Profile: properly initialize plot_info structures

The create_plot_info_new() function releases old plot data. This
can only work if the plot_info structure was initialized previously.
The ProfileWidget2 did that by a memset, but other parts of the code
did not.

Therefore, introduce a init_plot_info() function and call that when
generating a plot_info struct. Constructors would make this so much
easier - but since this is called from C, we can't use them.

Fixes #2251

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

CHANGELOG.md

@@ -1,4 +1,4 @@
-
+- Desktop: fix crash when saving subtitles or profile picture
 ---
 * Always add new entries at the very top of this file above other existing entries and this note.
 * Use this layout for new entries: `[Area]: [Details about the change] [reference thread / issue]`

core/profile.c

@@ -1318,12 +1318,23 @@ static void debug_print_profiledata(struct plot_info *pi)
 }
 #endif
 
+/*
+ * Initialize a plot_info structure to all-zeroes
+ */
+void init_plot_info(struct plot_info *pi)
+{
+	memset(pi, 0, sizeof(*pi));
+}
+
 /*
  * Create a plot-info with smoothing and ranged min/max
  *
  * This also makes sure that we have extra empty events on both
  * sides, so that you can do end-points without having to worry
  * about it.
+ *
+ * The old data will be freed. Before the first call, the plot
+ * info must be initialized with init_plot_info().
  */
 void create_plot_info_new(struct dive *dive, struct divecomputer *dc, struct plot_info *pi, bool fast, struct deco_state *planner_ds)
 {

core/profile.h

@@ -80,6 +80,7 @@ struct ev_select {
 
 extern void compare_samples(struct plot_data *e1, struct plot_data *e2, char *buf, int bufsize, int sum);
 extern struct plot_info *analyze_plot_info(struct plot_info *pi);
+extern void init_plot_info(struct plot_info *pi);
 extern void create_plot_info_new(struct dive *dive, struct divecomputer *dc, struct plot_info *pi, bool fast, struct deco_state *planner_ds);
 extern void calculate_deco_information(struct deco_state *ds, const struct deco_state *planner_de, const struct dive *dive, const struct divecomputer *dc, struct plot_info *pi, bool print_mode);
 extern struct plot_data *get_plot_details_new(struct plot_info *pi, int time, struct membuffer *);

core/save-profiledata.c

@@ -199,6 +199,7 @@ static void save_profiles_buffer(struct membuffer *b, bool select_only)
 	struct plot_info pi;
 	struct deco_state *planner_deco_state = NULL;
 
+	init_plot_info(&pi);
 	for_each_dive(i, dive) {
 		if (select_only && !dive->selected)
 			continue;
@@ -220,6 +221,7 @@ void save_subtitles_buffer(struct membuffer *b, struct dive *dive, int offset, i
 	struct plot_info pi;
 	struct deco_state *planner_deco_state = NULL;
 
+	init_plot_info(&pi);
 	create_plot_info_new(dive, &dive->dc, &pi, false, planner_deco_state);
 
 	put_format(b, "[Script Info]\n");

profile-widget/profilewidget2.cpp

@@ -148,7 +148,7 @@ ProfileWidget2::ProfileWidget2(QWidget *parent) : QGraphicsView(parent),
 	// would like to be able to ASSERT here that PreferencesDialog::loadSettings has been called.
 	isPlotZoomed = prefs.zoomed_plot; // now it seems that 'prefs' has loaded our preferences
 
-	memset(&plotInfo, 0, sizeof(plotInfo));
+	init_plot_info(&plotInfo);
 
 	setupSceneAndFlags();
 	setupItemSizes();

profile-widget/ruleritem.cpp

@@ -17,7 +17,7 @@ RulerNodeItem2::RulerNodeItem2() :
 	timeAxis(NULL),
 	depthAxis(NULL)
 {
-	memset(&pInfo, 0, sizeof(pInfo));
+	init_plot_info(&pInfo);
 	setRect(-8, -8, 16, 16);
 	setBrush(QColor(0xff, 0, 0, 127));
 	setPen(QColor(Qt::red));

qt-models/diveplotdatamodel.cpp

@@ -10,7 +10,7 @@ DivePlotDataModel::DivePlotDataModel(QObject *parent) :
 	diveId(0),
 	dcNr(0)
 {
-	memset(&pInfo, 0, sizeof(pInfo));
+	init_plot_info(&pInfo);
 	memset(&plot_deco_state, 0, sizeof(struct deco_state));
 }