/*
* Copyright (c) 2006 Nokia Corporation and/or its subsidiary(-ies).
* All rights reserved.
* This component and the accompanying materials are made available
* under the terms of "Eclipse Public License v1.0"
* which accompanies this distribution, and is available
* at the URL "http://www.eclipse.org/legal/epl-v10.html".
*
* Initial Contributors:
* Nokia Corporation - initial contribution.
*
* Contributors:
*
* Description: OOM Monitor plug-in interface.
*
*/
#ifndef OOMMONITORPLUGIN_H
#define OOMMONITORPLUGIN_H
#include <e32base.h>
class CMemoryMonitor;
class RFs;
class RWsSession;
/**
* Panic codes with category "OomMonitorPlugin"
*/
enum TOomMonitorPluginPanic
{
/**
* The plugin has been constructed by a thread other than the OOM monitor.
*/
EOomMonitorPluginPanic_PluginConstructedOutsideOomMonitorThread
};
// Message type used to signal an OOM plug-in to free some memory.
const TInt KAppOomMonitor_FreeRam = 0x10282304;
// Message type used to signal an OOM plug-in that there is free memory again.
const TInt KAppOomMonitor_MemoryGood = 0x10282305;
class COomMonitorPlugin : public CBase
{
public:
/**
* Constructor
* Plugins should assume that the system memory is good when
* they are created.
*/
IMPORT_C COomMonitorPlugin();
/**
* Destructor
*/
IMPORT_C ~COomMonitorPlugin();
/**
* 2nd stage constructor
*/
IMPORT_C void ConstructL();
public:
/**
* FreeRam is called when the system RAM level becomes
* low. This plugin is requested to help free some RAM.
*/
virtual void FreeRam() = 0;
/**
* MemoryGood is called when the system RAM level becomes
* good after being low.The plugin may take this opportunity
* to start using RAM again.
* Nb It is assumed that the plugin will not immediately
* cause a large increase in memory use, but that memory may be
* used over time, otherwise the plugin may cause oscillation
* between low and good memory states.
*/
virtual void MemoryGood() = 0;
public:
/**
* Get a handle to the file server.
* @return a connected file server session.
*/
IMPORT_C RFs& FsSession();
/**
* Get a handle to the window server.
* @return a connected window server session.
*/
IMPORT_C RWsSession& WsSession();
protected:
IMPORT_C virtual void ExtensionInterface(TUid aInterfaceId, TAny*& aImplementaion);
private:
CMemoryMonitor* iMemoryMonitor;
};
class COomMonitorPluginV2 : public COomMonitorPlugin
{
public: // From COomMonitorPlugin
/**
* FreeRam is called when the system RAM level becomes
* low. This plugin is requested to help free some RAM.
*
* Note that OomMonitorV2 will not call this version of the function so it does not need to be implemented.
*/
IMPORT_C virtual void FreeRam();
/**
* MemoryGood is called when the system RAM level becomes
* good after being low.The plugin may take this opportunity
* to start using RAM again.
* Nb It is assumed that the plugin will not immediately
* cause a large increase in memory use, but that memory may be
* used over time, otherwise the plugin may cause oscillation
* between low and good memory states.
*/
virtual void MemoryGood() = 0;
public:
/**
* FreeRam is called when the system RAM level becomes
* low. This plugin is requested to help free some RAM.
* Note that it is desirable to delete all memory associated with this plugin if
* not using a disconnected chunk. The reason for this is that by only releasing a small amount
* of the memory you reduce the chances of that memory being at the end of the chunk and therefore
* reduce the likelihood of it being released to the system.
* @param aBytesToFree The minimum number of bytes of free memory that the plugin should try to free.
*/
virtual void FreeRam(TInt aBytesToFree) = 0;
};
/**
* CAppOomMonitorPlugin is a specialised OOM monitor plugin
* that sends messages to applications when the memory state
* changes.
* The target application is specified by the appUid parameter.
* the message will be sent to all running instances of this app.
* The messages are:
* KAppOomMonitor_FreeRam when memory should be released.
* KAppOomMonitor_MemoryGood when memory is good again.
*
* These messages can be picked up in the app UI like this:
* void CMyAppUi::HandleApplicationSpecificEventL(TInt aType, const TWsEvent& aEvent)
* {
* CAknAppUi::HandleApplicationSpecificEventL(aType, aEvent);
* if (aType == KAppOomMonitor_FreeRam)
* {
* // release memory and disable memory use
* }
* else if (aType == KAppOomMonitor_MemoryGood)
* {
* // re-enable memory use
* }
* }
*
* The plugin can be instantiated in an ECom factory function.
* The application does not need to derive from this class.
* For example:
* TAny* CreateAppPlugin()
* {
* return CAppOomMonitorPlugin::NewL(KMyAppUid);
* }
*/
NONSHARABLE_CLASS(CAppOomMonitorPlugin) : public COomMonitorPlugin
{
public:
IMPORT_C static CAppOomMonitorPlugin* NewL(TUid aAppUid);
private:
CAppOomMonitorPlugin(TUid aAppUid);
void FreeRam();
void MemoryGood();
void SendMessageToApp(TInt aMessage);
private:
TUid iAppUid;
};
/**
* Sets the CMemoryMonitor object for this DLL.
* Only for use by CMemoryMonitor.
* @internal
*/
IMPORT_C void SetMemoryMonitorTls(CMemoryMonitor* aMonitor);
#endif // OOMMONITORPLUGIN_H