*/
  zNew = sqlite3NameFromToken(db, pNew);
  if( !zNew ) goto exit_rename_column;
  assert( pNew->n>0 );
  bQuote = sqlite3Isquote(pNew->z[0]);
  sqlite3NestedParse(pParse, 
      "UPDATE \"%w\".%s SET "
      "sql = sqlite_rename_column(sql, %d, %d, %Q, %Q, %Q) "
      "WHERE name NOT LIKE 'sqlite_%%' AND ("

      "   type = 'table' OR (type IN ('index', 'trigger') AND tbl_name = %Q)"
      ")",
      zDb, MASTER_NAME, iCol, bQuote, zNew, pTab->zName, zOld, pTab->zName


  );

  /* Drop and reload the database schema. */
  if( pParse->pVdbe ){
    sqlite3ChangeCookie(pParse, iSchema);
    sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iSchema, 0);
  }
................................................................................
** down into the Walker.
*/
typedef struct RenameCtx RenameCtx;
struct RenameCtx {
  RenameToken *pList;             /* List of tokens to overwrite */
  int nList;                      /* Number of tokens in pList */
  int iCol;                       /* Index of column being renamed */

  const char *zOld;               /* Old column name */
};

/*
** Add a new RenameToken object mapping parse tree element pPtr into
** token *pToken to the Parse object currently under construction.
*/
................................................................................
  RenameToken *p;
  for(p=pToken; p; p=pNext){
    pNext = p->pNext;
    sqlite3DbFree(db, p);
  }
}







static void renameTokenFind(Parse *pParse, RenameCtx *pCtx, void *pPtr){
  RenameToken **pp;
  for(pp=&pParse->pRename; (*pp); pp=&(*pp)->pNext){
    if( (*pp)->p==pPtr ){
      RenameToken *pToken = *pp;
      *pp = pToken->pNext;
      pToken->pNext = pCtx->pList;
      pCtx->pList = pToken;
      pCtx->nList++;
      break;
    }
  }
}















static int renameColumnExprCb(Walker *pWalker, Expr *pExpr){
  RenameCtx *p = pWalker->u.pRename;
  if( p->zOld && pExpr->op==TK_DOT ){
    Expr *pLeft = pExpr->pLeft;
    Expr *pRight = pExpr->pRight;
    assert( pLeft->op==TK_ID && pRight->op==TK_ID );
    if( 0==sqlite3_stricmp(pLeft->u.zToken, "old")
     || 0==sqlite3_stricmp(pLeft->u.zToken, "new")
    ){
      if( 0==sqlite3_stricmp(pRight->u.zToken, p->zOld) ){
        renameTokenFind(pWalker->pParse, p, (void*)pRight);
      }
    }
  }else if( pExpr->op==TK_COLUMN && pExpr->iColumn==p->iCol ){


    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
  }
  return WRC_Continue;
}










static RenameToken *renameColumnTokenNext(RenameCtx *pCtx){
  RenameToken *pBest = pCtx->pList;
  RenameToken *pToken;
  RenameToken **pp;

  for(pToken=pBest->pNext; pToken; pToken=pToken->pNext){
    if( pToken->t.z>pBest->t.z ) pBest = pToken;
................................................................................
  for(pp=&pCtx->pList; *pp!=pBest; pp=&(*pp)->pNext);
  *pp = pBest->pNext;

  return pBest;
}

/*


** sqlite_rename_column(SQL, iCol, bQuote, zNew, zTable, zOld)






















*/
static void renameColumnFunc(
  sqlite3_context *context,
  int NotUsed,
  sqlite3_value **argv
){
  sqlite3 *db = sqlite3_context_db_handle(context);
  RenameCtx sCtx;
  const char *zSql = (const char*)sqlite3_value_text(argv[0]);
  int nSql = sqlite3_value_bytes(argv[0]);


  int bQuote = sqlite3_value_int(argv[2]);
  const char *zNew = (const char*)sqlite3_value_text(argv[3]);
  int nNew = sqlite3_value_bytes(argv[3]);
  const char *zTable = (const char*)sqlite3_value_text(argv[4]);

  const char *zOld = (const char*)sqlite3_value_text(argv[5]);

  int rc;
  char *zErr = 0;
  Parse sParse;
  Walker sWalker;
  Index *pIdx;
  char *zOut = 0;

  char *zQuot = 0;                /* Quoted version of zNew */
  int nQuot = 0;                  /* Length of zQuot in bytes */
  int i;









  memset(&sCtx, 0, sizeof(sCtx));
  sCtx.iCol = sqlite3_value_int(argv[1]);


  memset(&sParse, 0, sizeof(sParse));
  sParse.eParseMode = PARSE_MODE_RENAME_COLUMN;
  sParse.db = db;
  sParse.nQueryLoop = 1;
  rc = sqlite3RunParser(&sParse, zSql, &zErr);
  assert( sParse.pNewTable==0 || sParse.pNewIndex==0 );
................................................................................
    if( zQuot==0 ){
      rc = SQLITE_NOMEM;
    }else{
      nQuot = sqlite3Strlen30(zQuot);
    }
  }

  if( rc!=SQLITE_OK ){
    if( zErr ){
      sqlite3_result_error(context, zErr, -1);
    }else{
      sqlite3_result_error_code(context, rc);
    }
    sqlite3DbFree(db, zErr);
    goto renameColumnFunc_done;
  }

  if( bQuote ){
    zNew = zQuot;
    nNew = nQuot;
  }

#ifdef SQLITE_DEBUG
  assert( sqlite3Strlen30(zSql)==nSql );
  {
    RenameToken *pToken;
    for(pToken=sParse.pRename; pToken; pToken=pToken->pNext){
      assert( pToken->t.z>=zSql && &pToken->t.z[pToken->t.n]<=&zSql[nSql] );
    }
  }
#endif

  /* Find tokens that need to be replaced. */
  memset(&sWalker, 0, sizeof(Walker));
  sWalker.pParse = &sParse;
  sWalker.xExprCallback = renameColumnExprCb;

  sWalker.u.pRename = &sCtx;


  if( sParse.pNewTable ){


















    int bFKOnly = sqlite3_stricmp(zTable, sParse.pNewTable->zName);
    FKey *pFKey;

    if( bFKOnly==0 ){
      renameTokenFind(
          &sParse, &sCtx, (void*)sParse.pNewTable->aCol[sCtx.iCol].zName
      );
      assert( sCtx.iCol>=0 );
      if( sParse.pNewTable->iPKey==sCtx.iCol ){
        sCtx.iCol = -1;

      }
      sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
      for(pIdx=sParse.pNewTable->pIndex; pIdx; pIdx=pIdx->pNext){
        sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
      }
    }

    for(pFKey=sParse.pNewTable->pFKey; pFKey; pFKey=pFKey->pNextFrom){
      for(i=0; i<pFKey->nCol; i++){
        if( bFKOnly==0 && pFKey->aCol[i].iFrom==sCtx.iCol ){
          renameTokenFind(&sParse, &sCtx, (void*)&pFKey->aCol[i]);
        }
        if( 0==sqlite3_stricmp(pFKey->zTo, zTable)
         && 0==sqlite3_stricmp(pFKey->aCol[i].zCol, zOld)
        ){
          renameTokenFind(&sParse, &sCtx, (void*)pFKey->aCol[i].zCol);

        }
      }
    }
  }else if( sParse.pNewIndex ){
    sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
    sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
  }else{
................................................................................
        if( 0==sqlite3_stricmp(zName, zOld) ){
          renameTokenFind(&sParse, &sCtx, (void*)zName);
        }
      }
    }
  }


  assert( nQuot>=nNew );
  zOut = sqlite3DbMallocZero(db, nSql + sCtx.nList*nQuot + 1);
  if( zOut ){
    int nOut = nSql;
    memcpy(zOut, zSql, nSql);
    while( sCtx.pList ){
      int iOff;                   /* Offset of token to replace in zOut */
................................................................................
      }
      memcpy(&zOut[iOff], zReplace, nReplace);
      sqlite3DbFree(db, pBest);
    }

    sqlite3_result_text(context, zOut, -1, SQLITE_TRANSIENT);
    sqlite3DbFree(db, zOut);


  }

renameColumnFunc_done:








  if( sParse.pVdbe ){
    sqlite3VdbeFinalize(sParse.pVdbe);
  }
  sqlite3DeleteTable(db, sParse.pNewTable);
  if( sParse.pNewIndex ) sqlite3FreeIndex(db, sParse.pNewIndex);
  sqlite3DeleteTrigger(db, sParse.pNewTrigger);
  renameTokenFree(db, sParse.pRename);

  */
  zNew = sqlite3NameFromToken(db, pNew);
  if( !zNew ) goto exit_rename_column;
  assert( pNew->n>0 );
  bQuote = sqlite3Isquote(pNew->z[0]);
  sqlite3NestedParse(pParse, 
      "UPDATE \"%w\".%s SET "
      "sql = sqlite_rename_column(sql, %Q, %Q, %d, %Q, %d) "
      "WHERE name NOT LIKE 'sqlite_%%' AND ("
      "       type IN ('table', 'view') "
      "   OR (type IN ('index', 'trigger') AND tbl_name = %Q)"
      ")",
      zDb, MASTER_NAME, 
      zDb, pTab->zName, iCol, zNew, bQuote,
      pTab->zName
  );

  /* Drop and reload the database schema. */
  if( pParse->pVdbe ){
    sqlite3ChangeCookie(pParse, iSchema);
    sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iSchema, 0);
  }
................................................................................
** down into the Walker.
*/
typedef struct RenameCtx RenameCtx;
struct RenameCtx {
  RenameToken *pList;             /* List of tokens to overwrite */
  int nList;                      /* Number of tokens in pList */
  int iCol;                       /* Index of column being renamed */
  Table *pTab;                    /* Table being ALTERed */ 
  const char *zOld;               /* Old column name */
};

/*
** Add a new RenameToken object mapping parse tree element pPtr into
** token *pToken to the Parse object currently under construction.
*/
................................................................................
  RenameToken *p;
  for(p=pToken; p; p=pNext){
    pNext = p->pNext;
    sqlite3DbFree(db, p);
  }
}

