Undo: implement rudimentary support for undo of dive-splitting

For this, the core functionality of the split_dive() and
split_dive_at_time() functions were split out into new
split_dive_dont_insert() and split_dive_at_time_dont_insert(),
which do not add the new dives to the log. Thus, the undo-command
can take ownership of these dives, without having to remove them
first.

The split-dive functionality is temporarily made desktop-only
until mobile also supports "UndoObjects".

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

desktop-widgets/divelistview.cpp

@@ -633,12 +633,16 @@ void DiveListView::splitDives()
 	int i;
 	struct dive *dive;
 
+	// Let's collect the dives to be split first, so that we don't catch newly inserted dives!
+	QVector<struct dive *> dives;
 	for_each_dive (i, dive) {
 		if (dive->selected)
-			split_dive(dive);
+			dives.append(dive);
+	}
+	for (struct dive *d: dives) {
+		UndoSplitDives *undoCommand = new UndoSplitDives(d, duration_t{-1});
+		MainWindow::instance()->undoStack->push(undoCommand);
 	}
-	MainWindow::instance()->refreshProfile();
-	MainWindow::instance()->refreshDisplay();
 }
 
 void DiveListView::renumberDives()

desktop-widgets/undocommands.cpp

@@ -180,6 +180,7 @@ void UndoRemoveDivesFromTrip::undo()
 	for (auto &pair: divesToAdd)
 		add_dive_to_trip(pair.first, pair.second);
 	divesToAdd.clear();
+	mark_divelist_changed(true);
 
 	// Finally, do the UI stuff:
 	MainWindow::instance()->refreshDisplay();
@@ -204,3 +205,58 @@ void UndoRemoveDivesFromTrip::redo()
 	// Finally, do the UI stuff:
 	MainWindow::instance()->refreshDisplay();
 }
+
+UndoSplitDives::UndoSplitDives(dive *d, duration_t time)
+{
+	setText(gettextFromC::tr("split dive"));
+
+	// Split the dive
+	dive *new1, *new2;
+	int idx = time.seconds < 0 ?
+		split_dive_dont_insert(d, &new1, &new2) :
+		split_dive_at_time_dont_insert(d, time, &new1, &new2);
+
+	// If this didn't work, reset pointers so that redo() and undo() do nothing
+	if (idx < 0) {
+		diveToSplit = nullptr;
+		divesToUnsplit[0] = divesToUnsplit[1];
+		return;
+	}
+
+	diveToSplit = d;
+	splitDives[0].dive.reset(new1);
+	splitDives[0].trip = d->divetrip;
+	splitDives[0].idx = idx;
+	splitDives[1].dive.reset(new2);
+	splitDives[1].trip = d->divetrip;
+	splitDives[1].idx = idx + 1;
+}
+
+void UndoSplitDives::redo()
+{
+	if (!diveToSplit)
+		return;
+	divesToUnsplit[0] = addDive(splitDives[0]);
+	divesToUnsplit[1] = addDive(splitDives[1]);
+	unsplitDive = removeDive(diveToSplit);
+	mark_divelist_changed(true);
+
+	// Finally, do the UI stuff:
+	MainWindow::instance()->refreshDisplay();
+	MainWindow::instance()->refreshProfile();
+}
+
+void UndoSplitDives::undo()
+{
+	if (!unsplitDive.dive)
+		return;
+	// Note: reverse order with respect to redo()
+	diveToSplit = addDive(unsplitDive);
+	splitDives[1] = removeDive(divesToUnsplit[1]);
+	splitDives[0] = removeDive(divesToUnsplit[0]);
+	mark_divelist_changed(true);
+
+	// Finally, do the UI stuff:
+	MainWindow::instance()->refreshDisplay();
+	MainWindow::instance()->refreshProfile();
+}

desktop-widgets/undocommands.h

@@ -227,4 +227,23 @@ private:
 	std::vector<OwningTripPtr> tripsToAdd;
 };
 
+class UndoSplitDives : public QUndoCommand {
+public:
+	// If time is < 0, split at first surface interval
+	UndoSplitDives(dive *d, duration_t time);
+private:
+	void undo() override;
+	void redo() override;
+
+	// For redo
+	// For each dive to split, we remove one from and put two dives into the backend
+	dive		*diveToSplit;
+	DiveToAdd	 splitDives[2];
+
+	// For undo
+	// For each dive to unsplit, we remove two dives from and add one into the backend
+	DiveToAdd	 unsplitDive;
+	dive		*divesToUnsplit[2];
+};
+
 #endif // UNDOCOMMANDS_H