Refactor project snapshot manager

Splits the 'trigger' out from the change manager. The next change will
add more functionality to DPSMBase.

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DefaultProjectSnapshotManager.cs

@@ -3,49 +3,43 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.Linq;
 
 namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
 {
-    internal class DefaultProjectSnapshotManager : ProjectSnapshotManager
+    internal class DefaultProjectSnapshotManager : ProjectSnapshotManagerBase
     {
-        private readonly Workspace _workspace;
+        private readonly ProjectSnapshotChangeTrigger[] _triggers;
         private readonly Dictionary<ProjectId, ProjectSnapshot> _projects;
         private readonly List<WeakReference<DefaultProjectSnapshotListener>> _listeners;
 
-        public DefaultProjectSnapshotManager(Workspace workspace)
+        public DefaultProjectSnapshotManager(IEnumerable<ProjectSnapshotChangeTrigger> triggers, Workspace workspace)
         {
-            _workspace = workspace;
+            if (triggers == null)
+            {
+                throw new ArgumentNullException(nameof(triggers));
+            }
+
+            if (workspace == null)
+            {
+                throw new ArgumentNullException(nameof(workspace));
+            }
+
+            _triggers = triggers.ToArray();
+            Workspace = workspace;
 
             _projects = new Dictionary<ProjectId, ProjectSnapshot>();
             _listeners = new List<WeakReference<DefaultProjectSnapshotListener>>();
 
-            // Attaching the event handler inside before initialization prevents re-entrancy without
+            for (var i = 0; i < _triggers.Length; i++)
-            // losing any notifications.
+            {
-            _workspace.WorkspaceChanged += Workspace_WorkspaceChanged;
+                _triggers[i].Initialize(this);
-            InitializeSolution(_workspace.CurrentSolution);
+            }
         }
 
         public override IReadOnlyList<ProjectSnapshot> Projects => _projects.Values.ToArray();
 
-        public override ProjectSnapshot FindProject(string projectPath)
+        public override Workspace Workspace { get; }
-        {
-            if (projectPath == null)
-            {
-                throw new ArgumentNullException(nameof(projectPath));
-            }
-
-            foreach (var project in _projects.Values)
-            { 
-                if (string.Equals(projectPath, project.UnderlyingProject.FilePath, StringComparison.OrdinalIgnoreCase))
-                {
-                    return project;
-                }
-            }
-
-            return null;
-        }
 
         public override ProjectSnapshotListener Subscribe()
         {
@@ -55,23 +49,60 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
             return subscription;
         }
 
-        private void InitializeSolution(Solution solution)
+        public override void ProjectAdded(Project underlyingProject)
         {
-            Debug.Assert(solution != null);
+            if (underlyingProject == null)
+            {
+                throw new ArgumentNullException(nameof(underlyingProject));
+            }
 
+            var snapshot = new DefaultProjectSnapshot(underlyingProject);
+            _projects[underlyingProject.Id] = snapshot;
+
+            // We need to notify listeners about every project add.
+            NotifyListeners(new ProjectChangeEventArgs(snapshot, ProjectChangeKind.Added));
+        }
+
+        public override void ProjectChanged(Project underlyingProject)
+        {
+            if (underlyingProject == null)
+            {
+                throw new ArgumentNullException(nameof(underlyingProject));
+            }
+
+            // For now we don't have any state associated with the project so we can just construct a new snapshot.
+            var snapshot = new DefaultProjectSnapshot(underlyingProject);
+            _projects[underlyingProject.Id] = snapshot;
+
+            // There's no need to notify listeners about project changes because we don't have any state.
+            // This will change when we implement extensibility support.
+        }
+
+        public override void ProjectRemoved(Project underlyingProject)
+        {
+            if (underlyingProject == null)
+            {
+                throw new ArgumentNullException(nameof(underlyingProject));
+            }
+            
+            if (_projects.TryGetValue(underlyingProject.Id, out var snapshot))
+            {
+                _projects.Remove(underlyingProject.Id);
+
+                // We need to notify listeners about every project removal.
+                NotifyListeners(new ProjectChangeEventArgs(snapshot, ProjectChangeKind.Removed));
+            }
+        }
+
+        public override void ProjectsCleared()
+        {
             foreach (var kvp in _projects.ToArray())
             {
                 _projects.Remove(kvp.Key);
+
+                // We need to notify listeners about every project removal.
                 NotifyListeners(new ProjectChangeEventArgs(kvp.Value, ProjectChangeKind.Removed));
             }
-
-            foreach (var project in solution.Projects)
-            {
-                var projectState = new DefaultProjectSnapshot(project);
-                _projects[project.Id] = projectState;
-
-                NotifyListeners(new ProjectChangeEventArgs(projectState, ProjectChangeKind.Added));
-            }
         }
 
