windows: add Get*PreferredUILanguages

This commit adds the following MUI functions:
- GetUserPreferredUILanguages
- GetSystemPreferredUILanguages
- GetThreadPreferredUILanguages
- GetProcessPreferredUILanguages

Change-Id: I44f1c07245ab814935778c6b910b224d24cc753c
Reviewed-on: https://go-review.googlesource.com/c/sys/+/207860
Reviewed-by: Simon Rozman <simon@rozman.si>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

windows/syscall_windows.go

@@ -313,6 +313,10 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	CoTaskMemFree(address unsafe.Pointer) = ole32.CoTaskMemFree
 //sys	rtlGetVersion(info *OsVersionInfoEx) (ret error) = ntdll.RtlGetVersion
 //sys	rtlGetNtVersionNumbers(majorVersion *uint32, minorVersion *uint32, buildNumber *uint32) = ntdll.RtlGetNtVersionNumbers
+//sys	getProcessPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) = kernel32.GetProcessPreferredUILanguages
+//sys	getThreadPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) = kernel32.GetThreadPreferredUILanguages
+//sys	getUserPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) = kernel32.GetUserPreferredUILanguages
+//sys	getSystemPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) = kernel32.GetSystemPreferredUILanguages
 
 // Process Status API (PSAPI)
 //sys	EnumProcesses(processIds []uint32, bytesReturned *uint32) (err error) = psapi.EnumProcesses
@@ -1378,3 +1382,54 @@ func RtlGetNtVersionNumbers() (majorVersion, minorVersion, buildNumber uint32) {
 	buildNumber &= 0xffff
 	return
 }
+
+// GetProcessPreferredUILanguages retrieves the process preferred UI languages.
+func GetProcessPreferredUILanguages(flags uint32) ([]string, error) {
+	return getUILanguages(flags, getProcessPreferredUILanguages)
+}
+
+// GetThreadPreferredUILanguages retrieves the thread preferred UI languages for the current thread.
+func GetThreadPreferredUILanguages(flags uint32) ([]string, error) {
+	return getUILanguages(flags, getThreadPreferredUILanguages)
+}
+
+// GetUserPreferredUILanguages retrieves information about the user preferred UI languages.
+func GetUserPreferredUILanguages(flags uint32) ([]string, error) {
+	return getUILanguages(flags, getUserPreferredUILanguages)
+}
+
+// GetSystemPreferredUILanguages retrieves the system preferred UI languages.
+func GetSystemPreferredUILanguages(flags uint32) ([]string, error) {
+	return getUILanguages(flags, getSystemPreferredUILanguages)
+}
+
+func getUILanguages(flags uint32, f func(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) error) ([]string, error) {
+	size := uint32(128)
+	for {
+		var numLanguages uint32
+		buf := make([]uint16, size)
+		err := f(flags, &numLanguages, &buf[0], &size)
+		if err == ERROR_INSUFFICIENT_BUFFER {
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+		buf = buf[:size]
+		if numLanguages == 0 || len(buf) == 0 { // GetProcessPreferredUILanguages may return numLanguages==0 with "\0\0"
+			return []string{}, nil
+		}
+		if buf[len(buf)-1] == 0 {
+			buf = buf[:len(buf)-1] // remove terminating null
+		}
+		languages := make([]string, 0, numLanguages)
+		from := 0
+		for i, c := range buf {
+			if c == 0 {
+				languages = append(languages, string(utf16.Decode(buf[from:i])))
+				from = i + 1
+			}
+		}
+		return languages, nil
+	}
+}

windows/syscall_windows_test.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"strings"
 	"syscall"
 	"testing"
@@ -377,3 +378,29 @@ func TestGetDiskFreeSpaceEx(t *testing.T) {
 		t.Errorf("totalNumberOfFreeBytes: got 0; want > 0")
 	}
 }
+
+func TestGetPreferredUILanguages(t *testing.T) {
+	tab := map[string]func(flags uint32) ([]string, error){
+		"GetProcessPreferredUILanguages": windows.GetProcessPreferredUILanguages,
+		"GetThreadPreferredUILanguages":  windows.GetThreadPreferredUILanguages,
+		"GetUserPreferredUILanguages":    windows.GetUserPreferredUILanguages,
+		"GetSystemPreferredUILanguages":  windows.GetSystemPreferredUILanguages,
+	}
+	for fName, f := range tab {
+		lang, err := f(windows.MUI_LANGUAGE_ID)
+		if err != nil {
+			t.Errorf(`failed to call %v(MUI_LANGUAGE_ID): %v`, fName, err)
+		}
+		for _, l := range lang {
+			_, err := strconv.ParseUint(l, 16, 16)
+			if err != nil {
+				t.Errorf(`%v(MUI_LANGUAGE_ID) returned unexpected LANGID: %v`, fName, l)
+			}
+		}
+
+		lang, err = f(windows.MUI_LANGUAGE_NAME)
+		if err != nil {
+			t.Errorf(`failed to call %v(MUI_LANGUAGE_NAME): %v`, fName, err)
+		}
+	}
+}

