examples/Base/SmpExample/src/SmpExample.cpp

/*
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  may be used to endorse or promote products derived from this software
  without specific prior written permission.

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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
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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: 
*/

#include <d32dbms.h>  //Used for RDbDatabase class. 
#include "SmpExample.h"
_LIT(KDatabase1, "C:\\DBforSMP1.db");
_LIT(KDatabase2, "C:\\DBforSMP2.db");

CSmpExample::~CSmpExample()
    {
    iReadThread.Close(); //Reader thread closed. 
    iWriteThread1.Close(); //Writer thread closed. 
    iWriteThread2.Close(); //Writer thread closed.
    delete iConsole;
    }

CSmpExample* CSmpExample::NewL()
    {
    CSmpExample* self = new(ELeave)CSmpExample();
    CleanupStack::PushL(self);
    self->ConstructL();
    CleanupStack::Pop(self);
    return self;
    }

void CSmpExample::ConstructL()
    { 
    CreateDatabaseL(KDatabase1);
    CreateDatabaseL(KDatabase2);
    
    _LIT(KTextConsoleTitle, "SmpExample");
    iConsole = Console::NewL(KTextConsoleTitle, TSize(KConsFullScreen, KConsFullScreen));  

    //Creates a reader thread to read the databases.
    _LIT(KReader, "ReaderThread");
    User::LeaveIfError(iReadThread.Create(KReader, ReadThreadFuncL, KDefaultStackSize, KMinHeapSize, 256*KMinHeapSize, this, EOwnerProcess));   

    //Creates a writer thread to write to the DBforSMP1.db database. 
    _LIT(KWriter1, "WriterThread1");
    User::LeaveIfError(iWriteThread1.Create(KWriter1, WriteThread1FuncL, KDefaultStackSize, KMinHeapSize, 256*KMinHeapSize, this, EOwnerProcess));    
    
    //Creates a writer thread to write to the DBforSMP2.db database. 
    _LIT(KWriter2, "WriterThread2");
    User::LeaveIfError(iWriteThread2.Create(KWriter2, WriteThread2FuncL, KDefaultStackSize, KMinHeapSize, 256*KMinHeapSize, this, EOwnerProcess));           


    //Sets priority to the threads. 
    iWriteThread1.SetPriority(EPriorityMuchLess);
    iWriteThread2.SetPriority(EPriorityMore);
    iReadThread.SetPriority(EPriorityNormal);
    }

void CSmpExample::StartThreads()
    {   
    TRequestStatus writerThread1Status; 
    TRequestStatus readerThreadStatus; 
    TRequestStatus writerThread2Status; 
    
    _LIT(KTextPressKey, "\nPress any key to start writing to and reading from the database\n");
    iConsole->Printf(KTextPressKey);
    iConsole->Getch();
  
    //Requests a notification for the ReaderThread to terminate. 
    iReadThread.Logon(readerThreadStatus);
    iReadThread.Resume();
    
    //Requests a notification for the WriterThread1 to terminate. 
    iWriteThread1.Logon(writerThread1Status);   
    iWriteThread1.Resume();
    
    //Requests a notification for the WriterThread2 to terminate. 
    iWriteThread2.Logon(writerThread2Status);   
    iWriteThread2.Resume();
    
    //Control returns to the main thread when the all the threads terminate. 
    User::WaitForRequest(writerThread1Status);
    User::WaitForRequest(readerThreadStatus);
    User::WaitForRequest(writerThread2Status);
    }

void CSmpExample::PrintMessage()
    {
    _LIT(KTextWelcome, "Welcome to the SmpExample.\n");
    _LIT(KTextPurposel1, "There are three threads running in the example: WriterThread1 has the lowest priority,\n");
    _LIT(KTextPurposel2, "ReaderThread has normal priority and WriterThread2 has maximum priority.\n");  
    _LIT(KTextPurposel3, "The two WriterThreads open two different databases and write some integers to them.\n");
    _LIT(KTextPurposel4, "ReaderThread reads the two databases and prints the output to the console.\n");
    
    _LIT(KTextPurposel5, "In a unicore environment, WriterThread1 will be scheduled to run last and would not have\n");
    _LIT(KTextPurposel6, "written to the database when ReaderThread starts reading the databases.\n");
    _LIT(KTextPurposel7, "But in an SMP environment, both the WriterThreads write to their respective databases simultaneously.\n");
    
    iConsole->Printf(KTextWelcome);
    iConsole->Printf(KTextPurposel1);
    iConsole->Printf(KTextPurposel2);
    iConsole->Printf(KTextPurposel3);
    iConsole->Printf(KTextPurposel4);
    iConsole->Printf(KTextPurposel5);
    iConsole->Printf(KTextPurposel6);
    iConsole->Printf(KTextPurposel7);
    }

void CSmpExample::ReadDatabaseL(const TDesC& aDbName, CConsoleBase& console)
    { 
    //Creates a file server session object before any file system manipulation. 
    RFs fsSession;
    CleanupClosePushL(fsSession);
    fsSession.Connect();
    
