/// <summary>
/// Initializes a new instance of a <see cref="TextVersion"/>.
/// </summary>
/// <param name="textBuffer">The <see cref="ITextBuffer"/> to which the version belongs.</param>
/// <param name="imageVersion">The <see cref="ITextImageVersion"/> of the associated snapshot.</param>
public TextVersion(ITextBuffer textBuffer, TextImageVersion imageVersion)
{
if (textBuffer == null)
{
throw new ArgumentNullException(nameof(textBuffer));
}
if (imageVersion == null)
{
throw new ArgumentNullException(nameof(imageVersion));
}
this.TextBuffer = textBuffer;
_textImageVersion = imageVersion;
}
internal TextImageVersion CreateNext(int reiteratedVersionNumber, int length, INormalizedTextChangeCollection changes)
{
int newVersionNumber = this.VersionNumber + 1;
if (reiteratedVersionNumber < 0)
{
// If there are no changes (e.g. readonly region edit or content type change), then
// we consider this a reiteration of the current version. changes can be null in the special case
// of doing a reload (at which point the reload code will call SetChanges after computing the diff).
reiteratedVersionNumber = ((changes != null) && (changes.Count == 0)) ? this.ReiteratedVersionNumber : newVersionNumber;
}
else if (reiteratedVersionNumber > newVersionNumber)
{
throw new ArgumentOutOfRangeException(nameof(reiteratedVersionNumber));
}
if (length == -1)
{
length = this.Length;
int changeCount = changes.Count;
for (int c = 0; c < changeCount; ++c)
{
length += changes[c].Delta;
}
}
var newVersion = new TextImageVersion(newVersionNumber, reiteratedVersionNumber, length, this.Identifier);
// Arguably this should happen as an atomic operation but it is unlikely to cause a race condition
// because, in general, people won't even be looking at these properties until they get a change event
// (which happens after everything has been set).
this.SetChanges(changes);
this.Next = newVersion;
return(newVersion);
}
