/// <summary>
/// Tries to create a filtered workspace based on a front-end snapshot from the previous BuildXL invocation.
/// </summary>
/// <returns>
/// * Possibke<ValidConstructedWorkspace> when the workspace was successfully constructed.
/// * Possible<null> when the snapshot was unaiable.
/// * Failure when the snapshot was available but parsing failed.
/// </returns>
private async Task <Possible <Workspace> > TryCreateFilteredWorkspaceAsync(Possible <WorkspaceDefinition> workspaceDefinition, IWorkspaceProvider workspaceProvider, FrontEndEngineAbstraction engineAbstraction, EvaluationFilter evaluationFilter)
{
if (!FrontEndConfiguration.ConstructAndSaveBindingFingerprint())
{
Logger.FailToReuseFrontEndSnapshot(
LoggingContext,
"Binding fingerprint is disabled. Please use 'constructAndSaveBindingFingerprint' option to turn it on");
return(default(Possible <Workspace>));
}
// If a filter cannot be performed and public facade + AST is not to be used, then there is no point in continuing and we can
// go to full mode
if (!evaluationFilter.CanPerformPartialEvaluationScript(PrimaryConfigFile) && !CanUseSpecPublicFacadeAndAst())
{
var message = !CanUseSpecPublicFacadeAndAst()
? "Engine state was not reloaded"
: "User filter was not specified";
Logger.FailToReuseFrontEndSnapshot(LoggingContext, message);
return(default(Possible <Workspace>));
}
var changedFiles = engineAbstraction.GetChangedFiles()?.ToList();
if (changedFiles == null)
{
Logger.FailToReuseFrontEndSnapshot(LoggingContext, "Change journal is not available");
return(default(Possible <Workspace>));
}
using (var sw = Watch.Start())
{
// We're potentially in incremental mode.
var filteredDefinitionResult = await TryFilterWorkspaceDefinitionIncrementallyAsync(
changedFiles,
workspaceProvider,
workspaceDefinition.Result,
evaluationFilter);
if (filteredDefinitionResult.Failed)
{
return(filteredDefinitionResult.Failure);
}
if (filteredDefinitionResult.Filtered)
{
var filteredDefinition = filteredDefinitionResult.FilteredDefinition;
Logger.WorkspaceDefinitionFiltered(
LoggingContext,
filteredDefinition.SpecCount,
workspaceDefinition.Result.SpecCount,
sw.ElapsedMilliseconds);
// TODO: with C# 7, use tuple instead of changing the workspace to carry the information about the filtering.
return(await workspaceProvider.CreateWorkspaceAsync(filteredDefinition, userFilterWasApplied : true));
}
}
return(default(Possible <Workspace>));
}
/// <summary>
/// Returns <code>true</code> IFF information about both changed and unchanged files is available.
/// <see cref="FrontEndEngineAbstraction.GetChangedFiles"/>
/// <see cref="FrontEndEngineAbstraction.GetUnchangedFiles"/>
/// </summary>
/// <remarks>
/// Information about changed files may not always be available, e.g., because engine cache is missing,
/// engine cache is corrupted, USNJournal is not working, etc.
/// </remarks>
public static bool IsSpecChangeInformationAvailable(this FrontEndEngineAbstraction engineAbstraction)
{
return
(engineAbstraction.GetChangedFiles() != null &&
engineAbstraction.GetUnchangedFiles() != null);
}