hare

commit 904ef3090352080cee6f7a0898cbf32066d3f536
parent 098879d7cd61043130abc1125ec63a1b564e9e31
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sat,  4 Sep 2021 10:51:50 +0200

io: introduce io::unwrapfd

Signed-off-by: Drew DeVault <sir@cmpwn.com>

Diffstat:
M
io/+linux/file.ha
 | 
22
+++++++++++++---------
M
unix/tty/+linux/isatty.ha
 | 
5
++++-
M
unix/tty/+linux/winsize.ha
 | 
5
++++-

3 files changed, 21 insertions(+), 11 deletions(-)
diff --git a/io/+linux/file.ha b/io/+linux/file.ha
@@ -48,16 +48,20 @@ export fn is_file(s: *stream) bool = {
 		|| s.copier == &fd_copy;
 };
 
-// Returns the file descriptor for a given [[file]] or [[stream]]. In the latter
-// case, a non-file input will cause the program to abort. This function is not
+// Returns the file descriptor for a given [[file]]. This function is not
 // portable.
-export fn fd(f: (*file | *stream)) int = match (f) {
-	f: *file => f.fd,
-	f: *stream => {
-		assert(is_file(f));
-		let f = f: *file;
-		yield f.fd;
-	},
+export fn fd(f: *file) int = f.fd;
+
+// Returns the file descriptor for a given [[stream]], returning void if the
+// stream is not backed by a file. This function is not portable.
+export fn unwrapfd(s: *stream) (int | void) = {
+	for (!is_file(s)) {
+		s = match (io::source(s)) {
+			errors::unsupported => return,
+			s: *io::stream => s,
+		};
+	};
+	return fd(s: *file);
 };
 
 fn fd_read(s: *stream, buf: []u8) (size | EOF | error) = {
diff --git a/unix/tty/+linux/isatty.ha b/unix/tty/+linux/isatty.ha
@@ -4,7 +4,10 @@ use os;
 
 // Returns whether the given stream is connected to a terminal.
 export fn isatty(stream: *io::stream) bool = {
-	let fd = io::fd(stream);
+	let fd = match (io::unwrapfd(stream)) {
+		void => return false,
+		fd: int => fd,
+	};
 	let wsz = rt::winsize { ... };
 	return match (rt::ioctl(fd, rt::TIOCGWINSZ, &wsz: *void)) {
 		e: rt::errno => false,
diff --git a/unix/tty/+linux/winsize.ha b/unix/tty/+linux/winsize.ha
@@ -5,7 +5,10 @@ use rt;
 
 // Returns the dimensions of underlying terminal of the stream.
 export fn winsize(tty: *io::stream) (ttysize | error) = {
-	let fd = io::fd(tty);
+	let fd = match (io::unwrapfd(tty)) {
+		void => return errors::unsupported,
+		fd: int => fd,
+	};
 	let wsz = rt::winsize { ... };
 	return match (rt::ioctl(fd, rt::TIOCGWINSZ, &wsz: *void)) {
 		e: rt::errno => switch (e: int) {