From 2112b1ca2e821e08bbfe6c197856860b6d49b69f Mon Sep 17 00:00:00 2001
From: Lars Henriksen <LarsHenriksen@get2net.dk>
Date: Fri, 14 Sep 2018 21:32:52 +0200
Subject: 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 |  1 +
 src/calcurse.c  | 14 +++++++++
 src/calcurse.h  |  7 +++++
 src/queue.c     | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 112 insertions(+)
 create mode 100644 src/queue.c

(limited to 'src')

diff --git a/src/Makefile.am b/src/Makefile.am
index df6a1ae..9f42ad9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -29,6 +29,7 @@ calcurse_SOURCES = \
 	note.c \
 	notify.c \
 	pcal.c \
+	queue.c \
 	recur.c \
 	sha1.c \
 	sigs.c \
diff --git a/src/calcurse.c b/src/calcurse.c
index 0f6b69a..1b46577 100644
--- a/src/calcurse.c
+++ b/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);
diff --git a/src/calcurse.h b/src/calcurse.h
index 27337fd..be2199a 100644
--- a/src/calcurse.h
+++ b/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 */
diff --git a/src/queue.c b/src/queue.c
new file mode 100644
index 0000000..939b502
--- /dev/null
+++ b/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();
+}
-- 
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