Change: rework GLOG chunk to be more like the rest

Basically it is very similar to Vehicles, where there first is
a type field, followed by data of that type. So this commit makes
it looks like how Vehicles solved that.
This removes a lot of custom "keeping track of length" stuff.

3 files changed, 270 insertions, 100 deletions

diff --git a/src/gamelog.h b/src/gamelog.h
index d9e0dd529..cfa6c626a 100644
--- a/src/gamelog.h
+++ b/src/gamelog.h
@@ -13,7 +13,7 @@
 #include "newgrf_config.h"
 
 /** The actions we log. */
-enum GamelogActionType {
+enum GamelogActionType : uint8 {
 	GLAT_START,        ///< Game created
 	GLAT_LOAD,         ///< Game loaded
 	GLAT_GRF,          ///< GRF changed
diff --git a/src/gamelog_internal.h b/src/gamelog_internal.h
index 2b5c6ed0a..fb7c88e48 100644
--- a/src/gamelog_internal.h
+++ b/src/gamelog_internal.h
@@ -13,7 +13,7 @@
 #include "gamelog.h"
 
 /** Type of logged change */
-enum GamelogChangeType {
+enum GamelogChangeType : uint8 {
 	GLCT_MODE,        ///< Scenario editor x Game, different landscape
 	GLCT_REVISION,    ///< Changed game revision string
 	GLCT_OLDVER,      ///< Loaded from savegame without logged data
diff --git a/src/saveload/gamelog_sl.cpp b/src/saveload/gamelog_sl.cpp
index 6569954f8..9f7f4f140 100644
--- a/src/saveload/gamelog_sl.cpp
+++ b/src/saveload/gamelog_sl.cpp
@@ -15,147 +15,317 @@
 
 #include "../safeguards.h"
 
-static const SaveLoad _glog_action_desc[] = {
-	SLE_VAR(LoggedAction, tick,              SLE_UINT16),
-};
 
-static const SaveLoad _glog_mode_desc[] = {
-	SLE_VAR(LoggedChange, mode.mode,         SLE_UINT8),
-	SLE_VAR(LoggedChange, mode.landscape,    SLE_UINT8),
-};
+class SlGamelogMode : public DefaultSaveLoadHandler<SlGamelogMode, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, mode.mode,         SLE_UINT8),
+		SLE_VAR(LoggedChange, mode.landscape,    SLE_UINT8),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_MODE) return;
+		SlObject(lc, this->GetDescription());
+	}
 
-static const SaveLoad _glog_revision_desc[] = {
-	SLE_ARR(LoggedChange, revision.text,     SLE_UINT8,  GAMELOG_REVISION_LENGTH),
-	SLE_VAR(LoggedChange, revision.newgrf,   SLE_UINT32),
-	SLE_VAR(LoggedChange, revision.slver,    SLE_UINT16),
-	SLE_VAR(LoggedChange, revision.modified, SLE_UINT8),
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_oldver_desc[] = {
-	SLE_VAR(LoggedChange, oldver.type,       SLE_UINT32),
-	SLE_VAR(LoggedChange, oldver.version,    SLE_UINT32),
-};
+class SlGamelogRevision : public DefaultSaveLoadHandler<SlGamelogRevision, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_ARR(LoggedChange, revision.text,     SLE_UINT8,  GAMELOG_REVISION_LENGTH),
+		SLE_VAR(LoggedChange, revision.newgrf,   SLE_UINT32),
+		SLE_VAR(LoggedChange, revision.slver,    SLE_UINT16),
+		SLE_VAR(LoggedChange, revision.modified, SLE_UINT8),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_REVISION) return;
+		SlObject(lc, this->GetDescription());
+	}
 
