jdk8-mips64-public/langtools: src/share/classes/com/sun/tools/javac/code/Scope.java@ca5783d9a597 (annotated)

src/share/classes/com/sun/tools/javac/code/Scope.java@ca5783d9a597 (annotated)

src/share/classes/com/sun/tools/javac/code/Scope.java

Mon, 16 Oct 2017 16:07:48 +0800

author: aoqi
date: Mon, 16 Oct 2017 16:07:48 +0800
changeset 2893: ca5783d9a597
parent 2812: 9ec429ab0e7e
parent 2525: 2eb010b6cb22
permissions: -rw-r--r--

merge

 /*
  * Copyright (c) 1999, 2015, Oracle and/or its affiliates. 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.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package com.sun.tools.javac.code;
 import java.util.Iterator;
 import com.sun.tools.javac.util.*;
 /** A scope represents an area of visibility in a Java program. The
  *  Scope class is a container for symbols which provides
  *  efficient access to symbols given their names. Scopes are implemented
  *  as hash tables with "open addressing" and "double hashing".
  *  Scopes can be nested; the next field of a scope points
  *  to its next outer scope. Nested scopes can share their hash tables.
  *
  *  <p><b>This is NOT part of any supported API.
  *  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 Scope {
     /** The number of scopes that share this scope's hash table.
      */
     private int shared;
     /** Next enclosing scope (with whom this scope may share a hashtable)
      */
     public Scope next;
     /** The scope's owner.
      */
     public Symbol owner;
     /** A hash table for the scope's entries.
      */
     Entry[] table;
     /** Mask for hash codes, always equal to (table.length - 1).
      */
     int hashMask;
     /** A linear list that also contains all entries in
      *  reverse order of appearance (i.e later entries are pushed on top).
      */
     public Entry elems;
     /** The number of elements in this scope.
      * This includes deleted elements, whose value is the sentinel.
      */
     int nelems = 0;
     /** A list of scopes to be notified if items are to be removed from this scope.
      */
     List<ScopeListener> listeners = List.nil();
     /** Use as a "not-found" result for lookup.
      * Also used to mark deleted entries in the table.
      */
     private static final Entry sentinel = new Entry(null, null, null, null);
     /** The hash table's initial size.
      */
     private static final int INITIAL_SIZE = 0x10;
     /** A value for the empty scope.
      */
     public static final Scope emptyScope = new Scope(null, null, new Entry[]{});
     /** Construct a new scope, within scope next, with given owner, using
      *  given table. The table's length must be an exponent of 2.
      */
     private Scope(Scope next, Symbol owner, Entry[] table) {
         this.next = next;
         Assert.check(emptyScope == null || owner != null);
         this.owner = owner;
         this.table = table;
         this.hashMask = table.length - 1;
     }
     /** Convenience constructor used for dup and dupUnshared. */
     private Scope(Scope next, Symbol owner, Entry[] table, int nelems) {
         this(next, owner, table);
         this.nelems = nelems;
     }
     /** Construct a new scope, within scope next, with given owner,
      *  using a fresh table of length INITIAL_SIZE.
      */
     public Scope(Symbol owner) {
         this(null, owner, new Entry[INITIAL_SIZE]);
     }
     /** Construct a fresh scope within this scope, with same owner,
      *  which shares its table with the outer scope. Used in connection with
      *  method leave if scope access is stack-like in order to avoid allocation
      *  of fresh tables.
      */
     public Scope dup() {
         return dup(this.owner);
     }
     /** Construct a fresh scope within this scope, with new owner,
      *  which shares its table with the outer scope. Used in connection with
      *  method leave if scope access is stack-like in order to avoid allocation
      *  of fresh tables.
      */
     public Scope dup(Symbol newOwner) {
         Scope result = new Scope(this, newOwner, this.table, this.nelems);
         shared++;
         // System.out.println("====> duping scope " + this.hashCode() + " owned by " + newOwner + " to " + result.hashCode());
         // new Error().printStackTrace(System.out);
         return result;
     }
     /** Construct a fresh scope within this scope, with same owner,
      *  with a new hash table, whose contents initially are those of
      *  the table of its outer scope.
      */
     public Scope dupUnshared() {
         return new Scope(this, this.owner, this.table.clone(), this.nelems);
     }
     /** Remove all entries of this scope from its table, if shared
      *  with next.
