BASE: Fix being unable to run games when using dynamic plugins

When the plugin-engine mapping is not cached in the configuration file,
we were not scanning all the plugins to establish the mapping.

This is a regression from commit: e2d91258b7bfb989dc099f516bb31ceb44554529

This commit reverts the offending commit and implements a proper fix for
the case where there are no dynamic plugins.

Fixes #11300.

3 files changed, 27 insertions, 23 deletions

diff --git a/backends/plugins/elf/elf-provider.cpp b/backends/plugins/elf/elf-provider.cpp
index 6d461c79df..d06c4c1ca1 100644
--- a/backends/plugins/elf/elf-provider.cpp
+++ b/backends/plugins/elf/elf-provider.cpp
@@ -181,15 +181,15 @@ PluginList ELFPluginProvider::getPlugins() {
 	PluginList pl = FilePluginProvider::getPlugins();
 
 #if defined(UNCACHED_PLUGINS) && !defined(ELF_NO_MEM_MANAGER)
-	if (!pl.empty()) {
-		// This static downcast is safe because all of the plugins must
-		// be ELF plugins
-		for (PluginList::iterator p = pl.begin(); p != pl.end(); ++p) {
-			(static_cast<ELFPlugin *>(*p))->trackSize();
-		}
+	// This static downcast is safe because all of the plugins must
+	// be ELF plugins
+	for (PluginList::iterator p = pl.begin(); p != pl.end(); ++p) {
+		(static_cast<ELFPlugin *>(*p))->trackSize();
+	}
 
-		// The Memory Manager should now allocate space based on the information
-		// it collected
+	// The Memory Manager should now allocate space based on the information
+	// it collected
+	if (!pl.empty()) {
 		ELFMemMan.allocateHeap();
 	}
 #endif
diff --git a/backends/plugins/elf/memory-manager.cpp b/backends/plugins/elf/memory-manager.cpp
index 5014718ae8..6e54cb8e29 100644
--- a/backends/plugins/elf/memory-manager.cpp
+++ b/backends/plugins/elf/memory-manager.cpp
@@ -78,9 +78,13 @@ void ELFMemoryManager::trackAlloc(uint32 align, uint32 size) {
 }
 
 void ELFMemoryManager::allocateHeap() {
+	if (!_heapSize) {
+		warning("ELFMemoryManager: Unable to allocate the heap as its size could not be determined.");
+		return;
+	}
+
 	// The memory manager should only allocate once
 	assert (!_heap);
-	assert (_heapSize);
 
 	// clear the list
 	_allocList.clear();
diff --git a/base/plugins.cpp b/base/plugins.cpp
index 490ca33821..cb9d172d0b 100644
--- a/base/plugins.cpp
+++ b/base/plugins.cpp
@@ -357,6 +357,9 @@ void PluginManagerUncached::loadFirstPlugin() {
 bool PluginManagerUncached::loadNextPlugin() {
 	unloadPluginsExcept(PLUGIN_TYPE_ENGINE, NULL, false);
 
+	if (!_currentPlugin)
+		return false;
+
 	for (++_currentPlugin; _currentPlugin != _allEnginePlugins.end(); ++_currentPlugin) {
 		if ((*_currentPlugin)->loadPlugin()) {
 			addToPluginsInMemList(*_currentPlugin);
@@ -533,7 +536,7 @@ DetectionResults EngineManager::detectGames(const Common::FSList &fslist) const
 	DetectedGames candidates;
 	PluginList plugins;
 	PluginList::const_iterator iter;
-	PluginManager::instance().loadFirstPlugin();
+	PluginMan.loadFirstPlugin();
 	do {
 		plugins = getPlugins();
 		// Iterate over all known games and for each check if it might be
@@ -549,7 +552,7 @@ DetectionResults EngineManager::detectGames(const Common::FSList &fslist) const
 			}
 
 		}
-	} while (PluginManager::instance().loadNextPlugin());
+	} while (PluginMan.loadNextPlugin());
 
 	return DetectionResults(candidates);
 }
@@ -641,18 +644,15 @@ const Plugin *EngineManager::findPlugin(const Common::String &engineId) const {
 	}
 
 	// We failed to find it using the engine ID. Scan the list of plugins
-	const PluginList &plugins = getPlugins();
-	if (!plugins.empty()) {
-		PluginMan.loadFirstPlugin();
-		do {
-			plugin = findLoadedPlugin(engineId);
-			if (plugin) {
-				// Update with new plugin file name
-				PluginMan.updateConfigWithFileName(engineId);
-				return plugin;
-			}
-		} while (PluginMan.loadNextPlugin());
-	}
+	PluginMan.loadFirstPlugin();
+	do {
+		plugin = findLoadedPlugin(engineId);
+		if (plugin) {
+			// Update with new plugin file name
+			PluginMan.updateConfigWithFileName(engineId);
+			return plugin;
+		}
+	} while (PluginMan.loadNextPlugin());
 
 	return 0;
 }