1/*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package com.sun.xml.internal.bind.v2.runtime.reflect.opt;
27
28import java.io.InputStream;
29import java.util.logging.Level;
30import java.util.logging.Logger;
31
32import com.sun.xml.internal.bind.Util;
33import com.sun.xml.internal.bind.v2.bytecode.ClassTailor;
34
35/**
36 * @author Kohsuke Kawaguchi
37 */
38class AccessorInjector {
39
40    private static final Logger logger = Util.getClassLogger();
41
42    protected static final boolean noOptimize =
43        Util.getSystemProperty(ClassTailor.class.getName()+".noOptimize")!=null;
44
45    static {
46        if(noOptimize)
47            logger.info("The optimized code generation is disabled");
48    }
49
50    /**
51     * Loads the optimized class and returns it.
52     *
53     * @return null
54     *      if it fails for some reason.
55     */
56    public static Class<?> prepare(
57        Class beanClass, String templateClassName, String newClassName, String... replacements ) {
58
59        if(noOptimize)
60            return null;
61
62        try {
63            ClassLoader cl = SecureLoader.getClassClassLoader(beanClass);
64            if(cl==null)    return null;    // how do I inject classes to this "null" class loader? for now, back off.
65
66            Class c = Injector.find(cl,newClassName);
67            if (c==null) {
68                byte[] image = tailor(templateClassName,newClassName,replacements);
69                if (image==null) {
70                    return null;
71                }
72                c = Injector.inject(cl,newClassName,image);
73                if (c == null) {
74                    Injector.find(cl, newClassName);
75                }
76            }
77            return c;
78        } catch(SecurityException e) {
79            // we don't have enough permission to do this
80            logger.log(Level.INFO,"Unable to create an optimized TransducedAccessor ",e);
81            return null;
82        }
83    }
84
85
86    /**
87     * Customizes a class file by replacing constant pools.
88     *
89     * @param templateClassName
90     *      The resource that contains the template class file.
91     * @param replacements
92     *      A list of pair of strings that specify the substitution
93     *      {@code String[]{search_0, replace_0, search_1, replace_1, ..., search_n, replace_n }
94     *
95     *      The search strings found in the constant pool will be replaced by the corresponding
96     *      replacement string.
97     */
98    private static byte[] tailor( String templateClassName, String newClassName, String... replacements ) {
99        InputStream resource;
100        if(CLASS_LOADER!=null)
101            resource = CLASS_LOADER.getResourceAsStream(templateClassName+".class");
102        else
103            resource = ClassLoader.getSystemResourceAsStream(templateClassName+".class");
104        if(resource==null)
105            return null;
106
107        return ClassTailor.tailor(resource,templateClassName,newClassName,replacements);
108    }
109
110    private static final ClassLoader CLASS_LOADER = SecureLoader.getClassClassLoader(AccessorInjector.class);
111
112}
113