refactor(language-service): Remove NgLSHost -> NgLS dependency (#31122)

```
NgLSHost: AngularLanguageServiceHost
NgLS: AngularLanguageService
```

NgLSHost should not depend on NgLS, because it introduces circular
dependency.
Instead, the `getTemplateAst` and `getTemplatAstAtPosition` methods should
be moved to NgLSHost and exposed as public methods.
This removes the circular dependency, and also removes the need for the
awkward 'setSite' method in NgLSHost.

PR Close #31122

packages/language-service/src/diagnostics.ts

@@ -7,49 +7,13 @@
  */
 
 import {NgAnalyzedModules, StaticSymbol} from '@angular/compiler';
-import {DiagnosticTemplateInfo, getTemplateExpressionDiagnostics} from '@angular/compiler-cli/src/language_services';
-
 import {AstResult} from './common';
 import {Declarations, Diagnostic, DiagnosticKind, DiagnosticMessageChain, Diagnostics, Span, TemplateSource} from './types';
-import {offsetSpan, spanOf} from './utils';
 
 export interface AstProvider {
   getTemplateAst(template: TemplateSource, fileName: string): AstResult;
 }
 
-export function getTemplateDiagnostics(
-    fileName: string, astProvider: AstProvider, templates: TemplateSource[]): Diagnostics {
-  const results: Diagnostics = [];
-  for (const template of templates) {
-    const ast = astProvider.getTemplateAst(template, fileName);
-    if (ast) {
-      if (ast.parseErrors && ast.parseErrors.length) {
-        results.push(...ast.parseErrors.map<Diagnostic>(
-            e => ({
-              kind: DiagnosticKind.Error,
-              span: offsetSpan(spanOf(e.span), template.span.start),
-              message: e.msg
-            })));
-      } else if (ast.templateAst && ast.htmlAst) {
-        const info: DiagnosticTemplateInfo = {
-          templateAst: ast.templateAst,
-          htmlAst: ast.htmlAst,
-          offset: template.span.start,
-          query: template.query,
-          members: template.members
-        };
-        const expressionDiagnostics = getTemplateExpressionDiagnostics(info);
-        results.push(...expressionDiagnostics);
-      }
-      if (ast.errors) {
-        results.push(...ast.errors.map<Diagnostic>(
-            e => ({kind: e.kind, span: e.span || template.span, message: e.message})));
-      }
-    }
-  }
-  return results;
-}
-
 export function getDeclarationDiagnostics(
     declarations: Declarations, modules: NgAnalyzedModules): Diagnostics {
   const results: Diagnostics = [];

packages/language-service/src/language_service.ts

@@ -6,14 +6,16 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {CompileMetadataResolver, CompileNgModuleMetadata, CompilePipeSummary, CompilerConfig, DomElementSchemaRegistry, HtmlParser, I18NHtmlParser, Lexer, NgAnalyzedModules, Parser, TemplateParser} from '@angular/compiler';
+import {CompileMetadataResolver, CompilePipeSummary} from '@angular/compiler';
+import {DiagnosticTemplateInfo, getTemplateExpressionDiagnostics} from '@angular/compiler-cli/src/language_services';
 
-import {AstResult, TemplateInfo} from './common';
 import {getTemplateCompletions} from './completions';
 import {getDefinition} from './definitions';
-import {getDeclarationDiagnostics, getTemplateDiagnostics} from './diagnostics';
+import {getDeclarationDiagnostics} from './diagnostics';
 import {getHover} from './hover';
 import {Completions, Definition, Diagnostic, DiagnosticKind, Diagnostics, Hover, LanguageService, LanguageServiceHost, Span, TemplateSource} from './types';
+import {offsetSpan, spanOf} from './utils';
+
 
 
 /**
@@ -36,7 +38,7 @@ class LanguageServiceImpl implements LanguageService {
     let results: Diagnostics = [];
     let templates = this.host.getTemplates(fileName);
     if (templates && templates.length) {
-      results.push(...getTemplateDiagnostics(fileName, this, templates));
+      results.push(...this.getTemplateDiagnostics(fileName, templates));
     }
 
     let declarations = this.host.getDeclarations(fileName);
@@ -49,7 +51,7 @@ class LanguageServiceImpl implements LanguageService {
   }
 