      */
     public Scope leave() {
         Assert.check(shared == 0);
         if (table != next.table) return next;
         while (elems != null) {
             int hash = getIndex(elems.sym.name);
             Entry e = table[hash];
             Assert.check(e == elems, elems.sym);
             table[hash] = elems.shadowed;
             elems = elems.sibling;
         }
         Assert.check(next.shared > 0);
         next.shared--;
         next.nelems = nelems;
         // System.out.println("====> leaving scope " + this.hashCode() + " owned by " + this.owner + " to " + next.hashCode());
         // new Error().printStackTrace(System.out);
         return next;
     }
     /** Double size of hash table.
      */
     private void dble() {
         Assert.check(shared == 0);
         Entry[] oldtable = table;
         Entry[] newtable = new Entry[oldtable.length * 2];
         for (Scope s = this; s != null; s = s.next) {
             if (s.table == oldtable) {
                 Assert.check(s == this || s.shared != 0);
                 s.table = newtable;
                 s.hashMask = newtable.length - 1;
             }
         }
         int n = 0;
         for (int i = oldtable.length; --i >= 0; ) {
             Entry e = oldtable[i];
             if (e != null && e != sentinel) {
                 table[getIndex(e.sym.name)] = e;
                 n++;
             }
         }
         // We don't need to update nelems for shared inherited scopes,
         // since that gets handled by leave().
         nelems = n;
     }
     /** Enter symbol sym in this scope.
      */
     public void enter(Symbol sym) {
         Assert.check(shared == 0);
         enter(sym, this);
     }
     public void enter(Symbol sym, Scope s) {
         enter(sym, s, s, false);
     }
     /**
      * Enter symbol sym in this scope, but mark that it comes from
      * given scope `s' accessed through `origin'.  The last two
      * arguments are only used in import scopes.
      */
     public void enter(Symbol sym, Scope s, Scope origin, boolean staticallyImported) {
         Assert.check(shared == 0);
         if (nelems * 3 >= hashMask * 2)
             dble();
         int hash = getIndex(sym.name);
         Entry old = table[hash];
         if (old == null) {
             old = sentinel;
             nelems++;
         }
         Entry e = makeEntry(sym, old, elems, s, origin, staticallyImported);
         table[hash] = e;
         elems = e;
         //notify listeners
         for (List<ScopeListener> l = listeners; l.nonEmpty(); l = l.tail) {
             l.head.symbolAdded(sym, this);
         }
     }
     Entry makeEntry(Symbol sym, Entry shadowed, Entry sibling, Scope scope, Scope origin, boolean staticallyImported) {
         return new Entry(sym, shadowed, sibling, scope);
     }
     public interface ScopeListener {
         public void symbolAdded(Symbol sym, Scope s);
         public void symbolRemoved(Symbol sym, Scope s);
     }
     public void addScopeListener(ScopeListener sl) {
         listeners = listeners.prepend(sl);
     }
     /** Remove symbol from this scope.
      */
     public void remove(final Symbol sym) {
         Assert.check(shared == 0);
         Entry e = lookup(sym.name, new Filter<Symbol>() {
             @Override
             public boolean accepts(Symbol candidate) {
                 return candidate == sym;
             }
         });
         if (e.scope == null) return;
         // remove e from table and shadowed list;
         int i = getIndex(sym.name);
         Entry te = table[i];
         if (te == e)
             table[i] = e.shadowed;
         else while (true) {
             if (te.shadowed == e) {
                 te.shadowed = e.shadowed;
                 break;
             }
             te = te.shadowed;
         }
         // remove e from elems and sibling list
         te = elems;
         if (te == e)
             elems = e.sibling;
         else while (true) {
             if (te.sibling == e) {
                 te.sibling = e.sibling;
                 break;
             }
             te = te.sibling;
         }
         //notify listeners
         for (List<ScopeListener> l = listeners; l.nonEmpty(); l = l.tail) {
             l.head.symbolRemoved(sym, this);
         }
     }
     /** Enter symbol sym in this scope if not already there.
      */
     public void enterIfAbsent(Symbol sym) {
         Assert.check(shared == 0);
         Entry e = lookup(sym.name);
         while (e.scope == this && e.sym.kind != sym.kind) e = e.next();
         if (e.scope != this) enter(sym);
     }
     /** Given a class, is there already a class with same fully
      *  qualified name in this (import) scope?
