Revert "Revert "term: obtain the cursor position via termios.h (#11372)""

This reverts commit 0376cbf6bd.

vlib/term/declarations_default.c.v

@@ -0,0 +1,10 @@
+module term
+
+pub struct C.termios {
+mut:
+	c_iflag int
+	c_oflag int
+	c_cflag int
+	c_lflag int
+	c_cc    [10]int
+}

vlib/term/declarations_linux.c.v

@@ -0,0 +1,11 @@
+module term
+
+pub struct C.termios {
+mut:
+	c_iflag int
+	c_oflag int
+	c_cflag int
+	c_lflag int
+	c_line  byte
+	c_cc    [10]int
+}

vlib/term/term_nix.c.v

@@ -13,6 +13,10 @@ pub:
 	ws_ypixel u16
 }
 
+fn C.tcgetattr(fd int, ptr &C.termios) int
+
+fn C.tcsetattr(fd int, action int, const_ptr &C.termios)
+
 fn C.ioctl(fd int, request u64, arg voidptr) int
 
 // get_terminal_size returns a number of colums and rows of terminal window.
@@ -21,70 +25,58 @@ pub fn get_terminal_size() (int, int) {
 		return default_columns_size, default_rows_size
 	}
 	w := C.winsize{}
-	C.ioctl(1, u64(C.TIOCGWINSZ), &w)
+	unsafe { C.ioctl(1, u64(C.TIOCGWINSZ), &w) }
 	return int(w.ws_col), int(w.ws_row)
 }
 
 // get_cursor_position returns a Coord containing the current cursor position
-pub fn get_cursor_position() Coord {
+pub fn get_cursor_position() ?Coord {
 	if os.is_atty(1) <= 0 || os.getenv('TERM') == 'dumb' {
-		return Coord{
-			x: 0
-			y: 0
-		}
+		return Coord{0, 0}
 	}
-	// TODO: use termios.h, C.tcgetattr & C.tcsetattr directly,
-	// instead of using `stty`
-	mut oldsettings := os.execute('stty -g')
-	if oldsettings.exit_code < 0 {
-		oldsettings = os.Result{}
+
+	old_state := C.termios{}
+	if unsafe { C.tcgetattr(0, &old_state) } != 0 {
+		return os.last_error()
 	}
-	os.system('stty -echo -icanon time 0')
-	print('\033[6n')
-	mut ch := int(0)
-	mut i := 0
-	// ESC [ YYY `;` XXX `R`
-	mut reading_x := false
-	mut reading_y := false
+	defer {
+		// restore the old terminal state:
+		unsafe { C.tcsetattr(0, C.TCSANOW, &old_state) }
+	}
+
+	mut state := C.termios{}
+	if unsafe { C.tcgetattr(0, &state) } != 0 {
+		return os.last_error()
+	}
+	state.c_lflag &= int(~(u32(C.ICANON) | u32(C.ECHO)))
+	unsafe { C.tcsetattr(0, C.TCSANOW, &state) }
+
+	print('\e[6n')
+
 	mut x := 0
 	mut y := 0
+	mut stage := byte(0)
+
+	// ESC [ YYY `;` XXX `R`
+
 	for {
-		ch = C.getchar()
-		b := byte(ch)
-		i++
-		if i >= 15 {
-			panic('C.getchar() called too many times')
-		}
-		// state management:
-		if b == `R` {
+		w := unsafe { C.getchar() }
+		if w < 0 {
+			return error_with_code('Failed to read from stdin', 888)
+		} else if w == `[` || w == `;` {
+			stage++
+		} else if `0` <= w && w <= `9` {
+			match stage {
+				// converting string values to int:
+				1 { y = y * 10 + int(w - `0`) }
+				2 { x = x * 10 + int(w - `0`) }
+				else {}
+			}
+		} else if w == `R` {
 			break
 		}
-		if b == `[` {
-			reading_y = true
-			reading_x = false
-			continue
-		}
-		if b == `;` {
-			reading_y = false
-			reading_x = true
-			continue
-		}
-		// converting string vals to ints:
-		if reading_x {
-			x *= 10
-			x += (b - byte(`0`))
-		}
-		if reading_y {
-			y *= 10
-			y += (b - byte(`0`))
-		}
-	}
-	// restore the old terminal settings:
-	os.system('stty $oldsettings.output')
-	return Coord{
-		x: x
-		y: y
 	}
+	return Coord{x, y}
 }
 
 // set_terminal_title change the terminal title

vlib/term/term_test.v

@@ -57,9 +57,9 @@ fn test_header() {
 	assert term_width == term.header('1234', '_-/\\/\\').len
 }
 
-fn test_get_cursor_position() {
-	original_position := term.get_cursor_position()
-	cursor_position_1 := term.get_cursor_position()
+fn test_get_cursor_position() ? {
+	original_position := term.get_cursor_position() ?
+	cursor_position_1 := term.get_cursor_position() ?
 	assert original_position.x == cursor_position_1.x
 	assert original_position.y == cursor_position_1.y
 	//
@@ -67,13 +67,13 @@ fn test_get_cursor_position() {
 		x: 10
 		y: 11
 	)
-	cursor_position_2 := term.get_cursor_position()
+	cursor_position_2 := term.get_cursor_position() ?
 	//
 	term.set_cursor_position(
 		x: 5
 		y: 6
 	)
-	cursor_position_3 := term.get_cursor_position()
+	cursor_position_3 := term.get_cursor_position() ?
 	//
 	term.set_cursor_position(original_position)
 	eprintln('original_position: $original_position')

