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/*
* Copyright (c) 2013, The Linux Foundation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
* * Neither the name of The Linux Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
package com.android.swe.browser;
import android.app.ActivityManager;
import android.content.Context;
import android.util.Log;
import java.sql.Timestamp;
public class MemoryMonitor {
//This number is used with device memory class to calculate max number
//of active tabs.
private static int sMaxActiveTabs = 0;
private static MemoryMonitor sMemoryMonitor;
private TabControl mTabControl;
private final static String LOGTAG = "MemoryMonitor";
// Should be called only once
public static MemoryMonitor getInstance(Context context,
Controller controller) {
if (sMemoryMonitor == null) {
sMemoryMonitor = new MemoryMonitor(context,controller);
}
return sMemoryMonitor;
}
MemoryMonitor(Context context,Controller controller) {
mTabControl = controller.getTabControl();
sMaxActiveTabs = getMaxActiveTabs(context);
Log.d(LOGTAG,"Max Active Tabs: "+ sMaxActiveTabs);
}
private int getActiveTabs() {
int numNativeActiveTab = 0;
int size = mTabControl.getTabCount();
for (int i = 0; i < size; i++) {
Tab tab = mTabControl.getTab(i);
if (((Tab)tab).isNativeActive()){
numNativeActiveTab++;
}
}
return numNativeActiveTab;
}
/**
* if number of tabs whose native tab is active, is greater
* than MAX_ACTIVE_TABS destroy the nativetab of oldest used Tab
*/
public void destroyLeastRecentlyActiveTab() {
int numActiveTabs = getActiveTabs();
int numActiveTabsToRelease = numActiveTabs - sMaxActiveTabs;
// The most common case will be that we need to delete one
// NativeTab to make room for a new one. So, find the most-stale.
if (numActiveTabsToRelease == 1) {
Tab mostStaleTab = null;
for (Tab t : mTabControl.getTabs()) {
if (t.isNativeActive() && !(t.inForeground())) {
if (mostStaleTab == null){
mostStaleTab = t;
}
else {
if (t.getTimestamp().compareTo(mostStaleTab.
getTimestamp()) < 0) {
mostStaleTab = t;
}
}
}
}
if (mostStaleTab != null) {
mostStaleTab.destroy();
}
} else if (numActiveTabsToRelease > 1) {
// Since there is more than 1 "extra" tab, just release all
// NativeTabs in the background. This would be true when
// tracking was turned on after multiple tabs already exists
for (Tab t : mTabControl.getTabs()) {
if (t.isNativeActive() && !(t.inForeground())) {
t.destroy();
}
}
}
}
/**
* Returns the default max number of active tabs based on device's
* memory class.
*/
static int getMaxActiveTabs(Context context) {
// We use device memory class to decide number of active tabs
// (minimum memory class is 16).
ActivityManager am =(ActivityManager)context.
getSystemService(Context.ACTIVITY_SERVICE);
if (am.getMemoryClass() < 33) {
return 1; // only 1 Tab can be active at a time
}
else {
return 2; // atleast 2 Tabs can be active at a time
}
}
}
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