mirror of
https://github.com/rclone/rclone.git
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383 lines
11 KiB
Go
383 lines
11 KiB
Go
// Package vfs provides a virtual filing system layer over rclone's
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// native objects.
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//
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// It attempts to behave in a similar way to Go's filing system
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// manipulation code in the os package. The same named function
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// should behave in an identical fashion. The objects also obey Go's
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// standard interfaces.
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//
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// Note that paths don't start or end with /, so the root directory
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// may be referred to as "". However Stat strips slashes so you can
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// use paths with slashes in.
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//
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// It also includes directory caching
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//
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// The vfs package returns Error values to signal precisely which
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// error conditions have ocurred. It may also return general errors
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// it receives. It tries to use os Error values (eg os.ErrExist)
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// where possible.
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package vfs
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import (
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"fmt"
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"os"
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"path"
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"strings"
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"sync/atomic"
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"time"
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"github.com/ncw/rclone/fs"
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"golang.org/x/net/context" // switch to "context" when we stop supporting go1.6
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)
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// DefaultOpt is the default values uses for Opt
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var DefaultOpt = Options{
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NoModTime: false,
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NoChecksum: false,
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NoSeek: false,
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DirCacheTime: 5 * 60 * time.Second,
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PollInterval: time.Minute,
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ReadOnly: false,
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Umask: 0,
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UID: ^uint32(0), // these values instruct WinFSP-FUSE to use the current user
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GID: ^uint32(0), // overriden for non windows in mount_unix.go
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DirPerms: os.FileMode(0777) | os.ModeDir,
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FilePerms: os.FileMode(0666),
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CacheMode: CacheModeOff,
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CacheMaxAge: 3600 * time.Second,
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CachePollInterval: 60 * time.Second,
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}
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// Node represents either a directory (*Dir) or a file (*File)
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type Node interface {
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os.FileInfo
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IsFile() bool
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Inode() uint64
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SetModTime(modTime time.Time) error
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Fsync() error
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Remove() error
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RemoveAll() error
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DirEntry() fs.DirEntry
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VFS() *VFS
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Open(flags int) (Handle, error)
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Truncate(size int64) error
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}
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// Check interfaces
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var (
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_ Node = (*File)(nil)
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_ Node = (*Dir)(nil)
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)
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// Nodes is a slice of Node
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type Nodes []Node
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// Sort functions
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func (ns Nodes) Len() int { return len(ns) }
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func (ns Nodes) Swap(i, j int) { ns[i], ns[j] = ns[j], ns[i] }
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func (ns Nodes) Less(i, j int) bool { return ns[i].DirEntry().Remote() < ns[j].DirEntry().Remote() }
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// Noder represents something which can return a node
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type Noder interface {
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fmt.Stringer
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Node() Node
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}
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// Check interfaces
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var (
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_ Noder = (*File)(nil)
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_ Noder = (*Dir)(nil)
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_ Noder = (*ReadFileHandle)(nil)
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_ Noder = (*WriteFileHandle)(nil)
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_ Noder = (*RWFileHandle)(nil)
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_ Noder = (*DirHandle)(nil)
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)
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// OsFiler is the methods on *os.File
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type OsFiler interface {
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Chdir() error
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Chmod(mode os.FileMode) error
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Chown(uid, gid int) error
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Close() error
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Fd() uintptr
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Name() string
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Read(b []byte) (n int, err error)
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ReadAt(b []byte, off int64) (n int, err error)
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Readdir(n int) ([]os.FileInfo, error)
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Readdirnames(n int) (names []string, err error)
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Seek(offset int64, whence int) (ret int64, err error)
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Stat() (os.FileInfo, error)
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Sync() error
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Truncate(size int64) error
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Write(b []byte) (n int, err error)
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WriteAt(b []byte, off int64) (n int, err error)
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WriteString(s string) (n int, err error)
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}
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// Handle is the interface statisified by open files or directories.
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// It is the methods on *os.File, plus a few more useful for FUSE
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// filingsystems. Not all of them are supported.
