/// <summary>
/// create caret preserving edit transaction with automatic code change undo merging policy
/// </summary>
public static CaretPreservingEditTransaction CreateEditTransaction(
this ITextView view, string description, ITextUndoHistoryRegistry registry, IEditorOperationsFactoryService service)
{
var transaction = new CaretPreservingEditTransaction(description, view, registry, service);
transaction.MergePolicy = AutomaticCodeChangeMergePolicy.Instance;
return transaction;
}
private void Commit(
PresentationItem item, Model model, char? commitChar,
ITextSnapshot initialTextSnapshot, Action nextHandler)
{
AssertIsForeground();
// We could only be called if we had a model at this point.
Contract.ThrowIfNull(model);
// Now that we've captured the model at this point, we can stop ourselves entirely.
// This is also desirable as we may have reentrancy problems when we call into
// custom commit completion providers. I.e. if the custom provider moves the caret,
// then we do not want to process that move as it may put us into an unexpected state.
//
// TODO(cyrusn): We still have a general reentrancy problem where calling into a custom
// commit provider (or just calling into the editor) may cause something to call back
// into us. However, for now, we just hope that no such craziness will occur.
this.StopModelComputation();
CompletionChange completionChange;
using (var transaction = new CaretPreservingEditTransaction(
EditorFeaturesResources.IntelliSense, TextView, _undoHistoryRegistry, _editorOperationsFactoryService))
{
// We want to merge with any of our other programmatic edits (e.g. automatic brace completion)
transaction.MergePolicy = AutomaticCodeChangeMergePolicy.Instance;
var provider = GetCompletionProvider(item.Item) as ICustomCommitCompletionProvider;
if (provider != null)
{
provider.Commit(item.Item, this.TextView, this.SubjectBuffer, model.TriggerSnapshot, commitChar);
}
else
{
// Right before calling Commit, we may have passed the commitChar through to the
// editor. That was so that undoing completion will get us back to the state we
// we would be in if completion had done nothing. However, now that we're going
// to actually commit, we want to roll back to where we were before we pushed
// commit character into the buffer. This has multiple benefits:
//
// 1) the buffer is in a state we expect it to be in. i.e. we don't have to
// worry about what might have happened (like brace-completion) when the
// commit char was inserted.
// 2) after we commit the item, we'll pass the commit character again into the
// buffer (unless the items asks us not to). By doing this, we can make sure
// that things like brace-completion or formatting trigger as we expect them
// to.
var characterWasSentIntoBuffer = commitChar != null &&
initialTextSnapshot.Version.VersionNumber != this.SubjectBuffer.CurrentSnapshot.Version.VersionNumber;
if (characterWasSentIntoBuffer)
{
RollbackToBeforeTypeChar(initialTextSnapshot);
}
// Now, get the change the item wants to make. Note that the change will be relative
// to the initial snapshot/document the item was triggered from. We'll map that change
// forward, then apply it to our current snapshot.
var triggerDocument = model.TriggerDocument;
var triggerSnapshot = model.TriggerSnapshot;
var completionService = CompletionService.GetService(triggerDocument);
Contract.ThrowIfNull(completionService, nameof(completionService));
completionChange = completionService.GetChangeAsync(
triggerDocument, item.Item, commitChar, CancellationToken.None).WaitAndGetResult(CancellationToken.None);
var textChange = completionChange.TextChange;
var triggerSnapshotSpan = new SnapshotSpan(triggerSnapshot, textChange.Span.ToSpan());
var mappedSpan = triggerSnapshotSpan.TranslateTo(
this.SubjectBuffer.CurrentSnapshot, SpanTrackingMode.EdgeInclusive);
// Now actually make the text change to the document.
using (var textEdit = this.SubjectBuffer.CreateEdit(EditOptions.None, reiteratedVersionNumber: null, editTag: null))
{
var adjustedNewText = AdjustForVirtualSpace(textChange);
textEdit.Replace(mappedSpan.Span, adjustedNewText);
textEdit.Apply();
}
// adjust the caret position if requested by completion service
if (completionChange.NewPosition != null)
{
TextView.Caret.MoveTo(new SnapshotPoint(
this.SubjectBuffer.CurrentSnapshot, completionChange.NewPosition.Value));
}
// Now, pass along the commit character unless the completion item said not to
if (characterWasSentIntoBuffer && !completionChange.IncludesCommitCharacter)
{
nextHandler();
}
// If the insertion is long enough, the caret will scroll out of the visible area.
// Re-center the view.
this.TextView.Caret.EnsureVisible();
}
transaction.Complete();
}
// Let the completion rules know that this item was committed.
this.MakeMostRecentItem(item.Item.DisplayText);
}