161 lines
2.9 KiB
Go
161 lines
2.9 KiB
Go
// Package extract iterates over the contents of common archive formats
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// (zip, tar, tar.gz, 7z, rar) without extracting to disk.
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package extract
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import (
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"archive/tar"
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"archive/zip"
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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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"path/filepath"
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"strings"
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"github.com/bodgit/sevenzip"
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"github.com/nwaples/rardecode/v2"
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)
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type Entry struct {
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Name string
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Data []byte
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}
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type WalkFn func(Entry) error
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// Walk dispatches by extension and calls fn for each file entry.
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func Walk(name string, data []byte, fn WalkFn) error {
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ext := strings.ToLower(filepath.Ext(name))
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switch ext {
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case ".zip":
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return walkZip(data, fn)
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case ".tar":
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return walkTar(bytes.NewReader(data), fn)
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case ".gz", ".tgz":
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return walkTarGz(data, fn)
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case ".7z":
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return walk7z(data, fn)
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case ".rar":
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return walkRar(data, fn)
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}
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return fmt.Errorf("unsupported archive: %s", ext)
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}
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// IsArchive reports whether name has an extension we know how to extract.
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func IsArchive(name string) bool {
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switch strings.ToLower(filepath.Ext(name)) {
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case ".zip", ".tar", ".gz", ".tgz", ".7z", ".rar":
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return true
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}
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return false
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}
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func walkZip(data []byte, fn WalkFn) error {
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r, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
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if err != nil {
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return err
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}
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for _, f := range r.File {
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if f.FileInfo().IsDir() {
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continue
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}
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rc, err := f.Open()
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if err != nil {
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return err
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}
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buf, err := io.ReadAll(rc)
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rc.Close()
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if err != nil {
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return err
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}
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if err := fn(Entry{Name: f.Name, Data: buf}); 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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func walkTar(r io.Reader, fn WalkFn) error {
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tr := tar.NewReader(r)
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for {
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hdr, err := tr.Next()
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if errors.Is(err, io.EOF) {
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return nil
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}
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if err != nil {
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return err
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}
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if hdr.Typeflag != tar.TypeReg {
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continue
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}
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buf, err := io.ReadAll(tr)
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if err != nil {
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return err
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}
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if err := fn(Entry{Name: hdr.Name, Data: buf}); err != nil {
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return err
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}
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}
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}
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func walkTarGz(data []byte, fn WalkFn) error {
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gz, err := gzip.NewReader(bytes.NewReader(data))
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if err != nil {
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return err
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}
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defer gz.Close()
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return walkTar(gz, fn)
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}
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func walk7z(data []byte, fn WalkFn) error {
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r, err := sevenzip.NewReader(bytes.NewReader(data), int64(len(data)))
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if err != nil {
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return err
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}
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for _, f := range r.File {
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if f.FileInfo().IsDir() {
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continue
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}
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rc, err := f.Open()
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if err != nil {
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return err
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}
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buf, err := io.ReadAll(rc)
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rc.Close()
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if err != nil {
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return err
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}
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if err := fn(Entry{Name: f.Name, Data: buf}); 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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func walkRar(data []byte, fn WalkFn) error {
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r, err := rardecode.NewReader(bytes.NewReader(data))
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if err != nil {
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return err
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}
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for {
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hdr, err := r.Next()
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if errors.Is(err, io.EOF) {
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return nil
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}
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if err != nil {
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return err
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}
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if hdr.IsDir {
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continue
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}
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buf, err := io.ReadAll(r)
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if err != nil {
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return err
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}
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if err := fn(Entry{Name: hdr.Name, Data: buf}); err != nil {
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return err
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}
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}
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}
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