/*
** Search the Parse object passed as the first argument for a RenameToken
** object associated with parse tree element pPtr. If found, remove it
** from the Parse object and add it to the list maintained by the
** RenameCtx object passed as the second argument.
*/
static void renameTokenFind(Parse *pParse, struct RenameCtx *pCtx, void *pPtr){
  RenameToken **pp;
  for(pp=&pParse->pRename; (*pp); pp=&(*pp)->pNext){
    if( (*pp)->p==pPtr ){
      RenameToken *pToken = *pp;
      *pp = pToken->pNext;
      pToken->pNext = pCtx->pList;
      pCtx->pList = pToken;
      pCtx->nList++;
      break;
    }
  }
}

static int renameColumnSelectCb(Walker *pWalker, Select *p){
  return WRC_Continue;
}


/*
** This is a Walker expression callback.
**
** For every TK_COLUMN node in the expression tree, search to see
** if the column being references is the column being renamed by an
** ALTER TABLE statement.  If it is, then attach its associated
** RenameToken object to the list of RenameToken objects being
** constructed in RenameCtx object at pWalker->u.pRename.
*/
static int renameColumnExprCb(Walker *pWalker, Expr *pExpr){
  RenameCtx *p = pWalker->u.pRename;
  if( p->zOld && pExpr->op==TK_DOT ){
    Expr *pLeft = pExpr->pLeft;
    Expr *pRight = pExpr->pRight;
    assert( pLeft->op==TK_ID && pRight->op==TK_ID );
    if( 0==sqlite3_stricmp(pLeft->u.zToken, "old")
     || 0==sqlite3_stricmp(pLeft->u.zToken, "new")
    ){
      if( 0==sqlite3_stricmp(pRight->u.zToken, p->zOld) ){
        renameTokenFind(pWalker->pParse, p, (void*)pRight);
      }
    }
  }else if( pExpr->op==TK_COLUMN && pExpr->iColumn==p->iCol 
         && (p->pTab==0 || p->pTab==pExpr->pTab)
  ){
    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
  }
  return WRC_Continue;
}

/*
** The RenameCtx contains a list of tokens that reference a column that
** is being renamed by an ALTER TABLE statement.  Return the "first"
** RenameToken in the RenameCtx and remove that RenameToken from the
** RenameContext.  "First" means the first RenameToken encountered when
** the input SQL from left to right.  Repeated calls to this routine
** return all column name tokens in the order that they are encountered
** in the SQL statement.
*/
static RenameToken *renameColumnTokenNext(RenameCtx *pCtx){
  RenameToken *pBest = pCtx->pList;
  RenameToken *pToken;
  RenameToken **pp;

  for(pToken=pBest->pNext; pToken; pToken=pToken->pNext){
    if( pToken->t.z>pBest->t.z ) pBest = pToken;
................................................................................
  for(pp=&pCtx->pList; *pp!=pBest; pp=&(*pp)->pNext);
  *pp = pBest->pNext;

  return pBest;
}

/*
** SQL function:
**
**     sqlite_rename_column(zSql, iCol, bQuote, zNew, zTable, zOld)
**
**   0. zSql:     SQL statement to rewrite
**   1. Database: Database name (e.g. "main")
**   2. Table:    Table name
**   3. iCol:     Index of column to rename
**   4. zNew:     New column name
**   5. bQuote: True if the new column name should be quoted
**
** Do a column rename operation on the CREATE statement given in zSql.
** The iCol-th column (left-most is 0) of table zTable is renamed from zCol
** into zNew.  The name should be quoted if bQuote is true.
**
** This function is used internally by the ALTER TABLE RENAME COLUMN command.
** Though accessible to application code, it is not intended for use by
** applications.  The existance of this function, and the way it works,
** is subject to change without notice.
**
** If any of the parameters are out-of-bounds, then simply return NULL.
** An out-of-bounds parameter can only occur when the application calls
** this function directly.  The parameters will always be well-formed when
** this routine is invoked by the bytecode for a legitimate ALTER TABLE
** statement.
*/
static void renameColumnFunc(
  sqlite3_context *context,
  int NotUsed,
  sqlite3_value **argv
){
  sqlite3 *db = sqlite3_context_db_handle(context);
  RenameCtx sCtx;
  const char *zSql = (const char*)sqlite3_value_text(argv[0]);
  int nSql = sqlite3_value_bytes(argv[0]);
  const char *zDb = (const char*)sqlite3_value_text(argv[1]);
  const char *zTable = (const char*)sqlite3_value_text(argv[2]);
  int iCol = sqlite3_value_int(argv[3]);
  const char *zNew = (const char*)sqlite3_value_text(argv[4]);
  int nNew = sqlite3_value_bytes(argv[4]);

  int bQuote = sqlite3_value_int(argv[5]);
  const char *zOld;

  int rc;
  char *zErr = 0;
  Parse sParse;
  Walker sWalker;
  Index *pIdx;
  char *zOut = 0;

  char *zQuot = 0;                /* Quoted version of zNew */
  int nQuot = 0;                  /* Length of zQuot in bytes */
  int i;
  Table *pTab;

  if( zSql==0 ) return;
  if( zNew==0 ) return;
  if( zTable==0 ) return;
  if( iCol<0 ) return;
  pTab = sqlite3FindTable(db, zTable, zDb);
  if( pTab==0 || iCol>=pTab->nCol ) return;
  zOld = pTab->aCol[iCol].zName;
  memset(&sCtx, 0, sizeof(sCtx));

  sCtx.iCol = ((iCol==pTab->iPKey) ? -1 : iCol);

  memset(&sParse, 0, sizeof(sParse));
  sParse.eParseMode = PARSE_MODE_RENAME_COLUMN;
  sParse.db = db;
  sParse.nQueryLoop = 1;
  rc = sqlite3RunParser(&sParse, zSql, &zErr);
  assert( sParse.pNewTable==0 || sParse.pNewIndex==0 );
................................................................................
    if( zQuot==0 ){
      rc = SQLITE_NOMEM;
    }else{
      nQuot = sqlite3Strlen30(zQuot);
    }
  }











  if( bQuote ){
    zNew = zQuot;
    nNew = nQuot;
  }

#ifdef SQLITE_DEBUG
  assert( sqlite3Strlen30(zSql)==nSql );
  if( rc==SQLITE_OK ){
    RenameToken *pToken;
    for(pToken=sParse.pRename; pToken; pToken=pToken->pNext){
      assert( pToken->t.z>=zSql && &pToken->t.z[pToken->t.n]<=&zSql[nSql] );
    }
  }
#endif

  /* Find tokens that need to be replaced. */
  memset(&sWalker, 0, sizeof(Walker));
  sWalker.pParse = &sParse;
  sWalker.xExprCallback = renameColumnExprCb;
  sWalker.xSelectCallback = renameColumnSelectCb;
  sWalker.u.pRename = &sCtx;

  if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
  if( sParse.pNewTable ){
    Select *pSelect = sParse.pNewTable->pSelect;
    if( pSelect ){
      sCtx.pTab = pTab;
      sParse.rc = SQLITE_OK;
      sqlite3SelectPrep(&sParse, sParse.pNewTable->pSelect, 0);
      rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
      if( rc==SQLITE_OK ){
        sqlite3WalkSelect(&sWalker, pSelect);
      }else if( rc==SQLITE_ERROR ){
        /* Failed to resolve all symboles in the view. This is not an 
        ** error, but it will not be edited. */
        sqlite3DbFree(db, sParse.zErrMsg);
        sParse.zErrMsg = 0;
        rc = SQLITE_OK;
      }
      if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
    }else{
      /* A regular table */
      int bFKOnly = sqlite3_stricmp(zTable, sParse.pNewTable->zName);
      FKey *pFKey;
      assert( sParse.pNewTable->pSelect==0 );
      if( bFKOnly==0 ){
        renameTokenFind(
            &sParse, &sCtx, (void*)sParse.pNewTable->aCol[iCol].zName
        );


        if( sCtx.iCol<0 ){
          renameTokenFind(&sParse, &sCtx, (void*)&sParse.pNewTable->iPKey);
        }
        sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
        for(pIdx=sParse.pNewTable->pIndex; pIdx; pIdx=pIdx->pNext){
          sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
        }
      }

      for(pFKey=sParse.pNewTable->pFKey; pFKey; pFKey=pFKey->pNextFrom){
        for(i=0; i<pFKey->nCol; i++){
          if( bFKOnly==0 && pFKey->aCol[i].iFrom==sCtx.iCol ){
            renameTokenFind(&sParse, &sCtx, (void*)&pFKey->aCol[i]);
          }
          if( 0==sqlite3_stricmp(pFKey->zTo, zTable)
           && 0==sqlite3_stricmp(pFKey->aCol[i].zCol, zOld)
          ){
            renameTokenFind(&sParse, &sCtx, (void*)pFKey->aCol[i].zCol);
          }
        }
      }
    }
  }else if( sParse.pNewIndex ){
    sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
    sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
  }else{
................................................................................
        if( 0==sqlite3_stricmp(zName, zOld) ){
          renameTokenFind(&sParse, &sCtx, (void*)zName);
        }
      }
    }
  }

  assert( rc==SQLITE_OK );
  assert( nQuot>=nNew );
  zOut = sqlite3DbMallocZero(db, nSql + sCtx.nList*nQuot + 1);
  if( zOut ){
    int nOut = nSql;
    memcpy(zOut, zSql, nSql);
    while( sCtx.pList ){
      int iOff;                   /* Offset of token to replace in zOut */
................................................................................
      }
      memcpy(&zOut[iOff], zReplace, nReplace);
      sqlite3DbFree(db, pBest);
    }

    sqlite3_result_text(context, zOut, -1, SQLITE_TRANSIENT);
    sqlite3DbFree(db, zOut);
  }else{
    rc = SQLITE_NOMEM;
  }

renameColumnFunc_done:
  if( rc!=SQLITE_OK ){
    if( zErr ){
      sqlite3_result_error(context, zErr, -1);
    }else{
      sqlite3_result_error_code(context, rc);
    }
  }

  if( sParse.pVdbe ){
    sqlite3VdbeFinalize(sParse.pVdbe);
  }
  sqlite3DeleteTable(db, sParse.pNewTable);
  if( sParse.pNewIndex ) sqlite3FreeIndex(db, sParse.pNewIndex);
  sqlite3DeleteTrigger(db, sParse.pNewTrigger);
  renameTokenFree(db, sParse.pRename);

