(svn r15045) -Add [NoAI API CHANGE]: in info.nut you can now have (optional) a CanLoadFromVersion(version), which should return true/false, to indicate if you can load a savegame made with your AI of version 'version'

-Add [NoAI API CHANGE]: in main.nut the Load() function now should be Load(version, data), where 'version' is the version of your AI which made the savegame
-Codechange [NoAI]: various of function renames to make things more sane
-Add [NoAI]: push the 'version' of the AI through various of layers
-Codechange [NoAI]: various of code cleanups
-Add [NoAI]: store the version of the AI in the savegame too

10 files changed, 61 insertions, 57 deletions

diff --git a/src/ai/ai.hpp b/src/ai/ai.hpp
index bd1c2a907..0bf0a1991 100644
--- a/src/ai/ai.hpp
+++ b/src/ai/ai.hpp
@@ -86,11 +86,11 @@ public:
 	/**
 	 * Load data for an AI from a savegame.
 	 */
-	static void Load(CompanyID company);
+	static void Load(CompanyID company, int version);
 
 	static char *GetConsoleList(char *p, const char *last);
 	static const AIInfoList *GetInfoList();
-	static AIInfo *GetCompanyInfo(const char *name);
+	static AIInfo *FindInfo(const char *name, int version);
 	static bool ImportLibrary(const char *library, const char *class_name, int version, HSQUIRRELVM vm);
 	static void Rescan();
 
diff --git a/src/ai/ai_config.cpp b/src/ai/ai_config.cpp
index b93bf76b4..186d6d6e3 100644
--- a/src/ai/ai_config.cpp
+++ b/src/ai/ai_config.cpp
@@ -9,11 +9,11 @@
 #include "ai_config.hpp"
 #include "ai_info.hpp"
 
-void AIConfig::ChangeAI(const char *name)
+void AIConfig::ChangeAI(const char *name, int version)
 {
 	free((void *)this->name);
 	this->name = (name == NULL) ? NULL : strdup(name);
-	this->info = (name == NULL) ? NULL : AI::GetCompanyInfo(this->name);
+	this->info = (name == NULL) ? NULL : AI::FindInfo(this->name, version);
 	this->version = (info == NULL) ? -1 : info->GetVersion();
 
 	for (SettingValueList::iterator it = this->settings.begin(); it != this->settings.end(); it++) {
@@ -45,7 +45,7 @@ AIInfo *AIConfig::GetInfo()
 
 bool AIConfig::ResetInfo()
 {
-	 this->info = AI::GetCompanyInfo(this->name);
+	 this->info = AI::FindInfo(this->name, this->version);
 	 return this->info != NULL;
 }
 
diff --git a/src/ai/ai_config.hpp b/src/ai/ai_config.hpp
index e6790e22a..90c52b563 100644
--- a/src/ai/ai_config.hpp
+++ b/src/ai/ai_config.hpp
@@ -26,8 +26,10 @@ public:
 
 	/**
 	 * Set another AI to be loaded in this slot.
+	 * @param name The name of the AI.
+	 * @param version The version of the AI to load, or -1 of latest.
 	 */
-	void ChangeAI(const char *name);
+	void ChangeAI(const char *name, int version = -1);
 
 	/**
 	 * When ever the AI Scanner is reloaded, all infos become invalid. This
diff --git a/src/ai/ai_core.cpp b/src/ai/ai_core.cpp
index f0a82f771..3d8fc7707 100644
--- a/src/ai/ai_core.cpp
+++ b/src/ai/ai_core.cpp
@@ -211,7 +211,7 @@ void CcAI(bool success, TileIndex tile, uint32 p1, uint32 p2)
 	}
 }
 
-/* static */ void AI::Load(CompanyID company)
+/* static */ void AI::Load(CompanyID company, int version)
 {
 	if (!_networking || _network_server) {
 		assert(IsValidCompanyID(company));
@@ -219,7 +219,7 @@ void CcAI(bool success, TileIndex tile, uint32 p1, uint32 p2)
 
 		CompanyID old_company = _current_company;
 		_current_company = company;
-		GetCompany(company)->ai_instance->Load();
+		GetCompany(company)->ai_instance->Load(version);
 		_current_company = old_company;
 	} else {
 		/* Read, but ignore, the load data */
@@ -237,9 +237,9 @@ void CcAI(bool success, TileIndex tile, uint32 p1, uint32 p2)
 	return AI::ai_scanner->GetAIInfoList();
 }
 