   getPipesAt(fileName: string, position: number): CompilePipeSummary[] {
-    let templateInfo = this.getTemplateAstAtPosition(fileName, position);
+    let templateInfo = this.host.getTemplateAstAtPosition(fileName, position);
     if (templateInfo) {
       return templateInfo.pipes;
     }
@@ -57,98 +59,57 @@ class LanguageServiceImpl implements LanguageService {
   }
 
   getCompletionsAt(fileName: string, position: number): Completions {
-    let templateInfo = this.getTemplateAstAtPosition(fileName, position);
+    let templateInfo = this.host.getTemplateAstAtPosition(fileName, position);
     if (templateInfo) {
       return getTemplateCompletions(templateInfo);
     }
   }
 
   getDefinitionAt(fileName: string, position: number): Definition {
-    let templateInfo = this.getTemplateAstAtPosition(fileName, position);
+    let templateInfo = this.host.getTemplateAstAtPosition(fileName, position);
     if (templateInfo) {
       return getDefinition(templateInfo);
     }
   }
 
   getHoverAt(fileName: string, position: number): Hover|undefined {
-    let templateInfo = this.getTemplateAstAtPosition(fileName, position);
+    let templateInfo = this.host.getTemplateAstAtPosition(fileName, position);
     if (templateInfo) {
       return getHover(templateInfo);
     }
   }
 
-  private getTemplateAstAtPosition(fileName: string, position: number): TemplateInfo|undefined {
+  private getTemplateDiagnostics(fileName: string, templates: TemplateSource[]): Diagnostics {
-    let template = this.host.getTemplateAt(fileName, position);
+    const results: Diagnostics = [];
-    if (template) {
+    for (const template of templates) {
-      let astResult = this.getTemplateAst(template, fileName);
+      const ast = this.host.getTemplateAst(template, fileName);
-      if (astResult && astResult.htmlAst && astResult.templateAst && astResult.directive &&
+      if (ast) {
-          astResult.directives && astResult.pipes && astResult.expressionParser)
+        if (ast.parseErrors && ast.parseErrors.length) {
-        return {
+          results.push(...ast.parseErrors.map<Diagnostic>(
-          position,
+              e => ({
-          fileName,
+                kind: DiagnosticKind.Error,
-          template,
+                span: offsetSpan(spanOf(e.span), template.span.start),
-          htmlAst: astResult.htmlAst,
+                message: e.msg
-          directive: astResult.directive,
+              })));
-          directives: astResult.directives,
+        } else if (ast.templateAst && ast.htmlAst) {
-          pipes: astResult.pipes,
+          const info: DiagnosticTemplateInfo = {
-          templateAst: astResult.templateAst,
+            templateAst: ast.templateAst,
-          expressionParser: astResult.expressionParser
+            htmlAst: ast.htmlAst,
+            offset: template.span.start,
+            query: template.query,
+            members: template.members
           };
+          const expressionDiagnostics = getTemplateExpressionDiagnostics(info);
+          results.push(...expressionDiagnostics);
         }
-    return undefined;
+        if (ast.errors) {
-  }
+          results.push(...ast.errors.map<Diagnostic>(
-
+              e => ({kind: e.kind, span: e.span || template.span, message: e.message})));
-  getTemplateAst(template: TemplateSource, contextFile: string): AstResult {
-    let result: AstResult|undefined = undefined;
-    try {
-      const resolvedMetadata =
-          this.metadataResolver.getNonNormalizedDirectiveMetadata(template.type as any);
-      const metadata = resolvedMetadata && resolvedMetadata.metadata;
-      if (metadata) {
-        const rawHtmlParser = new HtmlParser();
-        const htmlParser = new I18NHtmlParser(rawHtmlParser);
-        const expressionParser = new Parser(new Lexer());
-        const config = new CompilerConfig();
-        const parser = new TemplateParser(
-            config, this.host.resolver.getReflector(), expressionParser,
-            new DomElementSchemaRegistry(), htmlParser, null !, []);
-        const htmlResult = htmlParser.parse(template.source, '', {tokenizeExpansionForms: true});
-        const analyzedModules = this.host.getAnalyzedModules();
-        let errors: Diagnostic[]|undefined = undefined;
-        let ngModule = analyzedModules.ngModuleByPipeOrDirective.get(template.type);
-        if (!ngModule) {
-          // Reported by the the declaration diagnostics.
-          ngModule = findSuitableDefaultModule(analyzedModules);
-        }
-        if (ngModule) {
-          const resolvedDirectives = ngModule.transitiveModule.directives.map(
-              d => this.host.resolver.getNonNormalizedDirectiveMetadata(d.reference));
-          const directives = removeMissing(resolvedDirectives).map(d => d.metadata.toSummary());
-          const pipes = ngModule.transitiveModule.pipes.map(
-              p => this.host.resolver.getOrLoadPipeMetadata(p.reference).toSummary());
-          const schemas = ngModule.schemas;
-          const parseResult = parser.tryParseHtml(htmlResult, metadata, directives, pipes, schemas);
-          result = {
-            htmlAst: htmlResult.rootNodes,
-            templateAst: parseResult.templateAst,
-            directive: metadata, directives, pipes,
-            parseErrors: parseResult.errors, expressionParser, errors
-          };
         }
       }
-    } catch (e) {
-      let span = template.span;
-      if (e.fileName == contextFile) {
-        span = template.query.getSpanAt(e.line, e.column) || span;
     }
-      result = {errors: [{kind: DiagnosticKind.Error, message: e.message, span}]};
+    return results;
   }
-    return result || {};
-  }
-}
-
-function removeMissing<T>(values: (T | null | undefined)[]): T[] {
-  return values.filter(e => !!e) as T[];
 }
 
