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) 2001 Alan Moore 
Copyright (C) 2001-2004 Jan Arne Petersen 
Copyright (C) 2002-2004 Anders Bengtsson 
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) 2001 Alan Moore <alan_moore@gmx.net>
 * Copyright (C) 2001-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * 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.util.ArrayList;
import static org.jruby.RubyEnumerator.enumeratorize;

import java.util.Iterator;

import org.jruby.anno.JRubyMethod;
import org.jruby.anno.JRubyModule;
import org.jruby.runtime.Block;
import org.jruby.runtime.ObjectAllocator;
import org.jruby.runtime.ThreadContext;
import static org.jruby.runtime.Visibility.*;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.util.collections.WeakValuedIdentityMap;

@JRubyModule(name="ObjectSpace")
public class RubyObjectSpace {

    
Create the ObjectSpace module and add it to the Ruby runtime.
/** Create the ObjectSpace module and add it to the Ruby runtime.
     *
     */
    public static RubyModule createObjectSpaceModule(Ruby runtime) {
        RubyModule objectSpaceModule = runtime.defineModule("ObjectSpace");
        runtime.setObjectSpaceModule(objectSpaceModule);

        objectSpaceModule.defineAnnotatedMethods(RubyObjectSpace.class);

        WeakMap.createWeakMap(runtime);

        return objectSpaceModule;
    }

    @JRubyMethod(required = 1, optional = 1, module = true, visibility = PRIVATE)
    public static IRubyObject define_finalizer(IRubyObject recv, IRubyObject[] args, Block block) {
        Ruby runtime = recv.getRuntime();
        IRubyObject finalizer;
        if (args.length == 2) {
            finalizer = args[1];
            if (!finalizer.respondsTo("call")) {
                throw runtime.newArgumentError("wrong type argument " + finalizer.getType() + " (should be callable)");
            }
        } else {
            finalizer = runtime.newProc(Block.Type.PROC, block);
        }
        IRubyObject obj = args[0];
        runtime.getObjectSpace().addFinalizer(obj, finalizer);
        return runtime.newArray(RubyFixnum.zero(runtime), finalizer);
    }

    @JRubyMethod(required = 1, module = true, visibility = PRIVATE)
    public static IRubyObject undefine_finalizer(IRubyObject recv, IRubyObject obj, Block block) {
        recv.getRuntime().getObjectSpace().removeFinalizers(RubyNumeric.fix2long(obj.id()));
        return recv;
    }

    @JRubyMethod(name = "_id2ref", required = 1, module = true, visibility = PRIVATE)
    public static IRubyObject id2ref(IRubyObject recv, IRubyObject id) {
        final Ruby runtime = id.getRuntime();
        if (!(id instanceof RubyFixnum)) {
            throw runtime.newTypeError(id, runtime.getFixnum());
        }
        long longId = ((RubyFixnum) id).getLongValue();
        if (longId == 0) {
            return runtime.getFalse();
        } else if (longId == 20) {
            return runtime.getTrue();
        } else if (longId == 8) {
            return runtime.getNil();
        } else if (longId % 2 != 0) {
            // odd
            return runtime.newFixnum((longId - 1) / 2);
        } else {
            if (runtime.isObjectSpaceEnabled()) {
                IRubyObject object = runtime.getObjectSpace().id2ref(longId);
                if (object == null) {
                    return runtime.getNil();
                }
                return object;
            } else {
                runtime.getWarnings().warn("ObjectSpace is disabled; _id2ref only supports immediates, pass -X+O to enable");
                throw runtime.newRangeError(String.format("0x%016x is not id value", longId));
            }
        }
    }

    public static IRubyObject each_objectInternal(final ThreadContext context, IRubyObject recv, IRubyObject[] args, final Block block) {
        final Ruby runtime = context.runtime;
        final RubyModule rubyClass;
        if (args.length == 0) {
            rubyClass = runtime.getObject();
        } else {
            if (!(args[0] instanceof RubyModule)) throw runtime.newTypeError("class or module required");
            rubyClass = (RubyModule) args[0];
        }
        if (rubyClass == runtime.getClassClass() || rubyClass == runtime.getModule()) {

            final ArrayList<IRubyObject> modules = new ArrayList<>(96);
            runtime.eachModule((module) -> {
                    if (rubyClass.isInstance(module)) {
                        if (!(module instanceof IncludedModule)) {
                            // do nothing for included wrappers or singleton classes
                            modules.add(module); // store the module to avoid concurrent modification exceptions
                        }
                    }
            });

            final int count = modules.size();
            for (int i = 0; i<count; i++) {
                block.yield(context, modules.get(i));
            }
            return runtime.newFixnum(count);
        }
        if (rubyClass.getClass() == MetaClass.class) {
            // each_object(Cls.singleton_class) is basically a walk of Cls and all descendants of Cls.
            // In other words, this is walking all instances of Cls's singleton class and its subclasses.
            IRubyObject attached = ((MetaClass) args[0]).getAttached();
            block.yield(context, attached); int count = 1;
            if (attached instanceof RubyClass) {
                for (RubyClass child : ((RubyClass) attached).subclasses(true)) {
                    if (!(child instanceof IncludedModule)) {
                        // do nothing for included wrappers or singleton classes
                        count++; block.yield(context, child);
                    }
                }
            }
            return runtime.newFixnum(count);
        }
        if ( ! runtime.isObjectSpaceEnabled() ) {
            throw runtime.newRuntimeError("ObjectSpace is disabled; each_object will only work with Class, pass -X+O to enable");
        }
        final Iterator iter = runtime.getObjectSpace().iterator(rubyClass);
        IRubyObject obj; int count = 0;
        while ((obj = (IRubyObject) iter.next()) != null) {
            count++; block.yield(context, obj);
        }
        return runtime.newFixnum(count);
    }

    @JRubyMethod(name = "each_object", optional = 1, module = true, visibility = PRIVATE)
    public static IRubyObject each_object(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
        return block.isGiven() ? each_objectInternal(context, recv, args, block) : enumeratorize(context.runtime, recv, "each_object", args);
    }

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

    public static class WeakMap extends RubyObject {
        static void createWeakMap(Ruby runtime) {
            RubyClass weakMap = runtime.getObjectSpaceModule().defineClassUnder("WeakMap", runtime.getObject(), new ObjectAllocator() {
                public IRubyObject allocate(Ruby runtime, RubyClass klazz) {
                    return new WeakMap(runtime, klazz);
                }
            });

            weakMap.defineAnnotatedMethods(WeakMap.class);
        }

        public WeakMap(Ruby runtime, RubyClass cls) {
            super(runtime, cls);
        }

        @JRubyMethod(name = "[]")
        public IRubyObject op_aref(ThreadContext context, IRubyObject key) {
            IRubyObject value = map.get(key);
            if (value != null) return value;
            return context.nil;
        }

        @JRubyMethod(name = "[]=")
        public IRubyObject op_aref(ThreadContext context, IRubyObject key, IRubyObject value) {
            map.put(key, value);
            return context.runtime.newFixnum(System.identityHashCode(value));
        }

        @JRubyMethod(name = "key?")
        public IRubyObject key_p(ThreadContext context, IRubyObject key) {
            return context.runtime.newBoolean(map.get(key) != null);
        }

        private final WeakValuedIdentityMap<IRubyObject, IRubyObject> map = new WeakValuedIdentityMap<IRubyObject, IRubyObject>();
    }
}