    }
  }
  if( nTerm==1
   && pCol
   && sqlite3StrICmp(sqlite3ColumnType(pCol,""), "INTEGER")==0
   && sortOrder!=SQLITE_SO_DESC
  ){



    pTab->iPKey = iCol;
    pTab->keyConf = (u8)onError;
    assert( autoInc==0 || autoInc==1 );
    pTab->tabFlags |= autoInc*TF_Autoincrement;
    if( pList ) pParse->iPkSortOrder = pList->a[0].sortOrder;
  }else if( autoInc ){
#ifndef SQLITE_OMIT_AUTOINCREMENT
................................................................................
  if( sqlite3FixSelect(&sFix, pSelect) ) goto create_view_fail;

  /* Make a copy of the entire SELECT statement that defines the view.
  ** This will force all the Expr.token.z values to be dynamically
  ** allocated rather than point to the input string - which means that
  ** they will persist after the current sqlite3_exec() call returns.
  */




  p->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);

  p->pCheck = sqlite3ExprListDup(db, pCNames, EXPRDUP_REDUCE);
  if( db->mallocFailed ) goto create_view_fail;

  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
  ** the end.
  */
  sEnd = pParse->sLastToken;

    }
  }
  if( nTerm==1
   && pCol
   && sqlite3StrICmp(sqlite3ColumnType(pCol,""), "INTEGER")==0
   && sortOrder!=SQLITE_SO_DESC
  ){
    if( IN_RENAME_COLUMN && pList ){
      sqlite3MoveRenameToken(pParse, &pTab->iPKey, pList->a[0].pExpr);
    }
    pTab->iPKey = iCol;
    pTab->keyConf = (u8)onError;
    assert( autoInc==0 || autoInc==1 );
    pTab->tabFlags |= autoInc*TF_Autoincrement;
    if( pList ) pParse->iPkSortOrder = pList->a[0].sortOrder;
  }else if( autoInc ){
#ifndef SQLITE_OMIT_AUTOINCREMENT
................................................................................
  if( sqlite3FixSelect(&sFix, pSelect) ) goto create_view_fail;

  /* Make a copy of the entire SELECT statement that defines the view.
  ** This will force all the Expr.token.z values to be dynamically
  ** allocated rather than point to the input string - which means that
  ** they will persist after the current sqlite3_exec() call returns.
  */
  if( IN_RENAME_COLUMN ){
    p->pSelect = pSelect;
    pSelect = 0;
  }else{
    p->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
  }
  p->pCheck = sqlite3ExprListDup(db, pCNames, EXPRDUP_REDUCE);
  if( db->mallocFailed ) goto create_view_fail;

  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
  ** the end.
  */
  sEnd = pParse->sLastToken;

  testcase( w.eCode==0 );
  testcase( w.eCode==CKCNSTRNT_COLUMN );
  testcase( w.eCode==CKCNSTRNT_ROWID );
  testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
  return !w.eCode;
}

/*
** An instance of the ConstraintAddr object remembers the byte-code addresses
** for sections of the constraint checks that deal with uniqueness constraints
** on the rowid and on the upsert constraint.
**
** This information is passed into checkReorderConstraintChecks() to insert
** some OP_Goto operations so that the rowid and upsert constraints occur
** in the correct order relative to other constraints.
*/
typedef struct ConstraintAddr ConstraintAddr;
struct ConstraintAddr {
  int ipkTop;          /* Subroutine for rowid constraint check */
  int upsertTop;       /* Label for upsert constraint check subroutine */
  int upsertTop2;      /* Copy of upsertTop not cleared by the call */
  int upsertBtm;       /* upsert constraint returns to this label */
  int ipkBtm;          /* Return opcode rowid constraint check */
};

/*
** Generate any OP_Goto operations needed to cause constraints to be
** run that haven't already been run.
*/
static void reorderConstraintChecks(Vdbe *v, ConstraintAddr *p){
  if( p->upsertTop ){
    testcase( sqlite3VdbeLabelHasBeenResolved(v, p->upsertTop) );
    sqlite3VdbeGoto(v, p->upsertTop);
    VdbeComment((v, "call upsert subroutine"));
    sqlite3VdbeResolveLabel(v, p->upsertBtm);
    p->upsertTop = 0;
  }
  if( p->ipkTop ){
    sqlite3VdbeGoto(v, p->ipkTop);
    VdbeComment((v, "call rowid unique-check subroutine"));
    sqlite3VdbeJumpHere(v, p->ipkBtm);
    p->ipkTop = 0;
  }
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE
** on table pTab.
**
** The regNewData parameter is the first register in a range that contains
** the data to be inserted or the data after the update.  There will be
** pTab->nCol+1 registers in this range.  The first register (the one
................................................................................
  int i;               /* loop counter */
  int ix;              /* Index loop counter */
  int nCol;            /* Number of columns */
  int onError;         /* Conflict resolution strategy */
  int addr1;           /* Address of jump instruction */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
  ConstraintAddr sAddr;/* Address information for constraint reordering */
  Index *pUpIdx = 0;   /* Index to which to apply the upsert */
  u8 isUpdate;         /* True if this is an UPDATE operation */
  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  int upsertBypass = 0;  /* Address of Goto to bypass upsert subroutine */




  isUpdate = regOldData!=0;
  db = pParse->db;
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;
  memset(&sAddr, 0, sizeof(sAddr));
  
  /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
  ** normal rowid tables.  nPkField is the number of key fields in the 
  ** pPk index or 1 for a rowid table.  In other words, nPkField is the
  ** number of fields in the true primary key of the table. */
  if( HasRowid(pTab) ){
    pPk = 0;
................................................................................
    pParse->iSelfTab = 0;
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* UNIQUE and PRIMARY KEY constraints should be handled in the following
  ** order:
  **

  **   (1)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
  **   (2)  OE_Update
  **   (3)  OE_Replace
  **
  ** OE_Fail and OE_Ignore must happen before any changes are made.
  ** OE_Update guarantees that only a single row will change, so it
  ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
  ** could happen in any order, but they are grouped up front for
  ** convenience.





  **
  ** Constraint checking code is generated in this order:
  **   (A)  The rowid constraint
  **   (B)  Unique index constraints that do not have OE_Replace as their
  **        default conflict resolution strategy
  **   (C)  Unique index that do use OE_Replace by default.
  **
................................................................................
    if( pUpsert->pUpsertTarget==0 ){
      /* An ON CONFLICT DO NOTHING clause, without a constraint-target.
      ** Make all unique constraint resolution be OE_Ignore */
      assert( pUpsert->pUpsertSet==0 );
      overrideError = OE_Ignore;
      pUpsert = 0;
    }else if( (pUpIdx = pUpsert->pUpsertIdx)!=0 ){
      /* If the constraint-target is on some column other than
      ** then ROWID, then we might need to move the UPSERT around
      ** so that it occurs in the correct order. */
      sAddr.upsertTop = sAddr.upsertTop2 = sqlite3VdbeMakeLabel(v);
      sAddr.upsertBtm = sqlite3VdbeMakeLabel(v);
    }
  }

  /* If rowid is changing, make sure the new rowid does not previously
  ** exist in the table.
  */
  if( pkChng && pPk==0 ){
................................................................................
    }

    /* If the response to a rowid conflict is REPLACE but the response
    ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
    ** to defer the running of the rowid conflict checking until after
    ** the UNIQUE constraints have run.
    */
    assert( OE_Update>OE_Replace );
    assert( OE_Ignore<OE_Replace );
    assert( OE_Fail<OE_Replace );
    assert( OE_Abort<OE_Replace );
    assert( OE_Rollback<OE_Replace );
    if( onError>=OE_Replace
     && (pUpsert || onError!=overrideError)
     && pTab->pIndex
    ){
      sAddr.ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;

    }

    if( isUpdate ){
      /* pkChng!=0 does not mean that the rowid has changed, only that
      ** it might have changed.  Skip the conflict logic below if the rowid
      ** is unchanged. */
      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
................................................................................
      case OE_Ignore: {
        testcase( onError==OE_Ignore );
        sqlite3VdbeGoto(v, ignoreDest);
        break;
      }
    }
    sqlite3VdbeResolveLabel(v, addrRowidOk);
    if( sAddr.ipkTop ){
      sAddr.ipkBtm = sqlite3VdbeAddOp0(v, OP_Goto);
      sqlite3VdbeJumpHere(v, sAddr.ipkTop-1);
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Compute the revised record entries for indices as we go.
  **
................................................................................
  for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
    int regIdx;          /* Range of registers hold conent for pIdx */
    int regR;            /* Range of registers holding conflicting PK */
    int iThisCur;        /* Cursor for this UNIQUE index */
    int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */

    if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
    if( bAffinityDone==0 ){
      sqlite3TableAffinity(v, pTab, regNewData+1);
      bAffinityDone = 1;
    }
    if( pUpIdx==pIdx ){
      addrUniqueOk = sAddr.upsertBtm;
      upsertBypass = sqlite3VdbeGoto(v, 0);
      VdbeComment((v, "Skip upsert subroutine"));
      sqlite3VdbeResolveLabel(v, sAddr.upsertTop2);

    }else{
      addrUniqueOk = sqlite3VdbeMakeLabel(v);




    }
    VdbeNoopComment((v, "uniqueness check for %s", pIdx->zName));
    iThisCur = iIdxCur+ix;


    /* Skip partial indices for which the WHERE clause is not true */
    if( pIdx->pPartIdxWhere ){
................................................................................
      if( pUpsert->pUpsertSet==0 ){
        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
      }else{
        onError = OE_Update;  /* DO UPDATE */
      }
    }

    /* Invoke subroutines to handle IPK replace and upsert prior to running
    ** the first REPLACE constraint check. */
    if( onError==OE_Replace ){
      testcase( sAddr.ipkTop );
      testcase( sAddr.upsertTop
             && sqlite3VdbeLabelHasBeenResolved(v,sAddr.upsertTop) );
      reorderConstraintChecks(v, &sAddr);
    }

