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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.runtime.types;
import scala.Type;
import scala.Array;
import scala.ScalaObject;
import scala.runtime.RunTime;
import scala.runtime.FNV_Hash;
import scala.runtime.PearsonHash;
public class ScalaClassType extends ClassType {
public static final ScalaClassType[] EMPTY_ARRAY =
new ScalaClassType[0];
private static final ScalaClassType[][] EMPTY_ANCESTORS =
new ScalaClassType[0][];
private final TypeConstructor constr;
private final Type[] inst;
private ScalaClassType[] parents;
private ScalaClassType[][] ancestors = null;
private final int hashCode;
public ScalaClassType(TypeConstructor constr,
Type[] inst,
ScalaClassType[] parents) {
super(constr.clazz, constr.isTrivial);
this.constr = constr;
this.inst = inst;
int hash = FNV_Hash.hashStep(FNV_Hash.INIT,
PearsonHash.hash8(constr.hashCode()));
for (int i = 0; i < inst.length; ++i) {
hash = FNV_Hash.hashStep(hash,
PearsonHash.hash8(inst[i].hashCode()));
}
this.hashCode = hash;
this.parents = parents;
this.ancestors = constr.isStronglyTrivial ? EMPTY_ANCESTORS : null;
}
public boolean isInstance(Object o) {
return super.isInstance(o)
&& (isTrivial
|| ((ScalaObject)o).getScalaType().isNonTrivialSubClassType(this));
}
public boolean isNonTrivialInstance(Object o) {
assert Statistics.incWeakInstanceOf();
return ((ScalaObject)o).getScalaType().isNonTrivialSubClassType(this);
}
protected boolean isSubClassType(ClassType that) {
return (this == that)
|| (super.isSubClassType(that)
&& (that.isTrivial
|| isNonTrivialSubClassType((ScalaClassType)that)));
}
public boolean isNonTrivialSubClassType(ClassType that) {
ScalaClassType thatCT = (ScalaClassType)that;
ScalaClassType parentCT = myInstantiationFor(thatCT);
// At this stage, if parentCT is null, it means that the
// constructors had different prefixes, hence we return false.
return (parentCT != null)
&& (parentCT == thatCT || parentCT.hasSubInstantiation(thatCT));
}
// Return true iff the instantiation of THIS is "smaller" than the
// one of THAT.
private boolean hasSubInstantiation(ScalaClassType that) {
assert this.constr == that.constr;
final Type[] thisInst = this.inst;
final Type[] thatInst = that.inst;
int i = 0;
// invariant parameters
final int firstM = this.constr.zCount;
while (i < firstM) {
Type thisTp = thisInst[i], thatTp = thatInst[i];
if (!(thisTp == thatTp || thisTp.isSameType(thatTp)))
return false;
++i;
}
// contravariant parameters
final int firstP = firstM + this.constr.mCount;
while (i < firstP) {
Type thisTp = thisInst[i], thatTp = thatInst[i];
if (!(thisTp == thatTp || thatTp.isSubType(thisTp)))
return false;
++i;
}
// covariant parameters
final int firstOutside = firstP + this.constr.pCount;
while (i < firstOutside) {
Type thisTp = thisInst[i], thatTp = thatInst[i];
if (!(thisTp == thatTp || thisTp.isSubType(thatTp)))
return false;
++i;
}
return true;
}
public boolean isSameType(Type that) {
return this == that;
}
private ScalaClassType myInstantiationFor(ScalaClassType that) {
// Find our instantiation for the other type, if any.
ScalaClassType[] thisSlice = getAncestors()[that.constr.level];
for (int i = 0; i < thisSlice.length; ++i) {
if (thisSlice[i].constr == that.constr) {
assert Statistics.addAncestorSearchIterations(i + 1);
return thisSlice[i];
}
}
assert Statistics.addAncestorSearchIterations(thisSlice.length);
return null;
}
public String toString() {
StringBuffer buf = new StringBuffer();
int firstM = constr.zCount;
int firstP = firstM + constr.mCount;
buf.append(constr);
if (inst.length > 0) {
buf.append("[");
for (int i = 0; i < inst.length; ++i) {
if (i > 0) buf.append(", ");
if (i >= firstP)
buf.append('+');
else if (i >= firstM)
buf.append('-');
buf.append(inst[i]);
}
buf.append("]");
}
return buf.toString();
}
public int hashCode() {
return hashCode;
}
public ScalaClassType setParents(ScalaClassType[] parents) {
assert this.parents == null || Type.isSameType(this.parents, parents);
this.parents = parents;
// TODO notifyAll?
return this;
}
public ScalaClassType[] getParents() {
int timeout = 1;
while (parents == null) {
try {
wait(timeout);
} catch (InterruptedException e) {
throw new Error(e);
}
timeout *= 2;
if (timeout >= 1000)
throw new Error("computation of parents apparently stuck for "
+ this);
}
return parents;
}
private ScalaClassType[][] getAncestors() {
if (ancestors == null)
computeAncestors();
return ancestors;
}
private void computeAncestors() {
final int level = constr.level;
final int ancestorDepth = constr.ancestorCacheDepth;
final int[] ancestorCode = constr.ancestorCode;
ScalaClassType[] parents = getParents();
ancestors = new ScalaClassType[ancestorDepth][];
ScalaClassType[][] initialAncestors = parents.length > 0
? parents[0].getAncestors()
: EMPTY_ANCESTORS;
for (int l = 0, dci = 0; l < ancestorDepth; ++l) {
int toAddParents = 0;
if (dci < ancestorCode.length && ancestorCode[dci] == l) {
dci++;
toAddParents = ancestorCode[dci++];
}
int toAddSelf = (l == level) && (!constr.isTrivial) ? 1 : 0;
int toAdd = toAddParents + toAddSelf;
ScalaClassType[] initialRow;
if (l < initialAncestors.length)
initialRow = initialAncestors[l];
else
initialRow = ScalaClassType.EMPTY_ARRAY;
if (toAdd == 0) {
ancestors[l] = initialRow;
} else {
int initialLen = initialRow.length;
ScalaClassType[] newRow =
new ScalaClassType[initialLen + toAdd];
if (toAddSelf == 1)
newRow[0] = this;
System.arraycopy(initialRow, 0, newRow, toAddSelf, initialLen);
for (int i = 0; i < toAddParents; ++i) {
int p = ancestorCode[dci++];
int o = ancestorCode[dci++];
newRow[toAddSelf + initialLen + i] =
parents[p].getAncestors()[l][o];
}
ancestors[l] = newRow;
}
}
}
}
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