diff options
Diffstat (limited to 'src/reflect/scala/reflect/internal/Scopes.scala')
| -rw-r--r-- | src/reflect/scala/reflect/internal/Scopes.scala | 176 |
1 files changed, 120 insertions, 56 deletions
diff --git a/src/reflect/scala/reflect/internal/Scopes.scala b/src/reflect/scala/reflect/internal/Scopes.scala index ab3b9b7ed7..8d20c8e546 100644 --- a/src/reflect/scala/reflect/internal/Scopes.scala +++ b/src/reflect/scala/reflect/internal/Scopes.scala @@ -3,11 +3,22 @@ * @author Martin Odersky */ -package scala.reflect +package scala +package reflect package internal +import scala.annotation.tailrec + trait Scopes extends api.Scopes { self: SymbolTable => + /** An ADT to represent the results of symbol name lookups. + */ + sealed trait NameLookup { def symbol: Symbol ; def isSuccess = false } + case class LookupSucceeded(qualifier: Tree, symbol: Symbol) extends NameLookup { override def isSuccess = true } + case class LookupAmbiguous(msg: String) extends NameLookup { def symbol = NoSymbol } + case class LookupInaccessible(symbol: Symbol, msg: String) extends NameLookup + case object LookupNotFound extends NameLookup { def symbol = NoSymbol } + class ScopeEntry(val sym: Symbol, val owner: Scope) { /** the next entry in the hash bucket */ @@ -17,15 +28,11 @@ trait Scopes extends api.Scopes { self: SymbolTable => */ var next: ScopeEntry = null + def depth = owner.nestingLevel override def hashCode(): Int = sym.name.start - override def toString(): String = sym.toString() + override def toString() = s"$sym (depth=$depth)" } - /** - * @param sym ... - * @param owner ... - * @return ... - */ private def newScopeEntry(sym: Symbol, owner: Scope): ScopeEntry = { val e = new ScopeEntry(sym, owner) e.next = owner.elems @@ -61,6 +68,11 @@ trait Scopes extends api.Scopes { self: SymbolTable => /** a cache for all elements, to be used by symbol iterator. */ private var elemsCache: List[Symbol] = null + private var cachedSize = -1 + private def flushElemsCache() { + elemsCache = null + cachedSize = -1 + } /** size and mask of hash tables * todo: make hashtables grow? @@ -82,6 +94,12 @@ trait Scopes extends api.Scopes { self: SymbolTable => /** the number of entries in this scope */ override def size: Int = { + if (cachedSize < 0) + cachedSize = directSize + + cachedSize + } + private def directSize: Int = { var s = 0 var e = elems while (e ne null) { @@ -92,11 +110,9 @@ trait Scopes extends api.Scopes { self: SymbolTable => } /** enter a scope entry - * - * @param e ... */ protected def enterEntry(e: ScopeEntry) { - elemsCache = null + flushElemsCache() if (hashtable ne null) enterInHash(e) else if (size >= MIN_HASH) @@ -110,8 +126,6 @@ trait Scopes extends api.Scopes { self: SymbolTable => } /** enter a symbol - * - * @param sym ... */ def enter[T <: Symbol](sym: T): T = { enterEntry(newScopeEntry(sym, this)) @@ -119,8 +133,6 @@ trait Scopes extends api.Scopes { self: SymbolTable => } /** enter a symbol, asserting that no symbol with same name exists in scope - * - * @param sym ... */ def enterUnique(sym: Symbol) { assert(lookup(sym.name) == NoSymbol, (sym.fullLocationString, lookup(sym.name).fullLocationString)) @@ -175,8 +187,6 @@ trait Scopes extends api.Scopes { self: SymbolTable => } /** remove entry - * - * @param e ... */ def unlink(e: ScopeEntry) { if (elems == e) { @@ -192,30 +202,64 @@ trait Scopes extends api.Scopes { self: SymbolTable => if (e1 == e) { hashtable(index) = e.tail } else { - while (e1.tail != e) e1 = e1.tail; + while (e1.tail != e) e1 = e1.tail e1.tail = e.tail } } - elemsCache = null + flushElemsCache() } /** remove symbol */ def unlink(sym: Symbol) { var e = lookupEntry(sym.name) while (e ne null) { - if (e.sym == sym) unlink(e); + if (e.sym == sym) unlink(e) e = lookupNextEntry(e) } } - /** lookup a symbol - * - * @param name ... - * @return ... + /** Lookup a module or a class, filtering out matching names in scope + * which do not match that requirement. + */ + def lookupModule(name: Name): Symbol = lookupAll(name.toTermName) find (_.isModule) getOrElse NoSymbol + def lookupClass(name: Name): Symbol = lookupAll(name.toTypeName) find (_.isClass) getOrElse NoSymbol + + /** True if the name exists in this scope, false otherwise. */ + def containsName(name: Name) = lookupEntry(name) != null + + /** Lookup a symbol. */ def lookup(name: Name): Symbol = { val e = lookupEntry(name) - if (e eq null) NoSymbol else e.sym + if (e eq null) NoSymbol + else if (lookupNextEntry(e) eq null) e.sym + else { + // We shouldn't get here: until now this method was picking a random + // symbol when there was more than one with the name, so this should + // only be called knowing that there are 0-1 symbols of interest. So, we + // can safely return an overloaded symbol rather than throwing away the + // rest of them. Most likely we still break, but at least we will break + // in an