scala.reflect.internal.Scopes.scala Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of scala-reflect Show documentation
Show all versions of scala-reflect Show documentation
Compiler for the Scala Programming Language
/* NSC -- new Scala compiler
* Copyright 2005-2012 LAMP/EPFL
* @author Martin Odersky
*/
package scala.reflect
package internal
trait Scopes extends api.Scopes { self: SymbolTable =>
class ScopeEntry(val sym: Symbol, val owner: Scope) {
/** the next entry in the hash bucket
*/
var tail: ScopeEntry = null
/** the next entry in this scope
*/
var next: ScopeEntry = null
override def hashCode(): Int = sym.name.start
override def toString(): String = sym.toString()
}
/**
* @param sym ...
* @param owner ...
* @return ...
*/
private def newScopeEntry(sym: Symbol, owner: Scope): ScopeEntry = {
val e = new ScopeEntry(sym, owner)
e.next = owner.elems
owner.elems = e
e
}
object Scope {
def unapplySeq(decls: Scope): Some[Seq[Symbol]] = Some(decls.toList)
}
/** Note: constructor is protected to force everyone to use the factory methods newScope or newNestedScope instead.
* This is necessary because when run from reflection every scope needs to have a
* SynchronizedScope as mixin.
*/
class Scope protected[Scopes] (initElems: ScopeEntry = null, initFingerPrints: Long = 0L) extends ScopeBase with MemberScopeBase {
protected[Scopes] def this(base: Scope) = {
this(base.elems)
nestinglevel = base.nestinglevel + 1
}
private[scala] var elems: ScopeEntry = initElems
/** The number of times this scope is nested in another
*/
private var nestinglevel = 0
/** the hash table
*/
private var hashtable: Array[ScopeEntry] = null
/** a cache for all elements, to be used by symbol iterator.
*/
private var elemsCache: List[Symbol] = null
/** size and mask of hash tables
* todo: make hashtables grow?
*/
private val HASHSIZE = 0x80
private val HASHMASK = 0x7f
/** the threshold number of entries from which a hashtable is constructed.
*/
private val MIN_HASH = 8
if (size >= MIN_HASH) createHash()
/** Returns a new scope with the same content as this one. */
def cloneScope: Scope = newScopeWith(this.toList: _*)
/** is the scope empty? */
override def isEmpty: Boolean = elems eq null
/** the number of entries in this scope */
override def size: Int = {
var s = 0
var e = elems
while (e ne null) {
s += 1
e = e.next
}
s
}
/** enter a scope entry
*
* @param e ...
*/
protected def enterEntry(e: ScopeEntry) {
elemsCache = null
if (hashtable ne null)
enterInHash(e)
else if (size >= MIN_HASH)
createHash()
}
private def enterInHash(e: ScopeEntry): Unit = {
val i = e.sym.name.start & HASHMASK
e.tail = hashtable(i)
hashtable(i) = e
}
/** enter a symbol
*
* @param sym ...
*/
def enter[T <: Symbol](sym: T): T = {
enterEntry(newScopeEntry(sym, this))
sym
}
/** 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))
enter(sym)
}
private def createHash() {
hashtable = new Array[ScopeEntry](HASHSIZE)
enterAllInHash(elems)
}
private def enterAllInHash(e: ScopeEntry, n: Int = 0) {
if (e ne null) {
if (n < maxRecursions) {
enterAllInHash(e.next, n + 1)
enterInHash(e)
} else {
var entries: List[ScopeEntry] = List()
var ee = e
while (ee ne null) {
entries = ee :: entries
ee = ee.next
}
entries foreach enterInHash
}
}
}
def rehash(sym: Symbol, newname: Name) {
if (hashtable ne null) {
val index = sym.name.start & HASHMASK
var e1 = hashtable(index)
var e: ScopeEntry = null
if (e1 != null) {
if (e1.sym == sym) {
hashtable(index) = e1.tail
e = e1
} else {
while (e1.tail != null && e1.tail.sym != sym) e1 = e1.tail
if (e1.tail != null) {
e = e1.tail
e1.tail = e.tail
}
}
}
if (e != null) {
val newindex = newname.start & HASHMASK
e.tail = hashtable(newindex)
hashtable(newindex) = e
}
}
}
/** remove entry
*
* @param e ...
