internal async Task ExecuteTarget()

in src/Build/BackEnd/Components/RequestBuilder/TargetEntry.cs [388:667]


        internal async Task ExecuteTarget(ITaskBuilder taskBuilder, BuildRequestEntry requestEntry, ProjectLoggingContext projectLoggingContext, CancellationToken cancellationToken)
        {
#if MSBUILDENABLEVSPROFILING 
            try
            {
                string beginTargetBuild = String.Format(CultureInfo.CurrentCulture, "Build Target {0} in Project {1} - Start", this.Name, projectFullPath);
                DataCollection.CommentMarkProfile(8800, beginTargetBuild);
#endif 

            try
            {
                VerifyState(_state, TargetEntryState.Execution);
                ErrorUtilities.VerifyThrow(!_isExecuting, "Target {0} is already executing", _target.Name);
                _cancellationToken = cancellationToken;
                _isExecuting = true;

                // Generate the batching buckets.  Note that each bucket will get a lookup based on the baseLookup.  This lookup will be in its
                // own scope, which we will collapse back down into the baseLookup at the bottom of the function.
                List<ItemBucket> buckets = BatchingEngine.PrepareBatchingBuckets(GetBatchableParametersForTarget(), _baseLookup, _target.Location);

                WorkUnitResult aggregateResult = new WorkUnitResult();
                TargetLoggingContext targetLoggingContext = null;
                bool targetSuccess = false;
                int numberOfBuckets = buckets.Count;
                string projectFullPath = requestEntry.RequestConfiguration.ProjectFullPath;

                string parentTargetName = null;
                if (ParentEntry != null && ParentEntry.Target != null)
                {
                    parentTargetName = ParentEntry.Target.Name;
                }

                for (int i = 0; i < numberOfBuckets; i++)
                {
                    ItemBucket bucket = buckets[i];

                    // If one of the buckets failed, stop building.
                    if (aggregateResult.ActionCode == WorkUnitActionCode.Stop)
                    {
                        break;
                    }

                    targetLoggingContext = projectLoggingContext.LogTargetBatchStarted(projectFullPath, _target, parentTargetName);
                    WorkUnitResult bucketResult = null;
                    targetSuccess = false;

                    Lookup.Scope entryForInference = null;
                    Lookup.Scope entryForExecution = null;

                    try
                    {
                        // This isn't really dependency analysis.  This is up-to-date checking.  Based on this we will be able to determine if we should
                        // run tasks in inference or execution mode (or both) or just skip them altogether.
                        ItemDictionary<ProjectItemInstance> changedTargetInputs;
                        ItemDictionary<ProjectItemInstance> upToDateTargetInputs;
                        Lookup lookupForInference;
                        Lookup lookupForExecution;

                        // UNDONE: (Refactor) Refactor TargetUpToDateChecker to take a logging context, not a logging service.
                        TargetUpToDateChecker dependencyAnalyzer = new TargetUpToDateChecker(requestEntry.RequestConfiguration.Project, _target, targetLoggingContext.LoggingService, targetLoggingContext.BuildEventContext);
                        DependencyAnalysisResult dependencyResult = dependencyAnalyzer.PerformDependencyAnalysis(bucket, out changedTargetInputs, out upToDateTargetInputs);

                        switch (dependencyResult)
                        {
                            // UNDONE: Need to enter/leave debugger scope properly for the <Target> element.
                            case DependencyAnalysisResult.FullBuild:
                            case DependencyAnalysisResult.IncrementalBuild:
                            case DependencyAnalysisResult.SkipUpToDate:
                                // Create the lookups used to hold the current set of properties and items
                                lookupForInference = bucket.Lookup;
                                lookupForExecution = bucket.Lookup.Clone();

                                // Push the lookup stack up one so that we are only modifying items and properties in that scope.
                                entryForInference = lookupForInference.EnterScope("ExecuteTarget() Inference");
                                entryForExecution = lookupForExecution.EnterScope("ExecuteTarget() Execution");