understandable fashion (unexpectedly overloaded symbol) rather + // than a non-deterministic bizarre one (see any bug involving overloads + // in package objects.) + val alts = lookupAll(name).toList + def alts_s = alts map (s => s.defString) mkString " <and> " + devWarning(s"scope lookup of $name found multiple symbols: $alts_s") + // FIXME - how is one supposed to create an overloaded symbol without + // knowing the correct owner? Using the symbol owner is not correct; + // say for instance this is List's scope and the symbols are its three + // mkString members. Those symbols are owned by TraversableLike, which + // is no more meaningful an owner than NoSymbol given that we're in + // List. Maybe it makes no difference who owns the overloaded symbol, in + // which case let's establish that and have a canonical creation method. + // + // FIXME - a similar question for prefix, although there are more + // clues from the symbols on that one, as implemented here. In general + // the distinct list is one type and lub becomes the identity. + // val prefix = lub(alts map (_.info.prefix) distinct) + // Now using NoSymbol and NoPrefix always to avoid forcing info (SI-6664) + NoSymbol.newOverloaded(NoPrefix, alts) + } } /** Returns an iterator yielding every symbol with given name in this scope. @@ -223,7 +267,20 @@ trait Scopes extends api.Scopes { self: SymbolTable => def lookupAll(name: Name): Iterator[Symbol] = new Iterator[Symbol] { var e = lookupEntry(name) def hasNext: Boolean = e ne null - def next(): Symbol = { val r = e.sym; e = lookupNextEntry(e); r } + def next(): Symbol = try e.sym finally e = lookupNextEntry(e) + } + + def lookupAllEntries(name: Name): Iterator[ScopeEntry] = new Iterator[ScopeEntry] { + var e = lookupEntry(name) + def hasNext: Boolean = e ne null + def next(): ScopeEntry = try e finally e = lookupNextEntry(e) + } + + def lookupUnshadowedEntries(name: Name): Iterator[ScopeEntry] = { + lookupEntry(name) match { + case null => Iterator.empty + case e => lookupAllEntries(name) filter (e1 => (e eq e1) || (e.depth == e1.depth && e.sym != e1.sym)) + } } /** lookup a symbol entry matching given name. @@ -257,20 +314,47 @@ trait Scopes extends api.Scopes { self: SymbolTable => if (hashtable ne null) do { e = e.tail } while ((e ne null) && e.sym.name != entry.sym.name) else - do { e = e.next } while ((e ne null) && e.sym.name != entry.sym.name); + do { e = e.next } while ((e ne null) && e.sym.name != entry.sym.name) e } + /** TODO - we can test this more efficiently than checking isSubScope + * in both directions. However the size test might be enough to quickly + * rule out most failures. + */ + def isSameScope(other: Scope) = ( + (size == other.size) // optimization - size is cached + && (this isSubScope other) + && (other isSubScope this) + ) + + def isSubScope(other: Scope) = { + def scopeContainsSym(sym: Symbol): Boolean = { + @tailrec def entryContainsSym(e: ScopeEntry): Boolean = e match { + case null => false + case _ => + val comparableInfo = sym.info.substThis(sym.owner, e.sym.owner) + (e.sym.info =:= comparableInfo) || entryContainsSym(lookupNextEntry(e)) + } + entryContainsSym(this lookupEntry sym.name) + } + other.toList forall scopeContainsSym + } + /** Return all symbols as a list in the order they were entered in this scope. */ override def toList: List[Symbol] = { if (elemsCache eq null) { - elemsCache = Nil + var symbols: List[Symbol] = Nil + var count = 0 var e = elems while ((e ne null) && e.owner == this) { - elemsCache = e.sym :: elemsCache + count += 1 + symbols ::= e.sym e = e.next } + elemsCache = symbols + cachedSize = count } elemsCache } @@ -287,36 +371,16 @@ trait Scopes extends api.Scopes { self: SymbolTable => */ def iterator: Iterator[Symbol] = toList.iterator -/* - /** Does this scope contain an entry for `sym`? - */ - def contains(sym: Symbol): Boolean = lookupAll(sym.name) contains sym - - /** A scope that contains all symbols of this scope and that also contains `sym`. - */ - def +(sym: Symbol): Scope = - if (contains(sym)) this - else { - val result = cloneScope - result enter sym - result - } - - /** A scope that contains all symbols of this scope except `sym`. - */ - def -(sym: Symbol): Scope = - if (!contains(sym)) this - else { - val result = cloneScope - result unlink sym - result - } -*/ override def foreach[U](p: Symbol => U): Unit = toList foreach p - override def filter(p: Symbol => Boolean): Scope = - if (!(toList forall p)) newScopeWith(toList filter p: _*) else this - + override def filterNot(p: Symbol => Boolean): Scope = ( + if (toList exists p) newScopeWith(toList filterNot p: _*) + else this + ) + override def filter(p: Symbol => Boolean): Scope = ( + if (toList forall p) this + else newScopeWith(toList filter p: _*) + ) @deprecated("Use `toList.reverse` instead", "2.10.0") def reverse: List[Symbol] = toList.reverse |