System message queue

The screen and user interaction is managed by the main thread. Other parts of
calcurse (threads) wishing to use the screen or communicate with the user, must
do it via the main thread.

For this purpose the main input loop is extended with a message queue. A thread
may insert a message in the queue. The main thread tests for messages before
listening for user commands. If a message is present, it is displayed (in a popup
window) for the user to acknowledge. Depending on the message other actions may
be performed, e.g. the message could be turned into a "system appointment/event"
and inserted among the usual appointments.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

src/Makefile.am

@@ -29,6 +29,7 @@ calcurse_SOURCES = \
 	note.c \
 	notify.c \
 	pcal.c \
+	queue.c \
 	recur.c \
 	sha1.c \
 	sigs.c \

src/calcurse.c

@@ -619,6 +619,9 @@ int main(int argc, char **argv)
 		io_set_lock();
 	}
 
+	/* System message queue. */
+	que_init();
+
 	/* Begin of interactive mode with ncurses interface. */
 	sigs_init();		/* signal handling init */
 	initscr();		/* start the curses mode */
@@ -702,6 +705,14 @@ int main(int argc, char **argv)
 	for (;;) {
 		int key;
 
+		while (que_ued()) {
+			que_show();
+			que_save();
+			do_storage(0);
+			wins_update(FLAG_ALL);
+			que_rem();
+		}
+
 		if (resize) {
 			resize = 0;
 			wins_reset();
@@ -712,7 +723,10 @@ int main(int argc, char **argv)
 			key_generic_reload();
 		}
 
+		/* Check input loop once every minute. */
+		wtimeout(win[KEY].p, 60000);
 		key = keys_get(win[KEY].p, &count, &reg);
+		wtimeout(win[KEY].p, -1);
 		switch (key) {
 		HANDLE_KEY(KEY_GENERIC_CHANGE_VIEW, key_generic_change_view);
 		HANDLE_KEY(KEY_GENERIC_OTHER_CMD, key_generic_other_cmd);

src/calcurse.h

@@ -1287,4 +1287,11 @@ void wins_erase_status_bar(void);
 void wins_other_status_page();
 void wins_reset_status_page(void);
 
+/* queue.c */
+void que_init(void);
+int que_ued(void);
+struct event *que_ins(char *, time_t, int);
+void que_rem(void);
+void que_show(void);
+void que_save(void);
 #endif /* CALCURSE_H */

src/queue.c

@@ -0,0 +1,90 @@
+#include "calcurse.h"
+
+/*
+ * A queue for calcurse system messages.
+ */
+llist_t sysqueue;
+
+void que_init(void)
+{
+	LLIST_INIT(&sysqueue);
+}
+
+/*
+ * Test for queued system events.
+ */
+int que_ued(void)
+{
+	return sysqueue.head ? 1 : 0;
+}
+
+/*
+ * Insert a system event at the tail of the queue.
+ */
+struct event *que_ins(char *mesg, time_t time, int id)
+{
+	struct event *ev;
+
+	ev = mem_malloc(sizeof(struct event));
+	ev->mesg = mem_strdup(mesg);
+	ev->day = time;
+	ev->id = id;
+	ev->note = NULL;
+	LLIST_ADD(&sysqueue, ev);
+
+	return ev;
+}
+
+/*
+ * Get the system event at the head of the queue.
+ */
+struct event *que_get(void)
+{
+	return sysqueue.head ? sysqueue.head->data : NULL;
+}
+
+/*
+ * Remove the system event at the head of the queue.
+ */
+void que_rem(void)
+{
+	struct event *ev;
+
+	if (!sysqueue.head)
+		return;
+	else
+		ev = sysqueue.head->data;
+	mem_free(ev->mesg);
+	mem_free(ev);
+	LLIST_REMOVE(&sysqueue, sysqueue.head);
+}
+
+/*
+ * Display the system event at the head of the queue in a popup window.
+ */
+void que_show(void)
+{
+	struct event *ev;
+	char *date;
+
+	if (!que_ued())
+		return;
+	ev = que_get();
+	date = date_sec2date_str(ev->day, "%F %T");
+	item_in_popup(date, "", ev->mesg, _("System event"));
+	mem_free(date);
+}
+
+/*
+ * Save the system event at the head of the queue as an appointment.
+ */
+void que_save(void)
+{
+	struct event *ev;
+
+	if (!que_ued())
+		return;
+	ev = que_get();
+	apoint_new(ev->mesg, NULL, ev->day, 0, APOINT_NULL);
+	io_set_modified();
+}