package dotty.tools.dotc
package core
import scala.io.Codec
import util.NameTransformer
import printing.{Showable, Texts, Printer}
import Texts.Text
import Decorators._
import Contexts.Context
import collection.IndexedSeqOptimized
import collection.generic.CanBuildFrom
import collection.mutable.{ Builder, StringBuilder }
import collection.immutable.WrappedString
import collection.generic.CanBuildFrom
import util.DotClass
//import annotation.volatile
object Names {
/** A common class for things that can be turned into names.
* Instances are both names and strings, the latter via a decorator.
*/
trait PreName extends Any with Showable {
def toTypeName: TypeName
def toTermName: TermName
}
/** A name is essentially a string, with three differences
* 1. Names belong in one of two name spaces: they are type names or term names.
* Term names have a sub-category of "local" field names.
* The same string can correspond a name in each of the three namespaces.
* 2. Names are hash-consed. Two names
* representing the same string in the same universe are always reference identical.
* 3. Names are intended to be encoded strings. @see dotc.util.NameTransformer.
* The encoding will be applied when converting a string to a name.
*/
abstract class Name extends DotClass
with PreName
with Seq[Char]
with IndexedSeqOptimized[Char, Name] {
/** A type for names of the same kind as this name */
type ThisName <: Name
/** The start index in the character array */
val start: Int
/** The length of the names */
override val length: Int
/** Is this name a type name? */
def isTypeName: Boolean
/** Is this name a term name? */
def isTermName: Boolean
/** This name converted to a type name */
def toTypeName: TypeName
/** This name converted to a term name */
def toTermName: TermName
/** This name downcasted to a type name */
def asTypeName: TypeName
/** This name downcasted to a term name */
def asTermName: TermName
/** Create a new name of same kind as this one, in the given
* basis, with `len` characters taken from `cs` starting at `offset`.
*/
def fromChars(cs: Array[Char], offset: Int, len: Int): ThisName
/** Create new name of same kind as this name and with same
* characters as given `name`.
*/
def fromName(name: Name): ThisName = fromChars(chrs, name.start, name.length)
/** Create new name of same kind as this name with characters from
* the given string
*/
def fromString(str: String): ThisName = {
val cs = str.toCharArray
fromChars(cs, 0, cs.length)
}
override def toString =
if (length == 0) "" else new String(chrs, start, length)
def toText(printer: Printer): Text = printer.toText(this)
/** Write to UTF8 representation of this name to given character array.
* Start copying to index `to`. Return index of next free byte in array.
* Array must have enough remaining space for all bytes
* (i.e. maximally 3*length bytes).
*/
final def copyUTF8(bs: Array[Byte], offset: Int): Int = {
val bytes = Codec.toUTF8(chrs, start, length)
scala.compat.Platform.arraycopy(bytes, 0, bs, offset, bytes.length)
offset + bytes.length
}
/** Replace \$op_name's by corresponding operator symbols. */
def decode: Name =
if (contains('$')) fromString(NameTransformer.decode(toString))
else this
/** Replace operator symbols by corresponding \$op_name's. */
def encode: Name =
if (dontEncode(toTermName)) this else NameTransformer.encode(this)
/** A more efficient version of concatenation */
def ++ (other: Name): ThisName = ++ (other.toString)
def ++ (other: String): ThisName = {
val s = toString + other
fromChars(s.toCharArray, 0, s.length)
}
def replace(from: Char, to: Char): ThisName = {
val cs = new Array[Char](length)
Array.copy(chrs, start, cs, 0, length)
for (i <- 0 until length) {
if (cs(i) == from) cs(i) = to
}
fromChars(cs, 0, length)
}
def contains(ch: Char): Boolean = {
var i = 0
while (i < length && chrs(start + i) != ch) i += 1
i < length
}
def firstChar = chrs(start)
// ----- Collections integration -------------------------------------
override protected[this] def thisCollection: WrappedString = new WrappedString(repr.toString)
override protected[this] def toCollection(repr: Name): WrappedString = new WrappedString(repr.toString)
override protected[this] def newBuilder: Builder[Char, Name] = unsupported("newBuilder")
override def apply(index: Int): Char = chrs(start + index)
override def slice(from: Int, until: Int): ThisName =
fromChars(chrs, start + from, until - from)
override def equals(that: Any) = this eq that.asInstanceOf[AnyRef]
override def seq = toCollection(this)
}
class TermName(val start: Int, val length: Int, private[Names] var next: TermName) extends Name {
type ThisName = TermName
def isTypeName = false
def isTermName = true
@volatile private[this] var _typeName: TypeName = null
def toTypeName: TypeName = {
if (_typeName == null)
synchronized {
if (_typeName == null)
_typeName = new TypeName(start, length, this)
}
_typeName
}
def toTermName = this
def asTypeName = throw new ClassCastException(this + " is not a type name")
def asTermName = this