*/
def unlink(e: ScopeEntry) {
if (elems == e) {
elems = e.next
} else {
var e1 = elems
while (e1.next != e) e1 = e1.next
e1.next = e.next
}
if (hashtable ne null) {
val index = e.sym.name.start & HASHMASK
var e1 = hashtable(index)
if (e1 == e) {
hashtable(index) = e.tail
} else {
while (e1.tail != e) e1 = e1.tail;
e1.tail = e.tail
}
}
elemsCache = null
}
/** remove symbol */
def unlink(sym: Symbol) {
var e = lookupEntry(sym.name)
while (e ne null) {
if (e.sym == sym) unlink(e);
e = lookupNextEntry(e)
}
}
/** lookup a symbol
*
* @param name ...
* @return ...
*/
def lookup(name: Name): Symbol = {
val e = lookupEntry(name)
if (e eq null) NoSymbol else e.sym
}
/** Returns an iterator yielding every symbol with given name in this scope.
*/
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 }
}
/** lookup a symbol entry matching given name.
* @note from Martin: I believe this is a hotspot or will be one
* in future versions of the type system. I have reverted the previous
* change to use iterators as too costly.
*/
def lookupEntry(name: Name): ScopeEntry = {
var e: ScopeEntry = null
if (hashtable ne null) {
e = hashtable(name.start & HASHMASK)
while ((e ne null) && e.sym.name != name) {
e = e.tail
}
} else {
e = elems
while ((e ne null) && e.sym.name != name) {
e = e.next
}
}
e
}
/** lookup next entry with same name as this one
* @note from Martin: I believe this is a hotspot or will be one
* in future versions of the type system. I have reverted the previous
* change to use iterators as too costly.
*/
def lookupNextEntry(entry: ScopeEntry): ScopeEntry = {
var e = entry
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);
e
}
/** 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 e = elems
while ((e ne null) && e.owner == this) {
elemsCache = e.sym :: elemsCache
e = e.next
}
}
elemsCache
}
/** Vanilla scope - symbols are stored in declaration order.
*/
def sorted: List[Symbol] = toList
/** Return the nesting level of this scope, i.e. the number of times this scope
* was nested in another */
def nestingLevel = nestinglevel
/** Return all symbols as an iterator in the order they were entered in this scope.
*/
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
@deprecated("Use `toList.reverse` instead", "2.10.0")
def reverse: List[Symbol] = toList.reverse
override def mkString(start: String, sep: String, end: String) =
toList.map(_.defString).mkString(start, sep, end)
override def toString(): String = mkString("Scope{\n ", ";\n ", "\n}")
}
implicit val ScopeTag = ClassTag[Scope](classOf[Scope])
type MemberScope = Scope
implicit val MemberScopeTag = ClassTag[MemberScope](classOf[MemberScope])
/** Create a new scope */
def newScope: Scope = new Scope()
/** Create a new scope to be used in `findMembers`.
*
* But why do we need a special scope for `findMembers`?
* Let me tell you a story.
*
* `findMembers` creates a synthetic scope and then iterates over
* base classes in linearization order, and for every scrutinized class
* iterates over `decls`, the collection of symbols declared in that class.
* Declarations that fit the filter get appended to the created scope.
*
* The problem is that `decls` returns a Scope, and to iterate a scope performantly
* one needs to go from its end to its beginning.
*
* Hence the `findMembers` scope is populated in a wicked order:
* symbols that belong to the same declaring class come in reverse order of their declaration,
* however, the scope itself is ordered w.r.t the linearization of the target type.
*
* Once `members` became a public API, this has been confusing countless numbers of users.
* Therefore we introduce a special flavor of scopes to accommodate this quirk of `findMembers`
*/
private[scala] def newFindMemberScope: Scope = new Scope() {
override def sorted = {
val members = toList
val owners = members.map(_.owner).distinct
val grouped = members groupBy (_.owner)
owners.flatMap(owner => grouped(owner).reverse)
}
}
/** Create a new scope nested in another one with which it shares its elements */
def newNestedScope(outer: Scope): Scope = new Scope(outer)
/** Create a new scope with given initial elements */
def newScopeWith(elems: Symbol*): Scope = {
val scope = newScope
elems foreach scope.enter
scope
}
/** Create new scope for the members of package `pkg` */
def newPackageScope(pkgClass: Symbol): Scope = newScope
/** Transform scope of members of `owner` using operation `op`
* This is overridden by the reflective compiler to avoid creating new scopes for packages
*/
def scopeTransform(owner: Symbol)(op: => Scope): Scope = op
/** The empty scope (immutable).
*/
object EmptyScope extends Scope {
override def enterEntry(e: ScopeEntry) {
abort("EmptyScope.enter")
}
}
/** The error scope.
*/
class ErrorScope(owner: Symbol) extends Scope
private final val maxRecursions = 1000
}