/*
 * Copyright (c) 2001, 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.comp;

import java.util.AbstractQueue;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import javax.tools.JavaFileObject;

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

A queue of all as yet unattributed 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.
/** A queue of all as yet unattributed 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 Todo extends AbstractQueue<Env<AttrContext>> {
    
The context key for the todo list. /** The context key for the todo list. */
    protected static final Context.Key<Todo> todoKey = new Context.Key<>();

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

    
Create a new todo list. /** Create a new todo list. */
    protected Todo(Context context) {
        context.put(todoKey, this);
    }

    public void append(Env<AttrContext> env) {
        add(env);
    }

    @Override
    public Iterator<Env<AttrContext>> iterator() {
        return contents.iterator();
    }

    @Override
    public int size() {
        return contents.size();
    }

    public boolean offer(Env<AttrContext> e) {
        if (contents.add(e)) {
            if (contentsByFile != null)
                addByFile(e);
            return true;
        } else {
            return false;
        }
    }

    
Removes all unattributed classes except those belonging to the given
collection of files.
Params:
sourceFiles – The source files of the classes to keep./**
     * Removes all unattributed classes except those belonging to the given
     * collection of files.
     *
     * @param sourceFiles The source files of the classes to keep.
     */
    public void retainFiles(Collection<? extends JavaFileObject> sourceFiles) {
        for (Iterator<Env<AttrContext>> it = contents.iterator(); it.hasNext(); ) {
            Env<AttrContext> env = it.next();
            if (!sourceFiles.contains(env.toplevel.sourcefile)) {
                if (contentsByFile != null) removeByFile(env);
                it.remove();
            }
        }
    }

    public Env<AttrContext> poll() {
        if (size() == 0)
            return null;
        Env<AttrContext> env = contents.remove(0);
        if (contentsByFile != null)
            removeByFile(env);
        return env;
    }

    public Env<AttrContext> peek() {
        return (size() == 0 ? null : contents.get(0));
    }

    public Queue<Queue<Env<AttrContext>>> groupByFile() {
        if (contentsByFile == null) {
            contentsByFile = new LinkedList<>();
            for (Env<AttrContext> env: contents) {
                addByFile(env);
            }
        }
        return contentsByFile;
    }

    private void addByFile(Env<AttrContext> env) {
        JavaFileObject file = env.toplevel.sourcefile;
        if (fileMap == null)
            fileMap = new HashMap<>();
        FileQueue fq = fileMap.get(file);
        if (fq == null) {
            fq = new FileQueue();
            fileMap.put(file, fq);
            contentsByFile.add(fq);
        }
        fq.fileContents.add(env);
    }

    private void removeByFile(Env<AttrContext> env) {
        JavaFileObject file = env.toplevel.sourcefile;
        FileQueue fq = fileMap.get(file);
        if (fq == null)
            return;
        if (fq.fileContents.remove(env)) {
            if (fq.isEmpty()) {
                fileMap.remove(file);
                contentsByFile.remove(fq);
            }
        }
    }

    LinkedList<Env<AttrContext>> contents = new LinkedList<>();
    LinkedList<Queue<Env<AttrContext>>> contentsByFile;
    Map<JavaFileObject, FileQueue> fileMap;

    class FileQueue extends AbstractQueue<Env<AttrContext>> {
        @Override
        public Iterator<Env<AttrContext>> iterator() {
            return fileContents.iterator();
        }

        @Override
        public int size() {
            return fileContents.size();
        }

        public boolean offer(Env<AttrContext> e) {
            if (fileContents.offer(e)) {
                contents.add(e);
                return true;
            }
            return false;
        }

        public Env<AttrContext> poll() {
            if (fileContents.size() == 0)
                return null;
            Env<AttrContext> env = fileContents.remove(0);
            contents.remove(env);
            return env;
        }

        public Env<AttrContext> peek() {
            return (fileContents.size() == 0 ? null : fileContents.get(0));
        }

        LinkedList<Env<AttrContext>> fileContents = new LinkedList<>();
    }
}