485 lines
12 KiB
Go
485 lines
12 KiB
Go
package vfsgen
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import (
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"bytes"
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"compress/gzip"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"os"
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pathpkg "path"
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"sort"
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"strconv"
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"text/template"
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"time"
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"github.com/shurcooL/httpfs/vfsutil"
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)
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// Generate Go code that statically implements input filesystem,
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// write the output to a file specified in opt.
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func Generate(input http.FileSystem, opt Options) error {
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opt.fillMissing()
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// Use an in-memory buffer to generate the entire output.
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buf := new(bytes.Buffer)
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err := t.ExecuteTemplate(buf, "Header", opt)
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if err != nil {
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return err
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}
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var toc toc
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err = findAndWriteFiles(buf, input, &toc)
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if err != nil {
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return err
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}
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err = t.ExecuteTemplate(buf, "DirEntries", toc.dirs)
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if err != nil {
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return err
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}
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err = t.ExecuteTemplate(buf, "Trailer", toc)
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if err != nil {
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return err
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}
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// Write output file (all at once).
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fmt.Println("writing", opt.Filename)
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err = ioutil.WriteFile(opt.Filename, buf.Bytes(), 0644)
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return err
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}
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type toc struct {
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dirs []*dirInfo
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HasCompressedFile bool // There's at least one compressedFile.
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HasFile bool // There's at least one uncompressed file.
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}
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// fileInfo is a definition of a file.
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type fileInfo struct {
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Path string
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Name string
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ModTime time.Time
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UncompressedSize int64
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}
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// dirInfo is a definition of a directory.
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type dirInfo struct {
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Path string
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Name string
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ModTime time.Time
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Entries []string
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}
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// findAndWriteFiles recursively finds all the file paths in the given directory tree.
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// They are added to the given map as keys. Values will be safe function names
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// for each file, which will be used when generating the output code.
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func findAndWriteFiles(buf *bytes.Buffer, fs http.FileSystem, toc *toc) error {
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walkFn := func(path string, fi os.FileInfo, r io.ReadSeeker, err error) error {
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if err != nil {
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// Consider all errors reading the input filesystem as fatal.
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return err
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}
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switch fi.IsDir() {
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case false:
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file := &fileInfo{
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Path: path,
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Name: pathpkg.Base(path),
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ModTime: fi.ModTime().UTC(),
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UncompressedSize: fi.Size(),
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}
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marker := buf.Len()
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// Write CompressedFileInfo.
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err = writeCompressedFileInfo(buf, file, r)
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switch err {
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default:
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return err
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case nil:
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toc.HasCompressedFile = true
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// If compressed file is not smaller than original, revert and write original file.
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case errCompressedNotSmaller:
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_, err = r.Seek(0, io.SeekStart)
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if err != nil {
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return err
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}
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buf.Truncate(marker)
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// Write FileInfo.
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err = writeFileInfo(buf, file, r)
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if err != nil {
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return err
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}
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toc.HasFile = true
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}
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case true:
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entries, err := readDirPaths(fs, path)
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if err != nil {
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return err
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}
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dir := &dirInfo{
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Path: path,
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Name: pathpkg.Base(path),
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ModTime: fi.ModTime().UTC(),
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Entries: entries,
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}
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toc.dirs = append(toc.dirs, dir)
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// Write DirInfo.
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err = t.ExecuteTemplate(buf, "DirInfo", dir)
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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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return nil
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}
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err := vfsutil.WalkFiles(fs, "/", walkFn)
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return err
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}
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// readDirPaths reads the directory named by dirname and returns
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// a sorted list of directory paths.
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func readDirPaths(fs http.FileSystem, dirname string) ([]string, error) {
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fis, err := vfsutil.ReadDir(fs, dirname)
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if err != nil {
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return nil, err
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}
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paths := make([]string, len(fis))
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for i := range fis {
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paths[i] = pathpkg.Join(dirname, fis[i].Name())
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}
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sort.Strings(paths)
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return paths, nil
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}
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// writeCompressedFileInfo writes CompressedFileInfo.
