/*

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 * 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

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 */

/*

 * @test

 * @bug 8231827

 * @summary Ensure the LV table entries are generated for bindings

 * @modules jdk.jdeps/com.sun.tools.classfile

 * @compile -g --enable-preview -source ${jdk.version} LocalVariableTable.java

 * @run main/othervm --enable-preview LocalVariableTable

 */

import java.io.*;

import java.lang.annotation.*;

import java.util.*;

import com.sun.tools.classfile.*;

/*

 * The test checks that a LocalVariableTable attribute is generated for the

 * method bodies containing patterns, and checks that the expected

 * set of entries is found in the attribute.

 *

 * The test looks for test cases represented by nested classes whose

 * name begins with "Pattern".  Each such class contains a method

 * with patterns, and because the test is compiled

 * with -g, these methods should have a LocalVariableTable.  The set of

 * expected names in the LVT is provided in an annotation on the class for

 * the test case.

 */

//Copied from: test/langtools/tools/javac/lambda/LocalVariableTable.java

public class LocalVariableTable {

    public static void main(String... args) throws Exception {

        new LocalVariableTable().run();

    }

    void run() throws Exception {

        // the declared classes are returned in an unspecified order,

        // so for neatness, sort them by name before processing them

        Class<?>[] classes = getClass().getDeclaredClasses();

        Arrays.sort(classes, (c1, c2) -> c1.getName().compareTo(c2.getName()));

        for (Class<?> c : classes) {

            if (c.getSimpleName().startsWith("Pattern"))

                check(c);

        }

        if (errors > 0)

            throw new Exception(errors + " errors found");

    }

    /** Check an individual test case. */

    void check(Class<?> c) throws Exception {

        System.err.println("Checking " + c.getSimpleName());

        Expect expect = c.getAnnotation(Expect.class);

        if (expect == null) {

            error("@Expect not found for class " + c.getSimpleName());

            return;

        }

        ClassFile cf = ClassFile.read(getClass().getResource(c.getName() + ".class").openStream());

        Method m = getMethodByName(cf, c.getSimpleName().contains("Lambda") ? "lambda$" : "test");

        if (m == null) {

            error("test method not found");

            return;

        }

        Code_attribute code = (Code_attribute) m.attributes.get(Attribute.Code);

        if (code == null) {

            error("Code attribute not found");

            return;

        }

        LocalVariableTable_attribute lvt =

                (LocalVariableTable_attribute) code.attributes.get(Attribute.LocalVariableTable);

        if (lvt == null) {

            error("LocalVariableTable attribute not found");

            return;

        }

        Set<String> foundNames = new LinkedHashSet<>();

        for (LocalVariableTable_attribute.Entry e: lvt.local_variable_table) {

            foundNames.add(cf.constant_pool.getUTF8Value(e.name_index));

        }

        Set<String> expectNames = new LinkedHashSet<>(Arrays.asList(expect.value()));

        if (!foundNames.equals(expectNames)) {

            Set<String> foundOnly = new LinkedHashSet<>(foundNames);

            foundOnly.removeAll(expectNames);

            for (String s: foundOnly)

                error("Unexpected name found: " + s);

            Set<String> expectOnly = new LinkedHashSet<>(expectNames);

            expectOnly.removeAll(foundNames);

            for (String s: expectOnly)

                error("Expected name not found: " + s);

        }

    }

    Method getMethodByName(ClassFile cf, String name) throws ConstantPoolException {

        for (Method m: cf.methods) {

            if (m.getName(cf.constant_pool).startsWith(name))

                return m;

        }

        return null;

    }

    /** Report an error. */

    void error(String msg) {

        System.err.println("Error: " + msg);

        errors++;

    }

    int errors;

    /**

     * Annotation used to provide the set of names expected in the LVT attribute.

     */

    @Retention(RetentionPolicy.RUNTIME)

    @interface Expect {

        String[] value();

    }

    /*

     * ---------- Test cases ---------------------------------------------------

     */

    @Expect({ "o", "s" })

    static class Pattern_Simple {

        public static void test(Object o) {

            if (o instanceof String s) {}

        }

    }

    @Expect({ "s" })

    static class Pattern_Lambda {

        public static void test(Object o) {

            if (o instanceof String s) {

                Runnable r = () -> {

                    s.length();

                };

            }

        }

    }

}