mcs/class/Microsoft.Build/Microsoft.Build.Internal/BuildEngine4.cs

   1 //
   2 // BuildEngine4.cs
   3 //
   4 // Author:
   5 //   Atsushi Enomoto (atsushi@xamarin.com)
   6 //
   7 // Copyright (C) 2013 Xamarin Inc. (http://www.xamarin.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28 using System;
  29 using System.Collections;
  30 using System.Collections.Generic;
  31 using Microsoft.Build.Execution;
  32 using Microsoft.Build.Framework;
  33 using Microsoft.Build.Evaluation;
  34 using System.Linq;
  35 using System.IO;
  36 using Microsoft.Build.Exceptions;
  37 using System.Globalization;
  38 using Microsoft.Build.Construction;
  39 using Microsoft.Build.Internal.Expressions;
  40
  41 namespace Microsoft.Build.Internal
  42 {
  43         class BuildEngine4
  44 #if NET_4_5
  45                 : IBuildEngine4
  46 #else
  47                 : IBuildEngine3
  48 #endif
  49         {
  50                 public BuildEngine4 (BuildSubmission submission)
  51                 {
  52                         this.submission = submission;
  53                         event_source = new Microsoft.Build.BuildEngine.EventSource ();
  54                         if (submission.BuildManager.OngoingBuildParameters.Loggers != null)
  55                                 foreach (var l in submission.BuildManager.OngoingBuildParameters.Loggers)
  56                                         l.Initialize (event_source);
  57                 }
  58
  59                 BuildSubmission submission;
  60                 ProjectInstance project;
  61                 ProjectTaskInstance current_task;
  62                 Microsoft.Build.BuildEngine.EventSource event_source;
  63
  64                 public ProjectCollection Projects {
  65                         get { return submission.BuildManager.OngoingBuildParameters.ProjectCollection; }
  66                 }
  67
  68                 // FIXME:
  69                 // While we are not faced to implement those features, there are some modern task execution requirements.
  70                 //
  71                 // This will have to be available for "out of process" nodes (see NodeAffinity).
  72                 // NodeAffinity is set per project file at BuildManager.HostServices.
  73                 // When NodeAffinity is set to OutOfProc, it should probably launch different build host
  74                 // that runs separate build tasks. (.NET has MSBuildTaskHost.exe which I guess is about that.)
  75                 //
  76                 // Also note that the complete implementation has to support LoadInSeparateAppDomainAttribute
  77                 // (which is most likely derived from AppDomainIsolatedBuildTask) that marks a task to run
  78                 // in separate AppDomain.
  79                 //
  80                 public void BuildProject (Func<bool> checkCancel, BuildResult result, ProjectInstance project, IEnumerable<string> targetNames, IDictionary<string,string> globalProperties, IDictionary<string,string> targetOutputs, string toolsVersion)
  81                 {
  82                         if (toolsVersion == null)
  83                                 throw new ArgumentNullException ("toolsVersion");
  84
  85                         var parameters = submission.BuildManager.OngoingBuildParameters;
  86                         var toolset = parameters.GetToolset (toolsVersion);
  87                         if (toolset == null)
  88                                 throw new InvalidOperationException (string.Format ("Toolset version '{0}' was not resolved to valid toolset", toolsVersion));
  89                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Using Toolset version {0}.", toolsVersion), null, null, MessageImportance.Low));
  90                         var buildTaskFactory = new BuildTaskFactory (BuildTaskDatabase.GetDefaultTaskDatabase (toolset), new BuildTaskDatabase (this, submission.BuildRequest.ProjectInstance));
  91                         BuildProject (new InternalBuildArguments () { CheckCancel = checkCancel, Result = result, Project = project, TargetNames = targetNames, GlobalProperties = globalProperties, TargetOutputs = targetOutputs, ToolsVersion = toolsVersion, BuildTaskFactory = buildTaskFactory });
  92                 }
  93
  94                 class InternalBuildArguments
  95                 {
  96                         public Func<bool> CheckCancel;
  97                         public BuildResult Result;
  98                         public ProjectInstance Project;
  99                         public IEnumerable<string> TargetNames;
 100                         public IDictionary<string,string> GlobalProperties;
 101                         public IDictionary<string,string> TargetOutputs;
 102                         public string ToolsVersion;
 103                         public BuildTaskFactory BuildTaskFactory;
 104