 function uniqueBySpan < T extends {
@@ -173,16 +134,3 @@ function uniqueBySpan < T extends {
     return result;
   }
 }
-
-function findSuitableDefaultModule(modules: NgAnalyzedModules): CompileNgModuleMetadata|undefined {
-  let result: CompileNgModuleMetadata|undefined = undefined;
-  let resultSize = 0;
-  for (const module of modules.ngModules) {
-    const moduleSize = module.transitiveModule.directives.length;
-    if (moduleSize > resultSize) {
-      result = module;
-      resultSize = moduleSize;
-    }
-  }
-  return result;
-}

packages/language-service/src/ts_plugin.ts

@@ -81,7 +81,6 @@ export function create(info: tss.server.PluginCreateInfo): ts.LanguageService {
 
   const serviceHost = new TypeScriptServiceHost(info.languageServiceHost, oldLS);
   const ls = createLanguageService(serviceHost);
-  serviceHost.setSite(ls);
   projectHostMap.set(info.project, serviceHost);
 
   proxy.getCompletionsAtPosition = function(

packages/language-service/src/types.ts

@@ -8,6 +8,7 @@
 
 import {CompileDirectiveMetadata, CompileMetadataResolver, CompilePipeSummary, NgAnalyzedModules, StaticSymbol} from '@angular/compiler';
 import {BuiltinType, DeclarationKind, Definition, PipeInfo, Pipes, Signature, Span, Symbol, SymbolDeclaration, SymbolQuery, SymbolTable} from '@angular/compiler-cli/src/language_services';
+import {AstResult, TemplateInfo} from './common';
 
 export {
   BuiltinType,
@@ -203,6 +204,16 @@ export interface LanguageServiceHost {
    * Return a list all the template files referenced by the project.
    */
   getTemplateReferences(): string[];
+
+  /**
+   * Return the AST for both HTML and template for the contextFile.
+   */
+  getTemplateAst(template: TemplateSource, contextFile: string): AstResult;
+
+  /**
+   * Return the template AST for the node that corresponds to the position.
+   */
+  getTemplateAstAtPosition(fileName: string, position: number): TemplateInfo|undefined;
 }
 
 /**

packages/language-service/src/typescript_host.ts

@@ -6,16 +6,18 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AotSummaryResolver, CompileMetadataResolver, CompilerConfig, DirectiveNormalizer, DirectiveResolver, DomElementSchemaRegistry, FormattedError, FormattedMessageChain, HtmlParser, JitSummaryResolver, NgAnalyzedModules, NgModuleResolver, ParseTreeResult, PipeResolver, ResourceLoader, StaticReflector, StaticSymbol, StaticSymbolCache, StaticSymbolResolver, analyzeNgModules, createOfflineCompileUrlResolver, isFormattedError} from '@angular/compiler';
+import {AotSummaryResolver, CompileMetadataResolver, CompileNgModuleMetadata, CompilePipeSummary, CompilerConfig, DirectiveNormalizer, DirectiveResolver, DomElementSchemaRegistry, FormattedError, FormattedMessageChain, HtmlParser, I18NHtmlParser, JitSummaryResolver, Lexer, NgAnalyzedModules, NgModuleResolver, ParseTreeResult, Parser, PipeResolver, ResourceLoader, StaticReflector, StaticSymbol, StaticSymbolCache, StaticSymbolResolver, TemplateParser, analyzeNgModules, createOfflineCompileUrlResolver, isFormattedError} from '@angular/compiler';
 import {CompilerOptions, getClassMembersFromDeclaration, getPipesTable, getSymbolQuery} from '@angular/compiler-cli/src/language_services';
 import {ViewEncapsulation, ɵConsole as Console} from '@angular/core';
 import * as fs from 'fs';
 import * as path from 'path';
 import * as ts from 'typescript';
 
