mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 08:46:55 +08:00
266 lines
9.4 KiB
Go
266 lines
9.4 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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"context"
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"crypto/sha256"
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"errors"
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"fmt"
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"github.com/xiaoqidun/pdfgo"
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)
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// pdfAttachmentKey 按显示名与原始数据复用PDF附件，不合并名称不同的附件
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type pdfAttachmentKey struct {
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name string
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digest [32]byte
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}
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// pdfEmbeddedFile 保存目标路径的容器与原始文件，阅读器按需打开
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type pdfEmbeddedFile struct {
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reader *pdfgo.Reader
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file *pdfgo.FileSpecification
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data []byte
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}
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// documentAttachments 导入文档名称树中的附件，与注解及动作引用共用附件资源
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// 入参: ctx 取消上下文
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// 返回: error 名称树、附件读取或写入错误
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func (p *pdfImporter) documentAttachments(ctx context.Context) error {
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return p.reader.WalkEmbeddedFiles(ctx, func(_ string, file pdfgo.FileSpecification) error {
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if file.Embedded == nil {
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if p.warning == nil {
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return fmt.Errorf("PDF embedded file has no embedded data")
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}
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p.warning(pdfgo.Diagnostic{Message: "PDF embedded file without embedded data ignored"})
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return nil
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}
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data, err := file.Embedded.DecodeContext(ctx)
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if err != nil {
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var unsupported *pdfgo.UnsupportedError
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if p.warning != nil && errors.As(err, &unsupported) {
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p.warning(pdfgo.Diagnostic{Message: "PDF document attachment not transferred to OFD: " + err.Error()})
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return nil
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}
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return err
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}
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_, err = p.attachmentFile(file.Name, data)
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return err
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})
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}
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// launchLinkAction 保留文件打开目标，不执行应用程序或猜测平台启动参数
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// 入参: object 启动动作, strict 是否禁止启动语义损失
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// 返回: *Action 附件动作, error 解析、取消或无法表达的语义
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func (p *pdfImporter) launchLinkAction(object pdfgo.Object, strict bool) (*Action, error) {
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action, err := p.reader.ReadLaunchAction(p.ctx, object)
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if err != nil {
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return nil, err
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}
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if action.File == nil || action.Windows != nil || action.Mac != nil || action.Unix != nil {
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if strict {
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return nil, &pdfgo.UnsupportedError{Feature: "platform launch action conversion"}
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}
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p.warning(pdfgo.Diagnostic{Message: "PDF platform launch parameters not transferred to OFD; appearance retained"})
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return nil, nil
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}
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if strict && action.NewWindow == nil {
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return nil, &pdfgo.UnsupportedError{Feature: "launch reader window preference conversion"}
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}
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data, available, err := p.mediaData(p.ctx, *action.File)
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if err != nil || !available {
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return nil, err
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}
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pdfTarget := bytes.HasPrefix(bytes.TrimSpace(data[:min(len(data), 1024)]), []byte("%PDF-"))
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if !pdfTarget && strict {
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return nil, &pdfgo.UnsupportedError{Feature: "application or non-PDF launch action conversion"}
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}
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id, err := p.attachmentFile(action.File.Name, data)
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if err != nil {
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return nil, err
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}
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window := action.NewWindow
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if !pdfTarget {
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window = nil
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p.warning(pdfgo.Diagnostic{Message: "PDF launch target retained as attachment; application execution not transferred to OFD"})
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} else if window == nil {
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p.warning(pdfgo.Diagnostic{Message: "PDF launch target retained as attachment; reader window preference not transferred to OFD"})
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}
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return &Action{Event: "CLICK", GotoA: &GotoA{AttachID: id, NewWindow: window}}, nil
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}
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// remoteLinkAction 保留调用方提供的远程文件，不生成OFD无法表达的文件内目标
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// 入参: object 远程跳转动作, strict 是否禁止目标语义损失
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// 返回: *Action 附件动作, error 结构、取消或转换错误
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func (p *pdfImporter) remoteLinkAction(object pdfgo.Object, strict bool) (*Action, error) {
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action, err := p.reader.ReadExternalGoToAction(p.ctx, object)
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if err != nil {
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return nil, err
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}
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if strict {
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return nil, &pdfgo.UnsupportedError{Feature: "remote document destination conversion"}
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}
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if p.resolveFile == nil {
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: "PDF remote link file unavailable: " + action.File.Name + "; appearance retained, remote destination not transferred to OFD"})
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return nil, nil
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}
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data, err := p.reader.ReadFileData(p.ctx, *action.File, p.resolveFile)
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if err != nil {
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return nil, err
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}
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id, err := p.attachmentFile(action.File.Name, data)
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if err != nil {
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return nil, err
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}
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message := "PDF remote link target retained as attachment; destination inside attached PDF not transferred to OFD"
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if action.NewWindow == nil {
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message += "; reader window preference not transferred"
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}
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: message})
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return &Action{Event: "CLICK", GotoA: &GotoA{AttachID: id, NewWindow: action.NewWindow}}, nil
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}
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// embeddedLinkAction 按目标路径定位附件，回到源文档时保留页内目标
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// 入参: object 嵌入文件动作, strict 是否禁止附件内目标语义损失
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// 返回: *Action 附件动作, pdfgo.Object 源文档目标, error 目标或转换错误
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func (p *pdfImporter) embeddedLinkAction(object pdfgo.Object, strict bool) (*Action, pdfgo.Object, error) {