 105                         public void AddTargetResult (string targetName, TargetResult targetResult)
 106                         {
 107                                 if (!Result.HasResultsForTarget (targetName))
 108                                         Result.AddResultsForTarget (targetName, targetResult);
 109                         }
 110                 }
 111
 112                 void BuildProject (InternalBuildArguments args)
 113                 {
 114                         var request = submission.BuildRequest;
 115                         var parameters = submission.BuildManager.OngoingBuildParameters;
 116                         this.project = args.Project;
 117
 118                         string directoryBackup = Directory.GetCurrentDirectory ();
 119                         Directory.SetCurrentDirectory (project.Directory);
 120                         event_source.FireBuildStarted (this, new BuildStartedEventArgs ("Build Started", null, DateTime.Now));
 121
 122                         try {
 123
 124                                 var initialPropertiesFormatted = "Initial Properties:\n" + string.Join (Environment.NewLine, project.Properties.OrderBy (p => p.Name).Select (p => string.Format ("{0} = {1}", p.Name, p.EvaluatedValue)).ToArray ());
 125                                 LogMessageEvent (new BuildMessageEventArgs (initialPropertiesFormatted, null, null, MessageImportance.Low));
 126                                 var initialItemsFormatted = "Initial Items:\n" + string.Join (Environment.NewLine, project.Items.OrderBy (i => i.ItemType).Select (i => string.Format ("{0} : {1}", i.ItemType, i.EvaluatedInclude)).ToArray ());
 127                                 LogMessageEvent (new BuildMessageEventArgs (initialItemsFormatted, null, null, MessageImportance.Low));
 128
 129                                 // null targets -> success. empty targets -> success(!)
 130                                 if (request.TargetNames == null)
 131                                         args.Result.OverallResult = BuildResultCode.Success;
 132                                 else {
 133                                         foreach (var targetName in (args.TargetNames ?? request.TargetNames).Where (t => t != null))
 134                                                 BuildTargetByName (targetName, args);
 135
 136                                         // FIXME: check .NET behavior, whether cancellation always results in failure.
 137                                         args.Result.OverallResult = args.CheckCancel () ? BuildResultCode.Failure : args.Result.ResultsByTarget.Any (p => p.Value.ResultCode == TargetResultCode.Failure) ? BuildResultCode.Failure : BuildResultCode.Success;
 138                                 }
 139                         } catch (Exception ex) {
 140                                 args.Result.OverallResult = BuildResultCode.Failure;
 141                                 LogErrorEvent (new BuildErrorEventArgs (null, null, project.FullPath, 0, 0, 0, 0, "Unhandled exception occured during a build", null, null));
 142                                 LogMessageEvent (new BuildMessageEventArgs ("Exception details: " + ex, null, null, MessageImportance.Low));
 143                                 throw; // BuildSubmission re-catches this.
 144                         } finally {
 145                                 event_source.FireBuildFinished (this, new BuildFinishedEventArgs ("Build Finished.", null, args.Result.OverallResult == BuildResultCode.Success, DateTime.Now));
 146                                 Directory.SetCurrentDirectory (directoryBackup);
 147                         }
 148                 }
 149
 150                 bool BuildTargetByName (string targetName, InternalBuildArguments args)
 151                 {
 152                         var request = submission.BuildRequest;
 153                         var parameters = submission.BuildManager.OngoingBuildParameters;
 154                         ProjectTargetInstance target;
 155                         TargetResult dummyResult;
 156
 157                         if (args.Result.ResultsByTarget.TryGetValue (targetName, out dummyResult) && dummyResult.ResultCode == TargetResultCode.Success) {
 158                                 LogMessageEvent (new BuildMessageEventArgs (string.Format ("Target '{0}' was skipped because it was already built successfully.", targetName), null, null, MessageImportance.Low));
 159                                 return true; // do not add result.
 160                         }
 161
 162                         var targetResult = new TargetResult ();
 163
 164                         // null key is allowed and regarded as blind success(!) (as long as it could retrieve target)
 165                         if (!request.ProjectInstance.Targets.TryGetValue (targetName, out target))
 166                                 // FIXME: from MSBuild.exe it is given MSB4057. Can we assign a number too?
