windows: add console input handling api

Add Console API input handling syscalls. This is an effort to upstream
the amazing coninput library by @erikgeiser
https://github.com/erikgeiser/coninput

windows/syscall_windows.go

@@ -310,6 +310,10 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	WriteConsole(console Handle, buf *uint16, towrite uint32, written *uint32, reserved *byte) (err error) = kernel32.WriteConsoleW
 //sys	ReadConsole(console Handle, buf *uint16, toread uint32, read *uint32, inputControl *byte) (err error) = kernel32.ReadConsoleW
 //sys	resizePseudoConsole(pconsole Handle, size uint32) (hr error) = kernel32.ResizePseudoConsole
+//sys	readConsoleInputW(console Handle, buf *InputRecord, toread uint32, read *uint32) (err error) = kernel32.ReadConsoleInputW
+//sys	peekConsoleInputW(console Handle, buf *InputRecord, toread uint32, read *uint32) (err error) = kernel32.PeekConsoleInputW
+//sys	getNumberOfConsoleInputEvents(console Handle, numevents *uint32) (err error) = kernel32.GetNumberOfConsoleInputEvents
+//sys	FlushConsoleInputBuffer(console Handle) (err error) = kernel32.FlushConsoleInputBuffer
 //sys	CreateToolhelp32Snapshot(flags uint32, processId uint32) (handle Handle, err error) [failretval==InvalidHandle] = kernel32.CreateToolhelp32Snapshot
 //sys	Module32First(snapshot Handle, moduleEntry *ModuleEntry32) (err error) = kernel32.Module32FirstW
 //sys	Module32Next(snapshot Handle, moduleEntry *ModuleEntry32) (err error) = kernel32.Module32NextW
@@ -1916,3 +1920,44 @@ const (
 	EV_ERR     = 0x0080
 	EV_RING    = 0x0100
 )
+
+// ReadConsoleInputW provides an ideomatic interface to the Windows console API
+// function ReadConsoleInputW (see
+// https://docs.microsoft.com/en-us/windows/console/readconsoleinput). The size
+// of inputRecords must be greater than zero.
+func ReadConsoleInputW(console Handle, inputRecords []InputRecord) (uint32, error) {
+	if len(inputRecords) == 0 {
+		return 0, fmt.Errorf("size of input record buffer cannot be zero")
+	}
+
+	var read uint32
+	err := readConsoleInputW(console, &inputRecords[0], uint32(len(inputRecords)), &read)
+
+	return read, err
+}
+
+// PeekConsoleInputW provides an ideomatic interface to the Windows console API
+// function PeekConsoleInputW (see
+// https://docs.microsoft.com/en-us/windows/console/peekconsoleinput). The size
+// of inputRecords must be greater than zero.
+func PeekConsoleInputW(console Handle, inputRecords []InputRecord) (uint32, error) {
+	if len(inputRecords) == 0 {
+		return 0, fmt.Errorf("size of input record buffer cannot be zero")
+	}
+
+	var read uint32
+
+	err := peekConsoleInputW(console, &inputRecords[0], uint32(len(inputRecords)), &read)
+
+	return read, err
+}
+
+// GetNumberOfConsoleInputEvents provides an ideomatic interface to the Windows
+// console API function GetNumberOfConsoleInputEvents (see
+// https://docs.microsoft.com/en-us/windows/console/getnumberofconsoleinputevents).
+func GetNumberOfConsoleInputEvents(console Handle) (uint32, error) {
+	var nEvents uint32
+	err := getNumberOfConsoleInputEvents(console, &nEvents)
+
+	return nEvents, err
+}