| // 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.annotation.TargetApi; |
| import android.app.ActivityManager; |
| import android.content.Context; |
| import android.os.Build; |
| import android.os.StrictMode; |
| 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 { |
| // A device reporting strictly more total memory in megabytes cannot be considered 'low-end'. |
| private static final int ANDROID_LOW_MEMORY_DEVICE_THRESHOLD_MB = 512; |
| |
| // Number of kilobytes in a megabyte. |
| private static final int KBS_IN_MB = 1024; |
| |
| private static final String TAG = "SysUtils"; |
| |
| private static Boolean sLowEndDevice; |
| |
| private SysUtils() { } |
| |
| /** |
| * Return the amount of physical memory on this device in kilobytes. |
| * @return Amount of physical memory in kilobytes, or 0 if there was |
| * an error trying to access the information. |
| */ |
| private static int amountOfPhysicalMemoryMB() { |
| // 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$"); |
| // Synchronously reading files in /proc in the UI thread is safe. |
| StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads(); |
| 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 <= KBS_IN_MB) { |
| Log.w(TAG, "Invalid /proc/meminfo total size in kB: " + m.group(1)); |
| break; |
| } |
| |
| return totalMemoryKB / KBS_IN_MB; |
| } |
| |
| } finally { |
| reader.close(); |
| } |
| } finally { |
| fileReader.close(); |
| } |
| } catch (Exception e) { |
| Log.w(TAG, "Cannot get total physical size from /proc/meminfo", e); |
| } finally { |
| StrictMode.setThreadPolicy(oldPolicy); |
| } |
| |
| 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(); |
| } |
| |
| @TargetApi(Build.VERSION_CODES.KITKAT) |
| private static boolean detectLowEndDevice() { |
| assert 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; |
| } |
| // Any pre-KitKat device cannot be considered 'low-end'. |
| if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) { |
| return false; |
| } |
| |
| Context context = ApplicationStatus.getApplicationContext(); |
| if (context != null) { |
| ActivityManager activityManager = (ActivityManager) |
| context.getSystemService(Context.ACTIVITY_SERVICE); |
| if (activityManager.isLowRamDevice()) { |
| return true; |
| } |
| } else { |
| Log.e(TAG, "ApplicationContext is null in ApplicationStatus"); |
| } |
| |
| int ramSizeMB = amountOfPhysicalMemoryMB(); |
| if (ramSizeMB <= 0) { |
| return false; |
| } |
| |
| return ramSizeMB < ANDROID_LOW_MEMORY_DEVICE_THRESHOLD_MB; |
| } |
| } |