      */
     public boolean includes(Symbol c) {
         for (Scope.Entry e = lookup(c.name);
              e.scope == this;
              e = e.next()) {
             if (e.sym == c) return true;
         }
         return false;
     }
     static final Filter<Symbol> noFilter = new Filter<Symbol>() {
         public boolean accepts(Symbol s) {
             return true;
         }
     };
     /** Return the entry associated with given name, starting in
      *  this scope and proceeding outwards. If no entry was found,
      *  return the sentinel, which is characterized by having a null in
      *  both its scope and sym fields, whereas both fields are non-null
      *  for regular entries.
      */
     public Entry lookup(Name name) {
         return lookup(name, noFilter);
     }
     public Entry lookup(Name name, Filter<Symbol> sf) {
         Entry e = table[getIndex(name)];
         if (e == null || e == sentinel)
             return sentinel;
         while (e.scope != null && (e.sym.name != name || !sf.accepts(e.sym)))
             e = e.shadowed;
         return e;
     }
     /*void dump (java.io.PrintStream out) {
         out.println(this);
         for (int l=0; l < table.length; l++) {
             Entry le = table[l];
             out.print("#"+l+": ");
             if (le==sentinel) out.println("sentinel");
             else if(le == null) out.println("null");
             else out.println(""+le+" s:"+le.sym);
         }
     }*/
     /** Look for slot in the table.
      *  We use open addressing with double hashing.
      */
     int getIndex (Name name) {
         int h = name.hashCode();
         int i = h & hashMask;
         // The expression below is always odd, so it is guaranteed
         // to be mutually prime with table.length, a power of 2.
         int x = hashMask - ((h + (h >> 16)) << 1);
         int d = -1; // Index of a deleted item.
         for (;;) {
             Entry e = table[i];
             if (e == null)
                 return d >= 0 ? d : i;
             if (e == sentinel) {
                 // We have to keep searching even if we see a deleted item.
                 // However, remember the index in case we fail to find the name.
                 if (d < 0)
                     d = i;
             } else if (e.sym.name == name)
                 return i;
             i = (i + x) & hashMask;
         }
     }
     public boolean anyMatch(Filter<Symbol> sf) {
         return getElements(sf).iterator().hasNext();
     }
     public Iterable<Symbol> getElements() {
         return getElements(noFilter);
     }
     public Iterable<Symbol> getElements(final Filter<Symbol> sf) {
         return new Iterable<Symbol>() {
             public Iterator<Symbol> iterator() {
                 return new Iterator<Symbol>() {
                     private Scope currScope = Scope.this;
                     private Scope.Entry currEntry = elems;
                     {
                         update();
                     }
                     public boolean hasNext() {
                         return currEntry != null;
                     }
                     public Symbol next() {
                         Symbol sym = (currEntry == null ? null : currEntry.sym);
                         if (currEntry != null) {
                             currEntry = currEntry.sibling;
                         }
                         update();
                         return sym;
                     }
                     public void remove() {
                         throw new UnsupportedOperationException();
                     }
                     private void update() {
                         skipToNextMatchingEntry();
                         while (currEntry == null && currScope.next != null) {
                             currScope = currScope.next;
                             currEntry = currScope.elems;
                             skipToNextMatchingEntry();
                         }
                     }
                     void skipToNextMatchingEntry() {
                         while (currEntry != null && !sf.accepts(currEntry.sym)) {
                             currEntry = currEntry.sibling;
                         }
                     }
                 };
             }
         };
     }
     public Iterable<Symbol> getElementsByName(Name name) {
         return getElementsByName(name, noFilter);
     }
     public Iterable<Symbol> getElementsByName(final Name name, final Filter<Symbol> sf) {
         return new Iterable<Symbol>() {
             public Iterator<Symbol> iterator() {
                  return new Iterator<Symbol>() {
                     Scope.Entry currentEntry = lookup(name, sf);
                     public boolean hasNext() {
                         return currentEntry.scope != null;
                     }
                     public Symbol next() {
                         Scope.Entry prevEntry = currentEntry;
                         currentEntry = currentEntry.next(sf);
                         return prevEntry.sym;
                     }
                     public void remove() {
                         throw new UnsupportedOperationException();
                     }
                 };
             }
         };
     }
     public String toString() {
         StringBuilder result = new StringBuilder();
         result.append("Scope[");
         for (Scope s = this; s != null ; s = s.next) {
             if (s != this) result.append(" | ");
             for (Entry e = s.elems; e != null; e = e.sibling) {
                 if (e != s.elems) result.append(", ");
                 result.append(e.sym);
             }
         }
         result.append("]");
         return result.toString();
     }
     /** A class for scope entries.
