SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.435 2008/01/01 06:19:02 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

** Return the flag byte at the beginning of the page that the cursor
** is currently pointing to.
*/
int sqlite3BtreeFlags(BtCursor *pCur){
  /* TODO: What about CURSOR_REQUIRESEEK state? Probably need to call
  ** restoreOrClearCursorPosition() here.
  */
  MemPage *pPage = pCur->pPage;


  assert( cursorHoldsMutex(pCur) );
  assert( pPage->pBt==pCur->pBt );
  return pPage ? pPage->aData[pPage->hdrOffset] : 0;
}


/*

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.136 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.

    oldIdx = pParse->nTab++;
  }

  /* Resolve the column names in the WHERE clause.
  */
  assert( pTabList->nSrc==1 );
  iCur = pTabList->a[0].iCursor = pParse->nTab++;



  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  sNC.pSrcList = pTabList;
  if( sqlite3ExprResolveNames(&sNC, pWhere) ){
    goto delete_from_cleanup;
  }

    /* Delete every item whose key was written to the list during the
    ** database scan.  We have to delete items after the scan is complete
    ** because deleting an item can change the scan order.
    */
    end = sqlite3VdbeMakeLabel(v);








    /* This is the beginning of the delete loop when there are
    ** row triggers.
    */
    if( triggers_exist ){
      int mem1 = pParse->nMem++;
      int addr_rowdata;
      u32 mask;
      sqlite3VdbeResolveLabel(v, addr);

      addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, end);
      sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0);


      if( !isView ){
        sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
      }
      sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr);
      sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
      if( old_col_mask ){
        sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
      }else{
        sqlite3VdbeAddOp(v, OP_Null, 0, 0);

      if( !isView ){
        sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0);
      }
    }

    if( !isView ){
      /* Open cursors for the table we are deleting from and all its
      ** indices.  If there are row triggers, this happens inside the
      ** OP_FifoRead loop because the cursor have to all be closed
      ** before the trigger fires.  If there are no row triggers, the
      ** cursors are opened only once on the outside the loop.
      */
      sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);

      /* This is the beginning of the delete loop when there are no
      ** row triggers */
      if( !triggers_exist ){ 
        addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, end);
        sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0);
      }

      /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
      if( IsVirtual(pTab) ){
        pParse->pVirtualLock = pTab;
        sqlite3VdbeOp3(v, OP_VUpdate, 0, 1, (const char*)pTab->pVtab, P3_VTAB);
      }else
#endif
      {
        sqlite3GenerateRowDelete(db, v, pTab, iCur, pParse->nested==0);
      }
    }

    /* If there are row triggers, close all cursors then invoke
    ** the AFTER triggers
    */
    if( triggers_exist ){
      if( !isView ){
        for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
          sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
        }
        sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
      }

      /* Jump back and run the AFTER triggers */
      sqlite3VdbeAddOp(v, OP_Goto, 0, iBeginAfterTrigger);
      sqlite3VdbeJumpHere(v, iEndAfterTrigger);
    }

    /* End of the delete loop */
    sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
    sqlite3VdbeResolveLabel(v, end);

    /* Close the cursors after the loop if there are no row triggers */
    if( !triggers_exist && !IsVirtual(pTab) ){
      for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
        sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
      }
      sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
    }
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.199 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:

  /* Initialize the count of rows to be inserted
  */
  if( db->flags & SQLITE_CountRows ){
    iCntMem = pParse->nMem++;
    sqlite3VdbeAddOp(v, OP_MemInt, 0, iCntMem);
  }

  /* Open tables and indices if there are no row triggers */
  if( !triggers_exist ){
    base = pParse->nTab;
    sqlite3OpenTableAndIndices(pParse, pTab, base, OP_OpenWrite);
  }

  /* If the data source is a temporary table, then we have to create
  ** a loop because there might be multiple rows of data.  If the data
  ** source is a subroutine call from the SELECT statement, then we need

    /* Fire BEFORE or INSTEAD OF triggers */
    if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TRIGGER_BEFORE, pTab, 
        newIdx, -1, onError, endOfLoop, 0, 0) ){
      goto insert_cleanup;
    }
  }

  /* If any triggers exists, the opening of tables and indices is deferred
  ** until now.
  */
  if( triggers_exist && !isView ){
    base = pParse->nTab;
    sqlite3OpenTableAndIndices(pParse, pTab, base, OP_OpenWrite);
  }

  /* Push the record number for the new entry onto the stack.  The
  ** record number is a randomly generate integer created by NewRowid
  ** except when the table has an INTEGER PRIMARY KEY column, in which
  ** case the record number is the same as that column. 
  */
  if( !isView ){
    if( IsVirtual(pTab) ){

  /* Update the count of rows that are inserted
  */
  if( (db->flags & SQLITE_CountRows)!=0 ){
    sqlite3VdbeAddOp(v, OP_MemIncr, 1, iCntMem);
  }

  if( triggers_exist ){
    /* Close all tables opened */
    if( !isView ){
      sqlite3VdbeAddOp(v, OP_Close, base, 0);
      for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
        sqlite3VdbeAddOp(v, OP_Close, idx+base, 0);
      }
    }

    /* Code AFTER triggers */
    if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TRIGGER_AFTER, pTab,
          newIdx, -1, onError, endOfLoop, 0, 0) ){
      goto insert_cleanup;
    }
  }

