1 | /* |
2 | * Copyright 2003-2006 Sun Microsystems, Inc. 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. Sun designates this |
8 | * particular file as subject to the "Classpath" exception as provided |
9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
23 | * have any questions. |
24 | */ |
25 | |
26 | package com.sun.tools.javac.code; |
27 | |
28 | import java.util.*; |
29 | |
30 | import com.sun.tools.javac.util.*; |
31 | import com.sun.tools.javac.util.List; |
32 | |
33 | import com.sun.tools.javac.jvm.ClassReader; |
34 | import com.sun.tools.javac.comp.Infer; |
35 | import com.sun.tools.javac.comp.Check; |
36 | |
37 | import static com.sun.tools.javac.code.Type.*; |
38 | import static com.sun.tools.javac.code.TypeTags.*; |
39 | import static com.sun.tools.javac.code.Symbol.*; |
40 | import static com.sun.tools.javac.code.Flags.*; |
41 | import static com.sun.tools.javac.code.BoundKind.*; |
42 | import static com.sun.tools.javac.util.ListBuffer.lb; |
43 | |
44 | /** |
45 | * Utility class containing various operations on types. |
46 | * |
47 | * <p>Unless other names are more illustrative, the following naming |
48 | * conventions should be observed in this file: |
49 | * |
50 | * <dl> |
51 | * <dt>t</dt> |
52 | * <dd>If the first argument to an operation is a type, it should be named t.</dd> |
53 | * <dt>s</dt> |
54 | * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd> |
55 | * <dt>ts</dt> |
56 | * <dd>If an operations takes a list of types, the first should be named ts.</dd> |
57 | * <dt>ss</dt> |
58 | * <dd>A second list of types should be named ss.</dd> |
59 | * </dl> |
60 | * |
61 | * <p><b>This is NOT part of any API supported by Sun Microsystems. |
62 | * If you write code that depends on this, you do so at your own risk. |
63 | * This code and its internal interfaces are subject to change or |
64 | * deletion without notice.</b> |
65 | */ |
66 | public class Types { |
67 | protected static final Context.Key<Types> typesKey = |
68 | new Context.Key<Types>(); |
69 | |
70 | final Symtab syms; |
71 | final Name.Table names; |
72 | final boolean allowBoxing; |
73 | final ClassReader reader; |
74 | final Source source; |
75 | final Check chk; |
76 | List<Warner> warnStack = List.nil(); |
77 | final Name capturedName; |
78 | |
79 | // <editor-fold defaultstate="collapsed" desc="Instantiating"> |
80 | public static Types instance(Context context) { |
81 | Types instance = context.get(typesKey); |
82 | if (instance == null) |
83 | instance = new Types(context); |
84 | return instance; |
85 | } |
86 | |
87 | protected Types(Context context) { |
88 | context.put(typesKey, this); |
89 | syms = Symtab.instance(context); |
90 | names = Name.Table.instance(context); |
91 | allowBoxing = Source.instance(context).allowBoxing(); |
92 | reader = ClassReader.instance(context); |
93 | source = Source.instance(context); |
94 | chk = Check.instance(context); |
95 | capturedName = names.fromString("<captured wildcard>"); |
96 | } |
97 | // </editor-fold> |
98 | |
99 | // <editor-fold defaultstate="collapsed" desc="upperBound"> |
100 | /** |
101 | * The "rvalue conversion".<br> |
102 | * The upper bound of most types is the type |
103 | * itself. Wildcards, on the other hand have upper |
104 | * and lower bounds. |
105 | * @param t a type |
106 | * @return the upper bound of the given type |
107 | */ |
108 | public Type upperBound(Type t) { |
109 | return upperBound.visit(t); |
110 | } |
111 | // where |
112 | private final MapVisitor<Void> upperBound = new MapVisitor<Void>() { |
113 | |
114 | @Override |
115 | public Type visitWildcardType(WildcardType t, Void ignored) { |
116 | if (t.isSuperBound()) |
117 | return t.bound == null ? syms.objectType : t.bound.bound; |
118 | else |
119 | return visit(t.type); |
120 | } |
121 | |
122 | @Override |
123 | public Type visitCapturedType(CapturedType t, Void ignored) { |
124 | return visit(t.bound); |
125 | } |
126 | }; |
127 | // </editor-fold> |
128 | |
129 | // <editor-fold defaultstate="collapsed" desc="lowerBound"> |
130 | /** |
131 | * The "lvalue conversion".<br> |
132 | * The lower bound of most types is the type |
133 | * itself. Wildcards, on the other hand have upper |
134 | * and lower bounds. |
135 | * @param t a type |
136 | * @return the lower bound of the given type |
137 | */ |
138 | public Type lowerBound(Type t) { |
139 | return lowerBound.visit(t); |
140 | } |
141 | // where |
142 | private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() { |
143 | |
144 | @Override |
145 | public Type visitWildcardType(WildcardType t, Void ignored) { |
146 | return t.isExtendsBound() ? syms.botType : visit(t.type); |
147 | } |
148 | |
149 | @Override |
150 | public Type visitCapturedType(CapturedType t, Void ignored) { |
151 | return visit(t.getLowerBound()); |
152 | } |
153 | }; |
154 | // </editor-fold> |
155 | |
156 | // <editor-fold defaultstate="collapsed" desc="isUnbounded"> |
157 | /** |
158 | * Checks that all the arguments to a class are unbounded |
159 | * wildcards or something else that doesn't make any restrictions |
160 | * on the arguments. If a class isUnbounded, a raw super- or |
161 | * subclass can be cast to it without a warning. |
162 | * @param t a type |
163 | * @return true iff the given type is unbounded or raw |
164 | */ |
165 | public boolean isUnbounded(Type t) { |
166 | return isUnbounded.visit(t); |
167 | } |
168 | // where |
169 | private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() { |
170 | |
171 | public Boolean visitType(Type t, Void ignored) { |
172 | return true; |
173 | } |
174 | |
175 | @Override |
176 | public Boolean visitClassType(ClassType t, Void ignored) { |
177 | List<Type> parms = t.tsym.type.allparams(); |
178 | List<Type> args = t.allparams(); |
179 | while (parms.nonEmpty()) { |
180 | WildcardType unb = new WildcardType(syms.objectType, |
181 | BoundKind.UNBOUND, |
182 | syms.boundClass, |
183 | (TypeVar)parms.head); |
184 | if (!containsType(args.head, unb)) |
185 | return false; |
186 | parms = parms.tail; |
187 | args = args.tail; |
188 | } |
189 | return true; |
190 | } |
191 | }; |
192 | // </editor-fold> |
193 | |
194 | // <editor-fold defaultstate="collapsed" desc="asSub"> |
195 | /** |
196 | * Return the least specific subtype of t that starts with symbol |
197 | * sym. If none exists, return null. The least specific subtype |
198 | * is determined as follows: |
199 | * |
200 | * <p>If there is exactly one parameterized instance of sym that is a |
201 | * subtype of t, that parameterized instance is returned.<br> |
202 | * Otherwise, if the plain type or raw type `sym' is a subtype of |
203 | * type t, the type `sym' itself is returned. Otherwise, null is |
204 | * returned. |
205 | */ |
206 | public Type asSub(Type t, Symbol sym) { |
207 | return asSub.visit(t, sym); |
208 | } |
209 | // where |
210 | private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() { |
211 | |
212 | public Type visitType(Type t, Symbol sym) { |
213 | return null; |
214 | } |
215 | |
216 | @Override |
217 | public Type visitClassType(ClassType t, Symbol sym) { |
218 | if (t.tsym == sym) |
219 | return t; |
220 | Type base = asSuper(sym.type, t.tsym); |
221 | if (base == null) |
222 | return null; |
223 | ListBuffer<Type> from = new ListBuffer<Type>(); |
224 | ListBuffer<Type> to = new ListBuffer<Type>(); |
225 | try { |
226 | adapt(base, t, from, to); |
227 | } catch (AdaptFailure ex) { |
228 | return null; |
229 | } |
230 | Type res = subst(sym.type, from.toList(), to.toList()); |
231 | if (!isSubtype(res, t)) |
232 | return null; |
233 | ListBuffer<Type> openVars = new ListBuffer<Type>(); |
234 | for (List<Type> l = sym.type.allparams(); |
235 | l.nonEmpty(); l = l.tail) |
236 | if (res.contains(l.head) && !t.contains(l.head)) |
237 | openVars.append(l.head); |
238 | if (openVars.nonEmpty()) { |
239 | if (t.isRaw()) { |
240 | // The subtype of a raw type is raw |
241 | res = erasure(res); |
242 | } else { |
243 | // Unbound type arguments default to ? |
244 | List<Type> opens = openVars.toList(); |
245 | ListBuffer<Type> qs = new ListBuffer<Type>(); |
246 | for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) { |
247 | qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head)); |
248 | } |
249 | res = subst(res, opens, qs.toList()); |
250 | } |
251 | } |
252 | return res; |
253 | } |
254 | |
255 | @Override |
256 | public Type visitErrorType(ErrorType t, Symbol sym) { |
257 | return t; |
258 | } |
259 | }; |
260 | // </editor-fold> |
261 | |
262 | // <editor-fold defaultstate="collapsed" desc="isConvertible"> |
263 | /** |
264 | * Is t a subtype of or convertiable via boxing/unboxing |
265 | * convertions to s? |
266 | */ |
267 | public boolean isConvertible(Type t, Type s, Warner warn) { |
268 | boolean tPrimitive = t.isPrimitive(); |
269 | boolean sPrimitive = s.isPrimitive(); |
270 | if (tPrimitive == sPrimitive) |
271 | return isSubtypeUnchecked(t, s, warn); |
272 | if (!allowBoxing) return false; |
273 | return tPrimitive |
274 | ? isSubtype(boxedClass(t).type, s) |
275 | : isSubtype(unboxedType(t), s); |
276 | } |
277 | |
278 | /** |
279 | * Is t a subtype of or convertiable via boxing/unboxing |
280 | * convertions to s? |
281 | */ |
282 | public boolean isConvertible(Type t, Type s) { |
283 | return isConvertible(t, s, Warner.noWarnings); |
284 | } |
285 | // </editor-fold> |
286 | |
287 | // <editor-fold defaultstate="collapsed" desc="isSubtype"> |
288 | /** |
289 | * Is t an unchecked subtype of s? |
290 | */ |
291 | public boolean isSubtypeUnchecked(Type t, Type s) { |
292 | return isSubtypeUnchecked(t, s, Warner.noWarnings); |
293 | } |
294 | /** |
295 | * Is t an unchecked subtype of s? |
296 | */ |
297 | public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) { |
298 | if (t.tag == ARRAY && s.tag == ARRAY) { |
299 | return (((ArrayType)t).elemtype.tag <= lastBaseTag) |
300 | ? isSameType(elemtype(t), elemtype(s)) |
301 | : isSubtypeUnchecked(elemtype(t), elemtype(s), warn); |
302 | } else if (isSubtype(t, s)) { |
303 | return true; |
304 | } else if (!s.isRaw()) { |
305 | Type t2 = asSuper(t, s.tsym); |
306 | if (t2 != null && t2.isRaw()) { |
307 | if (isReifiable(s)) |
308 | warn.silentUnchecked(); |
309 | else |
310 | warn.warnUnchecked(); |
311 | return true; |
312 | } |
313 | } |
314 | return false; |
315 | } |
316 | |
317 | /** |
318 | * Is t a subtype of s?<br> |
319 | * (not defined for Method and ForAll types) |
320 | */ |
321 | final public boolean isSubtype(Type t, Type s) { |
322 | return isSubtype(t, s, true); |
323 | } |
324 | final public boolean isSubtypeNoCapture(Type t, Type s) { |
325 | return isSubtype(t, s, false); |
326 | } |
327 | public boolean isSubtype(Type t, Type s, boolean capture) { |
328 | if (t == s) |
329 | return true; |
330 | |
331 | if (s.tag >= firstPartialTag) |
332 | return isSuperType(s, t); |
333 | |
334 | Type lower = lowerBound(s); |
335 | if (s != lower) |
336 | return isSubtype(capture ? capture(t) : t, lower, false); |
337 | |
338 | return isSubtype.visit(capture ? capture(t) : t, s); |
339 | } |
340 | // where |
341 | private TypeRelation isSubtype = new TypeRelation() |
342 | { |
343 | public Boolean visitType(Type t, Type s) { |
344 | switch (t.tag) { |
345 | case BYTE: case CHAR: |
346 | return (t.tag == s.tag || |
347 | t.tag + 2 <= s.tag && s.tag <= DOUBLE); |
348 | case SHORT: case INT: case LONG: case FLOAT: case DOUBLE: |
349 | return t.tag <= s.tag && s.tag <= DOUBLE; |
350 | case BOOLEAN: case VOID: |
351 | return t.tag == s.tag; |
352 | case TYPEVAR: |
353 | return isSubtypeNoCapture(t.getUpperBound(), s); |
354 | case BOT: |
355 | return |
356 | s.tag == BOT || s.tag == CLASS || |
357 | s.tag == ARRAY || s.tag == TYPEVAR; |
358 | case NONE: |
359 | return false; |
360 | default: |
361 | throw new AssertionError("isSubtype " + t.tag); |
362 | } |
363 | } |
364 | |
365 | private Set<TypePair> cache = new HashSet<TypePair>(); |
366 | |
367 | private boolean containsTypeRecursive(Type t, Type s) { |
368 | TypePair pair = new TypePair(t, s); |
369 | if (cache.add(pair)) { |
370 | try { |
371 | return containsType(t.getTypeArguments(), |
372 | s.getTypeArguments()); |
373 | } finally { |
374 | cache.remove(pair); |
375 | } |
376 | } else { |
377 | return containsType(t.getTypeArguments(), |
378 | rewriteSupers(s).getTypeArguments()); |
379 | } |
380 | } |
381 | |
382 | private Type rewriteSupers(Type t) { |
383 | if (!t.isParameterized()) |
384 | return t; |
385 | ListBuffer<Type> from = lb(); |
386 | ListBuffer<Type> to = lb(); |
387 | adaptSelf(t, from, to); |
388 | if (from.isEmpty()) |
389 | return t; |
390 | ListBuffer<Type> rewrite = lb(); |
391 | boolean changed = false; |
392 | for (Type orig : to.toList()) { |
393 | Type s = rewriteSupers(orig); |
394 | if (s.isSuperBound() && !s.isExtendsBound()) { |
395 | s = new WildcardType(syms.objectType, |
396 | BoundKind.UNBOUND, |
397 | syms.boundClass); |
398 | changed = true; |
399 | } else if (s != orig) { |
400 | s = new WildcardType(upperBound(s), |
401 | BoundKind.EXTENDS, |
402 | syms.boundClass); |
403 | changed = true; |
404 | } |
405 | rewrite.append(s); |
406 | } |
407 | if (changed) |
408 | return subst(t.tsym.type, from.toList(), rewrite.toList()); |
409 | else |
410 | return t; |
411 | } |
412 | |
413 | @Override |
414 | public Boolean visitClassType(ClassType t, Type s) { |
415 | Type sup = asSuper(t, s.tsym); |
416 | return sup != null |
417 | && sup.tsym == s.tsym |
418 | // You're not allowed to write |
419 | // Vector<Object> vec = new Vector<String>(); |
420 | // But with wildcards you can write |
421 | // Vector<? extends Object> vec = new Vector<String>(); |
422 | // which means that subtype checking must be done |
