enter.java

GJC（Generic Java Compiler）编译器

          *  @param pos	     Position to be used for error reporting.
          *  @param tsym	     The class or package the members of which are imported.
          *  @param toScope   The (import) scope in which imported classes
          *		     are entered.
          */
        private void importAll(int pos, TypeSymbol tsym, Env env) {
            if (tsym.kind == PCK && tsym.members().elems == null && !tsym.exists()) {
                if (((PackageSymbol) tsym).fullname.equals(names.java_lang)) {
                    String msg = Log.getLocalizedString("fatal.err.no.java.lang");
                    throw new FatalError(msg);
                } else {
                    log.error(pos, "doesnt.exist", tsym.toJava());
                }
            }
            Scope fromScope = tsym.members();
            Scope toScope = env.toplevel.starImportScope;
            for (Scope.Entry e = fromScope.elems; e != null; e = e.sibling)
                if (e.sym.kind == TYP && !isIncluded(e.sym, toScope))
                    toScope.enter(e.sym, fromScope);
        }

        /**
          * Import given class.
          *  @param pos	     Position to be used for error reporting.
          *  @param tsym	     The class to be imported.
          *  @param toScope   The (import) scope in which the imported class
          *		     is entered.
          */
        private void importNamed(int pos, Symbol tsym, Env env) {
            if (tsym.kind == TYP && checkUniqueImport(pos, tsym, env)) {
                env.toplevel.namedImportScope.enter(tsym, tsym.owner.members());
            }
        }

        /**
          * Construct method type from method signature.
          *  @param typarams    The method's type parameters.
          *  @param params      The method's value parameters.
          *  @param res	       The method's result type,
          *		       null if it is a constructor.
          *  @param thrown      The method's thrown exceptions.
          *  @param env	       The method's (local) environment.
          */
        Type signature(List typarams, List params, Tree res, List thrown, Env env) {
            ListBuffer argbuf = new ListBuffer();
            for (List l = params; l.nonEmpty(); l = l.tail)
                argbuf.append(attr.attribType(((Tree.VarDef) l.head).vartype, env));
            Type restype = res == null ? syms.voidType : attr.attribType(res, env);
            ListBuffer thrownbuf = new ListBuffer();
            for (List l = thrown; l.nonEmpty(); l = l.tail) {
                Type exc = attr.attribType((Tree) l.head, env);
                exc = chk.checkClassType(((Tree) l.head).pos, exc);
                thrownbuf.append(exc);
            }
            Type mtype = new MethodType(argbuf.toList(), restype, thrownbuf.toList(),
                    syms.methodClass);
            return mtype;
        }

        /**
          * Visitor argument: the current environment
          */
        protected Env env;

        /**
         * Visitor method: enter field and method definitions and process import
         *  clauses, catching any completion failure exceptions.
         */
        protected void memberEnter(Tree tree, Env env) {
            Env prevEnv = this.env;
            try {
                this.env = env;
                tree.accept(this);
            } catch (CompletionFailure ex) {
                chk.completionError(tree.pos, ex);
            }
            finally { this.env = prevEnv;
                    } }

        /**
          * Visitor method: enter members in a list of trees.
          */
        void memberEnter(List trees, Env env) {
            for (List l = trees; l.nonEmpty(); l = l.tail)
                memberEnter((Tree) l.head, env);
        }

        public void visitTopLevel(TopLevel tree) {
            if (tree.starImportScope.elems != null) {
                return;
            }
            if (checkClash && tree.pid != null) {
                Symbol p = tree.packge;
                while (p.owner != syms.rootPackage) {
                    p.owner.complete();
                    if (syms.classes.get(p.fullName()) != null) {
                        log.error(tree.pos, "pkg.clashes.with.class.of.same.name",
                                p.toJava());
                    }
                    p = p.owner;
                }
            }
            importAll(tree.pos, reader.enterPackage(names.java_lang), env);
            memberEnter(tree.defs, env);
        }

