content: /*
   * Copyright 1999-2017 Alibaba Group Holding Ltd.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.druid.wall.spi;
  
  import com.alibaba.druid.DbType;
  import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
  import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
  import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
  import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
  import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
  import com.alibaba.druid.sql.dialect.sqlserver.ast.SQLServerSelectQueryBlock;
  import com.alibaba.druid.sql.dialect.sqlserver.ast.expr.SQLServerObjectReferenceExpr;
  import com.alibaba.druid.sql.dialect.sqlserver.ast.stmt.SQLServerExecStatement;
  import com.alibaba.druid.sql.dialect.sqlserver.ast.stmt.SQLServerUpdateStatement;
  import com.alibaba.druid.sql.dialect.sqlserver.visitor.SQLServerASTVisitor;
  import com.alibaba.druid.wall.WallProvider;
  import com.alibaba.druid.wall.WallVisitor;
  import com.alibaba.druid.wall.spi.WallVisitorUtils.WallTopStatementContext;
  import com.alibaba.druid.wall.violation.ErrorCode;
  import com.alibaba.druid.wall.violation.IllegalSQLObjectViolation;
  
  public class SQLServerWallVisitor extends WallVisitorBase implements WallVisitor, SQLServerASTVisitor {
      public SQLServerWallVisitor(WallProvider provider) {
          super(provider);
      }
  
      @Override
      public DbType getDbType() {
          return DbType.sqlserver;
      }
  
      @Override
      public boolean isDenyTable(String name) {
          if (!config.isTableCheck()) {
              return false;
          }
  
          return !this.provider.checkDenyTable(name);
      }
  
      public boolean visit(SQLIdentifierExpr x) {
          // String name = x.getName();
          // name = WallVisitorUtils.form(name);
          // if (config.isVariantCheck() && config.getDenyVariants().contains(name)) {
          // getViolations().add(new IllegalSQLObjectViolation(ErrorCode.VARIANT_DENY, "variable not allow : " + name,
          // toSQL(x)));
          // }
          return true;
      }
  
      @Override
      public boolean visit(SQLMethodInvokeExpr x) {
          if (x.getParent() instanceof SQLExprTableSource) {
              WallVisitorUtils.checkFunctionInTableSource(this, x);
          }
  
          WallVisitorUtils.checkFunction(this, x);
  
          return true;
      }
  
      @Override
      public boolean visit(SQLServerExecStatement x) {
          return false;
      }
  
      public boolean visit(SQLVariantRefExpr x) {
          String varName = x.getName();
          if (varName == null) {
              return false;
          }
  
          if (config.isVariantCheck() && varName.startsWith("@@")) {
              final WallTopStatementContext topStatementContext = WallVisitorUtils.getWallTopStatementContext();
              if (topStatementContext != null
                      && (topStatementContext.fromSysSchema() || topStatementContext.fromSysTable())) {
                  return false;
              }
  
              boolean allow = true;
              if (isDeny(varName) && (WallVisitorUtils.isWhereOrHaving(x) || WallVisitorUtils.checkSqlExpr(x))) {
                  allow = false;
              }
  
              if (!allow) {
                  violations.add(new IllegalSQLObjectViolation(ErrorCode.VARIANT_DENY, "variable not allow : "
                          + x.getName(), toSQL(x)));
              }
          }
  
          return false;
      }
  
      public boolean isDeny(String varName) {
          if (varName.startsWith("@@")) {
              varName = varName.substring(2);
          }
  
          return config.getDenyVariants().contains(varName);
      }
  
      @Override
      public boolean visit(SQLServerObjectReferenceExpr x) {
          return false;
      }
  
      public boolean visit(SQLServerSelectQueryBlock x) {
          WallVisitorUtils.checkSelect(this, x);
          return true;
      }
      @Override
      public boolean visit(SQLServerUpdateStatement x) {
          return visit((SQLUpdateStatement) x);
      }
  
  }
  