332 lines
8.3 KiB
Go
332 lines
8.3 KiB
Go
//go:build windows
|
|
// +build windows
|
|
|
|
package winio
|
|
|
|
import (
|
|
"errors"
|
|
"io"
|
|
"runtime"
|
|
"sync"
|
|
"sync/atomic"
|
|
"syscall"
|
|
"time"
|
|
|
|
"golang.org/x/sys/windows"
|
|
)
|
|
|
|
//sys cancelIoEx(file syscall.Handle, o *syscall.Overlapped) (err error) = CancelIoEx
|
|
//sys createIoCompletionPort(file syscall.Handle, port syscall.Handle, key uintptr, threadCount uint32) (newport syscall.Handle, err error) = CreateIoCompletionPort
|
|
//sys getQueuedCompletionStatus(port syscall.Handle, bytes *uint32, key *uintptr, o **ioOperation, timeout uint32) (err error) = GetQueuedCompletionStatus
|
|
//sys setFileCompletionNotificationModes(h syscall.Handle, flags uint8) (err error) = SetFileCompletionNotificationModes
|
|
//sys wsaGetOverlappedResult(h syscall.Handle, o *syscall.Overlapped, bytes *uint32, wait bool, flags *uint32) (err error) = ws2_32.WSAGetOverlappedResult
|
|
|
|
type atomicBool int32
|
|
|
|
func (b *atomicBool) isSet() bool { return atomic.LoadInt32((*int32)(b)) != 0 }
|
|
func (b *atomicBool) setFalse() { atomic.StoreInt32((*int32)(b), 0) }
|
|
func (b *atomicBool) setTrue() { atomic.StoreInt32((*int32)(b), 1) }
|
|
|
|
//revive:disable-next-line:predeclared Keep "new" to maintain consistency with "atomic" pkg
|
|
func (b *atomicBool) swap(new bool) bool {
|
|
var newInt int32
|
|
if new {
|
|
newInt = 1
|
|
}
|
|
return atomic.SwapInt32((*int32)(b), newInt) == 1
|
|
}
|
|
|
|
var (
|
|
ErrFileClosed = errors.New("file has already been closed")
|
|
ErrTimeout = &timeoutError{}
|
|
)
|
|
|
|
type timeoutError struct{}
|
|
|
|
func (*timeoutError) Error() string { return "i/o timeout" }
|
|
func (*timeoutError) Timeout() bool { return true }
|
|
func (*timeoutError) Temporary() bool { return true }
|
|
|
|
type timeoutChan chan struct{}
|
|
|
|
var ioInitOnce sync.Once
|
|
var ioCompletionPort syscall.Handle
|
|
|
|
// ioResult contains the result of an asynchronous IO operation.
|
|
type ioResult struct {
|
|
bytes uint32
|
|
err error
|
|
}
|
|
|
|
// ioOperation represents an outstanding asynchronous Win32 IO.
|
|
type ioOperation struct {
|
|
o syscall.Overlapped
|
|
ch chan ioResult
|
|
}
|
|
|
|
func initIO() {
|
|
h, err := createIoCompletionPort(syscall.InvalidHandle, 0, 0, 0xffffffff)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
ioCompletionPort = h
|
|
go ioCompletionProcessor(h)
|
|
}
|
|
|
|
// win32File implements Reader, Writer, and Closer on a Win32 handle without blocking in a syscall.
|
|
// It takes ownership of this handle and will close it if it is garbage collected.
|
|
type win32File struct {
|
|
handle syscall.Handle
|
|
wg sync.WaitGroup
|
|
wgLock sync.RWMutex
|
|
closing atomicBool
|
|
socket bool
|
|
readDeadline deadlineHandler
|
|
writeDeadline deadlineHandler
|
|
}
|
|
|
|
type deadlineHandler struct {
|
|
setLock sync.Mutex
|
|
channel timeoutChan
|
|
channelLock sync.RWMutex
|
|
timer *time.Timer
|
|
timedout atomicBool
|
|
}
|
|
|
|
// makeWin32File makes a new win32File from an existing file handle.