 167                                 throw new InvalidOperationException (string.Format ("target '{0}' was not found in project '{1}'", targetName, project.FullPath));
 168                         else if (!args.Project.EvaluateCondition (target.Condition)) {
 169                                 LogMessageEvent (new BuildMessageEventArgs (string.Format ("Target '{0}' was skipped because condition '{1}' was not met.", target.Name, target.Condition), null, null, MessageImportance.Low));
 170                                 targetResult.Skip ();
 171                         } else {
 172                                 // process DependsOnTargets first.
 173                                 foreach (var dep in project.ExpandString (target.DependsOnTargets).Split (';').Select (s => s.Trim ()).Where (s => !string.IsNullOrEmpty (s))) {
 174                                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Target '{0}' depends on '{1}'.", target.Name, dep), null, null, MessageImportance.Low));
 175                                         if (!BuildTargetByName (dep, args)) {
 176                                                 LogMessageEvent (new BuildMessageEventArgs (string.Format ("Quit target '{0}', as dependency target '{1}' has failed.", target.Name, dep), null, null, MessageImportance.Low));
 177                                                 return false;
 178                                         }
 179                                 }
 180
 181                                 Func<string,ITaskItem> creator = s => new TargetOutputTaskItem () { ItemSpec = s };
 182
 183                                 event_source.FireTargetStarted (this, new TargetStartedEventArgs ("Target Started", null, target.Name, project.FullPath, target.FullPath));
 184                                 try {
 185                                         // FIXME: examine in which scenario Inputs/Outputs inconsistency results in errors. Now it rather prevents csproj build.
 186                                         /*if (!string.IsNullOrEmpty (target.Inputs) != !string.IsNullOrEmpty (target.Outputs)) {
 187                                                 targetResult.Failure (new InvalidProjectFileException (target.Location, null, string.Format ("Target {0} has mismatching Inputs and Outputs specification. When one is specified, another one has to be specified too.", targetName), null, null, null));
 188                                         } else*/ {
 189                                                 bool skip = false;
 190                                                 if (!string.IsNullOrEmpty (target.Inputs)) {
 191                                                         var inputs = args.Project.GetAllItems (target.Inputs, string.Empty, creator, creator, s => true, (t, s) => {
 192                                                         });
 193                                                         if (!inputs.Any ()) {
 194                                                                 LogMessageEvent (new BuildMessageEventArgs (string.Format ("Target '{0}' was skipped because there is no input.", target.Name), null, null, MessageImportance.Low));
 195                                                                 skip = true;
 196                                                         } else {
 197                                                                 var outputs = args.Project.GetAllItems (target.Outputs, string.Empty, creator, creator, s => true, (t, s) => {
 198                                                                 });
 199                                                                 var needsUpdates = GetOlderOutputsThanInputs (inputs, outputs).FirstOrDefault ();
 200                                                                 if (needsUpdates != null)
 201                                                                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Target '{0}' needs to be built because new output {1} is needed.", target.Name, needsUpdates.ItemSpec), null, null, MessageImportance.Low));
 202                                                                 else {
 203                                                                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Target '{0}' was skipped because all the outputs are newer than all the inputs.", target.Name), null, null, MessageImportance.Low));
 204                                                                         skip = true;
 205                                                                 }
 206                                                         }
 207                                                 }
 208                                                 if (skip) {
 209                                                         targetResult.Skip ();
 210                                                 } else {
 211                                                         if (DoBuildTarget (target, targetResult, args)) {
 212                                                                 var items = args.Project.GetAllItems (target.Outputs, string.Empty, creator, creator, s => true, (t, s) => {
 213                                                                 });
 214                                                                 targetResult.Success (items);
 215                                                         }
 216                                                 }
 217                                         }
 218                                 } finally {
 219                                         event_source.FireTargetFinished (this, new TargetFinishedEventArgs ("Target Finished", null, targetName, project.FullPath, target.FullPath, targetResult.ResultCode != TargetResultCode.Failure));
 220                                 }
 221                         }
 222                         args.AddTargetResult (targetName, targetResult);
 223
 224                         return targetResult.ResultCode != TargetResultCode.Failure;
 225                 }
 226
 227                 IEnumerable<ITaskItem> GetOlderOutputsThanInputs (IEnumerable<ITaskItem> inputs, IEnumerable<ITaskItem> outputs)
 228                 {
 229                         return outputs.Where (o => !File.Exists (o.GetMetadata ("FullPath")) || inputs.Any (i => string.CompareOrdinal (i.GetMetadata ("LastModifiedTime"), o.GetMetadata ("LastModifiedTime")) > 0));
 230                 }
 231
 232                 // FIXME: Exception should be caught at caller site.
