Make height option work under Windows (#1341)

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

5 files changed, 244 insertions, 69 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b1f68751..1a16fd53 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ CHANGELOG
       finder instead of printing horizontal lines above and below it.
       The previous style is available via `--border=horizontal`
 - Added `--pointer` and `--marker` options
+- `--height` option is now available on Windows binary (@kelleyma49)
 - More keys and actions for `--bind`
 - Bug fixes and improvements
 - Vim plugin: Floating windows support
diff --git a/src/options.go b/src/options.go
index b87e85c2..0fd97050 100644
--- a/src/options.go
+++ b/src/options.go
@@ -11,7 +11,6 @@ import (
 
 	"github.com/junegunn/fzf/src/algo"
 	"github.com/junegunn/fzf/src/tui"
-	"github.com/junegunn/fzf/src/util"
 
 	"github.com/mattn/go-runewidth"
 	"github.com/mattn/go-shellwords"
@@ -1412,8 +1411,8 @@ func validateSign(sign string, signOptName string) error {
 }
 
 func postProcessOptions(opts *Options) {
-	if util.IsWindows() && opts.Height.size > 0 {
-		errorExit("--height option is currently not supported on Windows")
+	if !tui.IsLightRendererSupported() && opts.Height.size > 0 {
+		errorExit("--height option is currently not supported on this platform")
 	}
 	// Default actions for CTRL-N / CTRL-P when --history is set
 	if opts.History != nil {
diff --git a/src/tui/light.go b/src/tui/light.go
index d8de4b66..3ff84870 100644
--- a/src/tui/light.go
+++ b/src/tui/light.go
@@ -7,7 +7,6 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
-	"syscall"
 	"time"
 	"unicode/utf8"
 
@@ -30,21 +29,6 @@ const consoleDevice string = "/dev/tty"
 
 var offsetRegexp *regexp.Regexp = regexp.MustCompile("(.*)\x1b\\[([0-9]+);([0-9]+)R")
 
-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) stderr(str string) {
 	r.stderrInternal(str, true)
 }
@@ -101,6 +85,13 @@ type LightRenderer struct {
 	y             int
 	x             int
 	maxHeightFunc func(int) int
+
+	// Windows only
+	ttyinChannel    chan byte
+	inHandle        uintptr
+	outHandle       uintptr
+	origStateInput  uint32
+	origStateOutput uint32
 }
 
 type LightWindow struct {
@@ -134,10 +125,6 @@ func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop in
 	return &r
 }
 
-func (r *LightRenderer) fd() int {
-	return int(r.ttyin.Fd())
-}
-
 func (r *LightRenderer) defaultTheme() *ColorTheme {
 	if strings.Contains(os.Getenv("TERM"), "256") {
 		return Dark256
@@ -149,22 +136,6 @@ func (r *LightRenderer) defaultTheme() *ColorTheme {
 	return Default16
 }
 
-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 repeat(r rune, times int) string {
 	if times > 0 {
 		return strings.Repeat(string(r), times)
@@ -183,13 +154,9 @@ func atoi(s string, defaultValue int) int {
 func (r *LightRenderer) Init() {
 	r.escDelay = atoi(os.Getenv("ESCDELAY"), defaultEscDelay)
 
-	fd := r.fd()
-	origState, err := terminal.GetState(fd)
-	if err != nil {
+	if err := r.initPlatform(); err != nil {
 		errorExit(err.Error())
 	}
-	r.origState = origState
-	terminal.MakeRaw(fd)
 	r.updateTerminalSize()
 	initTheme(r.theme, r.defaultTheme(), r.forceBlack)
 
@@ -262,28 +229,6 @@ func getEnv(name string, defaultValue int) int {
 	return atoi(env, defaultValue)
 }
 
-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) 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
-}
-
 func (r *LightRenderer) getBytes() []byte {
 	return r.getBytesInternal(r.buffer, false)
 }
@@ -604,7 +549,7 @@ func (r *LightRenderer) rmcup() {
 }
 
 func (r *LightRenderer) Pause(clear bool) {
-	terminal.Restore(r.fd(), r.origState)
+	r.restoreTerminal()
 	if clear {
 		if r.fullscreen {
 			r.rmcup()
@@ -617,7 +562,7 @@ func (r *LightRenderer) Pause(clear bool) {
 }
 
 func (r *LightRenderer) Resume(clear bool) {
-	terminal.MakeRaw(r.fd())
+	r.setupTerminal()
 	if clear {
 		if r.fullscreen {
 			r.smcup()
@@ -671,7 +616,8 @@ func (r *LightRenderer) Close() {
 		r.csi("?1000l")
 	}
 	r.flush()
-	terminal.Restore(r.fd(), r.origState)
+	r.closePlatform()
+	r.restoreTerminal()
 }
 
