BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
License Version 2.0 (the "License"); you may not use this file
except in compliance with the License. You may obtain a copy of
the License at http://www.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2002 Anders Bengtsson 
Copyright (C) 2002-2004 Jan Arne Petersen 
Copyright (C) 2004 Thomas E Enebo 
Copyright (C) 2004 Stefan Matthias Aust 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
END LICENSE BLOCK /***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2002 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2002-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
 * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/

package org.jruby;

import java.lang.management.GarbageCollectorMXBean;
import java.lang.management.ManagementFactory;
import org.jruby.anno.JRubyMethod;
import org.jruby.anno.JRubyModule;
import org.jruby.common.IRubyWarnings.ID;
import org.jruby.runtime.ThreadContext;
import static org.jruby.runtime.Visibility.*;
import org.jruby.runtime.builtin.IRubyObject;

GC (Garbage Collection) Module
Note: Since we rely on Java's memory model we can't provide the
kind of control over garbage collection that MRI provides.  Also note
that since all Ruby libraries make GC assumptions based on MRI's GC
that we decided to no-op explicit collection through these APIs.
You can use Java Integration in your libraries to force a Java
GC (assuming you really want to).
/**
 * GC (Garbage Collection) Module
 *
 * Note: Since we rely on Java's memory model we can't provide the
 * kind of control over garbage collection that MRI provides.  Also note
 * that since all Ruby libraries make GC assumptions based on MRI's GC
 * that we decided to no-op explicit collection through these APIs.
 * You can use Java Integration in your libraries to force a Java
 * GC (assuming you really want to).
 *
 */
@JRubyModule(name="GC")
public class RubyGC {
    private static volatile boolean gcDisabled = false;
    private static volatile boolean stress = false;

    public static RubyModule createGCModule(Ruby runtime) {
        RubyModule result = runtime.defineModule("GC");
        runtime.setGC(result);
        
        result.defineAnnotatedMethods(RubyGC.class);
        
        return result;        
    }

    @JRubyMethod(module = true, visibility = PRIVATE)
    public static IRubyObject start(ThreadContext context, IRubyObject recv) {
        return context.nil;
    }

    @JRubyMethod
    public static IRubyObject garbage_collect(ThreadContext context, IRubyObject recv) {
        return context.nil;
    }

    @JRubyMethod(module = true, visibility = PRIVATE)
    public static IRubyObject enable(ThreadContext context, IRubyObject recv) {
        Ruby runtime = context.runtime;
        emptyImplementationWarning(runtime, ID.GC_ENABLE_UNIMPLEMENTED, "GC.enable");
        boolean old = gcDisabled;
        gcDisabled = false;
        return runtime.newBoolean(old);
    }

    @JRubyMethod(module = true, visibility = PRIVATE)
    public static IRubyObject disable(ThreadContext context, IRubyObject recv) {
        Ruby runtime = context.runtime;
        emptyImplementationWarning(runtime, ID.GC_DISABLE_UNIMPLEMENTED, "GC.disable");
        boolean old = gcDisabled;
        gcDisabled = true;
        return runtime.newBoolean(old);
    }

    @JRubyMethod(module = true, visibility = PRIVATE)
    public static IRubyObject stress(ThreadContext context, IRubyObject recv) {
        return context.runtime.newBoolean(stress);
    }

    @JRubyMethod(name = "stress=", module = true, visibility = PRIVATE)
    public static IRubyObject stress_set(ThreadContext context, IRubyObject recv, IRubyObject arg) {
        Ruby runtime = context.runtime;
        emptyImplementationWarning(runtime, ID.GC_STRESS_UNIMPLEMENTED, "GC.stress=");
        stress = arg.isTrue();
        return runtime.newBoolean(stress);
    }
    
    @JRubyMethod(module = true, visibility = PRIVATE)
    public static IRubyObject count(ThreadContext context, IRubyObject recv) {
        try {
            int count = getCollectionCount();
            return context.runtime.newFixnum(count);
        } catch (Throwable t) {
            return RubyFixnum.minus_one(context.runtime);
        }
    }

    private static void emptyImplementationWarning(Ruby runtime, ID id, String name) {
        runtime.getWarnings().warnOnce(id, name + " does nothing on JRuby");
    }

    public static int getCollectionCount() {
        int count = 0;
        for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
            count += bean.getCollectionCount();
        }
        return count;
    }

    public static long getCollectionTime() {
        long time = 0;
        for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
            time += bean.getCollectionTime();
        }
        return time;
    }

}