PLUGINS: add ELF memory manager to solve fragmentation

Following lordhoto's suggestion, I implemented a simple allocator that grabs the size of the biggest available plugin in memory. This is an elegant solution to the fragmentation problem, with the caveat that memory is wasted. As such, it's not suited for the DS, so I added a #define to disable it there.

svn-id: r55009

1 files changed, 36 insertions, 0 deletions

diff --git a/backends/plugins/elf/elf-provider.cpp b/backends/plugins/elf/elf-provider.cpp
index b241379934..393010fd6f 100644
--- a/backends/plugins/elf/elf-provider.cpp
+++ b/backends/plugins/elf/elf-provider.cpp
@@ -33,6 +33,7 @@
 
 #include "backends/plugins/elf/elf-provider.h"
 #include "backends/plugins/dynamic-plugin.h"
+#include "backends/plugins/elf/memory-manager.h"
 
 #include "common/debug.h"
 #include "common/fs.h"
@@ -96,6 +97,17 @@ DynamicPlugin::VoidFunc ELFPlugin::findSymbol(const char *symbol) {
 	return tmp;
 }
 
+ /**
+  * Test the size of the plugin.
+  */
+void ELFPlugin::trackSize() {
+	// All we need to do is create our object, track its size, then delete it
+	DLObject *obj = makeDLObject();
+	
+	obj->trackSize(_filename.c_str());
+	delete obj;
+}
+
 bool ELFPlugin::loadPlugin() {
 	assert(!_dlHandle);
 
@@ -162,6 +174,30 @@ void ELFPlugin::unloadPlugin() {
 	}
 }
 
+ /**
+  * We override this function in FilePluginProvider to allow the single
+  * plugin method to create a non-fragmenting memory allocation. We take
+  * the plugins found and tell the memory manager to allocate space for
+  * them.
+  */
+PluginList ELFPluginProvider::getPlugins() {
+	PluginList pl = FilePluginProvider::getPlugins();
+
+#if defined(ONE_PLUGIN_AT_A_TIME) && !defined(ELF_NO_MEM_MANAGER) 	
+	// 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
+	ELFMemMan.allocateHeap();
+#endif	
+	
+	return pl;
+}
+
 bool ELFPluginProvider::isPluginFilename(const Common::FSNode &node) const {
 	// Check the plugin suffix
 	Common::String filename = node.getName();