Android buffer allocator implementation (#1214)

* Implemented basic android buffer allocator for newer wrapped buffer classes to be used instead of the default ReflectionAllocator

jme3-android/src/main/java/com/jme3/system/android/OGLESContext.java

@@ -60,6 +60,8 @@ import com.jme3.renderer.opengl.GLFbo;
 import com.jme3.renderer.opengl.GLRenderer;
 import com.jme3.renderer.opengl.GLTracer;
 import com.jme3.system.*;
+import com.jme3.util.AndroidBufferAllocator;
+import com.jme3.util.BufferAllocatorFactory;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -82,6 +84,14 @@ public class OGLESContext implements JmeContext, GLSurfaceView.Renderer, SoftTex
     protected long minFrameDuration = 0;                   // No FPS cap
     protected long lastUpdateTime = 0;
 
+    static {
+        final String implementation = BufferAllocatorFactory.PROPERTY_BUFFER_ALLOCATOR_IMPLEMENTATION;
+
+        if (System.getProperty(implementation) == null) {
+            System.setProperty(implementation, AndroidBufferAllocator.class.getName());
+        }
+    }
+
     public OGLESContext() {
     }
 

jme3-android/src/main/java/com/jme3/util/AndroidBufferAllocator.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2009-2019 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.jme3.util;
+
+import java.lang.reflect.Field;
+import java.nio.Buffer;
+import java.nio.ByteBuffer;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Jesus Oliver
+ */
+public class AndroidBufferAllocator implements BufferAllocator {
+
+    // We make use of the ReflectionAllocator to remove the inner buffer
+    private static final ReflectionAllocator reflectionAllocator = new ReflectionAllocator();
+
+    private static final String[] wrapperClassNames = {
+            "java.nio.ByteBufferAsFloatBuffer",
+            "java.nio.ByteBufferAsIntBuffer",
+            "java.nio.ByteBufferAsDoubleBuffer",
+            "java.nio.ByteBufferAsShortBuffer",
+            "java.nio.ByteBufferAsLongBuffer",
+            "java.nio.ByteBufferAsCharBuffer",
+    };
+    private static final String[] possibleBufferFieldNames = {"bb", "byteBuffer"};
+
+    // Keep track of ByteBuffer field by the wrapper class
+    private static final Map<Class, Field> fieldIndex = new HashMap<>();
+
+    static {
+        for (String className : wrapperClassNames) {
+            try {
+                Class clazz = Class.forName(className);
+
+                // loop for all possible field names in android
+                for (String fieldName : possibleBufferFieldNames) {
+                    try {
+                        Field field = clazz.getDeclaredField(fieldName);
+                        field.setAccessible(true);
+                        fieldIndex.put(clazz, field);
+                        break;
+                    } catch (NoSuchFieldException e) {
+                    }
+                }
+            } catch (ClassNotFoundException ex) {
+            }
+        }
+    }
+
+    @Override
+    /**
+     * This function search the inner direct buffer of the android specific wrapped buffer classes
+     * and destroys it using the reflection allocator method.
+     *
+     * @param toBeDestroyed The direct buffer that will be "cleaned".
+     *
+     */
+    public void destroyDirectBuffer(Buffer toBeDestroyed) {
+        // If it is a wrapped buffer, get it's inner direct buffer field and destroy it
+        Field field = fieldIndex.get(toBeDestroyed.getClass());
+        if (field != null) {
+            try {
+                ByteBuffer innerBuffer = (ByteBuffer) field.get(toBeDestroyed);
+                if (innerBuffer != null) {
+                    // Destroy it using the reflection method
+                    reflectionAllocator.destroyDirectBuffer(innerBuffer);
+                }
+            } catch (IllegalAccessException ex) {
+            }
+
+        } else {
+            // It is not a wrapped buffer, use default reflection allocator to remove it instead.
+            reflectionAllocator.destroyDirectBuffer(toBeDestroyed);
+        }
+    }
+
+    @Override
+    public ByteBuffer allocate(int size) {
+        return ByteBuffer.allocateDirect(size);
+    }
+}
+