423 | // here instead of same-type checking (via containsType). |
424 | && (!s.isParameterized() || containsTypeRecursive(s, sup)) |
425 | && isSubtypeNoCapture(sup.getEnclosingType(), |
426 | s.getEnclosingType()); |
427 | } |
428 | |
429 | @Override |
430 | public Boolean visitArrayType(ArrayType t, Type s) { |
431 | if (s.tag == ARRAY) { |
432 | if (t.elemtype.tag <= lastBaseTag) |
433 | return isSameType(t.elemtype, elemtype(s)); |
434 | else |
435 | return isSubtypeNoCapture(t.elemtype, elemtype(s)); |
436 | } |
437 | |
438 | if (s.tag == CLASS) { |
439 | Name sname = s.tsym.getQualifiedName(); |
440 | return sname == names.java_lang_Object |
441 | || sname == names.java_lang_Cloneable |
442 | || sname == names.java_io_Serializable; |
443 | } |
444 | |
445 | return false; |
446 | } |
447 | |
448 | @Override |
449 | public Boolean visitUndetVar(UndetVar t, Type s) { |
450 | //todo: test against origin needed? or replace with substitution? |
451 | if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) |
452 | return true; |
453 | |
454 | if (t.inst != null) |
455 | return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"? |
456 | |
457 | t.hibounds = t.hibounds.prepend(s); |
458 | return true; |
459 | } |
460 | |
461 | @Override |
462 | public Boolean visitErrorType(ErrorType t, Type s) { |
463 | return true; |
464 | } |
465 | }; |
466 | |
467 | /** |
468 | * Is t a subtype of every type in given list `ts'?<br> |
469 | * (not defined for Method and ForAll types)<br> |
470 | * Allows unchecked conversions. |
471 | */ |
472 | public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) { |
473 | for (List<Type> l = ts; l.nonEmpty(); l = l.tail) |
474 | if (!isSubtypeUnchecked(t, l.head, warn)) |
475 | return false; |
476 | return true; |
477 | } |
478 | |
479 | /** |
480 | * Are corresponding elements of ts subtypes of ss? If lists are |
481 | * of different length, return false. |
482 | */ |
483 | public boolean isSubtypes(List<Type> ts, List<Type> ss) { |
484 | while (ts.tail != null && ss.tail != null |
485 | /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && |
486 | isSubtype(ts.head, ss.head)) { |
487 | ts = ts.tail; |
488 | ss = ss.tail; |
489 | } |
490 | return ts.tail == null && ss.tail == null; |
491 | /*inlined: ts.isEmpty() && ss.isEmpty();*/ |
492 | } |
493 | |
494 | /** |
495 | * Are corresponding elements of ts subtypes of ss, allowing |
496 | * unchecked conversions? If lists are of different length, |
497 | * return false. |
498 | **/ |
499 | public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) { |
500 | while (ts.tail != null && ss.tail != null |
501 | /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && |
502 | isSubtypeUnchecked(ts.head, ss.head, warn)) { |
503 | ts = ts.tail; |
504 | ss = ss.tail; |
505 | } |
506 | return ts.tail == null && ss.tail == null; |
507 | /*inlined: ts.isEmpty() && ss.isEmpty();*/ |
508 | } |
509 | // </editor-fold> |
510 | |
511 | // <editor-fold defaultstate="collapsed" desc="isSuperType"> |
512 | /** |
513 | * Is t a supertype of s? |
514 | */ |
515 | public boolean isSuperType(Type t, Type s) { |
516 | switch (t.tag) { |
517 | case ERROR: |
518 | return true; |
519 | case UNDETVAR: { |
520 | UndetVar undet = (UndetVar)t; |
521 | if (t == s || |
522 | undet.qtype == s || |
523 | s.tag == ERROR || |
524 | s.tag == BOT) return true; |
525 | if (undet.inst != null) |
526 | return isSubtype(s, undet.inst); |
527 | undet.lobounds = undet.lobounds.prepend(s); |
528 | return true; |
529 | } |
530 | default: |
531 | return isSubtype(s, t); |
532 | } |
533 | } |
534 | // </editor-fold> |
535 | |
536 | // <editor-fold defaultstate="collapsed" desc="isSameType"> |
537 | /** |
538 | * Are corresponding elements of the lists the same type? If |
539 | * lists are of different length, return false. |
540 | */ |
541 | public boolean isSameTypes(List<Type> ts, List<Type> ss) { |
542 | while (ts.tail != null && ss.tail != null |
543 | /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && |
544 | isSameType(ts.head, ss.head)) { |
545 | ts = ts.tail; |
546 | ss = ss.tail; |
547 | } |
548 | return ts.tail == null && ss.tail == null; |
549 | /*inlined: ts.isEmpty() && ss.isEmpty();*/ |
550 | } |
551 | |
552 | /** |
553 | * Is t the same type as s? |
554 | */ |
555 | public boolean isSameType(Type t, Type s) { |
556 | return isSameType.visit(t, s); |
557 | } |
558 | // where |
559 | private TypeRelation isSameType = new TypeRelation() { |
560 | |
561 | public Boolean visitType(Type t, Type s) { |
562 | if (t == s) |
563 | return true; |
564 | |
565 | if (s.tag >= firstPartialTag) |
566 | return visit(s, t); |
567 | |
568 | switch (t.tag) { |
569 | case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: |
570 | case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE: |
571 | return t.tag == s.tag; |
572 | case TYPEVAR: |
573 | return s.isSuperBound() |
574 | && !s.isExtendsBound() |
575 | && visit(t, upperBound(s)); |
576 | default: |
577 | throw new AssertionError("isSameType " + t.tag); |
578 | } |
579 | } |
580 | |
581 | @Override |
582 | public Boolean visitWildcardType(WildcardType t, Type s) { |
583 | if (s.tag >= firstPartialTag) |
584 | return visit(s, t); |
585 | else |
586 | return false; |
587 | } |
588 | |
589 | @Override |
590 | public Boolean visitClassType(ClassType t, Type s) { |
591 | if (t == s) |
592 | return true; |
593 | |
594 | if (s.tag >= firstPartialTag) |
595 | return visit(s, t); |
596 | |
597 | if (s.isSuperBound() && !s.isExtendsBound()) |
598 | return visit(t, upperBound(s)) && visit(t, lowerBound(s)); |
599 | |
600 | if (t.isCompound() && s.isCompound()) { |
601 | if (!visit(supertype(t), supertype(s))) |
602 | return false; |
603 | |
604 | HashSet<SingletonType> set = new HashSet<SingletonType>(); |
605 | for (Type x : interfaces(t)) |
606 | set.add(new SingletonType(x)); |
607 | for (Type x : interfaces(s)) { |
608 | if (!set.remove(new SingletonType(x))) |
609 | return false; |
610 | } |
611 | return (set.size() == 0); |
612 | } |
613 | return t.tsym == s.tsym |
614 | && visit(t.getEnclosingType(), s.getEnclosingType()) |
615 | && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments()); |
616 | } |
617 | |
618 | @Override |
619 | public Boolean visitArrayType(ArrayType t, Type s) { |
620 | if (t == s) |
621 | return true; |
622 | |
623 | if (s.tag >= firstPartialTag) |
624 | return visit(s, t); |
625 | |
626 | return s.tag == ARRAY |
627 | && containsTypeEquivalent(t.elemtype, elemtype(s)); |
628 | } |
629 | |
630 | @Override |
631 | public Boolean visitMethodType(MethodType t, Type s) { |
632 | // isSameType for methods does not take thrown |
633 | // exceptions into account! |
634 | return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType()); |
635 | } |
636 | |
637 | @Override |
638 | public Boolean visitPackageType(PackageType t, Type s) { |
639 | return t == s; |
640 | } |
641 | |
642 | @Override |
643 | public Boolean visitForAll(ForAll t, Type s) { |
644 | if (s.tag != FORALL) |
645 | return false; |
646 | |
647 | ForAll forAll = (ForAll)s; |
648 | return hasSameBounds(t, forAll) |
649 | && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); |
650 | } |
651 | |
652 | @Override |
653 | public Boolean visitUndetVar(UndetVar t, Type s) { |
654 | if (s.tag == WILDCARD) |
655 | // FIXME, this might be leftovers from before capture conversion |
656 | return false; |
657 | |
658 | if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) |
659 | return true; |
660 | |
661 | if (t.inst != null) |
662 | return visit(t.inst, s); |
663 | |
664 | t.inst = fromUnknownFun.apply(s); |
665 | for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) { |
666 | if (!isSubtype(l.head, t.inst)) |
667 | return false; |
668 | } |
669 | for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) { |
670 | if (!isSubtype(t.inst, l.head)) |
671 | return false; |
672 | } |
673 | return true; |
674 | } |
675 | |
676 | @Override |
677 | public Boolean visitErrorType(ErrorType t, Type s) { |
678 | return true; |
679 | } |
680 | }; |
681 | // </editor-fold> |
682 | |
683 | // <editor-fold defaultstate="collapsed" desc="fromUnknownFun"> |
684 | /** |
685 | * A mapping that turns all unknown types in this type to fresh |
686 | * unknown variables. |
687 | */ |
688 | public Mapping fromUnknownFun = new Mapping("fromUnknownFun") { |
689 | public Type apply(Type t) { |
690 | if (t.tag == UNKNOWN) return new UndetVar(t); |
691 | else return t.map(this); |
692 | } |
693 | }; |
694 | // </editor-fold> |
695 | |
696 | // <editor-fold defaultstate="collapsed" desc="Contains Type"> |
697 | public boolean containedBy(Type t, Type s) { |
698 | switch (t.tag) { |
699 | case UNDETVAR: |
700 | if (s.tag == WILDCARD) { |
701 | UndetVar undetvar = (UndetVar)t; |
702 | |
703 | // Because of wildcard capture, s must be on the left |
704 | // hand side of an assignment. Furthermore, t is an |
705 | // underconstrained type variable, for example, one |
706 | // that is only used in the return type of a method. |
707 | // If the type variable is truly underconstrained, it |
708 | // cannot have any low bounds: |
709 | assert undetvar.lobounds.isEmpty() : undetvar; |
710 | |
711 | undetvar.inst = glb(upperBound(s), undetvar.inst); |
712 | return true; |
713 | } else { |
714 | return isSameType(t, s); |
715 | } |
716 | case ERROR: |
717 | return true; |
718 | default: |
719 | return containsType(s, t); |
720 | } |
721 | } |
722 | |
723 | boolean containsType(List<Type> ts, List<Type> ss) { |
724 | while (ts.nonEmpty() && ss.nonEmpty() |
725 | && containsType(ts.head, ss.head)) { |
726 | ts = ts.tail; |
727 | ss = ss.tail; |
728 | } |
729 | return ts.isEmpty() && ss.isEmpty(); |
730 | } |
731 | |
732 | /** |
733 | * Check if t contains s. |
734 | * |
735 | * <p>T contains S if: |
736 | * |
737 | * <p>{@code L(T) <: L(S) && U(S) <: U(T)} |
738 | * |
739 | * <p>This relation is only used by ClassType.isSubtype(), that |
740 | * is, |
741 | * |
742 | * <p>{@code C<S> <: C<T> if T contains S.} |
743 | * |
744 | * <p>Because of F-bounds, this relation can lead to infinite |
745 | * recursion. Thus we must somehow break that recursion. Notice |
746 | * that containsType() is only called from ClassType.isSubtype(). |
747 | * Since the arguments have already been checked against their |
748 | * bounds, we know: |
749 | * |
750 | * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)} |
751 | * |
752 | * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)} |
753 | * |
754 | * @param t a type |
755 | * @param s a type |
756 | */ |
757 | public boolean containsType(Type t, Type s) { |
758 | return containsType.visit(t, s); |
759 | } |
760 | // where |
761 | private TypeRelation containsType = new TypeRelation() { |
762 | |
763 | private Type U(Type t) { |
764 | while (t.tag == WILDCARD) { |
765 | WildcardType w = (WildcardType)t; |
766 | if (w.isSuperBound()) |
767 | return w.bound == null ? syms.objectType : w.bound.bound; |
768 | else |
769 | t = w.type; |
770 | } |
771 | return t; |
772 | } |
773 | |
774 | private Type L(Type t) { |
775 | while (t.tag == WILDCARD) { |
776 | WildcardType w = (WildcardType)t; |
777 | if (w.isExtendsBound()) |
778 | return syms.botType; |
779 | else |
780 | t = w.type; |
781 | } |
782 | return t; |
783 | } |
784 | |
785 | public Boolean visitType(Type t, Type s) { |
786 | if (s.tag >= firstPartialTag) |
787 | return containedBy(s, t); |
788 | else |
789 | return isSameType(t, s); |
790 | } |
791 | |
792 | void debugContainsType(WildcardType t, Type s) { |
793 | System.err.println(); |
794 | System.err.format(" does %s contain %s?%n", t, s); |
795 | System.err.format(" %s U(%s) <: U(%s) %s = %s%n", |
796 | upperBound(s), s, t, U(t), |
797 | t.isSuperBound() |
798 | || isSubtypeNoCapture(upperBound(s), U(t))); |
799 | System.err.format(" %s L(%s) <: L(%s) %s = %s%n", |
800 | L(t), t, s, lowerBound(s), |
801 | t.isExtendsBound() |
802 | || isSubtypeNoCapture(L(t), lowerBound(s))); |
803 | System.err.println(); |
804 | } |
805 | |
806 | @Override |
807 | public Boolean visitWildcardType(WildcardType t, Type s) { |
808 | if (s.tag >= firstPartialTag) |
809 | return containedBy(s, t); |
810 | else { |
811 | // debugContainsType(t, s); |
812 | return isSameWildcard(t, s) |
813 | || isCaptureOf(s, t) |
814 | || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) && |
815 | (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t)))); |
816 | } |
817 | } |
818 | |
819 | @Override |
820 | public Boolean visitUndetVar(UndetVar t, Type s) { |
821 | if (s.tag != WILDCARD) |
822 | return isSameType(t, s); |
823 | else |
824 | return false; |
825 | } |
826 | |
827 | @Override |
828 | public Boolean visitErrorType(ErrorType t, Type s) { |
829 | return true; |
830 | } |
831 | }; |
832 | |
833 | public boolean isCaptureOf(Type s, WildcardType t) { |
834 | if (s.tag != TYPEVAR || !(s instanceof CapturedType)) |
835 | return false; |
836 | return isSameWildcard(t, ((CapturedType)s).wildcard); |
837 | } |
838 | |
839 | public boolean isSameWildcard(WildcardType t, Type s) { |
840 | if (s.tag != WILDCARD) |
841 | return false; |
842 | WildcardType w = (WildcardType)s; |
843 | return w.kind == t.kind && w.type == t.type; |
844 | } |
845 | |
846 | public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) { |
847 | while (ts.nonEmpty() && ss.nonEmpty() |
848 | && containsTypeEquivalent(ts.head, ss.head)) { |
849 | ts = ts.tail; |
850 | ss = ss.tail; |
851 | } |
852 | return ts.isEmpty() && ss.isEmpty(); |
853 | } |
854 | // </editor-fold> |
855 | |
856 | // <editor-fold defaultstate="collapsed" desc="isCastable"> |
857 | public boolean isCastable(Type t, Type s) { |
