138 lines
3.0 KiB
Go
138 lines
3.0 KiB
Go
package sys
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import (
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"os"
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"syscall"
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"github.com/tetratelabs/wazero/internal/fsapi"
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)
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// compile-time check to ensure lazyDir implements fsapi.File.
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var _ fsapi.File = (*lazyDir)(nil)
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type lazyDir struct {
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fsapi.DirFile
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fs fsapi.FS
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f fsapi.File
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}
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// Dev implements the same method as documented on fsapi.File
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func (r *lazyDir) Dev() (uint64, syscall.Errno) {
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if f, ok := r.file(); !ok {
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return 0, syscall.EBADF
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} else {
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return f.Dev()
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}
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}
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// Ino implements the same method as documented on fsapi.File
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func (r *lazyDir) Ino() (fsapi.Ino, syscall.Errno) {
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if f, ok := r.file(); !ok {
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return 0, syscall.EBADF
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} else {
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return f.Ino()
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}
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}
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// IsDir implements the same method as documented on fsapi.File
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func (r *lazyDir) IsDir() (bool, syscall.Errno) {
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// Note: we don't return a constant because we don't know if this is really
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// backed by a dir, until the first call.
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if f, ok := r.file(); !ok {
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return false, syscall.EBADF
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} else {
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return f.IsDir()
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}
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}
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// IsAppend implements the same method as documented on fsapi.File
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func (r *lazyDir) IsAppend() bool {
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return false
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}
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// SetAppend implements the same method as documented on fsapi.File
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func (r *lazyDir) SetAppend(bool) syscall.Errno {
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return syscall.EISDIR
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}
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// Seek implements the same method as documented on fsapi.File
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func (r *lazyDir) Seek(offset int64, whence int) (newOffset int64, errno syscall.Errno) {
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if f, ok := r.file(); !ok {
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return 0, syscall.EBADF
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} else {
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return f.Seek(offset, whence)
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}
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}
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// Stat implements the same method as documented on fsapi.File
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func (r *lazyDir) Stat() (fsapi.Stat_t, syscall.Errno) {
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if f, ok := r.file(); !ok {
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return fsapi.Stat_t{}, syscall.EBADF
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} else {
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return f.Stat()
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}
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}
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// Readdir implements the same method as documented on fsapi.File
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func (r *lazyDir) Readdir(n int) (dirents []fsapi.Dirent, errno syscall.Errno) {
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if f, ok := r.file(); !ok {
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return nil, syscall.EBADF
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} else {
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return f.Readdir(n)
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}
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}
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// Sync implements the same method as documented on fsapi.File
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func (r *lazyDir) Sync() syscall.Errno {
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if f, ok := r.file(); !ok {
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return syscall.EBADF
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} else {
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return f.Sync()
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}
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}
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// Datasync implements the same method as documented on fsapi.File
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func (r *lazyDir) Datasync() syscall.Errno {
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if f, ok := r.file(); !ok {
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return syscall.EBADF
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} else {
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return f.Datasync()
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}
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}
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// Utimens implements the same method as documented on fsapi.File
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func (r *lazyDir) Utimens(times *[2]syscall.Timespec) syscall.Errno {
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if f, ok := r.file(); !ok {
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return syscall.EBADF
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} else {
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return f.Utimens(times)
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}
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}
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// file returns the underlying file or false if it doesn't exist.
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func (r *lazyDir) file() (fsapi.File, bool) {
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if f := r.f; r.f != nil {
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return f, true
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}
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var errno syscall.Errno
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r.f, errno = r.fs.OpenFile(".", os.O_RDONLY, 0)
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switch errno {
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case 0:
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return r.f, true
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case syscall.ENOENT:
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return nil, false
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default:
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panic(errno) // unexpected
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}
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}
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// Close implements fs.File
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func (r *lazyDir) Close() syscall.Errno {
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f := r.f
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if f == nil {
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return 0 // never opened
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}
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return f.Close()
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}
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