windows: add window handle related system calls

https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-enumwindows
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-enumchildwindows
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getclassnamew
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getdesktopwindow
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getforegroundwindow
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-iswindow
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-iswindowunicode
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-iswindowvisible
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getguithreadinfo

Change-Id: I21fbf47e1f459e86503e0e876b44cf47c98b2aa0
GitHub-Last-Rev: 242b79ffb8cbfe7b3359e35379fa3227a70fc0f1
GitHub-Pull-Request: golang/sys#122
Reviewed-on: https://go-review.googlesource.com/c/sys/+/399134
Auto-Submit: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

windows/syscall_windows.go

@@ -364,6 +364,15 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
 //sys	GetActiveProcessorCount(groupNumber uint16) (ret uint32)
 //sys	GetMaximumProcessorCount(groupNumber uint16) (ret uint32)
+//sys	EnumWindows(enumFunc uintptr, param unsafe.Pointer) (err error) = user32.EnumWindows
+//sys	EnumChildWindows(hwnd HWND, enumFunc uintptr, param unsafe.Pointer) = user32.EnumChildWindows
+//sys	GetClassName(hwnd HWND, className *uint16, maxCount int32) (copied int32, err error) = user32.GetClassNameW
+//sys	GetDesktopWindow() (hwnd HWND) = user32.GetDesktopWindow
+//sys	GetForegroundWindow() (hwnd HWND) = user32.GetForegroundWindow
+//sys	IsWindow(hwnd HWND) (isWindow bool) = user32.IsWindow
+//sys	IsWindowUnicode(hwnd HWND) (isUnicode bool) = user32.IsWindowUnicode
+//sys	IsWindowVisible(hwnd HWND) (isVisible bool) = user32.IsWindowVisible
+//sys	GetGUIThreadInfo(thread uint32, info *GUIThreadInfo) (err error) = user32.GetGUIThreadInfo
 
 // Volume Management Functions
 //sys	DefineDosDevice(flags uint32, deviceName *uint16, targetPath *uint16) (err error) = DefineDosDeviceW

windows/types_windows.go

@@ -3213,3 +3213,22 @@ type ModuleInfo struct {
 }
 
 const ALL_PROCESSOR_GROUPS = 0xFFFF
+
+type Rect struct {
+	Left   int32
+	Top    int32
+	Right  int32
+	Bottom int32
+}
+
+type GUIThreadInfo struct {
+	Size        uint32
+	Flags       uint32
+	Active      HWND
+	Focus       HWND
+	Capture     HWND
+	MenuOwner   HWND
+	MoveSize    HWND
+	CaretHandle HWND
+	CaretRect   Rect
+}

windows/zsyscall_windows.go

@@ -444,9 +444,18 @@ var (
 	procCommandLineToArgvW                                   = modshell32.NewProc("CommandLineToArgvW")
 	procSHGetKnownFolderPath                                 = modshell32.NewProc("SHGetKnownFolderPath")
 	procShellExecuteW                                        = modshell32.NewProc("ShellExecuteW")
+	procEnumChildWindows                                     = moduser32.NewProc("EnumChildWindows")
+	procEnumWindows                                          = moduser32.NewProc("EnumWindows")
 	procExitWindowsEx                                        = moduser32.NewProc("ExitWindowsEx")
+	procGetClassNameW                                        = moduser32.NewProc("GetClassNameW")
+	procGetDesktopWindow                                     = moduser32.NewProc("GetDesktopWindow")
+	procGetForegroundWindow                                  = moduser32.NewProc("GetForegroundWindow")
+	procGetGUIThreadInfo                                     = moduser32.NewProc("GetGUIThreadInfo")
 	procGetShellWindow                                       = moduser32.NewProc("GetShellWindow")
 	procGetWindowThreadProcessId                             = moduser32.NewProc("GetWindowThreadProcessId")
+	procIsWindow                                             = moduser32.NewProc("IsWindow")
+	procIsWindowUnicode                                      = moduser32.NewProc("IsWindowUnicode")
+	procIsWindowVisible                                      = moduser32.NewProc("IsWindowVisible")
 	procMessageBoxW                                          = moduser32.NewProc("MessageBoxW")
 	procCreateEnvironmentBlock                               = moduserenv.NewProc("CreateEnvironmentBlock")
 	procDestroyEnvironmentBlock                              = moduserenv.NewProc("DestroyEnvironmentBlock")
@@ -3802,6 +3811,19 @@ func ShellExecute(hwnd Handle, verb *uint16, file *uint16, args *uint16, cwd *ui
 	return
 }
 