858 | return isCastable(t, s, Warner.noWarnings); |
859 | } |
860 | |
861 | /** |
862 | * Is t is castable to s?<br> |
863 | * s is assumed to be an erased type.<br> |
864 | * (not defined for Method and ForAll types). |
865 | */ |
866 | public boolean isCastable(Type t, Type s, Warner warn) { |
867 | if (t == s) |
868 | return true; |
869 | |
870 | if (t.isPrimitive() != s.isPrimitive()) |
871 | return allowBoxing && isConvertible(t, s, warn); |
872 | |
873 | if (warn != warnStack.head) { |
874 | try { |
875 | warnStack = warnStack.prepend(warn); |
876 | return isCastable.visit(t, s); |
877 | } finally { |
878 | warnStack = warnStack.tail; |
879 | } |
880 | } else { |
881 | return isCastable.visit(t, s); |
882 | } |
883 | } |
884 | // where |
885 | private TypeRelation isCastable = new TypeRelation() { |
886 | |
887 | public Boolean visitType(Type t, Type s) { |
888 | if (s.tag == ERROR) |
889 | return true; |
890 | |
891 | switch (t.tag) { |
892 | case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: |
893 | case DOUBLE: |
894 | return s.tag <= DOUBLE; |
895 | case BOOLEAN: |
896 | return s.tag == BOOLEAN; |
897 | case VOID: |
898 | return false; |
899 | case BOT: |
900 | return isSubtype(t, s); |
901 | default: |
902 | throw new AssertionError(); |
903 | } |
904 | } |
905 | |
906 | @Override |
907 | public Boolean visitWildcardType(WildcardType t, Type s) { |
908 | return isCastable(upperBound(t), s, warnStack.head); |
909 | } |
910 | |
911 | @Override |
912 | public Boolean visitClassType(ClassType t, Type s) { |
913 | if (s.tag == ERROR || s.tag == BOT) |
914 | return true; |
915 | |
916 | if (s.tag == TYPEVAR) { |
917 | if (isCastable(s.getUpperBound(), t, Warner.noWarnings)) { |
918 | warnStack.head.warnUnchecked(); |
919 | return true; |
920 | } else { |
921 | return false; |
922 | } |
923 | } |
924 | |
925 | if (t.isCompound()) { |
926 | if (!visit(supertype(t), s)) |
927 | return false; |
928 | for (Type intf : interfaces(t)) { |
929 | if (!visit(intf, s)) |
930 | return false; |
931 | } |
932 | return true; |
933 | } |
934 | |
935 | if (s.isCompound()) { |
936 | // call recursively to reuse the above code |
937 | return visitClassType((ClassType)s, t); |
938 | } |
939 | |
940 | if (s.tag == CLASS || s.tag == ARRAY) { |
941 | boolean upcast; |
942 | if ((upcast = isSubtype(erasure(t), erasure(s))) |
943 | || isSubtype(erasure(s), erasure(t))) { |
944 | if (!upcast && s.tag == ARRAY) { |
945 | if (!isReifiable(s)) |
946 | warnStack.head.warnUnchecked(); |
947 | return true; |
948 | } else if (s.isRaw()) { |
949 | return true; |
950 | } else if (t.isRaw()) { |
951 | if (!isUnbounded(s)) |
952 | warnStack.head.warnUnchecked(); |
953 | return true; |
954 | } |
955 | // Assume |a| <: |b| |
956 | final Type a = upcast ? t : s; |
957 | final Type b = upcast ? s : t; |
958 | final boolean HIGH = true; |
959 | final boolean LOW = false; |
960 | final boolean DONT_REWRITE_TYPEVARS = false; |
961 | Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS); |
962 | Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS); |
963 | Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS); |
964 | Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS); |
965 | Type lowSub = asSub(bLow, aLow.tsym); |
966 | Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); |
967 | if (highSub == null) { |
968 | final boolean REWRITE_TYPEVARS = true; |
969 | aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS); |
970 | aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS); |
971 | bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS); |
972 | bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS); |
973 | lowSub = asSub(bLow, aLow.tsym); |
974 | highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); |
975 | } |
976 | if (highSub != null) { |
977 | assert a.tsym == highSub.tsym && a.tsym == lowSub.tsym |
978 | : a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym; |
979 | if (!disjointTypes(aHigh.getTypeArguments(), highSub.getTypeArguments()) |
980 | && !disjointTypes(aHigh.getTypeArguments(), lowSub.getTypeArguments()) |
981 | && !disjointTypes(aLow.getTypeArguments(), highSub.getTypeArguments()) |
982 | && !disjointTypes(aLow.getTypeArguments(), lowSub.getTypeArguments())) { |
983 | if (upcast ? giveWarning(a, highSub) || giveWarning(a, lowSub) |
984 | : giveWarning(highSub, a) || giveWarning(lowSub, a)) |
985 | warnStack.head.warnUnchecked(); |
986 | return true; |
987 | } |
988 | } |
989 | if (isReifiable(s)) |
990 | return isSubtypeUnchecked(a, b); |
991 | else |
992 | return isSubtypeUnchecked(a, b, warnStack.head); |
993 | } |
994 | |
995 | // Sidecast |
996 | if (s.tag == CLASS) { |
997 | if ((s.tsym.flags() & INTERFACE) != 0) { |
998 | return ((t.tsym.flags() & FINAL) == 0) |
999 | ? sideCast(t, s, warnStack.head) |
1000 | : sideCastFinal(t, s, warnStack.head); |
1001 | } else if ((t.tsym.flags() & INTERFACE) != 0) { |
1002 | return ((s.tsym.flags() & FINAL) == 0) |
1003 | ? sideCast(t, s, warnStack.head) |
1004 | : sideCastFinal(t, s, warnStack.head); |
1005 | } else { |
1006 | // unrelated class types |
1007 | return false; |
1008 | } |
1009 | } |
1010 | } |
1011 | return false; |
1012 | } |
1013 | |
1014 | @Override |
1015 | public Boolean visitArrayType(ArrayType t, Type s) { |
1016 | switch (s.tag) { |
1017 | case ERROR: |
1018 | case BOT: |
1019 | return true; |
1020 | case TYPEVAR: |
1021 | if (isCastable(s, t, Warner.noWarnings)) { |
1022 | warnStack.head.warnUnchecked(); |
1023 | return true; |
1024 | } else { |
1025 | return false; |
1026 | } |
1027 | case CLASS: |
1028 | return isSubtype(t, s); |
1029 | case ARRAY: |
1030 | if (elemtype(t).tag <= lastBaseTag) { |
1031 | return elemtype(t).tag == elemtype(s).tag; |
1032 | } else { |
1033 | return visit(elemtype(t), elemtype(s)); |
1034 | } |
1035 | default: |
1036 | return false; |
1037 | } |
1038 | } |
1039 | |
1040 | @Override |
1041 | public Boolean visitTypeVar(TypeVar t, Type s) { |
1042 | switch (s.tag) { |
1043 | case ERROR: |
1044 | case BOT: |
1045 | return true; |
1046 | case TYPEVAR: |
1047 | if (isSubtype(t, s)) { |
1048 | return true; |
1049 | } else if (isCastable(t.bound, s, Warner.noWarnings)) { |
1050 | warnStack.head.warnUnchecked(); |
1051 | return true; |
1052 | } else { |
1053 | return false; |
1054 | } |
1055 | default: |
1056 | return isCastable(t.bound, s, warnStack.head); |
1057 | } |
1058 | } |
1059 | |
1060 | @Override |
1061 | public Boolean visitErrorType(ErrorType t, Type s) { |
1062 | return true; |
1063 | } |
1064 | }; |
1065 | // </editor-fold> |
1066 | |
1067 | // <editor-fold defaultstate="collapsed" desc="disjointTypes"> |
1068 | public boolean disjointTypes(List<Type> ts, List<Type> ss) { |
1069 | while (ts.tail != null && ss.tail != null) { |
1070 | if (disjointType(ts.head, ss.head)) return true; |
1071 | ts = ts.tail; |
1072 | ss = ss.tail; |
1073 | } |
1074 | return false; |
1075 | } |
1076 | |
1077 | /** |
1078 | * Two types or wildcards are considered disjoint if it can be |
1079 | * proven that no type can be contained in both. It is |
1080 | * conservative in that it is allowed to say that two types are |
1081 | * not disjoint, even though they actually are. |
1082 | * |
1083 | * The type C<X> is castable to C<Y> exactly if X and Y are not |
1084 | * disjoint. |
1085 | */ |
1086 | public boolean disjointType(Type t, Type s) { |
1087 | return disjointType.visit(t, s); |
1088 | } |
1089 | // where |
1090 | private TypeRelation disjointType = new TypeRelation() { |
1091 | |
1092 | private Set<TypePair> cache = new HashSet<TypePair>(); |
1093 | |
1094 | public Boolean visitType(Type t, Type s) { |
1095 | if (s.tag == WILDCARD) |
1096 | return visit(s, t); |
1097 | else |
1098 | return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t); |
1099 | } |
1100 | |
1101 | private boolean isCastableRecursive(Type t, Type s) { |
1102 | TypePair pair = new TypePair(t, s); |
1103 | if (cache.add(pair)) { |
1104 | try { |
1105 | return Types.this.isCastable(t, s); |
1106 | } finally { |
1107 | cache.remove(pair); |
1108 | } |
1109 | } else { |
1110 | return true; |
1111 | } |
1112 | } |
1113 | |
1114 | private boolean notSoftSubtypeRecursive(Type t, Type s) { |
1115 | TypePair pair = new TypePair(t, s); |
1116 | if (cache.add(pair)) { |
1117 | try { |
1118 | return Types.this.notSoftSubtype(t, s); |
1119 | } finally { |
1120 | cache.remove(pair); |
1121 | } |
1122 | } else { |
1123 | return false; |
1124 | } |
1125 | } |
1126 | |
1127 | @Override |
1128 | public Boolean visitWildcardType(WildcardType t, Type s) { |
1129 | if (t.isUnbound()) |
1130 | return false; |
1131 | |
1132 | if (s.tag != WILDCARD) { |
1133 | if (t.isExtendsBound()) |
1134 | return notSoftSubtypeRecursive(s, t.type); |
1135 | else // isSuperBound() |
1136 | return notSoftSubtypeRecursive(t.type, s); |
1137 | } |
1138 | |
1139 | if (s.isUnbound()) |
1140 | return false; |
1141 | |
1142 | if (t.isExtendsBound()) { |
1143 | if (s.isExtendsBound()) |
1144 | return !isCastableRecursive(t.type, upperBound(s)); |
1145 | else if (s.isSuperBound()) |
1146 | return notSoftSubtypeRecursive(lowerBound(s), t.type); |
1147 | } else if (t.isSuperBound()) { |
1148 | if (s.isExtendsBound()) |
1149 | return notSoftSubtypeRecursive(t.type, upperBound(s)); |
1150 | } |
1151 | return false; |
1152 | } |
1153 | }; |
1154 | // </editor-fold> |
1155 | |
1156 | // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes"> |
1157 | /** |
1158 | * Returns the lower bounds of the formals of a method. |
1159 | */ |
1160 | public List<Type> lowerBoundArgtypes(Type t) { |
1161 | return map(t.getParameterTypes(), lowerBoundMapping); |
1162 | } |
1163 | private final Mapping lowerBoundMapping = new Mapping("lowerBound") { |
1164 | public Type apply(Type t) { |
1165 | return lowerBound(t); |
1166 | } |
1167 | }; |
1168 | // </editor-fold> |
1169 | |
1170 | // <editor-fold defaultstate="collapsed" desc="notSoftSubtype"> |
1171 | /** |
1172 | * This relation answers the question: is impossible that |
1173 | * something of type `t' can be a subtype of `s'? This is |
1174 | * different from the question "is `t' not a subtype of `s'?" |
1175 | * when type variables are involved: Integer is not a subtype of T |
1176 | * where <T extends Number> but it is not true that Integer cannot |
1177 | * possibly be a subtype of T. |
1178 | */ |
1179 | public boolean notSoftSubtype(Type t, Type s) { |
1180 | if (t == s) return false; |
1181 | if (t.tag == TYPEVAR) { |
1182 | TypeVar tv = (TypeVar) t; |
1183 | if (s.tag == TYPEVAR) |
1184 | s = s.getUpperBound(); |
1185 | return !isCastable(tv.bound, |
1186 | s, |
1187 | Warner.noWarnings); |
1188 | } |
1189 | if (s.tag != WILDCARD) |
1190 | s = upperBound(s); |
1191 | if (s.tag == TYPEVAR) |
1192 | s = s.getUpperBound(); |
1193 | return !isSubtype(t, s); |
1194 | } |
1195 | // </editor-fold> |
1196 | |
1197 | // <editor-fold defaultstate="collapsed" desc="isReifiable"> |
1198 | public boolean isReifiable(Type t) { |
1199 | return isReifiable.visit(t); |
1200 | } |
1201 | // where |
1202 | private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() { |
1203 | |
1204 | public Boolean visitType(Type t, Void ignored) { |
1205 | return true; |
1206 | } |
1207 | |
1208 | @Override |
1209 | public Boolean visitClassType(ClassType t, Void ignored) { |
1210 | if (!t.isParameterized()) |
1211 | return true; |
1212 | |
1213 | for (Type param : t.allparams()) { |
1214 | if (!param.isUnbound()) |
1215 | return false; |
1216 | } |
1217 | return true; |
1218 | } |
1219 | |
1220 | @Override |
1221 | public Boolean visitArrayType(ArrayType t, Void ignored) { |
1222 | return visit(t.elemtype); |
1223 | } |
1224 | |
1225 | @Override |
1226 | public Boolean visitTypeVar(TypeVar t, Void ignored) { |
1227 | return false; |
1228 | } |
1229 | }; |
1230 | // </editor-fold> |
1231 | |
1232 | // <editor-fold defaultstate="collapsed" desc="Array Utils"> |
1233 | public boolean isArray(Type t) { |
1234 | while (t.tag == WILDCARD) |
1235 | t = upperBound(t); |
1236 | return t.tag == ARRAY; |
1237 | } |
1238 | |
1239 | /** |
1240 | * The element type of an array. |
1241 | */ |
1242 | public Type elemtype(Type t) { |
1243 | switch (t.tag) { |
1244 | case WILDCARD: |
1245 | return elemtype(upperBound(t)); |
1246 | case ARRAY: |
1247 | return ((ArrayType)t).elemtype; |
1248 | case FORALL: |
1249 | return elemtype(((ForAll)t).qtype); |
1250 | case ERROR: |
1251 | return t; |
1252 | default: |
1253 | return null; |
1254 | } |
1255 | } |
1256 | |
1257 | /** |
1258 | * Mapping to take element type of an arraytype |
1259 | */ |
1260 | private Mapping elemTypeFun = new Mapping ("elemTypeFun") { |
1261 | public Type apply(Type t) { return elemtype(t); } |
1262 | }; |
1263 | |
1264 | /** |
1265 | * The number of dimensions of an array type. |
1266 | */ |
1267 | public int dimensions(Type t) { |
1268 | int result = 0; |
1269 | while (t.tag == ARRAY) { |
1270 | result++; |
1271 | t = elemtype(t); |
1272 | } |
1273 | return result; |
1274 | } |
1275 | // </editor-fold> |
1276 | |
1277 | // <editor-fold defaultstate="collapsed" desc="asSuper"> |
1278 | /** |
1279 | * Return the (most specific) base type of t that starts with the |
1280 | * given symbol. If none exists, return null. |
1281 | * |
1282 | * @param t a type |
1283 | * @param sym a symbol |
1284 | */ |
1285 | public Type asSuper(Type t, Symbol sym) { |
1286 | return asSuper.visit(t, sym); |
1287 | } |
1288 | // where |
1289 | private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() { |
1290 | |
1291 | public Type visitType(Type t, Symbol sym) { |
1292 | return null; |
1293 | } |
1294 | |
1295 | @Override |
1296 | public Type visitClassType(ClassType t, Symbol sym) { |
