mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
463 lines
15 KiB
Go
463 lines
15 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ofdgo
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import (
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"bytes"
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"encoding/xml"
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"fmt"
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"io"
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"slices"
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"strings"
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)
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// editorXML 保存XML节点的原文位置，不重写未修改的内容。
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type editorXML struct {
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name xml.Name
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attrs []xml.Attr
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start, open, close, end int
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children []*editorXML
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parent *editorXML
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}
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// editorXMLPatch 替换原文中的连续区间。
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type editorXMLPatch struct {
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start, end int
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data []byte
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}
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// parseEditorXML 解析节点位置，保留命名空间、注释和原始格式。
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// 入参: data XML原文
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// 返回: *editorXML 根节点, error 错误信息
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func parseEditorXML(data []byte) (*editorXML, error) {
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d := xml.NewDecoder(bytes.NewReader(data))
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var root *editorXML
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var stack []*editorXML
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for {
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start := int(d.InputOffset())
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token, err := d.Token()
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if err == io.EOF {
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break
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}
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if err != nil {
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return nil, err
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}
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switch token := token.(type) {
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case xml.StartElement:
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node := &editorXML{name: token.Name, attrs: token.Attr, start: start, open: int(d.InputOffset())}
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if len(stack) == 0 {
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if root != nil {
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return nil, fmt.Errorf("multiple XML roots")
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}
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root = node
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} else {
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parent := stack[len(stack)-1]
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node.parent = parent
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parent.children = append(parent.children, node)
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}
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stack = append(stack, node)
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case xml.EndElement:
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node := stack[len(stack)-1]
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node.close, node.end = start, int(d.InputOffset())
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stack = stack[:len(stack)-1]
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}
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}
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if root == nil {
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return nil, fmt.Errorf("empty XML document")
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}
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return root, nil
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}
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// child 查找OFD直接子节点。
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// 入参: name 节点名称
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// 返回: *editorXML 节点，不存在时为nil
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func (n *editorXML) child(name string) *editorXML {
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for _, child := range n.children {
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if child.name.Local == name && (child.name.Space == n.name.Space || child.name.Space == ofdNamespace || child.name.Space == "") {
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return child
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}
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}
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return nil
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}
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// attr 获取无命名空间的属性值。
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// 入参: name 属性名称
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// 返回: string 属性值
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func (n *editorXML) attr(name string) string {
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for _, attr := range n.attrs {
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if attr.Name.Space == "" && attr.Name.Local == name {
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return attr.Value
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}
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}
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return ""
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}
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// editorPatchXML 按位置应用互不重叠的替换。
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// 入参: data 原文, patches 修改区间
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// 返回: []byte 修改后的XML
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func editorPatchXML(data []byte, patches []editorXMLPatch) []byte {
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slices.SortStableFunc(patches, func(a, b editorXMLPatch) int {
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if a.start != b.start {
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return a.start - b.start
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}
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return a.end - b.end
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})
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var result bytes.Buffer
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position := 0
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for _, patch := range patches {
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result.Write(data[position:patch.start])
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result.Write(patch.data)
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position = patch.end
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}
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result.Write(data[position:])
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return result.Bytes()
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}
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// editorXMLContent 替换节点内部内容，兼容自闭合节点。
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// 入参: data 原文, node 节点, content 新内容
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// 返回: editorXMLPatch 修改区间
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func editorXMLContent(data []byte, node *editorXML, content []byte) editorXMLPatch {
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if node.open != node.end {
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return editorXMLPatch{node.open, node.close, content}
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}
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header := data[node.start:node.open]
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end := bytes.IndexAny(header[1:], " \t\r\n/>") + 1
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name := header[1:end]
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replacement := append(bytes.Clone(header[:len(header)-2]), '>')
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replacement = append(replacement, content...)
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replacement = append(replacement, []byte("</"+string(name)+">")...)