vlib/term/term_windows.c.v

@@ -69,13 +69,15 @@ pub fn get_terminal_size() (int, int) {
 }
 
 // get_cursor_position returns a Coord containing the current cursor position
-pub fn get_cursor_position() Coord {
+pub fn get_cursor_position() ?Coord {
 	mut res := Coord{}
 	if os.is_atty(1) > 0 && os.getenv('TERM') != 'dumb' {
 		info := C.CONSOLE_SCREEN_BUFFER_INFO{}
 		if C.GetConsoleScreenBufferInfo(C.GetStdHandle(C.STD_OUTPUT_HANDLE), &info) {
 			res.x = info.dwCursorPosition.X
 			res.y = info.dwCursorPosition.Y
+		} else {
+			return os.last_error()
 		}
 	}
 	return res

vlib/term/ui/color.v

@@ -4,10 +4,9 @@
 
 module ui
 
-const (
-	value_range = [0x00, 0x5f, 0x87, 0xaf, 0xd7, 0xff]!
-	color_table = init_color_table()
-)
+const value_range = [0x00, 0x5f, 0x87, 0xaf, 0xd7, 0xff]!
+
+pub const color_table = init_color_table()
 
 [direct_array_access]
 fn init_color_table() []int {

vlib/term/ui/declarations_default.c.v

@@ -0,0 +1,10 @@
+module ui
+
+struct C.termios {
+mut:
+	c_iflag int
+	c_oflag int
+	c_cflag int
+	c_lflag int
+	c_cc    [10]int
+}

vlib/term/ui/declarations_linux.c.v

@@ -0,0 +1,11 @@
+module ui
+
+struct C.termios {
+mut:
+	c_iflag int
+	c_oflag int
+	c_cflag int
+	c_lflag int
+	c_line  byte
+	c_cc    [10]int
+}

vlib/term/ui/input_nix.c.v

@@ -8,9 +8,7 @@ mut:
 	read_buf []byte
 }
 
-const (
-	ctx_ptr = &Context(0)
-)
+const ctx_ptr = &Context(0)
 
 pub fn init(cfg Config) &Context {
 	mut ctx := &Context{

vlib/term/ui/input_windows.c.v

@@ -6,11 +6,11 @@ module ui
 import os
 import time
 
-const (
-	buf_size         = 64
-	ctx_ptr          = &Context(0)
-	stdin_at_startup = u32(0)
-)
+const buf_size = 64
+
+const ctx_ptr = &Context(0)
+
+const stdin_at_startup = u32(0)
 
 struct ExtraContext {
 mut:

vlib/term/ui/termios_nix.c.v

@@ -10,27 +10,18 @@ import time
 #include <sys/ioctl.h>
 #include <signal.h>
 
-fn C.tcgetattr(fd int, termios_p &C.termios) int
-
-fn C.tcsetattr(fd int, optional_actions int, termios_p &C.termios) int
-
-fn C.ioctl(fd int, request u64, arg voidptr) int
-
-struct C.termios {
-mut:
-	c_iflag u32
-	c_lflag u32
-	c_cc    [32]byte
-}
-
 struct C.winsize {
 	ws_row u16
 	ws_col u16
 }
 
-const (
-	termios_at_startup = get_termios()
-)
+fn C.tcgetattr(fd int, termios_p &C.termios) int
+
+fn C.tcsetattr(fd int, optional_actions int, const_termios_p &C.termios) int
+
+fn C.ioctl(fd int, request u64, arg voidptr) int
+
+const termios_at_startup = get_termios()
 
 [inline]
 fn get_termios() C.termios {
@@ -74,11 +65,11 @@ fn (mut ctx Context) termios_setup() ? {
 	if ctx.cfg.capture_events {
 		// Set raw input mode by unsetting ICANON and ECHO,
 		// as well as disable e.g. ctrl+c and ctrl.z
-		termios.c_iflag &= ~u32(C.IGNBRK | C.BRKINT | C.PARMRK | C.IXON)
-		termios.c_lflag &= ~u32(C.ICANON | C.ISIG | C.ECHO | C.IEXTEN | C.TOSTOP)
+		termios.c_iflag &= ~(C.IGNBRK | C.BRKINT | C.PARMRK | C.IXON)
+		termios.c_lflag &= ~(C.ICANON | C.ISIG | C.ECHO | C.IEXTEN | C.TOSTOP)
 	} else {
 		// Set raw input mode by unsetting ICANON and ECHO
-		termios.c_lflag &= ~u32(C.ICANON | C.ECHO)
+		termios.c_lflag &= ~(C.ICANON | C.ECHO)
 	}
 
 	if ctx.cfg.hide_cursor {

vlib/term/ui/ui.v

@@ -18,10 +18,9 @@ pub fn (c Color) hex() string {
 
 // Synchronized Updates spec, designed to avoid tearing during renders
 // https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec
-const (
-	bsu = '\x1bP=1s\x1b\\'
-	esu = '\x1bP=2s\x1b\\'
-)
+const bsu = '\x1bP=1s\x1b\\'
+
+const esu = '\x1bP=2s\x1b\\'
 
 // write puts the string `s` into the print buffer.
 [inline]

vlib/term/ui/ui_test.v

@@ -0,0 +1,8 @@
+import term.ui
+
+// This test just ensures that programs importing term.ui can compile
+
+fn test_a_simple_term_ui_program_can_be_compiled() {
+	println(ui.color_table)
+	assert true
+}