-static const SaveLoad _glog_setting_desc[] = {
-	SLE_STR(LoggedChange, setting.name,      SLE_STR,    128),
-	SLE_VAR(LoggedChange, setting.oldval,    SLE_INT32),
-	SLE_VAR(LoggedChange, setting.newval,    SLE_INT32),
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_grfadd_desc[] = {
-	SLE_VAR(LoggedChange, grfadd.grfid,      SLE_UINT32    ),
-	SLE_ARR(LoggedChange, grfadd.md5sum,     SLE_UINT8,  16),
+class SlGamelogOldver : public DefaultSaveLoadHandler<SlGamelogOldver, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, oldver.type,       SLE_UINT32),
+		SLE_VAR(LoggedChange, oldver.version,    SLE_UINT32),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_OLDVER) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_grfrem_desc[] = {
-	SLE_VAR(LoggedChange, grfrem.grfid,      SLE_UINT32),
+class SlGamelogSetting : public DefaultSaveLoadHandler<SlGamelogSetting, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_STR(LoggedChange, setting.name,      SLE_STR,    128),
+		SLE_VAR(LoggedChange, setting.oldval,    SLE_INT32),
+		SLE_VAR(LoggedChange, setting.newval,    SLE_INT32),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_SETTING) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_grfcompat_desc[] = {
-	SLE_VAR(LoggedChange, grfcompat.grfid,   SLE_UINT32    ),
-	SLE_ARR(LoggedChange, grfcompat.md5sum,  SLE_UINT8,  16),
+class SlGamelogGrfadd : public DefaultSaveLoadHandler<SlGamelogGrfadd, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, grfadd.grfid,      SLE_UINT32    ),
+		SLE_ARR(LoggedChange, grfadd.md5sum,     SLE_UINT8,  16),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_GRFADD) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_grfparam_desc[] = {
-	SLE_VAR(LoggedChange, grfparam.grfid,    SLE_UINT32),
+class SlGamelogGrfrem : public DefaultSaveLoadHandler<SlGamelogGrfrem, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, grfrem.grfid,      SLE_UINT32),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_GRFREM) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_grfmove_desc[] = {
-	SLE_VAR(LoggedChange, grfmove.grfid,     SLE_UINT32),
-	SLE_VAR(LoggedChange, grfmove.offset,    SLE_INT32),
+class SlGamelogGrfcompat : public DefaultSaveLoadHandler<SlGamelogGrfcompat, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, grfcompat.grfid,   SLE_UINT32    ),
+		SLE_ARR(LoggedChange, grfcompat.md5sum,  SLE_UINT8,  16),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_GRFCOMPAT) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_grfbug_desc[] = {
-	SLE_VAR(LoggedChange, grfbug.data,       SLE_UINT64),
-	SLE_VAR(LoggedChange, grfbug.grfid,      SLE_UINT32),
-	SLE_VAR(LoggedChange, grfbug.bug,        SLE_UINT8),
+class SlGamelogGrfparam : public DefaultSaveLoadHandler<SlGamelogGrfparam, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, grfparam.grfid,    SLE_UINT32),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_GRFPARAM) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoad _glog_emergency_desc[] = {
-	SLE_CONDNULL(0, SL_MIN_VERSION, SL_MIN_VERSION), // Just an empty list, to keep the rest of the code easier.
+class SlGamelogGrfmove : public DefaultSaveLoadHandler<SlGamelogGrfmove, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, grfmove.grfid,     SLE_UINT32),
+		SLE_VAR(LoggedChange, grfmove.offset,    SLE_INT32),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_GRFMOVE) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static const SaveLoadTable _glog_desc[] = {
-	_glog_mode_desc,
-	_glog_revision_desc,
-	_glog_oldver_desc,
-	_glog_setting_desc,
-	_glog_grfadd_desc,
-	_glog_grfrem_desc,
-	_glog_grfcompat_desc,
-	_glog_grfparam_desc,
-	_glog_grfmove_desc,
-	_glog_grfbug_desc,
-	_glog_emergency_desc,
+class SlGamelogGrfbug : public DefaultSaveLoadHandler<SlGamelogGrfbug, LoggedChange> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_VAR(LoggedChange, grfbug.data,       SLE_UINT64),
+		SLE_VAR(LoggedChange, grfbug.grfid,      SLE_UINT32),
+		SLE_VAR(LoggedChange, grfbug.bug,        SLE_UINT8),
+	};
+
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_GRFBUG) return;
+		SlObject(lc, this->GetDescription());
+	}
+
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
 };
 
