base/sys_info.cc

   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 #include "base/sys_info.h"
   6
   7 #include "base/base_switches.h"
   8 #include "base/command_line.h"
   9 #include "base/lazy_instance.h"
  10 #include "base/strings/string_number_conversions.h"
  11 #include "base/sys_info_internal.h"
  12 #include "base/time/time.h"
  13
  14 namespace base {
  15
  16 #if !defined(OS_ANDROID)
  17
  18 static const int kLowMemoryDeviceThresholdMB = 512;
  19
  20 bool DetectLowEndDevice() {
  21   CommandLine* command_line = CommandLine::ForCurrentProcess();
  22   int int_value = 0;
  23   if (command_line->HasSwitch(switches::kLowEndDeviceMode)) {
  24     std::string string_value =
  25       command_line->GetSwitchValueASCII(switches::kLowEndDeviceMode);
  26     StringToInt(string_value, &int_value);
  27   }
  28   if (int_value == 1)
  29     return true;
  30   if (int_value != 2)
  31     return false;
  32
  33   int ram_size_mb = SysInfo::AmountOfPhysicalMemoryMB();
  34   return (ram_size_mb > 0 && ram_size_mb < kLowMemoryDeviceThresholdMB);
  35 }
  36
  37 static LazyInstance<
  38   internal::LazySysInfoValue<bool, DetectLowEndDevice> >::Leaky
  39   g_lazy_low_end_device = LAZY_INSTANCE_INITIALIZER;
  40
  41 // static
  42 bool SysInfo::IsLowEndDevice() {
  43   return g_lazy_low_end_device.Get().value();
  44 }
  45 #endif
  46
  47 // static
  48 int64 SysInfo::Uptime() {
  49   // This code relies on an implementation detail of TimeTicks::Now() - that
  50   // its return value happens to coincide with the system uptime value in
  51   // microseconds, on Win/Mac/iOS/Linux/ChromeOS and Android.
  52   int64 uptime_in_microseconds = TimeTicks::Now().ToInternalValue();
  53   return uptime_in_microseconds / 1000;
  54 }
  55
  56 }  // namespace base