Support BigQuery SAFE_CAST (#1622) (#1634)

Co-authored-by: Zhang, Dequn <deqzhang@paypal.com>

Author: dequn

src/main/java/net/sf/jsqlparser/expression/ExpressionVisitor.java

@@ -119,6 +119,8 @@ public interface ExpressionVisitor {
 
     void visit(TryCastExpression cast);
 
+    void visit(SafeCastExpression cast);
+
     void visit(Modulo modulo);
 
     void visit(AnalyticExpression aexpr);

src/main/java/net/sf/jsqlparser/expression/ExpressionVisitorAdapter.java

@@ -315,6 +315,11 @@ public void visit(TryCastExpression expr) {
         expr.getLeftExpression().accept(this);
     }
 
+    @Override
+    public void visit(SafeCastExpression expr) {
+        expr.getLeftExpression().accept(this);
+    }
+
     @Override
     public void visit(Modulo expr) {
         visitBinaryExpression(expr);

src/main/java/net/sf/jsqlparser/expression/SafeCastExpression.java

@@ -0,0 +1,95 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2019 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.expression;
+
+import net.sf.jsqlparser.parser.ASTNodeAccessImpl;
+import net.sf.jsqlparser.statement.create.table.ColDataType;
+
+public class SafeCastExpression extends ASTNodeAccessImpl implements Expression {
+
+    private Expression leftExpression;
+    private ColDataType type;
+    private RowConstructor rowConstructor;
+    private boolean useCastKeyword = true;
+
+    public RowConstructor getRowConstructor() {
+        return rowConstructor;
+    }
+
+    public void setRowConstructor(RowConstructor rowConstructor) {
+        this.rowConstructor = rowConstructor;
+        this.type = null;
+    }
+
+    public SafeCastExpression withRowConstructor(RowConstructor rowConstructor) {
+        setRowConstructor(rowConstructor);
+        return this;
+    }
+
+    public ColDataType getType() {
+        return type;
+    }
+
+    public void setType(ColDataType type) {
+        this.type = type;
+        this.rowConstructor = null;
+    }
+
+    public Expression getLeftExpression() {
+        return leftExpression;
+    }
+
+    public void setLeftExpression(Expression expression) {
+        leftExpression = expression;
+    }
+
+    @Override
+    public void accept(ExpressionVisitor expressionVisitor) {
+        expressionVisitor.visit(this);
+    }
+
+    public boolean isUseCastKeyword() {
+        return useCastKeyword;
+    }
+
+    public void setUseCastKeyword(boolean useCastKeyword) {
+        this.useCastKeyword = useCastKeyword;
+    }
+
+    @Override
+    public String toString() {
+        if (useCastKeyword) {
+            return rowConstructor!=null
+              ? "SAFE_CAST(" + leftExpression + " AS " + rowConstructor.toString() + ")"
+              : "SAFE_CAST(" + leftExpression + " AS " + type.toString() + ")";
+        } else {
+            return leftExpression + "::" + type.toString();
+        }
+    }
+
+    public SafeCastExpression withType(ColDataType type) {
+        this.setType(type);
+        return this;
+    }
+
+    public SafeCastExpression withUseCastKeyword(boolean useCastKeyword) {
+        this.setUseCastKeyword(useCastKeyword);
+        return this;
+    }
+
+    public SafeCastExpression withLeftExpression(Expression leftExpression) {
+        this.setLeftExpression(leftExpression);
+        return this;
+    }
+
+    public <E extends Expression> E getLeftExpression(Class<E> type) {
+        return type.cast(getLeftExpression());
+    }
+}

src/main/java/net/sf/jsqlparser/util/TablesNamesFinder.java

@@ -474,6 +474,11 @@ public void visit(TryCastExpression cast) {
         cast.getLeftExpression().accept(this);
     }
 
+    @Override
+    public void visit(SafeCastExpression cast) {
+        cast.getLeftExpression().accept(this);
+    }
+
     @Override
     public void visit(Modulo modulo) {
         visitBinaryExpression(modulo);

src/main/java/net/sf/jsqlparser/util/deparser/ExpressionDeParser.java

@@ -622,6 +622,22 @@ public void visit(TryCastExpression cast) {
         }
     }
 
+    @Override
+    public void visit(SafeCastExpression cast) {
+        if (cast.isUseCastKeyword()) {
+            buffer.append("SAFE_CAST(");
+            cast.getLeftExpression().accept(this);
+            buffer.append(" AS ");
+            buffer.append(cast.getRowConstructor() != null ? cast.getRowConstructor() : cast.getType());
+            buffer.append(")");
+        } else {
+            cast.getLeftExpression().accept(this);
+            buffer.append("::");
+            buffer.append(cast.getType());
+        }
+
+    }
+
     @Override
     public void visit(Modulo modulo) {
         visitBinaryExpression(modulo, " % ");

src/main/java/net/sf/jsqlparser/util/validation/validator/ExpressionValidator.java

