// +build windows
package winterm
import (
"fmt"
"syscall"
"unsafe"
)
//===========================================================================================================
// IMPORTANT NOTE:
//
// The methods below make extensive use of the "unsafe" package to obtain the required pointers.
// Beginning in Go 1.3, the garbage collector may release local variables (e.g., incoming arguments, stack
// variables) the pointers reference *before* the API completes.
//
// As a result, in those cases, the code must hint that the variables remain in active by invoking the
// dummy method "use" (see below). Newer versions of Go are planned to change the mechanism to no longer
// require unsafe pointers.
//
// If you add or modify methods, ENSURE protection of local variables through the "use" builtin to inform
// the garbage collector the variables remain in use if:
//
// -- The value is not a pointer (e.g., int32, struct)
// -- The value is not referenced by the method after passing the pointer to Windows
//
// See http://golang.org/doc/go1.3.
//===========================================================================================================
var (
kernel32DLL = syscall.NewLazyDLL("kernel32.dll")
getConsoleCursorInfoProc = kernel32DLL.NewProc("GetConsoleCursorInfo")
setConsoleCursorInfoProc = kernel32DLL.NewProc("SetConsoleCursorInfo")
setConsoleCursorPositionProc = kernel32DLL.NewProc("SetConsoleCursorPosition")
setConsoleModeProc = kernel32DLL.NewProc("SetConsoleMode")
getConsoleScreenBufferInfoProc = kernel32DLL.NewProc("GetConsoleScreenBufferInfo")
setConsoleScreenBufferSizeProc = kernel32DLL.NewProc("SetConsoleScreenBufferSize")
scrollConsoleScreenBufferProc = kernel32DLL.NewProc("ScrollConsoleScreenBufferA")
setConsoleTextAttributeProc = kernel32DLL.NewProc("SetConsoleTextAttribute")
setConsoleWindowInfoProc = kernel32DLL.NewProc("SetConsoleWindowInfo")
writeConsoleOutputProc = kernel32DLL.NewProc("WriteConsoleOutputW")
readConsoleInputProc = kernel32DLL.NewProc("ReadConsoleInputW")
waitForSingleObjectProc = kernel32DLL.NewProc("WaitForSingleObject")
)
// Windows Console constants
const (
// Console modes
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms686033(v=vs.85).aspx.
ENABLE_PROCESSED_INPUT = 0x0001
ENABLE_LINE_INPUT = 0x0002
ENABLE_ECHO_INPUT = 0x0004
ENABLE_WINDOW_INPUT = 0x0008
ENABLE_MOUSE_INPUT = 0x0010
ENABLE_INSERT_MODE = 0x0020
ENABLE_QUICK_EDIT_MODE = 0x0040
ENABLE_EXTENDED_FLAGS = 0x0080
ENABLE_AUTO_POSITION = 0x0100
ENABLE_VIRTUAL_TERMINAL_INPUT = 0x0200
ENABLE_PROCESSED_OUTPUT = 0x0001
ENABLE_WRAP_AT_EOL_OUTPUT = 0x0002
ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004
DISABLE_NEWLINE_AUTO_RETURN = 0x0008
ENABLE_LVB_GRID_WORLDWIDE = 0x0010
// Character attributes
// Note:
// -- The attributes are combined to produce various colors (e.g., Blue + Green will create Cyan).
// Clearing all foreground or background colors results in black; setting all creates white.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms682088(v=vs.85).aspx#_win32_character_attributes.
FOREGROUND_BLUE uint16 = 0x0001
FOREGROUND_GREEN uint16 = 0x0002
FOREGROUND_RED uint16 = 0x0004
FOREGROUND_INTENSITY uint16 = 0x0008
FOREGROUND_MASK uint16 = 0x000F
BACKGROUND_BLUE uint16 = 0x0010
BACKGROUND_GREEN uint16 = 0x0020
BACKGROUND_RED uint16 = 0x0040
BACKGROUND_INTENSITY uint16 = 0x0080
BACKGROUND_MASK uint16 = 0x00F0
COMMON_LVB_MASK uint16 = 0xFF00
COMMON_LVB_REVERSE_VIDEO uint16 = 0x4000
COMMON_LVB_UNDERSCORE uint16 = 0x8000
// Input event types
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms683499(v=vs.85).aspx.
