examples/Base/IPC/Async/AcceptInput1/AcceptInput1.cpp

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Description:  
Asynchronous keyboard processing with messenger program.
A single CKeyMessengerProcessor active object (derived from
class CActiveConsole) which accepts input from keyboard, but does not
print it.
This object contains a CMessageTimer object which it activates if the
user inputs the character "m" and cancelled if the user inputs "c".
*/


#include "CommonFramework.h"

//
// Common literal text
//
_LIT(KTextEsc,"\n");

// panics
enum
        {
        EPanicAlreadyActive=1000,
        };


//
// -----> CTimedMessenger (definition)
//
class CTimedMessenger : public CTimer
        {
public:
          // Construction
        CTimedMessenger();
      // Destruction
        ~CTimedMessenger();

public:
          // Static construction
        static CTimedMessenger* NewLC(const TDesC& aGreeting,
                                          TInt aTicksRequested,
                                                                  TInt aTicksInterval
                                                                 );
        static CTimedMessenger* NewL(const TDesC& aGreeting,
                                         TInt aTicksRequested,
                                                                 TInt aTicksInterval
                                                                );

public:
          // Second phase construction
        void ConstructL(const TDesC& aGreeting,
                            TInt aTicksRequested,
                                        TInt aTicksInterval
                                   );

          // issue request
        void IssueRequest(); 

          // Cancel request
          // Defined as pure virtual by CActive;
          // implementation provided by this class.
        void DoCancel();

          // service completed request.
          // Defined as pure virtual by CActive;
          // implementation provided by this class.
        void RunL();

public:
          // data members defined by this class
        TBufC<20> iGreeting;   // Text of the greeting.
        TInt iTicksRequested;  // Total number of greetings CTimedMessenger
                               // will emit.
        TInt iTicksInterval;   // Number of seconds between each greeting.
        TInt iTicksDone;       // Number of greetings issued so far.
        };


//
// -----> CExampleScheduler (definition)
//
class CExampleScheduler : public CActiveScheduler
        {
public:
        void Error (TInt aError) const;
        };


//
// -----> CActiveConsole (definition)
//
// An abstract class which provides the facility to issue key requests. 
//
class CActiveConsole : public CActive
        {
public:
          // Construction
        CActiveConsole(CConsoleBase* aConsole);
        void ConstructL();

          // Destruction
        ~CActiveConsole();

          // Issue request
        void RequestCharacter();
        
          // Cancel request.
          // Defined as pure virtual by CActive;
          // implementation provided by this class.
        void DoCancel();

          // Service completed request.
          // Defined as pure virtual by CActive;
          // implementation provided by this class,
        void RunL();

          // Called from RunL() - an implementation must be provided
          // by derived classes to handle the completed request
        virtual void ProcessKeyPress(TChar aChar) = 0; 
          
protected:
          // Data members defined by this class
        CConsoleBase* iConsole; // A console for reading from
        };


//
// -----> CWriteKeyProcessor (definition)
//
// This class is derived from CActiveConsole. 
// Request handling: accepts input from the keyboard and outputs it 
// to the console.
//
class CWriteKeyProcessor : public CActiveConsole
        {
public:
          // Construction
        CWriteKeyProcessor(CConsoleBase* aConsole);

public:
          // Static constuction
        static CWriteKeyProcessor *NewLC (CConsoleBase* aConsole);
        static CWriteKeyProcessor *NewL(CConsoleBase* aConsole);

          // Service request
        void ProcessKeyPress(TChar aChar);
        };


//
// -----> CTimedMessenger (implementation)
//
CTimedMessenger::CTimedMessenger()
        : CTimer(CActive::EPriorityStandard)
          // Construct  zero-priority active object
        {};

CTimedMessenger* CTimedMessenger::NewLC(const TDesC& aGreeting,
                                                                                TInt aTicksRequested,
                                                                                TInt aTicksInterval
                                                                           )
        {
        CTimedMessenger* self=new (ELeave) CTimedMessenger;
        CleanupStack::PushL(self);
        self->ConstructL(aGreeting,aTicksRequested,aTicksInterval);
        return self;
        }

CTimedMessenger* CTimedMessenger::NewL(const TDesC& aGreeting,
                                                                   TInt aTicksRequested,
                                                                           TInt aTicksInterval
                                                                          )
        {
        CTimedMessenger* self = NewLC(aGreeting,aTicksRequested,aTicksInterval);
        CleanupStack::Pop();
        return self;
        }

void CTimedMessenger::ConstructL(const TDesC& aGreeting,
                                                                 TInt aTicksRequested,
                                                                 TInt aTicksInterval
                                                                )
        {
          // Base class second-phase construction.
        CTimer::ConstructL();
          // Set members from arguments
        iGreeting       = aGreeting;       // Set greeting text.
        iTicksRequested = aTicksRequested; // Ticks requested
        iTicksInterval  = aTicksInterval;  // Interval between ticks
          // Add active object to active scheduler
        CActiveScheduler::Add(this); 
        }


