/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program 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 for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.vm4brwsr;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.HashMap;

 import java.util.Map;

 import org.apidesign.bck2brwsr.core.ExtraJavaScript;

 import org.apidesign.vm4brwsr.ByteCodeParser.AnnotationParser;

 import org.apidesign.vm4brwsr.ByteCodeParser.ClassData;

 import org.apidesign.vm4brwsr.ByteCodeParser.FieldData;

 import org.apidesign.vm4brwsr.ByteCodeParser.MethodData;

 @ExtraJavaScript(processByteCode = false, resource="")

 final class ExportedSymbols {

     private final Bck2Brwsr.Resources resources;

     private final StringArray exported;

     private final Map<Object, Boolean> isMarkedAsExportedCache;

     ExportedSymbols(final Bck2Brwsr.Resources resources, StringArray explicitlyExported) {

         this.resources = resources;

         this.exported = explicitlyExported;

         isMarkedAsExportedCache = new HashMap<Object, Boolean>();

     }

     boolean isExported(ClassData classData) throws IOException {

         if (exported.contains(classData.getClassName())) {

             return true;

         }

         return classData.isPublic() && isMarkedAsExportedPackage(

                                            classData.getPkgName())

                    || isMarkedAsExported(classData);

     }

     boolean isExported(MethodData methodData) throws IOException {

         return isAccessible(methodData.access) && isExported(methodData.cls)

                    || isMarkedAsExported(methodData);

     }

     boolean isExported(FieldData fieldData) throws IOException {

         if (

             isAccessible(fieldData.access) && 

             isExported(fieldData.cls) || isMarkedAsExported(fieldData)

         ) {

             return true;

         }

         if (

             fieldData.isStatic() && fieldData.getName().equals("$VALUES") &&

             "java/lang/Enum".equals(fieldData.cls.getSuperClassName())

         ) {

             // enum values need to be exported

             return true;

         }

         return false;

     }

     private boolean isMarkedAsExportedPackage(String pkgName) {

         if (pkgName == null) {

             return false;

         }

         final Boolean cachedValue = isMarkedAsExportedCache.get(pkgName);

         if (cachedValue != null) {

             return cachedValue;

         }

         final boolean newValue = resolveIsMarkedAsExportedPackage(pkgName);

         isMarkedAsExportedCache.put(pkgName, newValue);

         return newValue;

     }

     private boolean isMarkedAsExported(ClassData classData)

             throws IOException {

         final Boolean cachedValue = isMarkedAsExportedCache.get(classData);

         if (cachedValue != null) {

             return cachedValue;

         }

         final boolean newValue =

                 isMarkedAsExported(classData.findAnnotationData(true),

                                    classData);

         isMarkedAsExportedCache.put(classData, newValue);

         return newValue;

     }

     private boolean isMarkedAsExported(MethodData methodData)

             throws IOException {

         return isMarkedAsExported(methodData.findAnnotationData(true),

                                   methodData.cls);

     }

     private boolean isMarkedAsExported(FieldData fieldData)

             throws IOException {

         return isMarkedAsExported(fieldData.findAnnotationData(true),

                                   fieldData.cls);

     }

     private boolean resolveIsMarkedAsExportedPackage(String pkgName) {

         try {

             final InputStream is =

                     resources.get(pkgName + "/package-info.class");

             if (is == null) {

                 return false;

             }

             try {

                 final ClassData pkgInfoClass = new ClassData(is);

                 return isMarkedAsExported(

                                pkgInfoClass.findAnnotationData(true),

                                pkgInfoClass);

             } finally {

                 is.close();

             }

         } catch (final IOException e) {

             return false;

         }

     }

     private boolean isMarkedAsExported(byte[] arrData, ClassData cd)

             throws IOException {

         if (arrData == null) {

             return false;

         }

         final boolean[] found = { false };

         final AnnotationParser annotationParser =

                 new AnnotationParser(false, false) {

                     @Override

                     protected void visitAnnotationStart(

                             String type,

                             boolean top) {

                         if (top && type.equals("Lorg/apidesign/bck2brwsr"

                                                    + "/core/Exported;")) {

                             found[0] = true;

                         }

                     }

                 };

         annotationParser.parse(arrData, cd);

         return found[0];

     }

     private static boolean isAccessible(int access) {

         return (access & (ByteCodeParser.ACC_PUBLIC

                               | ByteCodeParser.ACC_PROTECTED)) != 0;

     }

 }