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Posted to dev@tomcat.apache.org by ma...@apache.org on 2022/10/28 08:25:07 UTC
[tomcat] branch 9.0.x updated: Fix BZ 66325 - Correct concurrency issue in lambda expression evaluation
This is an automated email from the ASF dual-hosted git repository.
markt pushed a commit to branch 9.0.x
in repository https://gitbox.apache.org/repos/asf/tomcat.git
The following commit(s) were added to refs/heads/9.0.x by this push:
new 60cc92a25d Fix BZ 66325 - Correct concurrency issue in lambda expression evaluation
60cc92a25d is described below
commit 60cc92a25ddc0f0532c437e11b4d2eae5c7d77ac
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Fri Oct 28 09:23:01 2022 +0100
Fix BZ 66325 - Correct concurrency issue in lambda expression evaluation
https://bz.apache.org/bugzilla/show_bug.cgi?id=66325
---
java/org/apache/el/lang/EvaluationContext.java | 35 +++++++++++++
.../el/lang/LambdaExpressionNestedState.java | 51 +++++++++++++++++++
java/org/apache/el/parser/AstLambdaExpression.java | 57 +++++-----------------
webapps/docs/changelog.xml | 8 +++
4 files changed, 107 insertions(+), 44 deletions(-)
diff --git a/java/org/apache/el/lang/EvaluationContext.java b/java/org/apache/el/lang/EvaluationContext.java
index c69f852173..f62080f34f 100644
--- a/java/org/apache/el/lang/EvaluationContext.java
+++ b/java/org/apache/el/lang/EvaluationContext.java
@@ -27,6 +27,8 @@ import javax.el.FunctionMapper;
import javax.el.ImportHandler;
import javax.el.VariableMapper;
+import org.apache.el.util.MessageFactory;
+
public final class EvaluationContext extends ELContext {
private final ELContext elContext;
@@ -35,6 +37,8 @@ public final class EvaluationContext extends ELContext {
private final VariableMapper varMapper;
+ private LambdaExpressionNestedState lambdaExpressionNestedState;
+
public EvaluationContext(ELContext elContext, FunctionMapper fnMapper,
VariableMapper varMapper) {
this.elContext = elContext;
@@ -153,4 +157,35 @@ public final class EvaluationContext extends ELContext {
public Object convertToType(Object obj, Class<?> type) {
return elContext.convertToType(obj, type);
}
+
+
+ public LambdaExpressionNestedState getLambdaExpressionNestedState() {
+ // State is stored in the EvaluationContext instance associated with the
+ // outermost lambda expression of a set of nested expressions.
+
+ if (lambdaExpressionNestedState != null) {
+ // This instance is storing state so it must be associated with the
+ // outermost lambda expression.
+ return lambdaExpressionNestedState;
+ }
+
+ // Check to see if the associated lambda expression is nested as state
+ // will be stored in the EvaluationContext associated with the outermost
+ // lambda expression.
+ if (elContext instanceof EvaluationContext) {
+ return ((EvaluationContext) elContext).getLambdaExpressionNestedState();
+ }
+
+ return null;
+ }
+
+
+ public void setLambdaExpressionNestedState(LambdaExpressionNestedState lambdaExpressionNestedState) {
+ if (this.lambdaExpressionNestedState != null) {
+ // Should never happen
+ throw new IllegalStateException(MessageFactory.get("error.lambda.wrongNestedState"));
+ }
+
+ this.lambdaExpressionNestedState = lambdaExpressionNestedState;
+ }
}
diff --git a/java/org/apache/el/lang/LambdaExpressionNestedState.java b/java/org/apache/el/lang/LambdaExpressionNestedState.java
new file mode 100644
index 0000000000..f4a4d47c70
--- /dev/null
+++ b/java/org/apache/el/lang/LambdaExpressionNestedState.java
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.el.lang;
+
+/**
+ * Stores the state required for correct evaluation of lambda expressions.
+ * Lambda expressions may be nested. Correct evaluation requires knowledge not
+ * just of the current lambda expression, but also of any nested and nesting
+ * expressions.
+ * <p>
+ * The sets of nodes for parsed expressions are cached and, as a result, a set
+ * of nodes may be being used by multiple concurrent threads. This means any
+ * state relating to evaluation cannot be stored in the nodes. State is
+ * therefore stored in the {@link EvaluationContext} which is created, used for
+ * a single evaluation and then discarded.