        public void visitImport(Import tree) {
            Tree imp = tree.qualid;
            Name name = TreeInfo.name(imp);
            TypeSymbol p;
            Env localEnv = env.dup(tree);
            assert completionEnabled;
            completionEnabled = false;
            if (imp.tag == Tree.SELECT) {
                Select s = (Select) imp;
                p = attr.attribTree(s.selected, localEnv, TYP | PCK, Type.noType).tsym;
                if (name == names.asterisk) {
                    chk.checkCanonical(s.selected);
                    importAll(tree.pos, p, env);
                } else {
                    TypeSymbol c = attr.attribType(imp, localEnv).tsym;
                    chk.checkCanonical(imp);
                    importNamed(tree.pos, c, env);
                }
            } else {
                assert false :
                "malformed import clause";
            }
            completionEnabled = true;
        }

        public void visitMethodDef(MethodDef tree) {
            Scope enclScope = enterScope(env);
            MethodSymbol m = new MethodSymbol(0, tree.name, null, enclScope.owner);
            m.flags_field = chk.checkFlags(tree.pos, tree.flags, m);
            tree.sym = m;
            Env localEnv = methodEnv(tree, env);
            m.type = signature(tree.typarams, tree.params, tree.restype,
                    tree.thrown, localEnv);
            ((AttrContext) localEnv.info).scope.leave();
            if (checkUnique(tree.pos, m, enclScope)) {
                checkNotReserved(tree.pos, tree.name);
                enclScope.enter(m);
            }
        }

        public void visitVarDef(VarDef tree) {
            Env localEnv = env;
            if ((tree.flags & STATIC) != 0) {
                localEnv = env.dup(tree, ((AttrContext) env.info).dup());
                ((AttrContext) localEnv.info).staticLevel++;
            }
            attr.attribType(tree.vartype, localEnv);
            Scope enclScope = enterScope(env);
            VarSymbol v =
                    new VarSymbol(0, tree.name, tree.vartype.type, enclScope.owner);
            v.flags_field = chk.checkFlags(tree.pos, tree.flags, v);
            tree.sym = v;
            if (tree.init != null) {
                v.flags_field |= HASINIT;
                if ((v.flags_field & FINAL) != 0)
                    v.constValue = initEnv(tree, env);
            }
            if (checkUnique(tree.pos, v, enclScope)) {
                checkNotReserved(tree.pos, tree.name);
                checkTransparentVar(tree.pos, v, enclScope);
                enclScope.enter(v);
            }
            v.pos = tree.pos;
        }

        /**
          * Default member enter visitor method: do nothing
          */
        public void visitTree(Tree tree) {
        }
    }

    /**
      * A completer class for source classes
      */
    class CompleteEnter implements Completer {