-/* static */ AIInfo *AI::GetCompanyInfo(const char *name)
+/* static */ AIInfo *AI::FindInfo(const char *name, int version)
 {
-	return AI::ai_scanner->FindAI(name);
+	return AI::ai_scanner->FindInfo(name, version);
 }
 
 /* static */ bool AI::ImportLibrary(const char *library, const char *class_name, int version, HSQUIRRELVM vm)
diff --git a/src/ai/ai_info.cpp b/src/ai/ai_info.cpp
index 80f6f9e8d..e55affaa5 100644
--- a/src/ai/ai_info.cpp
+++ b/src/ai/ai_info.cpp
@@ -70,9 +70,26 @@ const char *AIFileInfo::GetInstanceName()
 	return this->instance_name;
 }
 
-bool AIFileInfo::AllowStartup()
+bool AIFileInfo::CanLoadFromVersion(int version)
 {
-	return true;
+	if (version == -1) return true;
+	if (!this->engine->MethodExists(*this->SQ_instance, "CanLoadFromVersion")) return true;
+
+	HSQUIRRELVM vm = this->engine->GetVM();
+	int top = sq_gettop(vm);
+
+	sq_pushobject(vm, *this->SQ_instance);
+	sq_pushstring(vm, OTTD2FS("CanLoadFromVersion"), -1);
+	sq_get(vm, -2);
+	sq_pushobject(vm, *this->SQ_instance);
+	sq_pushinteger(vm, version);
+	sq_call(vm, 2, SQTrue, SQFalse);
+
+	HSQOBJECT ret;
+	sq_getstackobj(vm, -1, &ret);
+
+	sq_settop(vm, top);
+	return sq_objtobool(&ret);
 }
 
 const char *AIFileInfo::GetDirName()
diff --git a/src/ai/ai_info.hpp b/src/ai/ai_info.hpp
index d50b89584..205e89b38 100644
--- a/src/ai/ai_info.hpp
+++ b/src/ai/ai_info.hpp
@@ -74,7 +74,7 @@ public:
 	/**
 	 * Check if we can start this AI.
 	 */
-	bool AllowStartup();
+	bool CanLoadFromVersion(int version);
 
 	/**
 	 * Get the name of the dir this AI is in.
diff --git a/src/ai/ai_instance.cpp b/src/ai/ai_instance.cpp
index a0612498d..1e57c6496 100644
--- a/src/ai/ai_instance.cpp
+++ b/src/ai/ai_instance.cpp
@@ -592,37 +592,38 @@ void AIInstance::Save()
 	LoadObjects(NULL);
 }
 
-bool AIInstance::Load()
+void AIInstance::Load(int version)
 {
-	HSQUIRRELVM vm = (this->engine == NULL) ? NULL : this->engine->GetVM();
+	if (this->engine == NULL || version == -1) {
+		LoadEmpty();
+		return;
+	}
+	HSQUIRRELVM vm = this->engine->GetVM();
 
 	SlObject(NULL, _ai_byte);
 	/* Check if there was anything saved at all. */
-	if (_ai_sl_byte == 0) return true;
+	if (_ai_sl_byte == 0) return;
 	AIObject::SetAllowDoCommand(false);
 
-	if (vm != NULL) {
-		/* Go to the instance-root */
-		sq_pushobject(vm, *this->instance);
-		/* Find the function-name inside the script */
-		sq_pushstring(vm, OTTD2FS("Load"), -1);
-		if (SQ_FAILED(sq_get(vm, -2))) sq_pushnull(vm);
-		sq_pushobject(vm, *this->instance);
-	}
+	/* Go to the instance-root */
+	sq_pushobject(vm, *this->instance);
+	/* Find the function-name inside the script */
+	sq_pushstring(vm, OTTD2FS("Load"), -1);
+	if (SQ_FAILED(sq_get(vm, -2))) sq_pushnull(vm);
+	sq_pushobject(vm, *this->instance);
+	sq_pushinteger(vm, version);
 
 	LoadObjects(vm);
 
