1 /*
   2  * Copyright (c) 2010, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.nashorn.internal.runtime;
  27 
  28 import static jdk.nashorn.internal.codegen.CompilerConstants.virtualCallNoLookup;
  29 
  30 import java.util.concurrent.atomic.LongAdder;
  31 import jdk.nashorn.internal.codegen.CompilerConstants;
  32 
  33 /**
  34  * A {@link ScriptObject} subclass for objects that act as scope.
  35  */
  36 public class Scope extends ScriptObject {
  37 
  38     /* This is used to store return state of split functions. */
  39     private int splitState = -1;
  40 
  41     /** This is updated only in debug mode - counts number of {@code ScriptObject} instances created that are scope */
  42     private static final LongAdder count = Context.DEBUG ? new LongAdder() : null;
  43 
  44     /** Method handle that points to {@link Scope#getSplitState}. */
  45     public static final CompilerConstants.Call GET_SPLIT_STATE = virtualCallNoLookup(Scope.class, "getSplitState", int.class);
  46     /** Method handle that points to {@link Scope#setSplitState(int)}. */
  47     public static final CompilerConstants.Call SET_SPLIT_STATE = virtualCallNoLookup(Scope.class, "setSplitState", void.class, int.class);
  48 
  49     /**
  50      * Constructor
  51      *
  52      * @param map initial property map
  53      */
  54     public Scope(final PropertyMap map) {
  55         super(map);
  56         incrementCount();
  57     }
  58 
  59     /**
  60      * Constructor
  61      *
  62      * @param proto parent scope
  63      * @param map   initial property map
  64      */
  65     public Scope(final ScriptObject proto, final PropertyMap map) {
  66         super(proto, map);
  67         incrementCount();
  68     }
  69 
  70     /**
  71      * Constructor
  72      *
  73      * @param map            property map
  74      * @param primitiveSpill primitive spill array
  75      * @param objectSpill    reference spill array
  76      */
  77     public Scope(final PropertyMap map, final long[] primitiveSpill, final Object[] objectSpill) {
  78         super(map, primitiveSpill, objectSpill);
  79         incrementCount();
  80     }
  81 
  82     @Override
  83     public boolean isScope() {
  84         return true;
  85     }
  86 
  87     @Override
  88     boolean hasWithScope() {
  89         for (ScriptObject obj = this; obj != null; obj = obj.getProto()) {
  90             if (obj instanceof WithObject) {
  91                 return true;
  92             }
  93         }
  94         return false;
  95     }
  96 
  97     /**
  98      * Get the scope's split method state.
  99      *
 100      * @return current split state
 101      */
 102     public int getSplitState() {
 103         return splitState;
 104     }
 105 
 106     /**
 107      * Set the scope's split method state.
 108      *
 109      * @param state current split state
 110      */
 111     public void setSplitState(final int state) {
 112         splitState = state;
 113     }
 114 
 115     /**
 116      * Get number of {@code Scope} instances created. If not running in debug
 117      * mode this is always 0.
 118      *
 119      * @return number of scope ScriptObjects created
 120      */
 121     public static long getScopeCount() {
 122         return count != null ? count.sum() : 0;
 123     }
 124 
 125     private static void incrementCount() {
 126         if (Context.DEBUG) {
 127             count.increment();
 128         }
 129     }
 130 }