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// It returns errCompressedNotSmaller if compressed file is not smaller than original.
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func writeCompressedFileInfo(w io.Writer, file *fileInfo, r io.Reader) error {
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err := t.ExecuteTemplate(w, "CompressedFileInfo-Before", file)
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if err != nil {
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return err
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}
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sw := &stringWriter{Writer: w}
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gw := gzip.NewWriter(sw)
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_, err = io.Copy(gw, r)
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if err != nil {
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return err
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}
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err = gw.Close()
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if err != nil {
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return err
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}
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if sw.N >= file.UncompressedSize {
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return errCompressedNotSmaller
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}
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err = t.ExecuteTemplate(w, "CompressedFileInfo-After", file)
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return err
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}
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var errCompressedNotSmaller = errors.New("compressed file is not smaller than original")
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// Write FileInfo.
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func writeFileInfo(w io.Writer, file *fileInfo, r io.Reader) error {
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err := t.ExecuteTemplate(w, "FileInfo-Before", file)
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if err != nil {
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return err
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}
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sw := &stringWriter{Writer: w}
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_, err = io.Copy(sw, r)
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if err != nil {
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return err
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}
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err = t.ExecuteTemplate(w, "FileInfo-After", file)
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return err
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}
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var t = template.Must(template.New("").Funcs(template.FuncMap{
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"quote": strconv.Quote,
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"comment": func(s string) (string, error) {
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var buf bytes.Buffer
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cw := &commentWriter{W: &buf}
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_, err := io.WriteString(cw, s)
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if err != nil {
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return "", err
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}
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err = cw.Close()
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return buf.String(), err
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},
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}).Parse(`{{define "Header"}}// Code generated by vfsgen; DO NOT EDIT.
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{{with .BuildTags}}// +build {{.}}
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{{end}}package {{.PackageName}}
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import (
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"bytes"
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"compress/gzip"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"os"
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pathpkg "path"
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"time"
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)
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{{comment .VariableComment}}
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var {{.VariableName}} = func() http.FileSystem {
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fs := vfsgen۰FS{
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{{end}}
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{{define "CompressedFileInfo-Before"}} {{quote .Path}}: &vfsgen۰CompressedFileInfo{
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name: {{quote .Name}},
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modTime: {{template "Time" .ModTime}},
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uncompressedSize: {{.UncompressedSize}},
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{{/* This blank line separating compressedContent is neccessary to prevent potential gofmt issues. See issue #19. */}}
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compressedContent: []byte("{{end}}{{define "CompressedFileInfo-After"}}"),
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},
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{{end}}
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{{define "FileInfo-Before"}} {{quote .Path}}: &vfsgen۰FileInfo{
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name: {{quote .Name}},
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modTime: {{template "Time" .ModTime}},
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content: []byte("{{end}}{{define "FileInfo-After"}}"),
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},
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{{end}}
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{{define "DirInfo"}} {{quote .Path}}: &vfsgen۰DirInfo{
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name: {{quote .Name}},
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modTime: {{template "Time" .ModTime}},
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},
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{{end}}
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{{define "DirEntries"}} }
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{{range .}}{{if .Entries}} fs[{{quote .Path}}].(*vfsgen۰DirInfo).entries = []os.FileInfo{{"{"}}{{range .Entries}}
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fs[{{quote .}}].(os.FileInfo),{{end}}
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}
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{{end}}{{end}}
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return fs
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}()
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{{end}}
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{{define "Trailer"}}
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type vfsgen۰FS map[string]interface{}
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func (fs vfsgen۰FS) Open(path string) (http.File, error) {
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path = pathpkg.Clean("/" + path)
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f, ok := fs[path]
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if !ok {
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return nil, &os.PathError{Op: "open", Path: path, Err: os.ErrNotExist}
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}
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switch f := f.(type) {{"{"}}{{if .HasCompressedFile}}
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case *vfsgen۰CompressedFileInfo:
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gr, err := gzip.NewReader(bytes.NewReader(f.compressedContent))
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if err != nil {
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// This should never happen because we generate the gzip bytes such that they are always valid.