      */
     public static class Entry {
         /** The referenced symbol.
          *  sym == null   iff   this == sentinel
          */
         public Symbol sym;
         /** An entry with the same hash code, or sentinel.
          */
         private Entry shadowed;
         /** Next entry in same scope.
          */
         public Entry sibling;
         /** The entry's scope.
          *  scope == null   iff   this == sentinel
          *  for an entry in an import scope, this is the scope
          *  where the entry came from (i.e. was imported from).
          */
         public Scope scope;
         public Entry(Symbol sym, Entry shadowed, Entry sibling, Scope scope) {
             this.sym = sym;
             this.shadowed = shadowed;
             this.sibling = sibling;
             this.scope = scope;
         }
         /** Return next entry with the same name as this entry, proceeding
          *  outwards if not found in this scope.
          */
         public Entry next() {
             return shadowed;
         }
         public Entry next(Filter<Symbol> sf) {
             if (shadowed.sym == null || sf.accepts(shadowed.sym)) return shadowed;
             else return shadowed.next(sf);
         }
         public boolean isStaticallyImported() {
             return false;
         }
         public Scope getOrigin() {
             // The origin is only recorded for import scopes.  For all
             // other scope entries, the "enclosing" type is available
             // from other sources.  See Attr.visitSelect and
             // Attr.visitIdent.  Rather than throwing an assertion
             // error, we return scope which will be the same as origin
             // in many cases.
             return scope;
         }
     }
     public static class ImportScope extends Scope {
         public ImportScope(Symbol owner) {
             super(owner);
         }
         @Override
         Entry makeEntry(Symbol sym, Entry shadowed, Entry sibling, Scope scope,
                 final Scope origin, final boolean staticallyImported) {
             return new Entry(sym, shadowed, sibling, scope) {
                 @Override
                 public Scope getOrigin() {
                     return origin;
                 }
                 @Override
                 public boolean isStaticallyImported() {
                     return staticallyImported;
                 }
             };
         }
     }
     public static class StarImportScope extends ImportScope implements ScopeListener {
         public StarImportScope(Symbol owner) {
             super(owner);
         }
         public void importAll (Scope fromScope) {
             for (Scope.Entry e = fromScope.elems; e != null; e = e.sibling) {
                 if (e.sym.kind == Kinds.TYP && !includes(e.sym))
                     enter(e.sym, fromScope);
             }
             // Register to be notified when imported items are removed
             fromScope.addScopeListener(this);
         }
         public void symbolRemoved(Symbol sym, Scope s) {
             remove(sym);
         }
         public void symbolAdded(Symbol sym, Scope s) { }
     }
     /** An empty scope, into which you can't place anything.  Used for
      *  the scope for a variable initializer.
