mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
129 lines
3.6 KiB
Go
129 lines
3.6 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 "context"
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// pdfObjectChunkLimit 限制导入暂存片段的容量，不限制页面对象数量
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const pdfObjectChunkLimit = 256
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// pdfObjectBuffer 分块收集导入对象，提交前只整理一次连续数据
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type pdfObjectBuffer struct {
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parts [][]GraphicObject
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size int
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}
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// objectValidation 在单次导入中共享不可变资源的校验结果，隔离局部编辑器
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// 返回: *editorValidation 当前编辑器的构建校验会话
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func (p *pdfImporter) objectValidation() *editorValidation {
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if p.validation == nil || p.validation.Editor != p.editor {
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p.validation = &editorValidation{Editor: p.editor}
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}
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return p.validation
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}
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// appendObject 追加本次导入对象，按需建立独立暂存缓冲
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// 入参: object 独立导入对象
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func (p *pdfImporter) appendObject(object GraphicObject) {
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if p.objects == nil {
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p.objects = &pdfObjectBuffer{}
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}
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p.objects.append(object)
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}
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// append 追加对象，小批量连续存储，超过阈值后不复制前序片段
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// 入参: object 独立对象
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func (b *pdfObjectBuffer) append(object GraphicObject) {
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index := len(b.parts) - 1
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if index == 0 && len(b.parts[0]) == cap(b.parts[0]) && cap(b.parts[0]) < pdfObjectChunkLimit {
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part := b.parts[0]
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next := make([]GraphicObject, len(part), min(pdfObjectChunkLimit, max(1, cap(part)*2)))
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copy(next, part)
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b.parts[0] = next
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}
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if index < 0 || len(b.parts[index]) == cap(b.parts[index]) {
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capacity := pdfObjectChunkLimit
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if index < 0 {
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capacity = 1
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}
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b.parts = append(b.parts, make([]GraphicObject, 0, capacity))
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index++
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}
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b.parts[index] = append(b.parts[index], object)
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b.size++
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}
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// len 获取暂存对象数量，空缓冲返回零
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// 返回: int 对象数量
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func (b *pdfObjectBuffer) len() int {
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if b == nil {
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return 0
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}
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return b.size
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}
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// truncate 回滚到已有对象位置，清理丢弃对象及片段引用
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// 入参: size 保留对象数量
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func (b *pdfObjectBuffer) truncate(size int) {
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if size < 0 || size > b.len() {
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panic("invalid PDF object buffer size")
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}
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if size == b.len() {
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return
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}
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remaining := size
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for index, part := range b.parts {
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if remaining <= len(part) {
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clear(part[remaining:])
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b.parts[index] = part[:remaining]
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clear(b.parts[index+1:])
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b.parts = b.parts[:index+1]
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b.size = size
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return
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}
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remaining -= len(part)
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}
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}
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// data 按绘制顺序整理独立对象数组，取消时保留原片段供重试
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// 入参: ctx 取消上下文
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// 返回: []GraphicObject 暂存数据, error 取消错误
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func (b *pdfObjectBuffer) data(ctx context.Context) ([]GraphicObject, error) {
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if err := ctx.Err(); err != nil {
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return nil, err
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}
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if b.len() == 0 {
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return nil, nil
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}
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if len(b.parts) == 1 {
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return b.parts[0][:b.size:b.size], nil
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}
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objects := make([]GraphicObject, b.size)
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offset := 0
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for _, part := range b.parts {
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if err := ctx.Err(); err != nil {
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return nil, err
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}
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offset += copy(objects[offset:], part)
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}
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if err := ctx.Err(); err != nil {
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return nil, err
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}
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b.parts[0] = objects
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clear(b.parts[1:])
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b.parts = b.parts[:1]
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return objects, nil
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}
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