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type Handle interface {
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OsFiler
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// Additional methods useful for FUSE filesystems
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Flush() error
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Release() error
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Node() Node
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// Size() int64
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}
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// baseHandle implements all the missing methods
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type baseHandle struct{}
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func (h baseHandle) Chdir() error { return ENOSYS }
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func (h baseHandle) Chmod(mode os.FileMode) error { return ENOSYS }
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func (h baseHandle) Chown(uid, gid int) error { return ENOSYS }
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func (h baseHandle) Close() error { return ENOSYS }
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func (h baseHandle) Fd() uintptr { return 0 }
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func (h baseHandle) Name() string { return "" }
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func (h baseHandle) Read(b []byte) (n int, err error) { return 0, ENOSYS }
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func (h baseHandle) ReadAt(b []byte, off int64) (n int, err error) { return 0, ENOSYS }
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func (h baseHandle) Readdir(n int) ([]os.FileInfo, error) { return nil, ENOSYS }
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func (h baseHandle) Readdirnames(n int) (names []string, err error) { return nil, ENOSYS }
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func (h baseHandle) Seek(offset int64, whence int) (ret int64, err error) { return 0, ENOSYS }
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func (h baseHandle) Stat() (os.FileInfo, error) { return nil, ENOSYS }
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func (h baseHandle) Sync() error { return nil }
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func (h baseHandle) Truncate(size int64) error { return ENOSYS }
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func (h baseHandle) Write(b []byte) (n int, err error) { return 0, ENOSYS }
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func (h baseHandle) WriteAt(b []byte, off int64) (n int, err error) { return 0, ENOSYS }
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func (h baseHandle) WriteString(s string) (n int, err error) { return 0, ENOSYS }
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func (h baseHandle) Flush() (err error) { return ENOSYS }
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func (h baseHandle) Release() (err error) { return ENOSYS }
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func (h baseHandle) Node() Node { return nil }
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//func (h baseHandle) Size() int64 { return 0 }
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// Check interfaces
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var (
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_ OsFiler = (*os.File)(nil)
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_ Handle = (*baseHandle)(nil)
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_ Handle = (*ReadFileHandle)(nil)
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_ Handle = (*WriteFileHandle)(nil)
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_ Handle = (*DirHandle)(nil)
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)
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// VFS represents the top level filing system
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type VFS struct {
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f fs.Fs
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root *Dir
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Opt Options
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cache *cache
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cancel context.CancelFunc
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}
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// Options is options for creating the vfs
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type Options struct {
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NoSeek bool // don't allow seeking if set
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NoChecksum bool // don't check checksums if set
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ReadOnly bool // if set VFS is read only
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NoModTime bool // don't read mod times for files
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DirCacheTime time.Duration // how long to consider directory listing cache valid
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PollInterval time.Duration
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Umask int
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UID uint32
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GID uint32
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DirPerms os.FileMode
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FilePerms os.FileMode
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CacheMode CacheMode
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CacheMaxAge time.Duration
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CachePollInterval time.Duration
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}
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// New creates a new VFS and root directory. If opt is nil, then
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// DefaultOpt will be used
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func New(f fs.Fs, opt *Options) *VFS {
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fsDir := fs.NewDir("", time.Now())
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vfs := &VFS{
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f: f,
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}
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// Make a copy of the options
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if opt != nil {
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vfs.Opt = *opt
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} else {
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vfs.Opt = DefaultOpt
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}
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// Mask the permissions with the umask
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vfs.Opt.DirPerms &= ^os.FileMode(vfs.Opt.Umask)
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vfs.Opt.FilePerms &= ^os.FileMode(vfs.Opt.Umask)
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// Make sure directories are returned as directories
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vfs.Opt.DirPerms |= os.ModeDir
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// Create root directory
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vfs.root = newDir(vfs, f, nil, fsDir)
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// Start polling if required
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if vfs.Opt.PollInterval > 0 {
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if do := vfs.f.Features().DirChangeNotify; do != nil {
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do(vfs.root.ForgetPath, vfs.Opt.PollInterval)
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} else {
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fs.Logf(f, "poll-interval is not supported by this remote")
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}
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}
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// Create the cache
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ctx, cancel := context.WithCancel(context.Background())
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vfs.cancel = cancel
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cache, err := newCache(ctx, f, &vfs.Opt) // FIXME pass on context or get from Opt?
