| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| package org.chromium.base; |
| |
| import android.os.Build; |
| import android.util.Log; |
| |
| import java.io.BufferedReader; |
| import java.io.FileReader; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| |
| /** |
| * Exposes system related information about the current device. |
| */ |
| public class SysUtils { |
| // Any device that runs this or an older version of the system cannot be considered 'low-end' |
| private static final int ANDROID_LOW_MEMORY_ANDROID_SDK_THRESHOLD = |
| Build.VERSION_CODES.JELLY_BEAN_MR2; |
| |
| // A device reporting strictly more total memory in megabytes cannot be considered 'low-end'. |
| private static final long ANDROID_LOW_MEMORY_DEVICE_THRESHOLD_MB = 512; |
| |
| private static final String TAG = "SysUtils"; |
| |
| private static Boolean sLowEndDevice; |
| |
| private SysUtils() { } |
| |
| /** |
| * Return the amount of physical memory on this device in kilobytes. |
| * Note: the only reason this is public is for testability reason. |
| * @return Amount of physical memory in kilobytes, or 0 if there was |
| * an error trying to access the information. |
| * |
| * Note that this is CalledByNative for testing purpose only. |
| */ |
| @CalledByNative |
| public static int amountOfPhysicalMemoryKB() { |
| // Extract total memory RAM size by parsing /proc/meminfo, note that |
| // this is exactly what the implementation of sysconf(_SC_PHYS_PAGES) |
| // does. However, it can't be called because this method must be |
| // usable before any native code is loaded. |
| |
| // An alternative is to use ActivityManager.getMemoryInfo(), but this |
| // requires a valid ActivityManager handle, which can only come from |
| // a valid Context object, which itself cannot be retrieved |
| // during early startup, where this method is called. And making it |
| // an explicit parameter here makes all call paths _much_ more |
| // complicated. |
| |
| Pattern pattern = Pattern.compile("^MemTotal:\\s+([0-9]+) kB$"); |
| try { |
| FileReader fileReader = new FileReader("/proc/meminfo"); |
| try { |
| BufferedReader reader = new BufferedReader(fileReader); |
| try { |
| String line; |
| for (;;) { |
| line = reader.readLine(); |
| if (line == null) { |
| Log.w(TAG, "/proc/meminfo lacks a MemTotal entry?"); |
| break; |
| } |
| Matcher m = pattern.matcher(line); |
| if (!m.find()) continue; |
| |
| int totalMemoryKB = Integer.parseInt(m.group(1)); |
| // Sanity check. |
| if (totalMemoryKB <= 1024) { |
| Log.w(TAG, "Invalid /proc/meminfo total size in kB: " + m.group(1)); |
| break; |
| } |
| |
| return totalMemoryKB; |
| } |
| |
| } finally { |
| reader.close(); |
| } |
| } finally { |
| fileReader.close(); |
| } |
| } catch (Exception e) { |
| Log.w(TAG, "Cannot get total physical size from /proc/meminfo", e); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * @return Whether or not this device should be considered a low end device. |
| */ |
| @CalledByNative |
| public static boolean isLowEndDevice() { |
| if (sLowEndDevice == null) { |
| sLowEndDevice = detectLowEndDevice(); |
| } |
| return sLowEndDevice.booleanValue(); |
| } |
| |
| /** |
| * @return Whether isLowEndDevice() has ever been called. |
| */ |
| public static boolean isLowEndStateInitialized() { |
| return (sLowEndDevice != null); |
| } |
| |
| private static boolean detectLowEndDevice() { |
| if (CommandLine.isInitialized()) { |
| if (CommandLine.getInstance().hasSwitch(BaseSwitches.ENABLE_LOW_END_DEVICE_MODE)) { |
| return true; |
| } |
| if (CommandLine.getInstance().hasSwitch(BaseSwitches.DISABLE_LOW_END_DEVICE_MODE)) { |
| return false; |
| } |
| } |
| |
| if (Build.VERSION.SDK_INT <= ANDROID_LOW_MEMORY_ANDROID_SDK_THRESHOLD) { |
| return false; |
| } |
| |
| int ramSizeKB = amountOfPhysicalMemoryKB(); |
| return (ramSizeKB > 0 && ramSizeKB / 1024 < ANDROID_LOW_MEMORY_DEVICE_THRESHOLD_MB); |
| } |
| } |