nashorn/src/jdk.dynalink/share/classes/jdk/dynalink/beans/ClassString.java
changeset 34447 ec4c069f9436
parent 33341 cc9fa3638714
child 42238 4d6b6b542dde
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/src/jdk.dynalink/share/classes/jdk/dynalink/beans/ClassString.java	Tue Nov 24 10:19:34 2015 +0100
@@ -0,0 +1,225 @@
+/*
+ * Copyright (c) 2010, 2013, 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.invoke.MethodHandle;
+import java.lang.invoke.MethodType;
+import java.security.AccessControlContext;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.LinkedList;
+import java.util.List;
+import jdk.dynalink.internal.AccessControlContextFactory;
+import jdk.dynalink.internal.InternalTypeUtilities;
+import jdk.dynalink.linker.LinkerServices;
+import jdk.dynalink.linker.support.TypeUtilities;
+
+/**
+ * Represents a sequence of {@link Class} objects, useful for representing method signatures. Provides value
+ * semantics for using them as map keys, as well as specificity calculations and applicability checks as per
+ * JLS.
+ */
+final class ClassString {
+    private static final AccessControlContext GET_CLASS_LOADER_CONTEXT =
+            AccessControlContextFactory.createAccessControlContext("getClassLoader");
+
+    /**
+     * An anonymous inner class used solely to represent the "type" of null values for method applicability checking.
+     */
+    static final Class<?> NULL_CLASS = (new Object() { /* Intentionally empty */ }).getClass();
+
+    private final Class<?>[] classes;
+    private int hashCode;
+
+    ClassString(final Class<?>[] classes) {
+        this.classes = classes;
+    }
+
+    ClassString(final MethodType type) {
+        this(type.parameterArray());
+    }
+
+    @Override
+    public boolean equals(final Object other) {
+        if(!(other instanceof ClassString)) {
+            return false;
+        }
+        final Class<?>[] otherClasses = ((ClassString)other).classes;
+        if(otherClasses.length != classes.length) {
+            return false;
+        }
+        for(int i = 0; i < otherClasses.length; ++i) {
+            if(otherClasses[i] != classes[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        if(hashCode == 0) {
+            int h = 0;
+            for(int i = 0; i < classes.length; ++i) {
+                h ^= classes[i].hashCode();
+            }
+            hashCode = h;
+        }
+        return hashCode;
+    }
+
+    boolean isVisibleFrom(final ClassLoader classLoader) {
+        return AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
+            @Override
+            public Boolean run() {
+                for(final Class<?> clazz: classes) {
+                    if(!InternalTypeUtilities.canReferenceDirectly(classLoader, clazz.getClassLoader())) {
+                        return false;
+                    }
+                }
+                return true;
+            }
+        }, GET_CLASS_LOADER_CONTEXT);
+    }
+
+    List<MethodHandle> getMaximallySpecifics(final List<MethodHandle> methods, final LinkerServices linkerServices, final boolean varArg) {
+        return MaximallySpecific.getMaximallySpecificMethodHandles(getApplicables(methods, linkerServices, varArg),
+                varArg, classes, linkerServices);
+    }
+
+    /**
+     * Returns all methods that are applicable to actual parameter classes represented by this ClassString object.
+     */
+    LinkedList<MethodHandle> getApplicables(final List<MethodHandle> methods, final LinkerServices linkerServices, final boolean varArg) {
+        final LinkedList<MethodHandle> list = new LinkedList<>();
+        for(final MethodHandle member: methods) {
+            if(isApplicable(member, linkerServices, varArg)) {
+                list.add(member);
+            }
+        }
+        return list;
+    }
+
+    /**
+     * Returns true if the supplied method is applicable to actual parameter classes represented by this ClassString
+     * object.
+     *
+     */
+    private boolean isApplicable(final MethodHandle method, final LinkerServices linkerServices, final boolean varArg) {
+        final Class<?>[] formalTypes = method.type().parameterArray();
+        final int cl = classes.length;
+        final int fl = formalTypes.length - (varArg ? 1 : 0);
+        if(varArg) {
+            if(cl < fl) {
+                return false;
+            }
+        } else {
+            if(cl != fl) {
+                return false;
+            }
+        }
+        // Starting from 1 as we ignore the receiver type
+        for(int i = 1; i < fl; ++i) {
+            if(!canConvert(linkerServices, classes[i], formalTypes[i])) {
+                return false;
+            }
+        }
+        if(varArg) {
+            final Class<?> varArgType = formalTypes[fl].getComponentType();
+            for(int i = fl; i < cl; ++i) {
+                if(!canConvert(linkerServices, classes[i], varArgType)) {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private static boolean canConvert(final LinkerServices ls, final Class<?> from, final Class<?> to) {
+        if(from == NULL_CLASS) {
+            return !to.isPrimitive();
+        }
+        return ls == null ? TypeUtilities.isMethodInvocationConvertible(from, to) : ls.canConvert(from, to);
+    }
+}