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panic("unexpected error reading own gzip compressed bytes: " + err.Error())
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}
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return &vfsgen۰CompressedFile{
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vfsgen۰CompressedFileInfo: f,
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gr: gr,
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}, nil{{end}}{{if .HasFile}}
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case *vfsgen۰FileInfo:
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return &vfsgen۰File{
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vfsgen۰FileInfo: f,
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Reader: bytes.NewReader(f.content),
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}, nil{{end}}
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case *vfsgen۰DirInfo:
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return &vfsgen۰Dir{
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vfsgen۰DirInfo: f,
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}, nil
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default:
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// This should never happen because we generate only the above types.
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panic(fmt.Sprintf("unexpected type %T", f))
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}
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}
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{{if .HasCompressedFile}}
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// vfsgen۰CompressedFileInfo is a static definition of a gzip compressed file.
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type vfsgen۰CompressedFileInfo struct {
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name string
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modTime time.Time
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compressedContent []byte
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uncompressedSize int64
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}
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func (f *vfsgen۰CompressedFileInfo) Readdir(count int) ([]os.FileInfo, error) {
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return nil, fmt.Errorf("cannot Readdir from file %s", f.name)
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}
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func (f *vfsgen۰CompressedFileInfo) Stat() (os.FileInfo, error) { return f, nil }
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func (f *vfsgen۰CompressedFileInfo) GzipBytes() []byte {
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return f.compressedContent
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}
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func (f *vfsgen۰CompressedFileInfo) Name() string { return f.name }
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func (f *vfsgen۰CompressedFileInfo) Size() int64 { return f.uncompressedSize }
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func (f *vfsgen۰CompressedFileInfo) Mode() os.FileMode { return 0444 }
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func (f *vfsgen۰CompressedFileInfo) ModTime() time.Time { return f.modTime }
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func (f *vfsgen۰CompressedFileInfo) IsDir() bool { return false }
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func (f *vfsgen۰CompressedFileInfo) Sys() interface{} { return nil }
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// vfsgen۰CompressedFile is an opened compressedFile instance.
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type vfsgen۰CompressedFile struct {
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*vfsgen۰CompressedFileInfo
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gr *gzip.Reader
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grPos int64 // Actual gr uncompressed position.
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seekPos int64 // Seek uncompressed position.
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}
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func (f *vfsgen۰CompressedFile) Read(p []byte) (n int, err error) {
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if f.grPos > f.seekPos {
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// Rewind to beginning.
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err = f.gr.Reset(bytes.NewReader(f.compressedContent))
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if err != nil {
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return 0, err
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}
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f.grPos = 0
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}
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if f.grPos < f.seekPos {
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// Fast-forward.
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_, err = io.CopyN(ioutil.Discard, f.gr, f.seekPos-f.grPos)
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if err != nil {
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return 0, err
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}
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f.grPos = f.seekPos
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}
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n, err = f.gr.Read(p)
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f.grPos += int64(n)
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f.seekPos = f.grPos
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return n, err
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}
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func (f *vfsgen۰CompressedFile) Seek(offset int64, whence int) (int64, error) {
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switch whence {
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case io.SeekStart:
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f.seekPos = 0 + offset
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case io.SeekCurrent:
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f.seekPos += offset
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case io.SeekEnd:
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f.seekPos = f.uncompressedSize + offset
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default:
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panic(fmt.Errorf("invalid whence value: %v", whence))
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}
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return f.seekPos, nil
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}
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func (f *vfsgen۰CompressedFile) Close() error {
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return f.gr.Close()
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}
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{{else}}
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// We already imported "compress/gzip" and "io/ioutil", but ended up not using them. Avoid unused import error.