+import {AstResult, TemplateInfo} from './common';
 import {createLanguageService} from './language_service';
 import {ReflectorHost} from './reflector_host';
-import {Declaration, DeclarationError, Declarations, DiagnosticMessageChain, LanguageService, LanguageServiceHost, Span, Symbol, SymbolQuery, TemplateSource, TemplateSources} from './types';
+import {Declaration, DeclarationError, Declarations, Diagnostic, DiagnosticKind, DiagnosticMessageChain, LanguageService, LanguageServiceHost, Span, Symbol, SymbolQuery, TemplateSource, TemplateSources} from './types';
+
 
 
 /**
@@ -25,7 +27,6 @@ export function createLanguageServiceFromTypescript(
     host: ts.LanguageServiceHost, service: ts.LanguageService): LanguageService {
   const ngHost = new TypeScriptServiceHost(host, service);
   const ngServer = createLanguageService(ngHost);
-  ngHost.setSite(ngServer);
   return ngServer;
 }
 
@@ -75,8 +76,6 @@ export class TypeScriptServiceHost implements LanguageServiceHost {
   // TODO(issue/24571): remove '!'.
   private analyzedModules !: NgAnalyzedModules | null;
   // TODO(issue/24571): remove '!'.
-  private service !: LanguageService;
-  // TODO(issue/24571): remove '!'.
   private fileToComponent !: Map<string, StaticSymbol>| null;
   // TODO(issue/24571): remove '!'.
   private templateReferences !: string[] | null;
@@ -86,8 +85,6 @@ export class TypeScriptServiceHost implements LanguageServiceHost {
 
   constructor(private host: ts.LanguageServiceHost, private tsService: ts.LanguageService) {}
 
-  setSite(service: LanguageService) { this.service = service; }
-
   /**
    * Angular LanguageServiceHost implementation
    */
@@ -323,7 +320,11 @@ export class TypeScriptServiceHost implements LanguageServiceHost {
         },
         get query() {
           if (!queryCache) {
-            const pipes = t.service.getPipesAt(fileName, node.getStart());
+            let pipes: CompilePipeSummary[] = [];
+            const templateInfo = t.getTemplateAstAtPosition(fileName, node.getStart());
+            if (templateInfo) {
+              pipes = templateInfo.pipes;
+            }
             queryCache = getSymbolQuery(
                 t.program !, t.checker, sourceFile,
                 () => getPipesTable(sourceFile, t.program !, t.checker, pipes));
@@ -590,8 +591,91 @@ export class TypeScriptServiceHost implements LanguageServiceHost {
 
     return find(sourceFile);
   }
+
+  getTemplateAstAtPosition(fileName: string, position: number): TemplateInfo|undefined {
+    let template = this.getTemplateAt(fileName, position);
+    if (template) {
+      let astResult = this.getTemplateAst(template, fileName);
+      if (astResult && astResult.htmlAst && astResult.templateAst && astResult.directive &&
+          astResult.directives && astResult.pipes && astResult.expressionParser)
+        return {
+          position,
+          fileName,
+          template,
+          htmlAst: astResult.htmlAst,
+          directive: astResult.directive,
+          directives: astResult.directives,
+          pipes: astResult.pipes,
+          templateAst: astResult.templateAst,
+          expressionParser: astResult.expressionParser
+        };
+    }
+    return undefined;
   }
 
