/*

 * Copyright (c) 1999, 2012, 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.Writer;

import java.util.ArrayList;

import java.util.List;

import java.util.Stack;

import java.util.StringTokenizer;

import javax.lang.model.element.Element;

import javax.lang.model.element.ExecutableElement;

import javax.lang.model.element.Modifier;

import javax.lang.model.element.Name;

import javax.lang.model.element.TypeElement;

import javax.lang.model.element.VariableElement;

import javax.lang.model.type.ArrayType;

import javax.lang.model.type.DeclaredType;

import javax.lang.model.type.NoType;

import javax.lang.model.type.PrimitiveType;

import javax.lang.model.type.TypeKind;

import javax.lang.model.type.TypeMirror;

import javax.lang.model.type.TypeVariable;

import javax.lang.model.type.TypeVisitor;

import javax.lang.model.util.ElementFilter;

import javax.lang.model.util.Elements;

import javax.lang.model.util.SimpleTypeVisitor8;

import javax.lang.model.util.Types;

import javax.tools.FileObject;

import javax.tools.JavaFileManager;

import javax.tools.StandardLocation;

import com.sun.tools.javac.code.Attribute;

import com.sun.tools.javac.code.Flags;

import com.sun.tools.javac.code.Kinds;

import com.sun.tools.javac.code.Scope;

import com.sun.tools.javac.code.Symbol.ClassSymbol;

import com.sun.tools.javac.code.Symtab;

import com.sun.tools.javac.model.JavacElements;

import com.sun.tools.javac.model.JavacTypes;

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 static com.sun.tools.javac.main.Option.*;

/** 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<JNIWriter>();

    /** Access to files. */

    private final JavaFileManager fileManager;

    JavacElements elements;

    JavacTypes types;

    /** The log to use for verbose output.

     */

    private final Log log;

    /** Switch: verbose output.

     */

    private boolean verbose;

    /** Switch: check all nested classes of top level class

     */

    private boolean checkAll;

    private Mangle mangler;

    private Context context;

    private Symtab syms;

    private String lineSep;

    private final boolean isWindows =

        System.getProperty("os.name").startsWith("Windows");

    /** 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.

     */

    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()

        syms = Symtab.instance(context);

        lineSep = System.getProperty("line.separator");

    }

    private void lazyInit() {

        if (mangler == null) {

            elements = JavacElements.instance(context);

            types = JavacTypes.instance(context);

            mangler = new Mangle(elements, types);

        }

    }

    public boolean needsHeader(ClassSymbol c) {

        if (c.isLocal() || (c.flags() & Flags.SYNTHETIC) != 0)

            return false;

        if (checkAll)

            return needsHeader(c.outermostClass(), true);

        else

            return needsHeader(c, false);

    }

    private boolean needsHeader(ClassSymbol c, boolean checkNestedClasses) {

        if (c.isLocal() || (c.flags() & Flags.SYNTHETIC) != 0)

            return false;

        /* temporary code for backwards compatibility */

        for (Attribute.Compound a: c.annotations.getAttributes()) {

            if (a.type.tsym == syms.nativeHeaderType_old.tsym)

                return true;

        }

        /* end of temporary code for backwards compatibility */

        for (Scope.Entry i = c.members_field.elems; i != null; i = i.sibling) {

            if (i.sym.kind == Kinds.MTH && (i.sym.flags() & Flags.NATIVE) != 0)

                return true;

            for (Attribute.Compound a: i.sym.annotations.getAttributes()) {

                if (a.type.tsym == syms.nativeHeaderType.tsym)

                    return true;

            }

        }

        if (checkNestedClasses) {

            for (Scope.Entry i = c.members_field.elems; i != null; i = i.sibling) {

                if ((i.sym.kind == Kinds.TYP) && needsHeader(((ClassSymbol) i.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.

