[studio] Fix Back/Forward navigation actions

src/olympic/studio/applib/src/app.cpp

@@ -155,13 +155,10 @@ static ox::Error run(
 			if (m->id() == moduleId) {
 				for (auto const &c : m->commands()) {
 					if (c.name == subCmd) {
-						auto const kctx = keel::init(
+						OX_REQUIRE(kctx, keel::init(
 							ox::make_unique<ox::PassThroughFS>(projectDir),
-							c.name);
-						if (kctx.error) {
-							return ox::Error{2, "failed to load project directory"};
-						}
-						Project project{*kctx.value, projectDir, projectDataDir};
+							c.name).reoriginate(2, "failed to load project directory"));
+						Project project{*kctx, projectDir, projectDataDir};
 						return c.func(
 							project,
 							args.size() > numCmdArgs ?

src/olympic/studio/applib/src/studioui.cpp

@@ -341,12 +341,14 @@ void StudioUI::drawMenu() noexcept {
 		if (ImGui::BeginMenu("Navigate")) {
 			constexpr auto backShortcut = ox::defines::OS == ox::OS::Darwin ? "Cmd+[" : "Alt+Left Arrow";
 			constexpr auto fwdShortcut = ox::defines::OS == ox::OS::Darwin ? "Cmd+]" : "Alt+Right Arrow";
-			if (ImGui::MenuItem("Back", backShortcut, false, m_sctx.navIdx > 1)) {
+			if (ImGui::MenuItem(
+				"Back", backShortcut, false,
+				m_sctx.navIdx && *m_sctx.navIdx > 1)) {
 				navigateBack(m_sctx);
 			}
 			if (ImGui::MenuItem(
 				"Forward", fwdShortcut, false,
-				m_sctx.navIdx < m_sctx.navStack.size())) {
+				m_sctx.navIdx && *m_sctx.navIdx < m_sctx.navStack.size())) {
 				navigateForward(m_sctx);
 			}
 			ImGui::EndMenu();
@@ -395,11 +397,15 @@ void StudioUI::drawTabs() noexcept {
 				if (m_activeEditorOnLastDraw != e.get()) [[unlikely]] {
 					m_activeEditor->onActivated();
 					if (!m_sctx.navIdx ||
-						(m_sctx.navIdx <= m_sctx.navStack.size() &&
-							m_sctx.navStack[m_sctx.navIdx - 1].filePath != m_activeEditor->itemPath())) {
-						m_sctx.navStack.resize(m_sctx.navIdx);
-						++m_sctx.navIdx;
-						m_sctx.navStack.emplace_back(ox::String{m_activeEditor->itemPath()}, ox::String{""});
+						*m_sctx.navIdx == m_sctx.navStack.size() ||
+						(*m_sctx.navIdx < m_sctx.navStack.size() &&
+							m_sctx.navStack[*m_sctx.navIdx].filePath != m_activeEditor->itemPath())) {
+						auto &navIdx = m_sctx.navIdx.emplace(m_sctx.navIdx.or_value(0u));
+						m_sctx.navStack.resize(navIdx);
+						++navIdx;
+						m_sctx.navStack.emplace_back(
+							ox::String{m_activeEditor->itemPath()},
+							ox::String{});
 					}
 				}
 				if (m_closeActiveTab) [[unlikely]] {

src/olympic/studio/modlib/include/studio/context.hpp

@@ -28,7 +28,7 @@ struct Context {
 			ox::String filePath;
 			ox::String navArgs;
 		};
-		size_t navIdx{};
+		ox::Optional<size_t> navIdx{};
 		ox::Vector<NavPath> navStack;
 		std::function<void(ox::StringParam filePath, ox::StringParam navArgs)> navCallback;
 		Context(StudioUI &pUi, turbine::Context &pTctx) noexcept:

src/olympic/studio/modlib/src/context.cpp

@@ -20,7 +20,7 @@ void navigateTo(Context &ctx, ox::StringParam filePath, ox::StringParam navArgs)
 	//	!err && np->filePath == path && np->navArgs == navArgs.view()) {
 	//	return;
 	//}
-	ctx.navStack.resize(ctx.navIdx + 1);
+	ctx.navStack.resize(ctx.navIdx.or_value(0) + 1);
 	ctx.navStack.emplace_back(ox::String{path}, ox::String{navArgs.view()});
 	try {
 		ctx.navCallback(std::move(path), std::move(navArgs));
@@ -30,31 +30,42 @@ void navigateTo(Context &ctx, ox::StringParam filePath, ox::StringParam navArgs)
 	}
 }
 
+static void validateNavStack(Context &ctx, auto &navStack) noexcept {
+	for (size_t i{}; i < navStack.size(); ++i) {
+		auto const &n = navStack[i];
+		if (!ctx.project->exists(n.filePath)) {
+			std::ignore = navStack.erase(i);
+			continue;
+		}
+		++i;
+	}
+}
+
 void navigateBack(Context &ctx) noexcept {
 	if (!ctx.navIdx) {
 		return;
 	}
-	--ctx.navIdx;
-	while (ctx.navIdx < ctx.navStack.size() && ctx.navIdx) {
-		auto const i = ctx.navIdx - 1;
-		auto const &n = ctx.navStack[i];
-		if (!ctx.project->exists(n.filePath)) {
-			std::ignore = ctx.navStack.erase(i);
-			--ctx.navIdx;
-			continue;
-		}
+	validateNavStack(ctx, ctx.navStack);
+	auto &navIdx = *ctx.navIdx;
+	navIdx = ox::min(navIdx, ctx.navStack.size() - 1);
+	if (navIdx) {
+		--navIdx;
+		auto const &n = ctx.navStack[navIdx];
 		try {
 			ctx.navCallback(n.filePath, n.navArgs);
 		} catch (std::exception const &e) {
 			oxAssert(ctx.navCallback != nullptr, "navCallback is null");
 			oxErrf("navigateForward failed: {}", e.what());
 		}
-		break;
 	}
 }
 
 void navigateForward(Context &ctx) noexcept {
-	auto const nextIdx = ctx.navIdx + 1;
+	if (!ctx.navIdx) {
+		ctx.navIdx.emplace(0u);
+	}
+	auto &navIdx = *ctx.navIdx;
+	auto const nextIdx = navIdx + 1;
 	while (nextIdx < ctx.navStack.size()) {
 		auto const &n = ctx.navStack[nextIdx];
 		try {
@@ -67,7 +78,7 @@ void navigateForward(Context &ctx) noexcept {
 			std::ignore = ctx.navStack.erase(nextIdx);
 			continue;
 		}
-		++ctx.navIdx;
+		++navIdx;
 		break;
 	}
 }