    /* Collision detection may be omitted if all of the following are true:
    **   (1) The conflict resolution algorithm is REPLACE
    **   (2) The table is a WITHOUT ROWID table
    **   (3) There are no secondary indexes on the table
    **   (4) No delete triggers need to be fired if there is a conflict
    **   (5) No FK constraint counters need to be updated if a conflict occurs.
    */ 
................................................................................
            regR, nPkField, 0, OE_Replace,
            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
        seenReplace = 1;
        break;
      }
    }
    if( pUpIdx==pIdx ){

      sqlite3VdbeJumpHere(v, upsertBypass);
    }else{
      sqlite3VdbeResolveLabel(v, addrUniqueOk);
    }
    if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);

  }
  testcase( sAddr.ipkTop!=0 );
  testcase( sAddr.upsertTop
         && sqlite3VdbeLabelHasBeenResolved(v,sAddr.upsertTop) );
  reorderConstraintChecks(v, &sAddr);

  

  *pbMayReplace = seenReplace;
  VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
}

#ifdef SQLITE_ENABLE_NULL_TRIM
/*
** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)

  testcase( w.eCode==0 );
  testcase( w.eCode==CKCNSTRNT_COLUMN );
  testcase( w.eCode==CKCNSTRNT_ROWID );
  testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
  return !w.eCode;
}







































/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE
** on table pTab.
**
** The regNewData parameter is the first register in a range that contains
** the data to be inserted or the data after the update.  There will be
** pTab->nCol+1 registers in this range.  The first register (the one
................................................................................
  int i;               /* loop counter */
  int ix;              /* Index loop counter */
  int nCol;            /* Number of columns */
  int onError;         /* Conflict resolution strategy */
  int addr1;           /* Address of jump instruction */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */

  Index *pUpIdx = 0;   /* Index to which to apply the upsert */
  u8 isUpdate;         /* True if this is an UPDATE operation */
  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  int upsertBypass = 0;  /* Address of Goto to bypass upsert subroutine */
  int upsertJump = 0;    /* Address of Goto that jumps into upsert subroutine */
  int ipkTop = 0;        /* Top of the IPK uniqueness check */
  int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */

  isUpdate = regOldData!=0;
  db = pParse->db;
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;

  
  /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
  ** normal rowid tables.  nPkField is the number of key fields in the 
  ** pPk index or 1 for a rowid table.  In other words, nPkField is the
  ** number of fields in the true primary key of the table. */
  if( HasRowid(pTab) ){
    pPk = 0;
................................................................................
    pParse->iSelfTab = 0;
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* UNIQUE and PRIMARY KEY constraints should be handled in the following
  ** order:
  **
  **   (1)  OE_Update
  **   (2)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore

  **   (3)  OE_Replace
  **
  ** OE_Fail and OE_Ignore must happen before any changes are made.
  ** OE_Update guarantees that only a single row will change, so it
  ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
  ** could happen in any order, but they are grouped up front for
  ** convenience.
  **
  ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
  ** The order of constraints used to have OE_Update as (2) and OE_Abort
  ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
  ** constraint before any others, so it had to be moved.
  **
  ** Constraint checking code is generated in this order:
  **   (A)  The rowid constraint
  **   (B)  Unique index constraints that do not have OE_Replace as their
  **        default conflict resolution strategy
  **   (C)  Unique index that do use OE_Replace by default.
  **
................................................................................
    if( pUpsert->pUpsertTarget==0 ){
      /* An ON CONFLICT DO NOTHING clause, without a constraint-target.
      ** Make all unique constraint resolution be OE_Ignore */
      assert( pUpsert->pUpsertSet==0 );
      overrideError = OE_Ignore;
      pUpsert = 0;
    }else if( (pUpIdx = pUpsert->pUpsertIdx)!=0 ){
      /* If the constraint-target uniqueness check must be run first.
      ** Jump to that uniqueness check now */
      upsertJump = sqlite3VdbeAddOp0(v, OP_Goto);
      VdbeComment((v, "UPSERT constraint goes first"));

    }
  }

  /* If rowid is changing, make sure the new rowid does not previously
  ** exist in the table.
  */
  if( pkChng && pPk==0 ){
................................................................................
    }

    /* If the response to a rowid conflict is REPLACE but the response
    ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
    ** to defer the running of the rowid conflict checking until after
    ** the UNIQUE constraints have run.
    */
    if( onError==OE_Replace      /* IPK rule is REPLACE */





     && onError!=overrideError   /* Rules for other contraints are different */
     && pTab->pIndex             /* There exist other constraints */
    ){
      ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
      VdbeComment((v, "defer IPK REPLACE until last"));
    }

    if( isUpdate ){
      /* pkChng!=0 does not mean that the rowid has changed, only that
      ** it might have changed.  Skip the conflict logic below if the rowid
      ** is unchanged. */
      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
................................................................................
      case OE_Ignore: {
        testcase( onError==OE_Ignore );
        sqlite3VdbeGoto(v, ignoreDest);
        break;
      }
    }
    sqlite3VdbeResolveLabel(v, addrRowidOk);
    if( ipkTop ){
      ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
      sqlite3VdbeJumpHere(v, ipkTop-1);
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Compute the revised record entries for indices as we go.
  **
................................................................................
  for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
    int regIdx;          /* Range of registers hold conent for pIdx */
    int regR;            /* Range of registers holding conflicting PK */
    int iThisCur;        /* Cursor for this UNIQUE index */
    int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */

    if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */




    if( pUpIdx==pIdx ){
      addrUniqueOk = upsertJump+1;
      upsertBypass = sqlite3VdbeGoto(v, 0);
      VdbeComment((v, "Skip upsert subroutine"));

      sqlite3VdbeJumpHere(v, upsertJump);
    }else{
      addrUniqueOk = sqlite3VdbeMakeLabel(v);
    }
    if( bAffinityDone==0 && (pUpIdx==0 || pUpIdx==pIdx) ){
      sqlite3TableAffinity(v, pTab, regNewData+1);
      bAffinityDone = 1;
    }
    VdbeNoopComment((v, "uniqueness check for %s", pIdx->zName));
    iThisCur = iIdxCur+ix;


    /* Skip partial indices for which the WHERE clause is not true */
    if( pIdx->pPartIdxWhere ){
................................................................................
      if( pUpsert->pUpsertSet==0 ){
        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
      }else{
        onError = OE_Update;  /* DO UPDATE */
      }
    }










    /* Collision detection may be omitted if all of the following are true:
    **   (1) The conflict resolution algorithm is REPLACE
    **   (2) The table is a WITHOUT ROWID table
    **   (3) There are no secondary indexes on the table
    **   (4) No delete triggers need to be fired if there is a conflict
    **   (5) No FK constraint counters need to be updated if a conflict occurs.
    */ 
................................................................................
            regR, nPkField, 0, OE_Replace,
            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
        seenReplace = 1;
        break;
      }
    }
    if( pUpIdx==pIdx ){
      sqlite3VdbeGoto(v, upsertJump+1);
      sqlite3VdbeJumpHere(v, upsertBypass);
    }else{
      sqlite3VdbeResolveLabel(v, addrUniqueOk);
    }
    if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
  }

  /* If the IPK constraint is a REPLACE, run it last */
  if( ipkTop ){
    sqlite3VdbeGoto(v, ipkTop+1);
    VdbeComment((v, "Do IPK REPLACE"));
    sqlite3VdbeJumpHere(v, ipkBottom);
  }

  *pbMayReplace = seenReplace;
  VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
}

#ifdef SQLITE_ENABLE_NULL_TRIM
/*
** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)

** Function unixMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
**   unixEnterMutex()
**     assert( unixMutexHeld() );
**   unixEnterLeave()











*/
static sqlite3_mutex *unixBigLock = 0;
static void unixEnterMutex(void){

  sqlite3_mutex_enter(unixBigLock);
}
static void unixLeaveMutex(void){

  sqlite3_mutex_leave(unixBigLock);
}
#ifdef SQLITE_DEBUG
static int unixMutexHeld(void) {
  return sqlite3_mutex_held(unixBigLock);
}
#endif
................................................................................
**
** A single inode can have multiple file descriptors, so each unixFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of unixFile pointing to it.
**
** Mutex rules:
**
**  (1) The pLockMutex mutex must be held in order to read or write
**      any of the locking fields:
**          nShared, nLock, eFileLock, or bProcessLock
**
**  (2) When nRef>0, then the following fields are unchanging and can
**      be read (but not written) without holding any mutex:
**          fileId, pLockMutex
**
**  (3) With the exceptions above, all the fields may only be read
**      or written while holding the global unixBigLock mutex.




*/
struct unixInodeInfo {
  struct unixFileId fileId;       /* The lookup key */
  sqlite3_mutex *pLockMutex;      /* Hold this mutex for... */
  int nShared;                      /* Number of SHARED locks held */
  int nLock;                        /* Number of outstanding file locks */
  unsigned char eFileLock;          /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  unsigned char bProcessLock;       /* An exclusive process lock is held */

  int nRef;                       /* Number of pointers to this structure */
  unixShmNode *pShmNode;          /* Shared memory associated with this inode */
  UnixUnusedFd *pUnused;          /* Unused file descriptors to close */
  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
  unixInodeInfo *pPrev;           /*    .... doubly linked */
#if SQLITE_ENABLE_LOCKING_STYLE
  unsigned long long sharedByte;  /* for AFP simulated shared lock */
#endif
#if OS_VXWORKS
  sem_t *pSem;                    /* Named POSIX semaphore */
................................................................................
#endif
};

/*
** A lists of all unixInodeInfo objects.
*/
static unixInodeInfo *inodeList = 0;  /* All unixInodeInfo objects */
static unsigned int nUnusedFd = 0;    /* Total unused file descriptors */
















/*
**
** This function - unixLogErrorAtLine(), is only ever called via the macro
** unixLogError().
**
** It is invoked after an error occurs in an OS function and errno has been
................................................................................
/*
** Close all file descriptors accumuated in the unixInodeInfo->pUnused list.
*/ 
static void closePendingFds(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p;
  UnixUnusedFd *pNext;

  for(p=pInode->pUnused; p; p=pNext){
    pNext = p->pNext;
    robust_close(pFile, p->fd, __LINE__);
    sqlite3_free(p);
    nUnusedFd--;
  }
  pInode->pUnused = 0;
}