-static_assert(lengthof(_glog_desc) == GLCT_END);
+static bool _is_emergency_save = true;
 
-static void Load_GLOG_common(LoggedAction *&gamelog_action, uint &gamelog_actions)
-{
-	assert(gamelog_action == nullptr);
-	assert(gamelog_actions == 0);
+class SlGamelogEmergency : public DefaultSaveLoadHandler<SlGamelogEmergency, LoggedChange> {
+public:
+	/* We need to store something, so store a "true" value. */
+	inline static const SaveLoad description[] = {
+		SLEG_CONDVAR(_is_emergency_save, SLE_BOOL, SLV_RIFF_TO_ARRAY, SL_MAX_VERSION),
+	};
 
-	byte type;
-	while ((type = SlReadByte()) != GLAT_NONE) {
-		if (type >= GLAT_END) SlErrorCorrupt("Invalid gamelog action type");
-		GamelogActionType at = (GamelogActionType)type;
+	void GenericSaveLoad(LoggedChange *lc) const
+	{
+		if (lc->ct != GLCT_EMERGENCY) return;
 
-		gamelog_action = ReallocT(gamelog_action, gamelog_actions + 1);
-		LoggedAction *la = &gamelog_action[gamelog_actions++];
+		_is_emergency_save = true;
+		SlObject(lc, this->GetDescription());
+	}
 
-		la->at = at;
+	void Save(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void Load(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+	void LoadCheck(LoggedChange *lc) const override { this->GenericSaveLoad(lc); }
+};
 
-		SlObject(la, _glog_action_desc); // has to be saved after 'DATE'!
-		la->change = nullptr;
-		la->changes = 0;
+class SlGamelogAction : public DefaultSaveLoadHandler<SlGamelogAction, LoggedAction> {
+public:
+	inline static const SaveLoad description[] = {
+		SLE_SAVEBYTE(LoggedChange, ct),
+		SLEG_STRUCT(SlGamelogMode),
+		SLEG_STRUCT(SlGamelogRevision),
+		SLEG_STRUCT(SlGamelogOldver),
+		SLEG_STRUCT(SlGamelogSetting),
+		SLEG_STRUCT(SlGamelogGrfadd),
+		SLEG_STRUCT(SlGamelogGrfrem),
+		SLEG_STRUCT(SlGamelogGrfcompat),
+		SLEG_STRUCT(SlGamelogGrfparam),
+		SLEG_STRUCT(SlGamelogGrfmove),
+		SLEG_STRUCT(SlGamelogGrfbug),
+		SLEG_STRUCT(SlGamelogEmergency),
+	};
+
+	void Save(LoggedAction *la) const override
+	{
+		SlSetStructListLength(la->changes);
 
-		while ((type = SlReadByte()) != GLCT_NONE) {
-			if (type >= GLCT_END) SlErrorCorrupt("Invalid gamelog change type");
-			GamelogChangeType ct = (GamelogChangeType)type;
+		const LoggedChange *lcend = &la->change[la->changes];
+		for (LoggedChange *lc = la->change; lc != lcend; lc++) {
+			assert((uint)lc->ct < GLCT_END);
+			SlObject(lc, this->GetDescription());
+		}
+	}
+
+	void Load(LoggedAction *la) const override
+	{
+		if (IsSavegameVersionBefore(SLV_RIFF_TO_ARRAY)) {
+			byte type;
+			while ((type = SlReadByte()) != GLCT_NONE) {
+				if (type >= GLCT_END) SlErrorCorrupt("Invalid gamelog change type");
+				GamelogChangeType ct = (GamelogChangeType)type;
 
-			la->change = ReallocT(la->change, la->changes + 1);
+				la->change = ReallocT(la->change, la->changes + 1);
 
-			LoggedChange *lc = &la->change[la->changes++];
-			/* for SLE_STR, pointer has to be valid! so make it nullptr */
+				LoggedChange *lc = &la->change[la->changes++];
+				memset(lc, 0, sizeof(*lc));
+				lc->ct = ct;
+
+				SlObject(lc, this->GetDescription());
+			}
+			return;
+		}
+
+		size_t length = SlGetStructListLength(UINT32_MAX);
+		la->change = ReallocT(la->change, length);
+
+		for (size_t i = 0; i < length; i++) {
+			LoggedChange *lc = &la->change[i];
 			memset(lc, 0, sizeof(*lc));
-			lc->ct = ct;
 
