This closes #1903, made GetCellStyle, SetRowVisible and GetRowVisible functions concurrency safe

- Update comments of the functions and unit tests

cell_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	_ "image/jpeg"
 	"math"
+	"math/rand"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -42,6 +43,9 @@ func TestConcurrency(t *testing.T) {
 			assert.NoError(t, err)
 			// Concurrency set cell style
 			assert.NoError(t, f.SetCellStyle("Sheet1", "A3", "A3", style))
+			// Concurrency get cell style
+			_, err = f.GetCellStyle("Sheet1", "A3")
+			assert.NoError(t, err)
 			// Concurrency add picture
 			assert.NoError(t, f.AddPicture("Sheet1", "F21", filepath.Join("test", "images", "excel.jpg"),
 				&GraphicOptions{
@@ -87,7 +91,12 @@ func TestConcurrency(t *testing.T) {
 			// Concurrency get columns visible
 			visible, err := f.GetColVisible("Sheet1", "A")
 			assert.NoError(t, err)
-			assert.Equal(t, true, visible)
+			assert.True(t, visible)
+			// Concurrency set row visible
+			assert.NoError(t, f.SetRowVisible("Sheet1", 1+rand.Intn(1000), false))
+			// Concurrency get row visible
+			_, err = f.GetRowVisible("Sheet1", 1+rand.Intn(1000))
+			assert.NoError(t, err)
 			// Concurrency add data validation
 			dv := NewDataValidation(true)
 			dv.Sqref = fmt.Sprintf("A%d:B%d", val, val)

col.go

@@ -294,10 +294,13 @@ func (f *File) SetColVisible(sheet, columns string, visible bool) error {
 	if err != nil {
 		return err
 	}
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
 	ws.mu.Lock()
 	defer ws.mu.Unlock()
 	colData := xlsxCol{

rows.go

@@ -480,37 +480,46 @@ func (f *File) sharedStringsReader() (*xlsxSST, error) {
 }
 
 // SetRowVisible provides a function to set visible of a single row by given
-// worksheet name and Excel row number. For example, hide row 2 in Sheet1:
+// worksheet name and row number. This function is concurrency safe. For
+// example, hide row 2 in Sheet1:
 //
 //	err := f.SetRowVisible("Sheet1", 2, false)
 func (f *File) SetRowVisible(sheet string, row int, visible bool) error {
 	if row < 1 {
 		return newInvalidRowNumberError(row)
 	}
-
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	ws.prepareSheetXML(0, row)
 	ws.SheetData.Row[row-1].Hidden = !visible
 	return nil
 }
 
 // GetRowVisible provides a function to get visible of a single row by given
-// worksheet name and Excel row number. For example, get visible state of row
-// 2 in Sheet1:
+// worksheet name and row number. This function is concurrency safe. For
+// example, get visible state of row 2 in Sheet1:
 //
 //	visible, err := f.GetRowVisible("Sheet1", 2)
 func (f *File) GetRowVisible(sheet string, row int) (bool, error) {
 	if row < 1 {
 		return false, newInvalidRowNumberError(row)
 	}
-
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return false, err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	if row > len(ws.SheetData.Row) {
 		return false, nil
 	}

styles.go

@@ -2186,19 +2186,22 @@ func setCellXfs(style *xlsxStyleSheet, fontID, numFmtID, fillID, borderID int, a
 }
 
 // GetCellStyle provides a function to get cell style index by given worksheet
-// name and cell reference.
+// name and cell reference. This function is concurrency safe.
 func (f *File) GetCellStyle(sheet, cell string) (int, error) {
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return 0, err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	col, row, err := CellNameToCoordinates(cell)
 	if err != nil {
 		return 0, err
 	}
 	ws.prepareSheetXML(col, row)
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	return ws.prepareCellStyle(col, row, ws.SheetData.Row[row-1].C[col-1].S), err
 }