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refactor(language-service): Simplify ExpressionVisitor in completions…
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….ts (#33391)

This commit simplifies the logic of `ExpressionVisitor` in
`completions.ts`.

Specifically,

1. helper functions `uniqueByName` and `lowerName` are removed.
2. Clean up the logic in visitElement()
3. Reorder constructor params
4. Add methods `addAttributeValuesToCompletions`,
`addKeysToCompletions`, and `addSymbolsToCompletions`.

PR Close #33391
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@kyliau @AndrewKushnir
kyliau authored and AndrewKushnir committed Oct 28, 2019
1 parent eb0d8c0 commit c61f413
Showing 1 changed file with 102 additions and 118 deletions.
220 changes: 102 additions & 118 deletions packages/language-service/src/completions.ts
View file
Expand Up @@ -6,7 +6,7 @@
* found in the LICENSE file at https://angular.io/license
*/

import {AST, AstPath, Attribute, BoundDirectivePropertyAst, BoundElementPropertyAst, BoundEventAst, BoundTextAst, Element, ElementAst, ImplicitReceiver, NAMED_ENTITIES, Node as HtmlAst, NullTemplateVisitor, ParseSpan, PropertyRead, TagContentType, Text, findNode, getHtmlTagDefinition} from '@angular/compiler';
import {AST, AstPath, Attribute, BoundDirectivePropertyAst, BoundElementPropertyAst, BoundEventAst, BoundTextAst, CssSelector, Element, ElementAst, ImplicitReceiver, NAMED_ENTITIES, Node as HtmlAst, NullTemplateVisitor, ParseSpan, PropertyRead, TagContentType, Text, findNode, getHtmlTagDefinition} from '@angular/compiler';
import {getExpressionScope} from '@angular/compiler-cli/src/language_services';

import {AstResult} from './common';
Expand Down Expand Up @@ -168,19 +168,21 @@ function attributeValueCompletions(
}
const dinfo = diagnosticInfoFromTemplateInfo(info);
const visitor =
new ExpressionVisitor(info, position, attr, () => getExpressionScope(dinfo, path, false));
new ExpressionVisitor(info, position, () => getExpressionScope(dinfo, path, false), attr);
path.tail.visit(visitor, null);
if (!visitor.result || !visitor.result.length) {
// Try allwoing widening the path
const widerPath = findTemplateAstAt(info.templateAst, position, /* allowWidening */ true);
if (widerPath.tail) {
const widerVisitor = new ExpressionVisitor(
info, position, attr, () => getExpressionScope(dinfo, widerPath, false));
widerPath.tail.visit(widerVisitor, null);
return widerVisitor.result || [];
}
const {results} = visitor;
if (results.length) {
return results;
}
// Try allowing widening the path
const widerPath = findTemplateAstAt(info.templateAst, position, /* allowWidening */ true);
if (widerPath.tail) {
const widerVisitor = new ExpressionVisitor(
info, position, () => getExpressionScope(dinfo, widerPath, false), attr);
widerPath.tail.visit(widerVisitor, null);
return widerVisitor.results;
}
return visitor.result || [];
return results;
}

function elementCompletions(info: AstResult): ng.CompletionEntry[] {
Expand Down Expand Up @@ -208,22 +210,6 @@ function elementCompletions(info: AstResult): ng.CompletionEntry[] {
return results;
}

/**
* Filter the specified `entries` by unique name.
* @param entries Completion Entries
*/
function uniqueByName(entries: ng.CompletionEntry[]) {
const results = [];
const set = new Set();
for (const entry of entries) {
if (!set.has(entry.name)) {
set.add(entry.name);
results.push(entry);
}
}
return results;
}

function entityCompletions(value: string, position: number): ng.CompletionEntry[] {
// Look for entity completions
const re = /&[A-Za-z]*;?(?!\d)/g;
Expand Down Expand Up @@ -252,10 +238,10 @@ function interpolationCompletions(info: AstResult, position: number): ng.Complet
return [];
}
const visitor = new ExpressionVisitor(
info, position, undefined,
info, position,
() => getExpressionScope(diagnosticInfoFromTemplateInfo(info), templatePath, false));
templatePath.tail.visit(visitor, null);
return uniqueByName(visitor.result || []);
return visitor.results;
}

