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25 
26 package jdk.nashorn.internal.codegen;
27 
28 import static jdk.nashorn.internal.runtime.arrays.ArrayIndex.getArrayIndex;
29 import static jdk.nashorn.internal.runtime.arrays.ArrayIndex.isValidArrayIndex;
30 
31 import java.util.ArrayList;
32 import java.util.List;
33 import jdk.nashorn.internal.ir.Symbol;
34 import jdk.nashorn.internal.runtime.AccessorProperty;
35 import jdk.nashorn.internal.runtime.Property;
36 import jdk.nashorn.internal.runtime.PropertyMap;
37 import jdk.nashorn.internal.runtime.ScriptObject;
38 import jdk.nashorn.internal.runtime.SpillProperty;
39 
40 /**
41  * Class that creates PropertyMap sent to script object constructors.
42  * @param <T> value type for tuples, e.g. Symbol
43  */
44 public class MapCreator<T> {
45     /** Object structure for objects associated with this map */
46     private final Class<?> structure;
47 
48     /** key set for object map */
49     private final List<MapTuple<T>> tuples;
50 
51     /**
52      * Constructor
53      *
54      * @param structure structure to generate map for (a JO subclass)
55      * @param tuples    list of tuples for map
56      */
MapCreator(final Class<? extends ScriptObject> structure, final List<MapTuple<T>> tuples)57     MapCreator(final Class<? extends ScriptObject> structure, final List<MapTuple<T>> tuples) {
58         this.structure = structure;
59         this.tuples    = tuples;
60     }
61 
62     /**
63      * Constructs a property map based on a set of fields.
64      *
65      * @param hasArguments  does the created object have an "arguments" property
66      * @param fieldCount    Number of fields in use.
67      * @param fieldMaximum  Number of fields available.
68      * @param evalCode      is this property map created for 'eval' code?
69      * @return New map populated with accessor properties.
70      */
makeFieldMap(final boolean hasArguments, final boolean dualFields, final int fieldCount, final int fieldMaximum, final boolean evalCode)71     PropertyMap makeFieldMap(final boolean hasArguments, final boolean dualFields, final int fieldCount, final int fieldMaximum, final boolean evalCode) {
72         final List<Property> properties = new ArrayList<>();
73         assert tuples != null;
74 
75         for (final MapTuple<T> tuple : tuples) {
76             final String   key         = tuple.key;
77             final Symbol   symbol      = tuple.symbol;
78             final Class<?> initialType = dualFields ? tuple.getValueType() : Object.class;
79 
80             if (symbol != null && !isValidArrayIndex(getArrayIndex(key))) {
81                 final int      flags    = getPropertyFlags(symbol, hasArguments, evalCode, dualFields);
82                 final Property property = new AccessorProperty(
83                         key,
84                         flags,
85                         structure,
86                         symbol.getFieldIndex(),
87                         initialType);
88                 properties.add(property);
89             }
90         }
91 
92         return PropertyMap.newMap(properties, structure.getName(), fieldCount, fieldMaximum, 0);
93     }
94 
makeSpillMap(final boolean hasArguments, final boolean dualFields)95     PropertyMap makeSpillMap(final boolean hasArguments, final boolean dualFields) {
96         final List<Property> properties = new ArrayList<>();
97         int spillIndex = 0;
98         assert tuples != null;
99 
100         for (final MapTuple<T> tuple : tuples) {
101             final String key    = tuple.key;
102             final Symbol symbol = tuple.symbol;
103             final Class<?> initialType = dualFields ? tuple.getValueType() : Object.class;
104 
105             if (symbol != null && !isValidArrayIndex(getArrayIndex(key))) {
106                 final int flags = getPropertyFlags(symbol, hasArguments, false, dualFields);
107                 properties.add(
108                         new SpillProperty(
109                                 key,
110                                 flags,
111                                 spillIndex++,
112                                 initialType));
113             }
114         }
115 
116         return PropertyMap.newMap(properties, structure.getName(), 0, 0, spillIndex);
117     }
118 
119     /**
120      * Compute property flags given local state of a field. May be overridden and extended,
121      *
122      * @param symbol       symbol to check
123      * @param hasArguments does the created object have an "arguments" property
124      *
125      * @return flags to use for fields
126      */
getPropertyFlags(final Symbol symbol, final boolean hasArguments, final boolean evalCode, final boolean dualFields)127     static int getPropertyFlags(final Symbol symbol, final boolean hasArguments, final boolean evalCode, final boolean dualFields) {
128         int flags = 0;
129 
130         if (symbol.isParam()) {
131             flags |= Property.IS_PARAMETER;
132         }
133 
134         if (hasArguments) {
135             flags |= Property.HAS_ARGUMENTS;
136         }
137 
138         // See ECMA 5.1 10.5 Declaration Binding Instantiation.
139         // Step 2  If code is eval code, then let configurableBindings
140         // be true else let configurableBindings be false.
141         // We have to make vars, functions declared in 'eval' code
142         // configurable. But vars, functions from any other code is
143         // not configurable.
144         if (symbol.isScope() && !evalCode) {
145             flags |= Property.NOT_CONFIGURABLE;
146         }
147 
148         if (symbol.isFunctionDeclaration()) {
149             flags |= Property.IS_FUNCTION_DECLARATION;
150         }
151 
152         if (symbol.isConst()) {
153             flags |= Property.NOT_WRITABLE;
154         }
155 
156         if (symbol.isBlockScoped()) {
157             flags |= Property.IS_LEXICAL_BINDING;
158         }
159 
160         // Mark symbol as needing declaration. Access before declaration will throw a ReferenceError.
161         if (symbol.isBlockScoped() && symbol.isScope()) {
162             flags |= Property.NEEDS_DECLARATION;
163         }
164 
165         if (dualFields) {
166             flags |= Property.DUAL_FIELDS;
167         }
168 
169         return flags;
170     }
171 }
172