Scala example source code file (Names.scala)
The Names.scala Scala example source code/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Martin Odersky
*/
package scala
package reflect
package internal
import scala.io.Codec
import java.security.MessageDigest
import scala.language.implicitConversions
trait Names extends api.Names {
private final val HASH_SIZE = 0x8000
private final val HASH_MASK = 0x7FFF
private final val NAME_SIZE = 0x20000
final val nameDebug = false
// Ideally we would just synchronize unconditionally and let HotSpot's Biased Locking
// kick in in the compiler universe, where access to the lock is single threaded. But,
// objects created in the first 4seconds of the JVM startup aren't eligible for biased
// locking.
//
// We might also be able to accept the performance hit, but we don't have tools to
// detect performance regressions.
//
// Discussion: https://groups.google.com/forum/#!search/biased$20scala-internals/scala-internals/0cYB7SkJ-nM/47MLhsgw8jwJ
protected def synchronizeNames: Boolean = false
private val nameLock: Object = new Object
/** Memory to store all names sequentially. */
var chrs: Array[Char] = new Array[Char](NAME_SIZE)
private var nc = 0
/** Hashtable for finding term names quickly. */
private val termHashtable = new Array[TermName](HASH_SIZE)
/** Hashtable for finding type names quickly. */
private val typeHashtable = new Array[TypeName](HASH_SIZE)
/** The hashcode of a name. */
private def hashValue(cs: Array[Char], offset: Int, len: Int): Int =
if (len > 0)
(len * (41 * 41 * 41) +
cs(offset) * (41 * 41) +
cs(offset + len - 1) * 41 +
cs(offset + (len >> 1)))
else 0
/** Is (the ASCII representation of) name at given index equal to
* cs[offset..offset+len-1]?
*/
private def equals(index: Int, cs: Array[Char], offset: Int, len: Int): Boolean = {
var i = 0
while ((i < len) && (chrs(index + i) == cs(offset + i)))
i += 1
i == len
}
/** Enter characters into chrs array. */
private def enterChars(cs: Array[Char], offset: Int, len: Int) {
var i = 0
while (i < len) {
if (nc + i == chrs.length) {
val newchrs = new Array[Char](chrs.length * 2)
scala.compat.Platform.arraycopy(chrs, 0, newchrs, 0, chrs.length)
chrs = newchrs
}
chrs(nc + i) = cs(offset + i)
i += 1
}
if (len == 0) nc += 1
else nc = nc + len
}
/** Create a term name from the characters in cs[offset..offset+len-1]. */
final def newTermName(cs: Array[Char], offset: Int, len: Int): TermName =
newTermName(cs, offset, len, cachedString = null)
final def newTermName(cs: Array[Char]): TermName = newTermName(cs, 0, cs.length)
final def newTypeName(cs: Array[Char]): TypeName = newTypeName(cs, 0, cs.length)
/** Create a term name from the characters in cs[offset..offset+len-1].
* TODO - have a mode where name validation is performed at creation time
* (e.g. if a name has the string "$class" in it, then fail if that
* string is not at the very end.)
*
* @param len0 the length of the name. Negative lengths result in empty names.
*/
final def newTermName(cs: Array[Char], offset: Int, len0: Int, cachedString: String): TermName = {
def body = {
require(offset >= 0, "offset must be non-negative, got " + offset)
val len = math.max(len0, 0)
val h = hashValue(cs, offset, len) & HASH_MASK
var n = termHashtable(h)
while ((n ne null) && (n.length != len || !equals(n.start, cs, offset, len)))
n = n.next
if (n ne null) n
else {
// The logic order here is future-proofing against the possibility
// that name.toString will become an eager val, in which case the call
// to enterChars cannot follow the construction of the TermName.