         private void NotifyListeners(ProjectChangeEventArgs e)
@@ -88,59 +119,5 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
                 }
             }
         }
-
-        // Internal for testing
-        internal void Workspace_WorkspaceChanged(object sender, WorkspaceChangeEventArgs e)
-        {
-            Project underlyingProject;
-            ProjectSnapshot snapshot;
-            switch (e.Kind)
-            {
-                case WorkspaceChangeKind.ProjectAdded:
-                    {
-                        underlyingProject = e.NewSolution.GetProject(e.ProjectId);
-                        Debug.Assert(underlyingProject != null);
-
-                        snapshot = new DefaultProjectSnapshot(underlyingProject);
-                        _projects[e.ProjectId] = snapshot;
-
-                        NotifyListeners(new ProjectChangeEventArgs(snapshot, ProjectChangeKind.Added));
-                        break;
-                    }
-
-                case WorkspaceChangeKind.ProjectChanged:
-                case WorkspaceChangeKind.ProjectReloaded:
-                    {
-                        underlyingProject = e.NewSolution.GetProject(e.ProjectId);
-                        Debug.Assert(underlyingProject != null);
-
-                        snapshot = new DefaultProjectSnapshot(underlyingProject);
-                        _projects[e.ProjectId] = snapshot;
-
-                        NotifyListeners(new ProjectChangeEventArgs(snapshot, ProjectChangeKind.Changed));
-                        break;
-                    }
-
-                case WorkspaceChangeKind.ProjectRemoved:
-                    {
-                        // We're being extra defensive here to avoid crashes.
-                        if (_projects.TryGetValue(e.ProjectId, out snapshot))
-                        {
-                            _projects.Remove(e.ProjectId);
-                            NotifyListeners(new ProjectChangeEventArgs(snapshot, ProjectChangeKind.Removed));
-                        }
-
-                        break;
-                    }
-
-                case WorkspaceChangeKind.SolutionAdded:
-                case WorkspaceChangeKind.SolutionChanged:
-                case WorkspaceChangeKind.SolutionCleared:
-                case WorkspaceChangeKind.SolutionReloaded:
-                case WorkspaceChangeKind.SolutionRemoved:
-                    InitializeSolution(e.NewSolution);
-                    break;
-            }
-        }
     }
 }

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DefaultProjectSnapshotManagerFactory.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Composition;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Host.Mef;
@@ -12,6 +13,14 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
     [ExportLanguageServiceFactory(typeof(ProjectSnapshotManager), RazorLanguage.Name)]
     internal class DefaultProjectSnapshotManagerFactory : ILanguageServiceFactory
     {
+        private readonly IEnumerable<ProjectSnapshotChangeTrigger> _triggers;
+
+        [ImportingConstructor]
+        public DefaultProjectSnapshotManagerFactory([ImportMany] IEnumerable<ProjectSnapshotChangeTrigger> triggers)
+        {
+            _triggers = triggers;
+        }
+
         public ILanguageService CreateLanguageService(HostLanguageServices languageServices)
         {
             if (languageServices == null)
@@ -19,7 +28,7 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
                 throw new ArgumentNullException(nameof(languageServices));
             }
 
-            return new DefaultProjectSnapshotManager(languageServices.WorkspaceServices.Workspace);
+            return new DefaultProjectSnapshotManager(_triggers, languageServices.WorkspaceServices.Workspace);
         }
     }
 }

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshotChangeTrigger.cs

@@ -0,0 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
+{
+    internal abstract class ProjectSnapshotChangeTrigger
+    {
+        public abstract void Initialize(ProjectSnapshotManagerBase projectManager);
+    }
+}

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshotManager.cs

@@ -10,8 +10,6 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
     {
         public abstract IReadOnlyList<ProjectSnapshot> Projects { get; }
 
-        public abstract ProjectSnapshot FindProject(string projectPath);
-
         public abstract ProjectSnapshotListener Subscribe();
     }
 }

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshotManagerBase.cs

@@ -0,0 +1,18 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
+{
+    internal abstract class ProjectSnapshotManagerBase : ProjectSnapshotManager
+    {
+        public abstract Workspace Workspace { get; }
+
+        public abstract void ProjectAdded(Project underlyingProject);
+
+        public abstract void ProjectChanged(Project underlyingProject);
+
+        public abstract void ProjectRemoved(Project underlyingProject);
+
+        public abstract void ProjectsCleared();
+    }
+}

