potentially fix memory leak

Author: JasperGeurtz

src/main/java/bwapi/UnsafeTools.java

@@ -0,0 +1,41 @@
+package bwapi;
+
+import sun.misc.Unsafe;
+
+import java.lang.reflect.Field;
+import java.nio.Buffer;
+
+class UnsafeTools {
+
+    private static Object getOrCrash(final Class<?> className, final Object object, final String fieldName) {
+        try { // get
+            final Field field = className.getDeclaredField(fieldName);
+            final boolean accessible = field.isAccessible();
+            if (!accessible) {
+                field.setAccessible(true);
+            }
+            final Object result = field.get(object);
+            if (!accessible) {
+                field.setAccessible(false);
+            }
+            return result;
+
+        } catch (final Exception e) { // or crash...
+            e.printStackTrace();
+            System.exit(-1);
+            return null;
+        }
+    }
+
+    static Unsafe getUnsafe() {
+        return (Unsafe) getOrCrash(Unsafe.class, null, "theUnsafe");
+    }
+
+    /**
+     * Alternative to `((DirectBuffer) buffer).address())`
+     * (ab)using reflection
+     */
+    static long getAddress(final Buffer buffer) {
+        return (long) getOrCrash(Buffer.class, buffer, "address");
+    }
+}

src/main/java/bwapi/WrappedBuffer.java

@@ -1,6 +1,5 @@
 package bwapi;
 
-import com.sun.jna.Memory;
 import com.sun.jna.Pointer;
 import sun.misc.Unsafe;
 
@@ -29,7 +28,8 @@ class WrappedBuffer {
     }
 
     WrappedBuffer(final int size) {
-        this(new Memory(size), size);
+        buffer = ByteBuffer.allocateDirect(size);
+        address = UnsafeTools.getAddress(buffer);
     }
 
     WrappedBuffer(final Pointer pointer, final int size) {
@@ -90,6 +90,7 @@ void putString(final int offset, final int maxLen, final String string) {
         unsafe.putByte(pos, (byte) 0);
     }
 
+
     ByteBuffer getBuffer() {
         return buffer;
     }

src/test/java/bwapi/UnsafeToolsTest.java

@@ -0,0 +1,31 @@
+package bwapi;
+
+import org.junit.Test;
+import sun.misc.Unsafe;
+
+import java.nio.ByteBuffer;
+
+import static org.junit.Assert.*;
+
+public class UnsafeToolsTest {
+
+    @Test
+    public void testGettingUnsafe() {
+        assertNotNull(UnsafeTools.getUnsafe());
+    }
+
+    @Test
+    public void testDirectByteBuffer() {
+        byte[] bytes = {112, 117, 114, 112, 108, 101, 119, 97, 118, 101};
+        final ByteBuffer buffer = ByteBuffer.allocateDirect(bytes.length);
+        buffer.put(bytes);
+
+        long address = UnsafeTools.getAddress(buffer);
+        assertNotEquals(0, address);
+
+        Unsafe unsafe = UnsafeTools.getUnsafe(); //to obtain memory values via the address
+        for (int i=0; i < bytes.length; i++) {
+            assertEquals(bytes[i], unsafe.getByte(address + i));
+        }
+    }
+}