/*
** Release a unixInodeInfo structure previously allocated by findInodeInfo().
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
*/
static void releaseInodeInfo(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  assert( unixMutexHeld() );

  if( ALWAYS(pInode) ){
    pInode->nRef--;
    if( pInode->nRef==0 ){
      assert( pInode->pShmNode==0 );

      closePendingFds(pFile);

      if( pInode->pPrev ){
        assert( pInode->pPrev->pNext==pInode );
        pInode->pPrev->pNext = pInode->pNext;
      }else{
        assert( inodeList==pInode );
        inodeList = pInode->pNext;
      }
................................................................................
        assert( pInode->pNext->pPrev==pInode );
        pInode->pNext->pPrev = pInode->pPrev;
      }
      sqlite3_mutex_free(pInode->pLockMutex);
      sqlite3_free(pInode);
    }
  }
  assert( inodeList!=0 || nUnusedFd==0 );
}

/*
** Given a file descriptor, locate the unixInodeInfo object that
** describes that file descriptor.  Create a new one if necessary.  The
** return value might be uninitialized if an error occurs.
**
................................................................................
  memset(&fileId, 0, sizeof(fileId));
  fileId.dev = statbuf.st_dev;
#if OS_VXWORKS
  fileId.pId = pFile->pId;
#else
  fileId.ino = (u64)statbuf.st_ino;
#endif
  assert( inodeList!=0 || nUnusedFd==0 );
  pInode = inodeList;
  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
    pInode = pInode->pNext;
  }
  if( pInode==0 ){
    pInode = sqlite3_malloc64( sizeof(*pInode) );
    if( pInode==0 ){
................................................................................
/*
** Add the file descriptor used by file handle pFile to the corresponding
** pUnused list.
*/
static void setPendingFd(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p = pFile->pPreallocatedUnused;

  p->pNext = pInode->pUnused;
  pInode->pUnused = p;
  pFile->h = -1;
  pFile->pPreallocatedUnused = 0;
  nUnusedFd++;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
................................................................................

    /* Decrement the count of locks against this same file.  When the
    ** count reaches zero, close any other file descriptors whose close
    ** was deferred because of outstanding locks.
    */
    pInode->nLock--;
    assert( pInode->nLock>=0 );
    if( pInode->nLock==0 ){
      closePendingFds(pFile);
    }
  }

end_unlock:
  sqlite3_mutex_leave(pInode->pLockMutex);

  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;

  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
................................................................................

/*
** Close a file.
*/
static int unixClose(sqlite3_file *id){
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile *)id;



  verifyDbFile(pFile);
  unixUnlock(id, NO_LOCK);

  unixEnterMutex();

  /* unixFile.pInode is always valid here. Otherwise, a different close
  ** routine (e.g. nolockClose()) would be called instead.
  */
  assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 );

  if( ALWAYS(pFile->pInode) && pFile->pInode->nLock ){
    /* If there are outstanding locks, do not actually close the file just
    ** yet because that would clear those locks.  Instead, add the file
    ** descriptor to pInode->pUnused list.  It will be automatically closed 
    ** when the last lock is cleared.
    */
    setPendingFd(pFile);
  }

  releaseInodeInfo(pFile);
  rc = closeUnixFile(id);
  unixLeaveMutex();
  return rc;
}

/************** End of the posix advisory lock implementation *****************
................................................................................
 ** Close a file.
 */
static int semXClose(sqlite3_file *id) {
  if( id ){
    unixFile *pFile = (unixFile*)id;
    semXUnlock(id, NO_LOCK);
    assert( pFile );

    unixEnterMutex();
    releaseInodeInfo(pFile);
    unixLeaveMutex();
    closeUnixFile(id);
  }
  return SQLITE_OK;
}
................................................................................
        pInode->eFileLock = NO_LOCK;
        pFile->eFileLock = NO_LOCK;
      }
    }
    if( rc==SQLITE_OK ){
      pInode->nLock--;
      assert( pInode->nLock>=0 );
      if( pInode->nLock==0 ){
        closePendingFds(pFile);
      }
    }
  }
  
  sqlite3_mutex_leave(pInode->pLockMutex);

  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;

  return rc;
}

/*
** Close a file & cleanup AFP specific locking context 
*/
static int afpClose(sqlite3_file *id) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  assert( id!=0 );
  afpUnlock(id, NO_LOCK);

  unixEnterMutex();



  if( pFile->pInode && pFile->pInode->nLock ){
    /* If there are outstanding locks, do not actually close the file just
    ** yet because that would clear those locks.  Instead, add the file
    ** descriptor to pInode->aPending.  It will be automatically closed when
    ** the last lock is cleared.
    */
    setPendingFd(pFile);


  }
  releaseInodeInfo(pFile);
  sqlite3_free(pFile->lockingContext);
  rc = closeUnixFile(id);
  unixLeaveMutex();
  return rc;
}
................................................................................
  if( p==0 ) return SQLITE_NOMEM_BKPT;
  memset(p, 0, sizeof(*p));
  assert( pDbFd->pShm==0 );

  /* Check to see if a unixShmNode object already exists. Reuse an existing
  ** one if present. Create a new one if necessary.
  */

  unixEnterMutex();
  pInode = pDbFd->pInode;
  pShmNode = pInode->pShmNode;
  if( pShmNode==0 ){
    struct stat sStat;                 /* fstat() info for database file */
#ifndef SQLITE_SHM_DIRECTORY
    const char *zBasePath = pDbFd->zPath;
................................................................................
** any load or store begun after the barrier.
*/
static void unixShmBarrier(
  sqlite3_file *fd                /* Database file holding the shared memory */
){
  UNUSED_PARAMETER(fd);
  sqlite3MemoryBarrier();         /* compiler-defined memory barrier */

  unixEnterMutex();               /* Also mutex, for redundancy */
  unixLeaveMutex();
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.
................................................................................
  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  sqlite3_mutex_leave(pShmNode->mutex);

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too */

  unixEnterMutex();
  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    if( deleteFlag && pShmNode->h>=0 ){
      osUnlink(pShmNode->zFilename);
    }
................................................................................
  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock,    /* xCheckReservedLock method */
  unixShmMap                /* xShmMap method */
)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */
  3,                        /* shared memory is disabled */
  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock,  /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
IOMETHODS(
................................................................................
  ** almost certain that an open() call on the same path will also fail.
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a reusable file descriptor are not dire.  */
  if( nUnusedFd>0 && 0==osStat(zPath, &sStat) ){
    unixInodeInfo *pInode;

    pInode = inodeList;
    while( pInode && (pInode->fileId.dev!=sStat.st_dev
                     || pInode->fileId.ino!=(u64)sStat.st_ino) ){
       pInode = pInode->pNext;
    }
    if( pInode ){
      UnixUnusedFd **pp;


      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
      pUnused = *pp;
      if( pUnused ){
        nUnusedFd--;
        *pp = pUnused->pNext;
      }

    }
  }
  unixLeaveMutex();
#endif    /* if !OS_VXWORKS */
  return pUnused;
}

** Function unixMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
**   unixEnterMutex()
**     assert( unixMutexHeld() );
**   unixEnterLeave()
**
** To prevent deadlock, the global unixBigLock must must be acquired
** before the unixInodeInfo.pLockMutex mutex, if both are held.  It is
** OK to get the pLockMutex without holding unixBigLock first, but if
** that happens, the unixBigLock mutex must not be acquired until after
** pLockMutex is released.
**
**      OK:     enter(unixBigLock),  enter(pLockInfo)
**      OK:     enter(unixBigLock)
**      OK:     enter(pLockInfo)
**   ERROR:     enter(pLockInfo), enter(unixBigLock)
*/
static sqlite3_mutex *unixBigLock = 0;
static void unixEnterMutex(void){
  assert( sqlite3_mutex_notheld(unixBigLock) );  /* Not a recursive mutex */
  sqlite3_mutex_enter(unixBigLock);
}
static void unixLeaveMutex(void){
  assert( sqlite3_mutex_held(unixBigLock) );
  sqlite3_mutex_leave(unixBigLock);
}
#ifdef SQLITE_DEBUG
static int unixMutexHeld(void) {
  return sqlite3_mutex_held(unixBigLock);
}
#endif
................................................................................
**
** A single inode can have multiple file descriptors, so each unixFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of unixFile pointing to it.
**
** Mutex rules:
**
**  (1) Only the pLockMutex mutex must be held in order to read or write
**      any of the locking fields:
**          nShared, nLock, eFileLock, bProcessLock, pUnused
**
**  (2) When nRef>0, then the following fields are unchanging and can
**      be read (but not written) without holding any mutex:
**          fileId, pLockMutex
**
**  (3) With the exceptions above, all the fields may only be read
**      or written while holding the global unixBigLock mutex.
**
** Deadlock prevention:  The global unixBigLock mutex may not
** be acquired while holding the pLockMutex mutex.  If both unixBigLock
** and pLockMutex are needed, then unixBigLock must be acquired first.
*/
struct unixInodeInfo {
  struct unixFileId fileId;       /* The lookup key */
  sqlite3_mutex *pLockMutex;      /* Hold this mutex for... */
  int nShared;                      /* Number of SHARED locks held */
  int nLock;                        /* Number of outstanding file locks */
  unsigned char eFileLock;          /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  unsigned char bProcessLock;       /* An exclusive process lock is held */
  UnixUnusedFd *pUnused;            /* Unused file descriptors to close */
  int nRef;                       /* Number of pointers to this structure */
  unixShmNode *pShmNode;          /* Shared memory associated with this inode */

  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
  unixInodeInfo *pPrev;           /*    .... doubly linked */
#if SQLITE_ENABLE_LOCKING_STYLE
  unsigned long long sharedByte;  /* for AFP simulated shared lock */
#endif
#if OS_VXWORKS
  sem_t *pSem;                    /* Named POSIX semaphore */
................................................................................
#endif
};

/*
** A lists of all unixInodeInfo objects.
*/
static unixInodeInfo *inodeList = 0;  /* All unixInodeInfo objects */