KEY_EVENT = 0x0001
MOUSE_EVENT = 0x0002
WINDOW_BUFFER_SIZE_EVENT = 0x0004
MENU_EVENT = 0x0008
FOCUS_EVENT = 0x0010
// WaitForSingleObject return codes
WAIT_ABANDONED = 0x00000080
WAIT_FAILED = 0xFFFFFFFF
WAIT_SIGNALED = 0x0000000
WAIT_TIMEOUT = 0x00000102
// WaitForSingleObject wait duration
WAIT_INFINITE = 0xFFFFFFFF
WAIT_ONE_SECOND = 1000
WAIT_HALF_SECOND = 500
WAIT_QUARTER_SECOND = 250
)
// Windows API Console types
// -- See https://msdn.microsoft.com/en-us/library/windows/desktop/ms682101(v=vs.85).aspx for Console specific types (e.g., COORD)
// -- See https://msdn.microsoft.com/en-us/library/aa296569(v=vs.60).aspx for comments on alignment
type (
CHAR_INFO struct {
UnicodeChar uint16
Attributes uint16
}
CONSOLE_CURSOR_INFO struct {
Size uint32
Visible int32
}
CONSOLE_SCREEN_BUFFER_INFO struct {
Size COORD
CursorPosition COORD
Attributes uint16
Window SMALL_RECT
MaximumWindowSize COORD
}
COORD struct {
X int16
Y int16
}
SMALL_RECT struct {
Left int16
Top int16
Right int16
Bottom int16
}
// INPUT_RECORD is a C/C++ union of which KEY_EVENT_RECORD is one case, it is also the largest
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms683499(v=vs.85).aspx.
INPUT_RECORD struct {
EventType uint16
KeyEvent KEY_EVENT_RECORD
}
KEY_EVENT_RECORD struct {
KeyDown int32
RepeatCount uint16
VirtualKeyCode uint16
VirtualScanCode uint16
UnicodeChar uint16
ControlKeyState uint32
}
WINDOW_BUFFER_SIZE struct {
Size COORD
}
)
// boolToBOOL converts a Go bool into a Windows int32.
func boolToBOOL(f bool) int32 {
if f {
return int32(1)
} else {
return int32(0)
}
}
// GetConsoleCursorInfo retrieves information about the size and visiblity of the console cursor.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms683163(v=vs.85).aspx.
func GetConsoleCursorInfo(handle uintptr, cursorInfo *CONSOLE_CURSOR_INFO) error {
r1, r2, err := getConsoleCursorInfoProc.Call(handle, uintptr(unsafe.Pointer(cursorInfo)), 0)
return checkError(r1, r2, err)
}
// SetConsoleCursorInfo sets the size and visiblity of the console cursor.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms686019(v=vs.85).aspx.
func SetConsoleCursorInfo(handle uintptr, cursorInfo *CONSOLE_CURSOR_INFO) error {
r1, r2, err := setConsoleCursorInfoProc.Call(handle, uintptr(unsafe.Pointer(cursorInfo)), 0)
return checkError(r1, r2, err)
}
// SetConsoleCursorPosition location of the console cursor.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms686025(v=vs.85).aspx.
func SetConsoleCursorPosition(handle uintptr, coord COORD) error {
r1, r2, err := setConsoleCursorPositionProc.Call(handle, coordToPointer(coord))
use(coord)
return checkError(r1, r2, err)
}
// GetConsoleMode gets the console mode for given file descriptor
// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms683167(v=vs.85).aspx.
func GetConsoleMode(handle uintptr) (mode uint32, err error) {
err = syscall.GetConsoleMode(syscall.Handle(handle), &mode)
return mode, err
}
// SetConsoleMode sets the console mode for given file descriptor
// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms686033(v=vs.85).aspx.
func SetConsoleMode(handle uintptr, mode uint32) error {
r1, r2, err := setConsoleModeProc.Call(handle, uintptr(mode), 0)
use(mode)
return checkError(r1, r2, err)
}
// GetConsoleScreenBufferInfo retrieves information about the specified console screen buffer.
// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms683171(v=vs.85).aspx.
func GetConsoleScreenBufferInfo(handle uintptr) (*CONSOLE_SCREEN_BUFFER_INFO, error) {
info := CONSOLE_SCREEN_BUFFER_INFO{}
err := checkError(getConsoleScreenBufferInfoProc.Call(handle, uintptr(unsafe.Pointer(&info)), 0))
if err != nil {
return nil, err
}
return &info, nil
}
func ScrollConsoleScreenBuffer(handle uintptr, scrollRect SMALL_RECT, clipRect SMALL_RECT, destOrigin COORD, char CHAR_INFO) error {
r1, r2, err := scrollConsoleScreenBufferProc.Call(handle, uintptr(unsafe.Pointer(&scrollRect)), uintptr(unsafe.Pointer(&clipRect)), coordToPointer(destOrigin), uintptr(unsafe.Pointer(&char)))
use(scrollRect)
use(clipRect)
use(destOrigin)
use(char)
return checkError(r1, r2, err)
}
// SetConsoleScreenBufferSize sets the size of the console screen buffer.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms686044(v=vs.85).aspx.
