internal int EnsureSelfAndChildrenNoLongerThan(int maxLength)
{
Contract.Requires <ArgumentOutOfRangeException>(maxLength > 0, "A path can only have a positive length.");
Contract.Requires <ArgumentOutOfRangeException>(this.Parent == null || maxLength > this.Parent.FullLength + 1, "A child path cannot possibly be made shorter than its parent.");
Contract.Ensures(Contract.Result <int>() <= maxLength);
const int uniqueBase = 16;
// Find the items that are too long, and always work on the longest one
var longPaths = this.SelfAndDescendents.Where(path => path.FullLength > maxLength).OrderByDescending(path => path.FullLength);
PathSegment longPath;
while ((longPath = longPaths.FirstOrDefault()) != null)
{
// Keep working on this one until it's short enough.
do
{
int tooLongBy = longPath.FullLength - maxLength;
var longSegments = longPath.SelfAndAncestors.Where(segment => !segment.minimized).OrderByDescending(segment => segment.CurrentName.Length);
PathSegment longestSegment = longSegments.FirstOrDefault();
if (longestSegment == null)
{
throw new InvalidOperationException("Unable to shrink path length sufficiently.");
}
PathSegment secondLongestSegment = longSegments.Skip(1).FirstOrDefault();
int shortenByUpTo;
if (secondLongestSegment != null)
{
shortenByUpTo = Math.Min(tooLongBy, Math.Max(1, longestSegment.CurrentName.Length - secondLongestSegment.CurrentName.Length));
}
else
{
shortenByUpTo = tooLongBy;
}
int minimumGuaranteedUniqueLength = Math.Max(1, RoundUp(Math.Log(longestSegment.Siblings.Count(), uniqueBase)));
int allowableSegmentLength = Math.Max(minimumGuaranteedUniqueLength, longestSegment.CurrentName.Length - shortenByUpTo);
if (allowableSegmentLength >= longestSegment.CurrentName.Length)
{
// We can't make this segment any shorter.
longestSegment.minimized = true;
}
longestSegment.currentName = longestSegment.CreateUniqueShortFileName(longestSegment.CurrentName, allowableSegmentLength);
} while (longPath.FullLength > maxLength);
}
// Return the total length of self or longest child.
return(this.SelfAndDescendents.Max(c => c.FullLength));
}
