aboutsummaryrefslogtreecommitdiffstats
path: root/trunk/infrastructure/rhino1_7R1/src/org/mozilla/javascript/FunctionObject.java
blob: 8fa4e689482e81b3366a113318f3c53b373068c2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * 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.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-2000
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Norris Boyd
 *   Igor Bukanov
 *   David C. Navas
 *   Ted Neward
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

// API class

package org.mozilla.javascript;

import java.lang.reflect.*;
import java.io.*;

public class FunctionObject extends BaseFunction
{
    static final long serialVersionUID = -5332312783643935019L;

    /**
     * Create a JavaScript function object from a Java method.
     *
     * <p>The <code>member</code> argument must be either a java.lang.reflect.Method
     * or a java.lang.reflect.Constructor and must match one of two forms.<p>
     *
     * The first form is a member with zero or more parameters
     * of the following types: Object, String, boolean, Scriptable,
     * int, or double. The Long type is not supported
     * because the double representation of a long (which is the
     * EMCA-mandated storage type for Numbers) may lose precision.
     * If the member is a Method, the return value must be void or one
     * of the types allowed for parameters.<p>
     *
     * The runtime will perform appropriate conversions based
     * upon the type of the parameter. A parameter type of
     * Object specifies that no conversions are to be done. A parameter
     * of type String will use Context.toString to convert arguments.
     * Similarly, parameters of type double, boolean, and Scriptable
     * will cause Context.toNumber, Context.toBoolean, and
     * Context.toObject, respectively, to be called.<p>
     *
     * If the method is not static, the Java 'this' value will
     * correspond to the JavaScript 'this' value. Any attempt
     * to call the function with a 'this' value that is not
     * of the right Java type will result in an error.<p>
     *
     * The second form is the variable arguments (or "varargs")
     * form. If the FunctionObject will be used as a constructor,
     * the member must have the following parameters
     * <pre>
     *      (Context cx, Object[] args, Function ctorObj,
     *       boolean inNewExpr)</pre>
     * and if it is a Method, be static and return an Object result.<p>
     *
     * Otherwise, if the FunctionObject will <i>not</i> be used to define a
     * constructor, the member must be a static Method with parameters
     *      (Context cx, Scriptable thisObj, Object[] args,
     *       Function funObj) </pre>
     * <pre>
     * and an Object result.<p>
     *
     * When the function varargs form is called as part of a function call,
     * the <code>args</code> parameter contains the
     * arguments, with <code>thisObj</code>
     * set to the JavaScript 'this' value. <code>funObj</code>
     * is the function object for the invoked function.<p>
     *
     * When the constructor varargs form is called or invoked while evaluating
     * a <code>new</code> expression, <code>args</code> contains the
     * arguments, <code>ctorObj</code> refers to this FunctionObject, and
     * <code>inNewExpr</code> is true if and only if  a <code>new</code>
     * expression caused the call. This supports defining a function that
     * has different behavior when called as a constructor than when
     * invoked as a normal function call. (For example, the Boolean
     * constructor, when called as a function,
     * will convert to boolean rather than creating a new object.)<p>
     *
     * @param name the name of the function
     * @param methodOrConstructor a java.lang.reflect.Method or a java.lang.reflect.Constructor
     *                            that defines the object
     * @param scope enclosing scope of function
     * @see org.mozilla.javascript.Scriptable
     */
    public FunctionObject(String name, Member methodOrConstructor,
                          Scriptable scope)
    {
        if (methodOrConstructor instanceof Constructor) {
            member = new MemberBox((Constructor) methodOrConstructor);
            isStatic = true; // well, doesn't take a 'this'
        } else {
            member = new MemberBox((Method) methodOrConstructor);
            isStatic = member.isStatic();
        }
        String methodName = member.getName();
        this.functionName = name;
        Class[] types = member.argTypes;
        int arity = types.length;
        if (arity == 4 && (types[1].isArray() || types[2].isArray())) {
            // Either variable args or an error.
            if (types[1].isArray()) {
                if (!isStatic ||
                    types[0] != ScriptRuntime.ContextClass ||
                    types[1].getComponentType() != ScriptRuntime.ObjectClass ||
                    types[2] != ScriptRuntime.FunctionClass ||
                    types[3] != Boolean.TYPE)
                {
                    throw Context.reportRuntimeError1(
                        "msg.varargs.ctor", methodName);
                }
                parmsLength = VARARGS_CTOR;
            } else {
                if (!isStatic ||
                    types[0] != ScriptRuntime.ContextClass ||
                    types[1] != ScriptRuntime.ScriptableClass ||
                    types[2].getComponentType() != ScriptRuntime.ObjectClass ||
                    types[3] != ScriptRuntime.FunctionClass)
                {
                    throw Context.reportRuntimeError1(
                        "msg.varargs.fun", methodName);
                }
                parmsLength = VARARGS_METHOD;
            }
        } else {
            parmsLength = arity;
            if (arity > 0) {
                typeTags = new byte[arity];
                for (int i = 0; i != arity; ++i) {
                    int tag = getTypeTag(types[i]);
                    if (tag == JAVA_UNSUPPORTED_TYPE) {
                        throw Context.reportRuntimeError2(
                            "msg.bad.parms", types[i].getName(), methodName);
                    }
                    typeTags[i] = (byte)tag;
                }
            }
        }

