Prevent gaschange tank icons from using garbage coords.

Tank icons were shown at incorrect spots on the profile
when the DiveEventItem object held a pointer to a struct
event even after the struct event at that address had
been freed.  When internalEvent is a pointer to freed
memory, internalEvent->time.seconds could have all kinds
of crazy values, which get used in member function
DiveEventItem::recalculatePos to place the tank at bad
x coordinates.

The DiveEventItem(s) no longer store a pointer to memory
that they do not own.  This way, no matter how the path of
execution arrives into slot recalculatePos, we never need
fear that the DiveEventItem will dereference a garbage
pointer to a struct event.

Fixes #968

Signed-off-by: K. Heller <pestophagous@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

2 files changed, 8 insertions, 1 deletions

diff --git a/qt-ui/profile/diveeventitem.cpp b/qt-ui/profile/diveeventitem.cpp
index 0bbc84267..083c8b5b8 100644
--- a/qt-ui/profile/diveeventitem.cpp
+++ b/qt-ui/profile/diveeventitem.cpp
@@ -19,6 +19,10 @@ DiveEventItem::DiveEventItem(QObject *parent) : DivePixmapItem(parent),
 	setFlag(ItemIgnoresTransformations);
 }
 
+DiveEventItem::~DiveEventItem()
+{
+	free(internalEvent);
+}
 
 void DiveEventItem::setHorizontalAxis(DiveCartesianAxis *axis)
 {
@@ -48,7 +52,9 @@ void DiveEventItem::setEvent(struct event *ev)
 {
 	if (!ev)
 		return;
-	internalEvent = ev;
+
+	free(internalEvent);
+	internalEvent = clone_event(ev);
 	setupPixmap();
 	setupToolTipString();
 	recalculatePos(true);
diff --git a/qt-ui/profile/diveeventitem.h b/qt-ui/profile/diveeventitem.h
index f358fee6d..9d6ad5d26 100644
--- a/qt-ui/profile/diveeventitem.h
+++ b/qt-ui/profile/diveeventitem.h
@@ -11,6 +11,7 @@ class DiveEventItem : public DivePixmapItem {
 	Q_OBJECT
 public:
 	DiveEventItem(QObject *parent = 0);
+	virtual ~DiveEventItem();
 	void setEvent(struct event *ev);
 	struct event *getEvent();
 	void eventVisibilityChanged(const QString &eventName, bool visible);