+ */
+public final class LambdaExpressionNestedState {
+
+ private int nestingCount = 0;
+ private boolean hasFormalParameters = false;
+
+ public void incrementNestingCount() {
+ nestingCount++;
+ }
+
+ public int getNestingCount() {
+ return nestingCount;
+ }
+
+ public void setHasFormalParameters() {
+ hasFormalParameters = true;
+ }
+
+ public boolean getHasFormalParameters() {
+ return hasFormalParameters;
+ }
+}
diff --git a/java/org/apache/el/parser/AstLambdaExpression.java b/java/org/apache/el/parser/AstLambdaExpression.java
index f719c33553..97a059fca7 100644
--- a/java/org/apache/el/parser/AstLambdaExpression.java
+++ b/java/org/apache/el/parser/AstLambdaExpression.java
@@ -25,12 +25,11 @@ import javax.el.LambdaExpression;
import org.apache.el.ValueExpressionImpl;
import org.apache.el.lang.EvaluationContext;
+import org.apache.el.lang.LambdaExpressionNestedState;
import org.apache.el.util.MessageFactory;
public class AstLambdaExpression extends SimpleNode {
- private NestedState nestedState = null;
-
public AstLambdaExpression(int id) {
super(id);
}
@@ -40,7 +39,14 @@ public class AstLambdaExpression extends SimpleNode {
// Correct evaluation requires knowledge of the whole set of nested
// expressions, not just the current expression
- NestedState state = getNestedState();
+ LambdaExpressionNestedState state = ctx.getLambdaExpressionNestedState();
+ if (state == null) {
+ // This must be an outer lambda expression. Create and populate the
+ // state.
+ state = new LambdaExpressionNestedState();
+ populateNestedState(state);
+ ctx.setLambdaExpressionNestedState(state);
+ }
// Check that there are not more sets of parameters than there are
// nested expressions.
@@ -109,29 +115,15 @@ public class AstLambdaExpression extends SimpleNode {
}
- private NestedState getNestedState() {
- if (nestedState == null) {
- setNestedState(new NestedState());
- }
- return nestedState;
- }
-
-
- private void setNestedState(NestedState nestedState) {
- if (this.nestedState != null) {
- // Should never happen
- throw new IllegalStateException(MessageFactory.get("error.lambda.wrongNestedState"));
- }
- this.nestedState = nestedState;
-
+ private void populateNestedState(LambdaExpressionNestedState lambdaExpressionNestedState) {
// Increment the nesting count for the current expression
- nestedState.incrementNestingCount();
+ lambdaExpressionNestedState.incrementNestingCount();
if (jjtGetNumChildren() > 1) {
Node firstChild = jjtGetChild(0);
if (firstChild instanceof AstLambdaParameters) {
if (firstChild.jjtGetNumChildren() > 0) {
- nestedState.setHasFormalParameters();
+ lambdaExpressionNestedState.setHasFormalParameters();
}
} else {
// Can't be a lambda expression
@@ -139,7 +131,7 @@ public class AstLambdaExpression extends SimpleNode {
}
Node secondChild = jjtGetChild(1);
if (secondChild instanceof AstLambdaExpression) {
- ((AstLambdaExpression) secondChild).setNestedState(nestedState);
+ ((AstLambdaExpression) secondChild).populateNestedState(lambdaExpressionNestedState);
}
}
}
@@ -155,28 +147,5 @@ public class AstLambdaExpression extends SimpleNode {
}
return result.toString();
}
-
-
- private static class NestedState {
-
- private int nestingCount = 0;
- private boolean hasFormalParameters = false;
-
- private void incrementNestingCount() {
- nestingCount++;
- }
-
- private int getNestingCount() {
- return nestingCount;
- }
-
- private void setHasFormalParameters() {
- hasFormalParameters = true;
- }
-
- private boolean getHasFormalParameters() {
- return hasFormalParameters;
- }
- }
}
/* JavaCC - OriginalChecksum=071159eff10c8e15ec612c765ae4480a (do not edit this line) */
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index c0f8af8471..4559821a27 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -114,6 +114,14 @@
</fix>
</changelog>
</subsection>
+ <subsection name="Jasper">
+ <changelog>
+ <fix>
+ <bug>66325</bug>: Fix concurrency issue in evaluation of expression
+ language containing lambda expressions. (markt)
+ </fix>
+ </changelog>
+ </subsection>
<subsection name="Other">
<changelog>
<update>
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