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action, err := p.reader.ReadExternalGoToAction(p.ctx, object)
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if err != nil {
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return nil, nil, err
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}
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stack := []pdfEmbeddedFile{{reader: p.reader}}
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if action.File != nil {
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data, available, err := p.mediaData(p.ctx, *action.File)
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if err != nil || !available {
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return nil, nil, err
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}
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stack[0] = pdfEmbeddedFile{file: action.File, data: data}
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}
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var opened []*pdfgo.Reader
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defer func() {
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for _, reader := range opened {
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reader.Close()
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}
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}()
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open := func(file *pdfEmbeddedFile) error {
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if file.reader != nil {
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return nil
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}
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if err := p.ctx.Err(); err != nil {
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return err
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}
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if file.data == nil {
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var err error
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file.data, err = p.reader.ReadFileData(p.ctx, *file.file, p.resolveFile)
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if err != nil {
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return err
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}
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}
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reader, err := pdfgo.NewReaderWithOptions(bytes.NewReader(file.data), int64(len(file.data)), pdfgo.ReaderOptions{Warning: p.warning})
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if err != nil {
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return err
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}
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file.reader = reader
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opened = append(opened, reader)
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return p.ctx.Err()
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}
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for _, target := range action.Target {
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if err := p.ctx.Err(); err != nil {
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return nil, nil, err
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}
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if target.Relation == "P" {
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if len(stack) == 1 {
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if strict {
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return nil, nil, &pdfgo.UnsupportedError{Feature: "embedded link parent document unavailable"}
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}
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: "PDF embedded link parent document unavailable; link omitted"})
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return nil, nil, nil
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}
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stack = stack[:len(stack)-1]
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continue
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}
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current := &stack[len(stack)-1]
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if err := open(current); err != nil {
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return nil, nil, err
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}
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file, err := current.reader.ReadEmbeddedTargetFile(p.ctx, target)
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if err != nil {
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if !strict && errors.Is(err, pdfgo.ErrDestinationNotFound) {
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: fmt.Sprintf("%v; link omitted", err)})
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return nil, nil, nil
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}
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return nil, nil, err
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}
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stack = append(stack, pdfEmbeddedFile{file: &file})
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}
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current := &stack[len(stack)-1]
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if current.file == nil {
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destination, err := current.reader.ResolveRemoteDestination(p.ctx, action.Destination)
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if err != nil {
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if !strict && errors.Is(err, pdfgo.ErrDestinationNotFound) {
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: fmt.Sprintf("%v; link omitted", err)})
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return nil, nil, nil
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}
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return nil, nil, err
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}
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if action.NewWindow != nil && *action.NewWindow {
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if strict {
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return nil, nil, &pdfgo.UnsupportedError{Feature: "embedded link to source document in new window"}
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}
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: "PDF embedded link new window not transferred to OFD; source document destination retained"})
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}
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return nil, append(pdfgo.Array{destination.Page, destination.Mode}, destination.Parameters...), nil
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}
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if strict {
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return nil, nil, &pdfgo.UnsupportedError{Feature: "destination inside attached PDF"}
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}
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if current.data == nil {
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current.data, err = p.reader.ReadFileData(p.ctx, *current.file, p.resolveFile)
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if err != nil {
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return nil, nil, err
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}
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}
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id, err := p.attachmentFile(current.file.Name, current.data)
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if err != nil {
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return nil, nil, err
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}
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p.warning(pdfgo.Diagnostic{Page: p.page + 1, Message: "PDF embedded link target retained as attachment; destination inside attached PDF not transferred to OFD"})
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return &Action{Event: "CLICK", GotoA: &GotoA{AttachID: id, NewWindow: action.NewWindow}}, nil, nil
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}
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// attachmentFile 添加或复用PDF附件，缺少显示名时使用固定名称，不改原始文件内容
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// 入参: name 附件显示名, data 原始文件数据
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// 返回: string 附件标识, error 附件写入错误
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func (p *pdfImporter) attachmentFile(name string, data []byte) (string, error) {
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if name == "" {
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name = "Attachment"
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}
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key := pdfAttachmentKey{name: name, digest: sha256.Sum256(data)}
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if id, ok := p.attachmentIDs[key]; ok {
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return id, nil
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}
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id, err := p.editor.AddAttachment(name, data)
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if err != nil {
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return "", err
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}
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if p.attachmentIDs == nil {
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p.attachmentIDs = make(map[pdfAttachmentKey]string)
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}
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p.attachmentIDs[key] = id
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return id, nil
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}
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