 233                 bool DoBuildTarget (ProjectTargetInstance target, TargetResult targetResult, InternalBuildArguments args)
 234                 {
 235                         var request = submission.BuildRequest;
 236
 237                         // Here we check cancellation (only after TargetStarted event).
 238                         if (args.CheckCancel ()) {
 239                                 targetResult.Failure (new BuildAbortedException ("Build has canceled"));
 240                                 return false;
 241                         }
 242
 243                         try {
 244                                 foreach (var child in target.Children) {
 245                                         // Evaluate additional target properties
 246                                         var tp = child as ProjectPropertyGroupTaskInstance;
 247                                         if (tp != null) {
 248                                                 if (!args.Project.EvaluateCondition (tp.Condition))
 249                                                         continue;
 250                                                 foreach (var p in tp.Properties) {
 251                                                         if (!args.Project.EvaluateCondition (p.Condition))
 252                                                                 continue;
 253                                                         var value = args.Project.ExpandString (p.Value);
 254                                                         project.SetProperty (p.Name, value);
 255                                                 }
 256                                         }
 257
 258                                         var ii = child as ProjectItemGroupTaskInstance;
 259                                         if (ii != null) {
 260                                                 if (!args.Project.EvaluateCondition (ii.Condition))
 261                                                         continue;
 262                                                 foreach (var item in ii.Items) {
 263                                                         if (!args.Project.EvaluateCondition (item.Condition))
 264                                                                 continue;
 265                                                         project.AddItem (item.ItemType, project.ExpandString (item.Include));
 266                                                 }
 267                                         }
 268
 269                                         var task = child as ProjectTaskInstance;
 270                                         if (task != null) {
 271                                                 current_task = task;
 272                                                 if (!args.Project.EvaluateCondition (task.Condition)) {
 273                                                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Task '{0}' was skipped because condition '{1}' wasn't met.", task.Name, task.Condition), null, null, MessageImportance.Low));
 274                                                         continue;
 275                                                 }
 276                                                 if (!RunBuildTask (target, task, targetResult, args))
 277                                                         return false;
 278                                         }
 279                                 }
 280                         } catch (Exception ex) {
 281                                 // fallback task specified by OnError element
 282                                 foreach (var c in target.Children.OfType<ProjectOnErrorInstance> ()) {
 283                                         if (!args.Project.EvaluateCondition (c.Condition))
 284                                                 continue;
 285                                         foreach (var fallbackTarget in project.ExpandString (c.ExecuteTargets).Split (';'))
 286                                                 BuildTargetByName (fallbackTarget, args);
 287                                 }
 288                                 int line = target.Location != null ? target.Location.Line : 0;
 289                                 int col = target.Location != null ? target.Location.Column : 0;
 290                                 LogErrorEvent (new BuildErrorEventArgs (null, null, target.FullPath, line, col, 0, 0, ex.Message, null, null));
 291                                 targetResult.Failure (ex);
 292                                 return false;
 293                         }
 294                         return true;
 295                 }
 296
 297                 bool RunBuildTask (ProjectTargetInstance target, ProjectTaskInstance taskInstance, TargetResult targetResult, InternalBuildArguments args)
 298                 {
 299                         var request = submission.BuildRequest;
 300
 301                         var host = request.HostServices == null ? null : request.HostServices.GetHostObject (request.ProjectFullPath, target.Name, taskInstance.Name);
 302
 303                         // Create Task instance.
 304                         var factoryIdentityParameters = new Dictionary<string,string> ();
 305                         #if NET_4_5
 306                         factoryIdentityParameters ["MSBuildRuntime"] = taskInstance.MSBuildRuntime;
 307                         factoryIdentityParameters ["MSBuildArchitecture"] = taskInstance.MSBuildArchitecture;
 308                         #endif
 309                         var task = args.BuildTaskFactory.CreateTask (taskInstance.Name, factoryIdentityParameters, this);
 310                         if (task == null)
 311                                 throw new InvalidOperationException (string.Format ("TaskFactory {0} returned null Task", args.BuildTaskFactory));
 312                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Using task {0} from {1}", taskInstance.Name, task.GetType ()), null, null, MessageImportance.Low));
 313                         task.HostObject = host;
 314                         task.BuildEngine = this;
 315
 316                         // Prepare task parameters.
