/// <summary>
/// A cleanup rewrites the diff, it optimises the diff to be efficient for machine processing.
/// </summary>
/* The results of both cleanup types are often the same. The efficiency cleanup is based on the observation that a diff made up of
* large numbers of small diffs edits may take longer to process (in downstream applications) or take more capacity to store or transmit than a
* smaller number of larger diffs. The diff_match_patch.Diff_EditCost property sets what the cost of handling a new edit is in terms of handling
* extra characters in an existing edit. The default value is 4, which means if expanding the length of a diff by three characters can eliminate
* one edit, then that optimisation will reduce the total costs. */
public void CleanupEfficiency()
{
if (diffs == null)
{
return;
}
diffMatchPatch.diff_cleanupEfficiency(diffs);
}
/// <summary>
/// Creates a patch from the PatchMessage sent by the client.
/// Then applies the patch to the ShadowCopy followed by applying the patch to the live server copy.
/// Then creates new diffs from the live server text and the shadow (which contains the exact copy of latest client message).
/// These diffs will then be send to the client so that the client now has the latest updates.
/// </summary>
/// <param name="message"></param>
private void HandlePatchMessage(PatchMessage message)
{
_edits.Clear();
Edit edit = message.Edits.Pop();
Task.Factory.StartNew(() =>
{
if (edit.ClientVersion > User.Document.ShadowCopy.ClientVersion || edit.ClientVersion == 0)
{
// Update Server Shadow
bool success;
List <Patch> patches;
try
{
patches = _dmp.patch_make(User.Document.ShadowCopy.ShadowText, edit.Diffs);
User.Document.ShadowCopy.ShadowText =
_dmp.patch_apply(patches, User.Document.ShadowCopy.ShadowText)[0].ToString();
//User.Document.ShadowCopy.ClientVersion++;
User.Document.BackupShadowCopy.BackupText = User.Document.ShadowCopy.ShadowText;
success = true;
}
catch (ArgumentOutOfRangeException e)
{
Console.WriteLine(e);
success = false;
Session.BroadCastOutOfSyncResponse(Session.Document.CurrentText);
}
if (success)
{
// Update Server Current
patches = _dmp.patch_make(Session.Document.CurrentText, edit.Diffs);
Session.Document.CurrentText =
_dmp.patch_apply(patches, Session.Document.CurrentText)[0].ToString();
Console.WriteLine(
$"Updated client: {User.Username}, With test: {Session.Document.CurrentText}");
}
}
}).ContinueWith((result) =>
{
List <Diff> diffs = _dmp.diff_main(User.Document.ShadowCopy.ShadowText, Session.Document.CurrentText,
false);
_dmp.diff_cleanupEfficiency(diffs);
_edits.Push(new Edit(diffs, User.Document.ShadowCopy.ClientVersion,
User.Document.ShadowCopy.ServerVersion));
SendMessage(new PatchMessage("Server", _edits));
User.Document.ShadowCopy.ShadowText = Session.Document.CurrentText;
_edits.Clear();
});
}