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshotManagerExtensions.cs

@@ -0,0 +1,25 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
+{
+    internal static class ProjectSnapshotManagerExtensions
+    {
+        public static ProjectSnapshot GetProjectWithFilePath(this ProjectSnapshotManager snapshotManager, string filePath)
+        {
+            var projects = snapshotManager.Projects;
+            for (var i = 0; i< projects.Count; i++)
+            {
+                var project = projects[i];
+                if (string.Equals(filePath, project.UnderlyingProject.FilePath, StringComparison.OrdinalIgnoreCase))
+                {
+                    return project;
+                }
+            }
+
+            return null;
+        }
+    }
+}

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/WorkspaceProjectSnapshotChangeTrigger.cs

@@ -0,0 +1,78 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Composition;
+using System.Diagnostics;
+
+namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
+{
+    [Export(typeof(ProjectSnapshotChangeTrigger))]
+    internal class WorkspaceProjectSnapshotChangeTrigger : ProjectSnapshotChangeTrigger
+    {
+        private ProjectSnapshotManagerBase _projectManager;
+
+        public override void Initialize(ProjectSnapshotManagerBase projectManager)
+        {
+            _projectManager = projectManager;
+            _projectManager.Workspace.WorkspaceChanged += Workspace_WorkspaceChanged;
+
+            InitializeSolution(_projectManager.Workspace.CurrentSolution);
+        }
+
+        private void InitializeSolution(Solution solution)
+        {
+            Debug.Assert(solution != null);
+
+            _projectManager.ProjectsCleared();
+
+            foreach (var project in solution.Projects)
+            {
+                _projectManager.ProjectAdded(project);
+            }
+        }
+
+        // Internal for testing
+        internal void Workspace_WorkspaceChanged(object sender, WorkspaceChangeEventArgs e)
+        {
+            Project underlyingProject;
+            switch (e.Kind)
+            {
+                case WorkspaceChangeKind.ProjectAdded:
+                    {
+                        underlyingProject = e.NewSolution.GetProject(e.ProjectId);
+                        Debug.Assert(underlyingProject != null);
+
+                        _projectManager.ProjectAdded(underlyingProject);
+                        break;
+                    }
+
+                case WorkspaceChangeKind.ProjectChanged:
+                case WorkspaceChangeKind.ProjectReloaded:
+                    {
+                        underlyingProject = e.NewSolution.GetProject(e.ProjectId);
+                        Debug.Assert(underlyingProject != null);
+
+                        _projectManager.ProjectChanged(underlyingProject);
+                        break;
+                    }
+
+                case WorkspaceChangeKind.ProjectRemoved:
+                    {
+                        underlyingProject = e.OldSolution.GetProject(e.ProjectId);
+                        Debug.Assert(underlyingProject != null);
+
+                        _projectManager.ProjectRemoved(underlyingProject);
+                        break;
+                    }
+
+                case WorkspaceChangeKind.SolutionAdded:
+                case WorkspaceChangeKind.SolutionChanged:
+                case WorkspaceChangeKind.SolutionCleared:
+                case WorkspaceChangeKind.SolutionReloaded:
+                case WorkspaceChangeKind.SolutionRemoved:
+                    InitializeSolution(e.NewSolution);
+                    break;
+            }
+        }
+    }
+}

src/Microsoft.VisualStudio.LanguageServices.Razor/Editor/DefaultVisualStudioDocumentTracker.cs

@@ -101,7 +101,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
                 return;
             }
 
-            var project = _projectManager.FindProject(projectPath);
+            var project = _projectManager.GetProjectWithFilePath(projectPath);
 
             var subscription = _projectManager.Subscribe();
             subscription.ProjectChanged += Subscription_ProjectStateChanged;

test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/ProjectSystem/WorkspaceProjectSnapshotChangeTriggerTest.cs

@@ -6,9 +6,9 @@ using Xunit;
 
 namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
 {
-    public class DefaultProjectStateManagerTest
+    public class WorkspaceProjectSnapshotChangeTriggerTest
     {
-        public DefaultProjectStateManagerTest()
+        public WorkspaceProjectSnapshotChangeTriggerTest()
         {
             Workspace = new AdhocWorkspace();
             EmptySolution = Workspace.CurrentSolution.GetIsolatedSolution();
@@ -44,12 +44,13 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
         public void WorkspaceChanged_SolutionEvents_AddsProjectsInSolution(WorkspaceChangeKind kind)
         {
             // Arrange
-            var projectManager = new DefaultProjectSnapshotManager(Workspace);
+            var trigger = new WorkspaceProjectSnapshotChangeTrigger();
+            var projectManager = new DefaultProjectSnapshotManager(new[] { trigger }, Workspace);
             
             var e = new WorkspaceChangeEventArgs(kind, oldSolution: EmptySolution, newSolution: SolutionWithTwoProjects);
 
