gotosocial/vendor/github.com/tetratelabs/wazero/internal/sys/lazy.go
kim 1e7b32490d
[experiment] add alternative wasm sqlite3 implementation available via build-tag ()
This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).
2024-05-27 17:46:15 +02:00

151 lines
3.8 KiB
Go

package sys
import (
experimentalsys "github.com/tetratelabs/wazero/experimental/sys"
"github.com/tetratelabs/wazero/internal/fsapi"
"github.com/tetratelabs/wazero/sys"
)
// compile-time check to ensure lazyDir implements sys.File.
var _ experimentalsys.File = (*lazyDir)(nil)
type lazyDir struct {
experimentalsys.DirFile
fs experimentalsys.FS
f experimentalsys.File
}
// Dev implements the same method as documented on sys.File
func (d *lazyDir) Dev() (uint64, experimentalsys.Errno) {
if f, ok := d.file(); !ok {
return 0, experimentalsys.EBADF
} else {
return f.Dev()
}
}
// Ino implements the same method as documented on sys.File
func (d *lazyDir) Ino() (sys.Inode, experimentalsys.Errno) {
if f, ok := d.file(); !ok {
return 0, experimentalsys.EBADF
} else {
return f.Ino()
}
}
// IsDir implements the same method as documented on sys.File
func (d *lazyDir) IsDir() (bool, experimentalsys.Errno) {
// Note: we don't return a constant because we don't know if this is really
// backed by a dir, until the first call.
if f, ok := d.file(); !ok {
return false, experimentalsys.EBADF
} else {
return f.IsDir()
}
}
// IsAppend implements the same method as documented on sys.File
func (d *lazyDir) IsAppend() bool {
return false
}
// SetAppend implements the same method as documented on sys.File
func (d *lazyDir) SetAppend(bool) experimentalsys.Errno {
return experimentalsys.EISDIR
}
// Seek implements the same method as documented on sys.File
func (d *lazyDir) Seek(offset int64, whence int) (newOffset int64, errno experimentalsys.Errno) {
if f, ok := d.file(); !ok {
return 0, experimentalsys.EBADF
} else {
return f.Seek(offset, whence)
}
}
// Stat implements the same method as documented on sys.File
func (d *lazyDir) Stat() (sys.Stat_t, experimentalsys.Errno) {
if f, ok := d.file(); !ok {
return sys.Stat_t{}, experimentalsys.EBADF
} else {
return f.Stat()
}
}
// Readdir implements the same method as documented on sys.File
func (d *lazyDir) Readdir(n int) (dirents []experimentalsys.Dirent, errno experimentalsys.Errno) {
if f, ok := d.file(); !ok {
return nil, experimentalsys.EBADF
} else {
return f.Readdir(n)
}
}
// Sync implements the same method as documented on sys.File
func (d *lazyDir) Sync() experimentalsys.Errno {
if f, ok := d.file(); !ok {
return experimentalsys.EBADF
} else {
return f.Sync()
}
}
// Datasync implements the same method as documented on sys.File
func (d *lazyDir) Datasync() experimentalsys.Errno {
if f, ok := d.file(); !ok {
return experimentalsys.EBADF
} else {
return f.Datasync()
}
}
// Utimens implements the same method as documented on sys.File
func (d *lazyDir) Utimens(atim, mtim int64) experimentalsys.Errno {
if f, ok := d.file(); !ok {
return experimentalsys.EBADF
} else {
return f.Utimens(atim, mtim)
}
}
// file returns the underlying file or false if it doesn't exist.
func (d *lazyDir) file() (experimentalsys.File, bool) {
if f := d.f; d.f != nil {
return f, true
}
var errno experimentalsys.Errno
d.f, errno = d.fs.OpenFile(".", experimentalsys.O_RDONLY, 0)
switch errno {
case 0:
return d.f, true
case experimentalsys.ENOENT:
return nil, false
default:
panic(errno) // unexpected
}
}
// Close implements fs.File
func (d *lazyDir) Close() experimentalsys.Errno {
f := d.f
if f == nil {
return 0 // never opened
}
return f.Close()
}
// IsNonblock implements the same method as documented on fsapi.File
func (d *lazyDir) IsNonblock() bool {
return false
}
// SetNonblock implements the same method as documented on fsapi.File
func (d *lazyDir) SetNonblock(bool) experimentalsys.Errno {
return experimentalsys.EISDIR
}
// Poll implements the same method as documented on fsapi.File
func (d *lazyDir) Poll(fsapi.Pflag, int32) (ready bool, errno experimentalsys.Errno) {
return false, experimentalsys.ENOSYS
}