 func (r *LightRenderer) MaxX() int {
diff --git a/src/tui/light_unix.go b/src/tui/light_unix.go
new file mode 100644
index 00000000..e4ce6313
--- /dev/null
+++ b/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
+}
diff --git a/src/tui/light_windows.go b/src/tui/light_windows.go
new file mode 100644
index 00000000..6f876af2
--- /dev/null
+++ b/src/tui/light_windows.go
@@ -0,0 +1,132 @@
+//+build windows
+
+package tui
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/junegunn/fzf/src/util"
+	"golang.org/x/sys/windows"
+)
+
+var (
+	consoleFlagsInput  = uint32(windows.ENABLE_VIRTUAL_TERMINAL_INPUT | windows.ENABLE_PROCESSED_INPUT | windows.ENABLE_EXTENDED_FLAGS)
+	consoleFlagsOutput = uint32(windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING | windows.ENABLE_PROCESSED_OUTPUT | windows.DISABLE_NEWLINE_AUTO_RETURN)
+)
+
+// IsLightRendererSupported checks to see if the Light renderer is supported
+func IsLightRendererSupported() bool {
+	var oldState uint32
+	// enable vt100 emulation (https://docs.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences)
+	if windows.GetConsoleMode(windows.Stderr, &oldState) != nil {
+		return false
+	}
+	// attempt to set mode to determine if we support VT 100 codes. This will work on newer Windows 10
+	// version:
+	canSetVt100 := windows.SetConsoleMode(windows.Stderr, oldState|windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING) == nil
+	var checkState uint32
+	if windows.GetConsoleMode(windows.Stderr, &checkState) != nil ||
+		(checkState&windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING) != windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING {
+		return false
+	}
+	windows.SetConsoleMode(windows.Stderr, oldState)
+	return canSetVt100
+}
+
+func (r *LightRenderer) initPlatform() error {
+	//outHandle := windows.Stdout
+	outHandle, _ := syscall.Open("CONOUT$", syscall.O_RDWR, 0)
+	// enable vt100 emulation (https://docs.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences)
+	if err := windows.GetConsoleMode(windows.Handle(outHandle), &r.origStateOutput); err != nil {
+		return err
+	}
+	r.outHandle = uintptr(outHandle)
+	inHandle, _ := syscall.Open("CONIN$", syscall.O_RDWR, 0)
+	if err := windows.GetConsoleMode(windows.Handle(inHandle), &r.origStateInput); err != nil {
+		return err
+	}
+	r.inHandle = uintptr(inHandle)
+
+	r.setupTerminal()
+
+	// channel for non-blocking reads. Buffer to make sure
+	// we get the ESC sets:
+	r.ttyinChannel = make(chan byte, 12)
+
+	// the following allows for non-blocking IO.
+	// syscall.SetNonblock() is a NOOP under Windows.
+	go func() {
+		fd := int(r.inHandle)
+		b := make([]byte, 1)
+		for {
+			// HACK: if run from PSReadline, something resets ConsoleMode to remove ENABLE_VIRTUAL_TERMINAL_INPUT.
+			_ = windows.SetConsoleMode(windows.Handle(r.inHandle), consoleFlagsInput)
+
+			_, err := util.Read(fd, b)
+			if err == nil {
+				r.ttyinChannel <- b[0]
+			}
+		}
+	}()
+
+	return nil
+}
+
+func (r *LightRenderer) closePlatform() {
+	windows.SetConsoleMode(windows.Handle(r.outHandle), r.origStateOutput)
+	windows.SetConsoleMode(windows.Handle(r.inHandle), r.origStateInput)
+}
+
+func openTtyIn() *os.File {
+	// not used
+	return nil
+}
+
+func (r *LightRenderer) setupTerminal() error {
+	if err := windows.SetConsoleMode(windows.Handle(r.outHandle), consoleFlagsOutput); err != nil {
+		return err
+	}
+	return windows.SetConsoleMode(windows.Handle(r.inHandle), consoleFlagsInput)
+}
+
+func (r *LightRenderer) restoreTerminal() error {
+	if err := windows.SetConsoleMode(windows.Handle(r.inHandle), r.origStateInput); err != nil {
+		return err
+	}
+	return windows.SetConsoleMode(windows.Handle(r.outHandle), r.origStateOutput)
+}
+
+func (r *LightRenderer) updateTerminalSize() {
+	var bufferInfo windows.ConsoleScreenBufferInfo
+	if err := windows.GetConsoleScreenBufferInfo(windows.Handle(r.outHandle), &bufferInfo); err != nil {
+		r.width = getEnv("COLUMNS", defaultWidth)
+		r.height = r.maxHeightFunc(getEnv("LINES", defaultHeight))
+
+	} else {
+		r.width = int(bufferInfo.Window.Right - bufferInfo.Window.Left)
+		r.height = r.maxHeightFunc(int(bufferInfo.Window.Bottom - bufferInfo.Window.Top))
+	}
+}
+
+func (r *LightRenderer) findOffset() (row int, col int) {
+	var bufferInfo windows.ConsoleScreenBufferInfo
+	if err := windows.GetConsoleScreenBufferInfo(windows.Handle(r.outHandle), &bufferInfo); err != nil {
+		return -1, -1
+	}
+	return int(bufferInfo.CursorPosition.X), int(bufferInfo.CursorPosition.Y)
+}
+
+func (r *LightRenderer) getch(nonblock bool) (int, bool) {
+	if nonblock {
+		select {
+		case bc := <-r.ttyinChannel:
+			return int(bc), true
+		default:
+			return 0, false
+		}
+	} else {
+		bc := <-r.ttyinChannel
+		return int(bc), true
+	}
+}