MOHAWK: Riven: Load only the data files for the current game version

The Steam version is a DVD version, but also has files from the CD
version in the data folder. We need to load only the files from the DVD
version to prevent data inconsistencies.

Also check on startup that all the required datafiles are present.

Possibly fixes #10052.

engines/mohawk/riven.cpp

@@ -139,6 +139,11 @@ Common::Error MohawkEngine_Riven::run() {
 
 	initVars();
 
+	// Check the user has copied all the required datafiles
+	if (!checkDatafiles()) {
+		return Common::kNoGameDataFoundError;
+	}
+
 	// We need to have a cursor source, or the game won't work
 	if (!_cursor->hasSource()) {
 		Common::String message = _("You're missing a Riven executable. The Windows executable is 'riven.exe' or 'rivendmo.exe'. ");
@@ -289,11 +294,6 @@ void MohawkEngine_Riven::pauseEngineIntern(bool pause) {
 // Stack/Card-Related Functions
 
 void MohawkEngine_Riven::changeToStack(uint16 stackId) {
-	// The endings are in reverse order because of the way the 1.02 patch works.
-	// The only "Data3" file is j_Data3.mhk from that patch. Patch files have higher
-	// priorities over the regular files and are therefore loaded and checked first.
-	static const char *endings[] = { "_Data3.mhk", "_Data2.mhk", "_Data1.mhk", "_Data.mhk", "_Sounds.mhk" };
-
 	// Don't change stack to the current stack (if the files are loaded)
 	if (_stack && _stack->getId() == stackId && !_mhk.empty())
 		return;
@@ -318,15 +318,16 @@ void MohawkEngine_Riven::changeToStack(uint16 stackId) {
 	// Get the prefix character for the destination stack
 	char prefix = RivenStacks::getName(stackId)[0];
 
-	// Load any file that fits the patterns
-	for (int i = 0; i < ARRAYSIZE(endings); i++) {
-		Common::String filename = Common::String(prefix) + endings[i];
-
-		MohawkArchive *mhk = new MohawkArchive();
-		if (mhk->openFile(filename))
-			_mhk.push_back(mhk);
-		else
-			delete mhk;
+	// Load files that start with the prefix
+	const char **datafiles = listExpectedDatafiles();
+	for (int i = 0; datafiles[i] != nullptr; i++) {
+		if (datafiles[i][0] == prefix) {
+			MohawkArchive *mhk = new MohawkArchive();
+			if (mhk->openFile(datafiles[i]))
+				_mhk.push_back(mhk);
+			else
+				delete mhk;
+		}
 	}
 
 	// Make sure we have loaded files
@@ -337,6 +338,81 @@ void MohawkEngine_Riven::changeToStack(uint16 stackId) {
 	_stack = constructStackById(stackId);
 }
 
+const char **MohawkEngine_Riven::listExpectedDatafiles() const {
+	// The files are in reverse order because of the way the 1.02 patch works.
+	// The only "Data3" file is j_Data3.mhk from that patch. Patch files have higher
+	// priorities over the regular files and are therefore loaded and checked first.
+	static const char *datafilesDVD[] = {
+			"a_Data.mhk",                  "a_Sounds.mhk",
+			"b_Data.mhk",                  "b_Sounds.mhk",
+			"g_Data.mhk",                  "g_Sounds.mhk",
+			"j_Data2.mhk", "j_Data1.mhk",  "j_Sounds.mhk",
+			"o_Data.mhk",                  "o_Sounds.mhk",
+			"p_Data.mhk",                  "p_Sounds.mhk",
+			"r_Data.mhk",                  "r_Sounds.mhk",
+			"t_Data2.mhk", "t_Data1.mhk",  "t_Sounds.mhk",
+			nullptr
+	};
+
+	static const char *datafilesCD[] = {
+			"a_Data.mhk",                                "a_Sounds.mhk",
+			"b_Data1.mhk", "b_Data.mhk",                 "b_Sounds.mhk",
+			"g_Data.mhk",                                "g_Sounds.mhk",
+			"j_Data3.mhk", "j_Data2.mhk", "j_Data1.mhk", "j_Sounds.mhk",
+			"o_Data.mhk",                                "o_Sounds.mhk",
+			"p_Data.mhk",                                "p_Sounds.mhk",
+			"r_Data.mhk",                                "r_Sounds.mhk",
+			"t_Data.mhk",                                "t_Sounds.mhk",
+			nullptr
+	};
+
+	static const char *datafilesDemo[] = {
+			"a_Data.mhk", "a_Sounds.mhk",
+			"j_Data.mhk", "j_Sounds.mhk",
+			"t_Data.mhk", "t_Sounds.mhk",
+			nullptr
+	};
+
+	const char **datafiles;
+	if (getFeatures() & GF_DEMO) {
+		datafiles = datafilesDemo;
+	} else if (getFeatures() & GF_DVD) {
+		datafiles = datafilesDVD;
+	} else {
+		datafiles = datafilesCD;
+	}
+	return datafiles;
+}
+
+bool MohawkEngine_Riven::checkDatafiles() {
+	Common::String missingFiles;
+
+	const char **datafiles = listExpectedDatafiles();
+	for (int i = 0; datafiles[i] != nullptr; i++) {
+		if (!SearchMan.hasFile(datafiles[i])) {
+			if (strcmp(datafiles[i], "j_Data3.mhk") == 0) {
+				// j_Data3.mhk comes from the 1.02 patch. It is not required to play.
+				continue;
+			}
+
+			if (!missingFiles.empty()) {
+				missingFiles += ", ";
+			}
+			missingFiles += datafiles[i];
+		}
+	}
+
+	if (missingFiles.empty()) {
+		return true;
+	}
+
+	Common::String message = _("You are missing the following required Riven data files:\n") + missingFiles;
+	warning("%s", message.c_str());
+	GUIErrorMessage(message);
+
+	return false;
+}
+
 RivenStack *MohawkEngine_Riven::constructStackById(uint16 id) {
 	switch (id) {
 		case kStackAspit:

engines/mohawk/riven.h

@@ -107,7 +107,11 @@ class MohawkEngine_Riven : public MohawkEngine {
 	void doFrame();
 
 private:
+	// Datafiles
 	MohawkArchive *_extrasFile; // We need a separate handle for the extra data
+	const char **listExpectedDatafiles() const;
+	bool checkDatafiles();
+
 	RivenConsole *_console;
 	RivenSaveLoad *_saveLoad;
 	RivenOptionsDialog *_optionsDialog;