/*
 * Copyright (c) 1999, 2018, 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.
 */

package com.sun.tools.javac.jvm;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.tools.FileObject;
import javax.tools.JavaFileManager;
import javax.tools.JavaFileManager.Location;
import javax.tools.StandardLocation;

import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.ModuleSymbol;
import com.sun.tools.javac.code.Symbol.VarSymbol;
import com.sun.tools.javac.code.Symtab;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Types;
import com.sun.tools.javac.model.JavacElements;
import com.sun.tools.javac.util.Assert;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.Log;
import com.sun.tools.javac.util.Options;
import com.sun.tools.javac.util.Pair;

import static com.sun.tools.javac.main.Option.*;
import static com.sun.tools.javac.code.Kinds.Kind.*;
import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;

This class provides operations to write native header files for classes.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/** This class provides operations to write native header files for classes.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class JNIWriter {
    protected static final Context.Key<JNIWriter> jniWriterKey = new Context.Key<>();

    
Access to files. /** Access to files. */
    private final JavaFileManager fileManager;

    Types      types;
    Symtab     syms;

    
The log to use for verbose output.
/** The log to use for verbose output.
     */
    private final Log log;

    
Switch: verbose output.
/** Switch: verbose output.
     */
    private boolean verbose;

    
Switch: check all nested classes of top level class
/** Switch: check all nested classes of top level class
     */
    private boolean checkAll;

    
If true, class files will be written in module-specific subdirectories
of the NATIVE_HEADER_OUTPUT location.
/**
     * If true, class files will be written in module-specific subdirectories
     * of the NATIVE_HEADER_OUTPUT location.
     */
    public boolean multiModuleMode;

    private Context context;

    private static final boolean isWindows =
        System.getProperty("os.name").startsWith("Windows");

    
Get the ClassWriter instance for this context. /** Get the ClassWriter instance for this context. */
    public static JNIWriter instance(Context context) {
        JNIWriter instance = context.get(jniWriterKey);
        if (instance == null)
            instance = new JNIWriter(context);
        return instance;
    }

    
Construct a class writer, given an options table.
/** Construct a class writer, given an options table.
     */
    private JNIWriter(Context context) {
        context.put(jniWriterKey, this);
        fileManager = context.get(JavaFileManager.class);
        log = Log.instance(context);

        Options options = Options.instance(context);
        verbose = options.isSet(VERBOSE);
        checkAll = options.isSet("javah:full");

        this.context = context; // for lazyInit()
    }

    private void lazyInit() {
        if (types == null)
            types = Types.instance(context);
        if (syms == null)
            syms = Symtab.instance(context);

    }

    static boolean isSynthetic(Symbol s) {
        return hasFlag(s, Flags.SYNTHETIC);
    }
    static boolean isStatic(Symbol s) {
        return hasFlag(s, Flags.STATIC);
    }
    static boolean isFinal(Symbol s) {
        return hasFlag(s, Flags.FINAL);
    }
    static boolean isNative(Symbol s) {
        return hasFlag(s, Flags.NATIVE);
    }
    static private boolean hasFlag(Symbol m, int flag) {
        return (m.flags() & flag) != 0;
    }

    public boolean needsHeader(ClassSymbol c) {
        lazyInit();
        if (c.isLocal() || isSynthetic(c))
            return false;
        return (checkAll)
                ? needsHeader(c.outermostClass(), true)
                : needsHeader(c, false);
    }

    private boolean needsHeader(ClassSymbol c, boolean checkNestedClasses) {
        if (c.isLocal() || isSynthetic(c))
            return false;

        for (Symbol sym : c.members_field.getSymbols(NON_RECURSIVE)) {
            if (sym.kind == MTH && isNative(sym))
                return true;
            for (Attribute.Compound a: sym.getDeclarationAttributes()) {
                if (a.type.tsym == syms.nativeHeaderType.tsym)
                    return true;
            }
        }
        if (checkNestedClasses) {
            for (Symbol sym : c.members_field.getSymbols(NON_RECURSIVE)) {
                if ((sym.kind == TYP) && needsHeader(((ClassSymbol) sym), true))
                    return true;
            }
        }
        return false;
    }