CTimedMessenger::~CTimedMessenger()
        {
          // Make sure we're cancelled
        Cancel();
        }

void CTimedMessenger::DoCancel()
        {
          // Base class
        CTimer::DoCancel(); 
          // Reset this variable - needed if the object is re-activated later
        iTicksDone = 0;
          // Tell user
        _LIT(KMsgCancelled,"Outstanding Messenger request cancelled\n");
        console->Printf(KMsgCancelled); 
        }

void CTimedMessenger::IssueRequest()
        {
          // There should never be an outstanding request at this point.
        _LIT(KMsgAlreadyActive,"Is already Active");
        __ASSERT_ALWAYS(!IsActive(),User::Panic(KMsgAlreadyActive,EPanicAlreadyActive));
          // Request another wait
        CTimer::After( iTicksInterval*1000000);
        }

void CTimedMessenger::RunL()
        {
          // Handle request completion
          // One more tick done
        iTicksDone++;
          // Print greeting
        _LIT(KFormatString1,"%S \n");
        console->Printf(KFormatString1,&iGreeting);
          // Issue new request, or stop if we have reached the limit
        if (iTicksDone  < iTicksRequested)
                {
                IssueRequest();
                }
        else
                {
                _LIT(KMsgFinished,"Messenger finished \n");
                console->Printf(KMsgFinished);
                  // Reset this variable - needed if the object is re-activated later
                iTicksDone=0;
                  // Can now stop the active scheduler
                CActiveScheduler::Stop();
                }
        }


//
// -----> CExampleScheduler (implementation)
//
void CExampleScheduler::Error(TInt aError) const
        {
        _LIT(KMsgSchedErr,"CExampleScheduler-error");
        User::Panic(KMsgSchedErr,aError);
        }


//
// -----> CActiveConsole (implementation)
//
CActiveConsole::CActiveConsole( CConsoleBase* aConsole) 
        : CActive(CActive::EPriorityUserInput)
          // Construct high-priority active object
        {
        iConsole = aConsole;
        }

void CActiveConsole::ConstructL()
        {
          // Add to active scheduler
        CActiveScheduler::Add(this);
        }

CActiveConsole::~CActiveConsole()
        {
        // Make sure we're cancelled
        Cancel();
        }

void  CActiveConsole::DoCancel()
        {
        iConsole->ReadCancel();
        }

void  CActiveConsole::RunL()
        {
          // Handle completed request
        ProcessKeyPress(TChar(iConsole->KeyCode()));
        }

void CActiveConsole::RequestCharacter()
        {
          // A request is issued to the CConsoleBase to accept a
          // character from the keyboard.
        iConsole->Read(iStatus); 
        SetActive();
        }


//
// -----> CWriteKeyProcessor (implementation)
//
CWriteKeyProcessor::CWriteKeyProcessor(CConsoleBase* aConsole)
        : CActiveConsole(aConsole)
          
        {};

CWriteKeyProcessor* CWriteKeyProcessor::NewLC(CConsoleBase* aConsole)
        {
        CWriteKeyProcessor* self=new (ELeave) CWriteKeyProcessor(aConsole);
        CleanupStack::PushL(self);
        self->ConstructL();
        return self;
        }

CWriteKeyProcessor* CWriteKeyProcessor::NewL(CConsoleBase* aConsole)
        {
        CWriteKeyProcessor* self=NewLC(aConsole);
        CleanupStack::Pop();
        return self;
        }

void CWriteKeyProcessor::ProcessKeyPress(TChar aChar)
        {
          // "Esc" character prints a new line and stops the scheduler
        if (aChar == EKeyEscape)
                {
                iConsole->Printf(KTextEsc);
                CActiveScheduler::Stop();
                return;
                }

          // "Enter" prints a new line character
          // An alphabetic or space is printed as a character;
          // anything else is printed as an integer.
        if (aChar == EKeyEnter)
                iConsole->Printf(KTextEsc);
        else
                {
                _LIT(KFormatString2,"%c");
                _LIT(KFormatString3,"%d");
                if (aChar.IsAlphaDigit()|| aChar.IsSpace())
                        iConsole->Printf(KFormatString2,TUint(aChar));
                else
                        iConsole->Printf(KFormatString3,TUint(aChar));
                }

