go reader 源码
golang reader 代码
文件路径：/src/archive/zip/reader.go
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package zip
import (
"bufio"
"encoding/binary"
"errors"
"hash"
"hash/crc32"
"io"
"io/fs"
"os"
"path"
"sort"
"strings"
"sync"
"time"
)
var (
ErrFormat = errors.New("zip: not a valid zip file")
ErrAlgorithm = errors.New("zip: unsupported compression algorithm")
ErrChecksum = errors.New("zip: checksum error")
)
// A Reader serves content from a ZIP archive.
type Reader struct {
r io.ReaderAt
File []*File
Comment string
decompressors map[uint16]Decompressor
// Some JAR files are zip files with a prefix that is a bash script.
// The baseOffset field is the start of the zip file proper.
baseOffset int64
// fileList is a list of files sorted by ename,
// for use by the Open method.
fileListOnce sync.Once
fileList []fileListEntry
}
// A ReadCloser is a Reader that must be closed when no longer needed.
type ReadCloser struct {
f *os.File
Reader
}
// A File is a single file in a ZIP archive.
// The file information is in the embedded FileHeader.
// The file content can be accessed by calling Open.
type File struct {
FileHeader
zip *Reader
zipr io.ReaderAt
headerOffset int64 // includes overall ZIP archive baseOffset
zip64 bool // zip64 extended information extra field presence
}
// OpenReader will open the Zip file specified by name and return a ReadCloser.
func OpenReader(name string) (*ReadCloser, error) {
f, err := os.Open(name)
if err != nil {
return nil, err
}
fi, err := f.Stat()
if err != nil {
f.Close()
return nil, err
}
r := new(ReadCloser)
if err := r.init(f, fi.Size()); err != nil {
f.Close()
return nil, err
}
r.f = f
return r, nil
}
// NewReader returns a new Reader reading from r, which is assumed to
// have the given size in bytes.
func NewReader(r io.ReaderAt, size int64) (*Reader, error) {
if size < 0 {
return nil, errors.New("zip: size cannot be negative")
}
zr := new(Reader)
if err := zr.init(r, size); err != nil {
return nil, err
}
return zr, nil
}
func (z *Reader) init(r io.ReaderAt, size int64) error {
end, baseOffset, err := readDirectoryEnd(r, size)
if err != nil {
return err
}
z.r = r
z.baseOffset = baseOffset
// Since the number of directory records is not validated, it is not
// safe to preallocate z.File without first checking that the specified
// number of files is reasonable, since a malformed archive may
// indicate it contains up to 1 << 128 - 1 files. Since each file has a
// header which will be _at least_ 30 bytes we can safely preallocate
// if (data size / 30) >= end.directoryRecords.
if end.directorySize < uint64(size) && (uint64(size)-end.directorySize)/30 >= end.directoryRecords {
z.File = make([]*File, 0, end.directoryRecords)
}
z.Comment = end.comment
rs := io.NewSectionReader(r, 0, size)
if _, err = rs.Seek(z.baseOffset+int64(end.directoryOffset), io.SeekStart); err != nil {
return err
}
buf := bufio.NewReader(rs)
// The count of files inside a zip is truncated to fit in a uint16.
// Gloss over this by reading headers until we encounter
// a bad one, and then only report an ErrFormat or UnexpectedEOF if
// the file count modulo 65536 is incorrect.
for {
f := &File{zip: z, zipr: r}
err = readDirectoryHeader(f, buf)
// For compatibility with other zip programs,
// if we have a non-zero base offset and can't read
// the first directory header, try again with a zero
// base offset.
if err == ErrFormat && z.baseOffset != 0 && len(z.File) == 0 {
z.baseOffset = 0
if _, err = rs.Seek(int64(end.directoryOffset), io.SeekStart); err != nil {
return err
}
buf.Reset(rs)
continue
}
if err == ErrFormat || err == io.ErrUnexpectedEOF {
break
}
if err != nil {
return err
}
f.headerOffset += z.baseOffset
z.File = append(z.File, f)
}
if uint16(len(z.File)) != uint16(end.directoryRecords) { // only compare 16 bits here
// Return the readDirectoryHeader error if we read
// the wrong number of directory entries.
