memberenter.java

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/*
 * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.tools.javac.comp;

import java.util.*;
import java.util.Set;
import javax.tools.JavaFileObject;

import com.sun.tools.javac.code.*;
import com.sun.tools.javac.jvm.*;
import com.sun.tools.javac.tree.*;
import com.sun.tools.javac.util.*;
import com.sun.tools.javac.util.List;

import com.sun.tools.javac.code.Type.*;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.tree.JCTree.*;

import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Kinds.*;
import static com.sun.tools.javac.code.TypeTags.*;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;

/** This is the second phase of Enter, in which classes are completed
 *  by entering their members into the class scope using
 *  MemberEnter.complete().  See Enter for an overview.
 *
 *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If
 *  you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class MemberEnter extends JCTree.Visitor implements Completer {
    protected static final Context.Key<MemberEnter> memberEnterKey =
        new Context.Key<MemberEnter>();

    /** A switch to determine whether we check for package/class conflicts
     */
    final static boolean checkClash = true;

    private final Name.Table names;
    private final Enter enter;
    private final Log log;
    private final Check chk;
    private final Attr attr;
    private final Symtab syms;
    private final TreeMaker make;
    private final ClassReader reader;
    private final Todo todo;
    private final Annotate annotate;
    private final Types types;
    private final Target target;

    private final boolean skipAnnotations;

    public static MemberEnter instance(Context context) {
        MemberEnter instance = context.get(memberEnterKey);
        if (instance == null)
            instance = new MemberEnter(context);
        return instance;
    }

    protected MemberEnter(Context context) {
        context.put(memberEnterKey, this);
        names = Name.Table.instance(context);
        enter = Enter.instance(context);
        log = Log.instance(context);
        chk = Check.instance(context);
        attr = Attr.instance(context);
        syms = Symtab.instance(context);
        make = TreeMaker.instance(context);
        reader = ClassReader.instance(context);
        todo = Todo.instance(context);
        annotate = Annotate.instance(context);
        types = Types.instance(context);
        target = Target.instance(context);
        skipAnnotations =
            Options.instance(context).get("skipAnnotations") != null;
    }

    /** A queue for classes whose members still need to be entered into the
     *  symbol table.
     */
    ListBuffer<Env<AttrContext>> halfcompleted = new ListBuffer<Env<AttrContext>>();

    /** Set to true only when the first of a set of classes is
     *  processed from the halfcompleted queue.
     */
    boolean isFirst = true;

    /** A flag to disable completion from time to time during member
     *  enter, as we only need to look up types.  This avoids
     *  unnecessarily deep recursion.
     */
    boolean completionEnabled = true;

    /* ---------- Processing import clauses ----------------
     */

    /** Import all classes of a class or package on demand.
     *  @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,
                           final TypeSymbol tsym,
                           Env<AttrContext> env) {
        // Check that packages imported from exist (JLS ???).
        if (tsym.kind == PCK && tsym.members().elems == null && !tsym.exists()) {
            // If we can't find java.lang, exit immediately.
            if (((PackageSymbol)tsym).fullname.equals(names.java_lang)) {
                JCDiagnostic msg = JCDiagnostic.fragment("fatal.err.no.java.lang");
                throw new FatalError(msg);
            } else {
                log.error(pos, "doesnt.exist", tsym);
            }
        }
        final Scope fromScope = tsym.members();
        final Scope toScope = env.toplevel.starImportScope;
        for (Scope.Entry e = fromScope.elems; e != null; e = e.sibling) {
            if (e.sym.kind == TYP && !toScope.includes(e.sym))
                toScope.enter(e.sym, fromScope);
        }
    }

    /** Import all static members of a class or package on demand.
     *  @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 importStaticAll(int pos,
                                 final TypeSymbol tsym,
                                 Env<AttrContext> env) {
        final JavaFileObject sourcefile = env.toplevel.sourcefile;
        final Scope toScope = env.toplevel.starImportScope;
        final PackageSymbol packge = env.toplevel.packge;
        final TypeSymbol origin = tsym;

        // enter imported types immediately
        new Object() {
            Set<Symbol> processed = new HashSet<Symbol>();
            void importFrom(TypeSymbol tsym) {
                if (tsym == null || !processed.add(tsym))
                    return;

                // also import inherited names
                importFrom(types.supertype(tsym.type).tsym);
                for (Type t : types.interfaces(tsym.type))
                    importFrom(t.tsym);

                final Scope fromScope = tsym.members();
                for (Scope.Entry e = fromScope.elems; e != null; e = e.sibling) {
                    Symbol sym = e.sym;
                    if (sym.kind == TYP &&
                        (sym.flags() & STATIC) != 0 &&
                        staticImportAccessible(sym, packge) &&
                        sym.isMemberOf(origin, types) &&
                        !toScope.includes(sym))
                        toScope.enter(sym, fromScope, origin.members());
                }
            }
        }.importFrom(tsym);

        // enter non-types before annotations that might use them
        annotate.earlier(new Annotate.Annotator() {
            Set<Symbol> processed = new HashSet<Symbol>();

            public String toString() {
                return "import static " + tsym + ".*" + " in " + sourcefile;
            }
            void importFrom(TypeSymbol tsym) {
                if (tsym == null || !processed.add(tsym))
                    return;

