Re-design document synchronization.

- The purpose of this redesign is to make completion more reliable. We now have a great understanding of how VSCode's object model mutates and therefore can make better assumptiosn on how to synchronize it.
- In this changeset we primarily do 2 things to synchronize a document:
  1. Make sure our `IProjectedDocument` has been updated by our language server.
  2. Make sure VSCode's TextDocument reflects the appropriate content detailed by the `IProjectedDocument`
If these two assertions are true then every other extension sees updated C#/Html and can respond accordingly.
- To properly accomplish 2 I had to persist information into the `vscode.TextDocument` to identify when the content properly matches our DTO. We do this by adding a `// SomeNumber` to the end of projected text documents.
- Updated RazorDocumentFactory to generate virtual C# files without a `__` prefix to prevent URIs from being placed as "authoritative" sources labeled by `__`. This caused issues in VSCode when working with copmletion.
- Flowed cancellation tokens into synchronization APIs so that when VSCode cancels an action we can also cancel synchronization.

#210

src/Microsoft.AspNetCore.Razor.VSCode/src/CSharp/CSharpProjectedDocument.ts

@@ -15,6 +15,7 @@ export class CSharpProjectedDocument implements IProjectedDocument {
     private preProvisionalContent: string | undefined;
     private provisionalEditAt: number | undefined;
     private hostDocumentVersion: number | null = null;
+    private projectedDocumentVersion = 0;
 
     public constructor(public readonly uri: vscode.Uri) {
         this.path = getUriPath(uri);
@@ -24,6 +25,10 @@ export class CSharpProjectedDocument implements IProjectedDocument {
         return this.hostDocumentVersion;
     }
 
+    public get projectedDocumentSyncVersion(): number {
+        return this.projectedDocumentVersion;
+    }
+
     public update(edits: ServerTextChange[], hostDocumentVersion: number | null) {
         this.removeProvisionalDot();
 
@@ -85,6 +90,7 @@ export class CSharpProjectedDocument implements IProjectedDocument {
     }
 
     private setContent(content: string) {
+        this.projectedDocumentVersion++;
         this.content = content;
     }
 }

src/Microsoft.AspNetCore.Razor.VSCode/src/CSharp/CSharpProjectedDocumentContentProvider.ts

@@ -27,7 +27,8 @@ export class CSharpProjectedDocumentContentProvider implements vscode.TextDocume
             return;
         }
 
-        const content = razorDocument.csharpDocument.getContent();
+        const content = `${razorDocument.csharpDocument.getContent()}
+// ${razorDocument.csharpDocument.projectedDocumentSyncVersion}`;
 
         return content;
     }

src/Microsoft.AspNetCore.Razor.VSCode/src/Html/HtmlProjectedDocument.ts

@@ -11,6 +11,7 @@ export class HtmlProjectedDocument implements IProjectedDocument {
     public readonly path: string;
     private content = '';
     private hostDocumentVersion: number | null = null;
+    private projectedDocumentVersion = 0;
 
     public constructor(public readonly uri: vscode.Uri) {
         this.path = getUriPath(uri);
@@ -20,12 +21,17 @@ export class HtmlProjectedDocument implements IProjectedDocument {
         return this.hostDocumentVersion;
     }
 
+    public get projectedDocumentSyncVersion(): number {
+        return this.projectedDocumentVersion;
+    }
+
     public getContent() {
         return this.content;
     }
 
     public setContent(content: string, hostDocumentVersion: number | null) {
-        this.content = content;
+        this.projectedDocumentVersion++;
         this.hostDocumentVersion = hostDocumentVersion;
+        this.content = content;
     }
 }

src/Microsoft.AspNetCore.Razor.VSCode/src/Html/HtmlProjectedDocumentContentProvider.ts

@@ -27,7 +27,9 @@ export class HtmlProjectedDocumentContentProvider implements vscode.TextDocument
             return;
         }
 
-        const content = razorDocument.htmlDocument.getContent();
+        const content = `${razorDocument.htmlDocument.getContent()}
+// ${razorDocument.htmlDocument.projectedDocumentSyncVersion}`;
+
         return content;
     }
 

src/Microsoft.AspNetCore.Razor.VSCode/src/IProjectedDocument.ts

@@ -9,5 +9,6 @@ export interface IProjectedDocument {
     readonly path: string;
     readonly uri: vscode.Uri;
     readonly hostDocumentSyncVersion: number | null;
+    readonly projectedDocumentSyncVersion: number;
     getContent(): string;
 }

src/Microsoft.AspNetCore.Razor.VSCode/src/RazorCompletionItemProvider.ts

@@ -73,7 +73,7 @@ export class RazorCompletionItemProvider
     public async provideCompletionItems(
         document: vscode.TextDocument, position: vscode.Position,
         token: vscode.CancellationToken, context: vscode.CompletionContext) {
-        const projection = await this.getProjection(document, position);
+        const projection = await this.getProjection(document, position, token);
 
         if (this.logger.verboseEnabled) {
             this.logger.logVerbose(`Providing completions for document ${getUriPath(document.uri)} ` +

src/Microsoft.AspNetCore.Razor.VSCode/src/RazorDocumentFactory.ts

@@ -27,17 +27,17 @@ export function createDocument(uri: vscode.Uri) {
 }
 
 function createProjectedHtmlDocument(hostDocumentUri: vscode.Uri) {
-    // Index.cshtml => __Index.cshtml.html
-    const projectedPath = `__${hostDocumentUri.path}.html`;
+    // Index.cshtml => Index.cshtml__virtual.html
+    const projectedPath = `${hostDocumentUri.path}__virtual.html`;
     const projectedUri = vscode.Uri.parse(`${HtmlProjectedDocumentContentProvider.scheme}://${projectedPath}`);
     const projectedDocument = new HtmlProjectedDocument(projectedUri);
 
     return projectedDocument;
 }
 
 function createProjectedCSharpDocument(hostDocumentUri: vscode.Uri) {
-    // Index.cshtml => __Index.cshtml__virtual.cs
-    const projectedPath = `__${hostDocumentUri.path}__virtual.cs`;
+    // Index.cshtml => Index.cshtml__virtual.cs
+    const projectedPath = `${hostDocumentUri.path}__virtual.cs`;
     const projectedUri = vscode.Uri.parse(`${CSharpProjectedDocumentContentProvider.scheme}://${projectedPath}`);
     const projectedDocument = new CSharpProjectedDocument(projectedUri);