    
Emit a class file for a given class.
 @param c      The class from which a class file is generated.
/** Emit a class file for a given class.
     *  @param c      The class from which a class file is generated.
     */
    public FileObject write(ClassSymbol c) throws IOException {
        String className = c.flatName().toString();
        Location outLocn;
        if (multiModuleMode) {
            ModuleSymbol msym = c.owner.kind == MDL ? (ModuleSymbol) c.owner : c.packge().modle;
            outLocn = fileManager.getLocationForModule(StandardLocation.NATIVE_HEADER_OUTPUT, msym.name.toString());
        } else {
            outLocn = StandardLocation.NATIVE_HEADER_OUTPUT;
        }
        FileObject outFile
            = fileManager.getFileForOutput(outLocn,
                "", className.replaceAll("[.$]", "_") + ".h", null);
        PrintWriter out = new PrintWriter(outFile.openWriter());
        try {
            write(out, c);
            if (verbose)
                log.printVerbose("wrote.file", outFile.getName());
            out.close();
            out = null;
        } finally {
            if (out != null) {
                // if we are propogating an exception, delete the file
                out.close();
                outFile.delete();
                outFile = null;
            }
        }
        return outFile; // may be null if write failed
    }

    public void write(PrintWriter out, ClassSymbol sym) throws IOException {
        lazyInit();
        try {
            String cname = encode(sym.fullname, EncoderType.CLASS);
            fileTop(out);
            includes(out);
            guardBegin(out, cname);
            cppGuardBegin(out);

            writeStatics(out, sym);
            writeMethods(out, sym, cname);