    //Creates Rdbs object
    RDbs dbs;
    CleanupClosePushL(dbs); 
    dbs.Connect();
    
    //Opens the named database using the RDbs object
    RDbNamedDatabase database;
    CleanupClosePushL(database);
    User::LeaveIfError(database.Open(dbs, aDbName)); 
    
    //Locks the database.
    database.Begin();
    //Prepare an SQL query to read one row of numbers from the database. 
    _LIT(KSQLStatement, "Select Number1, Number2, Number3  from Numbers order by Number1, Number2, Number3");
    
    //Creates a view on the database to read it.
    RDbView view; 
    CleanupClosePushL(view);
    
    User::LeaveIfError(view.Prepare(database, TDbQuery(KSQLStatement, EDbCompareNormal)));
    User::LeaveIfError(view.EvaluateAll());
    
    _LIT(KTextReading, "Reading the database\t %S.\n");
    console.Printf(KTextReading, &aDbName);
    
    //Boolean variable to check whether the database is empty.
    TBool isDbEmpty= EFalse;
    //Iterates through the database till the last row is read. 
    for (view.FirstL(); view.AtRow(); view.NextL())
        {       
        view.GetL();
        TInt number1 = view.ColInt(1);
        TInt number2 = view.ColInt(2);
        TInt number3 = view.ColInt(3);
        //Prepare a row formatter to print numbers in the console. 
        _LIT(KRowFormatter, "Reading  %d \t%d\t%d\n");  
        //Reads the integers from the view and display them in the console.
        console.Printf(KRowFormatter, number1, number2, number3);
        isDbEmpty= ETrue;
        }
    
    if(isDbEmpty== EFalse)
        {
        _LIT(KTextDbEmpty, "Database is empty.\n\n");
        console.Printf(KTextDbEmpty);
        }
    else
        {
        _LIT(KTextAllRead, "All the numbers in the database have been read.\n\n");
        console.Printf(KTextAllRead);
        }            
    
    CleanupStack::PopAndDestroy(&view); 
    CleanupStack::PopAndDestroy(&database);  
    CleanupStack::PopAndDestroy(&dbs);    
    CleanupStack::PopAndDestroy(&fsSession);
    }

void CSmpExample::ReadBothDatabasesL()
    {
    _LIT(KTextConsoleTitle, "ReaderThread");
    CConsoleBase* console= Console::NewL(KTextConsoleTitle, TSize(KConsFullScreen, KConsFullScreen)); 
    CleanupStack::PushL(console);

    //Reads DBforSMP1.db and prints the output to the console. 
    ReadDatabaseL(KDatabase1, *console);
    //Reads DBforSMP2.db and prints the output to the console.
    ReadDatabaseL(KDatabase2, *console);
    
    _LIT(KExit, "Press any key to exit\n");
    console->Printf(KExit);
    console->Getch();
    CleanupStack::PopAndDestroy(console);    
    }

TInt CSmpExample::ReadThreadFuncL(TAny* /*aPtr*/)
    {
    __UHEAP_MARK;
    //Creates cleanup stack.
    CTrapCleanup* cleanup = CTrapCleanup::New();
    if(!cleanup)
        {
        return KErrNoMemory;
        }
     
    TRAPD(error, ReadBothDatabasesL()); 
    if(error != KErrNone)
        {
        _LIT(KUserPanic, "DB Read Failed");  
        User::Panic(KUserPanic, error);
        }
    delete cleanup;
    __UHEAP_MARKEND;
    return KErrNone;
    }

void CSmpExample::WriteDbFuncL(const TDesC& aDbName, TInt aNum)
    {
    //Creates a file server session object before any file system manipulation. 
    RFs fsSession;
    CleanupClosePushL(fsSession);
    fsSession.Connect();


    //Creates Rdbs object   
    RDbs dbs;
    CleanupClosePushL(dbs);
    dbs.Connect();
    
    //Opens the database using the RDbs object
    RDbNamedDatabase database;
    CleanupClosePushL(database);
    User::LeaveIfError(database.Open(dbs, aDbName)); 
    
    //Locks the database.
    database.Begin();
    
    //Creates a view on the database. 
    RDbView view;
    CleanupClosePushL(view);
    _LIT(KSQLStatement, "Select Number1, Number2, Number3 from Numbers order by Number1, Number2, Number3");
    User::LeaveIfError(view.Prepare(database, TDbQuery(KSQLStatement, EDbCompareNormal)));
    User::LeaveIfError(view.EvaluateAll());

    for(int i=0; i<5; i++)
        {
        //Inserts a new row at the end of the database. 
        view.InsertL();
        //Fills three columns with numbers.
        view.SetColL(1, aNum++);
        view.SetColL(2, aNum++);
        view.SetColL(3, aNum++);
        view.PutL();
        }