             // Act
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             // Assert
             Assert.Collection(
@@ -67,16 +68,17 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
         public void WorkspaceChanged_SolutionEvents_ClearsExistingProjects_AddsProjectsInSolution(WorkspaceChangeKind kind)
         {
             // Arrange
-            var projectManager = new DefaultProjectSnapshotManager(Workspace);
+            var trigger = new WorkspaceProjectSnapshotChangeTrigger();
+            var projectManager = new DefaultProjectSnapshotManager(new[] { trigger }, Workspace);
 
             // Initialize with a project. This will get removed.
             var e = new WorkspaceChangeEventArgs(WorkspaceChangeKind.SolutionAdded, oldSolution: EmptySolution, newSolution: SolutionWithOneProject);
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             e = new WorkspaceChangeEventArgs(kind, oldSolution: EmptySolution, newSolution: SolutionWithTwoProjects);
 
             // Act
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             // Assert
             Assert.Collection(
@@ -91,17 +93,18 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
         public void WorkspaceChanged_ProjectChangeEvents_UpdatesProject(WorkspaceChangeKind kind)
         {
             // Arrange
-            var projectManager = new DefaultProjectSnapshotManager(Workspace);
+            var trigger = new WorkspaceProjectSnapshotChangeTrigger();
+            var projectManager = new DefaultProjectSnapshotManager(new[] { trigger }, Workspace);
 
             // Initialize with some projects.
             var e = new WorkspaceChangeEventArgs(WorkspaceChangeKind.SolutionAdded, oldSolution: EmptySolution, newSolution: SolutionWithTwoProjects);
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             var solution = SolutionWithTwoProjects.WithProjectAssemblyName(ProjectNumberOne.Id, "Changed");
             e = new WorkspaceChangeEventArgs(kind, oldSolution: SolutionWithTwoProjects, newSolution: solution, projectId: ProjectNumberOne.Id);
 
             // Act
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             // Assert
             Assert.Collection(
@@ -118,17 +121,18 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
         public void WorkspaceChanged_ProjectRemovedEvent_RemovesProject()
         {
             // Arrange
-            var projectManager = new DefaultProjectSnapshotManager(Workspace);
+            var trigger = new WorkspaceProjectSnapshotChangeTrigger();
+            var projectManager = new DefaultProjectSnapshotManager(new[] { trigger }, Workspace);
 
             // Initialize with some projects project.
             var e = new WorkspaceChangeEventArgs(WorkspaceChangeKind.SolutionAdded, oldSolution: EmptySolution, newSolution: SolutionWithTwoProjects);
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             var solution = SolutionWithTwoProjects.RemoveProject(ProjectNumberOne.Id);
             e = new WorkspaceChangeEventArgs(WorkspaceChangeKind.ProjectRemoved, oldSolution: SolutionWithTwoProjects, newSolution: solution, projectId: ProjectNumberOne.Id);
 
             // Act
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             // Assert
             Assert.Collection(
@@ -140,13 +144,14 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
         public void WorkspaceChanged_ProjectAddedEvent_AddsProject()
         {
             // Arrange
-            var projectManager = new DefaultProjectSnapshotManager(Workspace);
+            var trigger = new WorkspaceProjectSnapshotChangeTrigger();
+            var projectManager = new DefaultProjectSnapshotManager(new[] { trigger }, Workspace);
 
             var solution = SolutionWithOneProject;
             var e = new WorkspaceChangeEventArgs(WorkspaceChangeKind.ProjectAdded, oldSolution: EmptySolution, newSolution: solution, projectId: ProjectNumberThree.Id);
 
             // Act
-            projectManager.Workspace_WorkspaceChanged(Workspace, e);
+            trigger.Workspace_WorkspaceChanged(Workspace, e);
 
             // Assert
             Assert.Collection(

test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Editor/DefaultVisualStudioDocumentTrackerFactoryTest.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor;
@@ -18,8 +19,10 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 {
     public class DefaultVisualStudioDocumentTrackerFactoryTest : ForegroundDispatcherTestBase
     {
+        private static IReadOnlyList<ProjectSnapshot> Projects = new List<ProjectSnapshot>();
+
         private ProjectSnapshotManager ProjectManager { get; } = Mock.Of<ProjectSnapshotManager>(
-            p => p.FindProject(It.IsAny<string>()) == Mock.Of<ProjectSnapshot>() &&
+            p => p.Projects == Projects &&
             p.Subscribe() == Mock.Of<ProjectSnapshotListener>());
 
         private TextBufferProjectService ProjectService { get; } = Mock.Of<TextBufferProjectService>(