1 files changed, 124 insertions, 0 deletions
diff --git a/maildrop/alarm.C b/maildrop/alarm.C
new file mode 100644
index 0000000..f65005a
--- /dev/null
+++ b/maildrop/alarm.C
@@ -0,0 +1,124 @@
+#include	"config.h"
+#include	<iostream>
+
+
+#if HAVE_UNISTD_H
+#include	<unistd.h>
+#else
+extern "C" long alarm(long);
+#endif
+
+#include	<signal.h>
+#include	"alarm.h"
+
+Alarm *Alarm::first=0;
+Alarm *Alarm::last=0;
+
+Alarm::~Alarm()
+{
+	Cancel();
+}
+
+void Alarm::Unlink()
+{
+	set_interval=0;
+	if (prev)	prev->next=next;
+	else		first=next;
+	if (next)	next->prev=prev;
+	else		last=prev;
+}
+
+void Alarm::cancel_sig(unsigned seconds_left)
+{
+Alarm	*p;
+Alarm	*alarm_chain=0;
+
+	while ((p=first) != 0 && p->set_interval <= seconds_left)
+			// Marginal case
+	{
+		p->Unlink();
+		p->next=alarm_chain;
+		alarm_chain=p;
+	}
+
+	for (p=first; p; p=p->next)
+		p->set_interval -= seconds_left;
+
+	while ((p=alarm_chain) != 0)
+	{
+		alarm_chain=p->next;
+		p->handler();
+	}
+}
+
+void Alarm::set_sig()
+{
+	if (!first)	return;
+	signal(SIGALRM, &Alarm::alarm_func);
+	alarm(first->set_interval);
+}
+
+RETSIGTYPE Alarm::alarm_func(int)
+{
+	if (first)	cancel_sig(first->set_interval);
+	set_sig();
+
+#if RETSIGTYPE != void
+	return (0);
+#endif
+}
+
+unsigned Alarm::sig_left()
+{
+	if (!first)	return (0);
+
+unsigned n=alarm(0);
+
+	return (n ? n <= first->set_interval ? first->set_interval - n:0:0);
+}
+
+void Alarm::Set(unsigned nseconds)
+{
+	Cancel();		// Just in case
+	if (nseconds == 0)
+	{
+		handler();	// Fooey.
+		return;
+	}
+
+	cancel_sig(sig_left());
+
+Alarm	*p;
+
+	for (p=first; p; p=p->next)
+		if (p->set_interval > nseconds)
+			break;
+
+	if (!p)
+	{
+		next=0;
+		if ((prev=last) != 0)
+			prev->next=this;
+		else
+			first=this;
+		last=this;
+	}
+	else
+	{
+		if ((prev=p->prev) != 0)
+			prev->next=this;
+		else
+			first=this;
+		next=p;
+		p->prev=this;
+	}
+	set_interval=nseconds;
+	set_sig();
+}
+
+void Alarm::Cancel()
+{
+	cancel_sig(sig_left());
+	if (set_interval) Unlink();
+	set_sig();
+}