      */
     public static class DelegatedScope extends Scope {
         Scope delegatee;
         public static final Entry[] emptyTable = new Entry[0];
         public DelegatedScope(Scope outer) {
             super(outer, outer.owner, emptyTable);
             delegatee = outer;
         }
         public Scope dup() {
             return new DelegatedScope(next);
         }
         public Scope dupUnshared() {
             return new DelegatedScope(next);
         }
         public Scope leave() {
             return next;
         }
         public void enter(Symbol sym) {
             // only anonymous classes could be put here
         }
         public void enter(Symbol sym, Scope s) {
             // only anonymous classes could be put here
         }
         public void remove(Symbol sym) {
             throw new AssertionError(sym);
         }
         public Entry lookup(Name name) {
             return delegatee.lookup(name);
         }
     }
     /** A class scope adds capabilities to keep track of changes in related
      *  class scopes - this allows client to realize whether a class scope
      *  has changed, either directly (because a new member has been added/removed
      *  to this scope) or indirectly (i.e. because a new member has been
      *  added/removed into a supertype scope)
      */
     public static class CompoundScope extends Scope implements ScopeListener {
         public static final Entry[] emptyTable = new Entry[0];
         private List<Scope> subScopes = List.nil();
         private int mark = 0;
         public CompoundScope(Symbol owner) {
             super(null, owner, emptyTable);
         }
         public void addSubScope(Scope that) {
            if (that != null) {
                 subScopes = subScopes.prepend(that);
                 that.addScopeListener(this);
                 mark++;
                 for (ScopeListener sl : listeners) {
                     sl.symbolAdded(null, this); //propagate upwards in case of nested CompoundScopes
                 }
            }
          }
         public void symbolAdded(Symbol sym, Scope s) {
             mark++;
             for (ScopeListener sl : listeners) {
                 sl.symbolAdded(sym, s);
             }
         }
         public void symbolRemoved(Symbol sym, Scope s) {
             mark++;
             for (ScopeListener sl : listeners) {
                 sl.symbolRemoved(sym, s);
             }
         }
         public int getMark() {
             return mark;
         }
         @Override
         public String toString() {
             StringBuilder buf = new StringBuilder();
             buf.append("CompoundScope{");
             String sep = "";
             for (Scope s : subScopes) {
                 buf.append(sep);
                 buf.append(s);
                 sep = ",";
             }
             buf.append("}");
             return buf.toString();
         }
         @Override
         public Iterable<Symbol> getElements(final Filter<Symbol> sf) {
             return new Iterable<Symbol>() {
                 public Iterator<Symbol> iterator() {
                     return new CompoundScopeIterator(subScopes) {
                         Iterator<Symbol> nextIterator(Scope s) {
                             return s.getElements(sf).iterator();
                         }
                     };
                 }
             };
         }
         @Override
         public Iterable<Symbol> getElementsByName(final Name name, final Filter<Symbol> sf) {
             return new Iterable<Symbol>() {
                 public Iterator<Symbol> iterator() {
                     return new CompoundScopeIterator(subScopes) {
                         Iterator<Symbol> nextIterator(Scope s) {
                             return s.getElementsByName(name, sf).iterator();
                         }
                     };
                 }
             };
         }
         abstract class CompoundScopeIterator implements Iterator<Symbol> {
             private Iterator<Symbol> currentIterator;
             private List<Scope> scopesToScan;
             public CompoundScopeIterator(List<Scope> scopesToScan) {
                 this.scopesToScan = scopesToScan;
                 update();
             }
             abstract Iterator<Symbol> nextIterator(Scope s);
             public boolean hasNext() {
                 return currentIterator != null;
             }
             public Symbol next() {
                 Symbol sym = currentIterator.next();
                 if (!currentIterator.hasNext()) {
                     update();
                 }
                 return sym;
             }
             public void remove() {
                 throw new UnsupportedOperationException();
             }
             private void update() {
                 while (scopesToScan.nonEmpty()) {
                     currentIterator = nextIterator(scopesToScan.head);
                     scopesToScan = scopesToScan.tail;
                     if (currentIterator.hasNext()) return;
                 }
                 currentIterator = null;
             }
         }
         @Override
         public Entry lookup(Name name, Filter<Symbol> sf) {
             throw new UnsupportedOperationException();
         }
         @Override
         public Scope dup(Symbol newOwner) {
             throw new UnsupportedOperationException();
         }
         @Override
         public void enter(Symbol sym, Scope s, Scope origin, boolean staticallyImported) {
             throw new UnsupportedOperationException();
         }
         @Override
         public void remove(Symbol sym) {
             throw new UnsupportedOperationException();
         }
     }
     /** An error scope, for which the owner should be an error symbol. */
     public static class ErrorScope extends Scope {
         ErrorScope(Scope next, Symbol errSymbol, Entry[] table) {
             super(next, /*owner=*/errSymbol, table);
         }
         public ErrorScope(Symbol errSymbol) {
             super(errSymbol);
         }
         public Scope dup() {
             return new ErrorScope(this, owner, table);
         }
         public Scope dupUnshared() {
             return new ErrorScope(this, owner, table.clone());
         }
         public Entry lookup(Name name) {
             Entry e = super.lookup(name);
             if (e.scope == null)
                 return new Entry(owner, null, null, null);
             else
                 return e;
         }
     }
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/com/sun/tools/javac/code/Scope.java@ca5783d9a597 (annotated)

src/share/classes/com/sun/tools/javac/code/Scope.java