val ncStart = nc
enterChars(cs, offset, len)
if (cachedString ne null) new TermName_S(ncStart, len, h, cachedString)
else new TermName_R(ncStart, len, h)
}
}
if (synchronizeNames) nameLock.synchronized(body) else body
}
final def newTypeName(cs: Array[Char], offset: Int, len: Int, cachedString: String): TypeName =
newTermName(cs, offset, len, cachedString).toTypeName
/** Create a term name from string. */
@deprecatedOverriding("To synchronize, use `override def synchronizeNames = true`", "2.11.0") // overriden in https://github.com/scala-ide/scala-ide/blob/master/org.scala-ide.sdt.core/src/scala/tools/eclipse/ScalaPresentationCompiler.scala
def newTermName(s: String): TermName = newTermName(s.toCharArray(), 0, s.length(), null)
/** Create a type name from string. */
@deprecatedOverriding("To synchronize, use `override def synchronizeNames = true`", "2.11.0") // overriden in https://github.com/scala-ide/scala-ide/blob/master/org.scala-ide.sdt.core/src/scala/tools/eclipse/ScalaPresentationCompiler.scala
def newTypeName(s: String): TypeName = newTermName(s).toTypeName
/** Create a term name from the UTF8 encoded bytes in bs[offset..offset+len-1]. */
final def newTermName(bs: Array[Byte], offset: Int, len: Int): TermName = {
val chars = Codec.fromUTF8(bs, offset, len)
newTermName(chars, 0, chars.length)
}
final def newTermNameCached(s: String): TermName =
newTermName(s.toCharArray(), 0, s.length(), cachedString = s)
final def newTypeNameCached(s: String): TypeName =
newTypeName(s.toCharArray(), 0, s.length(), cachedString = s)
/** Create a type name from the characters in cs[offset..offset+len-1]. */
final def newTypeName(cs: Array[Char], offset: Int, len: Int): TypeName =
newTermName(cs, offset, len, cachedString = null).toTypeName
/** Create a type name from the UTF8 encoded bytes in bs[offset..offset+len-1]. */
final def newTypeName(bs: Array[Byte], offset: Int, len: Int): TypeName =
newTermName(bs, offset, len).toTypeName
/**
* Used only by the GenBCode backend, to represent bytecode-level types in a way that makes equals() and hashCode() efficient.
* For bytecode-level types of OBJECT sort, its internal name (not its descriptor) is stored.
* For those of ARRAY sort, its descriptor is stored ie has a leading '['
* For those of METHOD sort, its descriptor is stored ie has a leading '('
*
* can-multi-thread
* TODO SI-6240 !!! JZ Really? the constructors TermName and TypeName publish unconstructed `this` references
* into the hash tables; we could observe them here before the subclass constructor completes.
*/
final def lookupTypeName(cs: Array[Char]): TypeName = { lookupTypeNameIfExisting(cs, true) }
final def lookupTypeNameIfExisting(cs: Array[Char], failOnNotFound: Boolean): TypeName = {
val hterm = hashValue(cs, 0, cs.size) & HASH_MASK
var nterm = termHashtable(hterm)
while ((nterm ne null) && (nterm.length != cs.size || !equals(nterm.start, cs, 0, cs.size))) {
nterm = nterm.next
}
if (nterm eq null) {
if (failOnNotFound) { assert(false, "TermName not yet created: " + new String(cs)) }
return null
}
val htype = hashValue(chrs, nterm.start, nterm.length) & HASH_MASK
var ntype = typeHashtable(htype)
while ((ntype ne null) && ntype.start != nterm.start) {
ntype = ntype.next
}
if (ntype eq null) {
if (failOnNotFound) { assert(false, "TypeName not yet created: " + new String(cs)) }
return null
}
ntype
}
// Classes ----------------------------------------------------------------------
/** The name class.
* TODO - resolve schizophrenia regarding whether to treat Names as Strings
* or Strings as Names. Give names the key functions the absence of which
* make people want Strings all the time.
*/
sealed abstract class Name(protected val index: Int, protected val len: Int) extends NameApi {
type ThisNameType >: Null <: Name
protected[this] def thisName: ThisNameType
// Note that "Name with ThisNameType" should be redundant
// because ThisNameType <: Name, but due to SI-6161 the
// compile loses track of this fact.
/** Index into name table */
def start: Int = index
/** The next name in the same hash bucket. */
def next: Name with ThisNameType
/** The length of this name. */
final def length: Int = len
final def isEmpty = length == 0
final def nonEmpty = !isEmpty
def nameKind: String
def isTermName: Boolean
def isTypeName: Boolean
def toTermName: TermName
def toTypeName: TypeName
def companionName: Name
def bothNames: List[Name] = List(toTermName, toTypeName)
/** Return the subname with characters from from to to-1. */
def subName(from: Int, to: Int): Name with ThisNameType
/** Return a new name of the same variety. */
def newName(str: String): Name with ThisNameType
/** Return a new name based on string transformation. */
def mapName(f: String => String): Name with ThisNameType = newName(f(toString))
/** Copy bytes of this name to buffer cs, starting at position `offset`. */
final def copyChars(cs: Array[Char], offset: Int) =
scala.compat.Platform.arraycopy(chrs, index, cs, offset, len)
/** @return the ascii representation of this name */
final def toChars: Array[Char] = { // used by ide
val cs = new Array[Char](len)
copyChars(cs, 0)
cs
}
/** @return the hash value of this name */
final override def hashCode(): Int = index
/** @return true if the string value of this name is equal
* to the string value of the given name or String.
