101 lines
2.7 KiB
Go
101 lines
2.7 KiB
Go
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// SPDX-License-Identifier: MIT
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// SPDX-FileCopyrightText: Copyright (c) 2016 Matthew Holt
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// Code in this file was derived from
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// https://github.com/mholt/archiver/blob/v4.0.0-alpha.8/fs.go
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//
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// These modifications were necessary to allow us to use an already open file
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// with archiver.FileFS.
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package archiverext
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import (
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"io"
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"io/fs"
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"github.com/mholt/archiver/v4"
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)
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// FileFS allows accessing a file on disk using a consistent file system interface.
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// The value should be the path to a regular file, not a directory. This file will
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// be the only entry in the file system and will be at its root. It can be accessed
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// within the file system by the name of "." or the filename.
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//
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// If the file is compressed, set the Compression field so that reads from the
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// file will be transparently decompressed.
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type FileFS struct {
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// File is the compressed file backing the FileFS.
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File fs.File
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// If file is compressed, setting this field will
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// transparently decompress reads.
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Compression archiver.Decompressor
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}
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// Open opens the named file, which must be the file used to create the file system.
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func (f FileFS) Open(name string) (fs.File, error) {
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if err := f.checkName(name, "open"); err != nil {
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return nil, err
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}
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if f.Compression == nil {
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return f.File, nil
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}
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r, err := f.Compression.OpenReader(f.File)
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if err != nil {
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return nil, err
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}
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return compressedFile{f.File, r}, nil
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}
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// ReadDir returns a directory listing with the file as the singular entry.
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func (f FileFS) ReadDir(name string) ([]fs.DirEntry, error) {
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if err := f.checkName(name, "stat"); err != nil {
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return nil, err
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}
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info, err := f.Stat(name)
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if err != nil {
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return nil, err
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}
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return []fs.DirEntry{fs.FileInfoToDirEntry(info)}, nil
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}
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// Stat stats the named file, which must be the file used to create the file system.
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func (f FileFS) Stat(name string) (fs.FileInfo, error) {
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if err := f.checkName(name, "stat"); err != nil {
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return nil, err
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}
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return f.File.Stat()
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}
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func (f FileFS) checkName(name, op string) error {
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if !fs.ValidPath(name) {
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return &fs.PathError{Op: "open", Path: name, Err: fs.ErrInvalid}
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}
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// TODO: we may need better name validation.
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if name != "." {
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return &fs.PathError{Op: op, Path: name, Err: fs.ErrNotExist}
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}
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return nil
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}
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// compressedFile is an fs.File that specially reads
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// from a decompression reader, and which closes both
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// that reader and the underlying file.
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type compressedFile struct {
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fs.File
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decomp io.ReadCloser
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}
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func (cf compressedFile) Read(p []byte) (int, error) {
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return cf.decomp.Read(p)
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}
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func (cf compressedFile) Close() error {
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err := cf.File.Close()
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err2 := cf.decomp.Close()
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if err2 != nil && err == nil {
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err = err2
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}
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return err
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}
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