#ifdef SQLITE_DEBUG
/*
** True if the inode mutex is held, or not.  Used only within assert()
** to help verify correct mutex usage.
*/
int unixFileMutexHeld(unixFile *pFile){
  assert( pFile->pInode );
  return sqlite3_mutex_held(pFile->pInode->pLockMutex);
}
int unixFileMutexNotheld(unixFile *pFile){
  assert( pFile->pInode );
  return sqlite3_mutex_notheld(pFile->pInode->pLockMutex);
}
#endif

/*
**
** This function - unixLogErrorAtLine(), is only ever called via the macro
** unixLogError().
**
** It is invoked after an error occurs in an OS function and errno has been
................................................................................
/*
** Close all file descriptors accumuated in the unixInodeInfo->pUnused list.
*/ 
static void closePendingFds(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p;
  UnixUnusedFd *pNext;
  assert( unixFileMutexHeld(pFile) );
  for(p=pInode->pUnused; p; p=pNext){
    pNext = p->pNext;
    robust_close(pFile, p->fd, __LINE__);
    sqlite3_free(p);

  }
  pInode->pUnused = 0;
}

/*
** Release a unixInodeInfo structure previously allocated by findInodeInfo().
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
*/
static void releaseInodeInfo(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  assert( unixMutexHeld() );
  assert( unixFileMutexNotheld(pFile) );
  if( ALWAYS(pInode) ){
    pInode->nRef--;
    if( pInode->nRef==0 ){
      assert( pInode->pShmNode==0 );
      sqlite3_mutex_enter(pInode->pLockMutex);
      closePendingFds(pFile);
      sqlite3_mutex_leave(pInode->pLockMutex);
      if( pInode->pPrev ){
        assert( pInode->pPrev->pNext==pInode );
        pInode->pPrev->pNext = pInode->pNext;
      }else{
        assert( inodeList==pInode );
        inodeList = pInode->pNext;
      }
................................................................................
        assert( pInode->pNext->pPrev==pInode );
        pInode->pNext->pPrev = pInode->pPrev;
      }
      sqlite3_mutex_free(pInode->pLockMutex);
      sqlite3_free(pInode);
    }
  }

}

/*
** Given a file descriptor, locate the unixInodeInfo object that
** describes that file descriptor.  Create a new one if necessary.  The
** return value might be uninitialized if an error occurs.
**
................................................................................
  memset(&fileId, 0, sizeof(fileId));
  fileId.dev = statbuf.st_dev;
#if OS_VXWORKS
  fileId.pId = pFile->pId;
#else
  fileId.ino = (u64)statbuf.st_ino;
#endif

  pInode = inodeList;
  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
    pInode = pInode->pNext;
  }
  if( pInode==0 ){
    pInode = sqlite3_malloc64( sizeof(*pInode) );
    if( pInode==0 ){
................................................................................
/*
** Add the file descriptor used by file handle pFile to the corresponding
** pUnused list.
*/
static void setPendingFd(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p = pFile->pPreallocatedUnused;
  assert( unixFileMutexHeld(pFile) );
  p->pNext = pInode->pUnused;
  pInode->pUnused = p;
  pFile->h = -1;
  pFile->pPreallocatedUnused = 0;

}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
................................................................................

    /* Decrement the count of locks against this same file.  When the
    ** count reaches zero, close any other file descriptors whose close
    ** was deferred because of outstanding locks.
    */
    pInode->nLock--;
    assert( pInode->nLock>=0 );

    if( pInode->nLock==0 ) closePendingFds(pFile);

  }

end_unlock:
  sqlite3_mutex_leave(pInode->pLockMutex);
  if( rc==SQLITE_OK ){
    pFile->eFileLock = eFileLock;
  }
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
................................................................................

/*
** Close a file.
*/
static int unixClose(sqlite3_file *id){
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile *)id;
  unixInodeInfo *pInode = pFile->pInode;

  assert( pInode!=0 );
  verifyDbFile(pFile);
  unixUnlock(id, NO_LOCK);
  assert( unixFileMutexNotheld(pFile) );
  unixEnterMutex();

  /* unixFile.pInode is always valid here. Otherwise, a different close
  ** routine (e.g. nolockClose()) would be called instead.
  */
  assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 );
  sqlite3_mutex_enter(pInode->pLockMutex);
  if( pFile->pInode->nLock ){
    /* If there are outstanding locks, do not actually close the file just
    ** yet because that would clear those locks.  Instead, add the file
    ** descriptor to pInode->pUnused list.  It will be automatically closed 
    ** when the last lock is cleared.
    */
    setPendingFd(pFile);
  }
  sqlite3_mutex_leave(pInode->pLockMutex);
  releaseInodeInfo(pFile);
  rc = closeUnixFile(id);
  unixLeaveMutex();
  return rc;
}

/************** End of the posix advisory lock implementation *****************
................................................................................
 ** Close a file.
 */
static int semXClose(sqlite3_file *id) {
  if( id ){
    unixFile *pFile = (unixFile*)id;
    semXUnlock(id, NO_LOCK);
    assert( pFile );
    assert( unixFileMutexNotheld(pFile) );
    unixEnterMutex();
    releaseInodeInfo(pFile);
    unixLeaveMutex();
    closeUnixFile(id);
  }
  return SQLITE_OK;
}
................................................................................
        pInode->eFileLock = NO_LOCK;
        pFile->eFileLock = NO_LOCK;
      }
    }
    if( rc==SQLITE_OK ){
      pInode->nLock--;
      assert( pInode->nLock>=0 );

      if( pInode->nLock==0 ) closePendingFds(pFile);

    }
  }
  
  sqlite3_mutex_leave(pInode->pLockMutex);
  if( rc==SQLITE_OK ){
    pFile->eFileLock = eFileLock;
  }
  return rc;
}

/*
** Close a file & cleanup AFP specific locking context 
*/
static int afpClose(sqlite3_file *id) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  assert( id!=0 );
  afpUnlock(id, NO_LOCK);
  assert( unixFileMutexNotheld(pFile) );
  unixEnterMutex();
  if( pFile->pInode ){
    unixInodeInfo *pInode = pFile->pInode;
    sqlite3_mutex_enter(pInode->pLockMutex);
    if( pFile->pInode->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pInode->aPending.  It will be automatically closed when
      ** the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    sqlite3_mutex_leave(pInode->pLockMutex);
  }
  releaseInodeInfo(pFile);
  sqlite3_free(pFile->lockingContext);
  rc = closeUnixFile(id);
  unixLeaveMutex();
  return rc;
}
................................................................................
  if( p==0 ) return SQLITE_NOMEM_BKPT;
  memset(p, 0, sizeof(*p));
  assert( pDbFd->pShm==0 );

  /* Check to see if a unixShmNode object already exists. Reuse an existing
  ** one if present. Create a new one if necessary.
  */
  assert( unixFileMutexNotheld(pDbFd) );
  unixEnterMutex();
  pInode = pDbFd->pInode;
  pShmNode = pInode->pShmNode;
  if( pShmNode==0 ){
    struct stat sStat;                 /* fstat() info for database file */
#ifndef SQLITE_SHM_DIRECTORY
    const char *zBasePath = pDbFd->zPath;
................................................................................
** any load or store begun after the barrier.
*/
static void unixShmBarrier(
  sqlite3_file *fd                /* Database file holding the shared memory */
){
  UNUSED_PARAMETER(fd);
  sqlite3MemoryBarrier();         /* compiler-defined memory barrier */
  assert( unixFileMutexNotheld((unixFile*)fd) );
  unixEnterMutex();               /* Also mutex, for redundancy */
  unixLeaveMutex();
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.
................................................................................
  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  sqlite3_mutex_leave(pShmNode->mutex);

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too */
  assert( unixFileMutexNotheld(pDbFd) );
  unixEnterMutex();
  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    if( deleteFlag && pShmNode->h>=0 ){
      osUnlink(pShmNode->zFilename);
    }
................................................................................
  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock,    /* xCheckReservedLock method */
  unixShmMap                /* xShmMap method */
)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */
  3,                        /* shared memory and mmap are enabled */
  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock,  /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
IOMETHODS(
................................................................................
  ** almost certain that an open() call on the same path will also fail.
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a reusable file descriptor are not dire.  */
  if( inodeList!=0 && 0==osStat(zPath, &sStat) ){
    unixInodeInfo *pInode;

    pInode = inodeList;
    while( pInode && (pInode->fileId.dev!=sStat.st_dev
                     || pInode->fileId.ino!=(u64)sStat.st_ino) ){
       pInode = pInode->pNext;
    }
    if( pInode ){
      UnixUnusedFd **pp;
      assert( sqlite3_mutex_notheld(pInode->pLockMutex) );
      sqlite3_mutex_enter(pInode->pLockMutex);
      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
      pUnused = *pp;
      if( pUnused ){

        *pp = pUnused->pNext;
      }
      sqlite3_mutex_leave(pInode->pLockMutex);
    }
  }
  unixLeaveMutex();
#endif    /* if !OS_VXWORKS */
  return pUnused;
}

*/
static void corruptSchema(
  InitData *pData,     /* Initialization context */
  const char *zObj,    /* Object being parsed at the point of error */
  const char *zExtra   /* Error information */
){
  sqlite3 *db = pData->db;







  if( !db->mallocFailed && (db->flags & SQLITE_WriteSchema)==0 ){


    char *z;
    if( zObj==0 ) zObj = "?";
    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
    if( zExtra && zExtra[0] ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);
    sqlite3DbFree(db, *pData->pzErrMsg);
    *pData->pzErrMsg = z;

  }
  pData->rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_CORRUPT_BKPT;
}

/*
** This is the callback routine for the code that initializes the
** database.  See sqlite3Init() below for additional information.
** This routine is also called from the OP_ParseSchema opcode of the VDBE.
**
................................................................................
** Attempt to read the database schema and initialize internal
** data structures for a single database file.  The index of the
** database file is given by iDb.  iDb==0 is used for the main
** database.  iDb==1 should never be used.  iDb>=2 is used for
** auxiliary databases.  Return one of the SQLITE_ error codes to
** indicate success or failure.
*/
int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
  int rc;
  int i;
#ifndef SQLITE_OMIT_DEPRECATED
  int size;
#endif
  Db *pDb;
  char const *azArg[4];
................................................................................
  azArg[2] = "CREATE TABLE x(type text,name text,tbl_name text,"
                            "rootpage int,sql text)";
  azArg[3] = 0;
  initData.db = db;
  initData.iDb = iDb;
  initData.rc = SQLITE_OK;
  initData.pzErrMsg = pzErrMsg;

  sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
  if( initData.rc ){
    rc = initData.rc;
    goto error_out;
  }