 317                         var evaluator = new ExpressionEvaluator (project);
 318                         var evaluatedTaskParams = taskInstance.Parameters.Select (p => new KeyValuePair<string,string> (p.Key, project.ExpandString (evaluator, p.Value)));
 319
 320                         var requiredProps = task.GetType ().GetProperties ()
 321                                 .Where (p => p.CanWrite && p.GetCustomAttributes (typeof (RequiredAttribute), true).Any ());
 322                         var missings = requiredProps.Where (p => !evaluatedTaskParams.Any (tp => tp.Key.Equals (p.Name, StringComparison.OrdinalIgnoreCase)));
 323                         if (missings.Any ())
 324                                 throw new InvalidOperationException (string.Format ("Task {0} of type {1} is used without specifying mandatory property: {2}",
 325                                         taskInstance.Name, task.GetType (), string.Join (", ", missings.Select (p => p.Name).ToArray ())));
 326
 327                         foreach (var p in evaluatedTaskParams) {
 328                                 switch (p.Key.ToLower ()) {
 329                                 case "condition":
 330                                 case "continueonerror":
 331                                         continue;
 332                                 }
 333                                 var prop = task.GetType ().GetProperty (p.Key);
 334                                 if (prop == null)
 335                                         throw new InvalidOperationException (string.Format ("Task {0} does not have property {1}", taskInstance.Name, p.Key));
 336                                 if (!prop.CanWrite)
 337                                         throw new InvalidOperationException (string.Format ("Task {0} has property {1} but it is read-only.", taskInstance.Name, p.Key));
 338                                 if (string.IsNullOrEmpty (p.Value) && !requiredProps.Contains (prop))
 339                                         continue;
 340                                 try {
 341                                         prop.SetValue (task, ConvertTo (p.Value, prop.PropertyType, evaluator), null);
 342                                 } catch (Exception ex) {
 343                                         throw new InvalidOperationException (string.Format ("Failed to convert '{0}' for property '{1}' of type {2}", p.Value, prop.Name, prop.PropertyType), ex);
 344                                 }
 345                         }
 346
 347                         // Do execute task.
 348                         bool taskSuccess = false;
 349                         event_source.FireTaskStarted (this, new TaskStartedEventArgs ("Task Started", null, project.FullPath, taskInstance.FullPath, taskInstance.Name));
 350                         try {
 351                                 taskSuccess = task.Execute ();
 352
 353                                 if (!taskSuccess) {
 354                                         targetResult.Failure (null);
 355                                         if (!ContinueOnError) {
 356                                                 return false;
 357                                         }
 358                                 } else {
 359                                         // Evaluate task output properties and items.
 360                                         foreach (var to in taskInstance.Outputs) {
 361                                                 if (!project.EvaluateCondition (to.Condition))
 362                                                         continue;
 363                                                 var toItem = to as ProjectTaskOutputItemInstance;
 364                                                 var toProp = to as ProjectTaskOutputPropertyInstance;
 365                                                 string taskParameter = toItem != null ? toItem.TaskParameter : toProp.TaskParameter;
 366                                                 var pi = task.GetType ().GetProperty (taskParameter);
 367                                                 if (pi == null)
 368                                                         throw new InvalidOperationException (string.Format ("Task {0} does not have property {1} specified as TaskParameter", taskInstance.Name, toItem.TaskParameter));
 369                                                 if (!pi.CanRead)
 370                                                         throw new InvalidOperationException (string.Format ("Task {0} has property {1} specified as TaskParameter, but it is write-only", taskInstance.Name, toItem.TaskParameter));
 371                                                 var value = pi.GetValue (task, null);
 372                                                 var valueString = ConvertFrom (value);
 373                                                 if (toItem != null) {
 374                                                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Output Item {0} from TaskParameter {1}: {2}", toItem.ItemType, toItem.TaskParameter, valueString), null, null, MessageImportance.Low));
 375                                                         Action<ITaskItem> addItem = i => {
 376                                                                 var metadata = new ArrayList (i.MetadataNames).ToArray ().Cast<string> ().Select (n => new KeyValuePair<string,string> (n, i.GetMetadata (n)));
 377                                                                 args.Project.AddItem (toItem.ItemType, i.ItemSpec, metadata);
 378                                                         };
 379                                                         var taskItemArray = value as ITaskItem [];
