| 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | package org.chromium.base; |
| 6 | |
| 7 | // The only purpose of this class is to allow sending CPU properties |
| 8 | // from the browser process to sandboxed renderer processes. This is |
| 9 | // needed because sandboxed processes cannot, on ARM, query the kernel |
| 10 | // about the CPU's properties by parsing /proc, so this operation must |
| 11 | // be performed in the browser process, and the result passed to |
| 12 | // renderer ones. |
| 13 | // |
| 14 | // For more context, see http://crbug.com/164154 |
| 15 | // |
| 16 | // Technically, this is a wrapper around the native NDK cpufeatures |
| 17 | // library. The exact CPU features bits are never used in Java so |
| 18 | // there is no point in duplicating their definitions here. |
| 19 | // |
| 20 | @JNINamespace("base::android") |
| 21 | public abstract class CpuFeatures { |
| 22 | /** |
| 23 | * Return the number of CPU Cores on the device. |
| 24 | */ |
| 25 | public static int getCount() { |
| 26 | return nativeGetCoreCount(); |
| 27 | } |
| 28 | |
| 29 | /** |
| 30 | * Return the CPU feature mask. |
| 31 | * This is a 64-bit integer that corresponds to the CPU's features. |
| 32 | * The value comes directly from android_getCpuFeatures(). |
| 33 | */ |
| 34 | public static long getMask() { |
| 35 | return nativeGetCpuFeatures(); |
| 36 | } |
| 37 | |
| 38 | private static native int nativeGetCoreCount(); |
| 39 | private static native long nativeGetCpuFeatures(); |
| 40 | } |