*/
def string_==(that: Name): Boolean = (that ne null) && (toString == that.toString)
def string_==(that: String): Boolean = (that ne null) && (toString == that)
/****
* This has been quite useful to find places where people are comparing
* a TermName and a TypeName, or a Name and a String.
override def equals(other: Any) = paranoidEquals(other)
private def paranoidEquals(other: Any): Boolean = {
val cmp = this eq other.asInstanceOf[AnyRef]
if (cmp || !nameDebug)
return cmp
other match {
case x: String =>
Console.println(s"Compared $debugString and String '$x'")
case x: Name =>
if (this.isTermName != x.isTermName) {
val panic = this.toTermName == x.toTermName
Console.println("Compared '%s' and '%s', one term, one type.%s".format(this, x,
if (panic) " And they contain the same name string!"
else ""
))
}
case _ =>
}
false
}
****/
/** @return the i'th Char of this name */
final def charAt(i: Int): Char = chrs(index + i)
/** @return the index of first occurrence of char c in this name, length if not found */
final def pos(c: Char): Int = pos(c, 0)
/** @return the index of first occurrence of s in this name, length if not found */
final def pos(s: String): Int = pos(s, 0)
/** Returns the index of the first occurrence of character c in
* this name from start, length if not found.
*
* @param c the character
* @param start the index from which to search
* @return the index of the first occurrence of c
*/
final def pos(c: Char, start: Int): Int = {
var i = start
while (i < len && chrs(index + i) != c) i += 1
i
}
/** Returns the index of the first occurrence of nonempty string s
* in this name from start, length if not found.
*
* @param s the string
* @param start the index from which to search
* @return the index of the first occurrence of s
*/
final def pos(s: String, start: Int): Int = {
var i = pos(s.charAt(0), start)
while (i + s.length() <= len) {
var j = 1
while (s.charAt(j) == chrs(index + i + j)) {
j += 1
if (j == s.length()) return i
}
i = pos(s.charAt(0), i + 1)
}
len
}
/** Returns the index of last occurrence of char c in this
* name, -1 if not found.
*
* @param c the character
* @return the index of the last occurrence of c
*/
final def lastPos(c: Char): Int = lastPos(c, len - 1)
/** Returns the index of the last occurrence of char c in this
* name from start, -1 if not found.
*
* @param c the character
* @param start the index from which to search
* @return the index of the last occurrence of c
*/
final def lastPos(c: Char, start: Int): Int = {
var i = start
while (i >= 0 && chrs(index + i) != c) i -= 1
i
}
/** Does this name start with prefix? */
final def startsWith(prefix: Name): Boolean = startsWith(prefix, 0)
/** Does this name start with prefix at given start index? */
final def startsWith(prefix: Name, start: Int): Boolean = {
var i = 0
while (i < prefix.length && start + i < len &&
chrs(index + start + i) == chrs(prefix.start + i))
i += 1
i == prefix.length
}
final def startsWith(prefix: String, start: Int): Boolean = {
var i = 0
while (i < prefix.length && start + i < len &&
chrs(index + start + i) == prefix.charAt(i))
i += 1
i == prefix.length
}
/** Does this name end with suffix? */
final def endsWith(suffix: Name): Boolean = endsWith(suffix, len)
/** Does this name end with suffix just before given end index? */
final def endsWith(suffix: Name, end: Int): Boolean = {
var i = 1
while (i <= suffix.length && i <= end &&
chrs(index + end - i) == chrs(suffix.start + suffix.length - i))
i += 1
i > suffix.length
}
final def endsWith(suffix: String, end: Int): Boolean = {
var i = 1
while (i <= suffix.length && i <= end &&
chrs(index + end - i) == suffix.charAt(suffix.length - i))
i += 1
i > suffix.length
}
final def containsName(subname: String): Boolean = containsName(newTermName(subname))
final def containsName(subname: Name): Boolean = {
var start = 0
val last = len - subname.length
while (start <= last && !startsWith(subname, start)) start += 1
start <= last
}
final def containsChar(ch: Char): Boolean = {
var i = index
val max = index + len
while (i < max) {
if (chrs(i) == ch)
return true
i += 1
}
false
}
/** Some thoroughly self-explanatory convenience functions. They
* assume that what they're being asked to do is known to be valid.
