anchor oracle hint pattern to avoid quadratic backtracking

Author: dxbjavid

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

@@ -24,7 +24,7 @@ public class OracleHint extends ASTNodeAccessImpl implements Expression {
 
     private static final Pattern SINGLE_LINE = Pattern.compile("--\\+ *([^ ].*[^ ])");
     private static final Pattern MULTI_LINE =
-            Pattern.compile("/\\*\\+ *([^ ].*[^ ]) *\\*+/", Pattern.MULTILINE | Pattern.DOTALL);
+            Pattern.compile("\\A/\\*\\+ *([^ ].*[^ ]) *\\*+/", Pattern.MULTILINE | Pattern.DOTALL);
 
     private String value;
     private boolean singleLine = false;

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

@@ -9,6 +9,10 @@
  */
 package net.sf.jsqlparser.expression;
 
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTimeoutPreemptively;
+
+import java.time.Duration;
 import net.sf.jsqlparser.JSQLParserException;
 import net.sf.jsqlparser.test.TestUtils;
 import org.junit.jupiter.api.Test;
@@ -46,4 +50,18 @@ void testMerge() throws JSQLParserException {
         TestUtils.assertSqlCanBeParsedAndDeparsed(sqlString, true);
     }
 
+    @Test
+    void testCraftedHintCommentDoesNotBacktrack() {
+        final StringBuilder sb = new StringBuilder("-- /*+ ");
+        for (int i = 0; i < 100000; i++) {
+            sb.append('*');
+        }
+        final String crafted = sb.toString();
+
+        // a line comment carrying an unterminated /*+ marker (no closing */) used to make the
+        // block hint pattern backtrack quadratically, and it is not an oracle hint anyway
+        assertTimeoutPreemptively(Duration.ofSeconds(2),
+                () -> assertFalse(OracleHint.isHintMatch(crafted)));
+    }
+
 }