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joint.go
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joint.go
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package joint
import (
"errors"
"io"
"io/fs"
"path"
"sort"
"strings"
"sync"
"time"
)
// RFile combines fs.File interface and io.Seeker interface.
type RFile interface {
io.Reader
io.ReaderAt
io.Seeker
fs.File
}
// FileInfo inherits fs.FileInfo and provide IsDir that returns
// true for ISO-disk files. Has IsRealDir that provide value
// from inherited fs.FileInfo.
type FileInfo interface {
fs.FileInfo
IsRealDir() bool // returns real file state representation
}
// Joint describes interface with joint to some file system provider.
type Joint interface {
Make(Joint, string) error // establish connection to file system provider
Cleanup() error // close connection to file system provider
Busy() bool // file is opened
fs.FS // open file with local file path
io.Closer // close local file
Size() (int64, error) // helps to make io.SectionReader
fs.ReadDirFile // read directory pointed by local file path
RFile
}
// MakeJoint creates joint with all subsequent chain of joints.
// Please note that folders with .iso extension and non ISO-images
// with .iso extension will cause an error.
func MakeJoint(fullpath string) (j Joint, err error) {
var addr, fpath, is = SplitUrl(fullpath)
if HasFoldPrefix(fullpath, "ftp://") {
j = &FtpJoint{}
if err = j.Make(nil, addr); err != nil {
return
}
} else if HasFoldPrefix(fullpath, "sftp://") {
j = &SftpJoint{}
if err = j.Make(nil, addr); err != nil {
return
}
} else if HasFoldPrefix(fullpath, "http://") || HasFoldPrefix(fullpath, "https://") {
var root, ok = FindDavRoot(addr, fpath)
if !ok {
err = fs.ErrNotExist
return
}
fpath = fpath[len(root)-1:]
j = &DavJoint{}
if err = j.Make(nil, addr+root); err != nil {
return
}
} else if !is {
j = &SysJoint{dir: addr}
} else {
err = fs.ErrNotExist
return
}
var jpos = 0
for {
var p1 = strings.Index(fpath[jpos:], ".iso/")
var p2 = strings.Index(fpath[jpos:], ".ISO/")
if p1 == p2 { // p1 == -1 && p2 == -1
break
}
var p int
if p1 == -1 {
p = p2
} else if p2 == -1 {
p = p1
} else {
p = min(p1, p2)
}
var key = fpath[:p+4]
var jiso = &IsoJoint{}
if err = jiso.Make(j, key); err != nil {
return
}
j, jpos = jiso, p+5
}
if IsTypeIso(fpath[jpos:]) {
var key = fpath[jpos:]
var jiso = &IsoJoint{}
if err = jiso.Make(j, key); err != nil {
return
}
j = jiso
}
return
}
// JointFileInfo have additional IsRealDir, which points real file representation.
type JointFileInfo interface {
fs.FileInfo
IsRealDir() bool
}
// fileinfo is wrapper around inherited fs.FileInfo to provide derived IsDir.
type fileinfo struct {
fs.FileInfo
}
// Hack for gowebdav.File on case if it fill `path` field and
// does not fill `name` field.
func (fi fileinfo) Name() (name string) {
type pather interface {
Path() string
}
if name = fi.FileInfo.Name(); name == "" {
if pi, ok := fi.FileInfo.(pather); ok {
if p := pi.Path(); p != "" {
name = path.Base(p)
}
}
}
return
}
func (fi fileinfo) Mode() fs.FileMode {
var mode = fi.FileInfo.Mode()
if mode.IsRegular() && IsTypeIso(fi.Name()) {
mode |= fs.ModeDir
}
return mode
}
func (fi fileinfo) IsDir() bool {
return fi.FileInfo.IsDir() || IsTypeIso(fi.Name())
}
func (fi fileinfo) IsRealDir() bool {
return fi.FileInfo.IsDir()
}
func (fi fileinfo) Type() fs.FileMode {
return fi.FileInfo.Mode().Type()
}
// Info provided for fs.DirEntry compatibility and returns object itself.
func (fi fileinfo) Info() (fs.FileInfo, error) {
return fi, nil
}
func (fi fileinfo) String() string {
return fs.FormatDirEntry(fi)
}
// ToFileInfo converts base fs.FileInfo to FileInfo that compatible both
// with fs.FileInfo and with fs.DirEntry interface and have derived IsDir.
func ToFileInfo(fi fs.FileInfo) FileInfo {
if fi == nil {
return nil
}
return fileinfo{fi}
}
// ToDirEntry returns FileInfo that compatible with fs.DirEntry interface,
// and have derived IsDir.
func ToDirEntry(fi fs.FileInfo) fs.DirEntry {
if fi == nil {
return nil
}
return fileinfo{fi}
}
// JointWrap helps to return joint into cache after Close-call.
// It has pointer to JointCache that it binded to.
type JointWrap struct {
jc *JointCache
Joint
}
// GetCache returns binded cache.
func (jw JointWrap) GetCache() *JointCache {
return jw.jc
}
// Close calls inherited Close-function and puts joint into binded cache.
func (jw JointWrap) Close() error {
var err = jw.Joint.Close()
if jw.jc != nil {
jw.jc.Put(jw)
}
return err
}
type Config struct {
// Timeout to establish connection to FTP-server.
