[studio] Make navigation code more consistent

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

@@ -30,33 +30,32 @@ 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;
 	}
-	validateNavStack(ctx, ctx.navStack);
 	auto &navIdx = *ctx.navIdx;
 	navIdx = ox::min(navIdx, ctx.navStack.size() - 1);
-	if (navIdx) {
+	while (navIdx && navIdx < ctx.navStack.size()) {
 		--navIdx;
 		auto const &n = ctx.navStack[navIdx];
+		// check for invalid entry
+		if (!ctx.project->exists(n.filePath)) {
+			// remove the invalid entry, then reset and retry
+			auto const err = ctx.navStack.erase(navIdx);
+			if (err.error) {
+				return;
+			}
+			continue;
+		}
+		// entry is valid, do the navigation
 		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;
 	}
 }
 
@@ -68,16 +67,16 @@ void navigateForward(Context &ctx) noexcept {
 	auto const nextIdx = navIdx + 1;
 	while (nextIdx < ctx.navStack.size()) {
 		auto const &n = ctx.navStack[nextIdx];
+		if (!ctx.project->exists(n.filePath)) {
+			std::ignore = ctx.navStack.erase(nextIdx);
+			continue;
+		}
 		try {
 			ctx.navCallback(n.filePath, n.navArgs);
 		} catch (std::exception const &e) {
 			oxAssert(ctx.navCallback != nullptr, "navCallback is null");
 			oxErrf("navigateForward failed: {}", e.what());
 		}
-		if (!ctx.project->exists(n.filePath)) {
-			std::ignore = ctx.navStack.erase(nextIdx);
-			continue;
-		}
 		++navIdx;
 		break;
 	}