 380                                                         if (taskItemArray != null) {
 381                                                                 foreach (var ti in taskItemArray)
 382                                                                         addItem (ti);
 383                                                         } else {
 384                                                                 var taskItem = value as ITaskItem;
 385                                                                 if (taskItem != null)
 386                                                                         addItem (taskItem);
 387                                                                 else
 388                                                                         foreach (var item in valueString.Split (';'))
 389                                                                                 args.Project.AddItem (toItem.ItemType, item);
 390                                                         }
 391                                                 } else {
 392                                                         LogMessageEvent (new BuildMessageEventArgs (string.Format ("Output Property {0} from TaskParameter {1}: {2}", toProp.PropertyName, toProp.TaskParameter, valueString), null, null, MessageImportance.Low));
 393                                                         args.Project.SetProperty (toProp.PropertyName, valueString);
 394                                                 }
 395                                         }
 396                                 }
 397                         } finally {
 398                                 event_source.FireTaskFinished (this, new TaskFinishedEventArgs ("Task Finished", null, project.FullPath, taskInstance.FullPath, taskInstance.Name, taskSuccess));
 399                         }
 400                         return true;
 401                 }
 402
 403                 object ConvertTo (string source, Type targetType, ExpressionEvaluator evaluator)
 404                 {
 405                         if (targetType == typeof (ITaskItem) || targetType.IsSubclassOf (typeof (ITaskItem))) {
 406                                 var item = evaluator.EvaluatedTaskItems.FirstOrDefault (i => string.Equals (i.ItemSpec, source.Trim (), StringComparison.OrdinalIgnoreCase));
 407                                 var ret = new TargetOutputTaskItem () { ItemSpec = source.Trim () };
 408                                 if (item != null)
 409                                         foreach (string name in item.MetadataNames)
 410                                                 ret.SetMetadata (name, item.GetMetadata (name));
 411                                 return ret;
 412                         }
 413                         if (targetType.IsArray)
 414                                 return new ArrayList (source.Split (';').Select (s => s.Trim ()).Where (s => !string.IsNullOrEmpty (s)).Select (s => ConvertTo (s, targetType.GetElementType (), evaluator)).ToArray ())
 415                                                 .ToArray (targetType.GetElementType ());
 416                         if (targetType == typeof (bool)) {
 417                                 switch (source != null ? source.ToLower (CultureInfo.InvariantCulture) : string.Empty) {
 418                                 case "true":
 419                                 case "yes":
 420                                 case "on":
 421                                         return true;
 422                                 case "false":
 423                                 case "no":
 424                                 case "off":
 425                                 case "":
 426                                         return false;
 427                                 }
 428                         }
 429                         return Convert.ChangeType (source == "" ? null : source, targetType);
 430                 }
 431
 432                 string ConvertFrom (object source)
 433                 {
 434                         if (source == null)
 435                                 return string.Empty;
 436                         if (source is ITaskItem)
 437                                 return ((ITaskItem) source).ItemSpec;
 438                         if (source.GetType ().IsArray)
 439                                 return string.Join (";", ((Array) source).Cast<object> ().Select (o => ConvertFrom (o)).ToArray ());
 440                         else
 441                                 return (string) Convert.ChangeType (source, typeof (string));
 442                 }
 443
 444                 class TargetOutputTaskItem : ITaskItem2
 445                 {
 446                         Hashtable metadata = new Hashtable ();
 447
 448                         #region ITaskItem2 implementation
 449                         public string GetMetadataValueEscaped (string metadataName)
 450                         {
 451                                 return ProjectCollection.Escape ((string) metadata [metadataName]);
 452                         }
 453                         public void SetMetadataValueLiteral (string metadataName, string metadataValue)
 454                         {
 455                                 metadata [metadataName] = ProjectCollection.Unescape (metadataValue);
 456                         }
 457                         public IDictionary CloneCustomMetadataEscaped ()
 458                         {
 459                                 var ret = new Hashtable ();
 460                                 foreach (DictionaryEntry e in metadata)
 461                                         ret [e.Key] = ProjectCollection.Escape ((string) e.Value);
 462                                 return ret;