windows/types_windows.go

@@ -1742,3 +1742,36 @@ const (
 	GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT = 2
 	GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS       = 4
 )
+
+// MUI function flag values
+const (
+	MUI_LANGUAGE_ID                    = 0x4
+	MUI_LANGUAGE_NAME                  = 0x8
+	MUI_MERGE_SYSTEM_FALLBACK          = 0x10
+	MUI_MERGE_USER_FALLBACK            = 0x20
+	MUI_UI_FALLBACK                    = MUI_MERGE_SYSTEM_FALLBACK | MUI_MERGE_USER_FALLBACK
+	MUI_THREAD_LANGUAGES               = 0x40
+	MUI_CONSOLE_FILTER                 = 0x100
+	MUI_COMPLEX_SCRIPT_FILTER          = 0x200
+	MUI_RESET_FILTERS                  = 0x001
+	MUI_USER_PREFERRED_UI_LANGUAGES    = 0x10
+	MUI_USE_INSTALLED_LANGUAGES        = 0x20
+	MUI_USE_SEARCH_ALL_LANGUAGES       = 0x40
+	MUI_LANG_NEUTRAL_PE_FILE           = 0x100
+	MUI_NON_LANG_NEUTRAL_FILE          = 0x200
+	MUI_MACHINE_LANGUAGE_SETTINGS      = 0x400
+	MUI_FILETYPE_NOT_LANGUAGE_NEUTRAL  = 0x001
+	MUI_FILETYPE_LANGUAGE_NEUTRAL_MAIN = 0x002
+	MUI_FILETYPE_LANGUAGE_NEUTRAL_MUI  = 0x004
+	MUI_QUERY_TYPE                     = 0x001
+	MUI_QUERY_CHECKSUM                 = 0x002
+	MUI_QUERY_LANGUAGE_NAME            = 0x004
+	MUI_QUERY_RESOURCE_TYPES           = 0x008
+	MUI_FILEINFO_VERSION               = 0x001
+
+	MUI_FULL_LANGUAGE      = 0x01
+	MUI_PARTIAL_LANGUAGE   = 0x02
+	MUI_LIP_LANGUAGE       = 0x04
+	MUI_LANGUAGE_INSTALLED = 0x20
+	MUI_LANGUAGE_LICENSED  = 0x40
+)

windows/zsyscall_windows.go

@@ -248,6 +248,10 @@ var (
 	procCoTaskMemFree                                        = modole32.NewProc("CoTaskMemFree")
 	procRtlGetVersion                                        = modntdll.NewProc("RtlGetVersion")
 	procRtlGetNtVersionNumbers                               = modntdll.NewProc("RtlGetNtVersionNumbers")
+	procGetProcessPreferredUILanguages                       = modkernel32.NewProc("GetProcessPreferredUILanguages")
+	procGetThreadPreferredUILanguages                        = modkernel32.NewProc("GetThreadPreferredUILanguages")
+	procGetUserPreferredUILanguages                          = modkernel32.NewProc("GetUserPreferredUILanguages")
+	procGetSystemPreferredUILanguages                        = modkernel32.NewProc("GetSystemPreferredUILanguages")
 	procEnumProcesses                                        = modpsapi.NewProc("EnumProcesses")
 	procWSAStartup                                           = modws2_32.NewProc("WSAStartup")
 	procWSACleanup                                           = modws2_32.NewProc("WSACleanup")
@@ -2760,6 +2764,54 @@ func rtlGetNtVersionNumbers(majorVersion *uint32, minorVersion *uint32, buildNum
 	return
 }
 
+func getProcessPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procGetProcessPreferredUILanguages.Addr(), 4, uintptr(flags), uintptr(unsafe.Pointer(numLanguages)), uintptr(unsafe.Pointer(buf)), uintptr(unsafe.Pointer(bufSize)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func getThreadPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procGetThreadPreferredUILanguages.Addr(), 4, uintptr(flags), uintptr(unsafe.Pointer(numLanguages)), uintptr(unsafe.Pointer(buf)), uintptr(unsafe.Pointer(bufSize)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func getUserPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procGetUserPreferredUILanguages.Addr(), 4, uintptr(flags), uintptr(unsafe.Pointer(numLanguages)), uintptr(unsafe.Pointer(buf)), uintptr(unsafe.Pointer(bufSize)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func getSystemPreferredUILanguages(flags uint32, numLanguages *uint32, buf *uint16, bufSize *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procGetSystemPreferredUILanguages.Addr(), 4, uintptr(flags), uintptr(unsafe.Pointer(numLanguages)), uintptr(unsafe.Pointer(buf)), uintptr(unsafe.Pointer(bufSize)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func EnumProcesses(processIds []uint32, bytesReturned *uint32) (err error) {
 	var _p0 *uint32
 	if len(processIds) > 0 {