override def hashCode: Int = start
override protected[this] def newBuilder: Builder[Char, Name] = termNameBuilder
def fromChars(cs: Array[Char], offset: Int, len: Int): TermName = termName(cs, offset, len)
}
class TypeName(val start: Int, val length: Int, val toTermName: TermName) extends Name {
type ThisName = TypeName
def isTypeName = true
def isTermName = false
def toTypeName = this
def asTypeName = this
def asTermName = throw new ClassCastException(this + " is not a term name")
override def hashCode: Int = -start
override protected[this] def newBuilder: Builder[Char, Name] =
termNameBuilder.mapResult(_.toTypeName)
def fromChars(cs: Array[Char], offset: Int, len: Int): TypeName = typeName(cs, offset, len)
}
// Nametable
private final val InitialHashSize = 0x8000
private final val InitialNameSize = 0x20000
private final val fillFactor = 0.7
/** Memory to store all names sequentially. */
private var chrs: Array[Char] = new Array[Char](InitialNameSize)
/** The number of characters filled. */
private var nc = 0
/** Hashtable for finding term names quickly. */
private var table = new Array[TermName](InitialHashSize)
/** The number of defined names. */
private var size = 1
/** Make sure the capacity of the character array is at least `n` */
private def ensureCapacity(n: Int) =
if (n > chrs.length) {
val newchrs = new Array[Char](chrs.length * 2)
chrs.copyToArray(newchrs)
chrs = newchrs
}
/** Make sure the hash table is large enough for the given load factor */
private def incTableSize() = {
size += 1
if (size.toDouble / table.size > fillFactor) {
val oldTable = table
table = new Array[TermName](table.size * 2)
for (i <- 0 until oldTable.size) rehash(oldTable(i))
}
}
/** Rehash chain of names */
private def rehash(name: TermName): Unit =
if (name != null) {
rehash(name.next)
val h = hashValue(chrs, name.start, name.length) & (table.size - 1)
name.next = table(h)
table(h) = name
}
/** The hash of a name made of from characters cs[offset..offset+len-1]. */
private def hashValue(cs: Array[Char], offset: Int, len: Int): Int =
if (len > 0)
(len * (41 * 41 * 41) +
cs(offset) * (41 * 41) +
cs(offset + len - 1) * 41 +
cs(offset + (len >> 1)))
else 0
/** Is (the ASCII representation of) name at given index equal to
* cs[offset..offset+len-1]?
*/
private def equals(index: Int, cs: Array[Char], offset: Int, len: Int): Boolean = {
var i = 0
while ((i < len) && (chrs(index + i) == cs(offset + i)))
i += 1
i == len
}
/** Enter characters into chrs array. */
private def enterChars(cs: Array[Char], offset: Int, len: Int): Unit = {
ensureCapacity(nc + len)
var i = 0
while (i < len) {
chrs(nc + i) = cs(offset + i)
i += 1
}
nc += len
}
/** Create a term name from the characters in cs[offset..offset+len-1].
* Assume they are already encoded.
*/
def termName(cs: Array[Char], offset: Int, len: Int): TermName = {
util.Stats.record("termName")
val h = hashValue(cs, offset, len) & (table.size - 1)
synchronized {
val next = table(h)
var name = next
while (name ne null) {
if (name.length == len && equals(name.start, cs, offset, len))
return name
name = name.next
}
name = new TermName(nc, len, next)
enterChars(cs, offset, len)
table(h) = name
incTableSize()
name
}
}
/** Create a type name from the characters in cs[offset..offset+len-1].
* Assume they are already encoded.
*/
def typeName(cs: Array[Char], offset: Int, len: Int): TypeName =
termName(cs, offset, len).toTypeName
/** Create a term name from the UTF8 encoded bytes in bs[offset..offset+len-1].
* Assume they are already encoded.
*/
def termName(bs: Array[Byte], offset: Int, len: Int): TermName = {
val chars = Codec.fromUTF8(bs, offset, len)
termName(chars, 0, chars.length)
}
/** Create a type name from the UTF8 encoded bytes in bs[offset..offset+len-1].
* Assume they are already encoded.
*/
def typeName(bs: Array[Byte], offset: Int, len: Int): TypeName =
termName(bs, offset, len).toTypeName
/** Create a term name from a string, without encoding operators */
def termName(s: String): TermName = termName(s.toCharArray, 0, s.length)
/** Create a type name from a string, wihtout encoding operators */
def typeName(s: String): TypeName = typeName(s.toCharArray, 0, s.length)
/** The term name represented by the empoty string */
val EmptyTermName = new TermName(-1, 0, null)
table(0) = EmptyTermName
/** The type name represented by the empoty string */
val EmptyTypeName = EmptyTermName.toTypeName
// can't move CONSTRUCTOR/EMPTY_PACKAGE to `nme` because of bootstrap failures in `encode`.
val CONSTRUCTOR = termName("<init>")
val EMPTY_PACKAGE = termName("<empty>")
val dontEncode = Set(CONSTRUCTOR, EMPTY_PACKAGE)
def termNameBuilder: Builder[Char, TermName] =
StringBuilder.newBuilder.mapResult(termName)
implicit val nameCanBuildFrom: CanBuildFrom[Name, Char, Name] = new CanBuildFrom[Name, Char, Name] {
def apply(from: Name): Builder[Char, Name] =
StringBuilder.newBuilder.mapResult(s => from.fromChars(s.toCharArray, 0, s.length))
def apply(): Builder[Char, Name] = termNameBuilder
}
}