return err
}
return nil
}
// RegisterDecompressor registers or overrides a custom decompressor for a
// specific method ID. If a decompressor for a given method is not found,
// Reader will default to looking up the decompressor at the package level.
func (z *Reader) RegisterDecompressor(method uint16, dcomp Decompressor) {
if z.decompressors == nil {
z.decompressors = make(map[uint16]Decompressor)
}
z.decompressors[method] = dcomp
}
func (z *Reader) decompressor(method uint16) Decompressor {
dcomp := z.decompressors[method]
if dcomp == nil {
dcomp = decompressor(method)
}
return dcomp
}
// Close closes the Zip file, rendering it unusable for I/O.
func (rc *ReadCloser) Close() error {
return rc.f.Close()
}
// DataOffset returns the offset of the file's possibly-compressed
// data, relative to the beginning of the zip file.
//
// Most callers should instead use Open, which transparently
// decompresses data and verifies checksums.
func (f *File) DataOffset() (offset int64, err error) {
bodyOffset, err := f.findBodyOffset()
if err != nil {
return
}
return f.headerOffset + bodyOffset, nil
}
// Open returns a ReadCloser that provides access to the File's contents.
// Multiple files may be read concurrently.
func (f *File) Open() (io.ReadCloser, error) {
bodyOffset, err := f.findBodyOffset()
if err != nil {
return nil, err
}
size := int64(f.CompressedSize64)
r := io.NewSectionReader(f.zipr, f.headerOffset+bodyOffset, size)
dcomp := f.zip.decompressor(f.Method)
if dcomp == nil {
return nil, ErrAlgorithm
}
var rc io.ReadCloser = dcomp(r)
var desr io.Reader
if f.hasDataDescriptor() {
desr = io.NewSectionReader(f.zipr, f.headerOffset+bodyOffset+size, dataDescriptorLen)
}
rc = &checksumReader{
rc: rc,
hash: crc32.NewIEEE(),
f: f,
desr: desr,
}
return rc, nil
}
// OpenRaw returns a Reader that provides access to the File's contents without
// decompression.
func (f *File) OpenRaw() (io.Reader, error) {
bodyOffset, err := f.findBodyOffset()
if err != nil {
return nil, err
}
r := io.NewSectionReader(f.zipr, f.headerOffset+bodyOffset, int64(f.CompressedSize64))
return r, nil
}
type checksumReader struct {
rc io.ReadCloser
hash hash.Hash32
nread uint64 // number of bytes read so far
f *File
desr io.Reader // if non-nil, where to read the data descriptor
err error // sticky error
}
func (r *checksumReader) Stat() (fs.FileInfo, error) {
return headerFileInfo{&r.f.FileHeader}, nil
}
func (r *checksumReader) Read(b []byte) (n int, err error) {
if r.err != nil {
return 0, r.err
}
n, err = r.rc.Read(b)
r.hash.Write(b[:n])
r.nread += uint64(n)
if r.nread > r.f.UncompressedSize64 {
return 0, ErrFormat
}
if err == nil {
return
}
if err == io.EOF {
if r.nread != r.f.UncompressedSize64 {
return 0, io.ErrUnexpectedEOF
}
if r.desr != nil {
if err1 := readDataDescriptor(r.desr, r.f); err1 != nil {
if err1 == io.EOF {
err = io.ErrUnexpectedEOF
} else {
err = err1
}
} else if r.hash.Sum32() != r.f.CRC32 {
err = ErrChecksum
}
} else {
// If there's not a data descriptor, we still compare
// the CRC32 of what we've read against the file header
// or TOC's CRC32, if it seems like it was set.
