/*
* Creates a <code>RangeDifference3</code> given the state of two
* DifferenceIterators.
*/
private static RangeDifference createRangeDifference3(
DifferencesIterator myIter,
DifferencesIterator yourIter,
List diff3,
IRangeComparator right,
IRangeComparator left,
int changeRangeStart,
int changeRangeEnd) {
int rightStart, rightEnd;
int leftStart, leftEnd;
int kind = RangeDifference.ERROR;
RangeDifference last = (RangeDifference) diff3.get(diff3.size() - 1);
Assert.isTrue((myIter.getCount() != 0 || yourIter.getCount() != 0)); // At
// least
// one
// range
// array
// must
// be
// non-empty
//
// find corresponding lines to fChangeRangeStart/End in right and left
//
if (myIter.getCount() == 0) { // only left changed
rightStart = changeRangeStart - last.ancestorEnd() + last.rightEnd();
rightEnd = changeRangeEnd - last.ancestorEnd() + last.rightEnd();
kind = RangeDifference.LEFT;
} else {
RangeDifference f = (RangeDifference) myIter.fRange.get(0);
RangeDifference l = (RangeDifference) myIter.fRange.get(myIter.fRange.size() - 1);
rightStart = changeRangeStart - f.fLeftStart + f.fRightStart;
rightEnd = changeRangeEnd - l.leftEnd() + l.rightEnd();
}
if (yourIter.getCount() == 0) { // only right changed
leftStart = changeRangeStart - last.ancestorEnd() + last.leftEnd();
leftEnd = changeRangeEnd - last.ancestorEnd() + last.leftEnd();
kind = RangeDifference.RIGHT;
} else {
RangeDifference f = (RangeDifference) yourIter.fRange.get(0);
RangeDifference l = (RangeDifference) yourIter.fRange.get(yourIter.fRange.size() - 1);
leftStart = changeRangeStart - f.fLeftStart + f.fRightStart;
leftEnd = changeRangeEnd - l.leftEnd() + l.rightEnd();
}
if (kind == RangeDifference.ERROR) { // overlapping change (conflict)
// -> compare the changed ranges
if (rangeSpansEqual(
right, rightStart, rightEnd - rightStart, left, leftStart, leftEnd - leftStart))
kind = RangeDifference.ANCESTOR;
else kind = RangeDifference.CONFLICT;
}
return new RangeDifference(
kind,
rightStart,
rightEnd - rightStart,
leftStart,
leftEnd - leftStart,
changeRangeStart,
changeRangeEnd - changeRangeStart);
}
/**
* Finds the differences among three <code>IRangeComparator</code>s. The differences are returned
* as a list of <code>RangeDifference</code>s. If no differences are detected an empty list is
* returned. If the ancestor range comparator is <code>null</code>, a two-way comparison is
* performed.
*
* @param pm if not <code>null</code> used to report progress
* @param ancestor the ancestor range comparator or <code>null</code>
* @param left the left range comparator
* @param right the right range comparator
* @return an array of range differences, or an empty array if no differences were found
* @since 2.0
*/
public static RangeDifference[] findDifferences(
IProgressMonitor pm,
LCSSettings settings,
IRangeComparator ancestor,
IRangeComparator left,
IRangeComparator right) {
try {
if (ancestor == null) return findDifferences(pm, settings, left, right);
SubMonitor monitor = SubMonitor.convert(pm, CompareMessages.RangeComparatorLCS_0, 100);
RangeDifference[] leftAncestorScript = null;
RangeDifference[] rightAncestorScript =
findDifferences(monitor.newChild(50), settings, ancestor, right);
if (rightAncestorScript != null) {
monitor.setWorkRemaining(100);
leftAncestorScript = findDifferences(monitor.newChild(50), settings, ancestor, left);
}
if (rightAncestorScript == null || leftAncestorScript == null) return null;
DifferencesIterator myIter = new DifferencesIterator(rightAncestorScript);
DifferencesIterator yourIter = new DifferencesIterator(leftAncestorScript);
List diff3 = new ArrayList();
diff3.add(new RangeDifference(RangeDifference.ERROR)); // add a
// sentinel
int changeRangeStart = 0;
int changeRangeEnd = 0;
//
// Combine the two two-way edit scripts into one
//
monitor.setWorkRemaining(rightAncestorScript.length + leftAncestorScript.length);
while (myIter.fDifference != null || yourIter.fDifference != null) {
DifferencesIterator startThread;
myIter.removeAll();
yourIter.removeAll();
//
// take the next diff that is closer to the start
//
if (myIter.fDifference == null) startThread = yourIter;
else if (yourIter.fDifference == null) startThread = myIter;
else { // not at end of both scripts take the lowest range
if (myIter.fDifference.fLeftStart <= yourIter.fDifference.fLeftStart) // 2
// ->
// common
// (Ancestor)
// change
// range
startThread = myIter;
else startThread = yourIter;
}
changeRangeStart = startThread.fDifference.fLeftStart;
changeRangeEnd = startThread.fDifference.leftEnd();
startThread.next();
monitor.worked(1);
//
// check for overlapping changes with other thread
// merge overlapping changes with this range
//
DifferencesIterator other = startThread.other(myIter, yourIter);
while (other.fDifference != null && other.fDifference.fLeftStart <= changeRangeEnd) {
int newMax = other.fDifference.leftEnd();
other.next();
monitor.worked(1);
if (newMax >= changeRangeEnd) {
changeRangeEnd = newMax;
other = other.other(myIter, yourIter);
}
}
diff3.add(
createRangeDifference3(
myIter, yourIter, diff3, right, left, changeRangeStart, changeRangeEnd));
}
// remove sentinel
diff3.remove(0);
return (RangeDifference[]) diff3.toArray(EMPTY_RESULT);
} finally {
if (pm != null) pm.done();
}
}