-	if (this->engine != NULL) {
-		if (this->engine->MethodExists(*this->instance, "Load")) {
-			sq_call(vm, 2, SQFalse, SQFalse);
-		} else {
-			AILog::Warning("Loading failed: there was data for the AI to load, but the AI does not have a Load() function.");
-		}
+	if (this->engine->MethodExists(*this->instance, "Load")) {
+		sq_call(vm, 3, SQFalse, SQFalse);
+	} else {
+		AILog::Warning("Loading failed: there was data for the AI to load, but the AI does not have a Load() function.");
 	}
 
-	/* Pop 1) the object instance, 2) the function name, 3) the instance again, 4) the table. */
-	if (vm != NULL) sq_pop(vm, 4);
+	/* Pop 1) the object instance, 2) the function name, 3) the instance again, 4) the (null) result. */
+	sq_pop(vm, 4);
 
 	AIObject::SetAllowDoCommand(true);
-	return true;
+	return;
 }
diff --git a/src/ai/ai_instance.hpp b/src/ai/ai_instance.hpp
index d953c3915..5bd3b58b5 100644
--- a/src/ai/ai_instance.hpp
+++ b/src/ai/ai_instance.hpp
@@ -87,9 +87,10 @@ public:
 	/**
 	 * Load data from a savegame and call the AI Load function if it
 	 *   exists.
-	 * @return True if the loading was successfull.
+	 * @param version The version of the AI when saving, or -1 if this was
+	 *  not the original AI saving the game.
 	 */
-	bool Load();
+	void Load(int version);
 
 	/**
 	 * Load and discard data from a savegame.
diff --git a/src/ai/ai_scanner.cpp b/src/ai/ai_scanner.cpp
index 68d53660d..6bcf883e7 100644
--- a/src/ai/ai_scanner.cpp
+++ b/src/ai/ai_scanner.cpp
@@ -344,26 +344,10 @@ AIInfo *AIScanner::SelectRandomAI()
 	AIInfoList::iterator it = this->info_list.begin();
 	for (; pos > 0; pos--) it++;
 	AIInfoList::iterator first_it = it;
-	AIInfo *i = (*it).second;
-
-	if (!i->AllowStartup()) {
-		/* We can't start this AI, try to find the next best */
-		do {
-			it++;
-			if (it == this->info_list.end()) it = this->info_list.begin();
-			/* Back at the beginning? We can't start an AI. */
-			if (first_it == it) {
-				DEBUG(ai, 0, "No suitable AI found, loading 'dummy' AI.");
-				return this->info_dummy;
-			}
-
-			i = (*it).second;
-		} while (!i->AllowStartup());
-	}
-	return i;
+	return (*it).second;
 }
 
-AIInfo *AIScanner::FindAI(const char *name)
+AIInfo *AIScanner::FindInfo(const char *name, int version)
 {
 	if (this->info_list.size() == 0) return NULL;
 	if (name == NULL) return NULL;
@@ -372,7 +356,7 @@ AIInfo *AIScanner::FindAI(const char *name)
 	for (; it != this->info_list.end(); it++) {
 		AIInfo *i = (*it).second;
 
-		if (strcasecmp(name, (*it).first) == 0 && i->AllowStartup()) {
+		if (strcasecmp(name, (*it).first) == 0 && i->CanLoadFromVersion(version)) {
 			return i;
 		}
 	}
@@ -386,8 +370,7 @@ char *AIScanner::GetAIConsoleList(char *p, const char *last)
 	AIInfoList::iterator it = this->info_list.begin();
 	for (; it != this->info_list.end(); it++) {
 		AIInfo *i = (*it).second;
-		if (!i->AllowStartup()) continue;
-		p += seprintf(p, last, "%10s: %s\n", (*it).first, i->GetDescription());
+		p += seprintf(p, last, "%10s (v%d): %s\n", (*it).first, i->GetVersion(), i->GetDescription());
 	}
 	p += seprintf(p, last, "\n");
 
diff --git a/src/ai/ai_scanner.hpp b/src/ai/ai_scanner.hpp
index 2801f556a..672e5102e 100644
--- a/src/ai/ai_scanner.hpp
+++ b/src/ai/ai_scanner.hpp
@@ -42,7 +42,7 @@ public:
 	/**
 	 * Find an AI by name.
 	 */
-	class AIInfo *FindAI(const char *name);
+	class AIInfo *FindInfo(const char *name, int version);
 
 	/**
 	 * Get the list of available AIs for the console.