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if err != nil {
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// FIXME
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panic(fmt.Sprintf("failed to create local cache: %v", err))
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}
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vfs.cache = cache
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return vfs
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}
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// Shutdown stops any background go-routines
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func (vfs *VFS) Shutdown() {
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if vfs.cancel != nil {
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vfs.cancel()
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vfs.cancel = nil
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}
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}
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// CleanUp deletes the contents of the cache
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func (vfs *VFS) CleanUp() error {
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return vfs.cache.cleanUp()
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}
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// Root returns the root node
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func (vfs *VFS) Root() (*Dir, error) {
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// fs.Debugf(vfs.f, "Root()")
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return vfs.root, nil
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}
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var inodeCount uint64
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// newInode creates a new unique inode number
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func newInode() (inode uint64) {
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return atomic.AddUint64(&inodeCount, 1)
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}
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// Stat finds the Node by path starting from the root
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//
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// It is the equivalent of os.Stat - Node contains the os.FileInfo
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// interface.
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func (vfs *VFS) Stat(path string) (node Node, err error) {
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path = strings.Trim(path, "/")
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node = vfs.root
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for path != "" {
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i := strings.IndexRune(path, '/')
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var name string
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if i < 0 {
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name, path = path, ""
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} else {
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name, path = path[:i], path[i+1:]
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}
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if name == "" {
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continue
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}
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dir, ok := node.(*Dir)
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if !ok {
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// We need to look in a directory, but found a file
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return nil, ENOENT
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}
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node, err = dir.Stat(name)
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if err != nil {
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return nil, err
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}
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}
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return
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}
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// StatParent finds the parent directory and the leaf name of a path
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func (vfs *VFS) StatParent(name string) (dir *Dir, leaf string, err error) {
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name = strings.Trim(name, "/")
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parent, leaf := path.Split(name)
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node, err := vfs.Stat(parent)
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if err != nil {
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return nil, "", err
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}
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if node.IsFile() {
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return nil, "", os.ErrExist
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}
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dir = node.(*Dir)
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return dir, leaf, nil
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}
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// decodeOpenFlags returns a string representing the open flags
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func decodeOpenFlags(flags int) string {
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var out []string
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rdwrMode := flags & accessModeMask
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switch rdwrMode {
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case os.O_RDONLY:
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out = append(out, "O_RDONLY")
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case os.O_WRONLY:
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out = append(out, "O_WRONLY")
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case os.O_RDWR:
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out = append(out, "O_RDWR")
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default:
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out = append(out, fmt.Sprintf("0x%X", rdwrMode))
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}
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if flags&os.O_APPEND != 0 {
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out = append(out, "O_APPEND")
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}
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if flags&os.O_CREATE != 0 {
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out = append(out, "O_CREATE")
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}
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if flags&os.O_EXCL != 0 {
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out = append(out, "O_EXCL")
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}
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if flags&os.O_SYNC != 0 {
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out = append(out, "O_SYNC")
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}
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if flags&os.O_TRUNC != 0 {
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out = append(out, "O_TRUNC")
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}
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flags &^= accessModeMask | os.O_APPEND | os.O_CREATE | os.O_EXCL | os.O_SYNC | os.O_TRUNC
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if flags != 0 {
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out = append(out, fmt.Sprintf("0x%X", flags))
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}
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return strings.Join(out, "|")
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}
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// OpenFile a file according to the flags and perm provided
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func (vfs *VFS) OpenFile(name string, flags int, perm os.FileMode) (fd Handle, err error) {
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defer fs.Trace(name, "flags=%s, perm=%v", decodeOpenFlags(flags), perm)("fd=%v, err=%v", &fd, &err)
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node, err := vfs.Stat(name)
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if err != nil {
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if err != ENOENT || flags&os.O_CREATE == 0 {
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return nil, err
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}
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// If not found and O_CREATE then create the file
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dir, leaf, err := vfs.StatParent(name)
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if err != nil {
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return nil, err
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}
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node, err = dir.Create(leaf)
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if err != nil {
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return nil, err
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}
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}
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return node.Open(flags)
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}
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// Rename oldName to newName
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func (vfs *VFS) Rename(oldName, newName string) error {
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// find the parent directories
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oldDir, oldLeaf, err := vfs.StatParent(oldName)
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if err != nil {
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return err
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}
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newDir, newLeaf, err := vfs.StatParent(newName)
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if err != nil {
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return err
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}
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err = oldDir.Rename(oldLeaf, newLeaf, newDir)
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if err != nil {
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return err
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}
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return nil
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}
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