Merge pull request orphan-oss#88 from JCgH4164838Gh792C124B5/localOGN…

…L_3_2_FP_PR69_74_75

Forward-port PR#69, PR#74 and PR#75 together from 3.1.x to 3.2.x (cherry-pick)

pom.xml

@@ -75,6 +75,7 @@
     <build>
         <plugins>
             <plugin>
+                <!-- Source/target levels are at 1.7 (Travis CI now rejects 1.5) -->
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.0</version>

src/main/java/ognl/AccessibleObjectHandler.java

@@ -0,0 +1,39 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * and/or LICENSE 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 ognl;
+
+import java.lang.reflect.AccessibleObject;
+
+/**
+ * This interface provides a mechanism for indirect reflection access processing
+ *   of AccessibleObject instances by OGNL.  It can be used to provide different
+ *   behaviour as JDK reflection mechanisms evolve.
+ *
+ * @since 3.1.24
+ */
+public abstract interface AccessibleObjectHandler
+{
+    /**
+     * Provides an appropriate implementation to change the accessibility of accessibleObject.
+     *
+     * @param accessibleObject
+     * @param flag
+     */
+    void setAccessible(AccessibleObject accessibleObject, boolean flag);
+}

src/main/java/ognl/AccessibleObjectHandlerJDK9Plus.java

@@ -0,0 +1,245 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * and/or LICENSE 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 ognl;
+
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+/**
+ * Utilizes a JDK 9 and later mechanism for changing the accessibility level of a given
+ *   AccessibleObject.
+ *
+ * If the JDK 9+ mechanism fails, this class will fall back to a standard pre-JDK 9 reflection mechanism.
+ *   Note:  That may cause "WARNING: Illegal reflective access" output to be generated to stdout/stderr.
+ *
+ * For reference, this class draws on information from the following locations:
+ *   - Post about Illegal Reflective Access <a href="https://stackoverflow.com/questions/50251798/what-is-an-illegal-reflective-access">what is an illegal reflective access</a>
+ *   - Blog on Unsafe <a href="http://mishadoff.com/blog/java-magic-part-4-sun-dot-misc-dot-unsafe/">Java Magic. Part 4: sun.misc.Unsafe</a>
+ *   - Blog on Unsafe <a href="https://www.baeldung.com/java-unsafe">Guide to sun.misc.Unsafe</a>
+ *   - JEP about access to Unsafe being retained in JDK 9 <a href="https://openjdk.java.net/jeps/260">JEP 260: Encapsulate Most Internal APIs</a>
+ *
+ * In addition to the above, inspiration was drawn from Gson: <a href="https://github.com/google/gson/pull/1218">PR 1218</a>,
+ *   <a href="https://github.com/google/gson/pull/1306">PR 1306</a>.
+ *
+ * Appreciation and credit to the authors, contributors and commenters for the information contained in the preceding links.
+ *
+ * @since 3.1.24
+ */
+class AccessibleObjectHandlerJDK9Plus implements AccessibleObjectHandler
+{
+    private static final Class _clazzUnsafe = instantiateClazzUnsafe();
+    private static final Object _unsafeInstance = instantiateUnsafeInstance(_clazzUnsafe);
+    private static final Method _unsafeObjectFieldOffsetMethod = instantiateUnsafeObjectFieldOffsetMethod(_clazzUnsafe);
+    private static final Method _unsafePutBooleanMethod = instantiateUnsafePutBooleanMethod(_clazzUnsafe);
+    private static final Field _accessibleObjectOverrideField = instantiateAccessibleObjectOverrideField();
+    private static final long _accessibleObjectOverrideFieldOffset = determineAccessibleObjectOverrideFieldOffset();
+
+    /**
+     * Private constructor
+     */
+    private AccessibleObjectHandlerJDK9Plus() {}
+
+    /**
+     * Package-accessible method to determine if a given class is Unsafe or a descendant
+     *   of Unsafe.
+     *
+     * @param clazz
+     * @return true if parameter is Unsafe or a descendant, false otherwise
+     */
+    static boolean unsafeOrDescendant(final Class clazz) {
+        return (_clazzUnsafe != null ? _clazzUnsafe.isAssignableFrom(clazz) : false);
+    }
+
+    /**
+     * Instantiate an instance of the Unsafe class.
+     *
+     * @return class if available, null otherwise
+     */
+    private static Class instantiateClazzUnsafe() {
+        Class clazz;
+
+        try {
+            clazz = Class.forName("sun.misc.Unsafe");
+        } catch (Throwable t) {
+            clazz = null;
+        }
+
+        return clazz;
+    }
+
+    /**
+     * Instantiate an instance of Unsafe object.
+     *
+     * @param clazz (expected to be an Unsafe instance)
+     * @return instance if available, null otherwise
+     */
+    private static Object instantiateUnsafeInstance(Class clazz) {
+        Object unsafe;
+
+        if (clazz != null) {
+            Field field = null;
+            try {
+                field = clazz.getDeclaredField("theUnsafe");
+                field.setAccessible(true);
+                unsafe = field.get(null);
+            } catch (Throwable t) {
+                unsafe = null;
+            } finally {
+                if (field != null) {
+                    try {
+                        field.setAccessible(false);
+                    } catch (Throwable t) {
+                        // Don't care
+                    }
+                }
+            }
+        } else {
+            unsafe = null;
+        }
+
+        return unsafe;
+    }
+
+    /**
+     * Instantiate an Unsafe.objectFieldOffset() method instance.
+     *
+     * @param clazz (expected to be an Unsafe instance)
+     * @return method if available, null otherwise
+     */
+    private static Method instantiateUnsafeObjectFieldOffsetMethod(Class clazz) {
+        Method method;
+
+        if (clazz != null) {
+            try {
+                method = clazz.getMethod("objectFieldOffset", Field.class);
+            } catch (Throwable t) {
+                method = null;
+            }
+        } else {
+            method = null;
+        }
+
+        return method;
+    }
+
+    /**
+     * Instantiate an Unsafe.putBoolean() method instance.
+     *
+     * @param clazz (expected to be an Unsafe instance)
+     * @return method if available, null otherwise
+     */
+    private static Method instantiateUnsafePutBooleanMethod(Class clazz) {
+        Method method;
+
+        if (clazz != null) {
+            try {
+                method = clazz.getMethod("putBoolean", Object.class, long.class, boolean.class);
+            } catch (Throwable t) {
+                method = null;
+            }
+        } else {
+            method = null;
+        }
+
+        return method;
+    }
+
+    /**
+     * Instantiate an AccessibleObject override field instance.
+     *
+     * @return field if available, null otherwise
+     */
+    private static Field instantiateAccessibleObjectOverrideField() {
+        Field field;
+
+        try {
+            field = AccessibleObject.class.getDeclaredField("override");
+        } catch (Throwable t) {
+            field = null;
+        }
+
+        return field;
+    }
+
+    /**
+     * Attempt to determined the AccessibleObject override field offset.
+     *
+     * @return field offset if available, -1 otherwise
+     */
+    private static long determineAccessibleObjectOverrideFieldOffset() {
+        long offset = -1;
+
+        if (_accessibleObjectOverrideField != null && _unsafeObjectFieldOffsetMethod != null && _unsafeInstance != null) {
+            try {
+                offset = (Long) _unsafeObjectFieldOffsetMethod.invoke(_unsafeInstance, _accessibleObjectOverrideField);
+            } catch (Throwable t) {
+                // Don't care (offset already -1)
+            }
+        }
+
+        return offset;
+    }
+
+    /**
+     * Package-level generator of an AccessibleObjectHandlerJDK9Plus instance.
+     *
+     * Not intended for use outside of the package.
+     *
+     * Note: An AccessibleObjectHandlerJDK9Plus will only be created if running on a
+     *   JDK9+ and the environment flag is set.  Otherwise this method will return
+     *   an AccessibleHandlerPreJDK9 instance instead,
+     *
+     * @return an AccessibleObjectHandler instance
+     *
+     * @since 3.1.24
+     */
+    static AccessibleObjectHandler createHandler() {
+        if (OgnlRuntime.usingJDK9PlusAccessHandler()){
+            return new AccessibleObjectHandlerJDK9Plus();
+        } else {
+            return AccessibleObjectHandlerPreJDK9.createHandler();
+        }
+    }
+
+    /**
+     * Utilize accessibility modification mechanism for JDK 9 (Java Major Version 9) and later.
+     *   Should that mechanism fail, attempt a standard pre-JDK9 accessibility modification.
+     *
+     * @param accessibleObject
+     * @param flag
+     */
+    public void setAccessible(AccessibleObject accessibleObject, boolean flag) {
+        boolean operationComplete = false;
+
+        if (_unsafeInstance != null && _unsafePutBooleanMethod != null && _accessibleObjectOverrideFieldOffset != -1) {
+            try {
+                _unsafePutBooleanMethod.invoke(_unsafeInstance, accessibleObject, _accessibleObjectOverrideFieldOffset, flag);
+                operationComplete = true;
+            } catch (Throwable t) {
+                // Don't care (operationComplete already false)
+            }
+        }
+        if (!operationComplete) {
+            // Fallback to standard reflection if Unsafe processing fails
+            accessibleObject.setAccessible(flag);
+        }
+    }
+
+}

