refactor(compiler): introduce deferred block AST (#51050)

Adds the logic to create `defer`-specific AST nodes from the generic HTML `BlockGroup` and `Block`. The logic for parsing the triggers will be in the next commit.

PR Close #51050

packages/compiler-cli/src/ngtsc/indexer/src/template.ts

@@ -5,7 +5,7 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {AST, ASTWithSource, BoundTarget, ImplicitReceiver, ParseSourceSpan, PropertyRead, PropertyWrite, RecursiveAstVisitor, TmplAstBoundAttribute, TmplAstBoundEvent, TmplAstBoundText, TmplAstElement, TmplAstNode, TmplAstRecursiveVisitor, TmplAstReference, TmplAstTemplate, TmplAstVariable} from '@angular/compiler';
+import {AST, ASTWithSource, BoundTarget, ImplicitReceiver, ParseSourceSpan, PropertyRead, PropertyWrite, RecursiveAstVisitor, TmplAstBoundAttribute, TmplAstBoundEvent, TmplAstBoundText, TmplAstDeferredBlock, TmplAstDeferredBlockError, TmplAstDeferredBlockLoading, TmplAstDeferredBlockPlaceholder, TmplAstElement, TmplAstNode, TmplAstRecursiveVisitor, TmplAstReference, TmplAstTemplate, TmplAstVariable} from '@angular/compiler';
 
 import {ClassDeclaration, DeclarationNode} from '../../reflection';
 
@@ -187,6 +187,7 @@ class TemplateVisitor extends TmplAstRecursiveVisitor {
     this.visitAll(element.children);
     this.visitAll(element.outputs);
   }
+
   override visitTemplate(template: TmplAstTemplate) {
     const templateIdentifier = this.elementOrTemplateToIdentifier(template);
 
@@ -200,6 +201,7 @@ class TemplateVisitor extends TmplAstRecursiveVisitor {
     this.visitAll(template.children);
     this.visitAll(template.references);
   }
+
   override visitBoundAttribute(attribute: TmplAstBoundAttribute) {
     // If the bound attribute has no value, it cannot have any identifiers in the value expression.
     if (attribute.valueSpan === undefined) {
@@ -235,6 +237,25 @@ class TemplateVisitor extends TmplAstRecursiveVisitor {
     this.identifiers.add(variableIdentifier);
   }
 
+  override visitDeferredBlock(deferred: TmplAstDeferredBlock) {
+    this.visitAll(deferred.children);
+    deferred.placeholder?.visit(this);
+    deferred.loading?.visit(this);
+    deferred.error?.visit(this);
+  }
+
+  override visitDeferredBlockPlaceholder(block: TmplAstDeferredBlockPlaceholder) {
+    this.visitAll(block.children);
+  }
+
+  override visitDeferredBlockError(block: TmplAstDeferredBlockError) {
+    this.visitAll(block.children);
+  }
+
+  override visitDeferredBlockLoading(block: TmplAstDeferredBlockLoading) {
+    this.visitAll(block.children);
+  }
+
   /** Creates an identifier for a template element or template node. */
   private elementOrTemplateToIdentifier(node: TmplAstElement|TmplAstTemplate): ElementIdentifier
       |TemplateNodeIdentifier|null {

packages/compiler-cli/src/ngtsc/typecheck/extended/api/api.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AST, ASTWithSource, ParseSourceSpan, RecursiveAstVisitor, TmplAstBoundAttribute, TmplAstBoundEvent, TmplAstBoundText, TmplAstContent, TmplAstElement, TmplAstIcu, TmplAstNode, TmplAstRecursiveVisitor, TmplAstReference, TmplAstTemplate, TmplAstText, TmplAstTextAttribute, TmplAstVariable} from '@angular/compiler';
+import {AST, ASTWithSource, ParseSourceSpan, RecursiveAstVisitor, TmplAstBoundAttribute, TmplAstBoundDeferredTrigger, TmplAstBoundEvent, TmplAstBoundText, TmplAstContent, TmplAstDeferredBlock, TmplAstDeferredBlockError, TmplAstDeferredBlockLoading, TmplAstDeferredBlockPlaceholder, TmplAstDeferredTrigger, TmplAstElement, TmplAstIcu, TmplAstNode, TmplAstRecursiveVisitor, TmplAstReference, TmplAstTemplate, TmplAstText, TmplAstTextAttribute, TmplAstVariable} from '@angular/compiler';
 import ts from 'typescript';
 
 import {NgCompilerOptions} from '../../../core/api';
@@ -159,6 +159,34 @@ class TemplateVisitor<Code extends ErrorCode> extends RecursiveAstVisitor implem
   }
   visitIcu(icu: TmplAstIcu): void {}
 