// There is a special case of HTML where text that contains a unclosed tag is treated as
Expand All @@ -280,76 +266,58 @@ function voidElementAttributeCompletions(
}

class ExpressionVisitor extends NullTemplateVisitor {
private getExpressionScope: () => ng.SymbolTable;
result: ng.CompletionEntry[]|undefined;
private readonly completions = new Map<string, ng.CompletionEntry>();

constructor(
private info: AstResult, private position: number, private attr?: Attribute,
getExpressionScope?: () => ng.SymbolTable) {
private readonly info: AstResult, private readonly position: number,
private readonly getExpressionScope: () => ng.SymbolTable,
private readonly attr?: Attribute) {
super();
this.getExpressionScope = getExpressionScope || (() => info.template.members);
}

get results(): ng.CompletionEntry[] { return Array.from(this.completions.values()); }

visitDirectiveProperty(ast: BoundDirectivePropertyAst): void {
this.attributeValueCompletions(ast.value);
this.addAttributeValuesToCompletions(ast.value);
}

visitElementProperty(ast: BoundElementPropertyAst): void {
this.attributeValueCompletions(ast.value);
this.addAttributeValuesToCompletions(ast.value);
}

visitEvent(ast: BoundEventAst): void { this.attributeValueCompletions(ast.handler); }
visitEvent(ast: BoundEventAst): void { this.addAttributeValuesToCompletions(ast.handler); }

visitElement(ast: ElementAst): void {
if (this.attr && getSelectors(this.info) && this.attr.name.startsWith(TEMPLATE_ATTR_PREFIX)) {
// The value is a template expression but the expression AST was not produced when the
// TemplateAst was produce so
// do that now.

const key = this.attr.name.substr(TEMPLATE_ATTR_PREFIX.length);

// Find the selector
const selectorInfo = getSelectors(this.info);
const selectors = selectorInfo.selectors;
const selector =
selectors.filter(s => s.attrs.some((attr, i) => i % 2 === 0 && attr === key))[0];

const templateBindingResult =
this.info.expressionParser.parseTemplateBindings(key, this.attr.value, null, 0);

// find the template binding that contains the position
if (!this.attr.valueSpan) return;
const valueRelativePosition = this.position - this.attr.valueSpan.start.offset;
const bindings = templateBindingResult.templateBindings;
const binding =
bindings.find(
binding => inSpan(valueRelativePosition, binding.span, /* exclusive */ true)) ||
bindings.find(binding => inSpan(valueRelativePosition, binding.span));

const keyCompletions = () => {
let keys: string[] = [];
if (selector) {
const attrNames = selector.attrs.filter((_, i) => i % 2 === 0);
keys = attrNames.filter(name => name.startsWith(key) && name != key)
.map(name => lowerName(name.substr(key.length)));
}
keys.push('let');
this.result = keys.map(key => {
return {
name: key,
kind: ng.CompletionKind.KEY,
sortText: key,
};
});
};
if (!this.attr || !this.attr.valueSpan || !this.attr.name.startsWith(TEMPLATE_ATTR_PREFIX)) {
return;
}

// The value is a template expression but the expression AST was not produced when the
// TemplateAst was produce so do that now.
const key = this.attr.name.substr(TEMPLATE_ATTR_PREFIX.length);
// Find the selector
const selectorInfo = getSelectors(this.info);
const selectors = selectorInfo.selectors;
const selector =
selectors.filter(s => s.attrs.some((attr, i) => i % 2 === 0 && attr === key))[0];
if (!selector) {
return;
}

if (!binding || (binding.key === key && !binding.expression)) {
// We are in the root binding. We should return `let` and keys that are left in the
// selector.
keyCompletions();
} else if (binding.keyIsVar) {
const templateBindingResult =
this.info.expressionParser.parseTemplateBindings(key, this.attr.value, null, 0);