if r.f.CRC32 != 0 && r.hash.Sum32() != r.f.CRC32 {
err = ErrChecksum
}
}
}
r.err = err
return
}
func (r *checksumReader) Close() error { return r.rc.Close() }
// findBodyOffset does the minimum work to verify the file has a header
// and returns the file body offset.
func (f *File) findBodyOffset() (int64, error) {
var buf [fileHeaderLen]byte
if _, err := f.zipr.ReadAt(buf[:], f.headerOffset); err != nil {
return 0, err
}
b := readBuf(buf[:])
if sig := b.uint32(); sig != fileHeaderSignature {
return 0, ErrFormat
}
b = b[22:] // skip over most of the header
filenameLen := int(b.uint16())
extraLen := int(b.uint16())
return int64(fileHeaderLen + filenameLen + extraLen), nil
}
// readDirectoryHeader attempts to read a directory header from r.
// It returns io.ErrUnexpectedEOF if it cannot read a complete header,
// and ErrFormat if it doesn't find a valid header signature.
func readDirectoryHeader(f *File, r io.Reader) error {
var buf [directoryHeaderLen]byte
if _, err := io.ReadFull(r, buf[:]); err != nil {
return err
}
b := readBuf(buf[:])
if sig := b.uint32(); sig != directoryHeaderSignature {
return ErrFormat
}
f.CreatorVersion = b.uint16()
f.ReaderVersion = b.uint16()
f.Flags = b.uint16()
f.Method = b.uint16()
f.ModifiedTime = b.uint16()
f.ModifiedDate = b.uint16()
f.CRC32 = b.uint32()
f.CompressedSize = b.uint32()
f.UncompressedSize = b.uint32()
f.CompressedSize64 = uint64(f.CompressedSize)
f.UncompressedSize64 = uint64(f.UncompressedSize)
filenameLen := int(b.uint16())
extraLen := int(b.uint16())
commentLen := int(b.uint16())
b = b[4:] // skipped start disk number and internal attributes (2x uint16)
f.ExternalAttrs = b.uint32()
f.headerOffset = int64(b.uint32())
d := make([]byte, filenameLen+extraLen+commentLen)
if _, err := io.ReadFull(r, d); err != nil {
return err
}
f.Name = string(d[:filenameLen])
f.Extra = d[filenameLen : filenameLen+extraLen]
f.Comment = string(d[filenameLen+extraLen:])
// Determine the character encoding.
utf8Valid1, utf8Require1 := detectUTF8(f.Name)
utf8Valid2, utf8Require2 := detectUTF8(f.Comment)
switch {
case !utf8Valid1 || !utf8Valid2:
// Name and Comment definitely not UTF-8.
f.NonUTF8 = true
case !utf8Require1 && !utf8Require2:
// Name and Comment use only single-byte runes that overlap with UTF-8.
f.NonUTF8 = false
default:
// Might be UTF-8, might be some other encoding; preserve existing flag.
// Some ZIP writers use UTF-8 encoding without setting the UTF-8 flag.
// Since it is impossible to always distinguish valid UTF-8 from some
// other encoding (e.g., GBK or Shift-JIS), we trust the flag.
f.NonUTF8 = f.Flags&0x800 == 0
}
needUSize := f.UncompressedSize == ^uint32(0)
needCSize := f.CompressedSize == ^uint32(0)
needHeaderOffset := f.headerOffset == int64(^uint32(0))
// Best effort to find what we need.
// Other zip authors might not even follow the basic format,
// and we'll just ignore the Extra content in that case.
var modified time.Time
parseExtras:
for extra := readBuf(f.Extra); len(extra) >= 4; { // need at least tag and size
fieldTag := extra.uint16()
fieldSize := int(extra.uint16())
if len(extra) < fieldSize {
break
}
fieldBuf := extra.sub(fieldSize)
switch fieldTag {
case zip64ExtraID:
f.zip64 = true
// update directory values from the zip64 extra block.
// They should only be consulted if the sizes read earlier
// are maxed out.
