Return the ASCII system stream as unique_ptr to stop a per-load leak

gSystemTextFileStream returned a heap-allocated std::ifstream*; callers
only close()d it and never delete()d, leaking one std::ifstream per ASCII
geometry/material load (and on the not-found / nullptr paths). The leak
grows with geometry reloads, so long interactive sessions accumulate it.

Return std::unique_ptr<std::ifstream> so ownership transfers to the
caller and the stream is closed and freed on scope exit. The three
return IN; sites move the same unique_ptr; return nullptr; constructs an
empty one. Callers drop the now-redundant IN->close() (RAII handles it).

Fixes #132

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: zhaozhiwen

gemc/gsystem/gsystemFactories/text/loadGeometry.cc

@@ -34,7 +34,6 @@ void GSystemTextFactory::loadGeometry(GSystem* system) {
 				gutilities::getStringVectorFromStringWithDelimiter(dbline, "|");
 			system->addGVolume(gvolumePars);
 		}
-
-		IN->close();
+		// IN (unique_ptr<ifstream>) closes the file and frees the stream on scope exit.
 	}
 }

gemc/gsystem/gsystemFactories/text/loadMaterials.cc

@@ -28,7 +28,6 @@ void GSystemTextFactory::loadMaterials(GSystem* system) {
 				gutilities::getStringVectorFromStringWithDelimiter(dbline, "|");
 			system->addGMaterial(gmaterialsPars);
 		}
-
-		IN->close();
+		// IN (unique_ptr<ifstream>) closes the file and frees the stream on scope exit.
 	}
 }

gemc/gsystem/gsystemFactories/text/systemTextFactory.cc

@@ -14,20 +14,21 @@
 
 // cpp
 #include <fstream>
+#include <memory>
 
 // returns the file stream, checking all possible directories.
 // SYSTEMTYPE can be:
 // - GTEXTGEOMTYPE (mandatory, exit if not found)
 // - GTEXTMATSTYPE
-std::ifstream* GSystemTextFactory::gSystemTextFileStream(GSystem* system, const std::string& SYSTEMTYPE) {
+std::unique_ptr<std::ifstream> GSystemTextFactory::gSystemTextFileStream(GSystem* system, const std::string& SYSTEMTYPE) {
 	std::string fileName  = system->getFilePath();
 	std::string variation = system->getVariation();
 	std::string fname     = fileName + SYSTEMTYPE + variation + ".txt";
 
 	log->info(0, "gSystemTextFileStream filename is: ", fname);
 
 	// default dir is "."
-	auto IN = new std::ifstream(fname.c_str());
+	auto IN = std::make_unique<std::ifstream>(fname.c_str());
 
 	if (IN->good()) {
 		log->info(1, "Trying file ", fname);

gemc/gsystem/gsystemFactories/text/systemTextFactory.h

@@ -3,6 +3,10 @@
 // gsystem
 #include <gemc/gsystem/gsystemFactories/systemFactory.h>
 
+// c++
+#include <fstream>
+#include <memory>
+
 // file types
 #define GTEXTGEOMTYPE "__geometry_"
 #define GTEXTMATSTYPE "__materials_"
@@ -76,5 +80,5 @@ class GSystemTextFactory : public GSystemFactory
 	 * - For geometry, failure to locate a file triggers an error unless \c system->getAnnotations() is \c "mats_only".
 	 * - For materials, failure to locate a file is treated as "no materials provided".
 	 */
-	std::ifstream* gSystemTextFileStream(GSystem* system, const std::string& SYSTEMTYPE);
+	std::unique_ptr<std::ifstream> gSystemTextFileStream(GSystem* system, const std::string& SYSTEMTYPE);
 };