examples/Base/MemMan/Cleanup/NewLC/NewLC.cpp

/*
Copyright (c) 2000-2010 Nokia Corporation and/or its subsidiary(-ies). 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 Nokia Corporation 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 BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER 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.

Description:
Example shows use of the NewLC() static function.
NOTE: the structure of this example is different to standard E32 examples  
*/


#include <e32cons.h>

  // All messages written to this
LOCAL_D CConsoleBase* console;
  
  // Flag which determines whether the doSomething() member function
  // of the CExample class should leave when called.
LOCAL_D TBool leaveFlag = ETrue;

  // Parameter for __UHEAP_SETFAIL
  // Allocation guaranteed to fail at this number of allocation attempts;
  // i.e. if set to n, allocation fails on the nth attempt. 
  // NB only used in debug mode
#ifdef _DEBUG
LOCAL_D TInt allocFailNumber = 1;
#endif
  
  // Function prototypes
LOCAL_C void doExampleL();      
LOCAL_C void callExampleL();



//
// -----> CExample (definition)
//
// The class is used by the example code
//
class CExample : public CBase
        {
public :
        static CExample* NewLC(TInt aVal);
        void DoSomethingL();
public :
        TInt iInt;
        };


//
// -----> CExample (implementation)
//
CExample* CExample::NewLC(TInt aVal)
        {
        CExample* self = new (ELeave) CExample;
        CleanupStack::PushL(self);
        self->iInt = aVal;
        return self;
        }


void CExample::DoSomethingL() 
        {
          // Leave if the global flag is set
        if (leaveFlag)
                {
                _LIT(KMsgLeaving,"DoSomethingL leaving.\n");
                console->Printf(KMsgLeaving);
                User::Leave(KErrGeneral);               
                }
        _LIT(KFormat1,"Value of iInt is %d.\n");
        console->Printf(KFormat1,iInt);
        }

//
// Main function called by E32
//
GLDEF_C TInt E32Main()
    {
          // Get cleanup stack
        CTrapCleanup* cleanup=CTrapCleanup::New();

          // Some more initialization, then do the example
        TRAPD(error,callExampleL());
          
          // callExampleL() should never leave.
        _LIT(KMsgPanicEpoc32ex,"EPOC32EX");
        __ASSERT_ALWAYS(!error,User::Panic(KMsgPanicEpoc32ex,error));

          // destroy the cleanup stack
        delete cleanup;
        
          // return
        return 0;
    }


//
//
//
LOCAL_C void callExampleL() 
    {
          // Initialize and call the example code under cleanup stack.
        _LIT(KMsgExampleCode,"Symbian platform Example Code");
        console = Console::NewL(KMsgExampleCode,TSize(KConsFullScreen,KConsFullScreen));
          // Put console onto the cleanup stack.
        CleanupStack::PushL(console);

          // Perform the example function under the protection of a 
          // TRAP harness.
        TRAPD(error,doExampleL());
        _LIT(KMsgOK,"ok");
        _LIT(KFormat2,"failed: leave code = %d");
        if (error)
                console->Printf(KFormat2,error);
        else
                console->Printf(KMsgOK);
          
          // Continue
        _LIT(KMsgPressAnyKey," [press any key]");
        console->Printf(KMsgPressAnyKey);
        console->Getch();

          // Remove the console object from the cleanupstack
          // and destroy it. 
        CleanupStack::PopAndDestroy();
    }


//
// Do the example
//
// Enriched example UsingNewL by using NewLC() instead of NewL().
// The function NewLC() both allocates a CExample object and pushes
// the object onto the cleanup stack
//
void doExampleL()
        {
          // Memory alloc fails on the 'allocFailNumber' attempt. 
        __UHEAP_SETFAIL(RHeap::EDeterministic,allocFailNumber);
          // Allocate and push onto the cleanup stack - leave if 
          // allocation fails.
        CExample* myExample = CExample::NewLC(5);
          // Do something that can leave.
        myExample->DoSomethingL();
          // Pop from the cleanup stack and destroy
        CleanupStack::PopAndDestroy();
        }

---