/*

 * 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.

 */

/*

 * @test

 * @bug 6199075

 *

 * @summary Unambiguous varargs method calls flagged as ambiguous

 * @author mcimadamore

 *

 */

import com.sun.source.util.JavacTask;

import com.sun.tools.classfile.Instruction;

import com.sun.tools.classfile.Attribute;

import com.sun.tools.classfile.ClassFile;

import com.sun.tools.classfile.Code_attribute;

import com.sun.tools.classfile.ConstantPool.*;

import com.sun.tools.classfile.Method;

import com.sun.tools.javac.api.JavacTool;

import com.sun.tools.javac.util.List;

import java.io.File;

import java.net.URI;

import java.util.Arrays;

import java.util.Locale;

import javax.tools.Diagnostic;

import javax.tools.JavaCompiler;

import javax.tools.JavaFileObject;

import javax.tools.SimpleJavaFileObject;

import javax.tools.StandardJavaFileManager;

import javax.tools.ToolProvider;

public class T6199075 {

    int checkCount = 0;

    int bytecodeCheckCount = 0;

    enum TypeKind {

        BYTE("byte", "(byte)1", "[B", 0),

        CHAR("char", "'c'", "[C", 1),

        SHORT("short", "(short)1", "[S", 2),

        INT("int", "1", "[I", 3),

        LONG("long", "1L", "[J", 4),

        FLOAT("float", "1.0F", "[F", 5),

        DOUBLE("double", "1.0D", "[D", 6),

        BOOLEAN("boolean", "true", "[Z", -1);

        String typeString;

        String valueString;

        String bytecodeString;

        private int subtypeTag;

        TypeKind(String typeString, String valueString, String bytecodeString, int subtypeTag) {

            this.typeString = typeString;

            this.valueString = valueString;

            this.bytecodeString = bytecodeString;

            this.subtypeTag = subtypeTag;

        }

        boolean isSubtypeOf(TypeKind that) {

            switch (this) {

                case BOOLEAN:

                    return that == BOOLEAN;

                case BYTE:

                case CHAR:

                    return this.subtypeTag == that.subtypeTag ||

                            this.subtypeTag + 2 <= that.subtypeTag;

                default:

                    return this.subtypeTag <= that.subtypeTag;

            }

        }

    }

    enum ArgumentsArity {

        ZERO(0),

        ONE(1),

        TWO(2),

        THREE(3);

        int arity;

        ArgumentsArity(int arity) {

            this.arity = arity;

        }

        String asExpressionList(TypeKind type) {

            StringBuilder buf = new StringBuilder();

            String sep = "";

            for (int i = 0; i < arity; i++) {

                buf.append(sep);

                buf.append(type.valueString);

                sep = ",";

            }

            return buf.toString();

        }

    }

    static class VarargsMethod {

        TypeKind varargsElement;

        VarargsMethod(TypeKind varargsElement) {

            this.varargsElement = varargsElement;

        }

        @Override

        public String toString() {

            return "void m("+ varargsElement.typeString+ "... args) {}";

        }

        boolean isApplicable(TypeKind actual, ArgumentsArity argsArity) {

            return argsArity == ArgumentsArity.ZERO ||

                    actual.isSubtypeOf(varargsElement);

        }

        boolean isMoreSpecificThan(VarargsMethod that) {

            return varargsElement.isSubtypeOf(that.varargsElement);

        }

    }

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

        new T6199075().test();

    }

    void test() throws Exception {

        try {

            for (TypeKind formal1 : TypeKind.values()) {

                VarargsMethod m1 = new VarargsMethod(formal1);

                for (TypeKind formal2 : TypeKind.values()) {

                    VarargsMethod m2 = new VarargsMethod(formal2);

                    for (TypeKind actual : TypeKind.values()) {

                        for (ArgumentsArity argsArity : ArgumentsArity.values()) {

                            compileAndCheck(m1, m2, actual, argsArity);

                        }

                    }

                }

            }

            System.out.println("Total checks made: " + checkCount);

            System.out.println("Bytecode checks made: " + bytecodeCheckCount);

        } finally {

            fm.close();

        }

    }

    // Create a single file manager and reuse it for each compile to save time.