// See golang.org/issue/13367.
if needUSize {
needUSize = false
if len(fieldBuf) < 8 {
return ErrFormat
}
f.UncompressedSize64 = fieldBuf.uint64()
}
if needCSize {
needCSize = false
if len(fieldBuf) < 8 {
return ErrFormat
}
f.CompressedSize64 = fieldBuf.uint64()
}
if needHeaderOffset {
needHeaderOffset = false
if len(fieldBuf) < 8 {
return ErrFormat
}
f.headerOffset = int64(fieldBuf.uint64())
}
case ntfsExtraID:
if len(fieldBuf) < 4 {
continue parseExtras
}
fieldBuf.uint32() // reserved (ignored)
for len(fieldBuf) >= 4 { // need at least tag and size
attrTag := fieldBuf.uint16()
attrSize := int(fieldBuf.uint16())
if len(fieldBuf) < attrSize {
continue parseExtras
}
attrBuf := fieldBuf.sub(attrSize)
if attrTag != 1 || attrSize != 24 {
continue // Ignore irrelevant attributes
}
const ticksPerSecond = 1e7 // Windows timestamp resolution
ts := int64(attrBuf.uint64()) // ModTime since Windows epoch
secs := int64(ts / ticksPerSecond)
nsecs := (1e9 / ticksPerSecond) * int64(ts%ticksPerSecond)
epoch := time.Date(1601, time.January, 1, 0, 0, 0, 0, time.UTC)
modified = time.Unix(epoch.Unix()+secs, nsecs)
}
case unixExtraID, infoZipUnixExtraID:
if len(fieldBuf) < 8 {
continue parseExtras
}
fieldBuf.uint32() // AcTime (ignored)
ts := int64(fieldBuf.uint32()) // ModTime since Unix epoch
modified = time.Unix(ts, 0)
case extTimeExtraID:
if len(fieldBuf) < 5 || fieldBuf.uint8()&1 == 0 {
continue parseExtras
}
ts := int64(fieldBuf.uint32()) // ModTime since Unix epoch
modified = time.Unix(ts, 0)
}
}
msdosModified := msDosTimeToTime(f.ModifiedDate, f.ModifiedTime)
f.Modified = msdosModified
if !modified.IsZero() {
f.Modified = modified.UTC()
// If legacy MS-DOS timestamps are set, we can use the delta between
// the legacy and extended versions to estimate timezone offset.
//
// A non-UTC timezone is always used (even if offset is zero).
// Thus, FileHeader.Modified.Location() == time.UTC is useful for
// determining whether extended timestamps are present.
// This is necessary for users that need to do additional time
// calculations when dealing with legacy ZIP formats.
if f.ModifiedTime != 0 || f.ModifiedDate != 0 {
f.Modified = modified.In(timeZone(msdosModified.Sub(modified)))
}
}
// Assume that uncompressed size 2³²-1 could plausibly happen in
// an old zip32 file that was sharding inputs into the largest chunks
// possible (or is just malicious; search the web for 42.zip).
// If needUSize is true still, it means we didn't see a zip64 extension.
// As long as the compressed size is not also 2³²-1 (implausible)
// and the header is not also 2³²-1 (equally implausible),
// accept the uncompressed size 2³²-1 as valid.
// If nothing else, this keeps archive/zip working with 42.zip.
_ = needUSize
if needCSize || needHeaderOffset {
return ErrFormat
}
return nil
}
func readDataDescriptor(r io.Reader, f *File) error {
var buf [dataDescriptorLen]byte
// The spec says: "Although not originally assigned a
// signature, the value 0x08074b50 has commonly been adopted
// as a signature value for the data descriptor record.
// Implementers should be aware that ZIP files may be
// encountered with or without this signature marking data
// descriptors and should account for either case when reading
// ZIP files to ensure compatibility."