// find the template binding that contains the position
const valueRelativePosition = this.position - this.attr.valueSpan.start.offset;
const bindings = templateBindingResult.templateBindings;
const binding =
bindings.find(
binding => inSpan(valueRelativePosition, binding.span, /* exclusive */ true)) ||
bindings.find(binding => inSpan(valueRelativePosition, binding.span));

if (binding) {
if (binding.keyIsVar) {
const equalLocation = this.attr.value.indexOf('=');
this.result = [];
if (equalLocation >= 0 && valueRelativePosition >= equalLocation) {
// We are after the '=' in a let clause. The valid values here are the members of the
// template reference's type parameter.
Expand All @@ -358,61 +326,81 @@ class ExpressionVisitor extends NullTemplateVisitor {
const contextTable =
this.info.template.query.getTemplateContext(directiveMetadata.type.reference);
if (contextTable) {
this.result = this.symbolsToCompletions(contextTable.values());
this.addSymbolsToCompletions(contextTable.values());
return;
}
}
} else if (binding.key && valueRelativePosition <= (binding.key.length - key.length)) {
keyCompletions();
}
} else {
// If the position is in the expression or after the key or there is no key, return the
// expression completions
if ((binding.expression && inSpan(valueRelativePosition, binding.expression.ast.span)) ||
(binding.key &&
valueRelativePosition > binding.span.start + (binding.key.length - key.length)) ||
!binding.key) {
const span = new ParseSpan(0, this.attr.value.length);
const offset = ast.sourceSpan.start.offset;
this.attributeValueCompletions(
binding.expression ? binding.expression.ast :
new PropertyRead(
span, span.toAbsolute(offset),
new ImplicitReceiver(span, span.toAbsolute(offset)), ''),
this.position);
}
if ((binding.expression && inSpan(valueRelativePosition, binding.expression.ast.span)) ||
// If the position is in the expression or after the key or there is no key, return the
// expression completions
valueRelativePosition > binding.span.start + binding.key.length - key.length) {
const span = new ParseSpan(0, this.attr.value.length);
const offset = ast.sourceSpan.start.offset;
let expressionAst: AST;
if (binding.expression) {
expressionAst = binding.expression.ast;
} else {
keyCompletions();
const receiver = new ImplicitReceiver(span, span.toAbsolute(offset));
expressionAst = new PropertyRead(span, span.toAbsolute(offset), receiver, '');
}
this.addAttributeValuesToCompletions(expressionAst, this.position);
return;
}
}

this.addKeysToCompletions(selector, key);
}

visitBoundText(ast: BoundTextAst) {
if (inSpan(this.position, ast.value.sourceSpan)) {
const completions = getExpressionCompletions(
this.getExpressionScope(), ast.value, this.position, this.info.template.query);
if (completions) {
this.result = this.symbolsToCompletions(completions);
this.addSymbolsToCompletions(completions);
}
}
}

private attributeValueCompletions(value: AST, position?: number) {
private addAttributeValuesToCompletions(value: AST, position?: number) {
const symbols = getExpressionCompletions(
this.getExpressionScope(), value,
position === undefined ? this.attributeValuePosition : position, this.info.template.query);
if (symbols) {
this.result = this.symbolsToCompletions(symbols);
this.addSymbolsToCompletions(symbols);
}
}

private symbolsToCompletions(symbols: ng.Symbol[]): ng.CompletionEntry[] {
return symbols.filter(s => !s.name.startsWith('__') && s.public).map(symbol => {
return {
name: symbol.name,
kind: symbol.kind as ng.CompletionKind,
sortText: symbol.name,
};
private addKeysToCompletions(selector: CssSelector, key: string) {
if (key !== 'ngFor') {
return;
}
this.completions.set('let', {
name: 'let',
kind: ng.CompletionKind.KEY,
sortText: 'let',
});
if (selector.attrs.some(attr => attr === 'ngForOf')) {
this.completions.set('of', {
name: 'of',
kind: ng.CompletionKind.KEY,
sortText: 'of',
});
}
}

private addSymbolsToCompletions(symbols: ng.Symbol[]) {
for (const s of symbols) {
if (s.name.startsWith('__') || !s.public || this.completions.has(s.name)) {
continue;
}
this.completions.set(s.name, {
name: s.name,
kind: s.kind as ng.CompletionKind,
sortText: s.name,
});
}
}

private get attributeValuePosition() {
Expand All @@ -427,10 +415,6 @@ function getSourceText(template: ng.TemplateSource, span: ng.Span): string {
return template.source.substring(span.start, span.end);
}

function lowerName(name: string): string {
return name && (name[0].toLowerCase() + name.substr(1));
}

function angularAttributes(info: AstResult, elementName: string): ng.CompletionEntry[] {
const {selectors, map: selectorMap} = getSelectors(info);
const templateRefs = new Set<string>();
Expand Down

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