    StandardJavaFileManager fm = JavacTool.create().getStandardFileManager(null, null, null);

    void compileAndCheck(VarargsMethod m1, VarargsMethod m2, TypeKind actual, ArgumentsArity argsArity) throws Exception {

        final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();

        JavaSource source = new JavaSource(m1, m2, actual, argsArity);

        ErrorChecker ec = new ErrorChecker();

        JavacTask ct = (JavacTask)tool.getTask(null, fm, ec,

                null, null, Arrays.asList(source));

        ct.generate();

        check(source, ec, m1, m2, actual, argsArity);

    }

    void check(JavaSource source, ErrorChecker ec, VarargsMethod m1, VarargsMethod m2, TypeKind actual, ArgumentsArity argsArity) {

        checkCount++;

        boolean resolutionError = false;

        VarargsMethod selectedMethod = null;

        boolean m1_applicable = m1.isApplicable(actual, argsArity);

        boolean m2_applicable = m2.isApplicable(actual, argsArity);

        if (!m1_applicable && !m2_applicable) {

            resolutionError = true;

        } else if (m1_applicable && m2_applicable) {

            //most specific

            boolean m1_moreSpecific = m1.isMoreSpecificThan(m2);

            boolean m2_moreSpecific = m2.isMoreSpecificThan(m1);

            resolutionError = m1_moreSpecific == m2_moreSpecific;

            selectedMethod = m1_moreSpecific ? m1 : m2;

        } else {

            selectedMethod = m1_applicable ?

                m1 : m2;

        }

        if (ec.errorFound != resolutionError) {

            throw new Error("invalid diagnostics for source:\n" +

                    source.getCharContent(true) +

                    "\nExpected resolution error: " + resolutionError +

                    "\nFound error: " + ec.errorFound +

                    "\nCompiler diagnostics:\n" + ec.printDiags());

        } else if (!resolutionError) {

            verifyBytecode(selectedMethod);

        }

    }

    void verifyBytecode(VarargsMethod selected) {

        bytecodeCheckCount++;

        File compiledTest = new File("Test.class");

        try {

            ClassFile cf = ClassFile.read(compiledTest);

            Method testMethod = null;

            for (Method m : cf.methods) {

                if (m.getName(cf.constant_pool).equals("test")) {

                    testMethod = m;

                    break;

                }

            }

            if (testMethod == null) {

                throw new Error("Test method not found");

            }

            Code_attribute ea = (Code_attribute)testMethod.attributes.get(Attribute.Code);

            if (testMethod == null) {

                throw new Error("Code attribute for test() method not found");

            }

            for (Instruction i : ea.getInstructions()) {

                if (i.getMnemonic().equals("invokevirtual")) {

                    int cp_entry = i.getUnsignedShort(1);

                    CONSTANT_Methodref_info methRef =

                            (CONSTANT_Methodref_info)cf.constant_pool.get(cp_entry);

                    String type = methRef.getNameAndTypeInfo().getType();

                    if (!type.contains(selected.varargsElement.bytecodeString)) {

                        throw new Error("Unexpected type method call: " + type);

                    }

                    break;

                }

            }

        } catch (Exception e) {

            e.printStackTrace();

            throw new Error("error reading " + compiledTest +": " + e);

        }

    }

    static class JavaSource extends SimpleJavaFileObject {

        static final String source_template = "class Test {\n" +

                "   #V1\n" +

                "   #V2\n" +

                "   void test() { m(#E); }\n" +

                "}";

        String source;

        public JavaSource(VarargsMethod m1, VarargsMethod m2, TypeKind actual, ArgumentsArity argsArity) {

            super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);

            source = source_template.replaceAll("#V1", m1.toString()).

                    replaceAll("#V2", m2.toString()).

                    replaceAll("#E", argsArity.asExpressionList(actual));

        }

        @Override

        public CharSequence getCharContent(boolean ignoreEncodingErrors) {

            return source;

        }

    }

    static class ErrorChecker implements javax.tools.DiagnosticListener<JavaFileObject> {

        boolean errorFound;

        List<String> errDiags = List.nil();

        public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

            if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {

                errDiags = errDiags.append(diagnostic.getMessage(Locale.getDefault()));

                errorFound = true;

            }

        }

        String printDiags() {

            StringBuilder buf = new StringBuilder();

            for (String s : errDiags) {

                buf.append(s);

                buf.append("\n");

            }

            return buf.toString();

        }

    }

}