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Diffstat (limited to 'stream.go')
| -rw-r--r-- | stream.go | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/stream.go b/stream.go new file mode 100644 index 0000000..0d91ddd --- /dev/null +++ b/stream.go @@ -0,0 +1,219 @@ +// Copyright 2016 - 2019 The excelize Authors. All rights reserved. Use of +// this source code is governed by a BSD-style license that can be found in +// the LICENSE file. +// +// Package excelize providing a set of functions that allow you to write to +// and read from XLSX files. Support reads and writes XLSX file generated by +// Microsoft Excel™ 2007 and later. Support save file without losing original +// charts of XLSX. This library needs Go version 1.10 or later. + +package excelize + +import ( + "bytes" + "encoding/xml" + "errors" + "fmt" + "io/ioutil" + "os" + "reflect" +) + +// StreamWriter defined the type of stream writer. +type StreamWriter struct { + tmpFile *os.File + File *File + Sheet string + SheetID int + SheetData bytes.Buffer +} + +// NewStreamWriter return stream writer struct by given worksheet name for +// generate new worksheet with large amounts of data. Note that after set +// rows, you must call the 'Flush' method to end the streaming writing +// process and ensure that the order of line numbers is ascending. For +// example, set data for worksheet of size 102400 rows x 50 columns with +// numbers: +// +// file := excelize.NewFile() +// streamWriter, err := file.NewStreamWriter("Sheet1") +// if err != nil { +// panic(err) +// } +// for rowID := 1; rowID <= 102400; rowID++ { +// row := make([]interface{}, 50) +// for colID := 0; colID < 50; colID++ { +// row[colID] = rand.Intn(640000) +// } +// cell, _ := excelize.CoordinatesToCellName(1, rowID) +// if err := streamWriter.SetRow(cell, &row); err != nil { +// panic(err) +// } +// } +// if err := streamWriter.Flush(); err != nil { +// panic(err) +// } +// if err := file.SaveAs("Book1.xlsx"); err != nil { +// panic(err) +// } +// +func (f *File) NewStreamWriter(sheet string) (*StreamWriter, error) { + sheetID := f.GetSheetIndex(sheet) + if sheetID == 0 { + return nil, fmt.Errorf("sheet %s is not exist", sheet) + } + rsw := &StreamWriter{ + File: f, + Sheet: sheet, + SheetID: sheetID, + } + rsw.SheetData.WriteString("<sheetData>") + return rsw, nil +} + +// SetRow writes an array to streaming row by given worksheet name, starting +// coordinate and a pointer to array type 'slice'. Note that, cell settings +// with styles are not supported currently and after set rows, you must call the +// 'Flush' method to end the streaming writing process. The following +// shows the supported data types: +// +// int +// string +// +func (sw *StreamWriter) SetRow(axis string, slice interface{}) error { + col, row, err := CellNameToCoordinates(axis) + if err != nil { + return err + } + // Make sure 'slice' is a Ptr to Slice + v := reflect.ValueOf(slice) + if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Slice { + return errors.New("pointer to slice expected") + } + v = v.Elem() + sw.SheetData.WriteString(fmt.Sprintf(`<row r="%d">`, row)) + for i := 0; i < v.Len(); i++ { + axis, err := CoordinatesToCellName(col+i, row) + if err != nil { + return err + } + switch val := v.Index(i).Interface().(type) { + case int: + sw.SheetData.WriteString(fmt.Sprintf(`<c r="%s"><v>%d</v></c>`, axis, val)) + case string: + sw.SheetData.WriteString(sw.setCellStr(axis, val)) + default: + sw.SheetData.WriteString(sw.setCellStr(axis, fmt.Sprint(val))) + } + } + sw.SheetData.WriteString(`</row>`) + // Try to use local storage + chunk := 1 << 24 + if sw.SheetData.Len() >= chunk { + if sw.tmpFile == nil { + err := sw.createTmp() + if err != nil { + // can not use local storage + return nil + } + } + // use local storage + _, err := sw.tmpFile.Write(sw.SheetData.Bytes()) + if err != nil { + return nil + } + sw.SheetData.Reset() + } + return err +} + +// Flush ending the streaming writing process. +func (sw *StreamWriter) Flush() error { + sw.SheetData.WriteString(`</sheetData>`) + + ws, err := sw.File.workSheetReader(sw.Sheet) + if err != nil { + return err + } + sheetXML := fmt.Sprintf("xl/worksheets/sheet%d.xml", sw.SheetID) + delete(sw.File.Sheet, sheetXML) + delete(sw.File.checked, sheetXML) + var sheetDataByte []byte + if sw.tmpFile != nil { + // close the local storage file + if err = sw.tmpFile.Close(); err != nil { + return err + } + + file, err := os.Open(sw.tmpFile.Name()) + if err != nil { + return err + } + + sheetDataByte, err = ioutil.ReadAll(file) + if err != nil { + return err + } + + if err := file.Close(); err != nil { + return err + } + + err = os.Remove(sw.tmpFile.Name()) + if err != nil { + return err + } + } + + sheetDataByte = append(sheetDataByte, sw.SheetData.Bytes()...) + replaceMap := map[string][]byte{ + "XMLName": []byte{}, + "SheetData": sheetDataByte, + } + sw.SheetData.Reset() + sw.File.XLSX[fmt.Sprintf("xl/worksheets/sheet%d.xml", sw.SheetID)] = + StreamMarshalSheet(ws, replaceMap) + return err +} + +// createTmp creates a temporary file in the operating system default +// temporary directory. +func (sw *StreamWriter) createTmp() (err error) { + sw.tmpFile, err = ioutil.TempFile(os.TempDir(), "excelize-") + return err +} + +// StreamMarshalSheet provides method to serialization worksheets by field as +// streaming. +func StreamMarshalSheet(ws *xlsxWorksheet, replaceMap map[string][]byte) []byte { + s := reflect.ValueOf(ws).Elem() + typeOfT := s.Type() + var marshalResult []byte + marshalResult = append(marshalResult, []byte(XMLHeader+`<worksheet`+templateNamespaceIDMap)...) + for i := 0; i < s.NumField(); i++ { + f := s.Field(i) + content, ok := replaceMap[typeOfT.Field(i).Name] + if ok { + marshalResult = append(marshalResult, content...) + continue + } + out, _ := xml.Marshal(f.Interface()) + marshalResult = append(marshalResult, out...) + } + marshalResult = append(marshalResult, []byte(`</worksheet>`)...) + return marshalResult +} + +// setCellStr provides a function to set string type value of a cell as +// streaming. Total number of characters that a cell can contain 32767 +// characters. +func (sw *StreamWriter) setCellStr(axis, value string) string { + if len(value) > 32767 { + value = value[0:32767] + } + // Leading and ending space(s) character detection. + if len(value) > 0 && (value[0] == 32 || value[len(value)-1] == 32) { + return fmt.Sprintf(`<c xml:space="preserve" r="%s" t="str"><v>%s</v></c>`, axis, value) + } + return fmt.Sprintf(`<c r="%s" t="str"><v>%s</v></c>`, axis, value) +} |