/*

 * Copyright (c) 2011, 2014, 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.api;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.Reader;

import java.io.Writer;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import java.net.URI;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Locale;

import java.util.Map;

import java.util.Objects;

import java.util.Set;

import javax.lang.model.element.Modifier;

import javax.lang.model.element.NestingKind;

import javax.tools.Diagnostic;

import javax.tools.DiagnosticListener;

import javax.tools.FileObject;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileManager.Location;

import javax.tools.JavaFileObject;

import javax.tools.JavaFileObject.Kind;

import javax.tools.StandardJavaFileManager;

import com.sun.source.util.TaskEvent;

import com.sun.source.util.TaskListener;

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

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

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

import com.sun.tools.javac.util.DefinedBy.Api;

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

/**

 *  Wrap objects to enable unchecked exceptions to be caught and handled.

 *

 *  For each method, exceptions are handled as follows:

 *  <ul>

 *  <li>Checked exceptions are left alone and propogate upwards in the

 *      obvious way, since they are an expected aspect of the method's

 *      specification.

 *  <li>Unchecked exceptions which have already been caught and wrapped in

 *      ClientCodeException are left alone to continue propogating upwards.

 *  <li>All other unchecked exceptions (i.e. subtypes of RuntimeException

 *      and Error) and caught, and rethrown as a ClientCodeException with

 *      its cause set to the original exception.

 *  </ul>

 *

 *  The intent is that ClientCodeException can be caught at an appropriate point

 *  in the program and can be distinguished from any unanticipated unchecked

 *  exceptions arising in the main body of the code (i.e. bugs.) When the

 *  ClientCodeException has been caught, either a suitable message can be

 *  generated, or if appropriate, the original cause can be rethrown.

 *

 *  <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 ClientCodeWrapper {

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.TYPE)

    public @interface Trusted { }

    public static ClientCodeWrapper instance(Context context) {

        ClientCodeWrapper instance = context.get(ClientCodeWrapper.class);

        if (instance == null)

            instance = new ClientCodeWrapper(context);

        return instance;

    }

    /**

     * A map to cache the results of whether or not a specific classes can

     * be "trusted", and thus does not need to be wrapped.

     */

    Map<Class<?>, Boolean> trustedClasses;

    protected ClientCodeWrapper(Context context) {

        trustedClasses = new HashMap<>();

    }

    public JavaFileManager wrap(JavaFileManager fm) {

        if (isTrusted(fm))

            return fm;

        if (fm instanceof StandardJavaFileManager)

            return new WrappedStandardJavaFileManager((StandardJavaFileManager) fm);

        return new WrappedJavaFileManager(fm);

    }

    public FileObject wrap(FileObject fo) {

        if (fo == null || isTrusted(fo))

            return fo;

        return new WrappedFileObject(fo);

    }

    FileObject unwrap(FileObject fo) {

        if (fo instanceof WrappedFileObject)

            return ((WrappedFileObject) fo).clientFileObject;

        else

            return fo;

    }

    public JavaFileObject wrap(JavaFileObject fo) {

        if (fo == null || isTrusted(fo))

            return fo;

        return new WrappedJavaFileObject(fo);

    }

    public Iterable<JavaFileObject> wrapJavaFileObjects(Iterable<? extends JavaFileObject> list) {

        List<JavaFileObject> wrapped = new ArrayList<>();

        for (JavaFileObject fo : list)

            wrapped.add(wrap(fo));

        return Collections.unmodifiableList(wrapped);

    }

    JavaFileObject unwrap(JavaFileObject fo) {

        if (fo instanceof WrappedJavaFileObject)

            return ((JavaFileObject) ((WrappedJavaFileObject) fo).clientFileObject);

        else

            return fo;

    }

    public <T /*super JavaFileOject*/> DiagnosticListener<T> wrap(DiagnosticListener<T> dl) {

        if (isTrusted(dl))

            return dl;

        return new WrappedDiagnosticListener<>(dl);

    }

    TaskListener wrap(TaskListener tl) {

        if (isTrusted(tl))

            return tl;

        return new WrappedTaskListener(tl);

    }

    TaskListener unwrap(TaskListener l) {

        if (l instanceof WrappedTaskListener)

            return ((WrappedTaskListener) l).clientTaskListener;

        else

            return l;

    }

    Collection<TaskListener> unwrap(Collection<? extends TaskListener> listeners) {

        Collection<TaskListener> c = new ArrayList<>(listeners.size());

        for (TaskListener l: listeners)

            c.add(unwrap(l));

        return c;

    }

    @SuppressWarnings("unchecked")

    private <T> Diagnostic<T> unwrap(final Diagnostic<T> diagnostic) {

        if (diagnostic instanceof JCDiagnostic) {

            JCDiagnostic d = (JCDiagnostic) diagnostic;

            return (Diagnostic<T>) new DiagnosticSourceUnwrapper(d);

        } else {

            return diagnostic;

        }

    }

    protected boolean isTrusted(Object o) {

        Class<?> c = o.getClass();

        Boolean trusted = trustedClasses.get(c);

        if (trusted == null) {

            trusted = c.getName().startsWith("com.sun.tools.javac.")

                    || c.isAnnotationPresent(Trusted.class);

            trustedClasses.put(c, trusted);

