| /* |
| * 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; |
| } |
| } |
| } |