DialTimeout time.Duration `json:"dial-timeout" yaml:"dial-timeout" xml:"dial-timeout"`
// Expiration duration to keep opened iso-disk structures in cache from last access to it.
DiskCacheExpire time.Duration `json:"disk-cache-expire" yaml:"disk-cache-expire" xml:"disk-cache-expire"`
}
// Cfg is singleton with timeouts settings for all joints.
var Cfg = Config{
DialTimeout: 5 * time.Second,
DiskCacheExpire: 2 * time.Minute,
}
// JointCache implements cache with opened joints to some file system resource.
type JointCache struct {
key string
cache []Joint
expire []*time.Timer
mux sync.Mutex
}
func NewJointCache(key string) *JointCache {
return &JointCache{
key: key,
}
}
// Key is the base address or path for cache file system.
func (jc *JointCache) Key() string {
return jc.key
}
// Open implements fs.FS interface,
// and returns file that can be casted to joint wrapper.
// Note that internal ISO-files are considered as directories and it should
// be provided another JointCache to work with their file system.
// Use JointPool on this case.
func (jc *JointCache) Open(fpath string) (f fs.File, err error) {
var jw JointWrap
if jw, err = jc.Get(); err != nil {
return
}
if _, err = jw.Open(fpath); err != nil {
if errors.Is(err, fs.ErrNotExist) {
jc.Put(jw) // reuse joint
} else if !errors.Is(err, fs.ErrExist) { // not already opened
jw.Cleanup() // drop the joint
}
return
}
f = jw // put joint back to cache after Close
return
}
// Stat implements fs.StatFS interface.
func (jc *JointCache) Stat(fpath string) (fi fs.FileInfo, err error) {
var f fs.File
if f, err = jc.Open(fpath); err != nil {
return
}
defer f.Close()
return f.Stat()
}
// ReadDir implements fs.ReadDirFS interface.
func (jc *JointCache) ReadDir(fpath string) (list []fs.DirEntry, err error) {
var f fs.File
if f, err = jc.Open(fpath); err != nil {
return
}
defer f.Close()
list, err = f.(Joint).ReadDir(-1)
sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
return
}
// Count is number of free joints in cache for one key path.
func (jc *JointCache) Count() int {
jc.mux.Lock()
defer jc.mux.Unlock()
return len(jc.cache)
}
// Close performs close-call to all cached disk joints.
func (jc *JointCache) Close() (err error) {
jc.mux.Lock()
defer jc.mux.Unlock()
for _, t := range jc.expire {
t.Stop()
}
jc.expire = nil
var errs = make([]error, len(jc.cache))
for i, j := range jc.cache {
errs[i] = j.Cleanup()
}
jc.cache = nil
return errors.Join(errs...)
}
// Checks whether it is contained joint in cache.
func (jc *JointCache) Has(j Joint) bool {
if jw, ok := j.(JointWrap); ok {
j = jw.Joint // strip wrapper to avoid overlapping
}
jc.mux.Lock()
defer jc.mux.Unlock()
for _, f := range jc.cache {
if f == j {
return true
}
}
return false
}
// Pop retrieves cached disk joint, and returns ok if it has.
func (jc *JointCache) Pop() (jw JointWrap, ok bool) {
jc.mux.Lock()
defer jc.mux.Unlock()
var l = len(jc.cache)
if l > 0 {
jc.expire[0].Stop()
copy(jc.expire, jc.expire[1:])
jc.expire = jc.expire[:l-1]
jw.Joint = jc.cache[0]
jw.jc = jc // ensure that jc is owned while jw is outside of cache
copy(jc.cache, jc.cache[1:])
jc.cache = jc.cache[:l-1]
ok = true
}
return
}
// Get retrieves cached disk joint, or makes new one.
func (jc *JointCache) Get() (jw JointWrap, err error) {
jw, ok := jc.Pop()
if !ok {
if jw.Joint, err = MakeJoint(jc.key); err != nil {
return
}
jw.jc = jc // ensure that jc is owned while jw is outside of cache
}
return
}
// Put disk joint to cache.
func (jc *JointCache) Put(j Joint) {
if jw, ok := j.(JointWrap); ok {
j = jw.Joint // strip wrapper to avoid overlapping
}
jc.mux.Lock()
defer jc.mux.Unlock()
for _, f := range jc.cache { // ensure that joint does not present
if f == j {
return
}
}
jc.cache = append(jc.cache, j)
jc.expire = append(jc.expire, time.AfterFunc(Cfg.DiskCacheExpire, func() {
if jw, ok := jc.Pop(); ok {
jw.Joint.Cleanup()
}
}))
}
// Eject joint from the cache.
func (jc *JointCache) Eject(j Joint) bool {
if jw, ok := j.(JointWrap); ok {
j = jw.Joint // strip wrapper to avoid overlapping
}
jc.mux.Lock()
defer jc.mux.Unlock()
for i, f := range jc.cache {
if f == j {
jc.expire[i].Stop()
jc.expire = append(jc.expire[:i], jc.expire[i+1:]...)
jc.cache = append(jc.cache[:i], jc.cache[i+1:]...)
return true
}
}
return false
}