        if (member.isMethod()) {
            Method method = member.method();
            Class returnType = method.getReturnType();
            if (returnType == Void.TYPE) {
                hasVoidReturn = true;
            } else {
                returnTypeTag = getTypeTag(returnType);
            }
        } else {
            Class ctorType = member.getDeclaringClass();
            if (!ScriptRuntime.ScriptableClass.isAssignableFrom(ctorType)) {
                throw Context.reportRuntimeError1(
                    "msg.bad.ctor.return", ctorType.getName());
            }
        }

        ScriptRuntime.setFunctionProtoAndParent(this, scope);
    }

    /**
     * @return One of <tt>JAVA_*_TYPE</tt> constants to indicate desired type
     *         or {@link #JAVA_UNSUPPORTED_TYPE} if the convertion is not
     *         possible
     */
    public static int getTypeTag(Class type)
    {
        if (type == ScriptRuntime.StringClass)
            return JAVA_STRING_TYPE;
        if (type == ScriptRuntime.IntegerClass || type == Integer.TYPE)
            return JAVA_INT_TYPE;
        if (type == ScriptRuntime.BooleanClass || type == Boolean.TYPE)
            return JAVA_BOOLEAN_TYPE;
        if (type == ScriptRuntime.DoubleClass || type == Double.TYPE)
            return JAVA_DOUBLE_TYPE;
        if (ScriptRuntime.ScriptableClass.isAssignableFrom(type))
            return JAVA_SCRIPTABLE_TYPE;
        if (type == ScriptRuntime.ObjectClass)
            return JAVA_OBJECT_TYPE;

        // Note that the long type is not supported; see the javadoc for
        // the constructor for this class

        return JAVA_UNSUPPORTED_TYPE;
    }

    public static Object convertArg(Context cx, Scriptable scope,
                                    Object arg, int typeTag)
    {
        switch (typeTag) {
          case JAVA_STRING_TYPE:
              if (arg instanceof String)
                return arg;
            return ScriptRuntime.toString(arg);
          case JAVA_INT_TYPE:
              if (arg instanceof Integer)
                return arg;
            return new Integer(ScriptRuntime.toInt32(arg));
          case JAVA_BOOLEAN_TYPE:
              if (arg instanceof Boolean)
                return arg;
            return ScriptRuntime.toBoolean(arg) ? Boolean.TRUE
                                                : Boolean.FALSE;
          case JAVA_DOUBLE_TYPE:
            if (arg instanceof Double)
                return arg;
            return new Double(ScriptRuntime.toNumber(arg));
          case JAVA_SCRIPTABLE_TYPE:
            if (arg instanceof Scriptable)
                return arg;
            return ScriptRuntime.toObject(cx, scope, arg);
          case JAVA_OBJECT_TYPE:
            return arg;
          default:
            throw new IllegalArgumentException();
        }
    }

    /**
     * Return the value defined by  the method used to construct the object
     * (number of parameters of the method, or 1 if the method is a "varargs"
     * form).
     */
    public int getArity() {
        return parmsLength < 0 ? 1 : parmsLength;
    }

    /**
     * Return the same value as {@link #getArity()}.
     */
    public int getLength() {
        return getArity();
    }

    public String getFunctionName()
    {
        return (functionName == null) ? "" : functionName;
    }

    /**
     * Get Java method or constructor this function represent.
     */
    public Member getMethodOrConstructor()
    {
        if (member.isMethod()) {
            return member.method();
        } else {
            return member.ctor();
        }
    }

    static Method findSingleMethod(Method[] methods, String name)
    {
        Method found = null;
        for (int i = 0, N = methods.length; i != N; ++i) {
            Method method = methods[i];
            if (method != null && name.equals(method.getName())) {
                if (found != null) {
                    throw Context.reportRuntimeError2(
                        "msg.no.overload", name,
                        method.getDeclaringClass().getName());
                }
                found = method;
            }
        }
        return found;
    }