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var _ = gzip.Reader{}
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var _ = ioutil.Discard
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{{end}}{{if .HasFile}}
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// vfsgen۰FileInfo is a static definition of an uncompressed file (because it's not worth gzip compressing).
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type vfsgen۰FileInfo struct {
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name string
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modTime time.Time
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content []byte
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}
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func (f *vfsgen۰FileInfo) Readdir(count int) ([]os.FileInfo, error) {
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return nil, fmt.Errorf("cannot Readdir from file %s", f.name)
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}
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func (f *vfsgen۰FileInfo) Stat() (os.FileInfo, error) { return f, nil }
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func (f *vfsgen۰FileInfo) NotWorthGzipCompressing() {}
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func (f *vfsgen۰FileInfo) Name() string { return f.name }
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func (f *vfsgen۰FileInfo) Size() int64 { return int64(len(f.content)) }
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func (f *vfsgen۰FileInfo) Mode() os.FileMode { return 0444 }
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func (f *vfsgen۰FileInfo) ModTime() time.Time { return f.modTime }
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func (f *vfsgen۰FileInfo) IsDir() bool { return false }
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func (f *vfsgen۰FileInfo) Sys() interface{} { return nil }
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// vfsgen۰File is an opened file instance.
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type vfsgen۰File struct {
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*vfsgen۰FileInfo
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*bytes.Reader
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}
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func (f *vfsgen۰File) Close() error {
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return nil
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}
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{{else if not .HasCompressedFile}}
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// We already imported "bytes", but ended up not using it. Avoid unused import error.
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var _ = bytes.Reader{}
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{{end}}
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// vfsgen۰DirInfo is a static definition of a directory.
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type vfsgen۰DirInfo struct {
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name string
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modTime time.Time
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entries []os.FileInfo
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}
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func (d *vfsgen۰DirInfo) Read([]byte) (int, error) {
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return 0, fmt.Errorf("cannot Read from directory %s", d.name)
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}
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func (d *vfsgen۰DirInfo) Close() error { return nil }
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func (d *vfsgen۰DirInfo) Stat() (os.FileInfo, error) { return d, nil }
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func (d *vfsgen۰DirInfo) Name() string { return d.name }
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func (d *vfsgen۰DirInfo) Size() int64 { return 0 }
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func (d *vfsgen۰DirInfo) Mode() os.FileMode { return 0755 | os.ModeDir }
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func (d *vfsgen۰DirInfo) ModTime() time.Time { return d.modTime }
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func (d *vfsgen۰DirInfo) IsDir() bool { return true }
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func (d *vfsgen۰DirInfo) Sys() interface{} { return nil }
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// vfsgen۰Dir is an opened dir instance.
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type vfsgen۰Dir struct {
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*vfsgen۰DirInfo
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pos int // Position within entries for Seek and Readdir.
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}
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func (d *vfsgen۰Dir) Seek(offset int64, whence int) (int64, error) {
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if offset == 0 && whence == io.SeekStart {
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d.pos = 0
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return 0, nil
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}
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return 0, fmt.Errorf("unsupported Seek in directory %s", d.name)
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}
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func (d *vfsgen۰Dir) Readdir(count int) ([]os.FileInfo, error) {
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if d.pos >= len(d.entries) && count > 0 {
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return nil, io.EOF
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}
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if count <= 0 || count > len(d.entries)-d.pos {
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count = len(d.entries) - d.pos
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}
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e := d.entries[d.pos : d.pos+count]
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d.pos += count
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return e, nil
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}
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{{end}}
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{{define "Time"}}
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{{- if .IsZero -}}
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time.Time{}
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{{- else -}}
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time.Date({{.Year}}, {{printf "%d" .Month}}, {{.Day}}, {{.Hour}}, {{.Minute}}, {{.Second}}, {{.Nanosecond}}, time.UTC)
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{{- end -}}
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{{end}}
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`))
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