1 files changed, 219 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/microsoft/go-winio/file.go b/Godeps/_workspace/src/github.com/microsoft/go-winio/file.go
new file mode 100644
index 000000000..fd16f0075
--- /dev/null
+++ b/Godeps/_workspace/src/github.com/microsoft/go-winio/file.go
@@ -0,0 +1,219 @@
+package winio
+
+import (
+	"errors"
+	"io"
+	"runtime"
+	"sync"
+	"syscall"
+	"time"
+)
+
+//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 timeBeginPeriod(period uint32) (n int32) = winmm.timeBeginPeriod
+
+const (
+	cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS = 1
+	cFILE_SKIP_SET_EVENT_ON_HANDLE        = 2
+)
+
+var (
+	ErrFileClosed = errors.New("file has already been closed")
+	ErrTimeout    = &timeoutError{}
+)
+
+type timeoutError struct{}
+
+func (e *timeoutError) Error() string   { return "i/o timeout" }
+func (e *timeoutError) Timeout() bool   { return true }
+func (e *timeoutError) Temporary() bool { return true }
+
+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
+	closing       bool
+	readDeadline  time.Time
+	writeDeadline time.Time
+}
+
+// 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, cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS|cFILE_SKIP_SET_EVENT_ON_HANDLE)
+	if err != nil {
+		return nil, err
+	}
+	runtime.SetFinalizer(f, (*win32File).closeHandle)
+	return f, nil
+}
+
+func MakeOpenFile(h syscall.Handle) (io.ReadWriteCloser, error) {
+	return makeWin32File(h)
+}
+
+// closeHandle closes the resources associated with a Win32 handle
+func (f *win32File) closeHandle() {
+	if !f.closing {
+		// cancel all IO and wait for it to complete
+		f.closing = true
+		cancelIoEx(f.handle, nil)
+		f.wg.Wait()
+		// at this point, no new IO can start
+		syscall.Close(f.handle)
+		f.handle = 0
+	}
+}
+
+// Close closes a win32File.
+func (f *win32File) Close() error {
+	f.closeHandle()
+	runtime.SetFinalizer(f, nil)
+	return nil
+}
+
+// prepareIo prepares for a new IO operation
+func (f *win32File) prepareIo() (*ioOperation, error) {
+	f.wg.Add(1)
+	if f.closing {
+		return nil, ErrFileClosed
+	}
+	c := &ioOperation{}
+	c.ch = make(chan ioResult)
+	return c, nil
+}
+
+// ioCompletionProcessor processes completed async IOs forever
+func ioCompletionProcessor(h syscall.Handle) {
+	// Set the timer resolution to 1. This fixes a performance regression in golang 1.6.
+	timeBeginPeriod(1)
+	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}
+	}
+}
+
+// asyncIo processes the return value from ReadFile or WriteFile, blocking until
+// the operation has actually completed.
+func (f *win32File) asyncIo(c *ioOperation, deadline time.Time, bytes uint32, err error) (int, error) {
+	if err != syscall.ERROR_IO_PENDING {
+		f.wg.Done()
+		return int(bytes), err
+	} else {
+		var r ioResult
+		wait := true
+		timedout := false
+		if f.closing {
+			cancelIoEx(f.handle, &c.o)
+		} else if !deadline.IsZero() {
+			now := time.Now()
+			if !deadline.After(now) {
+				timedout = true
+			} else {
+				timeout := time.After(deadline.Sub(now))
+				select {
+				case r = <-c.ch:
+					wait = false
+				case <-timeout:
+					timedout = true
+				}
+			}
+		}
+		if timedout {
+			cancelIoEx(f.handle, &c.o)
+		}
+		if wait {
+			r = <-c.ch
+		}
+		err = r.err
+		if err == syscall.ERROR_OPERATION_ABORTED {
+			if f.closing {
+				err = ErrFileClosed
+			} else if timedout {
+				err = ErrTimeout
+			}
+		}
+		f.wg.Done()
+		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
+	}
+	var bytes uint32
+	err = syscall.ReadFile(f.handle, b, &bytes, &c.o)
+	n, err := f.asyncIo(c, f.readDeadline, bytes, err)
+
+	// Handle EOF conditions.
+	if err == nil && n == 0 && len(b) != 0 {
+		return 0, io.EOF
+	} else if err == syscall.ERROR_BROKEN_PIPE {
+		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
+	}
+	var bytes uint32
+	err = syscall.WriteFile(f.handle, b, &bytes, &c.o)
+	return f.asyncIo(c, f.writeDeadline, bytes, err)
+}
+
+func (f *win32File) SetReadDeadline(t time.Time) error {
+	f.readDeadline = t
+	return nil
+}
+
+func (f *win32File) SetWriteDeadline(t time.Time) error {
+	f.writeDeadline = t
+	return nil
+}