From 20f9bdfa8ea345aa0038e5e16824a4bcabb630ff Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Sat, 27 Feb 2021 12:50:15 +0200
Subject: [PATCH] os: fixes for os.input(), os.get_raw_stdin(),
 os.get_raw_line() in case of stdin EOF

---
 vlib/builtin/cfns.c.v |  2 +-
 vlib/os/os.v          | 21 ++++++++++++++++-----
 vlib/os/os_c.v        | 29 ++++++++++++++++++-----------
 vlib/term/README.md   | 11 +++++++----
 4 files changed, 42 insertions(+), 21 deletions(-)

diff --git a/vlib/builtin/cfns.c.v b/vlib/builtin/cfns.c.v
index 0907d79f99..5cb47e6e39 100644
--- a/vlib/builtin/cfns.c.v
+++ b/vlib/builtin/cfns.c.v
@@ -263,7 +263,7 @@ fn C._waccess() int
 
 fn C._wremove() int
 
-fn C.ReadConsole() voidptr
+fn C.ReadConsole(in_input_handle voidptr, out_buffer voidptr, in_chars_to_read u32, out_read_chars &u32, in_input_control voidptr) bool
 
 fn C.WriteConsole() voidptr
 
diff --git a/vlib/os/os.v b/vlib/os/os.v
index d0b7548a4a..c3c7341e10 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -200,11 +200,23 @@ pub fn file_name(path string) string {
 	return path.all_after_last(path_separator)
 }
 
-// input returns a one-line string from stdin, after printing a prompt.
-pub fn input(prompt string) string {
+// input_opt returns a one-line string from stdin, after printing a prompt.
+// In the event of error (end of input), it returns `none`.
+pub fn input_opt(prompt string) ?string {
 	print(prompt)
 	flush()
-	return get_line()
+	res := get_raw_line()
+	if res.len > 0 {
+		return res.trim_right('\r\n')
+	}
+	return none
+}
+
+// input returns a one-line string from stdin, after printing a prompt.
+// In the event of error (end of input), it returns '<EOF>'.
+pub fn input(prompt string) string {
+	res := input_opt(prompt) or { return '<EOF>' }
+	return res
 }
 
 // get_line returns a one-line string from stdin
@@ -212,9 +224,8 @@ pub fn get_line() string {
 	str := get_raw_line()
 	$if windows {
 		return str.trim_right('\r\n')
-	} $else {
-		return str.trim_right('\n')
 	}
+	return str.trim_right('\n')
 }
 
 // get_lines returns an array of strings read from from stdin.
diff --git a/vlib/os/os_c.v b/vlib/os/os_c.v
index 0af029a8f3..e48721c41d 100644
--- a/vlib/os/os_c.v
+++ b/vlib/os/os_c.v
@@ -476,14 +476,20 @@ pub fn get_raw_line() string {
 			h_input := C.GetStdHandle(C.STD_INPUT_HANDLE)
 			mut bytes_read := 0
 			if is_atty(0) > 0 {
-				C.ReadConsole(h_input, buf, max_line_chars * 2, C.LPDWORD(&bytes_read),
+				x := C.ReadConsole(h_input, buf, max_line_chars * 2, C.LPDWORD(&bytes_read),
 					0)
+				if !x {
+					return tos(buf, 0)
+				}
 				return string_from_wide2(&u16(buf), bytes_read)
 			}
 			mut offset := 0
 			for {
 				pos := buf + offset
 				res := C.ReadFile(h_input, pos, 1, C.LPDWORD(&bytes_read), 0)
+				if !res && offset == 0 {
+					return tos(buf, 0)
+				}
 				if !res || bytes_read == 0 {
 					break
 				}
@@ -497,15 +503,9 @@ pub fn get_raw_line() string {
 		}
 	} $else {
 		max := size_t(0)
-		mut buf := charptr(0)
+		buf := charptr(0)
 		nr_chars := unsafe { C.getline(&buf, &max, C.stdin) }
-		// defer { unsafe{ free(buf) } }
-		if nr_chars == 0 || nr_chars == -1 {
-			return ''
-		}
-		return unsafe { tos3(buf) }
-		// res := tos_clone(buf)
-		// return res
+		return unsafe { tos(byteptr(buf), if nr_chars < 0 { 0 } else { nr_chars }) }
 	}
 }
 
@@ -527,7 +527,6 @@ pub fn get_raw_stdin() []byte {
 				}
 				buf = v_realloc(buf, offset + block_bytes + (block_bytes - bytes_read))
 			}
-			C.CloseHandle(h_input)
 			return array{
 				element_size: 1
 				data: voidptr(buf)
@@ -536,7 +535,15 @@ pub fn get_raw_stdin() []byte {
 			}
 		}
 	} $else {
-		panic('get_raw_stdin not implemented on this platform...')
+		max := size_t(0)
+		buf := charptr(0)
+		nr_chars := unsafe { C.getline(&buf, &max, C.stdin) }
+		return array{
+			element_size: 1
+			data: voidptr(buf)
+			len: if nr_chars < 0 { 0 } else { nr_chars }
+			cap: int(max)
+		}
 	}
 }
 
diff --git a/vlib/term/README.md b/vlib/term/README.md
index 5a9a42ac30..870822662e 100644
--- a/vlib/term/README.md
+++ b/vlib/term/README.md
@@ -22,15 +22,18 @@ fn main() {
 	term.set_cursor_position(x: width / 2, y: height / 2) // now we point the cursor to the middle of  the terminal
 	println(term.strikethrough(term.bright_green('hello world'))) // Print green text
 	term.set_cursor_position(x: 0, y: height) // Sets the position of the cursor to the bottom of the terminal
-	mut var := os.input('press q to quit: ')
 	// Keep prompting until the user presses the q key
 	for {
-		if var == 'q' {
+		if var := os.input_opt('press q to quit: ') {
+			if var != 'q' {
+				continue
+			}
 			break
-		} else {
-			var = os.input('press q to quit: ')
 		}
+		println('')
+		break
 	}
+	println('Goodbye.')
 }
 ```