@@ -362,6 +362,12 @@ public void visit(TryCastExpression cast) {
         cast.getLeftExpression().accept(this);
     }
 
+    @Override
+    public void visit(SafeCastExpression cast) {
+        cast.getLeftExpression().accept(this);
+
+    }
+
     @Override
     public void visit(Modulo modulo) {
         visitBinaryExpression(modulo, " % ");

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -158,6 +158,7 @@ TOKEN: /* SQL Keywords. prefixed with K_ to avoid name clashes */
 |   <K_CASEWHEN:"CASEWHEN">  /* H2 casewhen function */
 |   <K_CAST: "CAST">
 |   <K_TRY_CAST: "TRY_CAST">
+|   <K_SAFE_CAST: "SAFE_CAST">
 |   <K_CHARACTER:"CHARACTER">
 |   <K_CHANGE:"CHANGE">
 |   <K_CHANGES:"CHANGES">
@@ -1821,7 +1822,7 @@ String RelObjectNameWithoutValue() :
     (tk=<S_IDENTIFIER> | tk=<S_QUOTED_IDENTIFIER> 
       | tk=<K_ALGORITHM> | tk=<K_AT>
       | tk=<K_BYTE> | tk=<K_CHAR> | tk=<K_CHANGE> | tk=<K_CHARACTER>
-      | tk=<K_CAST> | tk =<K_TRY_CAST> | tk=<K_COMMENT> | tk=<K_COSTS> | tk=<K_DISABLE> | tk=<K_DESC>
+      | tk=<K_CAST> | tk =<K_TRY_CAST> | tk =<K_SAFE_CAST> | tk=<K_COMMENT> | tk=<K_COSTS> | tk=<K_DISABLE> | tk=<K_DESC>
       | tk=<K_DO> | tk=<K_DEFAULT> | tk=<K_EXTRACT> | tk=<K_FILTER> | tk=<K_FIRST> | tk=<K_FOLLOWING> | tk=<K_JSON>
       | tk=<K_LAST> | tk=<K_LEADING> | tk=<K_MATERIALIZED> | tk=<K_NULLS> | tk=<K_PARTITION> | tk=<K_RANGE>
       | tk=<K_ROW> | tk=<K_ROWS> | tk=<K_SIBLINGS> | tk=<K_XML>
@@ -4002,6 +4003,8 @@ Expression PrimaryExpression() #PrimaryExpression:
 
         | LOOKAHEAD(2, {!interrupted}) retval=TryCastExpression()
 
+        | LOOKAHEAD(2, {!interrupted}) retval=SafeCastExpression()
+
         //| LOOKAHEAD(2) retval=RowConstructor()
 
         // support timestamp expressions
@@ -4641,6 +4644,30 @@ TryCastExpression TryCastExpression():
     }
 }
 
+SafeCastExpression SafeCastExpression():
+{
+    SafeCastExpression retval = new SafeCastExpression();
+    ColDataType type = null;
+    RowConstructor rowConstructor = null;
+    Expression expression = null;
+    boolean    useCastKeyword;
+}
+{
+    <K_SAFE_CAST>
+    "("
+    expression=SimpleExpression()
+    <K_AS> { retval.setUseCastKeyword(true); }
+    (
+        LOOKAHEAD(3) rowConstructor = RowConstructor() { retval.setRowConstructor(rowConstructor); }
+        | type=ColDataType() { retval.setType(type); }
+    )
+    ")"
+
+    {
+        retval.setLeftExpression(expression);
+        return retval;
+    }
+}
 Expression CaseWhenExpression() #CaseWhenExpression:
 {
     CaseExpression caseExp = new CaseExpression();

src/test/java/net/sf/jsqlparser/expression/SafeCastExpressionTest.java

@@ -0,0 +1,23 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2022 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.expression;
+
+import net.sf.jsqlparser.JSQLParserException;
+import net.sf.jsqlparser.test.TestUtils;
+import org.junit.jupiter.api.Test;
+
+public class SafeCastExpressionTest {
+
+    @Test
+    public void testSafeCast() throws JSQLParserException {
+        TestUtils.assertExpressionCanBeParsedAndDeparsed("SAFE_CAST(ROW(dataid, value, calcMark) AS ROW(datapointid CHAR, value CHAR, calcMark CHAR))", true);
+        TestUtils.assertExpressionCanBeParsedAndDeparsed("SAFE_CAST(ROW(dataid, value, calcMark) AS testcol)", true);
+    }
+}