mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 13:56:32 +08:00
266 lines
7.8 KiB
Go
266 lines
7.8 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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"encoding/binary"
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"fmt"
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"io"
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"maps"
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"slices"
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)
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// compactPackageFonts 清理无引用字体，补齐多文档及历史版本的字体裁剪，不修改编辑器快照
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// 入参: ctx 取消上下文, parts 输出修改, removed 待删除条目, generated 本次编码的页面引用
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// 返回: error 读取、结构或取消错误
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func (e *Editor) compactPackageFonts(ctx context.Context, parts map[string][]byte, removed map[string]bool, generated map[string]editorGeneratedReferences) error {
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reader := e.source.reader
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versioned := false
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for _, body := range reader.OFD.DocBody {
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versioned = versioned || body.versioned
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}
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if !versioned {
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if reader.DocumentCount() <= 1 || e.backends.FontResources == nil || e.output != nil && e.output.options.Mode != CompressionUnchanged {
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return nil
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}
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}
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protected, err := reader.hasOutputSignatures(ctx)
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if err != nil || protected {
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return err
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}
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view := &Reader{Zip: reader.Zip, files: maps.Clone(reader.files)}
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if view.files == nil {
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view.files = make(map[string][]byte)
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}
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maps.Copy(view.files, parts)
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if err := view.initRootContext(ctx); err != nil {
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return err
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}
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data, err := view.readFileViewContext(ctx, "OFD.xml")
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if err != nil {
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return err
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}
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root, err := parseEditorXMLContext(ctx, data)
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if err != nil {
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return err
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}
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candidates, seen := make(map[string]bool), make(map[string]bool)
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for _, body := range root.children {
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if err := ctx.Err(); err != nil {
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return err
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}
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if !body.matchesOFD("DocBody") {
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continue
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}
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versions, err := parseVersionEntries(ctx, body)
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if err != nil {
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return err
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}
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for _, entry := range versions {
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version, err := view.readDocumentVersionContext(ctx, entry.ID, entry.Location)
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if err != nil {
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return fmt.Errorf("version %s: %w", entry.ID, err)
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}
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for _, file := range version.Files {
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if err := ctx.Err(); err != nil {
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return err
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}
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name := file.Location
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if seen[name] || removed[name] {
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continue
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}
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seen[name] = true
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candidate, err := view.fontCleanupCandidate(ctx, name)
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if err != nil {
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return err
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}
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if candidate {
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candidates[name] = true
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}
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}
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}
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}
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if err := pruneUnreferencedFiles(ctx, view, slices.Collect(maps.Keys(candidates))...); err != nil {
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return err
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}
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if err := e.subsetPackageFonts(ctx, view, removed, generated); err != nil {
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return err
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}
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for name, data := range view.files {
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if original, ok := reader.files[name]; !ok || !bytes.Equal(original, data) {
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parts[name] = data
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}
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}
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for name := range candidates {
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if !view.fileNames[name] {
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removed[name] = true
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delete(parts, name)
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}
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}
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return nil
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}
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// fontCleanupCandidate 检查字体目录与文件范围，仅将可识别字体交给引用清理流程
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// 入参: ctx 取消上下文, name 包内文件路径
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// 返回: bool 是否为候选字体, error 读取或取消错误
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func (r *Reader) fontCleanupCandidate(ctx context.Context, name string) (bool, error) {
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input, err := r.openFile(name)
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if err != nil {
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return false, err
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}
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defer input.Close()
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var size uint64
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if data, ok := r.files[cleanPackagePath(name)]; ok {
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size = uint64(len(data))
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} else if file, ok := r.packageFile(name); ok {
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size = file.UncompressedSize64
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}
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candidate, err := fontCleanupDirectory(imageInput{ReadCloser: input, ctx: ctx}, size)
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if err == io.EOF || err == io.ErrUnexpectedEOF {
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err = nil
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}
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if canceled := ctx.Err(); canceled != nil {
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return false, canceled
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}
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return candidate, err
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}
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// fontCleanupDirectory 检查SFNT表目录或字体集合索引，不读取字形数据
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// 入参: input 文件流, size 文件长度