1297 | if (t.tsym == sym) |
1298 | return t; |
1299 | |
1300 | Type st = supertype(t); |
1301 | if (st.tag == CLASS || st.tag == ERROR) { |
1302 | Type x = asSuper(st, sym); |
1303 | if (x != null) |
1304 | return x; |
1305 | } |
1306 | if ((sym.flags() & INTERFACE) != 0) { |
1307 | for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { |
1308 | Type x = asSuper(l.head, sym); |
1309 | if (x != null) |
1310 | return x; |
1311 | } |
1312 | } |
1313 | return null; |
1314 | } |
1315 | |
1316 | @Override |
1317 | public Type visitArrayType(ArrayType t, Symbol sym) { |
1318 | return isSubtype(t, sym.type) ? sym.type : null; |
1319 | } |
1320 | |
1321 | @Override |
1322 | public Type visitTypeVar(TypeVar t, Symbol sym) { |
1323 | return asSuper(t.bound, sym); |
1324 | } |
1325 | |
1326 | @Override |
1327 | public Type visitErrorType(ErrorType t, Symbol sym) { |
1328 | return t; |
1329 | } |
1330 | }; |
1331 | |
1332 | /** |
1333 | * Return the base type of t or any of its outer types that starts |
1334 | * with the given symbol. If none exists, return null. |
1335 | * |
1336 | * @param t a type |
1337 | * @param sym a symbol |
1338 | */ |
1339 | public Type asOuterSuper(Type t, Symbol sym) { |
1340 | switch (t.tag) { |
1341 | case CLASS: |
1342 | do { |
1343 | Type s = asSuper(t, sym); |
1344 | if (s != null) return s; |
1345 | t = t.getEnclosingType(); |
1346 | } while (t.tag == CLASS); |
1347 | return null; |
1348 | case ARRAY: |
1349 | return isSubtype(t, sym.type) ? sym.type : null; |
1350 | case TYPEVAR: |
1351 | return asSuper(t, sym); |
1352 | case ERROR: |
1353 | return t; |
1354 | default: |
1355 | return null; |
1356 | } |
1357 | } |
1358 | |
1359 | /** |
1360 | * Return the base type of t or any of its enclosing types that |
1361 | * starts with the given symbol. If none exists, return null. |
1362 | * |
1363 | * @param t a type |
1364 | * @param sym a symbol |
1365 | */ |
1366 | public Type asEnclosingSuper(Type t, Symbol sym) { |
1367 | switch (t.tag) { |
1368 | case CLASS: |
1369 | do { |
1370 | Type s = asSuper(t, sym); |
1371 | if (s != null) return s; |
1372 | Type outer = t.getEnclosingType(); |
1373 | t = (outer.tag == CLASS) ? outer : |
1374 | (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type : |
1375 | Type.noType; |
1376 | } while (t.tag == CLASS); |
1377 | return null; |
1378 | case ARRAY: |
1379 | return isSubtype(t, sym.type) ? sym.type : null; |
1380 | case TYPEVAR: |
1381 | return asSuper(t, sym); |
1382 | case ERROR: |
1383 | return t; |
1384 | default: |
1385 | return null; |
1386 | } |
1387 | } |
1388 | // </editor-fold> |
1389 | |
1390 | // <editor-fold defaultstate="collapsed" desc="memberType"> |
1391 | /** |
1392 | * The type of given symbol, seen as a member of t. |
1393 | * |
1394 | * @param t a type |
1395 | * @param sym a symbol |
1396 | */ |
1397 | public Type memberType(Type t, Symbol sym) { |
1398 | return (sym.flags() & STATIC) != 0 |
1399 | ? sym.type |
1400 | : memberType.visit(t, sym); |
1401 | } |
1402 | // where |
1403 | private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() { |
1404 | |
1405 | public Type visitType(Type t, Symbol sym) { |
1406 | return sym.type; |
1407 | } |
1408 | |
1409 | @Override |
1410 | public Type visitWildcardType(WildcardType t, Symbol sym) { |
1411 | return memberType(upperBound(t), sym); |
1412 | } |
1413 | |
1414 | @Override |
1415 | public Type visitClassType(ClassType t, Symbol sym) { |
1416 | Symbol owner = sym.owner; |
1417 | long flags = sym.flags(); |
1418 | if (((flags & STATIC) == 0) && owner.type.isParameterized()) { |
1419 | Type base = asOuterSuper(t, owner); |
1420 | if (base != null) { |
1421 | List<Type> ownerParams = owner.type.allparams(); |
1422 | List<Type> baseParams = base.allparams(); |
1423 | if (ownerParams.nonEmpty()) { |
1424 | if (baseParams.isEmpty()) { |
1425 | // then base is a raw type |
1426 | return erasure(sym.type); |
1427 | } else { |
1428 | return subst(sym.type, ownerParams, baseParams); |
1429 | } |
1430 | } |
1431 | } |
1432 | } |
1433 | return sym.type; |
1434 | } |
1435 | |
1436 | @Override |
1437 | public Type visitTypeVar(TypeVar t, Symbol sym) { |
1438 | return memberType(t.bound, sym); |
1439 | } |
1440 | |
1441 | @Override |
1442 | public Type visitErrorType(ErrorType t, Symbol sym) { |
1443 | return t; |
1444 | } |
1445 | }; |
1446 | // </editor-fold> |
1447 | |
1448 | // <editor-fold defaultstate="collapsed" desc="isAssignable"> |
1449 | public boolean isAssignable(Type t, Type s) { |
1450 | return isAssignable(t, s, Warner.noWarnings); |
1451 | } |
1452 | |
1453 | /** |
1454 | * Is t assignable to s?<br> |
1455 | * Equivalent to subtype except for constant values and raw |
1456 | * types.<br> |
1457 | * (not defined for Method and ForAll types) |
1458 | */ |
1459 | public boolean isAssignable(Type t, Type s, Warner warn) { |
1460 | if (t.tag == ERROR) |
1461 | return true; |
1462 | if (t.tag <= INT && t.constValue() != null) { |
1463 | int value = ((Number)t.constValue()).intValue(); |
1464 | switch (s.tag) { |
1465 | case BYTE: |
1466 | if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE) |
1467 | return true; |
1468 | break; |
1469 | case CHAR: |
1470 | if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE) |
1471 | return true; |
1472 | break; |
1473 | case SHORT: |
1474 | if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE) |
1475 | return true; |
1476 | break; |
1477 | case INT: |
1478 | return true; |
1479 | case CLASS: |
1480 | switch (unboxedType(s).tag) { |
1481 | case BYTE: |
1482 | case CHAR: |
1483 | case SHORT: |
1484 | return isAssignable(t, unboxedType(s), warn); |
1485 | } |
1486 | break; |
1487 | } |
1488 | } |
1489 | return isConvertible(t, s, warn); |
1490 | } |
1491 | // </editor-fold> |
1492 | |
1493 | // <editor-fold defaultstate="collapsed" desc="erasure"> |
1494 | /** |
1495 | * The erasure of t {@code |t|} -- the type that results when all |
1496 | * type parameters in t are deleted. |
1497 | */ |
1498 | public Type erasure(Type t) { |
1499 | if (t.tag <= lastBaseTag) |
1500 | return t; /* fast special case */ |
1501 | else |
1502 | return erasure.visit(t); |
1503 | } |
1504 | // where |
1505 | private UnaryVisitor<Type> erasure = new UnaryVisitor<Type>() { |
1506 | public Type visitType(Type t, Void ignored) { |
1507 | if (t.tag <= lastBaseTag) |
1508 | return t; /*fast special case*/ |
1509 | else |
1510 | return t.map(erasureFun); |
1511 | } |
1512 | |
1513 | @Override |
1514 | public Type visitWildcardType(WildcardType t, Void ignored) { |
1515 | return erasure(upperBound(t)); |
1516 | } |
1517 | |
1518 | @Override |
1519 | public Type visitClassType(ClassType t, Void ignored) { |
1520 | return t.tsym.erasure(Types.this); |
1521 | } |
1522 | |
1523 | @Override |
1524 | public Type visitTypeVar(TypeVar t, Void ignored) { |
1525 | return erasure(t.bound); |
1526 | } |
1527 | |
1528 | @Override |
1529 | public Type visitErrorType(ErrorType t, Void ignored) { |
1530 | return t; |
1531 | } |
1532 | }; |
1533 | private Mapping erasureFun = new Mapping ("erasure") { |
1534 | public Type apply(Type t) { return erasure(t); } |
1535 | }; |
1536 | |
1537 | public List<Type> erasure(List<Type> ts) { |
1538 | return Type.map(ts, erasureFun); |
1539 | } |
1540 | // </editor-fold> |
1541 | |
1542 | // <editor-fold defaultstate="collapsed" desc="makeCompoundType"> |
1543 | /** |
1544 | * Make a compound type from non-empty list of types |
1545 | * |
1546 | * @param bounds the types from which the compound type is formed |
1547 | * @param supertype is objectType if all bounds are interfaces, |
1548 | * null otherwise. |
1549 | */ |
1550 | public Type makeCompoundType(List<Type> bounds, |
1551 | Type supertype) { |
1552 | ClassSymbol bc = |
1553 | new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC, |
1554 | Type.moreInfo |
1555 | ? names.fromString(bounds.toString()) |
1556 | : names.empty, |
1557 | syms.noSymbol); |
1558 | if (bounds.head.tag == TYPEVAR) |
1559 | // error condition, recover |
1560 | bc.erasure_field = syms.objectType; |
1561 | else |
1562 | bc.erasure_field = erasure(bounds.head); |
1563 | bc.members_field = new Scope(bc); |
1564 | ClassType bt = (ClassType)bc.type; |
1565 | bt.allparams_field = List.nil(); |
1566 | if (supertype != null) { |
1567 | bt.supertype_field = supertype; |
1568 | bt.interfaces_field = bounds; |
1569 | } else { |
1570 | bt.supertype_field = bounds.head; |
1571 | bt.interfaces_field = bounds.tail; |
1572 | } |
1573 | assert bt.supertype_field.tsym.completer != null |
1574 | || !bt.supertype_field.isInterface() |
1575 | : bt.supertype_field; |
1576 | return bt; |
1577 | } |
1578 | |
1579 | /** |
1580 | * Same as {@link #makeCompoundType(List,Type)}, except that the |
1581 | * second parameter is computed directly. Note that this might |
1582 | * cause a symbol completion. Hence, this version of |
1583 | * makeCompoundType may not be called during a classfile read. |
1584 | */ |
1585 | public Type makeCompoundType(List<Type> bounds) { |
1586 | Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ? |
1587 | supertype(bounds.head) : null; |
1588 | return makeCompoundType(bounds, supertype); |
1589 | } |
1590 | |
1591 | /** |
1592 | * A convenience wrapper for {@link #makeCompoundType(List)}; the |
1593 | * arguments are converted to a list and passed to the other |
1594 | * method. Note that this might cause a symbol completion. |
1595 | * Hence, this version of makeCompoundType may not be called |
1596 | * during a classfile read. |
1597 | */ |
1598 | public Type makeCompoundType(Type bound1, Type bound2) { |
1599 | return makeCompoundType(List.of(bound1, bound2)); |
1600 | } |
1601 | // </editor-fold> |
1602 | |
1603 | // <editor-fold defaultstate="collapsed" desc="supertype"> |
1604 | public Type supertype(Type t) { |
1605 | return supertype.visit(t); |
1606 | } |
1607 | // where |
1608 | private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() { |
1609 | |
1610 | public Type visitType(Type t, Void ignored) { |
1611 | // A note on wildcards: there is no good way to |
1612 | // determine a supertype for a super bounded wildcard. |
1613 | return null; |
1614 | } |
1615 | |
1616 | @Override |
1617 | public Type visitClassType(ClassType t, Void ignored) { |
1618 | if (t.supertype_field == null) { |
1619 | Type supertype = ((ClassSymbol)t.tsym).getSuperclass(); |
1620 | // An interface has no superclass; its supertype is Object. |
1621 | if (t.isInterface()) |
1622 | supertype = ((ClassType)t.tsym.type).supertype_field; |
1623 | if (t.supertype_field == null) { |
1624 | List<Type> actuals = classBound(t).allparams(); |
1625 | List<Type> formals = t.tsym.type.allparams(); |
1626 | if (actuals.isEmpty()) { |
1627 | if (formals.isEmpty()) |
1628 | // Should not happen. See comments below in interfaces |
1629 | t.supertype_field = supertype; |
1630 | else |
1631 | t.supertype_field = erasure(supertype); |
1632 | } else { |
1633 | t.supertype_field = subst(supertype, formals, actuals); |
1634 | } |
1635 | } |
1636 | } |
1637 | return t.supertype_field; |
1638 | } |
1639 | |
1640 | /** |
1641 | * The supertype is always a class type. If the type |
1642 | * variable's bounds start with a class type, this is also |
1643 | * the supertype. Otherwise, the supertype is |
1644 | * java.lang.Object. |
1645 | */ |
1646 | @Override |
1647 | public Type visitTypeVar(TypeVar t, Void ignored) { |
1648 | if (t.bound.tag == TYPEVAR || |
1649 | (!t.bound.isCompound() && !t.bound.isInterface())) { |
1650 | return t.bound; |
1651 | } else { |
1652 | return supertype(t.bound); |
1653 | } |
1654 | } |
1655 | |
1656 | @Override |
1657 | public Type visitArrayType(ArrayType t, Void ignored) { |
1658 | if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType)) |
1659 | return arraySuperType(); |
1660 | else |
1661 | return new ArrayType(supertype(t.elemtype), t.tsym); |
1662 | } |
1663 | |
1664 | @Override |
1665 | public Type visitErrorType(ErrorType t, Void ignored) { |
1666 | return t; |
1667 | } |
1668 | }; |
1669 | // </editor-fold> |
1670 | |
1671 | // <editor-fold defaultstate="collapsed" desc="interfaces"> |
1672 | /** |
1673 | * Return the interfaces implemented by this class. |
1674 | */ |
1675 | public List<Type> interfaces(Type t) { |
1676 | return interfaces.visit(t); |
1677 | } |
1678 | // where |
1679 | private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() { |
1680 | |
1681 | public List<Type> visitType(Type t, Void ignored) { |
1682 | return List.nil(); |
1683 | } |
1684 | |
1685 | @Override |
1686 | public List<Type> visitClassType(ClassType t, Void ignored) { |
1687 | if (t.interfaces_field == null) { |
1688 | List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces(); |
1689 | if (t.interfaces_field == null) { |
1690 | // If t.interfaces_field is null, then t must |
1691 | // be a parameterized type (not to be confused |
1692 | // with a generic type declaration). |
1693 | // Terminology: |
1694 | // Parameterized type: List<String> |
1695 | // Generic type declaration: class List<E> { ... } |
1696 | // So t corresponds to List<String> and |
1697 | // t.tsym.type corresponds to List<E>. |
1698 | // The reason t must be parameterized type is |
1699 | // that completion will happen as a side |
1700 | // effect of calling |
1701 | // ClassSymbol.getInterfaces. Since |
1702 | // t.interfaces_field is null after |
1703 | // completion, we can assume that t is not the |
1704 | // type of a class/interface declaration. |
1705 | assert t != t.tsym.type : t.toString(); |
1706 | List<Type> actuals = t.allparams(); |
1707 | List<Type> formals = t.tsym.type.allparams(); |
1708 | if (actuals.isEmpty()) { |
1709 | if (formals.isEmpty()) { |