-			SlObject(lc, _glog_desc[ct]);
+			lc->ct = (GamelogChangeType)SlReadByte();
+			SlObject(lc, this->GetDescription());
 		}
 	}
-}
 
-static void Save_GLOG()
+	void LoadCheck(LoggedAction *la) const override { this->Load(la); }
+};
+
+static const SaveLoad _gamelog_desc[] = {
+	SLE_CONDVAR(LoggedAction, at,            SLE_UINT8,   SLV_RIFF_TO_ARRAY, SL_MAX_VERSION),
+	SLE_VAR(LoggedAction, tick,              SLE_UINT16),
+	SLEG_STRUCTLIST(SlGamelogAction),
+};
+
+static void Load_GLOG_common(LoggedAction *&gamelog_action, uint &gamelog_actions)
 {
-	const LoggedAction *laend = &_gamelog_action[_gamelog_actions];
-	size_t length = 0;
+	assert(gamelog_action == nullptr);
+	assert(gamelog_actions == 0);
 
-	for (const LoggedAction *la = _gamelog_action; la != laend; la++) {
-		const LoggedChange *lcend = &la->change[la->changes];
-		for (LoggedChange *lc = la->change; lc != lcend; lc++) {
-			assert((uint)lc->ct < lengthof(_glog_desc));
-			length += SlCalcObjLength(lc, _glog_desc[lc->ct]) + 1;
+	if (IsSavegameVersionBefore(SLV_RIFF_TO_ARRAY)) {
+		byte type;
+		while ((type = SlReadByte()) != GLAT_NONE) {
+			if (type >= GLAT_END) SlErrorCorrupt("Invalid gamelog action type");
+
+			gamelog_action = ReallocT(gamelog_action, gamelog_actions + 1);
+			LoggedAction *la = &gamelog_action[gamelog_actions++];
+			memset(la, 0, sizeof(*la));
+
+			la->at = (GamelogActionType)type;
+			SlObject(la, _gamelog_desc);
 		}
-		length += 4;
+		return;
 	}
-	length++;
 
-	SlSetLength(length);
+	while (SlIterateArray() != -1) {
+		gamelog_action = ReallocT(gamelog_action, gamelog_actions + 1);
+		LoggedAction *la = &gamelog_action[gamelog_actions++];
+		memset(la, 0, sizeof(*la));
 
-	for (LoggedAction *la = _gamelog_action; la != laend; la++) {
-		SlWriteByte(la->at);
-		SlObject(la, _glog_action_desc);
+		SlObject(la, _gamelog_desc);
+	}
+}
 
-		const LoggedChange *lcend = &la->change[la->changes];
-		for (LoggedChange *lc = la->change; lc != lcend; lc++) {
-			SlWriteByte(lc->ct);
-			assert((uint)lc->ct < GLCT_END);
-			SlObject(lc, _glog_desc[lc->ct]);
-		}
-		SlWriteByte(GLCT_NONE);
+static void Save_GLOG()
+{
+	const LoggedAction *laend = &_gamelog_action[_gamelog_actions];
+
+	uint i = 0;
+	for (LoggedAction *la = _gamelog_action; la != laend; la++, i++) {
+		SlSetArrayIndex(i);
+		SlObject(la, _gamelog_desc);
 	}
-	SlWriteByte(GLAT_NONE);
 }
 
 static void Load_GLOG()
@@ -169,7 +339,7 @@ static void Check_GLOG()
 }
 
 static const ChunkHandler gamelog_chunk_handlers[] = {
-	{ 'GLOG', Save_GLOG, Load_GLOG, nullptr, Check_GLOG, CH_RIFF }
+	{ 'GLOG', Save_GLOG, Load_GLOG, nullptr, Check_GLOG, CH_ARRAY }
 };
 
 extern const ChunkHandlerTable _gamelog_chunk_handlers(gamelog_chunk_handlers);