+func EnumChildWindows(hwnd HWND, enumFunc uintptr, param unsafe.Pointer) {
+	syscall.Syscall(procEnumChildWindows.Addr(), 3, uintptr(hwnd), uintptr(enumFunc), uintptr(param))
+	return
+}
+
+func EnumWindows(enumFunc uintptr, param unsafe.Pointer) (err error) {
+	r1, _, e1 := syscall.Syscall(procEnumWindows.Addr(), 2, uintptr(enumFunc), uintptr(param), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func ExitWindowsEx(flags uint32, reason uint32) (err error) {
 	r1, _, e1 := syscall.Syscall(procExitWindowsEx.Addr(), 2, uintptr(flags), uintptr(reason), 0)
 	if r1 == 0 {
@@ -3810,6 +3832,35 @@ func ExitWindowsEx(flags uint32, reason uint32) (err error) {
 	return
 }
 
+func GetClassName(hwnd HWND, className *uint16, maxCount int32) (copied int32, err error) {
+	r0, _, e1 := syscall.Syscall(procGetClassNameW.Addr(), 3, uintptr(hwnd), uintptr(unsafe.Pointer(className)), uintptr(maxCount))
+	copied = int32(r0)
+	if copied == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func GetDesktopWindow() (hwnd HWND) {
+	r0, _, _ := syscall.Syscall(procGetDesktopWindow.Addr(), 0, 0, 0, 0)
+	hwnd = HWND(r0)
+	return
+}
+
+func GetForegroundWindow() (hwnd HWND) {
+	r0, _, _ := syscall.Syscall(procGetForegroundWindow.Addr(), 0, 0, 0, 0)
+	hwnd = HWND(r0)
+	return
+}
+
+func GetGUIThreadInfo(thread uint32, info *GUIThreadInfo) (err error) {
+	r1, _, e1 := syscall.Syscall(procGetGUIThreadInfo.Addr(), 2, uintptr(thread), uintptr(unsafe.Pointer(info)), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func GetShellWindow() (shellWindow HWND) {
 	r0, _, _ := syscall.Syscall(procGetShellWindow.Addr(), 0, 0, 0, 0)
 	shellWindow = HWND(r0)
@@ -3825,6 +3876,24 @@ func GetWindowThreadProcessId(hwnd HWND, pid *uint32) (tid uint32, err error) {
 	return
 }
 
+func IsWindow(hwnd HWND) (isWindow bool) {
+	r0, _, _ := syscall.Syscall(procIsWindow.Addr(), 1, uintptr(hwnd), 0, 0)
+	isWindow = r0 != 0
+	return
+}
+
+func IsWindowUnicode(hwnd HWND) (isUnicode bool) {
+	r0, _, _ := syscall.Syscall(procIsWindowUnicode.Addr(), 1, uintptr(hwnd), 0, 0)
+	isUnicode = r0 != 0
+	return
+}
+
+func IsWindowVisible(hwnd HWND) (isVisible bool) {
+	r0, _, _ := syscall.Syscall(procIsWindowVisible.Addr(), 1, uintptr(hwnd), 0, 0)
+	isVisible = r0 != 0
+	return
+}
+
 func MessageBox(hwnd HWND, text *uint16, caption *uint16, boxtype uint32) (ret int32, err error) {
 	r0, _, e1 := syscall.Syscall6(procMessageBoxW.Addr(), 4, uintptr(hwnd), uintptr(unsafe.Pointer(text)), uintptr(unsafe.Pointer(caption)), uintptr(boxtype), 0, 0)
 	ret = int32(r0)