          // Issue another request 
        RequestCharacter();
        }


//
// -----> CMessageKeyProcessor (definition)
//
// This class is derived from CActiveConsole. 
// Request handling:
//   if key is "m", a message timer request is issued.
//   if key is "c", any outstanding message timer request is cancelled.
//   If key is ESC, the wait loop is terminated.
//
class CMessageKeyProcessor : public CActiveConsole
        {
public:
          // Construction
        CMessageKeyProcessor(CConsoleBase* aConsole, CTimedMessenger* iMessenger);
        void ConstructL();

public:
          // Static construction
        static CMessageKeyProcessor* NewLC(CConsoleBase* aConsole,
                                               CTimedMessenger* iMessenger
                                                                          );
        static CMessageKeyProcessor* NewL(CConsoleBase* aConsole,
                                              CTimedMessenger* iMessenger
                                                                         );

public:
          // service request
        void ProcessKeyPress(TChar aChar);

private:
          // Data members defined by this class
        CTimedMessenger* iMessenger;
        };

//
// -----> CMessageKeyProcessor (implementation)
//
CMessageKeyProcessor::CMessageKeyProcessor(CConsoleBase* aConsole,
                                                                                   CTimedMessenger* aMessenger
                                                                                  )
        : CActiveConsole(aConsole)
          // construct zero-priority active object
        {
        iMessenger = aMessenger;
        } 

CMessageKeyProcessor* CMessageKeyProcessor::NewLC(CConsoleBase* aConsole,
                                                                                                  CTimedMessenger* aMessenger
                                                                                                 )
        {
        CMessageKeyProcessor* self=new (ELeave) CMessageKeyProcessor(aConsole,
                                                                         aMessenger
                                                                                                                                );
        CleanupStack::PushL(self);
        self->ConstructL();
        return self;
        }

CMessageKeyProcessor* CMessageKeyProcessor::NewL(CConsoleBase* aConsole,
                                                                                                 CTimedMessenger* aMessenger
                                                                                                )
        {
        CMessageKeyProcessor* self = NewLC(aConsole, aMessenger);
        CleanupStack::Pop();
        return self;
        }

void CMessageKeyProcessor::ConstructL()
        {
          // Add to active scheduler
        CActiveScheduler::Add(this);
        }

void CMessageKeyProcessor::ProcessKeyPress(TChar aChar)
        {
          // if key is ESC 
          //   cancel any outstanding request
          //   stop the scheduler
        if (aChar == EKeyEscape)
                {
                iMessenger->Cancel();
                CActiveScheduler::Stop();
                return;
                }

          // If key is "m" or "M"
          //   cancel any outstanding request
          //   reset the tick counter
          //   issue a message timer request.
        if (aChar == 'm' || aChar == 'M') 
                {
                _LIT(KMsgStarting,"Starting Messenger....  \n");
                iConsole->Printf(KMsgStarting);
                iMessenger->Cancel();
                iMessenger ->IssueRequest();
                }

      // If key is "c" or "C" 
          //    cancel any outstanding request  
        if (aChar == 'c' || aChar == 'C')
                iMessenger->Cancel();
        
          // Ask for another character.
        RequestCharacter();
        }


//
// Do the example
//
LOCAL_C void doExampleL()
    {
          // Construct and install the active scheduler
        CExampleScheduler*  exampleScheduler = new (ELeave) CExampleScheduler;

          // Push onto the cleanup stack
        CleanupStack::PushL(exampleScheduler);
         
          // Install as the active scheduler
        CActiveScheduler::Install(exampleScheduler);

          // Create a CTimedMessenger active object which will emit
          // 3 messages with an interval of 2 seconds between messages.
        _LIT(KMsgGoodMorning,"Good Morning!");
        CTimedMessenger* messenger = CTimedMessenger::NewLC(KMsgGoodMorning, 3, 2);

          // Create aCMessageKeyProcessor active object.
        _LIT(KMsgTitleA,"A single CKeyMessengerProcessor active object which contains a CMessageTimer.\n");
        console->Printf(KMsgTitleA);
        _LIT(KMsgTitleB,"Press 'm' to activate messenger; Press 'c' to cancel it.\nPress ESC to end.\n\n");
        console->Printf(KMsgTitleB);
        CMessageKeyProcessor* keyProcesser = CMessageKeyProcessor::NewLC(console,
                                                                             messenger
                                                                                                                                         );
          
          // Issue the first request
        keyProcesser->RequestCharacter();
        
          // Main part of the program is a wait loop
        CActiveScheduler::Start();

        // Remove from the cleanup stack and destroy:
        // 1. the CTimedMessenger active object
        // 2. the CMessageKeyProcessor active object.
        // 3. exampleScheduler
        CleanupStack::PopAndDestroy(3); 
        }

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