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return editorXMLPatch{node.start, node.end, replacement}
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}
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// editorXMLText 编码带独立命名空间的文本节点。
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// 入参: name 节点名称, value 文本
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// 返回: []byte XML片段
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func editorXMLText(name, value string) []byte {
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var escaped bytes.Buffer
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_ = xml.EscapeText(&escaped, []byte(value))
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return []byte("<ofd:" + name + " xmlns:ofd=\"" + ofdNamespace + "\">" + escaped.String() + "</ofd:" + name + ">")
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}
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// editorXMLSetText 更新或追加直接子节点，保留其他节点。
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// 入参: data 原文, node 父节点, values 需要修改的字段
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// 返回: []byte 修改后的XML
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func editorXMLSetText(data []byte, node *editorXML, values [][2]string) []byte {
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var patches []editorXMLPatch
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var added []byte
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order := []string{"PhysicalBox", "ApplicationBox", "ContentBox", "BleedBox"}
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if node.name.Local == "DocInfo" {
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order = []string{"DocID", "Title", "Author", "Subject", "Abstract", "CreationDate", "ModDate", "DocUsage", "Cover", "Keywords", "Creator", "CreatorVersion", "CustomDatas"}
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}
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for _, value := range values {
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child := node.child(value[0])
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var encoded []byte
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if value[1] != "" {
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encoded = editorXMLText(value[0], value[1])
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}
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if child != nil {
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patches = append(patches, editorXMLPatch{child.start, child.end, encoded})
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} else if node.open == node.end {
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added = append(added, encoded...)
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} else if len(encoded) != 0 {
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position := node.close
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for _, next := range node.children {
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if slices.Index(order, next.name.Local) > slices.Index(order, value[0]) {
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position = next.start
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break
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}
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}
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patches = append(patches, editorXMLPatch{position, position, encoded})
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}
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}
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if len(added) != 0 {
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patches = append(patches, editorXMLContent(data, node, added))
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}
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return editorPatchXML(data, patches)
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}
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// editorXMLObjects 递归登记图层和页块内的对象位置，保留原容器层级。
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// 入参: container 图层或页块, nodes 标识与节点映射
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// 返回: error 错误信息
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func editorXMLObjects(container *editorXML, nodes map[string]*editorXML) error {
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for _, node := range container.children {
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if id := node.attr("ID"); id != "" {
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if nodes[id] != nil {
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return fmt.Errorf("duplicate object ID %q", id)
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}
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nodes[id] = node
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}
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if node.name.Local == "PageBlock" {
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if err := editorXMLObjects(node, nodes); err != nil {
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return err
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}
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}
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}
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return nil
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}
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// editorXMLAttributes 判断节点的命名空间与属性是否在编辑器支持范围内。
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// 入参: node 节点, allowed 允许的属性名称
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// 返回: bool 是否支持
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func editorXMLAttributes(node *editorXML, allowed string) bool {
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if node.name.Space != "" && node.name.Space != ofdNamespace && node.name.Space != "http://www.ofdspec.org" {
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return false
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}
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for _, attr := range node.attrs {
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if attr.Name.Space == "xmlns" || attr.Name.Local == "xmlns" && attr.Name.Space == "" {
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continue
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}
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if attr.Name.Space != "" || !slices.Contains(strings.Fields(allowed), attr.Name.Local) {
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return false
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}
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}
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return true
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}
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// editorXMLSupported 判断原文是否仅包含创建器能够保留的对象字段。
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// 入参: node 对象或子节点
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// 返回: bool 是否支持完整编辑
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func editorXMLSupported(node *editorXML) bool {
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var allowed, children string
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switch node.name.Local {
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case "TextObject":
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allowed, children = "ID Boundary CTM DrawParam Font Size HScale Weight ReadDirection CharDirection LineWidth MiterLimit Join Italic Visible Stroke Fill Alpha", "Clips FillColor StrokeColor TextCode"
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case "PathObject", "Path":
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allowed, children = "Boundary CTM LineWidth MiterLimit Join Cap Rule DashPattern DashOffset Visible Stroke Fill Alpha", "StrokeColor FillColor AbbreviatedData"
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if node.name.Local == "PathObject" {
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allowed += " ID DrawParam"
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children += " Clips"
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}
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case "ImageObject":
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allowed, children = "ID Boundary CTM ResourceID ImageMask Visible Alpha", "Clips"
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case "TextCode":
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allowed = "X Y DeltaX DeltaY"
