Make height option work under Windows (#1341)

Separate Unix & Windows code into platform specific files for light renderer

src/tui/light_unix.go

@@ -0,0 +1,97 @@
+// +build !windows
+
+package tui
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+
+	"github.com/junegunn/fzf/src/util"
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+func IsLightRendererSupported() bool {
+	return true
+}
+
+func (r *LightRenderer) fd() int {
+	return int(r.ttyin.Fd())
+}
+
+func (r *LightRenderer) initPlatform() error {
+	fd := r.fd()
+	origState, err := terminal.GetState(fd)
+	if err != nil {
+		return err
+	}
+	r.origState = origState
+	terminal.MakeRaw(fd)
+	return nil
+}
+
+func (r *LightRenderer) closePlatform() {
+	// NOOP
+}
+
+func openTtyIn() *os.File {
+	in, err := os.OpenFile(consoleDevice, syscall.O_RDONLY, 0)
+	if err != nil {
+		tty := ttyname()
+		if len(tty) > 0 {
+			if in, err := os.OpenFile(tty, syscall.O_RDONLY, 0); err == nil {
+				return in
+			}
+		}
+		fmt.Fprintln(os.Stderr, "Failed to open "+consoleDevice)
+		os.Exit(2)
+	}
+	return in
+}
+
+func (r *LightRenderer) setupTerminal() {
+	terminal.MakeRaw(r.fd())
+}
+
+func (r *LightRenderer) restoreTerminal() {
+	terminal.Restore(r.fd(), r.origState)
+}
+
+func (r *LightRenderer) updateTerminalSize() {
+	width, height, err := terminal.GetSize(r.fd())
+
+	if err == nil {
+		r.width = width
+		r.height = r.maxHeightFunc(height)
+	} else {
+		r.width = getEnv("COLUMNS", defaultWidth)
+		r.height = r.maxHeightFunc(getEnv("LINES", defaultHeight))
+	}
+}
+
+func (r *LightRenderer) findOffset() (row int, col int) {
+	r.csi("6n")
+	r.flush()
+	bytes := []byte{}
+	for tries := 0; tries < offsetPollTries; tries++ {
+		bytes = r.getBytesInternal(bytes, tries > 0)
+		offsets := offsetRegexp.FindSubmatch(bytes)
+		if len(offsets) > 3 {
+			// Add anything we skipped over to the input buffer
+			r.buffer = append(r.buffer, offsets[1]...)
+			return atoi(string(offsets[2]), 0) - 1, atoi(string(offsets[3]), 0) - 1
+		}
+	}
+	return -1, -1
+}
+
+func (r *LightRenderer) getch(nonblock bool) (int, bool) {
+	b := make([]byte, 1)
+	fd := r.fd()
+	util.SetNonblock(r.ttyin, nonblock)
+	_, err := util.Read(fd, b)
+	if err != nil {
+		return 0, false
+	}
+	return int(b[0]), true
+}