    CleanupStack::PopAndDestroy(&view);       
    //Commits the database and unlocks it. 
    database.Commit();
    CleanupStack::PopAndDestroy(&database);  
    CleanupStack::PopAndDestroy(&dbs);   
    CleanupStack::PopAndDestroy(&fsSession);
    }


TInt CSmpExample::WriteThread2FuncL(TAny* /*aPtr*/)
    {
    __UHEAP_MARK;
    //Creates cleanup stack.
    CTrapCleanup* cleanup = CTrapCleanup::New();
    if(!cleanup)
        {
        return KErrNoMemory;
        }
    
    //First number to be written to the database. 
    const int KFirstNumforDb2 = 500; 
    TRAPD(err, WriteDbFuncL(KDatabase2, KFirstNumforDb2));
    if(err != KErrNone)
        {
        _LIT(KUserPanic, "DB Write Failed");  
        User::Panic(KUserPanic, err);
        }
    delete cleanup;
    __UHEAP_MARKEND;
    return KErrNone;
    }

TInt CSmpExample::WriteThread1FuncL(TAny* /*aPtr*/)
    {
    __UHEAP_MARK;
    //Creates cleanup stack.
    CTrapCleanup* cleanup = CTrapCleanup::New();
    if(!cleanup)
        {
        return KErrNoMemory;
        }

    //First number to be written to the database. 
    const int KFirstNumforDb1 = 0; 
    TRAPD(err, WriteDbFuncL(KDatabase1, KFirstNumforDb1));
    if(err != KErrNone)
        {
        _LIT(KUserPanic, "DB Write Failed");  
        User::Panic(KUserPanic, err);
        }
    delete cleanup;
    __UHEAP_MARKEND;
    return KErrNone;
    }

void CSmpExample::CreateDatabaseL(const TDesC& aDbName)
    {
    //Creates a file server session object before any file system manipulation. 
    RFs fsSession;
    CleanupClosePushL(fsSession);
    fsSession.Connect();

    //Creates Rdbs object
    RDbs dbs;
    CleanupClosePushL(dbs); 
    dbs.Connect();
    
    //Creates a new database with the name specified in the parameter aDbName, 
    //if database with same name is present, it will be replaced.    
    RDbNamedDatabase database;
    CleanupClosePushL(database);  
    User::LeaveIfError(database.Replace(fsSession, aDbName)); 
    database.Close(); 
    
    //Opens the database using the RDbs object
    User::LeaveIfError(database.Open(dbs, aDbName));       
    //Creates a table definition.
    CDbColSet* columns=CDbColSet::NewLC();

    //Adds three columns each containing Int32 values. 
    _LIT(KCol1, "Number1");
    _LIT(KCol2, "Number2");
    _LIT(KCol3, "Number3");   
    columns->AddL(TDbCol(KCol1, EDbColInt32));
    columns->AddL(TDbCol(KCol2, EDbColInt32));
    columns->AddL(TDbCol(KCol3, EDbColInt32));
 

     //Creates the table, table name is "Numbers" and add the columns to it.
    _LIT(KTable, "Numbers");
    User::LeaveIfError(database.CreateTable(KTable, *columns));
    
    CDbKey* key=CDbKey::NewLC();

     //Add the key columns.
     TDbKeyCol number1(KCol1);
     key->AddL(number1);
     TDbKeyCol number2(KCol2);
     key->AddL(number2);
     TDbKeyCol number3(KCol3);
     key->AddL(number3);
    User::LeaveIfError(database.CreateIndex(KTable, KTable, *key));
    
    //Cleans up the column set.  
    CleanupStack::PopAndDestroy(key);
    CleanupStack::PopAndDestroy(columns);  
    CleanupStack::PopAndDestroy(&database);  
    CleanupStack::PopAndDestroy(&dbs);   
    CleanupStack::PopAndDestroy(&fsSession);
    }

static void MainL()
    {
    CSmpExample* smpExample = CSmpExample::NewL();
    CleanupStack::PushL(smpExample);    
    smpExample->PrintMessage();
    smpExample->StartThreads();
    CleanupStack::PopAndDestroy(smpExample);
    }

extern TInt E32Main()
    {
    //Creates cleanup stack.
    __UHEAP_MARK;
    CTrapCleanup* cleanup = CTrapCleanup::New();
    if(!cleanup)
        {
        return KErrNoMemory;
        }
    //Run application code inside a TRAP harness.
    TRAPD(mainError, MainL());
    if(mainError != KErrNone)
        {
        _LIT(KUserPanic, "Main Failed");  
        User::Panic(KUserPanic, mainError);
        }
    delete cleanup;
    __UHEAP_MARKEND;
    return KErrNone;
    }

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