     */

    public FileObject write(ClassSymbol c)

        throws IOException

    {

        String className = c.flatName().toString();

        FileObject outFile

            = fileManager.getFileForOutput(StandardLocation.NATIVE_HEADER_OUTPUT,

                "", className.replaceAll("[.$]", "_") + ".h", null);

        Writer out = outFile.openWriter();

        try {

            write(out, c);

            if (verbose)

                log.printVerbose("wrote.file", outFile);

            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(Writer out, ClassSymbol sym)

            throws IOException {

        lazyInit();

        try {

            String cname = mangler.mangle(sym.fullname, Mangle.Type.CLASS);

            println(out, fileTop());

            println(out, includes());

            println(out, guardBegin(cname));

            println(out, cppGuardBegin());

            writeStatics(out, sym);

            writeMethods(out, sym, cname);

            println(out, cppGuardEnd());

            println(out, guardEnd(cname));

        } catch (TypeSignature.SignatureException e) {

            throw new IOException(e);

        }

    }

    protected void writeStatics(Writer out, ClassSymbol sym) throws IOException {

        List<VariableElement> classfields = getAllFields(sym);

        for (VariableElement v: classfields) {

            if (!v.getModifiers().contains(Modifier.STATIC))

                continue;

            String s = null;

            s = defineForStatic(sym, v);

            if (s != null) {

                println(out, s);

            }

        }

    }

    /**

     * Including super class fields.

     */

    List<VariableElement> getAllFields(TypeElement subclazz) {

        List<VariableElement> fields = new ArrayList<VariableElement>();

        TypeElement cd = null;

        Stack<TypeElement> s = new Stack<TypeElement>();

        cd = subclazz;

        while (true) {

            s.push(cd);

            TypeElement c = (TypeElement) (types.asElement(cd.getSuperclass()));

            if (c == null)

                break;

            cd = c;

        }

        while (!s.empty()) {

            cd = s.pop();

            fields.addAll(ElementFilter.fieldsIn(cd.getEnclosedElements()));

        }

        return fields;

    }

    protected String defineForStatic(TypeElement c, VariableElement f) {

        CharSequence cnamedoc = c.getQualifiedName();

        CharSequence fnamedoc = f.getSimpleName();

        String cname = mangler.mangle(cnamedoc, Mangle.Type.CLASS);

        String fname = mangler.mangle(fnamedoc, Mangle.Type.FIELDSTUB);

        Assert.check(f.getModifiers().contains(Modifier.STATIC));

        if (f.getModifiers().contains(Modifier.FINAL)) {

            Object value = null;

            value = f.getConstantValue();

            if (value != null) { /* so it is a ConstantExpression */

                String constString = null;

                if ((value instanceof Integer)

                    || (value instanceof Byte)

                    || (value instanceof Short)) {

                    /* covers byte, short, int */

                    constString = value.toString() + "L";

                } else if (value instanceof Boolean) {

                    constString = ((Boolean) value) ? "1L" : "0L";

                } else if (value instanceof Character) {

                    Character ch = (Character) value;

                    constString = String.valueOf(((int) ch) & 0xffff) + "L";

                } else if (value instanceof Long) {

                    // Visual C++ supports the i64 suffix, not LL.

                    if (isWindows)

                        constString = value.toString() + "i64";

                    else

                        constString = value.toString() + "LL";

                } else if (value instanceof Float) {

                    /* bug for bug */

                    float fv = ((Float)value).floatValue();

                    if (Float.isInfinite(fv))

                        constString = ((fv < 0) ? "-" : "") + "Inff";

                    else

                        constString = value.toString() + "f";

                } else if (value instanceof Double) {

                    /* bug for bug */

                    double d = ((Double)value).doubleValue();

                    if (Double.isInfinite(d))

                        constString = ((d < 0) ? "-" : "") + "InfD";

                    else

                        constString = value.toString();

                }

                if (constString != null) {

                    StringBuilder s = new StringBuilder("#undef ");

                    s.append(cname); s.append("_"); s.append(fname); s.append(lineSep);

                    s.append("#define "); s.append(cname); s.append("_");

                    s.append(fname); s.append(" "); s.append(constString);

                    return s.toString();

                }

            }

        }

        return null;

    }

    protected void writeMethods(Writer out, ClassSymbol sym, String cname)

            throws IOException, TypeSignature.SignatureException {

        List<ExecutableElement> classmethods = ElementFilter.methodsIn(sym.getEnclosedElements());

        for (ExecutableElement md: classmethods) {

            if(md.getModifiers().contains(Modifier.NATIVE)){

                TypeMirror mtr = types.erasure(md.getReturnType());

                String sig = signature(md);

                TypeSignature newtypesig = new TypeSignature(elements);

                CharSequence methodName = md.getSimpleName();

                boolean longName = false;

                for (ExecutableElement md2: classmethods) {

                    if ((md2 != md)

                        && (methodName.equals(md2.getSimpleName()))

                        && (md2.getModifiers().contains(Modifier.NATIVE)))

                        longName = true;

                }

                println(out, "/*");

                println(out, " * Class:     " + cname);

                println(out, " * Method:    " +

                           mangler.mangle(methodName, Mangle.Type.FIELDSTUB));

                println(out, " * Signature: " + newtypesig.getTypeSignature(sig, mtr));

                println(out, " */");

                println(out, "JNIEXPORT " + jniType(mtr) +

                           " JNICALL " +

                           mangler.mangleMethod(md, sym,

                                               (longName) ?