+
+  visitDeferredBlock(deferred: TmplAstDeferredBlock): void {
+    this.visitAllNodes(deferred.children);
+    this.visitAllNodes(deferred.triggers);
+    this.visitAllNodes(deferred.prefetchTriggers);
+    deferred.placeholder && this.visit(deferred.placeholder);
+    deferred.loading && this.visit(deferred.loading);
+    deferred.error && this.visit(deferred.error);
+  }
+
+  visitDeferredTrigger(trigger: TmplAstDeferredTrigger): void {
+    if (trigger instanceof TmplAstBoundDeferredTrigger) {
+      this.visitAst(trigger.value);
+    }
+  }
+
+  visitDeferredBlockPlaceholder(block: TmplAstDeferredBlockPlaceholder): void {
+    this.visitAllNodes(block.children);
+  }
+
+  visitDeferredBlockError(block: TmplAstDeferredBlockError): void {
+    this.visitAllNodes(block.children);
+  }
+
+  visitDeferredBlockLoading(block: TmplAstDeferredBlockLoading): void {
+    this.visitAllNodes(block.children);
+  }
+
   getDiagnostics(template: TmplAstNode[]): NgTemplateDiagnostic<Code>[] {
     this.diagnostics = [];
     this.visitAllNodes(template);

packages/compiler/src/compiler.ts

@@ -63,7 +63,7 @@ export {SourceMap} from './output/source_map';
 export * from './injectable_compiler_2';
 export * from './render3/partial/api';
 export * from './render3/view/api';
-export {BoundAttribute as TmplAstBoundAttribute, BoundEvent as TmplAstBoundEvent, BoundText as TmplAstBoundText, Content as TmplAstContent, Element as TmplAstElement, Icu as TmplAstIcu, Node as TmplAstNode, RecursiveVisitor as TmplAstRecursiveVisitor, Reference as TmplAstReference, Template as TmplAstTemplate, Text as TmplAstText, TextAttribute as TmplAstTextAttribute, Variable as TmplAstVariable} from './render3/r3_ast';
+export {BoundAttribute as TmplAstBoundAttribute, BoundEvent as TmplAstBoundEvent, BoundText as TmplAstBoundText, Content as TmplAstContent, Element as TmplAstElement, Icu as TmplAstIcu, Node as TmplAstNode, RecursiveVisitor as TmplAstRecursiveVisitor, Reference as TmplAstReference, Template as TmplAstTemplate, Text as TmplAstText, TextAttribute as TmplAstTextAttribute, Variable as TmplAstVariable, DeferredBlock as TmplAstDeferredBlock, DeferredBlockPlaceholder as TmplAstDeferredBlockPlaceholder, DeferredBlockLoading as TmplAstDeferredBlockLoading, DeferredBlockError as TmplAstDeferredBlockError, DeferredTrigger as TmplAstDeferredTrigger, BoundDeferredTrigger as TmplAstBoundDeferredTrigger, IdleDeferredTrigger as TmplAstIdleDeferredTrigger, ImmediateDeferredTrigger as TmplAstImmediateDeferredTrigger, HoverDeferredTrigger as TmplAstHoverDeferredTrigger, TimerDeferredTrigger as TmplAstTimerDeferredTrigger, InteractionDeferredTrigger as TmplAstInteractionDeferredTrigger, ViewportDeferredTrigger as TmplAstViewportDeferredTrigger} from './render3/r3_ast';
 export * from './render3/view/t2_api';
 export * from './render3/view/t2_binder';
 export {Identifiers as R3Identifiers} from './render3/r3_identifiers';

