Time calculation is broken in datetime panel plugin (patch)

Christian Henz <[email protected]> Mon, 20 Jun 2022 01:44:19 +0200

Newsgroups	gmane.comp.desktop.xfce.devel.version4
Message-ID	<[email protected]>

Hi,

today I built the datetime plugin from master and noticed that it
displayed nonsensical date and time values.

The reason is that in commit dc9e008a55347a22d5d1959a7d34136e78799344
the migration to g_get_real_time() broke the time calculation by mixing
up the units (s/ms/us).

That commit was made over a year ago, but it seems no one has noticed
this? Seems odd for such an obvious issue. Is this plugin deprecated or
something?

Anyway, I have prepared a patch that should fix the issue.

Greetings,
Christian

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fix-time-calculation.patch (text/x-patch, 4.2 KB)

diff --git a/panel-plugin/datetime.c b/panel-plugin/datetime.c
index ac813c3..56c8dd9 100644
--- a/panel-plugin/datetime.c
+++ b/panel-plugin/datetime.c
@@ -46,10 +46,10 @@
  * to occur on the next second or minute
  * when the given update interval is 1000 or 60000 milliseconds, respectively.
  */
-static inline guint datetime_wake_interval(const gint64 current_time,
+static inline guint datetime_wake_interval(const gint64 current_time_ms,
                                            const guint update_interval_ms)
 {
-  return update_interval_ms - (current_time % update_interval_ms);
+  return update_interval_ms - (current_time_ms % update_interval_ms);
 }
 
 /*
@@ -126,10 +126,11 @@ static gboolean datetime_update_cb(gpointer user_data)
 
 void datetime_update(t_datetime *datetime)
 {
-  gint64 timeval;
+  gint64 timeval_ms; /* wall-clock time in milliseconds */
+  time_t timeval_s; /* wall-clock time in seconds */
   gchar *utf8str;
   struct tm *current;
-  guint wake_interval;  /* milliseconds to next update */
+  guint wake_interval_ms;  /* milliseconds to next update */
 
   DBG("wake");
 
@@ -139,8 +140,9 @@ void datetime_update(t_datetime *datetime)
     g_source_remove(datetime->timeout_id);
   }
 
-  timeval = g_get_real_time();
-  current = localtime((time_t *)&timeval);
+  timeval_ms = g_get_real_time() / 1000;
+  timeval_s = timeval_ms / 1000;
+  current = localtime(&timeval_s);
 
   if (datetime->layout != LAYOUT_TIME &&
       datetime->date_format != NULL && GTK_IS_LABEL(datetime->date_label))
@@ -159,8 +161,8 @@ void datetime_update(t_datetime *datetime)
   }
 
   /* Compute the time to the next update and start the timer. */
-  wake_interval = datetime_wake_interval(timeval, datetime->update_interval);
-  datetime->timeout_id = g_timeout_add(wake_interval, datetime_update_cb, datetime);
+  wake_interval_ms = datetime_wake_interval(timeval_ms, datetime->update_interval_ms);
+  datetime->timeout_id = g_timeout_add(wake_interval_ms, datetime_update_cb, datetime);
 }
 
 static gboolean datetime_tooltip_timer(gpointer user_data)
@@ -188,11 +190,12 @@ static gboolean datetime_query_tooltip(GtkWidget *widget,
                                        GtkTooltip *tooltip,
                                        t_datetime *datetime)
 {
-  gint64 timeval;
+  gint64 timeval_ms; /* wall-clock time in milliseconds */
+  time_t timeval_s; /* wall-clock time in seconds */
   struct tm *current;
   gchar *utf8str;
   gchar *format = NULL;
-  guint wake_interval;  /* milliseconds to next update */
+  guint wake_interval_ms;  /* milliseconds to next update */
 
   switch(datetime->layout)
   {
@@ -209,8 +212,9 @@ static gboolean datetime_query_tooltip(GtkWidget *widget,
   if (format == NULL)
     return FALSE;
 
-  timeval = g_get_real_time();
-  current = localtime((time_t *)&timeval);
+  timeval_ms = g_get_real_time() / 1000;
+  timeval_s = timeval_ms / 1000;
+  current = localtime(&timeval_s);
 
   utf8str = datetime_do_utf8strftime(format, current);
   gtk_tooltip_set_text(tooltip, utf8str);
@@ -223,8 +227,8 @@ static gboolean datetime_query_tooltip(GtkWidget *widget,
      * I think we can afford to inefficiently poll every
      * second while the user keeps the mouse here.
      */
-    wake_interval = datetime_wake_interval(timeval, 1000);
-    datetime->tooltip_timeout_id = g_timeout_add(wake_interval,
+    wake_interval_ms = datetime_wake_interval(timeval_ms, 1000);
+    datetime->tooltip_timeout_id = g_timeout_add(wake_interval_ms,
       datetime_tooltip_timer, datetime);
   }
 
@@ -441,7 +445,7 @@ static void datetime_set_update_interval(t_datetime *datetime)
   }
 
   /* 1000 ms in 1 second */
-  datetime->update_interval = 1000 * (has_seconds ? 1 : 60);
+  datetime->update_interval_ms = 1000 * (has_seconds ? 1 : 60);
 }
 
 /*
diff --git a/panel-plugin/datetime.h b/panel-plugin/datetime.h
index 34ec3e9..e58ccbb 100644
--- a/panel-plugin/datetime.h
+++ b/panel-plugin/datetime.h
@@ -44,7 +44,7 @@ typedef struct {
   GtkWidget *box;
   GtkWidget *date_label;
   GtkWidget *time_label;
-  guint update_interval;  /* time between updates in milliseconds */
+  guint update_interval_ms;  /* time between updates in milliseconds */
   guint timeout_id;
   guint tooltip_timeout_id;
   gulong tooltip_handler_id;