+  getTemplateAst(template: TemplateSource, contextFile: string): AstResult {
+    let result: AstResult|undefined = undefined;
+    try {
+      const resolvedMetadata =
+          this.resolver.getNonNormalizedDirectiveMetadata(template.type as any);
+      const metadata = resolvedMetadata && resolvedMetadata.metadata;
+      if (metadata) {
+        const rawHtmlParser = new HtmlParser();
+        const htmlParser = new I18NHtmlParser(rawHtmlParser);
+        const expressionParser = new Parser(new Lexer());
+        const config = new CompilerConfig();
+        const parser = new TemplateParser(
+            config, this.resolver.getReflector(), expressionParser, new DomElementSchemaRegistry(),
+            htmlParser, null !, []);
+        const htmlResult = htmlParser.parse(template.source, '', {tokenizeExpansionForms: true});
+        const analyzedModules = this.getAnalyzedModules();
+        let errors: Diagnostic[]|undefined = undefined;
+        let ngModule = analyzedModules.ngModuleByPipeOrDirective.get(template.type);
+        if (!ngModule) {
+          // Reported by the the declaration diagnostics.
+          ngModule = findSuitableDefaultModule(analyzedModules);
+        }
+        if (ngModule) {
+          const directives =
+              ngModule.transitiveModule.directives
+                  .map(d => this.resolver.getNonNormalizedDirectiveMetadata(d.reference))
+                  .filter(d => d)
+                  .map(d => d !.metadata.toSummary());
+          const pipes = ngModule.transitiveModule.pipes.map(
+              p => this.resolver.getOrLoadPipeMetadata(p.reference).toSummary());
+          const schemas = ngModule.schemas;
+          const parseResult = parser.tryParseHtml(htmlResult, metadata, directives, pipes, schemas);
+          result = {
+            htmlAst: htmlResult.rootNodes,
+            templateAst: parseResult.templateAst,
+            directive: metadata, directives, pipes,
+            parseErrors: parseResult.errors, expressionParser, errors
+          };
+        }
+      }
+    } catch (e) {
+      let span = template.span;
+      if (e.fileName == contextFile) {
+        span = template.query.getSpanAt(e.line, e.column) || span;
+      }
+      result = {errors: [{kind: DiagnosticKind.Error, message: e.message, span}]};
+    }
+    return result || {};
+  }
+}
+
+function findSuitableDefaultModule(modules: NgAnalyzedModules): CompileNgModuleMetadata|undefined {
+  let result: CompileNgModuleMetadata|undefined = undefined;
+  let resultSize = 0;
+  for (const module of modules.ngModules) {
+    const moduleSize = module.transitiveModule.directives.length;
+    if (moduleSize > resultSize) {
+      result = module;
+      resultSize = moduleSize;
+    }
+  }
+  return result;
+}
 
 function findTsConfig(fileName: string): string|undefined {
   let dir = path.dirname(fileName);

packages/language-service/test/completions_spec.ts

@@ -22,7 +22,6 @@ describe('completions', () => {
   let service = ts.createLanguageService(mockHost, documentRegistry);
   let ngHost = new TypeScriptServiceHost(mockHost, service);
   let ngService = createLanguageService(ngHost);
-  ngHost.setSite(ngService);
 
   it('should be able to get entity completions',
      () => { contains('/app/test.ng', 'entity-amp', '&', '>', '<', 'ι'); });

packages/language-service/test/definitions_spec.ts

@@ -22,7 +22,6 @@ describe('definitions', () => {
   let service = ts.createLanguageService(mockHost, documentRegistry);
   let ngHost = new TypeScriptServiceHost(mockHost, service);
   let ngService = createLanguageService(ngHost);
-  ngHost.setSite(ngService);
 
   it('should be able to find field in an interpolation', () => {
     localReference(

packages/language-service/test/diagnostics_spec.ts

@@ -26,7 +26,6 @@ describe('diagnostics', () => {
     const service = ts.createLanguageService(mockHost, documentRegistry);
     ngHost = new TypeScriptServiceHost(mockHost, service);
     ngService = createLanguageService(ngHost);
-    ngHost.setSite(ngService);
   });
 
   it('should be no diagnostics for test.ng',

packages/language-service/test/hover_spec.ts

@@ -23,7 +23,6 @@ describe('hover', () => {
   let service = ts.createLanguageService(mockHost, documentRegistry);
   let ngHost = new TypeScriptServiceHost(mockHost, service);
   let ngService = createLanguageService(ngHost);
-  ngHost.setSite(ngService);
 
 
   it('should be able to find field in an interpolation', () => {

packages/language-service/test/template_references_spec.ts

@@ -27,7 +27,6 @@ describe('references', () => {
     service = ts.createLanguageService(mockHost, documentRegistry);
     ngHost = new TypeScriptServiceHost(mockHost, service);
     ngService = createLanguageService(ngHost);
-    ngHost.setSite(ngService);
   });
 
   it('should be able to get template references',