    /**
     * Returns all public methods declared by the specified class. This excludes
     * inherited methods.
     *
     * @param clazz the class from which to pull public declared methods
     * @return the public methods declared in the specified class
     * @see Class#getDeclaredMethods()
     */
    static Method[] getMethodList(Class clazz) {
        Method[] methods = null;
        try {
            // getDeclaredMethods may be rejected by the security manager
            // but getMethods is more expensive
            if (!sawSecurityException)
                methods = clazz.getDeclaredMethods();
        } catch (SecurityException e) {
            // If we get an exception once, give up on getDeclaredMethods
            sawSecurityException = true;
        }
        if (methods == null) {
            methods = clazz.getMethods();
        }
        int count = 0;
        for (int i=0; i < methods.length; i++) {
            if (sawSecurityException
                ? methods[i].getDeclaringClass() != clazz
                : !Modifier.isPublic(methods[i].getModifiers()))
            {
                methods[i] = null;
            } else {
                count++;
            }
        }
        Method[] result = new Method[count];
        int j=0;
        for (int i=0; i < methods.length; i++) {
            if (methods[i] != null)
                result[j++] = methods[i];
        }
        return result;
    }

    /**
     * Define this function as a JavaScript constructor.
     * <p>
     * Sets up the "prototype" and "constructor" properties. Also
     * calls setParent and setPrototype with appropriate values.
     * Then adds the function object as a property of the given scope, using
     *      <code>prototype.getClassName()</code>
     * as the name of the property.
     *
     * @param scope the scope in which to define the constructor (typically
     *              the global object)
     * @param prototype the prototype object
     * @see org.mozilla.javascript.Scriptable#setParentScope
     * @see org.mozilla.javascript.Scriptable#setPrototype
     * @see org.mozilla.javascript.Scriptable#getClassName
     */
    public void addAsConstructor(Scriptable scope, Scriptable prototype)
    {
        initAsConstructor(scope, prototype);
        defineProperty(scope, prototype.getClassName(),
                       this, ScriptableObject.DONTENUM);
    }

    void initAsConstructor(Scriptable scope, Scriptable prototype)
    {
        ScriptRuntime.setFunctionProtoAndParent(this, scope);
        setImmunePrototypeProperty(prototype);

        prototype.setParentScope(this);

        defineProperty(prototype, "constructor", this,
                       ScriptableObject.DONTENUM  |
                       ScriptableObject.PERMANENT |
                       ScriptableObject.READONLY);
        setParentScope(scope);
    }

    /**
     * @deprecated Use {@link #getTypeTag(Class)}
     * and {@link #convertArg(Context, Scriptable, Object, int)}
     * for type convertion.
     */
    public static Object convertArg(Context cx, Scriptable scope,
                                    Object arg, Class desired)
    {
        int tag = getTypeTag(desired);
        if (tag == JAVA_UNSUPPORTED_TYPE) {
            throw Context.reportRuntimeError1
                ("msg.cant.convert", desired.getName());
        }
        return convertArg(cx, scope, arg, tag);
    }

    /**
     * Performs conversions on argument types if needed and
     * invokes the underlying Java method or constructor.
     * <p>
     * Implements Function.call.
     *
     * @see org.mozilla.javascript.Function#call(
     *          Context, Scriptable, Scriptable, Object[])
     */
    public Object call(Context cx, Scriptable scope, Scriptable thisObj,
                       Object[] args)
    {
        Object result;
        boolean checkMethodResult = false;

        if (parmsLength < 0) {
            if (parmsLength == VARARGS_METHOD) {
                Object[] invokeArgs = { cx, thisObj, args, this };
                result = member.invoke(null, invokeArgs);
                checkMethodResult = true;
            } else {
                boolean inNewExpr = (thisObj == null);
                Boolean b = inNewExpr ? Boolean.TRUE : Boolean.FALSE;
                Object[] invokeArgs = { cx, args, this, b };
                result = (member.isCtor())
                         ? member.newInstance(invokeArgs)
                         : member.invoke(null, invokeArgs);
            }