func SetConsoleScreenBufferSize(handle uintptr, coord COORD) error {
r1, r2, err := setConsoleScreenBufferSizeProc.Call(handle, coordToPointer(coord))
use(coord)
return checkError(r1, r2, err)
}
// SetConsoleTextAttribute sets the attributes of characters written to the
// console screen buffer by the WriteFile or WriteConsole function.
// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms686047(v=vs.85).aspx.
func SetConsoleTextAttribute(handle uintptr, attribute uint16) error {
r1, r2, err := setConsoleTextAttributeProc.Call(handle, uintptr(attribute), 0)
use(attribute)
return checkError(r1, r2, err)
}
// SetConsoleWindowInfo sets the size and position of the console screen buffer's window.
// Note that the size and location must be within and no larger than the backing console screen buffer.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms686125(v=vs.85).aspx.
func SetConsoleWindowInfo(handle uintptr, isAbsolute bool, rect SMALL_RECT) error {
r1, r2, err := setConsoleWindowInfoProc.Call(handle, uintptr(boolToBOOL(isAbsolute)), uintptr(unsafe.Pointer(&rect)))
use(isAbsolute)
use(rect)
return checkError(r1, r2, err)
}
// WriteConsoleOutput writes the CHAR_INFOs from the provided buffer to the active console buffer.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms687404(v=vs.85).aspx.
func WriteConsoleOutput(handle uintptr, buffer []CHAR_INFO, bufferSize COORD, bufferCoord COORD, writeRegion *SMALL_RECT) error {
r1, r2, err := writeConsoleOutputProc.Call(handle, uintptr(unsafe.Pointer(&buffer[0])), coordToPointer(bufferSize), coordToPointer(bufferCoord), uintptr(unsafe.Pointer(writeRegion)))
use(buffer)
use(bufferSize)
use(bufferCoord)
return checkError(r1, r2, err)
}
// ReadConsoleInput reads (and removes) data from the console input buffer.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms684961(v=vs.85).aspx.
func ReadConsoleInput(handle uintptr, buffer []INPUT_RECORD, count *uint32) error {
r1, r2, err := readConsoleInputProc.Call(handle, uintptr(unsafe.Pointer(&buffer[0])), uintptr(len(buffer)), uintptr(unsafe.Pointer(count)))
use(buffer)
return checkError(r1, r2, err)
}
// WaitForSingleObject waits for the passed handle to be signaled.
// It returns true if the handle was signaled; false otherwise.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms687032(v=vs.85).aspx.
func WaitForSingleObject(handle uintptr, msWait uint32) (bool, error) {
r1, _, err := waitForSingleObjectProc.Call(handle, uintptr(uint32(msWait)))
switch r1 {
case WAIT_ABANDONED, WAIT_TIMEOUT:
return false, nil
case WAIT_SIGNALED:
return true, nil
}
use(msWait)
return false, err
}
// String helpers
func (info CONSOLE_SCREEN_BUFFER_INFO) String() string {
return fmt.Sprintf("Size(%v) Cursor(%v) Window(%v) Max(%v)", info.Size, info.CursorPosition, info.Window, info.MaximumWindowSize)
}
func (coord COORD) String() string {
return fmt.Sprintf("%v,%v", coord.X, coord.Y)
}
func (rect SMALL_RECT) String() string {
return fmt.Sprintf("(%v,%v),(%v,%v)", rect.Left, rect.Top, rect.Right, rect.Bottom)
}
// checkError evaluates the results of a Windows API call and returns the error if it failed.
func checkError(r1, r2 uintptr, err error) error {
// Windows APIs return non-zero to indicate success
if r1 != 0 {
return nil
}
// Return the error if provided, otherwise default to EINVAL
if err != nil {
return err
}
return syscall.EINVAL
}
// coordToPointer converts a COORD into a uintptr (by fooling the type system).
func coordToPointer(c COORD) uintptr {
// Note: This code assumes the two SHORTs are correctly laid out; the "cast" to uint32 is just to get a pointer to pass.
return uintptr(*((*uint32)(unsafe.Pointer(&c))))
}
// use is a no-op, but the compiler cannot see that it is.
// Calling use(p) ensures that p is kept live until that point.
func use(p interface{}) {}
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