fix : memory 'leak' in query iteration

Author: elebras1

src/main/java/com/github/elebras1/flecs/Query.java

@@ -35,68 +35,76 @@ public interface RunCallback {
 
     public void each(EntityCallback callback) {
         this.checkClosed();
-        var cache = new FlecsContext.ViewCache();
-        ScopedValue.where(FlecsContext.CURRENT_CACHE, cache).run(() -> {
-            MemorySegment iter = flecs_h.ecs_query_iter(this.arena, this.world.nativeHandle(), this.nativeQuery);
-            if (iter == null || iter.address() == 0) {
-                throw new IllegalStateException("ecs_query_iter returned a null iterator");
-            }
+        try (Arena tmpArena = Arena.ofConfined()) {
+            var cache = new FlecsContext.ViewCache();
+            ScopedValue.where(FlecsContext.CURRENT_CACHE, cache).run(() -> {
+                MemorySegment iter = flecs_h.ecs_query_iter(tmpArena, this.world.nativeHandle(), this.nativeQuery);
+                if (iter == null || iter.address() == 0) {
+                    throw new IllegalStateException("ecs_query_iter returned a null iterator");
+                }
 
-            while (flecs_h.ecs_iter_next(iter)) {
-                int count = ecs_iter_t.count(iter);
-                MemorySegment entities = ecs_iter_t.entities(iter);
+                while (flecs_h.ecs_iter_next(iter)) {
+                    int count = ecs_iter_t.count(iter);
+                    MemorySegment entities = ecs_iter_t.entities(iter);
 
-                for (int i = 0; i < count; i++) {
-                    long entityId = entities.getAtIndex(ValueLayout.JAVA_LONG, i);
-                    callback.accept(entityId);
+                    for (int i = 0; i < count; i++) {
+                        long entityId = entities.getAtIndex(ValueLayout.JAVA_LONG, i);
+                        callback.accept(entityId);
+                    }
                 }
-            }
-        });
+            });
+        }
     }
 
     public void iter(IterCallback callback) {
         this.checkClosed();
-        var cache = new FlecsContext.ViewCache();
-        ScopedValue.where(FlecsContext.CURRENT_CACHE, cache).run(() -> {
-            MemorySegment iter = flecs_h.ecs_query_iter(this.arena, this.world.nativeHandle(), this.nativeQuery);
-            if (iter == null || iter.address() == 0) {
-                throw new IllegalStateException("ecs_query_iter returned a null iterator");
-            }
+        try (Arena tmpArena = Arena.ofConfined()) {
+            var cache = new FlecsContext.ViewCache();
+            ScopedValue.where(FlecsContext.CURRENT_CACHE, cache).run(() -> {
+                MemorySegment iter = flecs_h.ecs_query_iter(tmpArena, this.world.nativeHandle(), this.nativeQuery);
+                if (iter == null || iter.address() == 0) {
+                    throw new IllegalStateException("ecs_query_iter returned a null iterator");
+                }
 
-            Iter it = new Iter(iter, this.world);
+                Iter it = new Iter(iter, this.world);
 
-            while (flecs_h.ecs_iter_next(iter)) {
-                it.setNativeIter(iter);
-                callback.accept(it);
-            }
-        });
+                while (flecs_h.ecs_iter_next(iter)) {
+                    it.setNativeIter(iter);
+                    callback.accept(it);
+                }
+            });
+        }
     }
 
     public void run(RunCallback callback) {
         this.checkClosed();
-        var cache = new FlecsContext.ViewCache();
-        ScopedValue.where(FlecsContext.CURRENT_CACHE, cache).run(() -> {
-            MemorySegment iter = flecs_h.ecs_query_iter(this.arena, this.world.nativeHandle(), this.nativeQuery);
+        try (Arena tmpArena = Arena.ofConfined()) {
+            var cache = new FlecsContext.ViewCache();
+            ScopedValue.where(FlecsContext.CURRENT_CACHE, cache).run(() -> {
+                MemorySegment iter = flecs_h.ecs_query_iter(tmpArena, this.world.nativeHandle(), this.nativeQuery);
 
-            if (iter == null || iter.address() == 0) {
-                throw new IllegalStateException("ecs_query_iter returned a null iterator");
-            }
+                if (iter == null || iter.address() == 0) {
+                    throw new IllegalStateException("ecs_query_iter returned a null iterator");
+                }
 
-            Iter it = new Iter(iter, this.world);
-            callback.accept(it);
-        });
+                Iter it = new Iter(iter, this.world);
+                callback.accept(it);
+            });
+        }
     }
 
     public int count() {
         this.checkClosed();
+        try (Arena tmpArena = Arena.ofConfined()) {
+            MemorySegment iter = flecs_h.ecs_query_iter(tmpArena, this.world.nativeHandle(), this.nativeQuery);
 
-        MemorySegment iter = flecs_h.ecs_query_iter(this.arena, this.world.nativeHandle(), this.nativeQuery);
+            int total = 0;
+            while (flecs_h.ecs_iter_next(iter)) {
+                total += ecs_iter_t.count(iter);
+            }
 
-        int total = 0;
-        while (flecs_h.ecs_iter_next(iter)) {
-            total += ecs_iter_t.count(iter);
+            return total;
         }
-        return total;
     }
 
     public LongList entities() {