sl@0: /*
sl@0: ** 2008 June 18
sl@0: **
sl@0: ** The author disclaims copyright to this source code.  In place of
sl@0: ** a legal notice, here is a blessing:
sl@0: **
sl@0: **    May you do good and not evil.
sl@0: **    May you find forgiveness for yourself and forgive others.
sl@0: **    May you share freely, never taking more than you give.
sl@0: **
sl@0: *************************************************************************
sl@0: **
sl@0: ** This module implements the sqlite3_status() interface and related
sl@0: ** functionality.
sl@0: **
sl@0: ** $Id: status.c,v 1.9 2008/09/02 00:52:52 drh Exp $
sl@0: */
sl@0: #include "sqliteInt.h"
sl@0: 
sl@0: /*
sl@0: ** Variables in which to record status information.
sl@0: */
sl@0: typedef struct sqlite3StatType sqlite3StatType;
sl@0: static SQLITE_WSD struct sqlite3StatType {
sl@0:   int nowValue[9];         /* Current value */
sl@0:   int mxValue[9];          /* Maximum value */
sl@0: } sqlite3Stat = { {0,}, {0,} };
sl@0: 
sl@0: 
sl@0: /* The "wsdStat" macro will resolve to the status information
sl@0: ** state vector.  If writable static data is unsupported on the target,
sl@0: ** we have to locate the state vector at run-time.  In the more common
sl@0: ** case where writable static data is supported, wsdStat can refer directly
sl@0: ** to the "sqlite3Stat" state vector declared above.
sl@0: */
sl@0: #ifdef SQLITE_OMIT_WSD
sl@0: # define wsdStatInit  sqlite3StatType *x = &GLOBAL(sqlite3StatType,sqlite3Stat)
sl@0: # define wsdStat x[0]
sl@0: #else
sl@0: # define wsdStatInit
sl@0: # define wsdStat sqlite3Stat
sl@0: #endif
sl@0: 
sl@0: /*
sl@0: ** Return the current value of a status parameter.
sl@0: */
sl@0: int sqlite3StatusValue(int op){
sl@0:   wsdStatInit;
sl@0:   assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
sl@0:   return wsdStat.nowValue[op];
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Add N to the value of a status record.  It is assumed that the
sl@0: ** caller holds appropriate locks.
sl@0: */
sl@0: void sqlite3StatusAdd(int op, int N){
sl@0:   wsdStatInit;
sl@0:   assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
sl@0:   wsdStat.nowValue[op] += N;
sl@0:   if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
sl@0:     wsdStat.mxValue[op] = wsdStat.nowValue[op];
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Set the value of a status to X.
sl@0: */
sl@0: void sqlite3StatusSet(int op, int X){
sl@0:   wsdStatInit;
sl@0:   assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
sl@0:   wsdStat.nowValue[op] = X;
sl@0:   if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
sl@0:     wsdStat.mxValue[op] = wsdStat.nowValue[op];
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Query status information.
sl@0: **
sl@0: ** This implementation assumes that reading or writing an aligned
sl@0: ** 32-bit integer is an atomic operation.  If that assumption is not true,
sl@0: ** then this routine is not threadsafe.
sl@0: */
sl@0: int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
sl@0:   wsdStatInit;
sl@0:   if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
sl@0:     return SQLITE_MISUSE;
sl@0:   }
sl@0:   *pCurrent = wsdStat.nowValue[op];
sl@0:   *pHighwater = wsdStat.mxValue[op];
sl@0:   if( resetFlag ){
sl@0:     wsdStat.mxValue[op] = wsdStat.nowValue[op];
sl@0:   }
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Query status information for a single database connection
sl@0: */
sl@0: int sqlite3_db_status(
sl@0:   sqlite3 *db,          /* The database connection whose status is desired */
sl@0:   int op,               /* Status verb */
sl@0:   int *pCurrent,        /* Write current value here */
sl@0:   int *pHighwater,      /* Write high-water mark here */
sl@0:   int resetFlag         /* Reset high-water mark if true */
sl@0: ){
sl@0:   switch( op ){
sl@0:     case SQLITE_DBSTATUS_LOOKASIDE_USED: {
sl@0:       *pCurrent = db->lookaside.nOut;
sl@0:       *pHighwater = db->lookaside.mxOut;
sl@0:       if( resetFlag ){
sl@0:         db->lookaside.mxOut = db->lookaside.nOut;
sl@0:       }
sl@0:       break;
sl@0:     }
sl@0:     default: {
sl@0:       return SQLITE_ERROR;
sl@0:     }
sl@0:   }
sl@0:   return SQLITE_OK;
sl@0: }