                                               Mangle.Type.METHOD_JNI_LONG :

                                               Mangle.Type.METHOD_JNI_SHORT));

                print(out, "  (JNIEnv *, ");

                List<? extends VariableElement> paramargs = md.getParameters();

                List<TypeMirror> args = new ArrayList<TypeMirror>();

                for (VariableElement p: paramargs) {

                    args.add(types.erasure(p.asType()));

                }

                if (md.getModifiers().contains(Modifier.STATIC))

                    print(out, "jclass");

                else

                    print(out, "jobject");

                for (TypeMirror arg: args) {

                    print(out, ", ");

                    print(out, jniType(arg));

                }

                println(out, ");"

                        + lineSep);

            }

        }

    }

    // c.f. MethodDoc.signature

    String signature(ExecutableElement e) {

        StringBuilder sb = new StringBuilder("(");

        String sep = "";

        for (VariableElement p: e.getParameters()) {

            sb.append(sep);

            sb.append(types.erasure(p.asType()).toString());

            sep = ",";

        }

        sb.append(")");

        return sb.toString();

    }

    protected final String jniType(TypeMirror t) {

        TypeElement throwable = elements.getTypeElement("java.lang.Throwable");

        TypeElement jClass = elements.getTypeElement("java.lang.Class");

        TypeElement jString = elements.getTypeElement("java.lang.String");

        Element tclassDoc = types.asElement(t);

        switch (t.getKind()) {

            case ARRAY: {

                TypeMirror ct = ((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 (tclassDoc.equals(jString))

                    return "jstring";

                else if (types.isAssignable(t, throwable.asType()))

                    return "jthrowable";

                else if (types.isAssignable(t, jClass.asType()))

                    return "jclass";

                else

                    return "jobject";

            }

        }

        Assert.check(false, "jni unknown type");

        return null; /* dead code. */

    }

    protected String fileTop() {

        return "/* DO NOT EDIT THIS FILE - it is machine generated */";

    }

    protected String includes() {

        return "#include <jni.h>";

    }

    /*

     * Deal with the C pre-processor.

     */

    protected String cppGuardBegin() {

        return "#ifdef __cplusplus" + lineSep

                + "extern \"C\" {" + lineSep

                + "#endif";

    }

    protected String cppGuardEnd() {

        return "#ifdef __cplusplus" + lineSep

                + "}" + lineSep

                + "#endif";

    }

    protected String guardBegin(String cname) {

        return "/* Header for class " + cname + " */" + lineSep

                + lineSep

                + "#ifndef _Included_" + cname + lineSep

                + "#define _Included_" + cname;

    }

    protected String guardEnd(String cname) {

        return "#endif";

    }

    protected void print(Writer out, String text) throws IOException {

        out.write(text);

    }

    protected void println(Writer out, String text) throws IOException {

        out.write(text);

        out.write(lineSep);

    }

    private static class Mangle {

        public static class Type {

            public static final int CLASS            = 1;

            public static final int FIELDSTUB        = 2;

            public static final int FIELD            = 3;

            public static final int JNI              = 4;

            public static final int SIGNATURE        = 5;

            public static final int METHOD_JDK_1     = 6;

            public static final int METHOD_JNI_SHORT = 7;

            public static final int METHOD_JNI_LONG  = 8;

        };

        private Elements elems;

        private Types types;

        Mangle(Elements elems, Types types) {

            this.elems = elems;

            this.types = types;

        }

        public final String mangle(CharSequence name, int 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);

                } else if ((ch == '.') &&

                           mtype == Mangle.Type.CLASS) {

                    result.append('_');

                } else if (( ch == '$') &&

                           mtype == Mangle.Type.CLASS) {

                    result.append('_');

                    result.append('_');