//
// dataDescriptorLen includes the size of the signature but
// first read just those 4 bytes to see if it exists.
if _, err := io.ReadFull(r, buf[:4]); err != nil {
return err
}
off := 0
maybeSig := readBuf(buf[:4])
if maybeSig.uint32() != dataDescriptorSignature {
// No data descriptor signature. Keep these four
// bytes.
off += 4
}
if _, err := io.ReadFull(r, buf[off:12]); err != nil {
return err
}
b := readBuf(buf[:12])
if b.uint32() != f.CRC32 {
return ErrChecksum
}
// The two sizes that follow here can be either 32 bits or 64 bits
// but the spec is not very clear on this and different
// interpretations has been made causing incompatibilities. We
// already have the sizes from the central directory so we can
// just ignore these.
return nil
}
func readDirectoryEnd(r io.ReaderAt, size int64) (dir *directoryEnd, baseOffset int64, err error) {
// look for directoryEndSignature in the last 1k, then in the last 65k
var buf []byte
var directoryEndOffset int64
for i, bLen := range []int64{1024, 65 * 1024} {
if bLen > size {
bLen = size
}
buf = make([]byte, int(bLen))
if _, err := r.ReadAt(buf, size-bLen); err != nil && err != io.EOF {
return nil, 0, err
}
if p := findSignatureInBlock(buf); p >= 0 {
buf = buf[p:]
directoryEndOffset = size - bLen + int64(p)
break
}
if i == 1 || bLen == size {
return nil, 0, ErrFormat
}
}
// read header into struct
b := readBuf(buf[4:]) // skip signature
d := &directoryEnd{
diskNbr: uint32(b.uint16()),
dirDiskNbr: uint32(b.uint16()),
dirRecordsThisDisk: uint64(b.uint16()),
directoryRecords: uint64(b.uint16()),
directorySize: uint64(b.uint32()),
directoryOffset: uint64(b.uint32()),
commentLen: b.uint16(),
}
l := int(d.commentLen)
if l > len(b) {
return nil, 0, errors.New("zip: invalid comment length")
}
d.comment = string(b[:l])
// These values mean that the file can be a zip64 file
if d.directoryRecords == 0xffff || d.directorySize == 0xffff || d.directoryOffset == 0xffffffff {
p, err := findDirectory64End(r, directoryEndOffset)
if err == nil && p >= 0 {
directoryEndOffset = p
err = readDirectory64End(r, p, d)
}
if err != nil {
return nil, 0, err
}
}
baseOffset = directoryEndOffset - int64(d.directorySize) - int64(d.directoryOffset)
// Make sure directoryOffset points to somewhere in our file.
if o := baseOffset + int64(d.directoryOffset); o < 0 || o >= size {
return nil, 0, ErrFormat
}
return d, baseOffset, nil
}
// findDirectory64End tries to read the zip64 locator just before the
// directory end and returns the offset of the zip64 directory end if
// found.
func findDirectory64End(r io.ReaderAt, directoryEndOffset int64) (int64, error) {
locOffset := directoryEndOffset - directory64LocLen
if locOffset < 0 {
return -1, nil // no need to look for a header outside the file
}
buf := make([]byte, directory64LocLen)
if _, err := r.ReadAt(buf, locOffset); err != nil {
return -1, err
}
b := readBuf(buf)
if sig := b.uint32(); sig != directory64LocSignature {
return -1, nil
}
if b.uint32() != 0 { // number of the disk with the start of the zip64 end of central directory
return -1, nil // the file is not a valid zip64-file
}
p := b.uint64() // relative offset of the zip64 end of central directory record
if b.uint32() != 1 { // total number of disks
return -1, nil // the file is not a valid zip64-file
}
return int64(p), nil
}
// readDirectory64End reads the zip64 directory end and updates the
// directory end with the zip64 directory end values.