 463                         }
 464                         public string EvaluatedIncludeEscaped {
 465                                 get { return ProjectCollection.Escape (ItemSpec); }
 466                                 set { ItemSpec = ProjectCollection.Unescape (value); }
 467                         }
 468                         #endregion
 469                         #region ITaskItem implementation
 470                         public IDictionary CloneCustomMetadata ()
 471                         {
 472                                 return new Hashtable (metadata);
 473                         }
 474                         public void CopyMetadataTo (ITaskItem destinationItem)
 475                         {
 476                                 foreach (DictionaryEntry e in metadata)
 477                                         destinationItem.SetMetadata ((string) e.Key, (string) e.Value);
 478                         }
 479                         public string GetMetadata (string metadataName)
 480                         {
 481                                 var wk = ProjectCollection.GetWellKnownMetadata (metadataName, ItemSpec, Path.GetFullPath, null);
 482                                 if (wk != null)
 483                                         return wk;
 484                                 var ret = (string) metadata [metadataName];
 485                                 return ret ?? string.Empty;
 486                         }
 487                         public void RemoveMetadata (string metadataName)
 488                         {
 489                                 metadata.Remove (metadataName);
 490                         }
 491                         public void SetMetadata (string metadataName, string metadataValue)
 492                         {
 493                                 metadata [metadataName] = metadataValue;
 494                         }
 495                         public string ItemSpec { get; set; }
 496                         public int MetadataCount {
 497                                 get { return metadata.Count; }
 498                         }
 499                         public ICollection MetadataNames {
 500                                 get { return metadata.Keys; }
 501                         }
 502                         #endregion
 503
 504                         public override string ToString ()
 505                         {
 506                                 return ItemSpec;
 507                         }
 508                 }
 509
 510 #if NET_4_5
 511                 #region IBuildEngine4 implementation
 512
 513                 // task objects are not in use anyways though...
 514
 515                 class TaskObjectRegistration
 516                 {
 517                         public TaskObjectRegistration (object key, object obj, RegisteredTaskObjectLifetime lifetime, bool allowEarlyCollection)
 518                         {
 519                                 Key = key;
 520                                 Object = obj;
 521                                 Lifetime = lifetime;
 522                                 AllowEarlyCollection = allowEarlyCollection;
 523                         }
 524                         public object Key { get; private set; }
 525                         public object Object { get; private set; }
 526                         public RegisteredTaskObjectLifetime Lifetime { get; private set; }
 527                         public bool AllowEarlyCollection { get; private set; }
 528                 }
 529
 530                 List<TaskObjectRegistration> task_objects = new List<TaskObjectRegistration> ();
 531
 532                 public object GetRegisteredTaskObject (object key, RegisteredTaskObjectLifetime lifetime)
 533                 {
 534                         var reg = task_objects.FirstOrDefault (t => t.Key == key && t.Lifetime == lifetime);
 535                         return reg != null ? reg.Object : null;
 536                 }
 537
 538                 public void RegisterTaskObject (object key, object obj, RegisteredTaskObjectLifetime lifetime, bool allowEarlyCollection)
 539                 {
 540                         task_objects.Add (new TaskObjectRegistration (key, obj, lifetime, allowEarlyCollection));
 541                 }
 542
 543                 public object UnregisterTaskObject (object key, RegisteredTaskObjectLifetime lifetime)
 544                 {
 545                         var reg = task_objects.FirstOrDefault (t => t.Key == key && t.Lifetime == lifetime);
 546                         if (reg != null)
 547                                 task_objects.Remove (reg);
 548                         return reg.Object;
 549                 }
 550                 #endregion
 551 #endif
 552
 553                 #region IBuildEngine3 implementation
 554
 555                 public BuildEngineResult BuildProjectFilesInParallel (string[] projectFileNames, string[] targetNames, IDictionary[] globalProperties, IList<string>[] removeGlobalProperties, string[] toolsVersion, bool returnTargetOutputs)
 556                 {
 557                         throw new NotImplementedException ();
 558                 }
 559
 560                 public void Reacquire ()
 561                 {
 562                         throw new NotImplementedException ();
 563                 }
 564
 565                 public void Yield ()
 566                 {
 567                         throw new NotImplementedException ();
 568                 }
 569
 570                 #endregion
 571
 572                 #region IBuildEngine2 implementation
 573
 574                 // To NOT reuse this IBuildEngine instance for different build, we create another BuildManager and BuildSubmisson and then run it.