            cppGuardEnd(out);
            guardEnd(out);
        } catch (TypeSignature.SignatureException e) {
            throw new IOException(e);
        }
    }
    protected void writeStatics(PrintWriter out, ClassSymbol sym) throws IOException {
        List<ClassSymbol> clist = new ArrayList<>();
        for (ClassSymbol cd = sym; cd != null;
                cd = (ClassSymbol) cd.getSuperclass().tsym) {
            clist.add(cd);
        }
        /*
         * list needs to be super-class, base-class1, base-class2 and so on,
         * so we reverse class hierarchy
         */
        Collections.reverse(clist);
        for (ClassSymbol cd : clist) {
            for (Symbol i : cd.getEnclosedElements()) {
                // consider only final, static and fields with ConstantExpressions
                if (isFinal(i) && i.isStatic() && i.kind == VAR) {
                    VarSymbol v = (VarSymbol) i;
                    if (v.getConstantValue() != null) {
                        Pair<ClassSymbol, VarSymbol> p = new Pair<>(sym, v);
                        printStaticDefines(out, p);
                    }
                }
            }
        }
    }
    static void printStaticDefines(PrintWriter out, Pair<ClassSymbol, VarSymbol> p) {
        ClassSymbol cls = p.fst;
        VarSymbol f = p.snd;
        Object value = f.getConstantValue();
        String valueStr = null;
        switch (f.asType().getKind()) {
            case BOOLEAN:
                valueStr = (((Boolean) value) ? "1L" : "0L");
                break;
            case BYTE: case SHORT: case INT:
                valueStr = value.toString() + "L";
                break;
            case LONG:
                // Visual C++ supports the i64 suffix, not LL.
                valueStr = value.toString() + ((isWindows) ? "i64" : "LL");
                break;
            case CHAR:
                Character ch = (Character) value;
                valueStr = String.valueOf(((int) ch) & 0xffff) + "L";
                break;
            case FLOAT:
                // bug compatible
                float fv = ((Float) value).floatValue();
                valueStr = (Float.isInfinite(fv))
                        ? ((fv < 0) ? "-" : "") + "Inff"
                        : value.toString() + "f";
                break;
            case DOUBLE:
                // bug compatible
                double d = ((Double) value).doubleValue();
                valueStr = (Double.isInfinite(d))
                        ? ((d < 0) ? "-" : "") + "InfD"
                        : value.toString();
                break;
            default:
                valueStr = null;
        }
        if (valueStr != null) {
            out.print("#undef ");
            String cname = encode(cls.getQualifiedName(), EncoderType.CLASS);
            String fname = encode(f.getSimpleName(), EncoderType.FIELDSTUB);
            out.println(cname + "_" + fname);
            out.print("#define " + cname + "_");
            out.println(fname + " " + valueStr);
        }
    }
    protected void writeMethods(PrintWriter out, ClassSymbol sym, String cname)
            throws IOException, TypeSignature.SignatureException {
        List<Symbol> classmethods = sym.getEnclosedElements();
        for (Symbol md : classmethods) {
            if (isNative(md)) {
                TypeSignature newtypesig = new TypeSignature(types);
                CharSequence methodName = md.getSimpleName();
                boolean isOverloaded = false;
                for (Symbol md2 : classmethods) {
                    if ((md2 != md)
                            && (methodName.equals(md2.getSimpleName()))
                            && isNative(md2)) {
                        isOverloaded = true;
                    }
                }
                out.println("/*");
                out.println(" * Class:     " + cname);
                out.println(" * Method:    " + encode(methodName, EncoderType.FIELDSTUB));
                out.println(" * Signature: " + newtypesig.getSignature(md.type));
                out.println(" */");
                out.println("JNIEXPORT " + jniType(types.erasure(md.type.getReturnType()))
                        + " JNICALL " + encodeMethod(md, sym, isOverloaded));
                out.print("  (JNIEnv *, ");
                out.print((md.isStatic())
                        ? "jclass"
                        : "jobject");
                for (Type arg : types.erasure(md.type.getParameterTypes())) {
                    out.print(", ");
                    out.print(jniType(arg));
                }
                out.println(");");
                out.println();
            }
        }
    }
    @SuppressWarnings("fallthrough")
    protected final String jniType(Type t) {
        switch (t.getKind()) {
            case ARRAY: {
                Type ct = ((Type.ArrayType)t).getComponentType();
                switch (ct.getKind()) {
                    case BOOLEAN:  return "jbooleanArray";
                    case BYTE:     return "jbyteArray";
                    case CHAR:     return "jcharArray";
                    case SHORT:    return "jshortArray";
                    case INT:      return "jintArray";
                    case LONG:     return "jlongArray";
                    case FLOAT:    return "jfloatArray";
                    case DOUBLE:   return "jdoubleArray";
                    case ARRAY:
                    case DECLARED: return "jobjectArray";
                    default: throw new Error(ct.toString());
                }
            }

            case VOID:     return "void";
            case BOOLEAN:  return "jboolean";
            case BYTE:     return "jbyte";
            case CHAR:     return "jchar";
            case SHORT:    return "jshort";
            case INT:      return "jint";
            case LONG:     return "jlong";
            case FLOAT:    return "jfloat";
            case DOUBLE:   return "jdouble";
            case DECLARED: {
                if (t.tsym.type == syms.stringType) {
                    return "jstring";
                } else if (types.isAssignable(t, syms.throwableType)) {
                    return "jthrowable";
                } else if (types.isAssignable(t, syms.classType)) {
                    return "jclass";
                } else {
                    return "jobject";
                }
            }
        }

        Assert.check(false, "jni unknown type");
        return null; /* dead code. */
    }

    protected void  fileTop(PrintWriter out) {
        out.println("/* DO NOT EDIT THIS FILE - it is machine generated */");
    }

    protected void includes(PrintWriter out) {
        out.println("#include <jni.h>");
    }

