src/jdk.dynalink/share/classes/jdk/dynalink/beans/AccessibleMembersLookup.java
changeset 47216 71c04702a3d5
parent 35407 204abe4d8cbc
child 50695 36ca515343e0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.dynalink/share/classes/jdk/dynalink/beans/AccessibleMembersLookup.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,263 @@
+/*
+ * Copyright (c) 2010, 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file, and Oracle licenses the original version of this file under the BSD
+ * license:
+ */
+/*
+   Copyright 2009-2013 Attila Szegedi
+
+   Licensed under both the Apache License, Version 2.0 (the "Apache License")
+   and the BSD License (the "BSD License"), with licensee being free to
+   choose either of the two at their discretion.
+
+   You may not use this file except in compliance with either the Apache
+   License or the BSD License.
+
+   If you choose to use this file in compliance with the Apache License, the
+   following notice applies to you:
+
+       You may obtain a copy of the Apache 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.
+
+   If you choose to use this file in compliance with the BSD License, the
+   following notice applies to you:
+
+       Redistribution and use in source and binary forms, with or without
+       modification, are permitted provided that the following conditions are
+       met:
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in the
+         documentation and/or other materials provided with the distribution.
+       * Neither the name of the copyright holder nor the names of
+         contributors may be used to endorse or promote products derived from
+         this software without specific prior written permission.
+
+       THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+       IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+       TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+       PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
+       BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package jdk.dynalink.beans;
+
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Utility class for discovering accessible methods and inner classes. Normally, a public member declared on a class is
+ * accessible (that is, it can be invoked from anywhere). However, this is not the case if the class itself is not
+ * public, or belongs to a restricted-access package. In that case, it is required to lookup a member in a publicly
+ * accessible superclass or implemented interface of the class, and use it instead of the member discovered on the
+ * class.
+ */
+class AccessibleMembersLookup {
+    private final Map<MethodSignature, Method> methods;
+    private final Set<Class<?>> innerClasses;
+    private final boolean instance;
+
+    /**
+     * Creates a mapping for all accessible methods and inner classes on a class.
+     *
+     * @param clazz the inspected class
+     * @param instance true to inspect instance methods, false to inspect static methods.
+     */
+    AccessibleMembersLookup(final Class<?> clazz, final boolean instance) {
+        this.methods = new HashMap<>();
+        this.innerClasses = new LinkedHashSet<>();
+        this.instance = instance;
+        lookupAccessibleMembers(clazz);
+    }
+
+    /**
+     * Returns an accessible method equivalent of a method.
+     *
+     * @param m the method whose accessible equivalent is requested.
+     * @return the accessible equivalent for the method (can be the same as the passed in method), or null if there is
+     * no accessible method equivalent.
+     */
+    Method getAccessibleMethod(final Method m) {
+        return m == null ? null : methods.get(new MethodSignature(m));
+    }
+
+    Collection<Method> getMethods() {
+        return methods.values();
+    }
+
+    Class<?>[] getInnerClasses() {
+        return innerClasses.toArray(new Class<?>[0]);
+    }
+
+    /**
+     * A helper class that represents a method signature - name and argument types.
+     */
+    static final class MethodSignature {
+        private final String name;
+        private final Class<?>[] args;
+
+        /**
+         * Creates a new method signature from arbitrary data.
+         *
+         * @param name the name of the method this signature represents.
+         * @param args the argument types of the method.
+         */
+        MethodSignature(final String name, final Class<?>[] args) {
+            this.name = name;
+            this.args = args;
+        }
+
+        /**
+         * Creates a signature for the given method.
+         *
+         * @param method the method for which a signature is created.
+         */
+        MethodSignature(final Method method) {
+            this(method.getName(), method.getParameterTypes());
+        }
+
+        /**
+         * Compares this object to another object
+         *
+         * @param o the other object
+         * @return true if the other object is also a method signature with the same name, same number of arguments, and
+         * same types of arguments.
+         */
+        @Override
+        public boolean equals(final Object o) {
+            if(o instanceof MethodSignature) {
+                final MethodSignature ms = (MethodSignature)o;
+                return ms.name.equals(name) && Arrays.equals(args, ms.args);
+            }
+            return false;
+        }
+
+        /**
+         * Returns a hash code, consistent with the overridden {@link #equals(Object)}.
+         */
+        @Override
+        public int hashCode() {
+            return name.hashCode() ^ Arrays.hashCode(args);
+        }
+
+        @Override
+        public String toString() {
+            final StringBuilder b = new StringBuilder();
+            b.append("[MethodSignature ").append(name).append('(');
+            if(args.length > 0) {
+                b.append(args[0].getCanonicalName());
+                for(int i = 1; i < args.length; ++i) {
+                    b.append(", ").append(args[i].getCanonicalName());
+                }
+            }
+            return b.append(")]").toString();
+        }
+    }
+
+    private void lookupAccessibleMembers(final Class<?> clazz) {
+        boolean searchSuperTypes;
+
+        if(!CheckRestrictedPackage.isRestrictedClass(clazz)) {
+            searchSuperTypes = false;
+            for(final Method method: clazz.getMethods()) {
+                final boolean isStatic = Modifier.isStatic(method.getModifiers());
+                if(instance != isStatic) {
+                    final MethodSignature sig = new MethodSignature(method);
+                    if(!methods.containsKey(sig)) {
+                        final Class<?> declaringClass = method.getDeclaringClass();
+                        if(declaringClass != clazz && CheckRestrictedPackage.isRestrictedClass(declaringClass)) {
+                            //Sometimes, the declaring class of a method (Method.getDeclaringClass())
+                            //retrieved through Class.getMethods() for a public class will be a
+                            //non-public superclass. For such a method, we need to find a method with
+                            //the same name and signature in a public superclass or implemented
+                            //interface.
+                            //This typically doesn't happen with classes emitted by a reasonably modern
+                            //javac, as it'll create synthetic delegator methods in all public
+                            //immediate subclasses of the non-public class. We have, however, observed
+                            //this in the wild with class files compiled with older javac that doesn't
+                            //generate the said synthetic delegators.
+                            searchSuperTypes = true;
+                        } else {
+                            // don't allow inherited static
+                            if (!isStatic || clazz == declaringClass) {
+                                methods.put(sig, method);
+                            }
+                        }
+                    }
+                }
+            }
+            for(final Class<?> innerClass: clazz.getClasses()) {
+                // Add both static and non-static classes, regardless of instance flag. StaticClassLinker will just
+                // expose non-static classes with explicit constructor outer class argument.
+                // NOTE: getting inner class objects through getClasses() does not resolve them, so if those classes
+                // were not yet loaded, they'll only get loaded in a non-resolved state; no static initializers for
+                // them will trigger just by doing this.
+                innerClasses.add(innerClass);
+            }
+        } else {
+            searchSuperTypes = true;
+        }
+
+        // don't need to search super types for static methods
+        if(instance && searchSuperTypes) {
+            // If we reach here, the class is either not public, or it is in a restricted package. Alternatively, it is
+            // public, but some of its methods claim that their declaring class is non-public. We'll try superclasses
+            // and implemented interfaces then looking for public ones.
+            final Class<?>[] interfaces = clazz.getInterfaces();
+            for(int i = 0; i < interfaces.length; i++) {
+                lookupAccessibleMembers(interfaces[i]);
+            }
+            final Class<?> superclass = clazz.getSuperclass();
+            if(superclass != null) {
+                lookupAccessibleMembers(superclass);
+            }
+        }
+    }
+}