|
|
func makeWin32File(h syscall.Handle) (*win32File, error) {
|
|
f := &win32File{handle: h}
|
|
ioInitOnce.Do(initIO)
|
|
_, err := createIoCompletionPort(h, ioCompletionPort, 0, 0xffffffff)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
err = setFileCompletionNotificationModes(h, windows.FILE_SKIP_COMPLETION_PORT_ON_SUCCESS|windows.FILE_SKIP_SET_EVENT_ON_HANDLE)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
f.readDeadline.channel = make(timeoutChan)
|
|
f.writeDeadline.channel = make(timeoutChan)
|
|
return f, nil
|
|
}
|
|
|
|
func MakeOpenFile(h syscall.Handle) (io.ReadWriteCloser, error) {
|
|
// If we return the result of makeWin32File directly, it can result in an
|
|
// interface-wrapped nil, rather than a nil interface value.
|
|
f, err := makeWin32File(h)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return f, nil
|
|
}
|
|
|
|
// closeHandle closes the resources associated with a Win32 handle.
|
|
func (f *win32File) closeHandle() {
|
|
f.wgLock.Lock()
|
|
// Atomically set that we are closing, releasing the resources only once.
|
|
if !f.closing.swap(true) {
|
|
f.wgLock.Unlock()
|
|
// cancel all IO and wait for it to complete
|
|
_ = cancelIoEx(f.handle, nil)
|
|
f.wg.Wait()
|
|
// at this point, no new IO can start
|
|
syscall.Close(f.handle)
|
|
f.handle = 0
|
|
} else {
|
|
f.wgLock.Unlock()
|
|
}
|
|
}
|
|
|
|
// Close closes a win32File.
|
|
func (f *win32File) Close() error {
|
|
f.closeHandle()
|
|
return nil
|
|
}
|
|
|
|
// IsClosed checks if the file has been closed.
|
|
func (f *win32File) IsClosed() bool {
|
|
return f.closing.isSet()
|
|
}
|
|
|
|
// prepareIO prepares for a new IO operation.
|
|
// The caller must call f.wg.Done() when the IO is finished, prior to Close() returning.
|
|
func (f *win32File) prepareIO() (*ioOperation, error) {
|
|
f.wgLock.RLock()
|
|
if f.closing.isSet() {
|
|
f.wgLock.RUnlock()
|
|
return nil, ErrFileClosed
|
|
}
|
|
f.wg.Add(1)
|
|
f.wgLock.RUnlock()
|
|
c := &ioOperation{}
|
|
c.ch = make(chan ioResult)
|
|
return c, nil
|
|
}
|
|
|
|
// ioCompletionProcessor processes completed async IOs forever.
|
|
func ioCompletionProcessor(h syscall.Handle) {
|
|
for {
|
|
var bytes uint32
|
|
var key uintptr
|
|
var op *ioOperation
|
|
err := getQueuedCompletionStatus(h, &bytes, &key, &op, syscall.INFINITE)
|
|
if op == nil {
|
|
panic(err)
|
|
}
|
|
op.ch <- ioResult{bytes, err}
|
|
}
|
|
}
|
|
|
|
// todo: helsaawy - create an asyncIO version that takes a context
|
|
|
|
// asyncIO processes the return value from ReadFile or WriteFile, blocking until
|
|
// the operation has actually completed.
|
|
func (f *win32File) asyncIO(c *ioOperation, d *deadlineHandler, bytes uint32, err error) (int, error) {
|
|
if err != syscall.ERROR_IO_PENDING { //nolint:errorlint // err is Errno
|
|
return int(bytes), err
|
|
}
|
|
|
|
if f.closing.isSet() {
|
|
_ = cancelIoEx(f.handle, &c.o)
|
|
}
|
|
|
|
var timeout timeoutChan
|
|
if d != nil {
|
|
d.channelLock.Lock()
|
|
timeout = d.channel
|
|
d.channelLock.Unlock()
|
|
}
|
|
|
|
var r ioResult
|
|
select {
|
|
case r = <-c.ch:
|
|
err = r.err
|
|
if err == syscall.ERROR_OPERATION_ABORTED { //nolint:errorlint // err is Errno
|
|
if f.closing.isSet() {
|
|
err = ErrFileClosed
|
|
}
|
|
} else if err != nil && f.socket {
|
|
// err is from Win32. Query the overlapped structure to get the winsock error.