  /* The bottom of the loop, if the data source is a SELECT statement
  */
  sqlite3VdbeResolveLabel(v, endOfLoop);
  if( useTempTable ){
    sqlite3VdbeAddOp(v, OP_Next, srcTab, iCont);
    sqlite3VdbeResolveLabel(v, iBreak);
    sqlite3VdbeAddOp(v, OP_Close, srcTab, 0);
  }else if( pSelect ){
    sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
    sqlite3VdbeAddOp(v, OP_Return, 0, 0);
    sqlite3VdbeResolveLabel(v, iCleanup);
  }

  if( !triggers_exist && !IsVirtual(pTab) ){
    /* Close all tables opened */
    sqlite3VdbeAddOp(v, OP_Close, base, 0);
    for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
      sqlite3VdbeAddOp(v, OP_Close, idx+base, 0);
    }
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.146 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */

  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* Generate the code for triggers.
  */
  if( triggers_exist ){









    int iGoto = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    addr = sqlite3VdbeMakeLabel(v);
    iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
          newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
      goto update_cleanup;
    }
    iEndBeforeTrigger = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);

  /* Initialize the count of updated rows
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
    memCnt = pParse->nMem++;
    sqlite3VdbeAddOp(v, OP_MemInt, 0, memCnt);
  }

  if( triggers_exist ){
    /* Create pseudo-tables for NEW and OLD




    */
    sqlite3VdbeAddOp(v, OP_OpenPseudo, oldIdx, 0);













    sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol);
    sqlite3VdbeAddOp(v, OP_OpenPseudo, newIdx, 0);
    sqlite3VdbeAddOp(v, OP_SetNumColumns, newIdx, pTab->nCol);




    /* The top of the update loop for when there are triggers.

    */


    sqlite3VdbeResolveLabel(v, addr);



    addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, 0);
    sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0);
    
    if( !isView ){
      /* Open a cursor and make it point to the record that is
      ** being updated.
      */
      sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
    }
    sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr);

    /* Generate the OLD table
    */
    sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
    if( !old_col_mask ){
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);

    }
    sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
    if( !isView ){
      sqlite3TableAffinityStr(v, pTab);
    }
    if( pParse->nErr ) goto update_cleanup;
    sqlite3VdbeAddOp(v, OP_Insert, newIdx, 0);
    if( !isView ){
      sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
    }

    sqlite3VdbeAddOp(v, OP_Goto, 0, iBeginBeforeTrigger);
    sqlite3VdbeJumpHere(v, iEndBeforeTrigger);

    if( !isView ){
      sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0);
    }
  }

  if( !isView && !IsVirtual(pTab) ){
    /* 
    ** Open every index that needs updating.  Note that if any
    ** index could potentially invoke a REPLACE conflict resolution 
    ** action, then we need to open all indices because we might need
    ** to be deleting some records.
    */
    sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); 
    if( onError==OE_Replace ){
      openAll = 1;
    }else{
      openAll = 0;
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        if( pIdx->onError==OE_Replace ){
          openAll = 1;
          break;
        }
      }
    }
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
        sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
        sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum,
                       (char*)pKey, P3_KEYINFO_HANDOFF);
        assert( pParse->nTab>iCur+i+1 );
      }
    }

    /* Loop over every record that needs updating.  We have to load
    ** the old data for each record to be updated because some columns
    ** might not change and we will need to copy the old value.
    ** Also, the old data is needed to delete the old index entries.
    ** So make the cursor point at the old record.
    */
    if( !triggers_exist ){
      addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, 0);
      sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0);
    }
    sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr);
    sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0);

    /* If the record number will change, push the record number as it
    ** will be after the update. (The old record number is currently
    ** on top of the stack.)
    */

    sqlite3VdbeAddOp(v, OP_MemIncr, 1, memCnt);
  }

  /* If there are triggers, close all the cursors after each iteration
  ** through the loop.  The fire the after triggers.
  */
  if( triggers_exist ){
    if( !isView ){
      for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
        if( openAll || aIdxUsed[i] )
          sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
      }
      sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, iBeginAfterTrigger);
    sqlite3VdbeJumpHere(v, iEndAfterTrigger);
  }

  /* Repeat the above with the next record to be updated, until
  ** all record selected by the WHERE clause have been updated.
  */
  sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
  sqlite3VdbeJumpHere(v, addr);

  /* Close all tables if there were no FOR EACH ROW triggers */
  if( !triggers_exist ){
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
      }
    }
    sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
  }else{

    sqlite3VdbeAddOp(v, OP_Close, newIdx, 0);
    sqlite3VdbeAddOp(v, OP_Close, oldIdx, 0);
  }

  /*
  ** Return the number of rows that were changed. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not

      if( zP3==0 || pOp->opcode==OP_Noop ){
        zP3 = zTemp;
        zTemp[0] = 0;
      }
    }
  }
  assert( zP3!=0 );

  if( pOp->zComment && zP3==zTemp && (nP3 = strlen(zP3))<nTemp ){
    sqlite3_snprintf(nTemp-nP3, &zP3[nP3], "%s# %s",
                     nP3>0 ? " " : "", pOp->zComment);
  }

  return zP3;
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**