func readDirectory64End(r io.ReaderAt, offset int64, d *directoryEnd) (err error) {
buf := make([]byte, directory64EndLen)
if _, err := r.ReadAt(buf, offset); err != nil {
return err
}
b := readBuf(buf)
if sig := b.uint32(); sig != directory64EndSignature {
return ErrFormat
}
b = b[12:] // skip dir size, version and version needed (uint64 + 2x uint16)
d.diskNbr = b.uint32() // number of this disk
d.dirDiskNbr = b.uint32() // number of the disk with the start of the central directory
d.dirRecordsThisDisk = b.uint64() // total number of entries in the central directory on this disk
d.directoryRecords = b.uint64() // total number of entries in the central directory
d.directorySize = b.uint64() // size of the central directory
d.directoryOffset = b.uint64() // offset of start of central directory with respect to the starting disk number
return nil
}
func findSignatureInBlock(b []byte) int {
for i := len(b) - directoryEndLen; i >= 0; i-- {
// defined from directoryEndSignature in struct.go
if b[i] == 'P' && b[i+1] == 'K' && b[i+2] == 0x05 && b[i+3] == 0x06 {
// n is length of comment
n := int(b[i+directoryEndLen-2]) | int(b[i+directoryEndLen-1])<<8
if n+directoryEndLen+i <= len(b) {
return i
}
}
}
return -1
}
type readBuf []byte
func (b *readBuf) uint8() uint8 {
v := (*b)[0]
*b = (*b)[1:]
return v
}
func (b *readBuf) uint16() uint16 {
v := binary.LittleEndian.Uint16(*b)
*b = (*b)[2:]
return v
}
func (b *readBuf) uint32() uint32 {
v := binary.LittleEndian.Uint32(*b)
*b = (*b)[4:]
return v
}
func (b *readBuf) uint64() uint64 {
v := binary.LittleEndian.Uint64(*b)
*b = (*b)[8:]
return v
}
func (b *readBuf) sub(n int) readBuf {
b2 := (*b)[:n]
*b = (*b)[n:]
return b2
}
// A fileListEntry is a File and its ename.
// If file == nil, the fileListEntry describes a directory without metadata.
type fileListEntry struct {
name string
file *File
isDir bool
isDup bool
}
type fileInfoDirEntry interface {
fs.FileInfo
fs.DirEntry
}
func (e *fileListEntry) stat() (fileInfoDirEntry, error) {
if e.isDup {
return nil, errors.New(e.name + ": duplicate entries in zip file")
}
if !e.isDir {
return headerFileInfo{&e.file.FileHeader}, nil
}
return e, nil
}
// Only used for directories.
func (f *fileListEntry) Name() string { _, elem, _ := split(f.name); return elem }
func (f *fileListEntry) Size() int64 { return 0 }
func (f *fileListEntry) Mode() fs.FileMode { return fs.ModeDir | 0555 }
func (f *fileListEntry) Type() fs.FileMode { return fs.ModeDir }
func (f *fileListEntry) IsDir() bool { return true }
func (f *fileListEntry) Sys() any { return nil }
func (f *fileListEntry) ModTime() time.Time {
if f.file == nil {
return time.Time{}
}
return f.file.FileHeader.Modified.UTC()
}
func (f *fileListEntry) Info() (fs.FileInfo, error) { return f, nil }
// toValidName coerces name to be a valid name for fs.FS.Open.
func toValidName(name string) string {
name = strings.ReplaceAll(name, `\`, `/`)
p := path.Clean(name)
if strings.HasPrefix(p, "/") {
p = p[len("/"):]
}
for strings.HasPrefix(p, "../") {
p = p[len("../"):]
}
return p
}
func (r *Reader) initFileList() {
r.fileListOnce.Do(func() {
// files and knownDirs map from a file/directory name
// to an index into the r.fileList entry that we are
// building. They are used to mark duplicate entries.
files := make(map[string]int)
knownDirs := make(map[string]int)
// dirs[name] is true if name is known to be a directory,
// because it appears as a prefix in a path.
