Allow the user to delete a dive computer from a dive

This can't be the only dive computer, of course. Goes nicely with the
ability to reprder them.

Fixes #551

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

dive.c

@@ -20,26 +20,6 @@ static const char *default_tags[] = {
 	QT_TRANSLATE_NOOP("gettextFromC", "deco")
 };
 
-void make_first_dc()
-{
-	struct divecomputer *dc = &current_dive->dc;
-	struct divecomputer *newdc = malloc(sizeof(*newdc));
-	struct divecomputer *cur_dc = current_dc; /* needs to be in a local variable so the macro isn't re-executed */
-
-	/* skip the current DC in the linked list */
-	while (dc && dc->next != cur_dc)
-		dc = dc->next;
-	if (!dc) {
-		fprintf(stderr, "data inconsistent: can't find the current DC");
-		return;
-	}
-	dc->next = cur_dc->next;
-	*newdc = current_dive->dc;
-	current_dive->dc = *cur_dc;
-	current_dive->dc.next = newdc;
-	free(cur_dc);
-}
-
 void add_event(struct divecomputer *dc, int time, int type, int flags, int value, const char *name)
 {
 	struct event *ev, **p;
@@ -2326,3 +2306,63 @@ void dive_remove_picture(struct dive *d, struct picture *p)
 {
 
 }
+
+/* this always acts on the current divecomputer of the current dive */
+void make_first_dc()
+{
+	struct divecomputer *dc = &current_dive->dc;
+	struct divecomputer *newdc = malloc(sizeof(*newdc));
+	struct divecomputer *cur_dc = current_dc; /* needs to be in a local variable so the macro isn't re-executed */
+
+	/* skip the current DC in the linked list */
+	while (dc && dc->next != cur_dc)
+		dc = dc->next;
+	if (!dc) {
+		fprintf(stderr, "data inconsistent: can't find the current DC");
+		return;
+	}
+	dc->next = cur_dc->next;
+	*newdc = current_dive->dc;
+	current_dive->dc = *cur_dc;
+	current_dive->dc.next = newdc;
+	free(cur_dc);
+}
+
+/* always acts on the current dive */
+int count_divecomputers(void)
+{
+	int ret = 1;
+	struct divecomputer *dc = current_dive->dc.next;
+	while (dc) {
+		ret++;
+		dc = dc->next;
+	}
+	return ret;
+}
+
+/* always acts on the current dive */
+void delete_current_divecomputer(void)
+{
+	struct divecomputer *dc = current_dc;
+
+	if (dc == &current_dive->dc) {
+		/* remove the first one, so copy the second one in place of the first and free the second one
+		 * be careful about freeing the no longer needed structures - since we copy things around we can't use free_dc()*/
+		struct divecomputer *fdc = dc->next;
+		free(dc->sample);
+		free((void *)dc->model);
+		free_events(dc->events);
+		memcpy(dc, fdc, sizeof(struct divecomputer));
+		free(fdc);
+	} else {
+		struct divecomputer *pdc = &current_dive->dc;
+		while (pdc->next != dc && pdc->next)
+			pdc = pdc->next;
+		if (pdc->next == dc) {
+			pdc->next = dc->next;
+			free_dc(dc);
+		}
+	}
+	if (dc_number == count_divecomputers())
+		dc_number--;
+}

dive.h

@@ -456,6 +456,8 @@ static inline struct divecomputer *get_dive_dc(struct dive *dive, int nr)
 }
 
 extern void make_first_dc(void);
+extern int count_divecomputers(void);
+extern void delete_current_divecomputer(void);
 
 /*
  * Iterate over each dive, with the first parameter being the index

qt-ui/profile/profilewidget2.cpp

@@ -873,10 +873,14 @@ void ProfileWidget2::contextMenuEvent(QContextMenuEvent *event)
 			parentItem = parentItem->parentItem();
 		}
 		if (isDCName) {
-			if (dc_number == 0)
+			if (dc_number == 0 && count_divecomputers() == 1)
+				// nothing to do, can't delete or reorder
 				return;
 			// create menu to show when right clicking on dive computer name
-			m.addAction(tr("Make first divecomputer"), this, SLOT(makeFirstDC()));
+			if (dc_number > 0)
+				m.addAction(tr("Make first divecomputer"), this, SLOT(makeFirstDC()));
+			if (count_divecomputers() > 1)
+				m.addAction(tr("Delete this divecomputer"), this, SLOT(deleteCurrentDC()));
 			m.exec(event->globalPos());
 			// don't show the regular profile context menu
 			return;
@@ -929,6 +933,15 @@ void ProfileWidget2::contextMenuEvent(QContextMenuEvent *event)
 	m.exec(event->globalPos());
 }
 
+void ProfileWidget2::deleteCurrentDC()
+{
+	delete_current_divecomputer();
+	mark_divelist_changed(true);
+	// we need to force it since it's likely the same dive and same dc_number - but that's a different dive computer now
+	forceReplot = true;
+	MainWindow::instance()->refreshDisplay();
+}
+
 void ProfileWidget2::makeFirstDC()
 {
 	make_first_dc();

qt-ui/profile/profilewidget2.h

@@ -90,6 +90,7 @@ slots: // Necessary to call from QAction's signals.
 	void removeEvent();
 	void editName();
 	void makeFirstDC();
+	void deleteCurrentDC();
 	void pointInserted(const QModelIndex &parent, int start, int end);
 	void pointsRemoved(const QModelIndex &, int start, int end);
 	void plotPictures();