readline windows terminal support (#950)

- update the readline package to have basic support on windows, this is not full feature parity with the unix cli yet

readline/buffer.go

@@ -2,6 +2,7 @@ package readline
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/emirpasic/gods/lists/arraylist"
 	"golang.org/x/term"
@@ -17,7 +18,8 @@ type Buffer struct {
 }
 
 func NewBuffer(prompt *Prompt) (*Buffer, error) {
-	width, height, err := term.GetSize(0)
+	fd := int(os.Stdout.Fd())
+	width, height, err := term.GetSize(fd)
 	if err != nil {
 		fmt.Println("Error getting size:", err)
 		return nil, err

readline/readline.go

@@ -51,11 +51,12 @@ func (i *Instance) Readline() (string, error) {
 	}
 	fmt.Print(prompt)
 
-	termios, err := SetRawMode(syscall.Stdin)
+	fd := int(syscall.Stdin)
+	termios, err := SetRawMode(fd)
 	if err != nil {
 		return "", err
 	}
-	defer UnsetRawMode(syscall.Stdin, termios)
+	defer UnsetRawMode(fd, termios)
 
 	buf, _ := NewBuffer(i.Prompt)
 

readline/term_windows.go

@@ -0,0 +1,62 @@
+package readline
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	enableLineInput       = 2
+	enableWindowInput     = 8
+	enableMouseInput      = 16
+	enableInsertMode      = 32
+	enableQuickEditMode   = 64
+	enableExtendedFlags   = 128
+	enableProcessedOutput = 1
+	enableWrapAtEolOutput = 2
+	enableAutoPosition    = 256 // Cursor position is not affected by writing data to the console.
+	enableEchoInput       = 4   // Characters are written to the console as they're read.
+	enableProcessedInput  = 1   // Enables input processing (like recognizing Ctrl+C).
+)
+
+var kernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+var (
+	procGetConsoleMode = kernel32.NewProc("GetConsoleMode")
+	procSetConsoleMode = kernel32.NewProc("SetConsoleMode")
+)
+
+type State struct {
+	mode uint32
+}
+
+// IsTerminal checks if the given file descriptor is associated with a terminal
+func IsTerminal(fd int) bool {
+	var st uint32
+	r, _, e := syscall.SyscallN(procGetConsoleMode.Addr(), uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
+	// if the call succeeds and doesn't produce an error, it's a terminal
+	return r != 0 && e == 0
+}
+
+func SetRawMode(fd int) (*State, error) {
+	var st uint32
+	// retrieve the current mode of the terminal
+	_, _, e := syscall.SyscallN(procGetConsoleMode.Addr(), uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+	// modify the mode to set it to raw
+	raw := st &^ (enableEchoInput | enableProcessedInput | enableLineInput | enableProcessedOutput)
+	// apply the new mode to the terminal
+	_, _, e = syscall.SyscallN(procSetConsoleMode.Addr(), uintptr(fd), uintptr(raw), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+	// return the original state so that it can be restored later
+	return &State{st}, nil
+}
+
+func UnsetRawMode(fd int, state *State) error {
+	_, _, err := syscall.SyscallN(procSetConsoleMode.Addr(), uintptr(fd), uintptr(state.mode), 0)
+	return err
+}