Add a checked iterator_to() to AssFile

iterator_to requires that the object be in the list, which is sometimes
not the case when processing a commit which removed the active line or a
selected line. To handle this, add a checked version that returns
Events.end() when it is not in the list rather than crashing.

src/ass_dialogue.cpp

@@ -57,7 +57,10 @@ AssDialogue::AssDialogue() {
 	Id = ++next_id;
 }
 
-AssDialogue::AssDialogue(AssDialogue const& that) : AssDialogueBase(that) {
+AssDialogue::AssDialogue(AssDialogue const& that)
+: AssDialogueBase(that)
+, AssEntryListHook(that)
+{
 	Id = ++next_id;
 }
 

src/ass_file.cpp

@@ -77,6 +77,12 @@ AssFile& AssFile::operator=(AssFile from) {
 	return *this;
 }
 
+EntryList<AssDialogue>::iterator AssFile::iterator_to(AssDialogue& line) {
+	using l = EntryList<AssDialogue>;
+	bool in_list = !l::node_algorithms::inited(l::value_traits::to_node_ptr(line));
+	return in_list ? Events.iterator_to(line) : Events.end();
+}
+
 void AssFile::InsertAttachment(agi::fs::path const& filename) {
 	AssEntryGroup group = AssEntryGroup::GRAPHIC;
 

src/ass_file.h

@@ -72,6 +72,8 @@ public:
 	AssFile& operator=(AssFile from);
 	~AssFile();
 
+	EntryList<AssDialogue>::iterator iterator_to(AssDialogue& line);
+
 	/// @brief Load default file
 	/// @param defline Add a blank line to the file
 	void LoadDefault(bool defline=true);

src/audio_timing_dialogue.cpp

@@ -735,7 +735,7 @@ void AudioTimingControllerDialogue::RegenerateInactiveLines()
 	case 2: // Previous and next lines
 		if (AssDialogue *line = context->selectionController->GetActiveLine())
 		{
-			auto current_line = context->ass->Events.iterator_to(*line);
+			auto current_line = context->ass->iterator_to(*line);
 			if (current_line == context->ass->Events.end())
 				break;
 

src/command/edit.cpp

@@ -780,7 +780,7 @@ static bool try_paste_lines(agi::Context *c) {
 	for (auto& line : parsed)
 		new_selection.insert(&line);
 
-	auto pos = c->ass->Events.iterator_to(*c->selectionController->GetActiveLine());
+	auto pos = c->ass->iterator_to(*c->selectionController->GetActiveLine());
 	c->ass->Events.splice(pos, parsed, parsed.begin(), parsed.end());
 	c->ass->Commit(_("paste"), AssFile::COMMIT_DIAG_ADDREM);
 	c->selectionController->SetSelectionAndActive(std::move(new_selection), new_active);
@@ -811,7 +811,7 @@ struct edit_line_paste final : public Command {
 				ctrl->Paste();
 		}
 		else {
-			auto pos = c->ass->Events.iterator_to(*c->selectionController->GetActiveLine());
+			auto pos = c->ass->iterator_to(*c->selectionController->GetActiveLine());
 			paste_lines(c, false, [=](AssDialogue *new_line) -> AssDialogue * {
 				c->ass->Events.insert(pos, *new_line);
 				return new_line;
@@ -842,7 +842,7 @@ struct edit_line_paste_over final : public Command {
 
 		// Only one line selected, so paste over downwards from the active line
 		if (sel.size() < 2) {
-			auto pos = c->ass->Events.iterator_to(*c->selectionController->GetActiveLine());
+			auto pos = c->ass->iterator_to(*c->selectionController->GetActiveLine());
 
 			paste_lines(c, true, [&](AssDialogue *new_line) -> AssDialogue * {
 				std::unique_ptr<AssDialogue> deleter(new_line);
@@ -1008,7 +1008,7 @@ void split_lines(agi::Context *c, Func&& set_time) {
 
 	AssDialogue *n1 = c->selectionController->GetActiveLine();
 	auto n2 = new AssDialogue(*n1);
-	c->ass->Events.insert(++c->ass->Events.iterator_to(*n1), *n2);
+	c->ass->Events.insert(++c->ass->iterator_to(*n1), *n2);
 
 	std::string orig = n1->Text;
 	n1->Text = boost::trim_right_copy(orig.substr(0, pos));

src/command/grid.cpp

@@ -80,7 +80,7 @@ struct grid_line_next_create final : public Command {
 			newline->End = cur->End + OPT_GET("Timing/Default Duration")->GetInt();
 			newline->Style = cur->Style;
 
-			auto pos = c->ass->Events.iterator_to(*cur);
+			auto pos = c->ass->iterator_to(*cur);
 			c->ass->Events.insert(++pos, *newline);
 			c->ass->Commit(_("line insertion"), AssFile::COMMIT_DIAG_ADDREM);
 			c->selectionController->NextLine();

src/command/subtitle.cpp

@@ -124,7 +124,7 @@ static void insert_subtitle_at_video(agi::Context *c, bool after) {
 	def->End = video_ms + OPT_GET("Timing/Default Duration")->GetInt();
 	def->Style = c->selectionController->GetActiveLine()->Style;
 
