/*

 * Copyright (c) 2014, 2019, 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.

 *

 * 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.

 */

package org.graalvm.compiler.core.test;

import static java.lang.String.format;

import java.io.IOException;

import java.lang.reflect.Constructor;

import java.lang.reflect.Executable;

import java.lang.reflect.Method;

import java.util.Arrays;

import java.util.HashSet;

import java.util.Set;

import org.graalvm.compiler.options.OptionDescriptor;

import org.graalvm.compiler.options.OptionDescriptors;

import org.graalvm.compiler.options.OptionKey;

import org.graalvm.compiler.options.OptionsParser;

import org.graalvm.compiler.serviceprovider.GraalServices;

import org.junit.Test;

import org.objectweb.asm.ClassReader;

import org.objectweb.asm.ClassVisitor;

import org.objectweb.asm.Label;

import org.objectweb.asm.MethodVisitor;

import org.objectweb.asm.Opcodes;

import org.objectweb.asm.Type;

/**

 * Verifies a class declaring one or more {@linkplain OptionKey options} has a class initializer

 * that only initializes the option(s). This sanity check mitigates the possibility of an option

 * value being used before being set.

 */

public class OptionsVerifierTest {

    @Test

    public void verifyOptions() throws IOException {

        HashSet<Class<?>> checked = new HashSet<>();

        for (OptionDescriptors opts : OptionsParser.getOptionsLoader()) {

            for (OptionDescriptor desc : opts) {

                OptionsVerifier.checkClass(desc.getDeclaringClass(), desc, checked);

            }

        }

    }

    static final class OptionsVerifier extends ClassVisitor {

        public static void checkClass(Class<?> cls, OptionDescriptor option, Set<Class<?>> checked) throws IOException {

            if (!checked.contains(cls)) {

                checked.add(cls);

                Class<?> superclass = cls.getSuperclass();

                if (superclass != null && !superclass.equals(Object.class)) {

                    checkClass(superclass, option, checked);

                }

                GraalServices.getClassfileAsStream(cls);

                ClassReader cr = new ClassReader(GraalServices.getClassfileAsStream(cls));

                ClassVisitor cv = new OptionsVerifier(cls, option);

                cr.accept(cv, 0);

            }

        }

        /**

         * The option field context of the verification.

         */

        private final OptionDescriptor option;

        /**

         * The class in which {@link #option} is declared or a super-class of that class. This is

         * the class whose {@code <clinit>} method is being verified.

         */

        private final Class<?> cls;

        /**

         * Source file context for error reporting.

         */

        String sourceFile = null;

        /**

         * Line number for error reporting.

         */

        int lineNo = -1;

        final Class<?>[] boxingTypes = {Boolean.class, Byte.class, Short.class, Character.class, Integer.class, Float.class, Long.class, Double.class};

        private static Class<?> resolve(String name) {

            try {

                return Class.forName(name.replace('/', '.'));

            } catch (ClassNotFoundException e) {

                throw new InternalError(e);

            }

        }

        OptionsVerifier(Class<?> cls, OptionDescriptor desc) {

            super(Opcodes.ASM5);

            this.cls = cls;

            this.option = desc;

        }

        @Override

        public void visitSource(String source, String debug) {

            this.sourceFile = source;

        }

        void verify(boolean condition, String message) {

            if (!condition) {

                error(message);

            }

        }

        void error(String message) {

            String errorMessage = format(

                            "%s:%d: Illegal code in %s.<clinit> which may be executed when %s.%s is initialized:%n%n    %s%n%n" + "The recommended solution is to move " + option.getName() +

                                            " into a separate class (e.g., %s.Options).%n",

                            sourceFile, lineNo, cls.getSimpleName(), option.getDeclaringClass().getSimpleName(), option.getName(),

                            message, option.getDeclaringClass().getSimpleName());

            throw new InternalError(errorMessage);

        }

        @Override

        public MethodVisitor visitMethod(int access, String name, String d, String signature, String[] exceptions) {

            if (name.equals("<clinit>")) {

                return new MethodVisitor(Opcodes.ASM5) {

                    @Override

                    public void visitLineNumber(int line, Label start) {

                        lineNo = line;

                    }

                    @Override

                    public void visitFieldInsn(int opcode, String owner, String fieldName, String fieldDesc) {

                        if (opcode == Opcodes.PUTFIELD || opcode == Opcodes.PUTSTATIC) {

                            verify(resolve(owner).equals(option.getDeclaringClass()), format("store to field %s.%s", resolve(owner).getSimpleName(), fieldName));

                            verify(opcode != Opcodes.PUTFIELD, format("store to non-static field %s.%s", resolve(owner).getSimpleName(), fieldName));

                        }

                    }

                    private Executable resolveMethod(String owner, String methodName, String methodDesc) {

                        Class<?> declaringClass = resolve(owner);

                        if (methodName.equals("<init>")) {

                            for (Constructor<?> c : declaringClass.getDeclaredConstructors()) {

                                if (methodDesc.equals(Type.getConstructorDescriptor(c))) {

                                    return c;

                                }

                            }

                        } else {

                            Type[] argumentTypes = Type.getArgumentTypes(methodDesc);

                            for (Method m : declaringClass.getDeclaredMethods()) {

                                if (m.getName().equals(methodName)) {

                                    if (Arrays.equals(argumentTypes, Type.getArgumentTypes(m))) {

                                        if (Type.getReturnType(methodDesc).equals(Type.getReturnType(m))) {

                                            return m;

                                        }

                                    }

                                }

                            }

                        }

                        throw new NoSuchMethodError(declaringClass + "." + methodName + methodDesc);

                    }

                    /**

                     * Checks whether a given method is allowed to be called.

                     */

                    private boolean checkInvokeTarget(Executable method) {

                        Class<?> holder = method.getDeclaringClass();

                        if (method instanceof Constructor) {

                            if (OptionKey.class.isAssignableFrom(holder)) {

                                return true;

                            }

                        } else if (Arrays.asList(boxingTypes).contains(holder)) {

                            return method.getName().equals("valueOf");

                        } else if (method.getDeclaringClass().equals(Class.class)) {

                            return method.getName().equals("desiredAssertionStatus");

                        }

                        return false;

                    }

                    @Override

                    public void visitMethodInsn(int opcode, String owner, String methodName, String methodDesc, boolean itf) {

                        Executable callee = resolveMethod(owner, methodName, methodDesc);

                        verify(checkInvokeTarget(callee), "invocation of " + callee);

                    }

                };

            } else {

                return null;

            }

        }

    }

}