Merge pull request #691 from yakolee/master

improve sqlwall

src/main/java/com/alibaba/druid/sql/ast/expr/SQLCharExpr.java

@@ -17,7 +17,7 @@ package com.alibaba.druid.sql.ast.expr;
 
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class SQLCharExpr extends SQLTextLiteralExpr {
+public class SQLCharExpr extends SQLTextLiteralExpr implements SQLValuableExpr{
 
     public SQLCharExpr(){
 
@@ -42,4 +42,9 @@ public class SQLCharExpr extends SQLTextLiteralExpr {
         visitor.visit(this);
         visitor.endVisit(this);
     }
+
+    @Override
+    public Object getValue() {
+        return this.text;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLIntegerExpr.java

@@ -17,7 +17,7 @@ package com.alibaba.druid.sql.ast.expr;
 
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class SQLIntegerExpr extends SQLNumericLiteralExpr {
+public class SQLIntegerExpr extends SQLNumericLiteralExpr implements SQLValuableExpr{
 
     private Number number;
 
@@ -77,4 +77,9 @@ public class SQLIntegerExpr extends SQLNumericLiteralExpr {
         }
         return true;
     }
+
+    @Override
+    public Object getValue() {
+        return this.number;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLNullExpr.java

@@ -18,7 +18,9 @@ package com.alibaba.druid.sql.ast.expr;
 import com.alibaba.druid.sql.ast.SQLExprImpl;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class SQLNullExpr extends SQLExprImpl implements SQLLiteralExpr {
+import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE_NULL;
+
+public class SQLNullExpr extends SQLExprImpl implements SQLLiteralExpr, SQLValuableExpr {
 
     public SQLNullExpr(){
 
@@ -41,4 +43,9 @@ public class SQLNullExpr extends SQLExprImpl implements SQLLiteralExpr {
     public boolean equals(Object o) {
         return o instanceof SQLNullExpr;
     }
+
+    @Override
+    public Object getValue() {
+        return EVAL_VALUE_NULL;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLValuableExpr.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 1999-2011 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.sql.ast.expr;
+
+import com.alibaba.druid.sql.ast.SQLExpr;
+
+public interface SQLValuableExpr extends SQLExpr {
+
+    Object getValue();
+
+}

src/main/java/com/alibaba/druid/wall/spi/MySqlWallVisitor.java

@@ -403,7 +403,7 @@ public class MySqlWallVisitor extends MySqlASTVisitorAdapter implements WallVisi
     @Override
     public boolean visit(SQLCreateTableStatement x) {
         WallVisitorUtils.check(this, x);
-        return true;
+        return false;
     }
 
     @Override

src/main/java/com/alibaba/druid/wall/spi/SQLServerWallVisitor.java

@@ -304,7 +304,7 @@ public class SQLServerWallVisitor extends SQLServerASTVisitorAdapter implements
     @Override
     public boolean visit(SQLCreateTableStatement x) {
         WallVisitorUtils.check(this, x);
-        return true;
+        return false;
     }
 
     @Override

src/main/java/com/alibaba/druid/wall/spi/WallVisitorUtils.java

@@ -59,6 +59,7 @@ import com.alibaba.druid.sql.ast.expr.SQLNumericLiteralExpr;
 import com.alibaba.druid.sql.ast.expr.SQLPropertyExpr;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
 import com.alibaba.druid.sql.ast.expr.SQLUnaryExpr;
+import com.alibaba.druid.sql.ast.expr.SQLValuableExpr;
 import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
 import com.alibaba.druid.sql.ast.statement.SQLAlterTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLCallStatement;
@@ -944,47 +945,6 @@ public class WallVisitorUtils {
     }
 
     public static Object getValue(WallVisitor visitor, SQLBinaryOpExpr x) {
-        if (x.getLeft() instanceof SQLName && x.getRight() instanceof SQLName) {
-            if (x.getLeft().toString().equalsIgnoreCase(x.getRight().toString())) {
-                if (x.getOperator() == SQLBinaryOperator.Equality) {
-                    return Boolean.TRUE;
-                } else if (x.getOperator() == SQLBinaryOperator.NotEqual) {
-                    return Boolean.FALSE;
-                }
-
-                switch (x.getOperator()) {
-                    case Equality:
-                    case Like:
-                        return Boolean.TRUE;
-                    case NotEqual:
-                    case GreaterThan:
-                    case GreaterThanOrEqual:
-                    case LessThan:
-                    case LessThanOrEqual:
-                    case LessThanOrGreater:
-                    case NotLike:
-                        return Boolean.FALSE;
-                    default:
-                        break;
-                }
-            }
-        }
-
-        if (x.getLeft() instanceof SQLName && !(x.getRight() instanceof SQLName)) {
-            switch (x.getOperator()) {
-                case Equality:
-                case NotEqual:
-                case GreaterThan:
-                case GreaterThanOrEqual:
-                case LessThan:
-                case LessThanOrEqual:
-                case LessThanOrGreater:
-                    return null;
-                default:
-                    break;
-            }
-        }
-
         if (x.getOperator() == SQLBinaryOperator.BooleanOr) {
             List<SQLExpr> groupList = SQLUtils.split(x);
 
@@ -1058,6 +1018,55 @@ public class WallVisitorUtils {
             return null;
         }
 
+        if (x.getLeft() instanceof SQLName) {
+            if (x.getRight() instanceof SQLName) {
+                if (x.getLeft().toString().equalsIgnoreCase(x.getRight().toString())) {
+                    switch (x.getOperator()) {
+                        case Equality:
+                        case Like:
+                            return Boolean.TRUE;
+                        case NotEqual:
+                        case GreaterThan:
+                        case GreaterThanOrEqual:
+                        case LessThan:
+                        case LessThanOrEqual:
+                        case LessThanOrGreater:
+                        case NotLike:
+                            return Boolean.FALSE;
+                        default:
+                            break;
+                    }
+                }
+            } else {
+                switch (x.getOperator()) {
+                    case Equality:
+                    case NotEqual:
+                    case GreaterThan:
+                    case GreaterThanOrEqual:
+                    case LessThan:
+                    case LessThanOrEqual:
+                    case LessThanOrGreater:
+                        return null;
+                    default:
+                        break;
+                }
+            }
+        }
+
+        if (x.getLeft() instanceof SQLValuableExpr && x.getRight() instanceof SQLValuableExpr) {
+            Object leftValue = ((SQLValuableExpr) x.getLeft()).getValue();
+            Object rightValue = ((SQLValuableExpr) x.getRight()).getValue();
+            if (x.getOperator() == SQLBinaryOperator.Equality) {
+                boolean evalValue = SQLEvalVisitorUtils.eq(leftValue, rightValue);
+                x.putAttribute(EVAL_VALUE, evalValue);
+                return evalValue;
+            } else if (x.getOperator() == SQLBinaryOperator.NotEqual) {
+                boolean evalValue = SQLEvalVisitorUtils.eq(leftValue, rightValue);
+                x.putAttribute(EVAL_VALUE, !evalValue);
+                return !evalValue;
+            }
+        }
+
         if (x.getOperator() == SQLBinaryOperator.Like || x.getOperator() == SQLBinaryOperator.NotLike) {
             Object leftResult = getValue(visitor, x.getLeft());
             Object rightResult = getValue(visitor, x.getRight());
@@ -1083,6 +1092,7 @@ public class WallVisitorUtils {
 
         return eval(visitor, dbType, x, Collections.emptyList());
     }
+    
 
     public static SQLExpr getFirst(SQLExpr x) {
         if (x instanceof SQLBinaryOpExpr) {