*/
final def startChar: Char = this charAt 0
final def endChar: Char = this charAt len - 1
final def startsWith(char: Char): Boolean = len > 0 && startChar == char
final def startsWith(name: String): Boolean = startsWith(name, 0)
final def endsWith(char: Char): Boolean = len > 0 && endChar == char
final def endsWith(name: String): Boolean = endsWith(name, len)
/** Rewrite the confusing failure indication via result == length to
* the normal failure indication via result == -1.
*/
private def fixIndexOf(idx: Int): Int = if (idx == length) -1 else idx
def indexOf(ch: Char) = fixIndexOf(pos(ch))
def indexOf(ch: Char, fromIndex: Int) = fixIndexOf(pos(ch, fromIndex))
def indexOf(s: String) = fixIndexOf(pos(s))
/** The lastPos methods already return -1 on failure. */
def lastIndexOf(ch: Char): Int = lastPos(ch)
def lastIndexOf(s: String): Int = toString lastIndexOf s
/** Replace all occurrences of `from` by `to` in
* name; result is always a term name.
*/
def replace(from: Char, to: Char): Name = {
val cs = new Array[Char](len)
var i = 0
while (i < len) {
val ch = charAt(i)
cs(i) = if (ch == from) to else ch
i += 1
}
newTermName(cs, 0, len)
}
/* TODO - reconcile/fix that encode returns a Name but
* decode returns a String.
*/
/** !!! Duplicative but consistently named.
*/
def decoded: String = decode
def encoded: String = "" + encode
// def decodedName: ThisNameType = newName(decoded)
def encodedName: ThisNameType = encode
/** Replace operator symbols by corresponding \$op_name. */
def encode: ThisNameType = {
val str = toString
val res = NameTransformer.encode(str)
if (res == str) thisName else newName(res)
}
/** Replace \$op_name by corresponding operator symbol. */
def decode: String = {
if (this containsChar '$') {
val str = toString
val res = NameTransformer.decode(str)
if (res == str) str
else res
}
else toString
}
/** TODO - find some efficiency. */
def append(ch: Char) = newName(toString + ch)
def append(suffix: String) = newName(toString + suffix)
def append(suffix: Name) = newName(toString + suffix)
def append(separator: Char, suffix: Name) = newName(toString + separator + suffix)
def prepend(prefix: String) = newName("" + prefix + this)
def decodedName: ThisNameType = newName(decode)
def isOperatorName: Boolean = decode != toString // used by ide
def longString: String = nameKind + " " + decode
def debugString = { val s = decode ; if (isTypeName) s + "!" else s }
}
implicit def AnyNameOps(name: Name): NameOps[Name] = new NameOps(name)
implicit def TermNameOps(name: TermName): NameOps[TermName] = new NameOps(name)
implicit def TypeNameOps(name: TypeName): NameOps[TypeName] = new NameOps(name)
/** FIXME: This is a good example of something which is pure "value class" but cannot
* reap the benefits because an (unused) $outer pointer so it is not single-field.
*/
final class NameOps[T <: Name](name: T) {
import NameTransformer._
def stripSuffix(suffix: String): T = if (name endsWith suffix) dropRight(suffix.length) else name // OPT avoid creating a Name with `suffix`
def stripSuffix(suffix: Name): T = if (name endsWith suffix) dropRight(suffix.length) else name
def take(n: Int): T = name.subName(0, n).asInstanceOf[T]
def drop(n: Int): T = name.subName(n, name.length).asInstanceOf[T]
def dropRight(n: Int): T = name.subName(0, name.length - n).asInstanceOf[T]
def dropLocal: TermName = name.toTermName stripSuffix LOCAL_SUFFIX_STRING
def dropSetter: TermName = name.toTermName stripSuffix SETTER_SUFFIX_STRING
def dropModule: T = this stripSuffix MODULE_SUFFIX_STRING
def localName: TermName = getterName append LOCAL_SUFFIX_STRING
def setterName: TermName = getterName append SETTER_SUFFIX_STRING
def getterName: TermName = dropTraitSetterSeparator.dropSetter.dropLocal
private def dropTraitSetterSeparator: TermName =
name indexOf TRAIT_SETTER_SEPARATOR_STRING match {
case -1 => name.toTermName
case idx => name.toTermName drop idx drop TRAIT_SETTER_SEPARATOR_STRING.length
}
}
implicit val NameTag = ClassTag[Name](classOf[Name])
/** A name that contains no operator chars nor dollar signs.
