Saveload: Adjust flags for saving using upstream chunks

src/sl/saveload.cpp

@@ -387,6 +387,9 @@ static void SlNullPointers()
 	SlXvSetCurrentState();
 
 	for (auto &ch : ChunkHandlers()) {
+		if (ch.special_proc != nullptr) {
+			if (ch.special_proc(ch.id, CSLSO_PRE_PTRS) == CSLSOR_LOAD_CHUNK_CONSUMED) continue;
+		}
 		if (ch.ptrs_proc != nullptr) {
 			DEBUG(sl, 3, "Nulling pointers for %c%c%c%c", ch.id >> 24, ch.id >> 16, ch.id >> 8, ch.id);
 			ch.ptrs_proc();
@@ -2312,14 +2315,18 @@ static void SlLoadCheckChunk(const ChunkHandler *ch)
  */
 static void SlSaveChunk(const ChunkHandler &ch)
 {
-	if (ch.type == CH_UPSTREAM_SAVE) {
-		SaveLoadVersion old_ver = _sl_version;
-		_sl_version = MAX_LOAD_SAVEGAME_VERSION;
-		auto guard = scope_guard([&]() {
-			_sl_version = old_ver;
-		});
-		upstream_sl::SlSaveChunkChunkByID(ch.id);
-		return;
+	if (ch.special_proc != nullptr) {
+		ChunkSaveLoadSpecialOpResult result = ch.special_proc(ch.id, CSLSO_SHOULD_SAVE_CHUNK);
+		if (result == CSLSOR_DONT_SAVE_CHUNK) return;
+		if (result == CSLSOR_UPSTREAM_SAVE_CHUNK) {
+			SaveLoadVersion old_ver = _sl_version;
+			_sl_version = MAX_LOAD_SAVEGAME_VERSION;
+			auto guard = scope_guard([&]() {
+				_sl_version = old_ver;
+			});
+			upstream_sl::SlSaveChunkChunkByID(ch.id);
+			return;
+		}
 	}
 
 	ChunkSaveLoadProc *proc = ch.save_proc;
@@ -2327,10 +2334,6 @@ static void SlSaveChunk(const ChunkHandler &ch)
 	/* Don't save any chunk information if there is no save handler. */
 	if (proc == nullptr) return;
 
-	if (ch.special_proc != nullptr) {
-		if (ch.special_proc(ch.id, CSLSO_SHOULD_SAVE_CHUNK) == CSLSOR_DONT_SAVE_CHUNK) return;
-	}
-
 	SlWriteUint32(ch.id);
 	DEBUG(sl, 2, "Saving chunk %c%c%c%c", ch.id >> 24, ch.id >> 16, ch.id >> 8, ch.id);
 
@@ -2449,6 +2452,9 @@ static void SlFixPointers()
 	_sl.action = SLA_PTRS;
 
 	for (auto &ch : ChunkHandlers()) {
+		if (ch.special_proc != nullptr) {
+			if (ch.special_proc(ch.id, CSLSO_PRE_PTRS) == CSLSOR_LOAD_CHUNK_CONSUMED) continue;
+		}
 		if (ch.ptrs_proc != nullptr) {
 			DEBUG(sl, 3, "Fixing pointers for %c%c%c%c", ch.id >> 24, ch.id >> 16, ch.id >> 8, ch.id);
 			ch.ptrs_proc();

src/sl/saveload.h

@@ -83,12 +83,14 @@ void SlUnreachablePlaceholder();
 enum ChunkSaveLoadSpecialOp {
 	CSLSO_PRE_LOAD,
 	CSLSO_PRE_LOADCHECK,
+	CSLSO_PRE_PTRS,
 	CSLSO_SHOULD_SAVE_CHUNK,
 };
 enum ChunkSaveLoadSpecialOpResult {
 	CSLSOR_NONE,
 	CSLSOR_LOAD_CHUNK_CONSUMED,
 	CSLSOR_DONT_SAVE_CHUNK,
+	CSLSOR_UPSTREAM_SAVE_CHUNK,
 };
 typedef ChunkSaveLoadSpecialOpResult ChunkSaveLoadSpecialProc(uint32, ChunkSaveLoadSpecialOp);
 
@@ -99,7 +101,7 @@ enum ChunkType {
 	CH_SPARSE_ARRAY = 2,
 	CH_EXT_HDR      = 15, ///< Extended chunk header
 
-	CH_UPSTREAM_SAVE = 0x80,
+	CH_UNUSED = 0x80,
 };
 
 /** Handlers and description of chunk. */
@@ -135,15 +137,11 @@ namespace upstream_sl {
 
 		ChunkHandler ch = {
 			id,
-			nullptr,
 			SlUnreachablePlaceholder,
-			[]() {
-				SlExecWithSlVersion(F::GetLoadVersion(), []() {
-					SlFixPointerChunkByID(id);
-				});
-			},
 			SlUnreachablePlaceholder,
-			CH_UPSTREAM_SAVE
+			SlUnreachablePlaceholder,
+			SlUnreachablePlaceholder,
+			CH_UNUSED
 		};
 		ch.special_proc = [](uint32 chunk_id, ChunkSaveLoadSpecialOp op) -> ChunkSaveLoadSpecialOpResult {
 			assert(id == chunk_id);
@@ -158,6 +156,13 @@ namespace upstream_sl {
 						SlLoadCheckChunkByID(id);
 					});
 					return CSLSOR_LOAD_CHUNK_CONSUMED;
+				case CSLSO_PRE_PTRS:
+					SlExecWithSlVersion(F::GetLoadVersion(), []() {
+						SlFixPointerChunkByID(id);
+					});
+					return CSLSOR_LOAD_CHUNK_CONSUMED;
+				case CSLSO_SHOULD_SAVE_CHUNK:
+					return CSLSOR_UPSTREAM_SAVE_CHUNK;
 				default:
 					return CSLSOR_NONE;
 			}