/// <remarks>
/// Once a preview object is returned from this function, the ownership of this preview object is
/// transferred to the caller. It is the caller's responsibility to ensure that the preview object
/// will be properly disposed (i.e. that any contained IWpfTextViews will be properly closed).
///
/// This function guarantees that it will not return the same preview object twice if called twice
/// (thereby reducing the possibility that a given preview object can end up with more than one owner).
/// </remarks>
public object TakeNextPreview(DocumentId preferredDocumentId = null, ProjectId preferredProjectId = null)
{
if (IsEmpty)
{
return(null);
}
SolutionPreviewItem previewItem = null;
// Check if we have a preview for some change within the supplied preferred document.
if (preferredDocumentId != null)
{
previewItem = _previews.Where(p => p.DocumentId == preferredDocumentId).FirstOrDefault();
}
// Check if we have a preview for some change within the supplied preferred project.
if ((previewItem == null) && (preferredProjectId != null))
{
previewItem = _previews.Where(p => p.ProjectId == preferredProjectId).FirstOrDefault();
}
// We don't have a preview matching the preferred document or project. Return the first preview.
if (previewItem == null)
{
previewItem = _previews.FirstOrDefault();
}
// We should now remove this preview object from the list so that it can not be returned again
// if someone calls this function again (thereby reducing the possibility that a given preview
// object can end up with more than one owner - see <remarks> above).
_previews.Remove(previewItem);
return(previewItem.Preview.Value);
}
public SolutionPreviewResult(
IThreadingContext threadingContext,
SolutionPreviewItem preview,
SolutionChangeSummary changeSummary = null
) : this(threadingContext, new List <SolutionPreviewItem> {
preview
}, changeSummary)
{
}
/// <remarks>
/// Once a preview object is returned from this function, the ownership of this preview object is
/// transferred to the caller. It is the caller's responsibility to ensure that the preview object
/// will be properly disposed (i.e. that any contained IWpfTextViews will be properly closed).
///
/// This function guarantees that it will not return the same preview object twice if called twice
/// (thereby reducing the possibility that a given preview object can end up with more than one owner).
/// </remarks>
public async Task <object> TakeNextPreviewAsync(DocumentId preferredDocumentId = null, ProjectId preferredProjectId = null, CancellationToken cancellationToken = default(CancellationToken))
{
AssertIsForeground();
cancellationToken.ThrowIfCancellationRequested();
if (IsEmpty)
{
return(null);
}
SolutionPreviewItem previewItem = null;
// Check if we have a preview for some change within the supplied preferred document.
if (preferredDocumentId != null)
{
previewItem = _previews.Where(p => p.DocumentId == preferredDocumentId).FirstOrDefault();
}
// Check if we have a preview for some change within the supplied preferred project.
if ((previewItem == null) && (preferredProjectId != null))
{
previewItem = _previews.Where(p => p.ProjectId == preferredProjectId).FirstOrDefault();
}
// We don't have a preview matching the preferred document or project. Return the first preview.
if (previewItem == null)
{
previewItem = _previews.FirstOrDefault();
}
cancellationToken.ThrowIfCancellationRequested();
// We should now remove this preview object from the list so that it can not be returned again
// if someone calls this function again (thereby reducing the possibility that a given preview
// object can end up with more than one owner - see <remarks> above).
_previews.Remove(previewItem);
// We use ConfigureAwait(true) to stay on the UI thread.
var preview = await previewItem.LazyPreview(cancellationToken).ConfigureAwait(true);
if (preview == null)
{
// Keep going if preview is null. Null preview indicates that although the preferred document was marked as changed,
// there are no textual changes in the preferred document and so we can't create a diff preview for this docuement.
// This can happen in the case of the 'rename tracking' code fix - the document where the fix was triggered from (i.e.
// the preferred document) is always reported as changed (on account of difference in docuemnt version). However, if
// the renamed identifier is not referenced from any other location in this document, then there will be no text changes
// between the two versions. In such cases, We should keep going until we find a document with text changes that can be
// diffed and previewed.
// There is no danger of infinite recursion here since we remove null previews from the list each time.
preview = await TakeNextPreviewAsync(preferredDocumentId, preferredProjectId, cancellationToken).ConfigureAwait(true);
}
return(preview);
}
public SolutionPreviewResult(SolutionPreviewItem preview, SolutionChangeSummary changeSummary = null)
: this(new List <SolutionPreviewItem> {
preview
}, changeSummary)
{
}
public SolutionPreviewResult(SolutionPreviewItem preview, SolutionChangeSummary changeSummary = null)
: this(new List<SolutionPreviewItem> { preview }, changeSummary)
{
}