* TODO - see if it's any faster to do something along these lines.
* Cute: now that exhaustivity kind of works, the mere presence of
* this trait causes TermName and TypeName to stop being exhaustive.
* Commented out.
*/
// trait AlphaNumName extends Name {
// final override def encode = thisName
// final override def decodedName = thisName
// final override def decode = toString
// final override def isOperatorName = false
// }
/** TermName_S and TypeName_S have fields containing the string version of the name.
* TermName_R and TypeName_R recreate it each time toString is called.
*/
private final class TermName_S(index0: Int, len0: Int, hash: Int, override val toString: String) extends TermName(index0, len0, hash) {
protected def createCompanionName(h: Int): TypeName = new TypeName_S(index, len, h, toString)
override def newName(str: String): TermName = newTermNameCached(str)
}
private final class TypeName_S(index0: Int, len0: Int, hash: Int, override val toString: String) extends TypeName(index0, len0, hash) {
protected def createCompanionName(h: Int): TermName = new TermName_S(index, len, h, toString)
override def newName(str: String): TypeName = newTypeNameCached(str)
}
private final class TermName_R(index0: Int, len0: Int, hash: Int) extends TermName(index0, len0, hash) {
protected def createCompanionName(h: Int): TypeName = new TypeName_R(index, len, h)
override def toString = new String(chrs, index, len)
}
private final class TypeName_R(index0: Int, len0: Int, hash: Int) extends TypeName(index0, len0, hash) {
protected def createCompanionName(h: Int): TermName = new TermName_R(index, len, h)
override def toString = new String(chrs, index, len)
}
// SYNCNOTE: caller to constructor must synchronize if `synchronizeNames` is enabled
sealed abstract class TermName(index0: Int, len0: Int, hash: Int) extends Name(index0, len0) with TermNameApi {
type ThisNameType = TermName
protected[this] def thisName: TermName = this
val next: TermName = termHashtable(hash)
termHashtable(hash) = this
def isTermName: Boolean = true
def isTypeName: Boolean = false
def toTermName: TermName = this
def toTypeName: TypeName = {
def body = {
val h = hashValue(chrs, index, len) & HASH_MASK
var n = typeHashtable(h)
while ((n ne null) && n.start != index)
n = n.next
if (n ne null) n
else createCompanionName(h)
}
if (synchronizeNames) nameLock.synchronized(body) else body
}
def newName(str: String): TermName = newTermName(str)
def companionName: TypeName = toTypeName
def subName(from: Int, to: Int): TermName =
newTermName(chrs, start + from, to - from)
def nameKind = "term"
/** SYNCNOTE: caller must synchronize if `synchronizeNames` is enabled */
protected def createCompanionName(h: Int): TypeName
}
implicit val TermNameTag = ClassTag[TermName](classOf[TermName])
object TermName extends TermNameExtractor {
def apply(s: String) = newTermName(s)
def unapply(name: TermName): Option[String] = Some(name.toString)
}
sealed abstract class TypeName(index0: Int, len0: Int, hash: Int) extends Name(index0, len0) with TypeNameApi {
type ThisNameType = TypeName
protected[this] def thisName: TypeName = this
val next: TypeName = typeHashtable(hash)
typeHashtable(hash) = this
def isTermName: Boolean = false
def isTypeName: Boolean = true
def toTermName: TermName = {
def body = {
val h = hashValue(chrs, index, len) & HASH_MASK
var n = termHashtable(h)
while ((n ne null) && n.start != index)
n = n.next
if (n ne null) n
else createCompanionName(h)
}
if (synchronizeNames) nameLock.synchronized(body) else body
}
def toTypeName: TypeName = this
def newName(str: String): TypeName = newTypeName(str)
def companionName: TermName = toTermName
def subName(from: Int, to: Int): TypeName =
newTypeName(chrs, start + from, to - from)
def nameKind = "type"
override def decode = if (nameDebug) super.decode + "!" else super.decode
/** SYNCNOTE: caller must synchronize if `synchronizeNames` is enabled */
protected def createCompanionName(h: Int): TermName
}
implicit val TypeNameTag = ClassTag[TypeName](classOf[TypeName])
object TypeName extends TypeNameExtractor {
def apply(s: String) = newTypeName(s)
def unapply(name: TypeName): Option[String] = Some(name.toString)
}
}
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