    /*
     * Deal with the C pre-processor.
     */
    protected void cppGuardBegin(PrintWriter out) {
        out.println("#ifdef __cplusplus");
        out.println("extern \"C\" {");
        out.println("#endif");
    }

    protected void cppGuardEnd(PrintWriter out) {
        out.println("#ifdef __cplusplus");
        out.println("}");
        out.println("#endif");
    }

    protected void guardBegin(PrintWriter out, String cname) {
        out.println("/* Header for class " + cname + " */");
        out.println();
        out.println("#ifndef _Included_" + cname);
        out.println("#define _Included_" + cname);
    }

    protected void guardEnd(PrintWriter out) {
        out.println("#endif");
    }

    String encodeMethod(Symbol msym, ClassSymbol clazz,
            boolean isOverloaded) throws TypeSignature.SignatureException {
        StringBuilder result = new StringBuilder(100);
        result.append("Java_");
        /* JNI */
        result.append(encode(clazz.flatname.toString(), EncoderType.JNI));
        result.append('_');
        result.append(encode(msym.getSimpleName(), EncoderType.JNI));
        if (isOverloaded) {
            TypeSignature typeSig = new TypeSignature(types);
            StringBuilder sig = typeSig.getParameterSignature(msym.type);
            result.append("__").append(encode(sig, EncoderType.JNI));
        }
        return result.toString();
    }

    static enum EncoderType {
        CLASS,
        FIELDSTUB,
        FIELD,
        JNI,
        SIGNATURE
    }
    @SuppressWarnings("fallthrough")
    static String encode(CharSequence name, EncoderType mtype) {
        StringBuilder result = new StringBuilder(100);
        int length = name.length();

        for (int i = 0; i < length; i++) {
            char ch = name.charAt(i);
            if (isalnum(ch)) {
                result.append(ch);
                continue;
            }
            switch (mtype) {
                case CLASS:
                    switch (ch) {
                        case '.':
                        case '_':
                            result.append("_");
                            break;
                        case '$':
                            result.append("__");
                            break;
                        default:
                            result.append(encodeChar(ch));
                    }
                    break;
                case JNI:
                    switch (ch) {
                        case '/':
                        case '.':
                            result.append("_");
                            break;
                        case '_':
                            result.append("_1");
                            break;
                        case ';':
                            result.append("_2");
                            break;
                        case '[':
                            result.append("_3");
                            break;
                        default:
                            result.append(encodeChar(ch));
                    }
                    break;
                case SIGNATURE:
                    result.append(isprint(ch) ? ch : encodeChar(ch));
                    break;
                case FIELDSTUB:
                    result.append(ch == '_' ? ch : encodeChar(ch));
                    break;
                default:
                    result.append(encodeChar(ch));
            }
        }
        return result.toString();
    }

    static String encodeChar(char ch) {
        String s = Integer.toHexString(ch);
        int nzeros = 5 - s.length();
        char[] result = new char[6];
        result[0] = '_';
        for (int i = 1; i <= nzeros; i++) {
            result[i] = '0';
        }
        for (int i = nzeros + 1, j = 0; i < 6; i++, j++) {
            result[i] = s.charAt(j);
        }
        return new String(result);
    }

    /* Warning: Intentional ASCII operation. */
    private static boolean isalnum(char ch) {
        return ch <= 0x7f && /* quick test */
                ((ch >= 'A' && ch <= 'Z')  ||
                 (ch >= 'a' && ch <= 'z')  ||
                 (ch >= '0' && ch <= '9'));
    }

    /* Warning: Intentional ASCII operation. */
    private static boolean isprint(char ch) {
        return ch >= 32 && ch <= 126;
    }

    private static class TypeSignature {
        static class SignatureException extends Exception {
            private static final long serialVersionUID = 1L;
            SignatureException(String reason) {
                super(reason);
            }
        }

        JavacElements elems;
        Types    types;