src/main/java/ognl/AccessibleObjectHandlerPreJDK9.java

@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * and/or LICENSE 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 ognl;
+
+import java.lang.reflect.AccessibleObject;
+
+/**
+ * Utilizes a standard pre-JDK 9 reflection mechanism for changing the accessibility level of
+ *   a given AccessibleObject.
+ *
+ * @since 3.1.24
+ */
+class AccessibleObjectHandlerPreJDK9 implements AccessibleObjectHandler
+{
+
+    /**
+     * Private constructor
+     */
+    private AccessibleObjectHandlerPreJDK9() {}
+
+    /**
+     * Package-level generator of an AccessibleObjectHandlerJDK9Plus instance.
+     *
+     * Not intended for use outside of the package.
+     *
+     * @return an AccessibleObjectHandler instance
+     *
+     * @since 3.1.24
+     */
+    static AccessibleObjectHandler createHandler() {
+        return new AccessibleObjectHandlerPreJDK9();
+    }
+
+    /**
+     * Utilize accessibility modification mechanism for JDK 8 (Java Major Version 8) and earlier.
+     *   It is also the default modification mechanism for JDK 9+.
+     *
+     * @param accessibleObject
+     * @param flag
+     */
+    public void setAccessible(AccessibleObject accessibleObject, boolean flag) {
+        accessibleObject.setAccessible(flag);
+    }
+
+}