|
|
var bytes, flags uint32
|
|
err = wsaGetOverlappedResult(f.handle, &c.o, &bytes, false, &flags)
|
|
}
|
|
case <-timeout:
|
|
_ = cancelIoEx(f.handle, &c.o)
|
|
r = <-c.ch
|
|
err = r.err
|
|
if err == syscall.ERROR_OPERATION_ABORTED { //nolint:errorlint // err is Errno
|
|
err = ErrTimeout
|
|
}
|
|
}
|
|
|
|
// runtime.KeepAlive is needed, as c is passed via native
|
|
// code to ioCompletionProcessor, c must remain alive
|
|
// until the channel read is complete.
|
|
// todo: (de)allocate *ioOperation via win32 heap functions, instead of needing to KeepAlive?
|
|
runtime.KeepAlive(c)
|
|
return int(r.bytes), err
|
|
}
|
|
|
|
// Read reads from a file handle.
|
|
func (f *win32File) Read(b []byte) (int, error) {
|
|
c, err := f.prepareIO()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
defer f.wg.Done()
|
|
|
|
if f.readDeadline.timedout.isSet() {
|
|
return 0, ErrTimeout
|
|
}
|
|
|
|
var bytes uint32
|
|
err = syscall.ReadFile(f.handle, b, &bytes, &c.o)
|
|
n, err := f.asyncIO(c, &f.readDeadline, bytes, err)
|
|
runtime.KeepAlive(b)
|
|
|
|
// Handle EOF conditions.
|
|
if err == nil && n == 0 && len(b) != 0 {
|
|
return 0, io.EOF
|
|
} else if err == syscall.ERROR_BROKEN_PIPE { //nolint:errorlint // err is Errno
|
|
return 0, io.EOF
|
|
} else {
|
|
return n, err
|
|
}
|
|
}
|
|
|
|
// Write writes to a file handle.
|
|
func (f *win32File) Write(b []byte) (int, error) {
|
|
c, err := f.prepareIO()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
defer f.wg.Done()
|
|
|
|
if f.writeDeadline.timedout.isSet() {
|
|
return 0, ErrTimeout
|
|
}
|
|
|
|
var bytes uint32
|
|
err = syscall.WriteFile(f.handle, b, &bytes, &c.o)
|
|
n, err := f.asyncIO(c, &f.writeDeadline, bytes, err)
|
|
runtime.KeepAlive(b)
|
|
return n, err
|
|
}
|
|
|
|
func (f *win32File) SetReadDeadline(deadline time.Time) error {
|
|
return f.readDeadline.set(deadline)
|
|
}
|
|
|
|
func (f *win32File) SetWriteDeadline(deadline time.Time) error {
|
|
return f.writeDeadline.set(deadline)
|
|
}
|
|
|
|
func (f *win32File) Flush() error {
|
|
return syscall.FlushFileBuffers(f.handle)
|
|
}
|
|
|
|
func (f *win32File) Fd() uintptr {
|
|
return uintptr(f.handle)
|
|
}
|
|
|
|
func (d *deadlineHandler) set(deadline time.Time) error {
|
|
d.setLock.Lock()
|
|
defer d.setLock.Unlock()
|
|
|
|
if d.timer != nil {
|
|
if !d.timer.Stop() {
|
|
<-d.channel
|
|
}
|
|
d.timer = nil
|
|
}
|
|
d.timedout.setFalse()
|
|
|
|
select {
|
|
case <-d.channel:
|
|
d.channelLock.Lock()
|
|
d.channel = make(chan struct{})
|
|
d.channelLock.Unlock()
|
|
default:
|
|
}
|
|
|
|
if deadline.IsZero() {
|
|
return nil
|
|
}
|
|
|
|
timeoutIO := func() {
|
|
d.timedout.setTrue()
|
|
close(d.channel)
|
|
}
|
|
|
|
now := time.Now()
|
|
duration := deadline.Sub(now)
|
|
if deadline.After(now) {
|
|
// Deadline is in the future, set a timer to wait
|
|
d.timer = time.AfterFunc(duration, timeoutIO)
|
|
} else {
|
|
// Deadline is in the past. Cancel all pending IO now.
|
|
timeoutIO()
|
|
}
|
|
return nil
|
|
}
|