  /* Create a cursor to hold the database open
................................................................................
  assert( sqlite3_mutex_held(db->mutex) );
  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
  assert( db->init.busy==0 );
  ENC(db) = SCHEMA_ENC(db);
  assert( db->nDb>0 );
  /* Do the main schema first */
  if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){
    rc = sqlite3InitOne(db, 0, pzErrMsg);
    if( rc ) return rc;
  }
  /* All other schemas after the main schema. The "temp" schema must be last */
  for(i=db->nDb-1; i>0; i--){
    assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );
    if( !DbHasProperty(db, i, DB_SchemaLoaded) ){
      rc = sqlite3InitOne(db, i, pzErrMsg);
      if( rc ) return rc;
    }
  }
  if( commit_internal ){
    sqlite3CommitInternalChanges(db);
  }
  return SQLITE_OK;

*/
static void corruptSchema(
  InitData *pData,     /* Initialization context */
  const char *zObj,    /* Object being parsed at the point of error */
  const char *zExtra   /* Error information */
){
  sqlite3 *db = pData->db;
  if( db->mallocFailed ){
    pData->rc = SQLITE_NOMEM_BKPT;
  }else if( pData->pzErrMsg[0]!=0 ){
    /* A error message has already been generated.  Do not overwrite it */
  }else if( pData->mInitFlags & INITFLAG_AlterTable ){
    *pData->pzErrMsg = sqlite3DbStrDup(db, zExtra);
    pData->rc = SQLITE_ERROR;
  }else if( db->flags & SQLITE_WriteSchema ){
    pData->rc = SQLITE_CORRUPT_BKPT;
  }else{
    char *z;
    if( zObj==0 ) zObj = "?";
    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
    if( zExtra && zExtra[0] ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);

    *pData->pzErrMsg = z;
    pData->rc = SQLITE_CORRUPT_BKPT;
  }

}

/*
** This is the callback routine for the code that initializes the
** database.  See sqlite3Init() below for additional information.
** This routine is also called from the OP_ParseSchema opcode of the VDBE.
**
................................................................................
** Attempt to read the database schema and initialize internal
** data structures for a single database file.  The index of the
** database file is given by iDb.  iDb==0 is used for the main
** database.  iDb==1 should never be used.  iDb>=2 is used for
** auxiliary databases.  Return one of the SQLITE_ error codes to
** indicate success or failure.
*/
int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
  int rc;
  int i;
#ifndef SQLITE_OMIT_DEPRECATED
  int size;
#endif
  Db *pDb;
  char const *azArg[4];
................................................................................
  azArg[2] = "CREATE TABLE x(type text,name text,tbl_name text,"
                            "rootpage int,sql text)";
  azArg[3] = 0;
  initData.db = db;
  initData.iDb = iDb;
  initData.rc = SQLITE_OK;
  initData.pzErrMsg = pzErrMsg;
  initData.mInitFlags = mFlags;
  sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
  if( initData.rc ){
    rc = initData.rc;
    goto error_out;
  }

  /* Create a cursor to hold the database open
................................................................................
  assert( sqlite3_mutex_held(db->mutex) );
  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
  assert( db->init.busy==0 );
  ENC(db) = SCHEMA_ENC(db);
  assert( db->nDb>0 );
  /* Do the main schema first */
  if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){
    rc = sqlite3InitOne(db, 0, pzErrMsg, 0);
    if( rc ) return rc;
  }
  /* All other schemas after the main schema. The "temp" schema must be last */
  for(i=db->nDb-1; i>0; i--){
    assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );
    if( !DbHasProperty(db, i, DB_SchemaLoaded) ){
      rc = sqlite3InitOne(db, i, pzErrMsg, 0);
      if( rc ) return rc;
    }
  }
  if( commit_internal ){
    sqlite3CommitInternalChanges(db);
  }
  return SQLITE_OK;

** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
*/
typedef struct {
  sqlite3 *db;        /* The database being initialized */
  char **pzErrMsg;    /* Error message stored here */
  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
  int rc;             /* Result code stored here */

} InitData;






/*
** Structure containing global configuration data for the SQLite library.
**
** This structure also contains some state information.
*/
struct Sqlite3Config {
  int bMemstat;                     /* True to enable memory status */
................................................................................
void sqlite3ExprListSetSortOrder(ExprList*,int);
void sqlite3ExprListSetName(Parse*,ExprList*,Token*,int);
void sqlite3ExprListSetSpan(Parse*,ExprList*,const char*,const char*);
void sqlite3ExprListDelete(sqlite3*, ExprList*);
u32 sqlite3ExprListFlags(const ExprList*);
int sqlite3Init(sqlite3*, char**);
int sqlite3InitCallback(void*, int, char**, char**);
int sqlite3InitOne(sqlite3*, int, char**);
void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
#ifndef SQLITE_OMIT_VIRTUALTABLE
Module *sqlite3PragmaVtabRegister(sqlite3*,const char *zName);
#endif
void sqlite3ResetAllSchemasOfConnection(sqlite3*);
void sqlite3ResetOneSchema(sqlite3*,int);
void sqlite3CollapseDatabaseArray(sqlite3*);

** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
*/
typedef struct {
  sqlite3 *db;        /* The database being initialized */
  char **pzErrMsg;    /* Error message stored here */
  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
  int rc;             /* Result code stored here */
  u32 mInitFlags;     /* Flags controlling error messages */
} InitData;

/*
** Allowed values for mInitFlags
*/
#define INITFLAG_AlterTable   0x0001  /* This is a reparse after ALTER TABLE */

/*
** Structure containing global configuration data for the SQLite library.
**
** This structure also contains some state information.
*/
struct Sqlite3Config {
  int bMemstat;                     /* True to enable memory status */
................................................................................
void sqlite3ExprListSetSortOrder(ExprList*,int);
void sqlite3ExprListSetName(Parse*,ExprList*,Token*,int);
void sqlite3ExprListSetSpan(Parse*,ExprList*,const char*,const char*);
void sqlite3ExprListDelete(sqlite3*, ExprList*);
u32 sqlite3ExprListFlags(const ExprList*);
int sqlite3Init(sqlite3*, char**);
int sqlite3InitCallback(void*, int, char**, char**);
int sqlite3InitOne(sqlite3*, int, char**, u32);
void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
#ifndef SQLITE_OMIT_VIRTUALTABLE
Module *sqlite3PragmaVtabRegister(sqlite3*,const char *zName);
#endif
void sqlite3ResetAllSchemasOfConnection(sqlite3*);
void sqlite3ResetOneSchema(sqlite3*,int);
void sqlite3CollapseDatabaseArray(sqlite3*);

  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: ParseSchema P1 * * P4 *
**
** Read and parse all entries from the SQLITE_MASTER table of database P1
** that match the WHERE clause P4. 

**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {
  int iDb;
  const char *zMaster;
................................................................................
  assert( iDb>=0 && iDb<db->nDb );
  assert( DbHasProperty(db, iDb, DB_SchemaLoaded) );

#ifndef SQLITE_OMIT_ALTERTABLE
  if( pOp->p4.z==0 ){
    sqlite3SchemaClear(db->aDb[iDb].pSchema);
    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
    rc = sqlite3InitOne(db, iDb, &p->zErrMsg);
    db->mDbFlags |= DBFLAG_SchemaChange;
  }else
#endif
  /* Used to be a conditional */ {
    zMaster = MASTER_NAME;
    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
       db->aDb[iDb].zDbSName, zMaster, pOp->p4.z);

  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: ParseSchema P1 * * P4 *
**
** Read and parse all entries from the SQLITE_MASTER table of database P1
** that match the WHERE clause P4.  If P4 is a NULL pointer, then the
** entire schema for P1 is reparsed.
**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {
  int iDb;
  const char *zMaster;
................................................................................
  assert( iDb>=0 && iDb<db->nDb );
  assert( DbHasProperty(db, iDb, DB_SchemaLoaded) );

#ifndef SQLITE_OMIT_ALTERTABLE
  if( pOp->p4.z==0 ){
    sqlite3SchemaClear(db->aDb[iDb].pSchema);
    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
    rc = sqlite3InitOne(db, iDb, &p->zErrMsg, INITFLAG_AlterTable);
    db->mDbFlags |= DBFLAG_SchemaChange;
  }else
#endif
  {
    zMaster = MASTER_NAME;
    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
       db->aDb[iDb].zDbSName, zMaster, pOp->p4.z);

void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeReusable(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeClearObject(sqlite3*,Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,Parse*);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
#ifdef SQLITE_COVERAGE_TEST
  int sqlite3VdbeLabelHasBeenResolved(Vdbe*,int);
#endif
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  int sqlite3VdbeAssertMayAbort(Vdbe *, int);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
void sqlite3VdbeRewind(Vdbe*);
int sqlite3VdbeReset(Vdbe*);

void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeReusable(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeClearObject(sqlite3*,Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,Parse*);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);



int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  int sqlite3VdbeAssertMayAbort(Vdbe *, int);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
void sqlite3VdbeRewind(Vdbe*);
int sqlite3VdbeReset(Vdbe*);

    }
#endif
    assert( p->aLabel[j]==(-1) ); /* Labels may only be resolved once */
    p->aLabel[j] = v->nOp;
  }
}

#ifdef SQLITE_COVERAGE_TEST
/*
** Return TRUE if and only if the label x has already been resolved.
** Return FALSE (zero) if label x is still unresolved.
**
** This routine is only used inside of testcase() macros, and so it
** only exists when measuring test coverage.
*/
int sqlite3VdbeLabelHasBeenResolved(Vdbe *v, int x){
  return v->pParse->aLabel && v->pParse->aLabel[ADDR(x)]>=0;
}
#endif /* SQLITE_COVERAGE_TEST */

/*
** Mark the VDBE as one that can only be run one time.
*/
void sqlite3VdbeRunOnlyOnce(Vdbe *p){
  p->runOnlyOnce = 1;
}