                                // if we're doing an incremental build, we need to effectively run the task twice -- once
                                // to infer the outputs for up-to-date input items, and once to actually execute the task;
                                // as a result we need separate sets of item and property collections to track changes
                                if (dependencyResult == DependencyAnalysisResult.IncrementalBuild)
                                {
                                    // subset the relevant items to those that are up-to-date
                                    foreach (string itemType in upToDateTargetInputs.ItemTypes)
                                    {
                                        lookupForInference.PopulateWithItems(itemType, upToDateTargetInputs[itemType]);
                                    }

                                    // subset the relevant items to those that have changed
                                    foreach (string itemType in changedTargetInputs.ItemTypes)
                                    {
                                        lookupForExecution.PopulateWithItems(itemType, changedTargetInputs[itemType]);
                                    }
                                }

                                // We either have some work to do or at least we need to infer outputs from inputs.
                                bucketResult = await ProcessBucket(taskBuilder, targetLoggingContext, GetTaskExecutionMode(dependencyResult), lookupForInference, lookupForExecution);

                                // Now aggregate the result with the existing known results.  There are four rules, assuming the target was not 
                                // skipped due to being up-to-date:
                                // 1. If this bucket failed or was cancelled, the aggregate result is failure.
                                // 2. If this bucket Succeeded and we have not previously failed, the aggregate result is a success.
                                // 3. Otherwise, the bucket was skipped, which has no effect on the aggregate result.
                                // 4. If the bucket's action code says to stop, then we stop, regardless of the success or failure state.
                                if (dependencyResult != DependencyAnalysisResult.SkipUpToDate)
                                {
                                    aggregateResult = aggregateResult.AggregateResult(bucketResult);
                                }
                                else
                                {
                                    if (aggregateResult.ResultCode == WorkUnitResultCode.Skipped)
                                    {
                                        aggregateResult = aggregateResult.AggregateResult(new WorkUnitResult(WorkUnitResultCode.Success, WorkUnitActionCode.Continue, null));
                                    }
                                }

                                // Pop the lookup scopes, causing them to collapse their values back down into the 
                                // bucket's lookup.
                                // NOTE: this order is important because when we infer outputs, we are trying
                                // to produce the same results as would be produced from a full build; as such
                                // if we're doing both the infer and execute steps, we want the outputs from
                                // the execute step to override the outputs of the infer step -- this models
                                // the full build scenario more correctly than if the steps were reversed
                                entryForInference.LeaveScope();
                                entryForInference = null;
                                entryForExecution.LeaveScope();
                                entryForExecution = null;
                                targetSuccess = (bucketResult != null) && (bucketResult.ResultCode == WorkUnitResultCode.Success);
                                break;

                            case DependencyAnalysisResult.SkipNoInputs:
                            case DependencyAnalysisResult.SkipNoOutputs:
                                // We have either no inputs or no outputs, so there is nothing to do.
                                targetSuccess = true;
                                break;
                        }
                    }
                    catch (InvalidProjectFileException e)
                    {
                        // Make sure the Invalid Project error gets logged *before* TargetFinished.  Otherwise,
                        // the log is confusing.
                        targetLoggingContext.LogInvalidProjectFileError(e);

                        if (null != entryForInference)
                        {
                            entryForInference.LeaveScope();
                        }

                        if (null != entryForExecution)
                        {
                            entryForExecution.LeaveScope();
                        }

                        aggregateResult = aggregateResult.AggregateResult(new WorkUnitResult(WorkUnitResultCode.Failed, WorkUnitActionCode.Stop, null));
                    }
                    finally
                    {
                        // Don't log the last target finished event until we can process the target outputs as we want to attach them to the 
                        // last target batch.
                        if (targetLoggingContext != null && i < numberOfBuckets - 1)
                        {
                            targetLoggingContext.LogTargetBatchFinished(projectFullPath, targetSuccess, null);
                            targetLoggingContext = null;
                        }
                    }
                }

                // Produce the final results.
                List<TaskItem> targetOutputItems = new List<TaskItem>();

                try
                {
                    // If any legacy CallTarget operations took place, integrate them back in to the main lookup now.
                    LeaveLegacyCallTargetScopes();