-	auto pos = c->ass->Events.iterator_to(*c->selectionController->GetActiveLine());
+	auto pos = c->ass->iterator_to(*c->selectionController->GetActiveLine());
 	if (after) ++pos;
 
 	c->ass->Events.insert(pos, *def);

src/dialog_kara_timing_copy.cpp

@@ -682,11 +682,11 @@ static AssDialogue *find_next(Iterator from, Iterator to, std::string const& sty
 AssDialogue *DialogKanjiTimer::FindNextStyleMatch(AssDialogue *search_from, const std::string &search_style)
 {
 	if (!search_from) return search_from;
-	return find_next(++subs->Events.iterator_to(*search_from), subs->Events.end(), search_style);
+	return find_next(++subs->iterator_to(*search_from), subs->Events.end(), search_style);
 }
 
 AssDialogue *DialogKanjiTimer::FindPrevStyleMatch(AssDialogue *search_from, const std::string &search_style)
 {
 	if (!search_from) return search_from;
-	return find_next(EntryList<AssDialogue>::reverse_iterator(subs->Events.iterator_to(*search_from)), subs->Events.rend(), search_style);
+	return find_next(EntryList<AssDialogue>::reverse_iterator(subs->iterator_to(*search_from)), subs->Events.rend(), search_style);
 }

src/dialog_spellchecker.cpp

@@ -212,7 +212,7 @@ bool DialogSpellChecker::FindNext() {
 	if (CheckLine(active_line, start_pos, &commit_id))
 		return true;
 
-	auto it = context->ass->Events.iterator_to(*active_line);
+	auto it = context->ass->iterator_to(*active_line);
 
 	// Note that it is deliberate that the start line is checked twice, as if
 	// the cursor is past the first misspelled word in the current line, that

src/dialog_timing_processor.cpp

@@ -311,7 +311,7 @@ std::vector<AssDialogue*> DialogTimingProcessor::SortDialogues() {
 	// Check if rows are valid
 	for (auto diag : sorted) {
 		if (diag->Start > diag->End) {
-			int line = std::distance(c->ass->Events.begin(), c->ass->Events.iterator_to(*diag));
+			int line = std::distance(c->ass->Events.begin(), c->ass->iterator_to(*diag));
 			wxMessageBox(
 				wxString::Format(_("One of the lines in the file (%i) has negative duration. Aborting."), line),
 				_("Invalid script"),

src/dialog_translation.cpp

@@ -67,7 +67,7 @@ DialogTranslation::DialogTranslation(agi::Context *c)
 , active_line_connection(c->selectionController->AddActiveLineListener(&DialogTranslation::OnActiveLineChanged, this))
 , active_line(c->selectionController->GetActiveLine())
 , line_count(c->ass->Events.size())
-, line_number(std::distance(c->ass->Events.begin(), c->ass->Events.iterator_to(*active_line)) + 1)
+, line_number(std::distance(c->ass->Events.begin(), c->ass->iterator_to(*active_line)) + 1)
 {
 	SetIcon(GETICON(translation_toolbutton_16));
 
@@ -175,7 +175,7 @@ void DialogTranslation::OnActiveLineChanged(AssDialogue *new_line) {
 	active_line = new_line;
 	blocks = active_line->ParseTags();
 	cur_block = 0;
-	line_number = std::distance(c->ass->Events.begin(), c->ass->Events.iterator_to(*new_line)) + 1;
+	line_number = std::distance(c->ass->Events.begin(), c->ass->iterator_to(*new_line)) + 1;
 
 	if (bad_block(blocks[cur_block]) && !NextBlock()) {
 		wxMessageBox(_("No more lines to translate."));

src/search_replace_engine.cpp

@@ -229,7 +229,7 @@ bool SearchReplaceEngine::FindReplace(bool replace) {
 	auto matches = GetMatcher(settings);
 
 	AssDialogue *line = context->selectionController->GetActiveLine();
-	auto it = context->ass->Events.iterator_to(*line);
+	auto it = context->ass->iterator_to(*line);
 	size_t pos = 0;
 
 	MatchState replace_ms;

src/selection_controller.cpp

@@ -46,7 +46,7 @@ void SelectionController::OnSubtitlesOpen() {
 void SelectionController::OnSubtitlesSave() {
 	if (active_line)
 		context->ass->SaveUIState("Active Line", std::to_string(std::distance(
-			context->ass->Events.begin(), context->ass->Events.iterator_to(*active_line))));
+			context->ass->Events.begin(), context->ass->iterator_to(*active_line))));
 }
 
 void SelectionController::SetSelectedSet(Selection new_selection) {
@@ -68,7 +68,7 @@ void SelectionController::SetSelectionAndActive(Selection new_selection, AssDial
 
 void SelectionController::PrevLine() {
 	if (!active_line) return;
-	auto it = context->ass->Events.iterator_to(*active_line);
+	auto it = context->ass->iterator_to(*active_line);
 	if (it != context->ass->Events.begin()) {
 		--it;
 		SetSelectionAndActive({&*it}, &*it);
@@ -77,7 +77,7 @@ void SelectionController::PrevLine() {
 
 void SelectionController::NextLine() {
 	if (!active_line) return;
-	auto it = context->ass->Events.iterator_to(*active_line);
+	auto it = context->ass->iterator_to(*active_line);
 	if (++it != context->ass->Events.end())
 		SetSelectionAndActive({&*it}, &*it);
 }