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case "FillColor", "StrokeColor":
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allowed = "Value Alpha"
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case "Clips":
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allowed, children = "TransFlag", "Clip"
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case "Clip":
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children = "Area"
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case "Area":
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allowed, children = "CTM", "Path"
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case "AbbreviatedData":
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default:
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return false
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}
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if !editorXMLAttributes(node, allowed) {
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return false
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}
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for _, child := range node.children {
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if !slices.Contains(strings.Fields(children), child.name.Local) || !editorXMLSupported(child) {
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return false
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}
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}
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return true
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}
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// editorXMLObject 修改对象发生变化的属性与内容，保留原文中的显式默认值。
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// 有效样式快照在修改后展开原绘制参数，避免已清除的属性重新继承。
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// 入参: data 页面原文, node 原对象节点, before 原对象, after 新对象
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// 返回: []byte 对象XML, error 错误信息
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func editorXMLObject(data []byte, node *editorXML, before, after GraphicObject) ([]byte, error) {
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if before.Type != after.Type {
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return editorObjectXML(after)
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}
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if node.attr("DrawParam") != "" && before.TextObject.DrawParam == "" && before.PathObject.DrawParam == "" {
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before = GraphicObject{Type: before.Type}
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var err error
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switch before.Type {
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case "TextObject":
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err = xml.Unmarshal(data[node.start:node.end], &before.TextObject)
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case "PathObject":
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err = xml.Unmarshal(data[node.start:node.end], &before.PathObject)
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}
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if err != nil {
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return nil, err
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}
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}
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oldXML, err := editorObjectXML(before)
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if err != nil {
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return nil, err
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}
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newXML, err := editorObjectXML(after)
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if err != nil {
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return nil, err
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}
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return editorXMLMerge(data, node, oldXML, newXML)
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}
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// editorXMLMerge 按标准编码的差异更新原节点，递归保留未变化的显式默认值与命名空间。
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// 入参: data 原文, node 原节点, oldXML 修改前编码, newXML 修改后编码
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// 返回: []byte 更新节点, error 错误信息
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func editorXMLMerge(data []byte, node *editorXML, oldXML, newXML []byte) ([]byte, error) {
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oldNode, err := parseEditorXML(oldXML)
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if err != nil {
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return nil, err
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}
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newNode, err := parseEditorXML(newXML)
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if err != nil {
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return nil, err
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}
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changes := make(map[string]string)
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for _, attr := range append(oldNode.attrs, newNode.attrs...) {
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if attr.Name.Space == "" && oldNode.attr(attr.Name.Local) != newNode.attr(attr.Name.Local) {
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changes[attr.Name.Local] = newNode.attr(attr.Name.Local)
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}
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}
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contentChanged := !bytes.Equal(oldXML[oldNode.open:oldNode.close], newXML[newNode.open:newNode.close])
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if len(changes) == 0 && !contentChanged {
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return bytes.Clone(data[node.start:node.end]), nil
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}
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d := xml.NewDecoder(bytes.NewReader(data[node.start:node.open]))
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token, err := d.RawToken()
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if err != nil {
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return nil, err
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}
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start := token.(xml.StartElement)
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var result bytes.Buffer
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name := start.Name.Local
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if start.Name.Space != "" {
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name = start.Name.Space + ":" + name
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}
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result.WriteString("<" + name)
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for _, attr := range start.Attr {
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if attr.Name.Space == "" {
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if value, ok := changes[attr.Name.Local]; ok {
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attr.Value = value
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delete(changes, attr.Name.Local)
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if value == "" {
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continue
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}
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}
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}
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if contentChanged && attr.Name.Space == "xmlns" && attr.Name.Local == "ofd" {
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continue
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}
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key := attr.Name.Local
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if attr.Name.Space != "" {
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key = attr.Name.Space + ":" + key
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}
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result.WriteString(" " + key + "=\"")
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_ = xml.EscapeText(&result, []byte(attr.Value))
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result.WriteByte('"')
