michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.mozglue;
michael@0: 
michael@0: import java.nio.ByteBuffer;
michael@0: 
michael@0: //
michael@0: // We must manually allocate direct buffers in JNI to work around a bug where Honeycomb's
michael@0: // ByteBuffer.allocateDirect() grossly overallocates the direct buffer size.
michael@0: // https://code.google.com/p/android/issues/detail?id=16941
michael@0: //
michael@0: 
michael@0: public final class DirectBufferAllocator {
michael@0:     private DirectBufferAllocator() {}
michael@0: 
michael@0:     public static ByteBuffer allocate(int size) {
michael@0:         if (size <= 0) {
michael@0:             throw new IllegalArgumentException("Invalid size " + size);
michael@0:         }
michael@0: 
michael@0:         ByteBuffer directBuffer = nativeAllocateDirectBuffer(size);
michael@0:         if (directBuffer == null) {
michael@0:             throw new OutOfMemoryError("allocateDirectBuffer() returned null");
michael@0:         } else if (!directBuffer.isDirect()) {
michael@0:             throw new AssertionError("allocateDirectBuffer() did not return a direct buffer");
michael@0:         }
michael@0: 
michael@0:         return directBuffer;
michael@0:     }
michael@0: 
michael@0:     public static ByteBuffer free(ByteBuffer buffer) {
michael@0:         if (buffer == null) {
michael@0:             return null;
michael@0:         }
michael@0: 
michael@0:         if (!buffer.isDirect()) {
michael@0:             throw new IllegalArgumentException("buffer must be direct");
michael@0:         }
michael@0: 
michael@0:         nativeFreeDirectBuffer(buffer);
michael@0:         return null;
michael@0:     }
michael@0: 
michael@0:     // These JNI methods are implemented in mozglue/android/nsGeckoUtils.cpp.
michael@0:     private static native ByteBuffer nativeAllocateDirectBuffer(long size);
michael@0:     private static native void nativeFreeDirectBuffer(ByteBuffer buf);
michael@0: }