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// 返回: bool 是否具有有效目录, error 读取错误
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func fontCleanupDirectory(input io.Reader, size uint64) (bool, error) {
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var header [12]byte
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if _, err := io.ReadFull(input, header[:]); err != nil {
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return false, err
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}
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if size < uint64(len(header)) {
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return false, nil
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}
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if string(header[:4]) == "ttcf" {
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version := binary.BigEndian.Uint32(header[4:])
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count := uint64(binary.BigEndian.Uint32(header[8:]))
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if version != 0x00010000 && version != 0x00020000 || count == 0 || count > (size-12)/4 {
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return false, nil
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}
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end := 12 + count*4
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if version == 0x00020000 {
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end += 12
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}
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var entry [4]byte
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for range count {
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if _, err := io.ReadFull(input, entry[:]); err != nil {
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return false, err
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}
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offset := uint64(binary.BigEndian.Uint32(entry[:]))
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if offset < end || offset > size-12 {
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return false, nil
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}
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}
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return true, nil
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}
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switch string(header[:4]) {
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case "\x00\x01\x00\x00", "OTTO", "true":
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default:
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return false, nil
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}
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count := uint64(binary.BigEndian.Uint16(header[4:]))
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if count == 0 || count > (size-12)/16 {
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return false, nil
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}
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end := 12 + count*16
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seen := make(map[uint32]bool, count)
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var entry [16]byte
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for range count {
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if _, err := io.ReadFull(input, entry[:]); err != nil {
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return false, err
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}
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tag := binary.BigEndian.Uint32(entry[:])
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offset := uint64(binary.BigEndian.Uint32(entry[8:]))
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length := uint64(binary.BigEndian.Uint32(entry[12:]))
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if seen[tag] || offset < end || offset > size || length > size-offset {
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return false, nil
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}
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seen[tag] = true
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}
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return true, nil
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}
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// subsetPackageFonts 按文档作用域收集用字，合并共享字体需求并保留字形编号
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// 入参: ctx 取消上下文, view 独立输出快照, removed 待删除条目, generated 本次编码的页面引用
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// 返回: error 读取、裁剪或取消错误
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func (e *Editor) subsetPackageFonts(ctx context.Context, view *Reader, removed map[string]bool, generated map[string]editorGeneratedReferences) error {
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if e.backends.FontResources == nil {
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return nil
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}
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names := maps.Clone(view.fileNames)
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for name := range removed {
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delete(names, name)
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}
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progress := editorProgress(e.OnWriteProgress)
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refs, resources, references, safe, err := scanEditorResources(ctx, view, view.files, generated, names, progress, true)
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if err != nil || !safe {
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return err
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}
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scoped, err := resourceReferenceScopes(ctx, refs.documents, resources, references, "")
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if err != nil || scoped == nil {
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return err
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}
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read := func(name string) ([]byte, error) { return view.readFileViewContext(ctx, name) }
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usage, err := resourceFontUsage(ctx, resources, scoped, read)
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if err != nil {
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return err
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}
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for _, source := range references {
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for name := range source.files {
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if font := usage[name]; font != nil && !source.versions[name] {
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font.unsafe = true
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}
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}
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for _, definition := range source.definitions {
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for name := range definition.files {
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if font := usage[name]; font != nil {
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font.unsafe = true
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}
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}
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}
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}
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var cache editorSourceFontCache
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for index, name := range slices.Sorted(maps.Keys(usage)) {
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if err := progress.report("fonts", index, len(usage)); err != nil {
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return err
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}
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if usage[name].unsafe || len(usage[name].chars)+len(usage[name].glyphs) == 0 {
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continue
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}
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data, err := read(name)
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if err != nil {
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return err
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}
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subset, err := cache.subset(ctx, e.backends.FontResources, data, usage[name])
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if err != nil {
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return err
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}
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if subset != nil {
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view.files[name] = subset
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}
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}
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if err := progress.report("fonts", len(usage), len(usage)); err != nil {
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return err
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}
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return ctx.Err()
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}
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