        /* Signature Characters */
        private static final String SIG_VOID                   = "V";
        private static final String SIG_BOOLEAN                = "Z";
        private static final String SIG_BYTE                   = "B";
        private static final String SIG_CHAR                   = "C";
        private static final String SIG_SHORT                  = "S";
        private static final String SIG_INT                    = "I";
        private static final String SIG_LONG                   = "J";
        private static final String SIG_FLOAT                  = "F";
        private static final String SIG_DOUBLE                 = "D";
        private static final String SIG_ARRAY                  = "[";
        private static final String SIG_CLASS                  = "L";

        public TypeSignature(Types types) {
            this.types = types;
        }

        StringBuilder getParameterSignature(Type mType)
                throws SignatureException {
            StringBuilder result = new StringBuilder();
            for (Type pType : mType.getParameterTypes()) {
                result.append(getJvmSignature(pType));
            }
            return result;
        }

        StringBuilder getReturnSignature(Type mType)
                throws SignatureException {
            return getJvmSignature(mType.getReturnType());
        }

        StringBuilder getSignature(Type mType) throws SignatureException {
            StringBuilder sb = new StringBuilder();
            sb.append("(").append(getParameterSignature(mType)).append(")");
            sb.append(getReturnSignature(mType));
            return sb;
        }

        /*
         * Returns jvm internal signature.
         */
        static class JvmTypeVisitor extends JNIWriter.SimpleTypeVisitor<Type, StringBuilder> {

            @Override
            public Type visitClassType(Type.ClassType t, StringBuilder s) {
                setDeclaredType(t, s);
                return null;
            }

            @Override
            public Type visitArrayType(Type.ArrayType t, StringBuilder s) {
                s.append("[");
                return t.getComponentType().accept(this, s);
            }

            @Override
            public Type visitType(Type t, StringBuilder s) {
                if (t.isPrimitiveOrVoid()) {
                    s.append(getJvmPrimitiveSignature(t));
                    return null;
                }
                return t.accept(this, s);
            }
            private void setDeclaredType(Type t, StringBuilder s) {
                    String classname = t.tsym.getQualifiedName().toString();
                    classname = classname.replace('.', '/');
                    s.append("L").append(classname).append(";");
            }
            private String getJvmPrimitiveSignature(Type t) {
                switch (t.getKind()) {
                    case VOID:      return SIG_VOID;
                    case BOOLEAN:   return SIG_BOOLEAN;
                    case BYTE:      return SIG_BYTE;
                    case CHAR:      return SIG_CHAR;
                    case SHORT:     return SIG_SHORT;
                    case INT:       return SIG_INT;
                    case LONG:      return SIG_LONG;
                    case FLOAT:     return SIG_FLOAT;
                    case DOUBLE:    return SIG_DOUBLE;
                    default:
                        Assert.error("unknown type: should not happen");
                }
                return null;
            }
        }

        StringBuilder getJvmSignature(Type type) {
            Type t = types.erasure(type);
            StringBuilder sig = new StringBuilder();
            JvmTypeVisitor jv = new JvmTypeVisitor();
            jv.visitType(t, sig);
            return sig;
        }
    }

    static class SimpleTypeVisitor<R, P> implements Type.Visitor<R, P> {

        protected final R DEFAULT_VALUE;

        protected SimpleTypeVisitor() {
            DEFAULT_VALUE = null;
        }

        protected SimpleTypeVisitor(R defaultValue) {
            DEFAULT_VALUE = defaultValue;
        }

        protected R defaultAction(Type t, P p) {
            return DEFAULT_VALUE;
        }

        @Override
        public R visitClassType(Type.ClassType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitWildcardType(Type.WildcardType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitArrayType(Type.ArrayType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitMethodType(Type.MethodType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitPackageType(Type.PackageType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitTypeVar(Type.TypeVar t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitCapturedType(Type.CapturedType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitForAll(Type.ForAll t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitUndetVar(Type.UndetVar t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitErrorType(Type.ErrorType t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitType(Type t, P p) {
            return defaultAction(t, p);
        }

        @Override
        public R visitModuleType(Type.ModuleType t, P p) {
            return defaultAction(t, p);
        }
    }
}