1710 | // In this case t is not generic (nor raw). |
1711 | // So this should not happen. |
1712 | t.interfaces_field = interfaces; |
1713 | } else { |
1714 | t.interfaces_field = erasure(interfaces); |
1715 | } |
1716 | } else { |
1717 | t.interfaces_field = |
1718 | upperBounds(subst(interfaces, formals, actuals)); |
1719 | } |
1720 | } |
1721 | } |
1722 | return t.interfaces_field; |
1723 | } |
1724 | |
1725 | @Override |
1726 | public List<Type> visitTypeVar(TypeVar t, Void ignored) { |
1727 | if (t.bound.isCompound()) |
1728 | return interfaces(t.bound); |
1729 | |
1730 | if (t.bound.isInterface()) |
1731 | return List.of(t.bound); |
1732 | |
1733 | return List.nil(); |
1734 | } |
1735 | }; |
1736 | // </editor-fold> |
1737 | |
1738 | // <editor-fold defaultstate="collapsed" desc="isDerivedRaw"> |
1739 | Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>(); |
1740 | |
1741 | public boolean isDerivedRaw(Type t) { |
1742 | Boolean result = isDerivedRawCache.get(t); |
1743 | if (result == null) { |
1744 | result = isDerivedRawInternal(t); |
1745 | isDerivedRawCache.put(t, result); |
1746 | } |
1747 | return result; |
1748 | } |
1749 | |
1750 | public boolean isDerivedRawInternal(Type t) { |
1751 | if (t.isErroneous()) |
1752 | return false; |
1753 | return |
1754 | t.isRaw() || |
1755 | supertype(t) != null && isDerivedRaw(supertype(t)) || |
1756 | isDerivedRaw(interfaces(t)); |
1757 | } |
1758 | |
1759 | public boolean isDerivedRaw(List<Type> ts) { |
1760 | List<Type> l = ts; |
1761 | while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail; |
1762 | return l.nonEmpty(); |
1763 | } |
1764 | // </editor-fold> |
1765 | |
1766 | // <editor-fold defaultstate="collapsed" desc="setBounds"> |
1767 | /** |
1768 | * Set the bounds field of the given type variable to reflect a |
1769 | * (possibly multiple) list of bounds. |
1770 | * @param t a type variable |
1771 | * @param bounds the bounds, must be nonempty |
1772 | * @param supertype is objectType if all bounds are interfaces, |
1773 | * null otherwise. |
1774 | */ |
1775 | public void setBounds(TypeVar t, List<Type> bounds, Type supertype) { |
1776 | if (bounds.tail.isEmpty()) |
1777 | t.bound = bounds.head; |
1778 | else |
1779 | t.bound = makeCompoundType(bounds, supertype); |
1780 | t.rank_field = -1; |
1781 | } |
1782 | |
1783 | /** |
1784 | * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that |
1785 | * third parameter is computed directly. Note that this test |
1786 | * might cause a symbol completion. Hence, this version of |
1787 | * setBounds may not be called during a classfile read. |
1788 | */ |
1789 | public void setBounds(TypeVar t, List<Type> bounds) { |
1790 | Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ? |
1791 | supertype(bounds.head) : null; |
1792 | setBounds(t, bounds, supertype); |
1793 | t.rank_field = -1; |
1794 | } |
1795 | // </editor-fold> |
1796 | |
1797 | // <editor-fold defaultstate="collapsed" desc="getBounds"> |
1798 | /** |
1799 | * Return list of bounds of the given type variable. |
1800 | */ |
1801 | public List<Type> getBounds(TypeVar t) { |
1802 | if (t.bound.isErroneous() || !t.bound.isCompound()) |
1803 | return List.of(t.bound); |
1804 | else if ((erasure(t).tsym.flags() & INTERFACE) == 0) |
1805 | return interfaces(t).prepend(supertype(t)); |
1806 | else |
1807 | // No superclass was given in bounds. |
1808 | // In this case, supertype is Object, erasure is first interface. |
1809 | return interfaces(t); |
1810 | } |
1811 | // </editor-fold> |
1812 | |
1813 | // <editor-fold defaultstate="collapsed" desc="classBound"> |
1814 | /** |
1815 | * If the given type is a (possibly selected) type variable, |
1816 | * return the bounding class of this type, otherwise return the |
1817 | * type itself. |
1818 | */ |
1819 | public Type classBound(Type t) { |
1820 | return classBound.visit(t); |
1821 | } |
1822 | // where |
1823 | private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() { |
1824 | |
1825 | public Type visitType(Type t, Void ignored) { |
1826 | return t; |
1827 | } |
1828 | |
1829 | @Override |
1830 | public Type visitClassType(ClassType t, Void ignored) { |
1831 | Type outer1 = classBound(t.getEnclosingType()); |
1832 | if (outer1 != t.getEnclosingType()) |
1833 | return new ClassType(outer1, t.getTypeArguments(), t.tsym); |
1834 | else |
1835 | return t; |
1836 | } |
1837 | |
1838 | @Override |
1839 | public Type visitTypeVar(TypeVar t, Void ignored) { |
1840 | return classBound(supertype(t)); |
1841 | } |
1842 | |
1843 | @Override |
1844 | public Type visitErrorType(ErrorType t, Void ignored) { |
1845 | return t; |
1846 | } |
1847 | }; |
1848 | // </editor-fold> |
1849 | |
1850 | // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence"> |
1851 | /** |
1852 | * Returns true iff the first signature is a <em>sub |
1853 | * signature</em> of the other. This is <b>not</b> an equivalence |
1854 | * relation. |
1855 | * |
1856 | * @see "The Java Language Specification, Third Ed. (8.4.2)." |
1857 | * @see #overrideEquivalent(Type t, Type s) |
1858 | * @param t first signature (possibly raw). |
1859 | * @param s second signature (could be subjected to erasure). |
1860 | * @return true if t is a sub signature of s. |
1861 | */ |
1862 | public boolean isSubSignature(Type t, Type s) { |
1863 | return hasSameArgs(t, s) || hasSameArgs(t, erasure(s)); |
1864 | } |
1865 | |
1866 | /** |
1867 | * Returns true iff these signatures are related by <em>override |
1868 | * equivalence</em>. This is the natural extension of |
1869 | * isSubSignature to an equivalence relation. |
1870 | * |
1871 | * @see "The Java Language Specification, Third Ed. (8.4.2)." |
1872 | * @see #isSubSignature(Type t, Type s) |
1873 | * @param t a signature (possible raw, could be subjected to |
1874 | * erasure). |
1875 | * @param s a signature (possible raw, could be subjected to |
1876 | * erasure). |
1877 | * @return true if either argument is a sub signature of the other. |
1878 | */ |
1879 | public boolean overrideEquivalent(Type t, Type s) { |
1880 | return hasSameArgs(t, s) || |
1881 | hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s); |
1882 | } |
1883 | |
1884 | /** |
1885 | * Does t have the same arguments as s? It is assumed that both |
1886 | * types are (possibly polymorphic) method types. Monomorphic |
1887 | * method types "have the same arguments", if their argument lists |
1888 | * are equal. Polymorphic method types "have the same arguments", |
1889 | * if they have the same arguments after renaming all type |
1890 | * variables of one to corresponding type variables in the other, |
1891 | * where correspondence is by position in the type parameter list. |
1892 | */ |
1893 | public boolean hasSameArgs(Type t, Type s) { |
1894 | return hasSameArgs.visit(t, s); |
1895 | } |
1896 | // where |
1897 | private TypeRelation hasSameArgs = new TypeRelation() { |
1898 | |
1899 | public Boolean visitType(Type t, Type s) { |
1900 | throw new AssertionError(); |
1901 | } |
1902 | |
1903 | @Override |
1904 | public Boolean visitMethodType(MethodType t, Type s) { |
1905 | return s.tag == METHOD |
1906 | && containsTypeEquivalent(t.argtypes, s.getParameterTypes()); |
1907 | } |
1908 | |
1909 | @Override |
1910 | public Boolean visitForAll(ForAll t, Type s) { |
1911 | if (s.tag != FORALL) |
1912 | return false; |
1913 | |
1914 | ForAll forAll = (ForAll)s; |
1915 | return hasSameBounds(t, forAll) |
1916 | && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); |
1917 | } |
1918 | |
1919 | @Override |
1920 | public Boolean visitErrorType(ErrorType t, Type s) { |
1921 | return false; |
1922 | } |
1923 | }; |
1924 | // </editor-fold> |
1925 | |
1926 | // <editor-fold defaultstate="collapsed" desc="subst"> |
1927 | public List<Type> subst(List<Type> ts, |
1928 | List<Type> from, |
1929 | List<Type> to) { |
1930 | return new Subst(from, to).subst(ts); |
1931 | } |
1932 | |
1933 | /** |
1934 | * Substitute all occurrences of a type in `from' with the |
1935 | * corresponding type in `to' in 't'. Match lists `from' and `to' |
1936 | * from the right: If lists have different length, discard leading |
1937 | * elements of the longer list. |
1938 | */ |
1939 | public Type subst(Type t, List<Type> from, List<Type> to) { |
1940 | return new Subst(from, to).subst(t); |
1941 | } |
1942 | |
1943 | private class Subst extends UnaryVisitor<Type> { |
1944 | List<Type> from; |
1945 | List<Type> to; |
1946 | |
1947 | public Subst(List<Type> from, List<Type> to) { |
1948 | int fromLength = from.length(); |
1949 | int toLength = to.length(); |
1950 | while (fromLength > toLength) { |
1951 | fromLength--; |
1952 | from = from.tail; |
1953 | } |
1954 | while (fromLength < toLength) { |
1955 | toLength--; |
1956 | to = to.tail; |
1957 | } |
1958 | this.from = from; |
1959 | this.to = to; |
1960 | } |
1961 | |
1962 | Type subst(Type t) { |
1963 | if (from.tail == null) |
1964 | return t; |
1965 | else |
1966 | return visit(t); |
1967 | } |
1968 | |
1969 | List<Type> subst(List<Type> ts) { |
1970 | if (from.tail == null) |
1971 | return ts; |
1972 | boolean wild = false; |
1973 | if (ts.nonEmpty() && from.nonEmpty()) { |
1974 | Type head1 = subst(ts.head); |
1975 | List<Type> tail1 = subst(ts.tail); |
1976 | if (head1 != ts.head || tail1 != ts.tail) |
1977 | return tail1.prepend(head1); |
1978 | } |
1979 | return ts; |
1980 | } |
1981 | |
1982 | public Type visitType(Type t, Void ignored) { |
1983 | return t; |
1984 | } |
1985 | |
1986 | @Override |
1987 | public Type visitMethodType(MethodType t, Void ignored) { |
1988 | List<Type> argtypes = subst(t.argtypes); |
1989 | Type restype = subst(t.restype); |
1990 | List<Type> thrown = subst(t.thrown); |
1991 | if (argtypes == t.argtypes && |
1992 | restype == t.restype && |
1993 | thrown == t.thrown) |
1994 | return t; |
1995 | else |
1996 | return new MethodType(argtypes, restype, thrown, t.tsym); |
1997 | } |
1998 | |
1999 | @Override |
2000 | public Type visitTypeVar(TypeVar t, Void ignored) { |
2001 | for (List<Type> from = this.from, to = this.to; |
2002 | from.nonEmpty(); |
2003 | from = from.tail, to = to.tail) { |
2004 | if (t == from.head) { |
2005 | return to.head.withTypeVar(t); |
2006 | } |
2007 | } |
2008 | return t; |
2009 | } |
2010 | |
2011 | @Override |
2012 | public Type visitClassType(ClassType t, Void ignored) { |
2013 | if (!t.isCompound()) { |
2014 | List<Type> typarams = t.getTypeArguments(); |
2015 | List<Type> typarams1 = subst(typarams); |
2016 | Type outer = t.getEnclosingType(); |
2017 | Type outer1 = subst(outer); |
2018 | if (typarams1 == typarams && outer1 == outer) |
2019 | return t; |
2020 | else |
2021 | return new ClassType(outer1, typarams1, t.tsym); |
2022 | } else { |
2023 | Type st = subst(supertype(t)); |
2024 | List<Type> is = upperBounds(subst(interfaces(t))); |
2025 | if (st == supertype(t) && is == interfaces(t)) |
2026 | return t; |
2027 | else |
2028 | return makeCompoundType(is.prepend(st)); |
2029 | } |
2030 | } |
2031 | |
2032 | @Override |
2033 | public Type visitWildcardType(WildcardType t, Void ignored) { |
2034 | Type bound = t.type; |
2035 | if (t.kind != BoundKind.UNBOUND) |
2036 | bound = subst(bound); |
2037 | if (bound == t.type) { |
2038 | return t; |
2039 | } else { |
2040 | if (t.isExtendsBound() && bound.isExtendsBound()) |
2041 | bound = upperBound(bound); |
2042 | return new WildcardType(bound, t.kind, syms.boundClass, t.bound); |
2043 | } |
2044 | } |
2045 | |
2046 | @Override |
2047 | public Type visitArrayType(ArrayType t, Void ignored) { |
2048 | Type elemtype = subst(t.elemtype); |
2049 | if (elemtype == t.elemtype) |
2050 | return t; |
2051 | else |
2052 | return new ArrayType(upperBound(elemtype), t.tsym); |
2053 | } |
2054 | |
2055 | @Override |
2056 | public Type visitForAll(ForAll t, Void ignored) { |
2057 | List<Type> tvars1 = substBounds(t.tvars, from, to); |
2058 | Type qtype1 = subst(t.qtype); |
2059 | if (tvars1 == t.tvars && qtype1 == t.qtype) { |
2060 | return t; |
2061 | } else if (tvars1 == t.tvars) { |
2062 | return new ForAll(tvars1, qtype1); |
2063 | } else { |
2064 | return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)); |
2065 | } |
2066 | } |
2067 | |
2068 | @Override |
2069 | public Type visitErrorType(ErrorType t, Void ignored) { |
2070 | return t; |
2071 | } |
2072 | } |
2073 | |
2074 | public List<Type> substBounds(List<Type> tvars, |
2075 | List<Type> from, |
2076 | List<Type> to) { |
2077 | if (tvars.isEmpty()) |
2078 | return tvars; |
2079 | if (tvars.tail.isEmpty()) |
2080 | // fast common case |
2081 | return List.<Type>of(substBound((TypeVar)tvars.head, from, to)); |
2082 | ListBuffer<Type> newBoundsBuf = lb(); |
2083 | boolean changed = false; |
2084 | // calculate new bounds |
2085 | for (Type t : tvars) { |
2086 | TypeVar tv = (TypeVar) t; |
2087 | Type bound = subst(tv.bound, from, to); |
2088 | if (bound != tv.bound) |
2089 | changed = true; |
2090 | newBoundsBuf.append(bound); |
2091 | } |
2092 | if (!changed) |
2093 | return tvars; |
2094 | ListBuffer<Type> newTvars = lb(); |
2095 | // create new type variables without bounds |
2096 | for (Type t : tvars) { |
2097 | newTvars.append(new TypeVar(t.tsym, null, syms.botType)); |
2098 | } |
2099 | // the new bounds should use the new type variables in place |
2100 | // of the old |
2101 | List<Type> newBounds = newBoundsBuf.toList(); |
2102 | from = tvars; |
2103 | to = newTvars.toList(); |
2104 | for (; !newBounds.isEmpty(); newBounds = newBounds.tail) { |
2105 | newBounds.head = subst(newBounds.head, from, to); |
2106 | } |
2107 | newBounds = newBoundsBuf.toList(); |
2108 | // set the bounds of new type variables to the new bounds |
2109 | for (Type t : newTvars.toList()) { |
2110 | TypeVar tv = (TypeVar) t; |
2111 | tv.bound = newBounds.head; |
2112 | newBounds = newBounds.tail; |
2113 | } |
2114 | return newTvars.toList(); |
2115 | } |
2116 | |
2117 | public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) { |
2118 | Type bound1 = subst(t.bound, from, to); |
2119 | if (bound1 == t.bound) |
2120 | return t; |
2121 | else |
2122 | return new TypeVar(t.tsym, bound1, syms.botType); |
2123 | } |
2124 | // </editor-fold> |
2125 | |
2126 | // <editor-fold defaultstate="collapsed" desc="hasSameBounds"> |
2127 | /** |
2128 | * Does t have the same bounds for quantified variables as s? |
2129 | */ |
2130 | boolean hasSameBounds(ForAll t, ForAll s) { |
2131 | List<Type> l1 = t.tvars; |
2132 | List<Type> l2 = s.tvars; |
2133 | while (l1.nonEmpty() && l2.nonEmpty() && |
2134 | isSameType(l1.head.getUpperBound(), |
2135 | subst(l2.head.getUpperBound(), |
2136 | s.tvars, |
2137 | t.tvars))) { |
2138 | l1 = l1.tail; |
2139 | l2 = l2.tail; |
2140 | } |
2141 | return l1.isEmpty() && l2.isEmpty(); |
2142 | } |
2143 | // </editor-fold> |
2144 | |
2145 | // <editor-fold defaultstate="collapsed" desc="newInstances"> |
2146 | /** Create new vector of type variables from list of variables |
2147 | * changing all recursive bounds from old to new list. |
2148 | */ |
2149 | public List<Type> newInstances(List<Type> tvars) { |
2150 | List<Type> tvars1 = Type.map(tvars, newInstanceFun); |
2151 | for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) { |
2152 | TypeVar tv = (TypeVar) l.head; |
2153 | tv.bound = subst(tv.bound, tvars, tvars1); |
2154 | } |
2155 | return tvars1; |
2156 | } |
2157 | static private Mapping newInstanceFun = new Mapping("newInstanceFun") { |
2158 | public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); } |
2159 | }; |
2160 | // </editor-fold> |
2161 | |
2162 | // <editor-fold defaultstate="collapsed" desc="rank"> |
2163 | /** |
2164 | * The rank of a class is the length of the longest path between |
2165 | * the class and java.lang.Object in the class inheritance |
2166 | * graph. Undefined for all but reference types. |
2167 | */ |
2168 | public int rank(Type t) { |
2169 | switch(t.tag) { |
2170 | case CLASS: { |
2171 | ClassType cls = (ClassType)t; |
2172 | if (cls.rank_field < 0) { |
2173 | Name fullname = cls.tsym.getQualifiedName(); |
2174 | if (fullname == fullname.table.java_lang_Object) |
2175 | cls.rank_field = 0; |
2176 | else { |
2177 | int r = rank(supertype(cls)); |
2178 | for (List<Type> l = interfaces(cls); |
2179 | l.nonEmpty(); |
2180 | l = l.tail) { |
2181 | if (rank(l.head) > r) |
2182 | r = rank(l.head); |
2183 | } |
2184 | cls.rank_field = r + 1; |
2185 | } |
2186 | } |
2187 | return cls.rank_field; |
2188 | } |
2189 | case TYPEVAR: { |
2190 | TypeVar tvar = (TypeVar)t; |
2191 | if (tvar.rank_field < 0) { |
2192 | int r = rank(supertype(tvar)); |
2193 | for (List<Type> l = interfaces(tvar); |
2194 | l.nonEmpty(); |
2195 | l = l.tail) { |
2196 | if (rank(l.head) > r) r = rank(l.head); |
2197 | } |
2198 | tvar.rank_field = r + 1; |
2199 | } |
2200 | return tvar.rank_field; |
2201 | } |
2202 | case ERROR: |
2203 | return 0; |
2204 | default: |
2205 | throw new AssertionError(); |
2206 | } |
2207 | } |
2208 | // </editor-fold> |
2209 | |
2210 | // <editor-fold defaultstate="collapsed" desc="toString"> |
2211 | /** |
2212 | * This toString is slightly more descriptive than the one on Type. |
2213 | */ |
2214 | public String toString(Type t) { |
2215 | if (t.tag == FORALL) { |
2216 | ForAll forAll = (ForAll)t; |
2217 | return typaramsString(forAll.tvars) + forAll.qtype; |
2218 | } |
2219 | return "" + t; |
2220 | } |
2221 | // where |
2222 | private String typaramsString(List<Type> tvars) { |
2223 | StringBuffer s = new StringBuffer(); |
2224 | s.append('<'); |
2225 | boolean first = true; |
2226 | for (Type t : tvars) { |
2227 | if (!first) s.append(", "); |
2228 | first = false; |
2229 | appendTyparamString(((TypeVar)t), s); |
2230 | } |
2231 | s.append('>'); |
2232 | return s.toString(); |
2233 | } |
2234 | private void appendTyparamString(TypeVar t, StringBuffer buf) { |
2235 | buf.append(t); |
2236 | if (t.bound == null || |
2237 | t.bound.tsym.getQualifiedName() == names.java_lang_Object) |
2238 | return; |
2239 | buf.append(" extends "); // Java syntax; no need for i18n |
2240 | Type bound = t.bound; |
2241 | if (!bound.isCompound()) { |
2242 | buf.append(bound); |
2243 | } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) { |
2244 | buf.append(supertype(t)); |
2245 | for (Type intf : interfaces(t)) { |
2246 | buf.append('&'); |
2247 | buf.append(intf); |
2248 | } |
2249 | } else { |
2250 | // No superclass was given in bounds. |
2251 | // In this case, supertype is Object, erasure is first interface. |
2252 | boolean first = true; |
2253 | for (Type intf : interfaces(t)) { |
2254 | if (!first) buf.append('&'); |
2255 | first = false; |
2256 | buf.append(intf); |
2257 | } |
2258 | } |
2259 | } |
2260 | // </editor-fold> |
2261 | |
2262 | // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types"> |
2263 | /** |
2264 | * A cache for closures. |
2265 | * |
2266 | * <p>A closure is a list of all the supertypes and interfaces of |
2267 | * a class or interface type, ordered by ClassSymbol.precedes |
2268 | * (that is, subclasses come first, arbitrary but fixed |
2269 | * otherwise). |
2270 | */ |
2271 | private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>(); |
2272 | |
2273 | /** |
2274 | * Returns the closure of a class or interface type. |
2275 | */ |
2276 | public List<Type> closure(Type t) { |
2277 | List<Type> cl = closureCache.get(t); |
2278 | if (cl == null) { |
2279 | Type st = supertype(t); |
2280 | if (!t.isCompound()) { |
2281 | if (st.tag == CLASS) { |
2282 | cl = insert(closure(st), t); |
2283 | } else if (st.tag == TYPEVAR) { |
2284 | cl = closure(st).prepend(t); |
2285 | } else { |
2286 | cl = List.of(t); |
2287 | } |
2288 | } else { |
2289 | cl = closure(supertype(t)); |
2290 | } |
2291 | for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) |
2292 | cl = union(cl, closure(l.head)); |
2293 | closureCache.put(t, cl); |
2294 | } |
2295 | return cl; |
2296 | } |
2297 | |
2298 | /** |
2299 | * Insert a type in a closure |
2300 | */ |
2301 | public List<Type> insert(List<Type> cl, Type t) { |
2302 | if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) { |
2303 | return cl.prepend(t); |
2304 | } else if (cl.head.tsym.precedes(t.tsym, this)) { |
2305 | return insert(cl.tail, t).prepend(cl.head); |
2306 | } else { |
2307 | return cl; |
2308 | } |
2309 | } |
2310 | |
2311 | /** |
2312 | * Form the union of two closures |
2313 | */ |
2314 | public List<Type> union(List<Type> cl1, List<Type> cl2) { |
2315 | if (cl1.isEmpty()) { |
2316 | return cl2; |
2317 | } else if (cl2.isEmpty()) { |
2318 | return cl1; |
2319 | } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) { |
2320 | return union(cl1.tail, cl2).prepend(cl1.head); |
2321 | } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) { |
2322 | return union(cl1, cl2.tail).prepend(cl2.head); |
2323 | } else { |
2324 | return union(cl1.tail, cl2.tail).prepend(cl1.head); |
2325 | } |
2326 | } |
2327 | |
2328 | /** |
2329 | * Intersect two closures |
2330 | */ |
2331 | public List<Type> intersect(List<Type> cl1, List<Type> cl2) { |
2332 | if (cl1 == cl2) |
2333 | return cl1; |
2334 | if (cl1.isEmpty() || cl2.isEmpty()) |
2335 | return List.nil(); |
2336 | if (cl1.head.tsym.precedes(cl2.head.tsym, this)) |
2337 | return intersect(cl1.tail, cl2); |
2338 | if (cl2.head.tsym.precedes(cl1.head.tsym, this)) |
2339 | return intersect(cl1, cl2.tail); |
2340 | if (isSameType(cl1.head, cl2.head)) |
2341 | return intersect(cl1.tail, cl2.tail).prepend(cl1.head); |
2342 | if (cl1.head.tsym == cl2.head.tsym && |
2343 | cl1.head.tag == CLASS && cl2.head.tag == CLASS) { |
2344 | if (cl1.head.isParameterized() && cl2.head.isParameterized()) { |
2345 | Type merge = merge(cl1.head,cl2.head); |
2346 | return intersect(cl1.tail, cl2.tail).prepend(merge); |
2347 | } |
2348 | if (cl1.head.isRaw() || cl2.head.isRaw()) |
2349 | return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head)); |
2350 | } |
2351 | return intersect(cl1.tail, cl2.tail); |
2352 | } |
2353 | // where |
2354 | class TypePair { |
2355 | final Type t1; |
2356 | final Type t2; |
2357 | TypePair(Type t1, Type t2) { |
2358 | this.t1 = t1; |
2359 | this.t2 = t2; |
2360 | } |
2361 | @Override |
2362 | public int hashCode() { |
2363 | return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2); |
2364 | } |
2365 | @Override |
2366 | public boolean equals(Object obj) { |
2367 | if (!(obj instanceof TypePair)) |
2368 | return false; |
2369 | TypePair typePair = (TypePair)obj; |
2370 | return isSameType(t1, typePair.t1) |
2371 | && isSameType(t2, typePair.t2); |
2372 | } |
2373 | } |
2374 | Set<TypePair> mergeCache = new HashSet<TypePair>(); |
2375 | private Type merge(Type c1, Type c2) { |
2376 | ClassType class1 = (ClassType) c1; |
2377 | List<Type> act1 = class1.getTypeArguments(); |
2378 | ClassType class2 = (ClassType) c2; |
2379 | List<Type> act2 = class2.getTypeArguments(); |
2380 | ListBuffer<Type> merged = new ListBuffer<Type>(); |
2381 | List<Type> typarams = class1.tsym.type.getTypeArguments(); |
2382 | |
2383 | while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) { |
2384 | if (containsType(act1.head, act2.head)) { |
2385 | merged.append(act1.head); |
2386 | } else if (containsType(act2.head, act1.head)) { |
2387 | merged.append(act2.head); |
2388 | } else { |
2389 | TypePair pair = new TypePair(c1, c2); |
2390 | Type m; |
2391 | if (mergeCache.add(pair)) { |
2392 | m = new WildcardType(lub(upperBound(act1.head), |
2393 | upperBound(act2.head)), |
2394 | BoundKind.EXTENDS, |
2395 | syms.boundClass); |
2396 | mergeCache.remove(pair); |
2397 | } else { |
2398 | m = new WildcardType(syms.objectType, |
2399 | BoundKind.UNBOUND, |
2400 | syms.boundClass); |
2401 | } |
2402 | merged.append(m.withTypeVar(typarams.head)); |
2403 | } |
2404 | act1 = act1.tail; |
2405 | act2 = act2.tail; |
2406 | typarams = typarams.tail; |
2407 | } |
2408 | assert(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty()); |
2409 | return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym); |
2410 | } |
2411 | |
2412 | /** |
2413 | * Return the minimum type of a closure, a compound type if no |
2414 | * unique minimum exists. |
2415 | */ |
2416 | private Type compoundMin(List<Type> cl) { |
2417 | if (cl.isEmpty()) return syms.objectType; |
2418 | List<Type> compound = closureMin(cl); |
2419 | if (compound.isEmpty()) |
2420 | return null; |
2421 | else if (compound.tail.isEmpty()) |
2422 | return compound.head; |
2423 | else |
2424 | return makeCompoundType(compound); |
2425 | } |
2426 | |
2427 | /** |
2428 | * Return the minimum types of a closure, suitable for computing |
2429 | * compoundMin or glb. |
2430 | */ |
2431 | private List<Type> closureMin(List<Type> cl) { |
2432 | ListBuffer<Type> classes = lb(); |
2433 | ListBuffer<Type> interfaces = lb(); |
2434 | while (!cl.isEmpty()) { |
2435 | Type current = cl.head; |
2436 | if (current.isInterface()) |
2437 | interfaces.append(current); |
2438 | else |
2439 | classes.append(current); |
2440 | ListBuffer<Type> candidates = lb(); |
2441 | for (Type t : cl.tail) { |
2442 | if (!isSubtypeNoCapture(current, t)) |
2443 | candidates.append(t); |
2444 | } |
2445 | cl = candidates.toList(); |
2446 | } |
2447 | return classes.appendList(interfaces).toList(); |
2448 | } |
2449 | |
2450 | /** |
2451 | * Return the least upper bound of pair of types. if the lub does |
2452 | * not exist return null. |
2453 | */ |
2454 | public Type lub(Type t1, Type t2) { |
2455 | return lub(List.of(t1, t2)); |
2456 | } |
2457 | |
2458 | /** |
2459 | * Return the least upper bound (lub) of set of types. If the lub |
2460 | * does not exist return the type of null (bottom). |
2461 | */ |
2462 | public Type lub(List<Type> ts) { |
2463 | final int ARRAY_BOUND = 1; |
2464 | final int CLASS_BOUND = 2; |
2465 | int boundkind = 0; |
2466 | for (Type t : ts) { |
2467 | switch (t.tag) { |
2468 | case CLASS: |
2469 | boundkind |= CLASS_BOUND; |
2470 | break; |
2471 | case ARRAY: |
2472 | boundkind |= ARRAY_BOUND; |
2473 | break; |
2474 | case TYPEVAR: |
2475 | do { |
2476 | t = t.getUpperBound(); |
2477 | } while (t.tag == TYPEVAR); |
2478 | if (t.tag == ARRAY) { |
2479 | boundkind |= ARRAY_BOUND; |
2480 | } else { |
2481 | boundkind |= CLASS_BOUND; |
2482 | } |
2483 | break; |
2484 | default: |
2485 | if (t.isPrimitive()) |
2486 | return syms.botType; |
2487 | } |
2488 | } |
2489 | switch (boundkind) { |
2490 | case 0: |
2491 | return syms.botType; |
2492 | |
2493 | case ARRAY_BOUND: |
2494 | // calculate lub(A[], B[]) |
2495 | List<Type> elements = Type.map(ts, elemTypeFun); |
2496 | for (Type t : elements) { |
2497 | if (t.isPrimitive()) { |
2498 | // if a primitive type is found, then return |
2499 | // arraySuperType unless all the types are the |
2500 | // same |
2501 | Type first = ts.head; |
2502 | for (Type s : ts.tail) { |
2503 | if (!isSameType(first, s)) { |
2504 | // lub(int[], B[]) is Cloneable & Serializable |
2505 | return arraySuperType(); |
2506 | } |
2507 | } |
2508 | // all the array types are the same, return one |
2509 | // lub(int[], int[]) is int[] |
2510 | return first; |
2511 | } |
2512 | } |
2513 | // lub(A[], B[]) is lub(A, B)[] |
2514 | return new ArrayType(lub(elements), syms.arrayClass); |
2515 | |
2516 | case CLASS_BOUND: |
2517 | // calculate lub(A, B) |
2518 | while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR) |
2519 | ts = ts.tail; |
2520 | assert !ts.isEmpty(); |
2521 | List<Type> cl = closure(ts.head); |
2522 | for (Type t : ts.tail) { |
2523 | if (t.tag == CLASS || t.tag == TYPEVAR) |
2524 | cl = intersect(cl, closure(t)); |
2525 | } |
2526 | return compoundMin(cl); |
2527 | |
2528 | default: |
2529 | // calculate lub(A, B[]) |
2530 | List<Type> classes = List.of(arraySuperType()); |
2531 | for (Type t : ts) { |
2532 | if (t.tag != ARRAY) // Filter out any arrays |
2533 | classes = classes.prepend(t); |
2534 | } |
2535 | // lub(A, B[]) is lub(A, arraySuperType) |
2536 | return lub(classes); |
2537 | } |
2538 | } |
2539 | // where |
2540 | private Type arraySuperType = null; |
2541 | private Type arraySuperType() { |
2542 | // initialized lazily to avoid problems during compiler startup |
2543 | if (arraySuperType == null) { |
2544 | synchronized (this) { |
2545 | if (arraySuperType == null) { |
2546 | // JLS 10.8: all arrays implement Cloneable and Serializable. |
2547 | arraySuperType = makeCompoundType(List.of(syms.serializableType, |
2548 | syms.cloneableType), |
2549 | syms.objectType); |
2550 | } |
2551 | } |
2552 | } |
2553 | return arraySuperType; |
2554 | } |
2555 | // </editor-fold> |
2556 | |
2557 | // <editor-fold defaultstate="collapsed" desc="Greatest lower bound"> |
2558 | public Type glb(Type t, Type s) { |
2559 | if (s == null) |
2560 | return t; |
2561 | else if (isSubtypeNoCapture(t, s)) |
2562 | return t; |
2563 | else if (isSubtypeNoCapture(s, t)) |
2564 | return s; |
2565 | |
2566 | List<Type> closure = union(closure(t), closure(s)); |
2567 | List<Type> bounds = closureMin(closure); |
2568 | |
2569 | if (bounds.isEmpty()) { // length == 0 |
2570 | return syms.objectType; |
2571 | } else if (bounds.tail.isEmpty()) { // length == 1 |
2572 | return bounds.head; |
2573 | } else { // length > 1 |
2574 | int classCount = 0; |
2575 | for (Type bound : bounds) |
2576 | if (!bound.isInterface()) |
2577 | classCount++; |
2578 | if (classCount > 1) |
2579 | return syms.errType; |
2580 | } |
2581 | return makeCompoundType(bounds); |
2582 | } |
2583 | // </editor-fold> |
2584 | |
2585 | // <editor-fold defaultstate="collapsed" desc="hashCode"> |
2586 | /** |
2587 | * Compute a hash code on a type. |
2588 | */ |
2589 | public static int hashCode(Type t) { |
2590 | return hashCode.visit(t); |
2591 | } |
2592 | // where |
2593 | private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() { |
2594 | |
2595 | public Integer visitType(Type t, Void ignored) { |
2596 | return t.tag; |
2597 | } |
2598 | |
2599 | @Override |
2600 | public Integer visitClassType(ClassType t, Void ignored) { |
2601 | int result = visit(t.getEnclosingType()); |
2602 | result *= 127; |
2603 | result += t.tsym.flatName().hashCode(); |
2604 | for (Type s : t.getTypeArguments()) { |
2605 | result *= 127; |
2606 | result += visit(s); |
2607 | } |
2608 | return result; |
2609 | } |
2610 | |
2611 | @Override |
2612 | public Integer visitWildcardType(WildcardType t, Void ignored) { |
2613 | int result = t.kind.hashCode(); |
2614 | if (t.type != null) { |
2615 | result *= 127; |
2616 | result += visit(t.type); |
2617 | } |
2618 | return result; |
2619 | } |
2620 | |
2621 | @Override |
2622 | public Integer visitArrayType(ArrayType t, Void ignored) { |
2623 | return visit(t.elemtype) + 12; |
2624 | } |
2625 | |
2626 | @Override |
2627 | public Integer visitTypeVar(TypeVar t, Void ignored) { |
2628 | return System.identityHashCode(t.tsym); |
2629 | } |
2630 | |
2631 | @Override |
2632 | public Integer visitUndetVar(UndetVar t, Void ignored) { |
2633 | return System.identityHashCode(t); |
2634 | } |
2635 | |
2636 | @Override |
2637 | public Integer visitErrorType(ErrorType t, Void ignored) { |
2638 | return 0; |
2639 | } |
2640 | }; |
2641 | // </editor-fold> |
2642 | |
2643 | // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable"> |
2644 | /** |
2645 | * Does t have a result that is a subtype of the result type of s, |
2646 | * suitable for covariant returns? It is assumed that both types |
2647 | * are (possibly polymorphic) method types. Monomorphic method |
2648 | * types are handled in the obvious way. Polymorphic method types |
2649 | * require renaming all type variables of one to corresponding |
2650 | * type variables in the other, where correspondence is by |
2651 | * position in the type parameter list. */ |
2652 | public boolean resultSubtype(Type t, Type s, Warner warner) { |
2653 | List<Type> tvars = t.getTypeArguments(); |
2654 | List<Type> svars = s.getTypeArguments(); |
2655 | Type tres = t.getReturnType(); |
2656 | Type sres = subst(s.getReturnType(), svars, tvars); |
2657 | return covariantReturnType(tres, sres, warner); |
2658 | } |
2659 | |
2660 | /** |
2661 | * Return-Type-Substitutable. |
2662 | * @see <a href="http://java.sun.com/docs/books/jls/">The Java |
2663 | * Language Specification, Third Ed. (8.4.5)</a> |
2664 | */ |
2665 | public boolean returnTypeSubstitutable(Type r1, Type r2) { |
2666 | if (hasSameArgs(r1, r2)) |
2667 | return resultSubtype(r1, r2, Warner.noWarnings); |
2668 | else |
2669 | return covariantReturnType(r1.getReturnType(), |
2670 | erasure(r2.getReturnType()), |
2671 | Warner.noWarnings); |
2672 | } |
2673 | |
2674 | public boolean returnTypeSubstitutable(Type r1, |
2675 | Type r2, Type r2res, |
2676 | Warner warner) { |
2677 | if (isSameType(r1.getReturnType(), r2res)) |
2678 | return true; |
2679 | if (r1.getReturnType().isPrimitive() || r2res.isPrimitive()) |
2680 | return false; |
2681 | |
2682 | if (hasSameArgs(r1, r2)) |
2683 | return covariantReturnType(r1.getReturnType(), r2res, warner); |
2684 | if (!source.allowCovariantReturns()) |
2685 | return false; |
2686 | if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner)) |
2687 | return true; |
2688 | if (!isSubtype(r1.getReturnType(), erasure(r2res))) |
2689 | return false; |
2690 | warner.warnUnchecked(); |
2691 | return true; |
2692 | } |
2693 | |
2694 | /** |
2695 | * Is t an appropriate return type in an overrider for a |
2696 | * method that returns s? |
2697 | */ |
2698 | public boolean covariantReturnType(Type t, Type s, Warner warner) { |
2699 | return |
2700 | isSameType(t, s) || |
2701 | source.allowCovariantReturns() && |
2702 | !t.isPrimitive() && |
2703 | !s.isPrimitive() && |
2704 | isAssignable(t, s, warner); |
2705 | } |
2706 | // </editor-fold> |
2707 | |
2708 | // <editor-fold defaultstate="collapsed" desc="Box/unbox support"> |
2709 | /** |
2710 | * Return the class that boxes the given primitive. |
2711 | */ |
2712 | public ClassSymbol boxedClass(Type t) { |
2713 | return reader.enterClass(syms.boxedName[t.tag]); |
2714 | } |
2715 | |
2716 | /** |
2717 | * Return the primitive type corresponding to a boxed type. |
2718 | */ |
2719 | public Type unboxedType(Type t) { |
2720 | if (allowBoxing) { |
2721 | for (int i=0; i<syms.boxedName.length; i++) { |
2722 | Name box = syms.boxedName[i]; |
2723 | if (box != null && |
2724 | asSuper(t, reader.enterClass(box)) != null) |
2725 | return syms.typeOfTag[i]; |
2726 | } |
2727 | } |
2728 | return Type.noType; |
2729 | } |
2730 | // </editor-fold> |
2731 | |
2732 | // <editor-fold defaultstate="collapsed" desc="Capture conversion"> |
2733 | /* |
2734 | * JLS 3rd Ed. 5.1.10 Capture Conversion: |
2735 | * |
2736 | * Let G name a generic type declaration with n formal type |
2737 | * parameters A1 ... An with corresponding bounds U1 ... Un. There |
2738 | * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>, |
2739 | * where, for 1 <= i <= n: |
2740 | * |
2741 | * + If Ti is a wildcard type argument (4.5.1) of the form ? then |
2742 | * Si is a fresh type variable whose upper bound is |
2743 | * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null |
2744 | * type. |
2745 | * |
2746 | * + If Ti is a wildcard type argument of the form ? extends Bi, |
2747 | * then Si is a fresh type variable whose upper bound is |
2748 | * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is |
2749 | * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is |
2750 | * a compile-time error if for any two classes (not interfaces) |
2751 | * Vi and Vj,Vi is not a subclass of Vj or vice versa. |
2752 | * |
2753 | * + If Ti is a wildcard type argument of the form ? super Bi, |
2754 | * then Si is a fresh type variable whose upper bound is |
2755 | * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi. |
2756 | * |
2757 | * + Otherwise, Si = Ti. |
2758 | * |
2759 | * Capture conversion on any type other than a parameterized type |
2760 | * (4.5) acts as an identity conversion (5.1.1). Capture |
2761 | * conversions never require a special action at run time and |
2762 | * therefore never throw an exception at run time. |
2763 | * |
2764 | * Capture conversion is not applied recursively. |
2765 | */ |
2766 | /** |
2767 | * Capture conversion as specified by JLS 3rd Ed. |
2768 | */ |
2769 | public Type capture(Type t) { |
2770 | if (t.tag != CLASS) |
2771 | return t; |
2772 | ClassType cls = (ClassType)t; |
2773 | if (cls.isRaw() || !cls.isParameterized()) |
2774 | return cls; |
2775 | |
2776 | ClassType G = (ClassType)cls.asElement().asType(); |
2777 | List<Type> A = G.getTypeArguments(); |
2778 | List<Type> T = cls.getTypeArguments(); |
2779 | List<Type> S = freshTypeVariables(T); |
2780 | |
2781 | List<Type> currentA = A; |
2782 | List<Type> currentT = T; |
2783 | List<Type> currentS = S; |
2784 | boolean captured = false; |
2785 | while (!currentA.isEmpty() && |
2786 | !currentT.isEmpty() && |
2787 | !currentS.isEmpty()) { |
2788 | if (currentS.head != currentT.head) { |
2789 | captured = true; |
2790 | WildcardType Ti = (WildcardType)currentT.head; |
2791 | Type Ui = currentA.head.getUpperBound(); |
2792 | CapturedType Si = (CapturedType)currentS.head; |
2793 | if (Ui == null) |
2794 | Ui = syms.objectType; |
2795 | switch (Ti.kind) { |
2796 | case UNBOUND: |
2797 | Si.bound = subst(Ui, A, S); |
2798 | Si.lower = syms.botType; |
2799 | break; |
2800 | case EXTENDS: |
2801 | Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S)); |
2802 | Si.lower = syms.botType; |
2803 | break; |
2804 | case SUPER: |
2805 | Si.bound = subst(Ui, A, S); |
2806 | Si.lower = Ti.getSuperBound(); |
2807 | break; |
2808 | } |
2809 | if (Si.bound == Si.lower) |
2810 | currentS.head = Si.bound; |
2811 | } |
2812 | currentA = currentA.tail; |
2813 | currentT = currentT.tail; |
2814 | currentS = currentS.tail; |
2815 | } |
2816 | if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty()) |
2817 | return erasure(t); // some "rare" type involved |
2818 | |
2819 | if (captured) |
2820 | return new ClassType(cls.getEnclosingType(), S, cls.tsym); |
2821 | else |
2822 | return t; |
2823 | } |
2824 | // where |
2825 | private List<Type> freshTypeVariables(List<Type> types) { |
2826 | ListBuffer<Type> result = lb(); |
2827 | for (Type t : types) { |
2828 | if (t.tag == WILDCARD) { |
2829 | Type bound = ((WildcardType)t).getExtendsBound(); |
2830 | if (bound == null) |
2831 | bound = syms.objectType; |
2832 | result.append(new CapturedType(capturedName, |
2833 | syms.noSymbol, |
2834 | bound, |
2835 | syms.botType, |
2836 | (WildcardType)t)); |
2837 | } else { |
2838 | result.append(t); |
2839 | } |
2840 | } |
2841 | return result.toList(); |
2842 | } |
2843 | // </editor-fold> |
2844 | |
2845 | // <editor-fold defaultstate="collapsed" desc="Internal utility methods"> |
2846 | private List<Type> upperBounds(List<Type> ss) { |
2847 | if (ss.isEmpty()) return ss; |
2848 | Type head = upperBound(ss.head); |
2849 | List<Type> tail = upperBounds(ss.tail); |
2850 | if (head != ss.head || tail != ss.tail) |
2851 | return tail.prepend(head); |
2852 | else |
2853 | return ss; |
2854 | } |
2855 | |
2856 | private boolean sideCast(Type from, Type to, Warner warn) { |
2857 | // We are casting from type $from$ to type $to$, which are |
2858 | // non-final unrelated types. This method |
2859 | // tries to reject a cast by transferring type parameters |
2860 | // from $to$ to $from$ by common superinterfaces. |
2861 | boolean reverse = false; |
2862 | Type target = to; |
2863 | if ((to.tsym.flags() & INTERFACE) == 0) { |
2864 | assert (from.tsym.flags() & INTERFACE) != 0; |
2865 | reverse = true; |
2866 | to = from; |
2867 | from = target; |
2868 | } |
2869 | List<Type> commonSupers = superClosure(to, erasure(from)); |
2870 | boolean giveWarning = commonSupers.isEmpty(); |
2871 | // The arguments to the supers could be unified here to |
2872 | // get a more accurate analysis |
2873 | while (commonSupers.nonEmpty()) { |
2874 | Type t1 = asSuper(from, commonSupers.head.tsym); |
2875 | Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym); |
2876 | if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) |
2877 | return false; |
2878 | giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)); |
2879 | commonSupers = commonSupers.tail; |
2880 | } |
2881 | if (giveWarning && !isReifiable(to)) |
2882 | warn.warnUnchecked(); |
2883 | if (!source.allowCovariantReturns()) |
2884 | // reject if there is a common method signature with |
2885 | // incompatible return types. |
2886 | chk.checkCompatibleAbstracts(warn.pos(), from, to); |
2887 | return true; |
2888 | } |
2889 | |
2890 | private boolean sideCastFinal(Type from, Type to, Warner warn) { |
2891 | // We are casting from type $from$ to type $to$, which are |
2892 | // unrelated types one of which is final and the other of |
2893 | // which is an interface. This method |
2894 | // tries to reject a cast by transferring type parameters |
2895 | // from the final class to the interface. |
2896 | boolean reverse = false; |
2897 | Type target = to; |
2898 | if ((to.tsym.flags() & INTERFACE) == 0) { |
2899 | assert (from.tsym.flags() & INTERFACE) != 0; |
2900 | reverse = true; |
2901 | to = from; |
2902 | from = target; |
2903 | } |
2904 | assert (from.tsym.flags() & FINAL) != 0; |
2905 | Type t1 = asSuper(from, to.tsym); |
2906 | if (t1 == null) return false; |
2907 | Type t2 = to; |
2908 | if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) |
2909 | return false; |
2910 | if (!source.allowCovariantReturns()) |
2911 | // reject if there is a common method signature with |
2912 | // incompatible return types. |
2913 | chk.checkCompatibleAbstracts(warn.pos(), from, to); |
2914 | if (!isReifiable(target) && |
2915 | (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2))) |
2916 | warn.warnUnchecked(); |
2917 | return true; |
2918 | } |
2919 | |
2920 | private boolean giveWarning(Type from, Type to) { |
2921 | // To and from are (possibly different) parameterizations |
2922 | // of the same class or interface |
2923 | return to.isParameterized() && !containsType(to.getTypeArguments(), from.getTypeArguments()); |
2924 | } |
2925 | |
2926 | private List<Type> superClosure(Type t, Type s) { |
2927 | List<Type> cl = List.nil(); |
2928 | for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { |
2929 | if (isSubtype(s, erasure(l.head))) { |
2930 | cl = insert(cl, l.head); |
2931 | } else { |
2932 | cl = union(cl, superClosure(l.head, s)); |
2933 | } |
2934 | } |
2935 | return cl; |
2936 | } |
2937 | |
2938 | private boolean containsTypeEquivalent(Type t, Type s) { |
2939 | return |
2940 | isSameType(t, s) || // shortcut |
2941 | containsType(t, s) && containsType(s, t); |
2942 | } |
2943 | |
2944 | /** |
2945 | * Adapt a type by computing a substitution which maps a source |
2946 | * type to a target type. |
2947 | * |
2948 | * @param source the source type |
2949 | * @param target the target type |
2950 | * @param from the type variables of the computed substitution |
2951 | * @param to the types of the computed substitution. |
2952 | */ |
2953 | public void adapt(Type source, |
2954 | Type target, |
2955 | ListBuffer<Type> from, |
2956 | ListBuffer<Type> to) throws AdaptFailure { |
2957 | Map<Symbol,Type> mapping = new HashMap<Symbol,Type>(); |
2958 | adaptRecursive(source, target, from, to, mapping); |
2959 | List<Type> fromList = from.toList(); |
2960 | List<Type> toList = to.toList(); |
2961 | while (!fromList.isEmpty()) { |
2962 | Type val = mapping.get(fromList.head.tsym); |
2963 | if (toList.head != val) |
2964 | toList.head = val; |
2965 | fromList = fromList.tail; |
2966 | toList = toList.tail; |
2967 | } |
2968 | } |
2969 | // where |
2970 | private void adaptRecursive(Type source, |
2971 | Type target, |
2972 | ListBuffer<Type> from, |
2973 | ListBuffer<Type> to, |
2974 | Map<Symbol,Type> mapping) throws AdaptFailure { |
2975 | if (source.tag == TYPEVAR) { |
2976 | // Check to see if there is |
2977 | // already a mapping for $source$, in which case |
2978 | // the old mapping will be merged with the new |
2979 | Type val = mapping.get(source.tsym); |
2980 | if (val != null) { |
2981 | if (val.isSuperBound() && target.isSuperBound()) { |
2982 | val = isSubtype(lowerBound(val), lowerBound(target)) |
2983 | ? target : val; |
2984 | } else if (val.isExtendsBound() && target.isExtendsBound()) { |
2985 | val = isSubtype(upperBound(val), upperBound(target)) |
2986 | ? val : target; |
2987 | } else if (!isSameType(val, target)) { |
2988 | throw new AdaptFailure(); |
2989 | } |
2990 | } else { |
2991 | val = target; |
2992 | from.append(source); |
2993 | to.append(target); |
2994 | } |
2995 | mapping.put(source.tsym, val); |
2996 | } else if (source.tag == target.tag) { |
2997 | switch (source.tag) { |
2998 | case CLASS: |
2999 | adapt(source.allparams(), target.allparams(), |
3000 | from, to, mapping); |
3001 | break; |
3002 | case ARRAY: |
3003 | adaptRecursive(elemtype(source), elemtype(target), |
3004 | from, to, mapping); |
3005 | break; |
3006 | case WILDCARD: |
3007 | if (source.isExtendsBound()) { |
3008 | adaptRecursive(upperBound(source), upperBound(target), |
3009 | from, to, mapping); |
3010 | } else if (source.isSuperBound()) { |
3011 | adaptRecursive(lowerBound(source), lowerBound(target), |
3012 | from, to, mapping); |
3013 | } |
3014 | break; |
3015 | } |
3016 | } |
3017 | } |
3018 | public static class AdaptFailure extends Exception { |
3019 | static final long serialVersionUID = -7490231548272701566L; |
3020 | } |
3021 | |
3022 | /** |
3023 | * Adapt a type by computing a substitution which maps a list of |
3024 | * source types to a list of target types. |
3025 | * |
3026 | * @param source the source type |
3027 | * @param target the target type |
3028 | * @param from the type variables of the computed substitution |
3029 | * @param to the types of the computed substitution. |
3030 | */ |
3031 | private void adapt(List<Type> source, |
3032 | List<Type> target, |
3033 | ListBuffer<Type> from, |
3034 | ListBuffer<Type> to, |
3035 | Map<Symbol,Type> mapping) throws AdaptFailure { |
3036 | if (source.length() == target.length()) { |
3037 | while (source.nonEmpty()) { |
3038 | adaptRecursive(source.head, target.head, from, to, mapping); |
3039 | source = source.tail; |
3040 | target = target.tail; |
3041 | } |
3042 | } |
3043 | } |
3044 | |
3045 | private void adaptSelf(Type t, |
3046 | ListBuffer<Type> from, |
3047 | ListBuffer<Type> to) { |
3048 | try { |
3049 | //if (t.tsym.type != t) |
3050 | adapt(t.tsym.type, t, from, to); |
3051 | } catch (AdaptFailure ex) { |
3052 | // Adapt should never fail calculating a mapping from |
3053 | // t.tsym.type to t as there can be no merge problem. |
3054 | throw new AssertionError(ex); |
3055 | } |
3056 | } |
3057 | |
3058 | /** |
3059 | * Rewrite all type variables (universal quantifiers) in the given |
3060 | * type to wildcards (existential quantifiers). This is used to |
3061 | * determine if a cast is allowed. For example, if high is true |
3062 | * and {@code T <: Number}, then {@code List<T>} is rewritten to |
3063 | * {@code List<? extends Number>}. Since {@code List<Integer> <: |
3064 | * List<? extends Number>} a {@code List<T>} can be cast to {@code |
3065 | * List<Integer>} with a warning. |
3066 | * @param t a type |
3067 | * @param high if true return an upper bound; otherwise a lower |
3068 | * bound |
3069 | * @param rewriteTypeVars only rewrite captured wildcards if false; |
3070 | * otherwise rewrite all type variables |
3071 | * @return the type rewritten with wildcards (existential |
3072 | * quantifiers) only |
3073 | */ |
3074 | private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) { |
3075 | ListBuffer<Type> from = new ListBuffer<Type>(); |
3076 | ListBuffer<Type> to = new ListBuffer<Type>(); |
3077 | adaptSelf(t, from, to); |
3078 | ListBuffer<Type> rewritten = new ListBuffer<Type>(); |
3079 | List<Type> formals = from.toList(); |
3080 | boolean changed = false; |
3081 | for (Type arg : to.toList()) { |
3082 | Type bound; |
3083 | if (rewriteTypeVars && arg.tag == TYPEVAR) { |
3084 | TypeVar tv = (TypeVar)arg; |
3085 | bound = high ? tv.bound : syms.botType; |
3086 | } else { |
3087 | bound = high ? upperBound(arg) : lowerBound(arg); |
3088 | } |
3089 | Type newarg = bound; |
3090 | if (arg != bound) { |
3091 | changed = true; |
3092 | newarg = high ? makeExtendsWildcard(bound, (TypeVar)formals.head) |
3093 | : makeSuperWildcard(bound, (TypeVar)formals.head); |
3094 | } |
3095 | rewritten.append(newarg); |
3096 | formals = formals.tail; |
3097 | } |
3098 | if (changed) |
3099 | return subst(t.tsym.type, from.toList(), rewritten.toList()); |
3100 | else |
3101 | return t; |
3102 | } |
3103 | |
3104 | /** |
3105 | * Create a wildcard with the given upper (extends) bound; create |
3106 | * an unbounded wildcard if bound is Object. |
3107 | * |
3108 | * @param bound the upper bound |
3109 | * @param formal the formal type parameter that will be |
3110 | * substituted by the wildcard |
3111 | */ |
3112 | private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) { |
3113 | if (bound == syms.objectType) { |
3114 | return new WildcardType(syms.objectType, |
3115 | BoundKind.UNBOUND, |
3116 | syms.boundClass, |
3117 | formal); |
3118 | } else { |
3119 | return new WildcardType(bound, |
3120 | BoundKind.EXTENDS, |
3121 | syms.boundClass, |
3122 | formal); |
3123 | } |
3124 | } |
3125 | |
3126 | /** |
3127 | * Create a wildcard with the given lower (super) bound; create an |
3128 | * unbounded wildcard if bound is bottom (type of {@code null}). |
3129 | * |
3130 | * @param bound the lower bound |
3131 | * @param formal the formal type parameter that will be |
3132 | * substituted by the wildcard |
3133 | */ |
3134 | private WildcardType makeSuperWildcard(Type bound, TypeVar formal) { |
3135 | if (bound.tag == BOT) { |
3136 | return new WildcardType(syms.objectType, |
3137 | BoundKind.UNBOUND, |
3138 | syms.boundClass, |
3139 | formal); |
3140 | } else { |
3141 | return new WildcardType(bound, |
3142 | BoundKind.SUPER, |
3143 | syms.boundClass, |
3144 | formal); |
3145 | } |
3146 | } |
3147 | |
3148 | /** |
3149 | * A wrapper for a type that allows use in sets. |
3150 | */ |
3151 | class SingletonType { |
3152 | final Type t; |
3153 | SingletonType(Type t) { |
3154 | this.t = t; |
3155 | } |
3156 | public int hashCode() { |
3157 | return Types.this.hashCode(t); |
3158 | } |
3159 | public boolean equals(Object obj) { |
3160 | return (obj instanceof SingletonType) && |
3161 | isSameType(t, ((SingletonType)obj).t); |
3162 | } |
3163 | public String toString() { |
3164 | return t.toString(); |
3165 | } |
3166 | } |
3167 | // </editor-fold> |
3168 | |
3169 | // <editor-fold defaultstate="collapsed" desc="Visitors"> |
3170 | /** |
3171 | * A default visitor for types. All visitor methods except |
3172 | * visitType are implemented by delegating to visitType. Concrete |
3173 | * subclasses must provide an implementation of visitType and can |
3174 | * override other methods as needed. |
3175 | * |
3176 | * @param <R> the return type of the operation implemented by this |
3177 | * visitor; use Void if no return type is needed. |
3178 | * @param <S> the type of the second argument (the first being the |
3179 | * type itself) of the operation implemented by this visitor; use |
3180 | * Void if a second argument is not needed. |
3181 | */ |
3182 | public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> { |
3183 | final public R visit(Type t, S s) { return t.accept(this, s); } |
3184 | public R visitClassType(ClassType t, S s) { return visitType(t, s); } |
3185 | public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); } |
3186 | public R visitArrayType(ArrayType t, S s) { return visitType(t, s); } |
3187 | public R visitMethodType(MethodType t, S s) { return visitType(t, s); } |
3188 | public R visitPackageType(PackageType t, S s) { return visitType(t, s); } |
3189 | public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); } |
3190 | public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); } |
3191 | public R visitForAll(ForAll t, S s) { return visitType(t, s); } |
3192 | public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); } |
3193 | public R visitErrorType(ErrorType t, S s) { return visitType(t, s); } |
3194 | } |
3195 | |
3196 | /** |
3197 | * A <em>simple</em> visitor for types. This visitor is simple as |
3198 | * captured wildcards, for-all types (generic methods), and |
3199 | * undetermined type variables (part of inference) are hidden. |
3200 | * Captured wildcards are hidden by treating them as type |
3201 | * variables and the rest are hidden by visiting their qtypes. |
3202 | * |
3203 | * @param <R> the return type of the operation implemented by this |
3204 | * visitor; use Void if no return type is needed. |
3205 | * @param <S> the type of the second argument (the first being the |
3206 | * type itself) of the operation implemented by this visitor; use |
3207 | * Void if a second argument is not needed. |
3208 | */ |
3209 | public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> { |
3210 | @Override |
3211 | public R visitCapturedType(CapturedType t, S s) { |
3212 | return visitTypeVar(t, s); |
3213 | } |
3214 | @Override |
3215 | public R visitForAll(ForAll t, S s) { |
3216 | return visit(t.qtype, s); |
3217 | } |
3218 | @Override |
3219 | public R visitUndetVar(UndetVar t, S s) { |
3220 | return visit(t.qtype, s); |
3221 | } |
3222 | } |
3223 | |
3224 | /** |
3225 | * A plain relation on types. That is a 2-ary function on the |
3226 | * form Type × Type → Boolean. |
3227 | * <!-- In plain text: Type x Type -> Boolean --> |
3228 | */ |
3229 | public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {} |
3230 | |
3231 | /** |
3232 | * A convenience visitor for implementing operations that only |
3233 | * require one argument (the type itself), that is, unary |
3234 | * operations. |
3235 | * |
3236 | * @param <R> the return type of the operation implemented by this |
3237 | * visitor; use Void if no return type is needed. |
3238 | */ |
3239 | public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> { |
3240 | final public R visit(Type t) { return t.accept(this, null); } |
3241 | } |
3242 | |
3243 | /** |
3244 | * A visitor for implementing a mapping from types to types. The |
3245 | * default behavior of this class is to implement the identity |
3246 | * mapping (mapping a type to itself). This can be overridden in |
3247 | * subclasses. |
3248 | * |
3249 | * @param <S> the type of the second argument (the first being the |
3250 | * type itself) of this mapping; use Void if a second argument is |
3251 | * not needed. |
3252 | */ |
3253 | public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> { |
3254 | final public Type visit(Type t) { return t.accept(this, null); } |
3255 | public Type visitType(Type t, S s) { return t; } |
3256 | } |
3257 | // </editor-fold> |
3258 | } |