Fix various issues with the dive add / edit manual dive code

- get_gas_from_events does NOT always set o2/he. It only updates them IFF
  a matching event is found; so we need to make sure we start out with a
  valid gas mix
- the way we tried to restore the edited dive in case of an edit to a
  manually added that is cancelled was completely bogus. Way too complex
  when we can simply and reliably simply store the dive and then copy it
  back

Fixes #270

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

planner.c

@@ -57,6 +57,8 @@ void set_last_stop(bool last_stop_6m)
 
 void get_gas_from_events(struct divecomputer *dc, int time, int *o2, int *he)
 {
+	// we don't modify the values passed in if nothing is found
+	// so don't call with uninitialized o2/he !
 	struct event *event = dc->events;
 	while (event && event->time.seconds <= time) {
 		if (!strcmp(event->name, "gaschange")) {

qt-ui/diveplanner.cpp

@@ -442,28 +442,30 @@ void DivePlannerPointsModel::loadFromDive(dive* d)
 	 * as soon as the model is modified, it will
 	 * remove all samples from the current dive.
 	 * */
-	struct dive *backupDive = alloc_dive();
-	backupDive->when = current_dive->when; // do we need anything else?
-	copy_samples(current_dive, backupDive);
-	copy_cylinders(current_dive, backupDive);
-	copy_events(current_dive, backupDive);
-	backupSamples.clear();
-	for(int i = 0; i < d->dc.samples-1; i++){
-		backupSamples.push_back( d->dc.sample[i]);
-	}
+	memcpy(&backupDive, current_dive, sizeof(struct dive));
+	copy_samples(current_dive, &backupDive);
+	copy_events(current_dive, &backupDive);
 	copy_cylinders(current_dive, stagingDive); // this way the correct cylinder data is shown
 	CylindersModel::instance()->setDive(stagingDive);
 	int lasttime = 0;
-	Q_FOREACH(const sample &s, backupSamples){
-		int o2 = 0, he = 0;
+	// we start with the first gas and see if it was changed
+	int o2 = backupDive.cylinder[0].gasmix.o2.permille;
+	int he = backupDive.cylinder[0].gasmix.he.permille;
+	for (int i = 0; i < backupDive.dc.samples; i++) {
+		const sample &s = backupDive.dc.sample[i];
 		if (s.time.seconds == 0)
 			continue;
-		get_gas_from_events(&backupDive->dc, lasttime, &o2, &he);
+		get_gas_from_events(&backupDive.dc, lasttime, &o2, &he);
 		plannerModel->addStop(s.depth.mm, s.time.seconds, o2, he, 0);
 		lasttime = s.time.seconds;
 	}
 }
 
+void DivePlannerPointsModel::restoreBackupDive()
+{
+	memcpy(current_dive, &backupDive, sizeof(struct dive));
+}
+
 void DivePlannerPointsModel::copyCylinders(dive *d)
 {
 	copy_cylinders(stagingDive, d);
@@ -1412,18 +1414,6 @@ void DivePlannerPointsModel::createTemporaryPlan()
 #endif
 }
 
-void DivePlannerPointsModel::undoEdition()
-{
-	clear();
-	Q_FOREACH(const sample &s, backupSamples){
-		if (s.time.seconds > 0) {
-			int o2, he;
-			get_gas_from_events(&current_dive->dc, s.time.seconds, &o2, &he);
-			plannerModel->addStop(s.depth.mm, s.time.seconds, o2, he, 0);
-		}
-	}
-}
-
 void DivePlannerPointsModel::deleteTemporaryPlan()
 {
 	deleteTemporaryPlan(diveplan.dp);

qt-ui/diveplanner.h

@@ -61,7 +61,8 @@ public slots:
 	void createTemporaryPlan();
 	void deleteTemporaryPlan();
 	void loadFromDive(dive* d);
-	void undoEdition();
+	void restoreBackupDive();
+
 signals:
 	void planCreated();
 	void planCanceled();
@@ -73,6 +74,7 @@ private:
 	Mode mode;
 	QVector<divedatapoint> divepoints;
 	struct dive *tempDive;
+	struct dive backupDive;
 	void deleteTemporaryPlan(struct divedatapoint *dp);
 	QVector<sample> backupSamples; // For editing added dives.
 	struct dive *stagingDive;

qt-ui/maintab.cpp

@@ -565,7 +565,9 @@ void MainTab::rejectChanges()
 			// clean up
 			DivePlannerPointsModel::instance()->cancelPlan();
 		} else if (lastMode == MANUALLY_ADDED_DIVE ) {
-			DivePlannerPointsModel::instance()->undoEdition(); // that's BOGUS... just copy the original dive back and be done with it...
+			// when we tried to edit a manually added dive, we destroyed
+			// the dive we edited, so let's just restore it from backup
+			DivePlannerPointsModel::instance()->restoreBackupDive();
 		}
 		struct dive *curr = current_dive;
 		ui.notes->setText(notesBackup[curr].notes );