +287,7 @@ func TestOutlineLevel(t *testing.T) {
 	f, err = OpenFile(filepath.Join("test", "Book1.xlsx"))
 	assert.NoError(t, err)
 	assert.NoError(t, f.SetColOutlineLevel("Sheet2", "B", 2))
+	assert.NoError(t, f.Close())
 }
 
 func TestSetColStyle(t *testing.T) {

crypt_test.go

@@ -22,6 +22,7 @@ func TestEncrypt(t *testing.T) {
 	f, err := OpenFile(filepath.Join("test", "encryptSHA1.xlsx"), Options{Password: "password"})
 	assert.NoError(t, err)
 	assert.EqualError(t, f.SaveAs(filepath.Join("test", "BadEncrypt.xlsx"), Options{Password: "password"}), "not support encryption currently")
+	assert.NoError(t, f.Close())
 }
 
 func TestEncryptionMechanism(t *testing.T) {

docProps_test.go

@@ -44,6 +44,7 @@ func TestSetDocProps(t *testing.T) {
 	assert.NoError(t, f.SaveAs(filepath.Join("test", "TestSetDocProps.xlsx")))
 	f.Pkg.Store("docProps/core.xml", nil)
 	assert.NoError(t, f.SetDocProps(&DocProperties{}))
+	assert.NoError(t, f.Close())
 
 	// Test unsupported charset
 	f = NewFile()
@@ -62,6 +63,7 @@ func TestGetDocProps(t *testing.T) {
 	f.Pkg.Store("docProps/core.xml", nil)
 	_, err = f.GetDocProps()
 	assert.NoError(t, err)
+	assert.NoError(t, f.Close())
 
 	// Test unsupported charset
 	f = NewFile()

errors.go

@@ -131,4 +131,7 @@ var (
 	// ErrCellCharsLength defined the error message for receiving a cell
 	// characters length that exceeds the limit.
 	ErrCellCharsLength = fmt.Errorf("cell value must be 0-%d characters", TotalCellChars)
+	// ErrOptionsUnzipSizeLimit defined the error message for receiving
+	// invalid UnzipSizeLimit and WorksheetUnzipMemLimit.
+	ErrOptionsUnzipSizeLimit = errors.New("the value of UnzipSizeLimit should be greater than or equal to WorksheetUnzipMemLimit")
 )

excelize.go

@@ -37,6 +37,7 @@ type File struct {
 	checked          map[string]bool
 	sheetMap         map[string]string
 	streams          map[string]*StreamWriter
+	tempFiles        sync.Map
 	CalcChain        *xlsxCalcChain
 	Comments         map[string]*xlsxComments
 	ContentTypes     *xlsxTypes
@@ -58,13 +59,26 @@ type File struct {
 
 type charsetTranscoderFn func(charset string, input io.Reader) (rdr io.Reader, err error)
 
-// Options define the options for open and reading spreadsheet. RawCellValue
-// specify if apply the number format for the cell value or get the raw
-// value.
+// Options define the options for open and reading spreadsheet.
+//
+// Password specifies the password of the spreadsheet in plain text.
+//
+// RawCellValue specifies if apply the number format for the cell value or get
+// the raw value.
+//
+// UnzipSizeLimit specifies the unzip size limit in bytes on open the
+// spreadsheet, this value should be greater than or equal to
+// WorksheetUnzipMemLimit, the default size limit is 16GB.
+//
+// WorksheetUnzipMemLimit specifies the memory limit on unzipping worksheet in
+// bytes, worksheet XML will be extracted to system temporary directory when
+// the file size is over this value, this value should be less than or equal
+// to UnzipSizeLimit, the default value is 16MB.
 type Options struct {
-	Password       string
-	RawCellValue   bool
-	UnzipSizeLimit int64
+	Password               string
+	RawCellValue           bool
+	UnzipSizeLimit         int64
+	WorksheetUnzipMemLimit int64
 }
 
 // OpenFile take the name of an spreadsheet file and returns a populated
@@ -78,10 +92,8 @@ type Options struct {
 //
 // Note that the excelize just support decrypt and not support encrypt
 // currently, the spreadsheet saved by Save and SaveAs will be without
-// password unprotected.
-//
-// UnzipSizeLimit specified the unzip size limit in bytes on open the
-// spreadsheet, the default size limit is 16GB.
+// password unprotected. Close the file by Close after opening the
+// spreadsheet.
 func OpenFile(filename string, opt ...Options) (*File, error) {
 	file, err := os.Open(filepath.Clean(filename))
 	if err != nil {
@@ -99,10 +111,11 @@ func OpenFile(filename string, opt ...Options) (*File, error) {
 // newFile is object builder
 func newFile() *File {
 	return &File{
-		options:          &Options{UnzipSizeLimit: UnzipSizeLimit},
+		options:          &Options{UnzipSizeLimit: UnzipSizeLimit, WorksheetUnzipMemLimit: StreamChunkSize},
 		xmlAttr:          make(map[string][]xml.Attr),
 		checked:          make(map[string]bool),
 		sheetMap:         make(map[string]string),
+		tempFiles:        sync.Map{},
 		Comments:         make(map[string]*xlsxComments),
 		Drawings:         sync.Map{},
 		sharedStringsMap: make(map[string]int),
@@ -125,6 +138,18 @@ func OpenReader(r io.Reader, opt ...Options) (*File, error) {
 	f.options = parseOptions(opt...)
 	if f.options.UnzipSizeLimit == 0 {
 		f.options.UnzipSizeLimit = UnzipSizeLimit
+		if f.options.WorksheetUnzipMemLimit > f.options.UnzipSizeLimit {
+			f.options.UnzipSizeLimit = f.options.WorksheetUnzipMemLimit
+		}
+	}
+	if f.options.WorksheetUnzipMemLimit == 0 {
+		f.options.WorksheetUnzipMemLimit = StreamChunkSize
+		if f.options.UnzipSizeLimit < f.options.WorksheetUnzipMemLimit {
+			f.options.WorksheetUnzipMemLimit = f.options.UnzipSizeLimit
+		}
+	}
+	if f.options.WorksheetUnzipMemLimit > f.options.UnzipSizeLimit {
+		return nil, ErrOptionsUnzipSizeLimit
 	}
 	if bytes.Contains(b, oleIdentifier) {
 		b, err = Decrypt(b, f.options)
@@ -136,7 +161,7 @@ func OpenReader(r io.Reader, opt ...Options) (*File, error) {
 	if err != nil {
 		return nil, err
 	}
-	file, sheetCount, err := ReadZipReader(zr, f.options)
+	file, sheetCount, err := f.ReadZipReader(zr)
 	if err != nil {
 		return nil, err
 	}
@@ -210,10 +235,10 @@ func (f *File) workSheetReader(sheet string) (ws *xlsxWorksheet, err error) {
 	}
 	ws = new(xlsxWorksheet)
 	if _, ok := f.xmlAttr[name]; !ok {
-		d := f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readXML(name))))
+		d := f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readBytes(name))))
 		f.xmlAttr[name] = append(f.xmlAttr[name], getRootElement(d)...)
 	}
-	if err = f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readXML(name)))).
+	if err = f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readBytes(name)))).
 		Decode(ws); err != nil && err != io.EOF {
 		err = fmt.Errorf("xml decode error: %s", err)
 		return