Event driven design

Makefile.am

@@ -4,7 +4,11 @@ AM_CFLAGS=-Wall -Wextra
 AM_CPPFLAGS=-D_GNU_SOURCE
 
 bin_PROGRAMS=pick
-pick_SOURCES=pick.c compat-reallocarray.c compat-strtonum.c compat.h
+pick_SOURCES=compat-reallocarray.c \
+             compat-strtonum.c \
+             compat-xpoll.c \
+             compat.h \
+             pick.c
 pick_CPPFLAGS=$(AM_CPPFLAGS) $(NCURSES_CFLAGS)
 pick_LDADD=$(NCURSES_LIBS)
 

compat-xpoll.c

@@ -0,0 +1,121 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <poll.h>
+
+#include "compat.h"
+
+#ifdef HAVE_BROKEN_POLL
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+static int	tty_peekc(int);
+
+int
+xpoll(struct pollfd *fds, nfds_t nfds, int timeout)
+{
+	static int	state;
+	int		flags, inready, ttyready;
+	int		nready = 0;
+
+	/* XXX filter_choices() poll disabled */
+	if (nfds == 1 && timeout == 0)
+		return 0;
+
+	if (state == 0) {
+		assert(nfds == 2);
+
+		flags = fcntl(fds[0].fd, F_GETFL, 0);
+		if (flags == -1)
+			return -1;
+		flags |= O_NONBLOCK;
+		if (fcntl(fds[0].fd, F_SETFL, flags) == -1)
+			return -1;
+		state++;
+	}
+
+	if (state == 1) {
+		if (timeout < 0)
+			timeout = 100;
+		while (nready == 0) {
+			if (nfds == 1) {
+				state++;
+				break;
+			}
+
+			inready = poll(&fds[1], 1, timeout);
+			if (inready == -1)
+				return -1;
+			nready += inready;
+
+			ttyready = tty_peekc(fds[0].fd);
+			if (ttyready == -1) {
+				return -1;
+			} else if (ttyready > 0) {
+				fds[0].revents = POLLIN;
+				nready++;
+			} else {
+				fds[0].revents = 0;
+			}
+		}
+	}
+
+	if (state == 2) {
+		flags = fcntl(fds[0].fd, F_GETFL, 0);
+		if (flags == -1)
+			return -1;
+		flags &= ~O_NONBLOCK;
+		if (fcntl(fds[0].fd, F_SETFL, flags) == -1)
+			return -1;
+		state++;
+	}
+
+	if (state == 3) {
+		ttyready = tty_peekc(fds[0].fd);
+		if (ttyready == -1) {
+			return -1;
+		} else if (ttyready > 0) {
+			fds[0].revents = POLLIN;
+			nready++;
+		} else {
+			fds[0].revents = 0;
+		}
+	}
+
+	return nready;
+}
+
+static int
+tty_peekc(int fd)
+{
+	extern int	tty_getc_peek;
+	ssize_t		n;
+	unsigned char	c;
+
+	n = read(fd, &c, sizeof(c));
+	if (n == -1) {
+		if (errno == EAGAIN)
+			return 0;
+		return -1;
+	}
+	if (n > 0) {
+		assert(tty_getc_peek == -1);
+		tty_getc_peek = c;
+	}
+	return n;
+}
+
+#else
+
+int
+xpoll(struct pollfd *fds, nfds_t nfds, int timeout)
+{
+	return poll(fds, nfds, timeout);
+}
+
+#endif /* HAVE_BROKEN_POLL */

compat.h

@@ -32,3 +32,5 @@ long long	strtonum(const char *, long long, long long, const char **);
 #endif /* !HAVE_STRTONUM */
 
 #endif /* COMPAT_H */
+
+int xpoll(struct pollfd *fds, nfds_t nfds, int timeout);

config.h.in

@@ -1,5 +1,8 @@
 /* config.h.in.  Generated from configure.ac by autoheader.  */
 
+/* Define if poll does not support character devices */
+#undef HAVE_BROKEN_POLL
+
 /* Define if ncursesw is available */
 #undef HAVE_NCURSESW_H
 

configure.ac

@@ -2,6 +2,7 @@ AC_PREREQ([2.61])
 AC_INIT([pick], [2.0.2], [pick-maintainers@calleerlandsson.com])
 AM_INIT_AUTOMAKE([subdir-objects])
 AC_CONFIG_HEADERS([config.h])
+AC_CANONICAL_HOST
 AC_PROG_CC
 AM_PROG_CC_C_O
 AC_CHECK_FUNCS([pledge reallocarray strtonum])
@@ -16,7 +17,6 @@ AC_SEARCH_LIBS([setupterm], [curses], [], [
   )
 ])
 AC_DEFUN([AC_MALLOC_OPTIONS], [
-  AC_CANONICAL_HOST
   AC_MSG_CHECKING([for $host_os malloc hardening options])
   case "$host_os" in
   openbsd*) malloc_options="RS";;
@@ -30,5 +30,20 @@ AC_DEFUN([AC_MALLOC_OPTIONS], [
   AC_SUBST([MALLOC_OPTIONS], [$malloc_options])
 ])
 AC_MALLOC_OPTIONS
+AC_DEFUN([AC_BROKEN_POLL], [
+  AC_MSG_CHECKING([for broken poll implementation])
+  case "$host_os" in
+  darwin*) broken=1;;
+  *)       broken=0;;
+  esac
+  if test "$broken" -eq 1; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE([HAVE_BROKEN_POLL], [1], [
+      Define if poll does not support character devices])
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+AC_BROKEN_POLL
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT