1 /*
2 * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.tools.java;
27
28 import java.util.Stack;
29 import java.io.IOException;
30 import sun.tools.tree.Context;
31 //JCOV
32 import java.io.File;
33 //end JCOV
34
35 /**
36 * This class defines the environment for a compilation.
37 * It is used to load classes, resolve class names and
38 * report errors. It is an abstract class, a subclass
39 * must define implementations for some of the functions.<p>
40 *
41 * An environment has a source object associated with it.
42 * This is the thing against which errors are reported, it
43 * is usually a file name, a field or a class.<p>
44 *
45 * Environments can be nested to change the source object.<p>
46 *
47 * WARNING: The contents of this source file are not part of any
48 * supported API. Code that depends on them does so at its own risk:
49 * they are subject to change or removal without notice.
50 *
51 * @author Arthur van Hoff
52 */
53
54 public class Environment implements Constants {
55 /**
56 * The actual environment to which everything is forwarded.
57 */
58 Environment env;
59
60 /**
61 * External character encoding name
62 */
63 String encoding;
64
65 /**
66 * The object that is currently being parsed/compiled.
67 * It is either a file name (String) or a field (MemberDefinition)
68 * or a class (ClassDeclaration or ClassDefinition).
69 */
70 Object source;
71
72 public Environment(Environment env, Object source) {
73 if (env != null && env.env != null && env.getClass() == this.getClass())
74 env = env.env; // a small optimization
75 this.env = env;
76 this.source = source;
77 }
78 public Environment() {
79 this(null, null);
80 }
81
82 /**
83 * Tells whether an Identifier refers to a package which should be
84 * exempt from the "exists" check in Imports#resolve().
85 */
86 public boolean isExemptPackage(Identifier id) {
87 return env.isExemptPackage(id);
88 }
89
90 /**
91 * Return a class declaration given a fully qualified class name.
92 */
93 public ClassDeclaration getClassDeclaration(Identifier nm) {
94 return env.getClassDeclaration(nm);
95 }
96
97 /**
98 * Return a class definition given a fully qualified class name.
99 * <p>
100 * Should be called only with 'internal' class names, i.e., the result
101 * of a call to 'resolveName' or a synthetic class name.
102 */
103 public final ClassDefinition getClassDefinition(Identifier nm) throws ClassNotFound {
104 if (nm.isInner()) {
105 ClassDefinition c = getClassDefinition(nm.getTopName());
106 Identifier tail = nm.getFlatName();
107 walkTail:
108 while (tail.isQualified()) {
109 tail = tail.getTail();
110 Identifier head = tail.getHead();
111 //System.out.println("CLASS: " + c + " HEAD: " + head + " TAIL: " + tail);
112 String hname = head.toString();
113 // If the name is of the form 'ClassName.N$localName', where N is
114 // a number, the field 'N$localName' may not necessarily be a member
115 // of the class named by 'ClassName', but might be a member of some
116 // inaccessible class contained within it. We use 'getLocalClass'
117 // to do the lookup in this case. This is part of a fix for bugid
118 // 4054523 and 4030421. See also 'BatchEnvironment.makeClassDefinition'.
119 // This should also work for anonymous class names of the form
120 // 'ClassName.N'. Note that the '.' qualifications get converted to
121 // '$' characters when determining the external name of the class and
122 // the name of the class file.
123 if (hname.length() > 0
124 && Character.isDigit(hname.charAt(0))) {
125 ClassDefinition localClass = c.getLocalClass(hname);
126 if (localClass != null) {
127 c = localClass;
128 continue walkTail;
129 }
130 } else {
131 for (MemberDefinition f = c.getFirstMatch(head);
132 f != null; f = f.getNextMatch()) {
133 if (f.isInnerClass()) {
134 c = f.getInnerClass();
135 continue walkTail;
136 }
137 }
138 }
139 throw new ClassNotFound(Identifier.lookupInner(c.getName(), head));
140 }
141 //System.out.println("FOUND " + c + " FOR " + nm);
142 return c;
143 }
144 return getClassDeclaration(nm).getClassDefinition(this);
145 }
146
147
148 /**
149 * Return a class declaration given a type. Only works for
150 * class types.
151 */
152 public ClassDeclaration getClassDeclaration(Type t) {
153 return getClassDeclaration(t.getClassName());
154 }
155
156 /**
157 * Return a class definition given a type. Only works for
158 * class types.
159 */
160 public final ClassDefinition getClassDefinition(Type t) throws ClassNotFound {
161 return getClassDefinition(t.getClassName());
162 }
163
164 /**
165 * Check if a class exists (without actually loading it).
166 * (Since inner classes cannot in general be examined without
167 * loading source, this method does not accept inner names.)
168 */
169 public boolean classExists(Identifier nm) {
170 return env.classExists(nm);
171 }
172
173 public final boolean classExists(Type t) {
174 return !t.isType(TC_CLASS) || classExists(t.getClassName());
175 }
176
177 /**
178 * Get the package path for a package
179 */
180 public Package getPackage(Identifier pkg) throws IOException {
181 return env.getPackage(pkg);
182 }
183
184 /**
185 * Load the definition of a class.
186 */
187 public void loadDefinition(ClassDeclaration c) {
188 env.loadDefinition(c);
189 }
190
191 /**
192 * Return the source of the environment (ie: the thing being compiled/parsed).
193 */
194 public final Object getSource() {
195 return source;
196 }
197
198 /**
199 * Resolve a type. Make sure that all the classes referred to by
200 * the type have a definition. Report errors. Return true if
201 * the type is well-formed. Presently used for types appearing
202 * in member declarations, which represent named types internally as
203 * qualified identifiers. Type names appearing in local variable
204 * declarations and within expressions are represented as identifier
205 * or field expressions, and are resolved by 'toType', which delegates
206 * handling of the non-inner portion of the name to this method.
207 * <p>
208 * In 'toType', the various stages of qualification are represented by
209 * separate AST nodes. Here, we are given a single identifier which
210 * contains the entire qualification structure. It is not possible in
211 * general to set the error location to the exact position of a component
212 * that is in error, so an error message must refer to the entire qualified
213 * name. An attempt to keep track of the string length of the components of
214 * the name and to offset the location accordingly fails because the initial
215 * prefix of the name may have been rewritten by an earlier call to
216 * 'resolveName'. See 'SourceMember.resolveTypeStructure'. The situation
217 * is actually even worse than this, because only a single location is
218 * passed in for an entire declaration, which may contain many type names.
219 * All error messages are thus poorly localized. These checks should be
220 * done while traversing the parse tree for the type, not the type descriptor.
221 * <p>
222 * DESIGN NOTE:
223 * As far as I can tell, the two-stage resolution of names represented in
224 * string form is an artifact of the late implementation of inner classes
225 * and the use of mangled names internally within the compiler. All
226 * qualified names should have their hiearchical structure made explicit
227 * in the parse tree at the phase at which they are presented for static
228 * semantic checking. This would affect class names appearing in 'extends',
229 * 'implements', and 'throws' clauses, as well as in member declarations.
230 */
231 public boolean resolve(long where, ClassDefinition c, Type t) {
232 switch (t.getTypeCode()) {
233 case TC_CLASS: {
234 ClassDefinition def;
235 try {
236 Identifier nm = t.getClassName();
237 if (!nm.isQualified() && !nm.isInner() && !classExists(nm)) {
238 resolve(nm); // elicit complaints about ambiguity
239 }
240 def = getQualifiedClassDefinition(where, nm, c, false);
241 if (!c.canAccess(this, def.getClassDeclaration())) {
242 // Reported error location may be imprecise
243 // if the name is qualified.
244 error(where, "cant.access.class", def);
245 return true; // return false later
246 }
247 def.noteUsedBy(c, where, env);
248 } catch (AmbiguousClass ee) {
249 error(where, "ambig.class", ee.name1, ee.name2);
250 return false;
251 } catch (ClassNotFound e) {
252 // For now, report "class.and.package" only when the code
253 // is going to fail anyway.
254 try {
255 if (e.name.isInner() &&
256 getPackage(e.name.getTopName()).exists()) {
257 env.error(where, "class.and.package",
258 e.name.getTopName());
259 }
260 } catch (IOException ee) {
261 env.error(where, "io.exception", "package check");
262 }
263 // This error message is also emitted for 'new' expressions.
264 // error(where, "class.not.found", e.name, "declaration");
265 error(where, "class.not.found.no.context", e.name);
266 return false;
267 }
268 return true;
269 }
270
271 case TC_ARRAY:
272 return resolve(where, c, t.getElementType());
273
274 case TC_METHOD:
275 boolean ok = resolve(where, c, t.getReturnType());
276 Type args[] = t.getArgumentTypes();
277 for (int i = args.length ; i-- > 0 ; ) {
278 ok &= resolve(where, c, args[i]);
279 }
280 return ok;
281 }
282 return true;
283 }
284
285 /**
286 * Given its fully-qualified name, verify that a class is defined and accessible.
287 * Used to check components of qualified names in contexts where a class is expected.
288 * Like 'resolve', but is given a single type name, not a type descriptor.
289 */
290 public boolean resolveByName(long where, ClassDefinition c, Identifier nm) {
291 return resolveByName(where, c, nm, false);
292 }
293
294 public boolean resolveExtendsByName(long where, ClassDefinition c, Identifier nm) {
295 return resolveByName(where, c, nm, true);
296 }
297
298 private boolean resolveByName(long where, ClassDefinition c,
299 Identifier nm, boolean isExtends) {
300 ClassDefinition def;
301 try {
302 if (!nm.isQualified() && !nm.isInner() && !classExists(nm)) {
303 resolve(nm); // elicit complaints about ambiguity
304 }
305 def = getQualifiedClassDefinition(where, nm, c, isExtends);
306 ClassDeclaration decl = def.getClassDeclaration();
307 if (!((!isExtends && c.canAccess(this, decl))
308 ||
309 (isExtends && c.extendsCanAccess(this, decl)))) {
310 error(where, "cant.access.class", def);
311 return true; // return false later
312 }
313 } catch (AmbiguousClass ee) {
314 error(where, "ambig.class", ee.name1, ee.name2);
315 return false;
316 } catch (ClassNotFound e) {
317 // For now, report "class.and.package" only when the code
318 // is going to fail anyway.
319 try {
320 if (e.name.isInner() &&
321 getPackage(e.name.getTopName()).exists()) {
322 env.error(where, "class.and.package",
323 e.name.getTopName());
324 }
325 } catch (IOException ee) {
326 env.error(where, "io.exception", "package check");
327 }
328 error(where, "class.not.found", e.name, "type name");
329 return false;
330 }
331 return true;
332 }
333
334 /**
335 * Like 'getClassDefinition(env)', but check access on each component.
336 * Currently called only by 'resolve' above. It is doubtful that calls
337 * to 'getClassDefinition(env)' are appropriate now.
338 */
339 public final ClassDefinition
340 getQualifiedClassDefinition(long where,
341 Identifier nm,
342 ClassDefinition ctxClass,
343 boolean isExtends) throws ClassNotFound {
344 if (nm.isInner()) {
345 ClassDefinition c = getClassDefinition(nm.getTopName());
346 Identifier tail = nm.getFlatName();
347 walkTail:
348 while (tail.isQualified()) {
349 tail = tail.getTail();
350 Identifier head = tail.getHead();
351 // System.out.println("CLASS: " + c + " HEAD: " + head + " TAIL: " + tail);
352 String hname = head.toString();
353 // Handle synthesized names of local and anonymous classes.
354 // See 'getClassDefinition(env)' above.
355 if (hname.length() > 0
356 && Character.isDigit(hname.charAt(0))) {
357 ClassDefinition localClass = c.getLocalClass(hname);
358 if (localClass != null) {
359 c = localClass;
360 continue walkTail;
361 }
362 } else {
363 for (MemberDefinition f = c.getFirstMatch(head);
364 f != null; f = f.getNextMatch()) {
365 if (f.isInnerClass()) {
366 ClassDeclaration rdecl = c.getClassDeclaration();
367 c = f.getInnerClass();
368 ClassDeclaration fdecl = c.getClassDeclaration();
369 // This check is presumably applicable even if the
370 // original source-code name (expanded by 'resolveNames')
371 // was a simple, unqualified name. Hopefully, JLS 2e
372 // will clarify the matter.
373 if ((!isExtends
374 && !ctxClass.canAccess(env, fdecl))
375 ||
376 (isExtends
377 && !ctxClass.extendsCanAccess(env, fdecl))) {
378 // Reported error location is imprecise.
379 env.error(where, "no.type.access", head, rdecl, ctxClass);
380 }
381 // The JLS 6.6.2 restrictions on access to protected members
382 // depend in an essential way upon the syntactic form of the name.
383 // Since the compiler has previously expanded the class names
384 // here into fully-qualified form ('resolveNames'), this check
385 // cannot be performed here. Unfortunately, the original names
386 // are clobbered during 'basicCheck', which is also the phase that
387 // resolves the inheritance structure, required to implement the
388 // access restrictions. Pending a large-scale revision of the
389 // name-resolution machinery, we forgo this check, with the result
390 // that the JLS 6.6.2 restrictions are not enforced for some cases
391 // of qualified access to inner classes. Some qualified names are
392 // resolved elsewhere via a different mechanism, and will be
393 // treated correctly -- see 'FieldExpression.checkCommon'.
394 /*---------------------------------------*
395 if (f.isProtected()) {
396 Type rty = Type.tClass(rdecl.getName()); // hack
397 if (!ctxClass.protectedAccess(env, f, rty)) {
398 // Reported error location is imprecise.
399 env.error(where, "invalid.protected.type.use",
400 head, ctxClass, rty);
401 }
402 }
403 *---------------------------------------*/
404 continue walkTail;
405 }
406 }
407 }
408 throw new ClassNotFound(Identifier.lookupInner(c.getName(), head));
409 }
410 //System.out.println("FOUND " + c + " FOR " + nm);
411 return c;
412 }
413 return getClassDeclaration(nm).getClassDefinition(this);
414 }
415
416 /**
417 * Resolve the names within a type, returning the adjusted type.
418 * Adjust class names to reflect scoping.
419 * Do not report errors.
420 * <p>
421 * NOTE: It would be convenient to check for errors here, such as
422 * verifying that each component of a qualified name exists and is
423 * accessible. Why must this be done in a separate phase?
424 * <p>
425 * If the 'synth' argument is true, indicating that the member whose
426 * type is being resolved is synthetic, names are resolved with respect
427 * to the package scope. (Fix for 4097882)
428 */
429 public Type resolveNames(ClassDefinition c, Type t, boolean synth) {
430 if (tracing) dtEvent("Environment.resolveNames: " + c + ", " + t);
431 switch (t.getTypeCode()) {
432 case TC_CLASS: {
433 Identifier name = t.getClassName();
434 Identifier rname;
435 if (synth) {
436 rname = resolvePackageQualifiedName(name);
437 } else {
438 rname = c.resolveName(this, name);
439 }
440 if (name != rname) {
441 t = Type.tClass(rname);
442 }
443 break;
444 }
445
446 case TC_ARRAY:
447 t = Type.tArray(resolveNames(c, t.getElementType(), synth));
448 break;
449
450 case TC_METHOD: {
451 Type ret = t.getReturnType();
452 Type rret = resolveNames(c, ret, synth);
453 Type args[] = t.getArgumentTypes();
454 Type rargs[] = new Type[args.length];
455 boolean changed = (ret != rret);
456 for (int i = args.length ; i-- > 0 ; ) {
457 Type arg = args[i];
458 Type rarg = resolveNames(c, arg, synth);
459 rargs[i] = rarg;
460 if (arg != rarg) {
461 changed = true;
462 }
463 }
464 if (changed) {
465 t = Type.tMethod(rret, rargs);
466 }
467 break;
468 }
469 }
470 return t;
471 }
472
473 /**
474 * Resolve a class name, using only package and import directives.
475 * Report no errors.
476 * <p>
477 */
478 public Identifier resolveName(Identifier name) {
479 // This logic is pretty exactly parallel to that of
480 // ClassDefinition.resolveName().
481 if (name.isQualified()) {
482 // Try to resolve the first identifier component,
483 // because inner class names take precedence over
484 // package prefixes. (Cf. ClassDefinition.resolveName.)
485 Identifier rhead = resolveName(name.getHead());
486
487 if (rhead.hasAmbigPrefix()) {
488 // The first identifier component refers to an
489 // ambiguous class. Limp on. We throw away the
490 // rest of the classname as it is irrelevant.
491 // (part of solution for 4059855).
492 return rhead;
493 }
494
495 if (!this.classExists(rhead)) {
496 return this.resolvePackageQualifiedName(name);
497 }
498 try {
499 return this.getClassDefinition(rhead).
500 resolveInnerClass(this, name.getTail());
501 } catch (ClassNotFound ee) {
502 // return partially-resolved name someone else can fail on
503 return Identifier.lookupInner(rhead, name.getTail());
504 }
505 }
506 try {
507 return resolve(name);
508 } catch (AmbiguousClass ee) {
509 // Don't force a resolution of the name if it is ambiguous.
510 // Forcing the resolution would tack the current package
511 // name onto the front of the class, which would be wrong.
512 // Instead, mark the name as ambiguous and let a later stage
513 // find the error by calling env.resolve(name).
514 // (part of solution for 4059855).
515
516 if (name.hasAmbigPrefix()) {
517 return name;
518 } else {
519 return name.addAmbigPrefix();
520 }
521 } catch (ClassNotFound ee) {
522 // last chance to make something halfway sensible
523 Imports imports = getImports();
524 if (imports != null)
525 return imports.forceResolve(this, name);
526 }
527 return name;
528 }
529
530 /**
531 * Discover if name consists of a package prefix, followed by the
532 * name of a class (that actually exists), followed possibly by
533 * some inner class names. If we can't find a class that exists,
534 * return the name unchanged.
535 * <p>
536 * This routine is used after a class name fails to
537 * be resolved by means of imports or inner classes.
538 * However, import processing uses this routine directly,
539 * since import names must be exactly qualified to start with.
540 */
541 public final Identifier resolvePackageQualifiedName(Identifier name) {
542 Identifier tail = null;
543 for (;;) {
544 if (classExists(name)) {
545 break;
546 }
547 if (!name.isQualified()) {
548 name = (tail == null) ? name : Identifier.lookup(name, tail);
549 tail = null;
550 break;
551 }
552 Identifier nm = name.getName();
553 tail = (tail == null)? nm: Identifier.lookup(nm, tail);
554 name = name.getQualifier();
555 }
556 if (tail != null)
557 name = Identifier.lookupInner(name, tail);
558 return name;
559 }
560
561 /**
562 * Resolve a class name, using only package and import directives.
563 */
564 public Identifier resolve(Identifier nm) throws ClassNotFound {
565 if (env == null) return nm; // a pretty useless no-op
566 return env.resolve(nm);
567 }
568
569 /**
570 * Get the imports used to resolve class names.
571 */
572 public Imports getImports() {
573 if (env == null) return null; // lame default
574 return env.getImports();
575 }
576
577 /**
578 * Create a new class.
579 */
580 public ClassDefinition makeClassDefinition(Environment origEnv, long where,
581 IdentifierToken name,
582 String doc, int modifiers,
583 IdentifierToken superClass,
584 IdentifierToken interfaces[],
585 ClassDefinition outerClass) {
586 if (env == null) return null; // lame default
587 return env.makeClassDefinition(origEnv, where, name,
588 doc, modifiers,
589 superClass, interfaces, outerClass);
590 }
591
592 /**
593 * Create a new field.
594 */
595 public MemberDefinition makeMemberDefinition(Environment origEnv, long where,
596 ClassDefinition clazz,
597 String doc, int modifiers,
598 Type type, Identifier name,
599 IdentifierToken argNames[],
600 IdentifierToken expIds[],
601 Object value) {
602 if (env == null) return null; // lame default
603 return env.makeMemberDefinition(origEnv, where, clazz, doc, modifiers,
604 type, name, argNames, expIds, value);
605 }
606
607 /**
608 * Returns true if the given method is applicable to the given arguments
609 */
610
611 public boolean isApplicable(MemberDefinition m, Type args[]) throws ClassNotFound {
612 Type mType = m.getType();
613 if (!mType.isType(TC_METHOD))
614 return false;
615 Type mArgs[] = mType.getArgumentTypes();
616 if (args.length != mArgs.length)
617 return false;
618 for (int i = args.length ; --i >= 0 ;)
619 if (!isMoreSpecific(args[i], mArgs[i]))
620 return false;
621 return true;
622 }
623
624
625 /**
626 * Returns true if "best" is in every argument at least as good as "other"
627 */
628 public boolean isMoreSpecific(MemberDefinition best, MemberDefinition other)
629 throws ClassNotFound {
630 Type bestType = best.getClassDeclaration().getType();
631 Type otherType = other.getClassDeclaration().getType();
632 boolean result = isMoreSpecific(bestType, otherType)
633 && isApplicable(other, best.getType().getArgumentTypes());
634 // System.out.println("isMoreSpecific: " + best + "/" + other
635 // + " => " + result);
636 return result;
637 }
638
639 /**
640 * Returns true if "from" is a more specific type than "to"
641 */
642
643 public boolean isMoreSpecific(Type from, Type to) throws ClassNotFound {
644 return implicitCast(from, to);
645 }
646
647 /**
648 * Return true if an implicit cast from this type to
649 * the given type is allowed.
650 */
651 @SuppressWarnings("fallthrough")
652 public boolean implicitCast(Type from, Type to) throws ClassNotFound {
653 if (from == to)
654 return true;
655
656 int toTypeCode = to.getTypeCode();
657
658 switch(from.getTypeCode()) {
659 case TC_BYTE:
660 if (toTypeCode == TC_SHORT)
661 return true;
662 case TC_SHORT:
663 case TC_CHAR:
664 if (toTypeCode == TC_INT) return true;
665 case TC_INT:
666 if (toTypeCode == TC_LONG) return true;
667 case TC_LONG:
668 if (toTypeCode == TC_FLOAT) return true;
669 case TC_FLOAT:
670 if (toTypeCode == TC_DOUBLE) return true;
671 case TC_DOUBLE:
672 default:
673 return false;
674
675 case TC_NULL:
676 return to.inMask(TM_REFERENCE);
677
678 case TC_ARRAY:
679 if (!to.isType(TC_ARRAY)) {
680 return (to == Type.tObject || to == Type.tCloneable
681 || to == Type.tSerializable);
682 } else {
683 // both are arrays. recurse down both until one isn't an array
684 do {
685 from = from.getElementType();
686 to = to.getElementType();
687 } while (from.isType(TC_ARRAY) && to.isType(TC_ARRAY));
688 if ( from.inMask(TM_ARRAY|TM_CLASS)
689 && to.inMask(TM_ARRAY|TM_CLASS)) {
690 return isMoreSpecific(from, to);
691 } else {
692 return (from.getTypeCode() == to.getTypeCode());
693 }
694 }
695
696 case TC_CLASS:
697 if (toTypeCode == TC_CLASS) {
698 ClassDefinition fromDef = getClassDefinition(from);
699 ClassDefinition toDef = getClassDefinition(to);
700 return toDef.implementedBy(this,
701 fromDef.getClassDeclaration());
702 } else {
703 return false;
704 }
705 }
706 }
707
708
709 /**
710 * Return true if an explicit cast from this type to
711 * the given type is allowed.
712 */
713 public boolean explicitCast(Type from, Type to) throws ClassNotFound {
714 if (implicitCast(from, to)) {
715 return true;
716 }
717 if (from.inMask(TM_NUMBER)) {
718 return to.inMask(TM_NUMBER);
719 }
720 if (from.isType(TC_CLASS) && to.isType(TC_CLASS)) {
721 ClassDefinition fromClass = getClassDefinition(from);
722 ClassDefinition toClass = getClassDefinition(to);
723 if (toClass.isFinal()) {
724 return fromClass.implementedBy(this,
725 toClass.getClassDeclaration());
726 }
727 if (fromClass.isFinal()) {
728 return toClass.implementedBy(this,
729 fromClass.getClassDeclaration());
730 }
731
732 // The code here used to omit this case. If both types
733 // involved in a cast are interfaces, then JLS 5.5 requires
734 // that we do a simple test -- make sure none of the methods
735 // in toClass and fromClass have the same signature but
736 // different return types. (bug number 4028359)
737 if (toClass.isInterface() && fromClass.isInterface()) {
738 return toClass.couldImplement(fromClass);
739 }
740
741 return toClass.isInterface() ||
742 fromClass.isInterface() ||
743 fromClass.superClassOf(this, toClass.getClassDeclaration());
744 }
745 if (to.isType(TC_ARRAY)) {
746 if (from.isType(TC_ARRAY)) {
747 Type t1 = from.getElementType();
748 Type t2 = to.getElementType();
749 while ((t1.getTypeCode() == TC_ARRAY)
750 && (t2.getTypeCode() == TC_ARRAY)) {
751 t1 = t1.getElementType();
752 t2 = t2.getElementType();
753 }
754 if (t1.inMask(TM_ARRAY|TM_CLASS) &&
755 t2.inMask(TM_ARRAY|TM_CLASS)) {
756 return explicitCast(t1, t2);
757 }
758 } else if (from == Type.tObject || from == Type.tCloneable
759 || from == Type.tSerializable)
760 return true;
761 }
762 return false;
763 }
764
765 /**
766 * Flags.
767 */
768 public int getFlags() {
769 return env.getFlags();
770 }
771
772 /**
773 * Debugging flags. There used to be a method debug()
774 * that has been replaced because -g has changed meaning
775 * (it now cooperates with -O and line number, variable
776 * range and source file info can be toggled separately).
777 */
778 public final boolean debug_lines() {
779 return (getFlags() & F_DEBUG_LINES) != 0;
780 }
781 public final boolean debug_vars() {
782 return (getFlags() & F_DEBUG_VARS) != 0;
783 }
784 public final boolean debug_source() {
785 return (getFlags() & F_DEBUG_SOURCE) != 0;
786 }
787
788 /**
789 * Optimization flags. There used to be a method optimize()
790 * that has been replaced because -O has changed meaning in
791 * javac to be replaced with -O and -O:interclass.
792 */
793 public final boolean opt() {
794 return (getFlags() & F_OPT) != 0;
795 }
796 public final boolean opt_interclass() {
797 return (getFlags() & F_OPT_INTERCLASS) != 0;
798 }
799
800 /**
801 * Verbose
802 */
803 public final boolean verbose() {
804 return (getFlags() & F_VERBOSE) != 0;
805 }
806
807 /**
808 * Dump debugging stuff
809 */
810 public final boolean dump() {
811 return (getFlags() & F_DUMP) != 0;
812 }
813
814 /**
815 * Verbose
816 */
817 public final boolean warnings() {
818 return (getFlags() & F_WARNINGS) != 0;
819 }
820
821 /**
822 * Dependencies
823 */
824 public final boolean dependencies() {
825 return (getFlags() & F_DEPENDENCIES) != 0;
826 }
827
828 /**
829 * Print Dependencies to stdout
830 */
831 public final boolean print_dependencies() {
832 return (getFlags() & F_PRINT_DEPENDENCIES) != 0;
833 }
834
835 /**
836 * Deprecation warnings are enabled.
837 */
838 public final boolean deprecation() {
839 return (getFlags() & F_DEPRECATION) != 0;
840 }
841
842 /**
843 * Do not support virtual machines before version 1.2.
844 * This option is not supported and is only here for testing purposes.
845 */
846 public final boolean version12() {
847 return (getFlags() & F_VERSION12) != 0;
848 }
849
850 /**
851 * Floating point is strict by default
852 */
853 public final boolean strictdefault() {
854 return (getFlags() & F_STRICTDEFAULT) != 0;
855 }
856
857 /**
858 * Release resources, if any.
859 */
860 public void shutdown() {
861 if (env != null) {
862 env.shutdown();
863 }
864 }
865
866 /**
867 * Issue an error.
868 * source - the input source, usually a file name string
869 * offset - the offset in the source of the error
870 * err - the error number (as defined in this interface)
871 * arg1 - an optional argument to the error (null if not applicable)
872 * arg2 - a second optional argument to the error (null if not applicable)
873 * arg3 - a third optional argument to the error (null if not applicable)
874 */
875 public void error(Object source, long where, String err, Object arg1, Object arg2, Object arg3) {
876 env.error(source, where, err, arg1, arg2, arg3);
877 }
878 public final void error(long where, String err, Object arg1, Object arg2, Object arg3) {
879 error(source, where, err, arg1, arg2, arg3);
880 }
881 public final void error(long where, String err, Object arg1, Object arg2) {
882 error(source, where, err, arg1, arg2, null);
883 }
884 public final void error(long where, String err, Object arg1) {
885 error(source, where, err, arg1, null, null);
886 }
887 public final void error(long where, String err) {
888 error(source, where, err, null, null, null);
889 }
890
891 /**
892 * Output a string. This can either be an error message or something
893 * for debugging. This should be used instead of println.
894 */
895 public void output(String msg) {
896 env.output(msg);
897 }
898
899 private static boolean debugging = (System.getProperty("javac.debug") != null);
900
901 public static void debugOutput(Object msg) {
902 if (Environment.debugging)
903 System.out.println(msg.toString());
904 }
905
906 /**
907 * set character encoding name
908 */
909 public void setCharacterEncoding(String encoding) {
910 this.encoding = encoding;
911 }
912
913 /**
914 * Return character encoding name
915 */
916 public String getCharacterEncoding() {
917 return encoding;
918 }
919
920 /**
921 * Return major version to use in generated class files.
922 */
923 public short getMajorVersion() {
924 if (env==null) return JAVA_DEFAULT_VERSION; // needed for javah
925 return env.getMajorVersion();
926 }
927
928 /**
929 * Return minor version to use in generated class files.
930 */
931 public short getMinorVersion() {
932 if (env==null) return JAVA_DEFAULT_MINOR_VERSION; // needed for javah
933 return env.getMinorVersion();
934 }
935
936 // JCOV
937 /**
938 * get coverage flag
939 */
940 public final boolean coverage() {
941 return (getFlags() & F_COVERAGE) != 0;
942 }
943
944 /**
945 * get flag of generation the coverage data file
946 */
947 public final boolean covdata() {
948 return (getFlags() & F_COVDATA) != 0;
949 }
950
951 /**
952 * Return the coverage data file
953 */
954 public File getcovFile() {
955 return env.getcovFile();
956 }
957
958 // end JCOV
959
960 /**
961 * Debug tracing.
962 * Currently, this code is used only for tracing the loading and
963 * checking of classes, particularly the demand-driven aspects.
964 * This code should probably be integrated with 'debugOutput' above,
965 * but we need to give more thought to the issue of classifying debugging
966 * messages and allowing those only those of interest to be enabled.
967 *
968 * Calls to these methods are generally conditioned on the final variable
969 * 'Constants.tracing', which allows the calls to be completely omitted
970 * in a production release to avoid space and time overhead.
971 */
972
973 private static boolean dependtrace =
974 (System.getProperty("javac.trace.depend") != null);
975
976 public void dtEnter(String s) {
977 if (dependtrace) System.out.println(">>> " + s);
978 }
979
980 public void dtExit(String s) {
981 if (dependtrace) System.out.println("<<< " + s);
982 }
983
984 public void dtEvent(String s) {
985 if (dependtrace) System.out.println(s);
986 }
987
988 /**
989 * Enable diagnostic dump of class modifier bits, including those
990 * in InnerClasses attributes, as they are written to the classfile.
991 * In the future, may also enable dumping field and method modifiers.
992 */
993
994 private static boolean dumpmodifiers =
995 (System.getProperty("javac.dump.modifiers") != null);
996
997 public boolean dumpModifiers() { return dumpmodifiers; }
998
999 }