packages/compiler/src/render3/r3_ast.ts

@@ -117,6 +117,88 @@ export class Element implements Node {
   }
 }
 
+export abstract class DeferredTrigger implements Node {
+  constructor(public sourceSpan: ParseSourceSpan) {}
+
+  visit<Result>(visitor: Visitor<Result>): Result {
+    return visitor.visitDeferredTrigger(this);
+  }
+}
+
+export class BoundDeferredTrigger extends DeferredTrigger {
+  constructor(public value: AST, sourceSpan: ParseSourceSpan) {
+    super(sourceSpan);
+  }
+}
+
+export class IdleDeferredTrigger extends DeferredTrigger {}
+
+export class ImmediateDeferredTrigger extends DeferredTrigger {}
+
+export class HoverDeferredTrigger extends DeferredTrigger {}
+
+export class TimerDeferredTrigger extends DeferredTrigger {
+  constructor(public delay: number, sourceSpan: ParseSourceSpan) {
+    super(sourceSpan);
+  }
+}
+
+export class InteractionDeferredTrigger extends DeferredTrigger {
+  constructor(public reference: string|null, sourceSpan: ParseSourceSpan) {
+    super(sourceSpan);
+  }
+}
+
+export class ViewportDeferredTrigger extends DeferredTrigger {
+  constructor(public reference: string|null, sourceSpan: ParseSourceSpan) {
+    super(sourceSpan);
+  }
+}
+
+export class DeferredBlockPlaceholder implements Node {
+  constructor(
+      public children: Node[], public minimumTime: number|null, public sourceSpan: ParseSourceSpan,
+      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+
+  visit<Result>(visitor: Visitor<Result>): Result {
+    return visitor.visitDeferredBlockPlaceholder(this);
+  }
+}
+
+export class DeferredBlockLoading implements Node {
+  constructor(
+      public children: Node[], public afterTime: number|null, public minimumTime: number|null,
+      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
+      public endSourceSpan: ParseSourceSpan|null) {}
+
+  visit<Result>(visitor: Visitor<Result>): Result {
+    return visitor.visitDeferredBlockLoading(this);
+  }
+}
+
+export class DeferredBlockError implements Node {
+  constructor(
+      public children: Node[], public sourceSpan: ParseSourceSpan,
+      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+
+  visit<Result>(visitor: Visitor<Result>): Result {
+    return visitor.visitDeferredBlockError(this);
+  }
+}
+
+export class DeferredBlock implements Node {
+  constructor(
+      public children: Node[], public triggers: DeferredTrigger[],
+      public prefetchTriggers: DeferredTrigger[], public placeholder: DeferredBlockPlaceholder|null,
+      public loading: DeferredBlockLoading|null, public error: DeferredBlockError|null,
+      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
+      public endSourceSpan: ParseSourceSpan|null) {}
+
+  visit<Result>(visitor: Visitor<Result>): Result {
+    return visitor.visitDeferredBlock(this);
+  }
+}
+
 export class Template implements Node {
   constructor(
       // tagName is the name of the container element, if applicable.
@@ -196,6 +278,11 @@ export interface Visitor<Result = any> {
   visitText(text: Text): Result;
   visitBoundText(text: BoundText): Result;
   visitIcu(icu: Icu): Result;
+  visitDeferredBlock(deferred: DeferredBlock): Result;
+  visitDeferredBlockPlaceholder(block: DeferredBlockPlaceholder): Result;
+  visitDeferredBlockError(block: DeferredBlockError): Result;
+  visitDeferredBlockLoading(block: DeferredBlockLoading): Result;
+  visitDeferredTrigger(trigger: DeferredTrigger): Result;
 }
 
 export class RecursiveVisitor implements Visitor<void> {
@@ -214,6 +301,23 @@ export class RecursiveVisitor implements Visitor<void> {
     visitAll(this, template.references);
     visitAll(this, template.variables);
   }
+  visitDeferredBlock(deferred: DeferredBlock): void {
+    visitAll(this, deferred.triggers);
+    visitAll(this, deferred.prefetchTriggers);
+    visitAll(this, deferred.children);
+    deferred.placeholder?.visit(this);
+    deferred.loading?.visit(this);
+    deferred.error?.visit(this);
+  }
+  visitDeferredBlockPlaceholder(block: DeferredBlockPlaceholder): void {
+    visitAll(this, block.children);
+  }
+  visitDeferredBlockError(block: DeferredBlockError): void {
+    visitAll(this, block.children);
+  }
+  visitDeferredBlockLoading(block: DeferredBlockLoading): void {
+    visitAll(this, block.children);
+  }
   visitContent(content: Content): void {}
   visitVariable(variable: Variable): void {}
   visitReference(reference: Reference): void {}
@@ -223,6 +327,7 @@ export class RecursiveVisitor implements Visitor<void> {
   visitText(text: Text): void {}
   visitBoundText(text: BoundText): void {}
   visitIcu(icu: Icu): void {}
+  visitDeferredTrigger(trigger: DeferredTrigger): void {}
 }