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}
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for _, attr := range newNode.attrs {
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if value, ok := changes[attr.Name.Local]; ok && value != "" {
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result.WriteString(" " + attr.Name.Local + "=\"")
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_ = xml.EscapeText(&result, []byte(value))
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result.WriteByte('"')
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}
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}
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if contentChanged {
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result.WriteString(" xmlns:ofd=\"" + ofdNamespace + "\"")
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}
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result.WriteByte('>')
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if contentChanged {
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matching := len(node.children) > 0 && len(node.children) == len(oldNode.children) && len(node.children) == len(newNode.children)
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if matching {
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for i, child := range node.children {
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if child.name.Local != oldNode.children[i].name.Local || child.name.Local != newNode.children[i].name.Local {
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matching = false
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break
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}
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}
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}
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if matching {
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position := node.open
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for i, child := range node.children {
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before, after := oldNode.children[i], newNode.children[i]
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updated, err := editorXMLMerge(data, child, oldXML[before.start:before.end], newXML[after.start:after.end])
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if err != nil {
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return nil, err
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}
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result.Write(data[position:child.start])
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result.Write(updated)
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position = child.end
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}
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result.Write(data[position:node.close])
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} else {
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result.Write(newXML[newNode.open:newNode.close])
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}
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} else if node.open != node.end {
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result.Write(data[node.open:node.close])
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}
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result.WriteString("</" + name + ">")
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return result.Bytes(), nil
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}
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// editorXMLContainer 用标准编码器封装已编码的子节点。
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// 入参: name 节点名称, attrs 属性, content 子节点XML
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// 返回: []byte XML片段, error 错误信息
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func editorXMLContainer(name string, attrs ofdAttrs, content []byte) ([]byte, error) {
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var output bytes.Buffer
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attrs.add("xmlns:ofd", ofdNamespace)
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value := struct {
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Content []byte `xml:",innerxml"`
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}{content}
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err := xml.NewEncoder(&output).EncodeElement(value, xml.StartElement{Name: xml.Name{Local: "ofd:" + name}, Attr: attrs})
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return output.Bytes(), err
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}
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// editorXMLStandalone 补齐原对象继承的命名空间，使跨页复制不依赖原父节点。
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// 入参: data 对象XML, source 原节点
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// 返回: []byte 独立XML片段, error 错误信息
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func editorXMLStandalone(data []byte, source *editorXML) ([]byte, error) {
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root, err := parseEditorXML(data)
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if err != nil {
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return nil, err
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}
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namespaces := make(map[string]string)
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for node := source.parent; node != nil; node = node.parent {
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for _, attr := range node.attrs {
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key := ""
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if attr.Name.Space == "xmlns" {
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key = "xmlns:" + attr.Name.Local
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}
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if attr.Name.Space == "" && attr.Name.Local == "xmlns" {
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key = "xmlns"
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}
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if key != "" {
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if _, exists := namespaces[key]; !exists {
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namespaces[key] = attr.Value
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}
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}
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}
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}
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for _, attr := range root.attrs {
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if attr.Name.Space == "xmlns" {
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delete(namespaces, "xmlns:"+attr.Name.Local)
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}
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if attr.Name.Space == "" && attr.Name.Local == "xmlns" {
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delete(namespaces, "xmlns")
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}
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}
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var added bytes.Buffer
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keys := make([]string, 0, len(namespaces))
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for key := range namespaces {
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keys = append(keys, key)
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}
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slices.Sort(keys)
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for _, key := range keys {
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added.WriteString(" " + key + "=\"")
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_ = xml.EscapeText(&added, []byte(namespaces[key]))
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added.WriteByte('"')
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}
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position := root.open - 1
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if data[position-1] == '/' {
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position--
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}
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return editorPatchXML(data, []editorXMLPatch{{position, position, added.Bytes()}}), nil
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}
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