Refactor pkg/term package for Windows tty support

Signed-off-by: John Gossman <johngos@microsoft.com>

term/console_windows.go

@@ -0,0 +1,87 @@
+// +build windows
+
+package term
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	// Consts for Get/SetConsoleMode function
+	// see http://msdn.microsoft.com/en-us/library/windows/desktop/ms683167(v=vs.85).aspx
+	ENABLE_ECHO_INPUT      = 0x0004
+	ENABLE_INSERT_MODE     = 0x0020
+	ENABLE_LINE_INPUT      = 0x0002
+	ENABLE_MOUSE_INPUT     = 0x0010
+	ENABLE_PROCESSED_INPUT = 0x0001
+	ENABLE_QUICK_EDIT_MODE = 0x0040
+	ENABLE_WINDOW_INPUT    = 0x0008
+	// If parameter is a screen buffer handle, additional values
+	ENABLE_PROCESSED_OUTPUT   = 0x0001
+	ENABLE_WRAP_AT_EOL_OUTPUT = 0x0002
+)
+
+var kernel32DLL = syscall.NewLazyDLL("kernel32.dll")
+
+var (
+	setConsoleModeProc             = kernel32DLL.NewProc("SetConsoleMode")
+	getConsoleScreenBufferInfoProc = kernel32DLL.NewProc("GetConsoleScreenBufferInfo")
+)
+
+func GetConsoleMode(fileDesc uintptr) (uint32, error) {
+	var mode uint32
+	err := syscall.GetConsoleMode(syscall.Handle(fileDesc), &mode)
+	return mode, err
+}
+
+func SetConsoleMode(fileDesc uintptr, mode uint32) error {
+	r, _, err := setConsoleModeProc.Call(fileDesc, uintptr(mode), 0)
+	if r == 0 {
+		if err != nil {
+			return err
+		}
+		return syscall.EINVAL
+	}
+	return nil
+}
+
+// types for calling GetConsoleScreenBufferInfo
+// see http://msdn.microsoft.com/en-us/library/windows/desktop/ms682093(v=vs.85).aspx
+type (
+	SHORT int16
+
+	SMALL_RECT struct {
+		Left   SHORT
+		Top    SHORT
+		Right  SHORT
+		Bottom SHORT
+	}
+
+	COORD struct {
+		X SHORT
+		Y SHORT
+	}
+
+	WORD uint16
+
+	CONSOLE_SCREEN_BUFFER_INFO struct {
+		dwSize              COORD
+		dwCursorPosition    COORD
+		wAttributes         WORD
+		srWindow            SMALL_RECT
+		dwMaximumWindowSize COORD
+	}
+)
+
+func GetConsoleScreenBufferInfo(fileDesc uintptr) (*CONSOLE_SCREEN_BUFFER_INFO, error) {
+	var info CONSOLE_SCREEN_BUFFER_INFO
+	r, _, err := getConsoleScreenBufferInfoProc.Call(uintptr(fileDesc), uintptr(unsafe.Pointer(&info)), 0)
+	if r == 0 {
+		if err != nil {
+			return nil, err
+		}
+		return nil, syscall.EINVAL
+	}
+	return &info, nil
+}