        } else {
            if (!isStatic) {
                Class clazz = member.getDeclaringClass();
                if (!clazz.isInstance(thisObj)) {
                    boolean compatible = false;
                    if (thisObj == scope) {
                        Scriptable parentScope = getParentScope();
                        if (scope != parentScope) {
                            // Call with dynamic scope for standalone function,
                            // use parentScope as thisObj
                            compatible = clazz.isInstance(parentScope);
                            if (compatible) {
                                thisObj = parentScope;
                            }
                        }
                    }
                    if (!compatible) {
                        // Couldn't find an object to call this on.
                        throw ScriptRuntime.typeError1("msg.incompat.call",
                                                       functionName);
                    }
                }
            }

            Object[] invokeArgs;
            if (parmsLength == args.length) {
                // Do not allocate new argument array if java arguments are
                // the same as the original js ones.
                invokeArgs = args;
                for (int i = 0; i != parmsLength; ++i) {
                    Object arg = args[i];
                    Object converted = convertArg(cx, scope, arg, typeTags[i]);
                    if (arg != converted) {
                        if (invokeArgs == args) {
                            invokeArgs = args.clone();
                        }
                        invokeArgs[i] = converted;
                    }
                }
            } else if (parmsLength == 0) {
                invokeArgs = ScriptRuntime.emptyArgs;
            } else {
                invokeArgs = new Object[parmsLength];
                for (int i = 0; i != parmsLength; ++i) {
                    Object arg = (i < args.length)
                                 ? args[i]
                                 : Undefined.instance;
                    invokeArgs[i] = convertArg(cx, scope, arg, typeTags[i]);
                }
            }

            if (member.isMethod()) {
                result = member.invoke(thisObj, invokeArgs);
                checkMethodResult = true;
            } else {
                result = member.newInstance(invokeArgs);
            }

        }

        if (checkMethodResult) {
            if (hasVoidReturn) {
                result = Undefined.instance;
            } else if (returnTypeTag == JAVA_UNSUPPORTED_TYPE) {
                result = cx.getWrapFactory().wrap(cx, scope, result, null);
            }
            // XXX: the code assumes that if returnTypeTag == JAVA_OBJECT_TYPE
            // then the Java method did a proper job of converting the
            // result to JS primitive or Scriptable to avoid
            // potentially costly Context.javaToJS call.
        }

        return result;
    }

    /**
     * Return new {@link Scriptable} instance using the default
     * constructor for the class of the underlying Java method.
     * Return null to indicate that the call method should be used to create
     * new objects.
     */
    public Scriptable createObject(Context cx, Scriptable scope) {
        if (member.isCtor() || parmsLength == VARARGS_CTOR) {
            return null;
        }
        Scriptable result;
        try {
            result = (Scriptable) member.getDeclaringClass().newInstance();
        } catch (Exception ex) {
            throw Context.throwAsScriptRuntimeEx(ex);
        }

        result.setPrototype(getClassPrototype());
        result.setParentScope(getParentScope());
        return result;
    }

    boolean isVarArgsMethod() {
        return parmsLength == VARARGS_METHOD;
    }

    boolean isVarArgsConstructor() {
        return parmsLength == VARARGS_CTOR;
    }

    private void readObject(ObjectInputStream in)
        throws IOException, ClassNotFoundException
    {
        in.defaultReadObject();
        if (parmsLength > 0) {
            Class[] types = member.argTypes;
            typeTags = new byte[parmsLength];
            for (int i = 0; i != parmsLength; ++i) {
                typeTags[i] = (byte)getTypeTag(types[i]);
            }
        }
        if (member.isMethod()) {
            Method method = member.method();
            Class returnType = method.getReturnType();
            if (returnType == Void.TYPE) {
                hasVoidReturn = true;
            } else {
                returnTypeTag = getTypeTag(returnType);
            }
        }
    }

    private static final short VARARGS_METHOD = -1;
    private static final short VARARGS_CTOR =   -2;

    private static boolean sawSecurityException;

    public static final int JAVA_UNSUPPORTED_TYPE = 0;
    public static final int JAVA_STRING_TYPE      = 1;
    public static final int JAVA_INT_TYPE         = 2;
    public static final int JAVA_BOOLEAN_TYPE     = 3;
    public static final int JAVA_DOUBLE_TYPE      = 4;
    public static final int JAVA_SCRIPTABLE_TYPE  = 5;
    public static final int JAVA_OBJECT_TYPE      = 6;

    MemberBox member;
    private String functionName;
    private transient byte[] typeTags;
    private int parmsLength;
    private transient boolean hasVoidReturn;
    private transient int returnTypeTag;
    private boolean isStatic;
}