 575                 public bool BuildProjectFile (string projectFileName, string[] targetNames, IDictionary globalProperties, IDictionary targetOutputs, string toolsVersion)
 576                 {
 577                         var globalPropertiesThatMakeSense = new Dictionary<string,string> ();
 578                         foreach (DictionaryEntry p in globalProperties)
 579                                 globalPropertiesThatMakeSense [(string) p.Key] = (string) p.Value;
 580                         var result = new BuildManager ().Build (this.submission.BuildManager.OngoingBuildParameters.Clone (), new BuildRequestData (projectFileName, globalPropertiesThatMakeSense, toolsVersion, targetNames, null));
 581                         foreach (var p in result.ResultsByTarget)
 582                                 targetOutputs [p.Key] = p.Value.Items;
 583                         return result.OverallResult == BuildResultCode.Success;
 584                 }
 585
 586                 public bool BuildProjectFilesInParallel (string[] projectFileNames, string[] targetNames, IDictionary[] globalProperties, IDictionary[] targetOutputsPerProject, string[] toolsVersion, bool useResultsCache, bool unloadProjectsOnCompletion)
 587                 {
 588                         throw new NotImplementedException ();
 589                 }
 590
 591                 public bool IsRunningMultipleNodes {
 592                         get {
 593                                 throw new NotImplementedException ();
 594                         }
 595                 }
 596
 597                 ProjectInstance GetProjectInstance (string projectFileName, string toolsVersion)
 598                 {
 599                         string fullPath = Path.GetFullPath (projectFileName);
 600                         if (submission.BuildRequest.ProjectFullPath == fullPath)
 601                                 return submission.BuildRequest.ProjectInstance;
 602                         // FIXME: could also be filtered by global properties
 603                         // http://msdn.microsoft.com/en-us/library/microsoft.build.evaluation.projectcollection.getloadedprojects.aspx
 604                         var project = Projects.GetLoadedProjects (projectFileName).FirstOrDefault (p => p.ToolsVersion == toolsVersion);
 605                         if (project == null)
 606                                 throw new InvalidOperationException (string.Format ("Project '{0}' is not loaded", projectFileName));
 607                         return submission.BuildManager.GetProjectInstanceForBuild (project);
 608                 }
 609
 610                 #endregion
 611
 612                 #region IBuildEngine implementation
 613
 614                 public bool BuildProjectFile (string projectFileName, string[] targetNames, IDictionary globalProperties, IDictionary targetOutputs)
 615                 {
 616                         return BuildProjectFile (projectFileName, targetNames, globalProperties, targetOutputs, Projects.DefaultToolsVersion);
 617                 }
 618
 619                 public void LogCustomEvent (CustomBuildEventArgs e)
 620                 {
 621                         event_source.FireCustomEventRaised (this, e);
 622                 }
 623
 624                 public void LogErrorEvent (BuildErrorEventArgs e)
 625                 {
 626                         event_source.FireErrorRaised (this, e);
 627                 }
 628
 629                 public void LogMessageEvent (BuildMessageEventArgs e)
 630                 {
 631                         event_source.FireMessageRaised (this, e);
 632                 }
 633
 634                 public void LogWarningEvent (BuildWarningEventArgs e)
 635                 {
 636                         event_source.FireWarningRaised (this, e);
 637                 }
 638
 639                 public int ColumnNumberOfTaskNode {
 640                         get { return current_task.Location != null ? current_task.Location.Column : 0; }
 641                 }
 642
 643                 public bool ContinueOnError {
 644                         get { return current_task != null && project.EvaluateCondition (current_task.Condition) && EvaluateContinueOnError (current_task.ContinueOnError); }
 645                 }
 646
 647                 bool EvaluateContinueOnError (string value)
 648                 {
 649                         switch (value) {
 650                         case "WarnAndContinue":
 651                         case "ErrorAndContinue":
 652                                 return true;
 653                         case "ErrorAndStop":
 654                                 return false;
 655                         }
 656                         // empty means "stop on error", so don't pass empty string to EvaluateCondition().
 657                         return !string.IsNullOrEmpty (value) && project.EvaluateCondition (value);
 658                 }
 659
 660                 public int LineNumberOfTaskNode {
 661                         get { return current_task.Location != null ? current_task.Location.Line : 0; }
 662                 }
 663
 664                 public string ProjectFileOfTaskNode {
 665                         get { return current_task.FullPath; }
 666                 }
 667
 668                 #endregion
 669         }
 670 }
 671