KVSQLiteResult.cxx

// @(#)root/sqlite:$Id$
// Author: o.freyermuth <o.f@cern.ch>, 01/06/2013
 
/*************************************************************************
 * Copyright (C) 1995-2013, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include "KVSQLiteResult.h"
#include "TSQLiteRow.h"
 
#include <sqlite3.h>
 
#include <thread>
#include <chrono>
using namespace std::chrono_literals;
 
ClassImp(KVSQLiteResult);
 
 
 
 
KVSQLiteResult::KVSQLiteResult(void* result)
{
   fResult     = (sqlite3_stmt*) result;
 
   // RowCount is -1, as sqlite cannot determine RowCount beforehand:
   fRowCount = -1;
}
 
 
 
 
 
KVSQLiteResult::~KVSQLiteResult()
{
   if (fResult)
      Close();
}
 
 
 
 
 
void KVSQLiteResult::Close(Option_t*)
{
   if (!fResult)
      return;
 
   sqlite3_finalize(fResult);
   fResult     = nullptr;
}
 
 
 
 
 
Bool_t KVSQLiteResult::IsValid(Int_t field)
{
   if (!fResult) {
      Error("IsValid", "result set closed");
      return kFALSE;
   }
   if (field < 0 || field >= GetFieldCount()) {
      Error("IsValid", "field index out of bounds");
      return kFALSE;
   }
   return kTRUE;
}
 
 
 
 
 
Int_t KVSQLiteResult::GetFieldCount()
{
   if (!fResult) {
      Error("GetFieldCount", "result set closed");
      return 0;
   }
   return sqlite3_column_count(fResult);
}
 
 
 
 
 
const char* KVSQLiteResult::GetFieldName(Int_t field)
{
   if (!fResult) {
      Error("GetFieldName", "result set closed");
      return nullptr;
   }
   return sqlite3_column_name(fResult, field);
}
 
 
 
 
 
Int_t KVSQLiteResult::GetRowCount() const
{
   return -1;
}
 
 
 
 
 
TSQLRow* KVSQLiteResult::Next()
{
   if (!fResult) {
      Error("Next", "result set closed");
      return nullptr;
   }
 
   int ret = sqlite3_step(fResult);
   if ((ret != SQLITE_DONE) && (ret != SQLITE_ROW)) {
      if(ret == SQLITE_BUSY)
      {
         // retry the statement 4 times after sleeping
         int i=0;
         do
         {
            ++i;
            Info("Next","DB locked: retry same statement processing in 50ms...(%d)",i);
            std::this_thread::sleep_for(50ms);
            ret = sqlite3_step(fResult);
         }
         while((i<4) && ((ret != SQLITE_DONE) && (ret != SQLITE_ROW)));
         if ((ret != SQLITE_DONE) && (ret != SQLITE_ROW))
         {
            Error("Next", "SQL Error: %d %s", ret, sqlite3_errmsg(sqlite3_db_handle(fResult)));
            return nullptr;
         }
         else
            Info("Next","...statement processing successful!");
         if (ret == SQLITE_DONE) {
            // Finished executing, no other row!
            return nullptr;
         }
         return new TSQLiteRow((void*) fResult, -1);
      }
      Error("Next", "SQL Error: %d %s", ret, sqlite3_errmsg(sqlite3_db_handle(fResult)));
      return nullptr;
   }
   if (ret == SQLITE_DONE) {
      // Finished executing, no other row!
      return nullptr;
   }
   return new TSQLiteRow((void*) fResult, -1);
}