        }

        return trusted;

    }

    private String wrappedToString(Class<?> wrapperClass, Object wrapped) {

        return wrapperClass.getSimpleName() + "[" + wrapped + "]";

    }

    // <editor-fold defaultstate="collapsed" desc="Wrapper classes">

    protected class WrappedJavaFileManager implements JavaFileManager {

        protected JavaFileManager clientJavaFileManager;

        WrappedJavaFileManager(JavaFileManager clientJavaFileManager) {

            this.clientJavaFileManager = Objects.requireNonNull(clientJavaFileManager);

        }

        @Override @DefinedBy(Api.COMPILER)

        public ClassLoader getClassLoader(Location location) {

            try {

                return clientJavaFileManager.getClassLoader(location);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public Iterable<JavaFileObject> list(Location location, String packageName, Set<Kind> kinds, boolean recurse) throws IOException {

            try {

                return wrapJavaFileObjects(clientJavaFileManager.list(location, packageName, kinds, recurse));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public String inferBinaryName(Location location, JavaFileObject file) {

            try {

                return clientJavaFileManager.inferBinaryName(location, unwrap(file));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public boolean isSameFile(FileObject a, FileObject b) {

            try {

                return clientJavaFileManager.isSameFile(unwrap(a), unwrap(b));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public boolean handleOption(String current, Iterator<String> remaining) {

            try {

                return clientJavaFileManager.handleOption(current, remaining);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public boolean hasLocation(Location location) {

            try {

                return clientJavaFileManager.hasLocation(location);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public JavaFileObject getJavaFileForInput(Location location, String className, Kind kind) throws IOException {

            try {

                return wrap(clientJavaFileManager.getJavaFileForInput(location, className, kind));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind, FileObject sibling) throws IOException {

            try {

                return wrap(clientJavaFileManager.getJavaFileForOutput(location, className, kind, unwrap(sibling)));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public FileObject getFileForInput(Location location, String packageName, String relativeName) throws IOException {

            try {

                return wrap(clientJavaFileManager.getFileForInput(location, packageName, relativeName));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public FileObject getFileForOutput(Location location, String packageName, String relativeName, FileObject sibling) throws IOException {

            try {

                return wrap(clientJavaFileManager.getFileForOutput(location, packageName, relativeName, unwrap(sibling)));

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public void flush() throws IOException {

            try {

                clientJavaFileManager.flush();

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public void close() throws IOException {

            try {

                clientJavaFileManager.close();

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public int isSupportedOption(String option) {

            try {

                return clientJavaFileManager.isSupportedOption(option);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override

        public String toString() {

            return wrappedToString(getClass(), clientJavaFileManager);

        }

    }

    protected class WrappedStandardJavaFileManager extends WrappedJavaFileManager

            implements StandardJavaFileManager {

        WrappedStandardJavaFileManager(StandardJavaFileManager clientJavaFileManager) {

            super(clientJavaFileManager);

        }

        @Override @DefinedBy(Api.COMPILER)

        public Iterable<? extends JavaFileObject> getJavaFileObjectsFromFiles(Iterable<? extends File> files) {

            try {

                return ((StandardJavaFileManager)clientJavaFileManager).getJavaFileObjectsFromFiles(files);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public Iterable<? extends JavaFileObject> getJavaFileObjects(File... files) {

            try {

                return ((StandardJavaFileManager)clientJavaFileManager).getJavaFileObjects(files);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public Iterable<? extends JavaFileObject> getJavaFileObjectsFromStrings(Iterable<String> names) {

            try {

                return ((StandardJavaFileManager)clientJavaFileManager).getJavaFileObjectsFromStrings(names);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public Iterable<? extends JavaFileObject> getJavaFileObjects(String... names) {

            try {

                return ((StandardJavaFileManager)clientJavaFileManager).getJavaFileObjects(names);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public void setLocation(Location location, Iterable<? extends File> path) throws IOException {

            try {

                ((StandardJavaFileManager)clientJavaFileManager).setLocation(location, path);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public Iterable<? extends File> getLocation(Location location) {

            try {

                return ((StandardJavaFileManager)clientJavaFileManager).getLocation(location);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

    }

    protected class WrappedFileObject implements FileObject {

        protected FileObject clientFileObject;

        WrappedFileObject(FileObject clientFileObject) {

            this.clientFileObject = Objects.requireNonNull(clientFileObject);

        }

        @Override @DefinedBy(Api.COMPILER)

        public URI toUri() {

            try {

                return clientFileObject.toUri();

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public String getName() {

            try {

                return clientFileObject.getName();

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public InputStream openInputStream() throws IOException {

            try {

                return clientFileObject.openInputStream();

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public OutputStream openOutputStream() throws IOException {

            try {

                return clientFileObject.openOutputStream();

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public Reader openReader(boolean ignoreEncodingErrors) throws IOException {

            try {

                return clientFileObject.openReader(ignoreEncodingErrors);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }

        @Override @DefinedBy(Api.COMPILER)

        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

            try {

                return clientFileObject.getCharContent(ignoreEncodingErrors);

            } catch (ClientCodeException e) {

                throw e;

            } catch (RuntimeException | Error e) {

                throw new ClientCodeException(e);

            }

        }