        CompleteEnter() {
            super();
        }

        /**
          * Complete entering a class.
          *  @param sym	   The symbol of the class to be completed.
          */
        public void complete(Symbol sym) throws CompletionFailure {
            if (!completionEnabled) {
                sym.completer = this;
                return;
            }
            ClassSymbol c = (ClassSymbol) sym;
            ClassType ct = (ClassType) c.type;
            Env env = (Env) classEnvs.get(c);
            ClassDef tree = (ClassDef) env.tree;
            Name prev = log.useSource(env.toplevel.sourcefile);
            boolean isFirst = halfcompleted.isEmpty();
            try {
                halfcompleted.append(env);
                if (c.owner.kind == PCK) {
                    phase2.memberEnter(env.toplevel, env.enclosing(Tree.TOPLEVEL));
                    todo.append(env);
                }
                try {
                    c.flags_field |= (LOCKED | UNATTRIBUTED);
                    if (c.owner.kind == TYP) {
                        c.owner = chk.checkNonCyclic(tree.pos, c.owner.type).tsym;
                        c.owner.complete();
                    }
                    Type supertype = (tree.extending != null) ?
                            attribBase(tree.extending, env, true, false) :
                            (c.fullname == names.java_lang_Object) ?
                            Type.noType : syms.objectType;
                    ListBuffer interfaces = new ListBuffer();
                    Set interfaceSet = Set.make();
                    for (List l = tree.implementing; l.nonEmpty(); l = l.tail) {
                        Type i = attribBase((Tree) l.head, env, false, true);
                        if (i.tag == CLASS) {
                            interfaces.append(i);
                            chk.checkNotRepeated(((Tree) l.head).pos, i,
                                    interfaceSet);
                        }
                    }
                    ct.supertype_field = supertype;
                    ct.interfaces_field = interfaces.toList();
                    if (c.fullname == names.java_lang_Object) {
                        if (tree.extending != null) {
                            chk.checkNonCyclic(tree.extending.pos, supertype);
                            ct.supertype_field = Type.noType;
                        } else if (tree.implementing.nonEmpty()) {
                            chk.checkNonCyclic( ((Tree) tree.implementing.head).pos,
                                    (Type) ct.interfaces_field.head);
                            ct.interfaces_field = Type.emptyList;
                        }
                    }
                }
                finally { c.flags_field &= ~LOCKED;
                        } attr.attribStats(tree.typarams, env);
                if ((c.flags() & INTERFACE) == 0 &&
                        !TreeInfo.hasConstructors(tree.defs)) {
                    List argtypes = Type.emptyList;
                    List thrown = Type.emptyList;
                    boolean based = false;
                    if (c.name.len == 0) {
                        NewClass nc = (NewClass) env.next.tree;
                        if (nc.constructor != null) {
                            Type superConstrType = c.type.memberType(nc.constructor);
                            argtypes = superConstrType.argtypes();
                            if (nc.encl != null) {
                                argtypes = argtypes.prepend(nc.encl.type);
                                based = true;
                            }
                            thrown = superConstrType.thrown();
                        }
                    }
                    Tree constrDef =
                            DefaultConstructor(make.at(tree.pos), c, argtypes,
                            thrown, based);
                    tree.defs = tree.defs.prepend(constrDef);
                }
                if ((c.flags_field & INTERFACE) == 0) {
                    VarSymbol thisSym =
                            new VarSymbol(FINAL | HASINIT, names._this, c.type, c);
                    thisSym.pos = Position.FIRSTPOS;
                    ((AttrContext) env.info).scope.enter(thisSym);
                    if (ct.supertype_field.tag == CLASS) {
                        VarSymbol superSym =
                                new VarSymbol(FINAL | HASINIT, names._super,
                                ct.supertype_field, c);
                        superSym.pos = Position.FIRSTPOS;
                        ((AttrContext) env.info).scope.enter(superSym);
                    }
                }
            } catch (CompletionFailure ex) {
                chk.completionError(tree.pos, ex);
            }
            if (checkClash && c.owner.kind == PCK && c.owner != syms.emptyPackage &&
                    reader.packageExists(c.fullname)) {
                log.error(tree.pos, "clash.with.pkg.of.same.name", c.toJava());
            }
            log.useSource(prev);
            if (isFirst) {
                while (halfcompleted.nonEmpty()) {
                    finish((Env) halfcompleted.next());
                }
            }
        }

        /**
          * Enter member fields and methods of a class
          *  @param env	  the environment current for the class block.
          */
        private void finish(Env env) {
            Name prev = log.useSource(env.toplevel.sourcefile);
            ClassDef tree = (ClassDef) env.tree;
            ClassSymbol c = tree.sym;
            phase2.memberEnter(tree.defs, env);
            log.useSource(prev);
        }

        /**
          * Attribute extended or implemented type reference, and check
          *  for cyclic references.
          *  @param tree		 The tree expressing the type reference.At
          *  @param env		 The environment current at the type reference.
          *  @param classExpected     true if only a class is expected here.
          *  @param interfaceExpected true if only an interface is expected here.
          */
        private Type attribBase(Tree tree, Env env, boolean classExpected,
                boolean interfaceExpected) {
            Type t = attr.attribBase(tree, env, classExpected, interfaceExpected);
            return chk.checkNonCyclic(tree.pos, t);
        }
    }
}