[gnome-shell/wip/mcrha/issue1875: 3/4] calendar: Do less work in hasEvents()

[Florian Müllner <fmuellner src gnome org>]

commit 4ad866e93de8282670ef62bb450d1b28b9312b50
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Apr 2 23:46:48 2020 +0200

    calendar: Do less work in hasEvents()
    
    getEvents() filters all events for the given range and sorts the result.
    
    That's more than we need when checking whether there are any events,
    where we only care that there's at least one event in the range.
    
    Address this by splitting out the event filtering into a generator
    function, so hasEvents() can return after at most one iteration.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1192

 js/ui/calendar.js | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)
---
diff --git a/js/ui/calendar.js b/js/ui/calendar.js
index f38544c8bd..94982cf882 100644
--- a/js/ui/calendar.js
+++ b/js/ui/calendar.js
@@ -323,14 +323,16 @@ class DBusEventSource extends EventSourceBase {
         }
     }
 
-    getEvents(begin, end) {
-        let result = [];
-        for (let n = 0; n < this._events.length; n++) {
-            let event = this._events[n];
-
+    *_getFilteredEvents(begin, end) {
+        for (const event of this._events) {
             if (_dateIntervalsOverlap(event.date, event.end, begin, end))
-                result.push(event);
+                yield event;
         }
+    }
+
+    getEvents(begin, end) {
+        let result = [...this._getFilteredEvents(begin, end)];
+
         result.sort((event1, event2) => {
             // sort events by end time on ending day
             let d1 = event1.date < begin && event1.end <= end ? event1.end : event1.date;
@@ -344,12 +346,8 @@ class DBusEventSource extends EventSourceBase {
         let dayBegin = _getBeginningOfDay(day);
         let dayEnd = _getEndOfDay(day);
 
-        let events = this.getEvents(dayBegin, dayEnd);
-
-        if (events.length == 0)
-            return false;
-
-        return true;
+        const { done } = this._getFilteredEvents(dayBegin, dayEnd).next();
+        return !done;
     }
 });