    }
#endif
    assert( p->aLabel[j]==(-1) ); /* Labels may only be resolved once */
    p->aLabel[j] = v->nOp;
  }
}














/*
** Mark the VDBE as one that can only be run one time.
*/
void sqlite3VdbeRunOnlyOnce(Vdbe *p){
  p->runOnlyOnce = 1;
}

 12 {CREATE TABLE t1(a, b, c);   CREATE INDEX t1i ON t1(b+b+b+b, c) WHERE b>0}
    {{CREATE TABLE t1(a, d, c)} {CREATE INDEX t1i ON t1(d+d+d+d, c) WHERE d>0}}

 13 {CREATE TABLE t1(a, b, c, FOREIGN KEY (b) REFERENCES t2)}
    {CREATE TABLE t1(a, d, c, FOREIGN KEY (d) REFERENCES t2)}
















} {
  reset_db
  do_execsql_test 1.$tn.0 $before

  do_execsql_test 1.$tn.1 {
    INSERT INTO t1 VALUES(1, 2, 3);
  }
................................................................................
} {0 {}}

do_execsql_test 6.3 {
  SELECT "where" FROM blob;
} {}

#-------------------------------------------------------------------------

#
reset_db
do_execsql_test 7.0 {
  CREATE TABLE c(x);
  INSERT INTO c VALUES(0);
  CREATE TABLE t6("col a", "col b", "col c");
  CREATE TRIGGER zzz AFTER UPDATE OF "col a", "col c" ON t6 BEGIN
................................................................................
}

do_execsql_test 7.3 {
  UPDATE t6 SET "col 3" = 0;
  SELECT * FROM c;
} {2}

finish_test

 12 {CREATE TABLE t1(a, b, c);   CREATE INDEX t1i ON t1(b+b+b+b, c) WHERE b>0}
    {{CREATE TABLE t1(a, d, c)} {CREATE INDEX t1i ON t1(d+d+d+d, c) WHERE d>0}}

 13 {CREATE TABLE t1(a, b, c, FOREIGN KEY (b) REFERENCES t2)}
    {CREATE TABLE t1(a, d, c, FOREIGN KEY (d) REFERENCES t2)}

 15 {CREATE TABLE t1(a INTEGER, b INTEGER, c BLOB, PRIMARY KEY(b))}
    {CREATE TABLE t1(a INTEGER, d INTEGER, c BLOB, PRIMARY KEY(d))}

 16 {CREATE TABLE t1(a INTEGER, b INTEGER PRIMARY KEY, c BLOB)}
    {CREATE TABLE t1(a INTEGER, d INTEGER PRIMARY KEY, c BLOB)}

 14 {CREATE TABLE t1(a INTEGER, b TEXT, c BLOB, PRIMARY KEY(b))}
    {CREATE TABLE t1(a INTEGER, d TEXT, c BLOB, PRIMARY KEY(d))}

 15 {CREATE TABLE t1(a INTEGER, b INTEGER, c BLOB, PRIMARY KEY(b))}
    {CREATE TABLE t1(a INTEGER, d INTEGER, c BLOB, PRIMARY KEY(d))}

 16 {CREATE TABLE t1(a INTEGER, b INTEGER PRIMARY KEY, c BLOB)}
    {CREATE TABLE t1(a INTEGER, d INTEGER PRIMARY KEY, c BLOB)}

} {
  reset_db
  do_execsql_test 1.$tn.0 $before

  do_execsql_test 1.$tn.1 {
    INSERT INTO t1 VALUES(1, 2, 3);
  }
................................................................................
} {0 {}}

do_execsql_test 6.3 {
  SELECT "where" FROM blob;
} {}

#-------------------------------------------------------------------------
# Triggers.
#
reset_db
do_execsql_test 7.0 {
  CREATE TABLE c(x);
  INSERT INTO c VALUES(0);
  CREATE TABLE t6("col a", "col b", "col c");
  CREATE TRIGGER zzz AFTER UPDATE OF "col a", "col c" ON t6 BEGIN
................................................................................
}

do_execsql_test 7.3 {
  UPDATE t6 SET "col 3" = 0;
  SELECT * FROM c;
} {2}


#-------------------------------------------------------------------------
# Views.
#
reset_db
do_execsql_test 8.0 {
  CREATE TABLE a1(x INTEGER, y TEXT, z BLOB, PRIMARY KEY(x));
  CREATE TABLE a2(a, b, c);
  CREATE VIEW v1 AS SELECT x, y, z FROM a1;
}

do_execsql_test 8.1 {
  ALTER TABLE a1 RENAME y TO yyy;
  SELECT sql FROM sqlite_master WHERE type='view';
} {{CREATE VIEW v1 AS SELECT x, yyy, z FROM a1}}

do_execsql_test 8.2.1 {
  DROP VIEW v1;
  CREATE VIEW v2 AS SELECT x, x+x, a, a+a FROM a1, a2;
} {}
do_execsql_test 8.2.2 {
  ALTER TABLE a1 RENAME x TO xxx;
}
do_execsql_test 8.2.3 {
  SELECT sql FROM sqlite_master WHERE type='view';
} {{CREATE VIEW v2 AS SELECT xxx, xxx+xxx, a, a+a FROM a1, a2}}

do_execsql_test 8.3.1 {
  DROP TABLE a2;
  DROP VIEW v2;
  CREATE TABLE a2(a INTEGER PRIMARY KEY, b, c);
  CREATE VIEW v2 AS SELECT xxx, xxx+xxx, a, a+a FROM a1, a2;
} {}
do_execsql_test 8.3.2 {
  ALTER TABLE a1 RENAME xxx TO x;
}
do_execsql_test 8.3.3 {
  SELECT sql FROM sqlite_master WHERE type='view';
} {{CREATE VIEW v2 AS SELECT x, x+x, a, a+a FROM a1, a2}}

do_execsql_test 8.4.0 {
  CREATE TABLE b1(a, b, c);
  CREATE TABLE b2(x, y, z);
}

do_execsql_test 8.4.1 {
  CREATE VIEW vvv AS SELECT c+c || coalesce(c, c) FROM b1, b2 WHERE x=c GROUP BY c HAVING c>0;
  ALTER TABLE b1 RENAME c TO "a;b";
  SELECT sql FROM sqlite_master WHERE name='vvv';
} {{CREATE VIEW vvv AS SELECT "a;b"+"a;b" || coalesce("a;b", "a;b") FROM b1, b2 WHERE x="a;b" GROUP BY "a;b" HAVING "a;b">0}}

do_execsql_test 8.4.2 {
  CREATE VIEW www AS SELECT b FROM b1 UNION ALL SELECT y FROM b2;
  ALTER TABLE b1 RENAME b TO bbb;
  SELECT sql FROM sqlite_master WHERE name='www';
} {{CREATE VIEW www AS SELECT bbb FROM b1 UNION ALL SELECT y FROM b2}}

db collate nocase {string compare}

do_execsql_test 8.4.3 {
  CREATE VIEW xxx AS SELECT a FROM b1 UNION SELECT x FROM b2 ORDER BY 1 COLLATE nocase;
}

do_execsql_test 8.4.4 {
  ALTER TABLE b2 RENAME x TO hello;
  SELECT sql FROM sqlite_master WHERE name='xxx';
} {{CREATE VIEW xxx AS SELECT a FROM b1 UNION SELECT hello FROM b2 ORDER BY 1 COLLATE nocase}}

do_execsql_test 8.4.5 {
  CREATE VIEW zzz AS SELECT george, ringo FROM b1;
  ALTER TABLE b1 RENAME a TO aaa;
  SELECT sql FROM sqlite_master WHERE name = 'zzz'
} {{CREATE VIEW zzz AS SELECT george, ringo FROM b1}}


finish_test

  execsql {
    PRAGMA writable_schema=on;
    UPDATE sqlite_master SET sql='nonsense';
  }
  db close
  catch { sqlite3 db test.db }
  catchsql { DROP TRIGGER t2r5 }
} {1 {malformed database schema (t2r12)}}

finish_test

  execsql {
    PRAGMA writable_schema=on;
    UPDATE sqlite_master SET sql='nonsense';
  }
  db close
  catch { sqlite3 db test.db }
  catchsql { DROP TRIGGER t2r5 }
} {/1 {malformed database schema .*}/}

finish_test

  PRAGMA integrity_check;
} {ok}
do_execsql_test upsert1-610 {
  DELETE FROM t1;
  INSERT OR IGNORE INTO t1(a) VALUES('1'),(1) ON CONFLICT(a) DO NOTHING;
  PRAGMA integrity_check;
} {ok}




















































































finish_test

  PRAGMA integrity_check;
} {ok}
do_execsql_test upsert1-610 {
  DELETE FROM t1;
  INSERT OR IGNORE INTO t1(a) VALUES('1'),(1) ON CONFLICT(a) DO NOTHING;
  PRAGMA integrity_check;
} {ok}

# 2018-08-14
# Ticket https://www.sqlite.org/src/info/908f001483982c43
# If there are multiple uniqueness contraints, the UPSERT should fire
# if the one constraint it targets fails, regardless of whether or not
# the other constraints pass or fail.  In other words, the UPSERT constraint
# should be tested first.
#
do_execsql_test upsert1-700 {
  DROP TABLE t1;
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT, c INT, d INT, e INT);
  CREATE UNIQUE INDEX t1b ON t1(b);
  CREATE UNIQUE INDEX t1e ON t1(e);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(e) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-710 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(a) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-720 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(b) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-730 {
  DROP TABLE t1;
  CREATE TABLE t1(a INT, b INT, c INT, d INT, e INT);
  CREATE UNIQUE INDEX t1a ON t1(a);
  CREATE UNIQUE INDEX t1b ON t1(b);
  CREATE UNIQUE INDEX t1e ON t1(e);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(e) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-740 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(a) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-750 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(b) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-760 {
  DROP TABLE t1;
  CREATE TABLE t1(a INT PRIMARY KEY, b INT, c INT, d INT, e INT) WITHOUT ROWID;
  CREATE UNIQUE INDEX t1a ON t1(a);
  CREATE UNIQUE INDEX t1b ON t1(b);
  CREATE UNIQUE INDEX t1e ON t1(e);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(e) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-770 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(a) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-780 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(b) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}


finish_test