dirs := make(map[string]bool)
for _, file := range r.File {
isDir := len(file.Name) > 0 && file.Name[len(file.Name)-1] == '/'
name := toValidName(file.Name)
if name == "" {
continue
}
if idx, ok := files[name]; ok {
r.fileList[idx].isDup = true
continue
}
if idx, ok := knownDirs[name]; ok {
r.fileList[idx].isDup = true
continue
}
for dir := path.Dir(name); dir != "."; dir = path.Dir(dir) {
dirs[dir] = true
}
idx := len(r.fileList)
entry := fileListEntry{
name: name,
file: file,
isDir: isDir,
}
r.fileList = append(r.fileList, entry)
if isDir {
knownDirs[name] = idx
} else {
files[name] = idx
}
}
for dir := range dirs {
if _, ok := knownDirs[dir]; !ok {
if idx, ok := files[dir]; ok {
r.fileList[idx].isDup = true
} else {
entry := fileListEntry{
name: dir,
file: nil,
isDir: true,
}
r.fileList = append(r.fileList, entry)
}
}
}
sort.Slice(r.fileList, func(i, j int) bool { return fileEntryLess(r.fileList[i].name, r.fileList[j].name) })
})
}
func fileEntryLess(x, y string) bool {
xdir, xelem, _ := split(x)
ydir, yelem, _ := split(y)
return xdir < ydir || xdir == ydir && xelem < yelem
}
// Open opens the named file in the ZIP archive,
// using the semantics of fs.FS.Open:
// paths are always slash separated, with no
// leading / or ../ elements.
func (r *Reader) Open(name string) (fs.File, error) {
r.initFileList()
if !fs.ValidPath(name) {
return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrInvalid}
}
e := r.openLookup(name)
if e == nil {
return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrNotExist}
}
if e.isDir {
return &openDir{e, r.openReadDir(name), 0}, nil
}
rc, err := e.file.Open()
if err != nil {
return nil, err
}
return rc.(fs.File), nil
}
func split(name string) (dir, elem string, isDir bool) {
if len(name) > 0 && name[len(name)-1] == '/' {
isDir = true
name = name[:len(name)-1]
}
i := len(name) - 1
for i >= 0 && name[i] != '/' {
i--
}
if i < 0 {
return ".", name, isDir
}
return name[:i], name[i+1:], isDir
}
var dotFile = &fileListEntry{name: "./", isDir: true}
func (r *Reader) openLookup(name string) *fileListEntry {
if name == "." {
return dotFile
}
dir, elem, _ := split(name)
files := r.fileList
i := sort.Search(len(files), func(i int) bool {
idir, ielem, _ := split(files[i].name)
return idir > dir || idir == dir && ielem >= elem
})
if i < len(files) {
fname := files[i].name
if fname == name || len(fname) == len(name)+1 && fname[len(name)] == '/' && fname[:len(name)] == name {
return &files[i]
}
}
return nil
}
func (r *Reader) openReadDir(dir string) []fileListEntry {
files := r.fileList
i := sort.Search(len(files), func(i int) bool {
idir, _, _ := split(files[i].name)
return idir >= dir
})
j := sort.Search(len(files), func(j int) bool {
jdir, _, _ := split(files[j].name)
return jdir > dir
})
return files[i:j]
}
type openDir struct {
e *fileListEntry
files []fileListEntry
offset int
}
func (d *openDir) Close() error { return nil }
func (d *openDir) Stat() (fs.FileInfo, error) { return d.e.stat() }
func (d *openDir) Read([]byte) (int, error) {
return 0, &fs.PathError{Op: "read", Path: d.e.name, Err: errors.New("is a directory")}
}
func (d *openDir) ReadDir(count int) ([]fs.DirEntry, error) {
n := len(d.files) - d.offset
if count > 0 && n > count {
n = count
}
if n == 0 {
if count <= 0 {
return nil, nil
}
return nil, io.EOF
}
list := make([]fs.DirEntry, n)
for i := range list {
s, err := d.files[d.offset+i].stat()
if err != nil {
return nil, err
}
list[i] = s
}
d.offset += n
return list, nil
}
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