                    // Publish the items for each bucket back into the baseLookup.  Note that EnterScope() was actually called on each
                    // bucket inside of the ItemBucket constructor, which is why you don't see it anywhere around here.
                    foreach (ItemBucket bucket in buckets)
                    {
                        bucket.LeaveScope();
                    }

                    string targetReturns = _target.Returns;
                    ElementLocation targetReturnsLocation = _target.ReturnsLocation;

                    // If there are no targets in the project file that use the "Returns" attribute, that means that we 
                    // revert to the legacy behavior in the case where Returns is not specified (null, rather
                    // than the empty string, which indicates no returns).  Legacy behavior is for all 
                    // of the target's Outputs to be returned. 
                    // On the other hand, if there is at least one target in the file that uses the Returns attribute, 
                    // then all targets in the file are run according to the new behaviour (return nothing unless otherwise
                    // specified by the Returns attribute). 
                    if (targetReturns == null)
                    {
                        if (!_target.ParentProjectSupportsReturnsAttribute)
                        {
                            targetReturns = _target.Outputs;
                            targetReturnsLocation = _target.OutputsLocation;
                        }
                    }

                    if (!String.IsNullOrEmpty(targetReturns))
                    {
                        // Determine if we should keep duplicates.
                        bool keepDupes = ConditionEvaluator.EvaluateCondition
                                 (
                                 _target.KeepDuplicateOutputs,
                                 ParserOptions.AllowPropertiesAndItemLists,
                                 _expander,
                                 ExpanderOptions.ExpandPropertiesAndItems,
                                 requestEntry.ProjectRootDirectory,
                                 _target.KeepDuplicateOutputsLocation,
                                 projectLoggingContext.LoggingService,
                                 projectLoggingContext.BuildEventContext
                                 );

                        // NOTE: we need to gather the outputs in batches, because the output specification may reference item metadata
                        // Also, we are using the baseLookup, which has possibly had changes made to it since the project started.  Because of this, the
                        // set of outputs calculated here may differ from those which would have been calculated at the beginning of the target.  It is 
                        // assumed the user intended this.
                        List<ItemBucket> batchingBuckets = BatchingEngine.PrepareBatchingBuckets(GetBatchableParametersForTarget(), _baseLookup, _target.Location);

                        if (keepDupes)
                        {
                            foreach (ItemBucket bucket in batchingBuckets)
                            {
                                targetOutputItems.AddRange(bucket.Expander.ExpandIntoTaskItemsLeaveEscaped(targetReturns, ExpanderOptions.ExpandAll, targetReturnsLocation));
                            }
                        }
                        else
                        {
                            HashSet<TaskItem> addedItems = new HashSet<TaskItem>();
                            foreach (ItemBucket bucket in batchingBuckets)
                            {
                                IList<TaskItem> itemsToAdd = bucket.Expander.ExpandIntoTaskItemsLeaveEscaped(targetReturns, ExpanderOptions.ExpandAll, targetReturnsLocation);

                                foreach (TaskItem item in itemsToAdd)
                                {
                                    if (!addedItems.Contains(item))
                                    {
                                        targetOutputItems.Add(item);
                                        addedItems.Add(item);
                                    }
                                }
                            }
                        }
                    }
                }
                finally
                {
                    if (targetLoggingContext != null)
                    {
                        // log the last target finished since we now have the target outputs. 
                        targetLoggingContext.LogTargetBatchFinished(projectFullPath, targetSuccess, targetOutputItems != null && targetOutputItems.Count > 0 ? targetOutputItems : null);
                    }
                }

                _targetResult = new TargetResult(targetOutputItems.ToArray(), aggregateResult);

                if (aggregateResult.ResultCode == WorkUnitResultCode.Failed && aggregateResult.ActionCode == WorkUnitActionCode.Stop)
                {
                    _state = TargetEntryState.ErrorExecution;
                }
                else
                {
                    _state = TargetEntryState.Completed;
                }
            }
            finally
            {
                _isExecuting = false;
            }
#if MSBUILDENABLEVSPROFILING 
            }
            finally
            {
                string endTargetBuild = String.Format(CultureInfo.CurrentCulture, "Build Target {0} in Project {1} - End", this.Name, projectFullPath);
                DataCollection.CommentMarkProfile(8801, endTargetBuild);
            }
#endif
        }