Go exceed API source code reading (V) -- close (), newsheet ()

Go-Excelize API Source code reading （ 5、 ... and ）—— Close()

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One 、Go-Excelize brief introduction

Excelize yes Go Language written for operation Office Excel Document base library , be based on ECMA-376,ISO/IEC 29500 international standard . You can use it to read 、 Written by Microsoft Excel 2007 Spreadsheet documents created by and above . Support XLAM / XLSM / XLSX / XLTM / XLTX And so on , Highly compatible with styles 、 picture ( surface )、 PivotTable 、 Slicer and other complex components of the document , And provide streaming reading and writing API, For workbooks that contain large amounts of data . It can be applied to various report platforms 、 Cloud computing 、 Edge computing and other systems . Required to use this class library Go The language is 1.15 Or later .

Two 、Close()

func (f *File) Close() error

this API The function of is to close the workbook and clean up the system disk cache that may be generated when opening the document .

Let's take a look at the specific code ：

func (f *File) Close() error {
    
	var err error
	if f.sharedStringTemp != nil {
    
		if err := f.sharedStringTemp.Close(); err != nil {
    
			return err
		}
	}
	f.tempFiles.Range(func(k, v interface{
    }) bool {
    
		if err = os.Remove(v.(string)); err != nil {
    
			return false
		}
		return true
	})
	return err
}

First judge sharedStringTemp Is it empty , This is a *os.File Variable of type . It should be to close an important cache file .

The next step is to traverse the temporary file ,os.Remove(v.(string)) These temporary files and folders will be deleted .
The above steps have cleared the system disk cache that may be generated when opening documents .

3、 ... and 、NewSheet()

func (f *File) NewSheet(sheet string) int

The API The function of is to create a new worksheet according to the given worksheet name , And return the index of the worksheet in the workbook . Please note that , When creating a new workbook , Will contain a file named Sheet1 Default worksheet for .

func (f *File) NewSheet(name string) int {
    
	// Check if the worksheet already exists
	index := f.GetSheetIndex(name)
	if index != -1 {
    
		return index
	}
	f.DeleteSheet(name)
	f.SheetCount++
	wb := f.workbookReader()
	sheetID := 0
	for _, v := range wb.Sheets.Sheet {
    
		if v.SheetID > sheetID {
    
			sheetID = v.SheetID
		}
	}
	sheetID++
	// Update docProps/app.xml
	f.setAppXML()
	// Update [Content_Types].xml
	f.setContentTypes("/xl/worksheets/sheet"+strconv.Itoa(sheetID)+".xml", ContentTypeSpreadSheetMLWorksheet)
	// Create new sheet /xl/worksheets/sheet%d.xml
	f.setSheet(sheetID, name)
	// Update workbook.xml.rels
	rID := f.addRels(f.getWorkbookRelsPath(), SourceRelationshipWorkSheet, fmt.Sprintf("/xl/worksheets/sheet%d.xml", sheetID), "")
	// Update workbook.xml
	f.setWorkbook(name, sheetID, rID)
	return f.GetSheetIndex(name)
}

Please note that , Worksheet names are case insensitive .

First check whether the payroll with the given name exists , If it doesn't exist GetSheetIndex It will return -1, Otherwise, return to the worksheet index .

func (f *File) GetSheetIndex(name string) int {
    
	for index, sheet := range f.GetSheetList() {
    
		if strings.EqualFold(sheet, trimSheetName(name)) {
    
			return index
		}
	}
	return -1
}

If GetSheetIndex It will return -1, That is, the worksheet exists , Just call DeleteSheet Delete this worksheet .
And then build a wb := f.workbookReader() Workbook reader .

for _, v := range wb.Sheets.Sheet {
    
		if v.SheetID > sheetID {
    
			sheetID = v.SheetID
		}
	}

The meaning of this code should be to find the maximum of the worksheet SheetID , Assign a value to sheetID.
Then create or update docProps/app.xml、[Content_Types].xml、/xl/worksheets/sheet%d.xml、 workbook.xml.rels、workbook.xml These documents .

	// Update docProps/app.xml
	f.setAppXML()
	// Update [Content_Types].xml
	f.setContentTypes("/xl/worksheets/sheet"+strconv.Itoa(sheetID)+".xml", ContentTypeSpreadSheetMLWorksheet)
	// Create new sheet /xl/worksheets/sheet%d.xml
	f.setSheet(sheetID, name)
	// Update workbook.xml.rels
	rID := f.addRels(f.getWorkbookRelsPath(), SourceRelationshipWorkSheet, fmt.Sprintf("/xl/worksheets/sheet%d.xml", sheetID), "")
	// Update workbook.xml
	f.setWorkbook(name, sheetID, rID)

Finally return to this Sheet.

3、 ... and 、 Conclusion
This is Lao Yue , This is a Go Interpretation of language related source code Chapter 5 , I'll keep trying , Bring you more similar articles , Please give me your advice .