                // also import inherited names
                importFrom(types.supertype(tsym.type).tsym);
                for (Type t : types.interfaces(tsym.type))
                    importFrom(t.tsym);

                final Scope fromScope = tsym.members();
                for (Scope.Entry e = fromScope.elems; e != null; e = e.sibling) {
                    Symbol sym = e.sym;
                    if (sym.isStatic() && sym.kind != TYP &&
                        staticImportAccessible(sym, packge) &&
                        !toScope.includes(sym) &&
                        sym.isMemberOf(origin, types)) {
                        toScope.enter(sym, fromScope, origin.members());
                    }
                }
            }
            public void enterAnnotation() {
                importFrom(tsym);
            }
        });
    }

    // is the sym accessible everywhere in packge?
    boolean staticImportAccessible(Symbol sym, PackageSymbol packge) {
        int flags = (int)(sym.flags() & AccessFlags);
        switch (flags) {
        default:
        case PUBLIC:
            return true;
        case PRIVATE:
            return false;
        case 0:
        case PROTECTED:
            return sym.packge() == packge;
        }
    }

    /** Import statics types of a given name.  Non-types are handled in Attr.
     *  @param pos           Position to be used for error reporting.
     *  @param tsym          The class from which the name is imported.
     *  @param name          The (simple) name being imported.
     *  @param env           The environment containing the named import
     *                  scope to add to.
     */
    private void importNamedStatic(final DiagnosticPosition pos,
                                   final TypeSymbol tsym,
                                   final Name name,
                                   final Env<AttrContext> env) {
        if (tsym.kind != TYP) {
            log.error(pos, "static.imp.only.classes.and.interfaces");
            return;
        }

        final Scope toScope = env.toplevel.namedImportScope;
        final PackageSymbol packge = env.toplevel.packge;
        final TypeSymbol origin = tsym;

        // enter imported types immediately
        new Object() {
            Set<Symbol> processed = new HashSet<Symbol>();
            void importFrom(TypeSymbol tsym) {
                if (tsym == null || !processed.add(tsym))
                    return;

                // also import inherited names
                importFrom(types.supertype(tsym.type).tsym);
                for (Type t : types.interfaces(tsym.type))
                    importFrom(t.tsym);

                for (Scope.Entry e = tsym.members().lookup(name);
                     e.scope != null;
                     e = e.next()) {
                    Symbol sym = e.sym;
                    if (sym.isStatic() &&
                        sym.kind == TYP &&
                        staticImportAccessible(sym, packge) &&
                        sym.isMemberOf(origin, types) &&
                        chk.checkUniqueStaticImport(pos, sym, toScope))
                        toScope.enter(sym, sym.owner.members(), origin.members());
                }
            }
        }.importFrom(tsym);

        // enter non-types before annotations that might use them
        annotate.earlier(new Annotate.Annotator() {
            Set<Symbol> processed = new HashSet<Symbol>();
            boolean found = false;

            public String toString() {
                return "import static " + tsym + "." + name;
            }
            void importFrom(TypeSymbol tsym) {
                if (tsym == null || !processed.add(tsym))
                    return;

                // also import inherited names
                importFrom(types.supertype(tsym.type).tsym);
                for (Type t : types.interfaces(tsym.type))
                    importFrom(t.tsym);

                for (Scope.Entry e = tsym.members().lookup(name);
                     e.scope != null;
                     e = e.next()) {
                    Symbol sym = e.sym;
                    if (sym.isStatic() &&
                        staticImportAccessible(sym, packge) &&
                        sym.isMemberOf(origin, types)) {
                        found = true;
                        if (sym.kind == MTH ||
                            sym.kind != TYP && chk.checkUniqueStaticImport(pos, sym, toScope))
                            toScope.enter(sym, sym.owner.members(), origin.members());
                    }
                }
            }
            public void enterAnnotation() {
                JavaFileObject prev = log.useSource(env.toplevel.sourcefile);
                try {
                    importFrom(tsym);
                    if (!found) {
                        log.error(pos, "cant.resolve.location",
                                  JCDiagnostic.fragment("kindname.static"),
                                  name, "", "", Resolve.typeKindName(tsym.type),
                                  tsym.type);
                    }
                } finally {
                    log.useSource(prev);
                }
            }
        });
    }
    /** Import given class.
     *  @param pos           Position to be used for error reporting.
     *  @param tsym          The class to be imported.
     *  @param env           The environment containing the named import
     *                  scope to add to.
     */
    private void importNamed(DiagnosticPosition pos, Symbol tsym, Env<AttrContext> env) {
        if (tsym.kind == TYP &&
            chk.checkUniqueImport(pos, tsym, env.toplevel.namedImportScope))
            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<JCTypeParameter> typarams,
                   List<JCVariableDecl> params,
                   JCTree res,
                   List<JCExpression> thrown,
                   Env<AttrContext> env) {

        // Enter and attribute type parameters.
        List<Type> tvars = enter.classEnter(typarams, env);
        attr.attribTypeVariables(typarams, env);

        // Enter and attribute value parameters.
        ListBuffer<Type> argbuf = new ListBuffer<Type>();
        for (List<JCVariableDecl> l = params; l.nonEmpty(); l = l.tail) {
            memberEnter(l.head, env);
            argbuf.append(l.head.vartype.type);
        }

        // Attribute result type, if one is given.
        Type restype = res == null ? syms.voidType : attr.attribType(res, env);

        // Attribute thrown exceptions.