355 lines
12 KiB
JavaScript
355 lines
12 KiB
JavaScript
/**
|
|
* @fileoverview The event generator for AST nodes.
|
|
* @author Toru Nagashima
|
|
*/
|
|
|
|
"use strict";
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Requirements
|
|
//------------------------------------------------------------------------------
|
|
|
|
const esquery = require("esquery");
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Typedefs
|
|
//------------------------------------------------------------------------------
|
|
|
|
/**
|
|
* An object describing an AST selector
|
|
* @typedef {Object} ASTSelector
|
|
* @property {string} rawSelector The string that was parsed into this selector
|
|
* @property {boolean} isExit `true` if this should be emitted when exiting the node rather than when entering
|
|
* @property {Object} parsedSelector An object (from esquery) describing the matching behavior of the selector
|
|
* @property {string[]|null} listenerTypes A list of node types that could possibly cause the selector to match,
|
|
* or `null` if all node types could cause a match
|
|
* @property {number} attributeCount The total number of classes, pseudo-classes, and attribute queries in this selector
|
|
* @property {number} identifierCount The total number of identifier queries in this selector
|
|
*/
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Helpers
|
|
//------------------------------------------------------------------------------
|
|
|
|
/**
|
|
* Computes the union of one or more arrays
|
|
* @param {...any[]} arrays One or more arrays to union
|
|
* @returns {any[]} The union of the input arrays
|
|
*/
|
|
function union(...arrays) {
|
|
return [...new Set(arrays.flat())];
|
|
}
|
|
|
|
/**
|
|
* Computes the intersection of one or more arrays
|
|
* @param {...any[]} arrays One or more arrays to intersect
|
|
* @returns {any[]} The intersection of the input arrays
|
|
*/
|
|
function intersection(...arrays) {
|
|
if (arrays.length === 0) {
|
|
return [];
|
|
}
|
|
|
|
let result = [...new Set(arrays[0])];
|
|
|
|
for (const array of arrays.slice(1)) {
|
|
result = result.filter(x => array.includes(x));
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Gets the possible types of a selector
|
|
* @param {Object} parsedSelector An object (from esquery) describing the matching behavior of the selector
|
|
* @returns {string[]|null} The node types that could possibly trigger this selector, or `null` if all node types could trigger it
|
|
*/
|
|
function getPossibleTypes(parsedSelector) {
|
|
switch (parsedSelector.type) {
|
|
case "identifier":
|
|
return [parsedSelector.value];
|
|
|
|
case "matches": {
|
|
const typesForComponents = parsedSelector.selectors.map(getPossibleTypes);
|
|
|
|
if (typesForComponents.every(Boolean)) {
|
|
return union(...typesForComponents);
|
|
}
|
|
return null;
|
|
}
|
|
|
|
case "compound": {
|
|
const typesForComponents = parsedSelector.selectors.map(getPossibleTypes).filter(typesForComponent => typesForComponent);
|
|
|
|
// If all of the components could match any type, then the compound could also match any type.
|
|
if (!typesForComponents.length) {
|
|
return null;
|
|
}
|
|
|
|
/*
|
|
* If at least one of the components could only match a particular type, the compound could only match
|
|
* the intersection of those types.
|
|
*/
|
|
return intersection(...typesForComponents);
|
|
}
|
|
|
|
case "child":
|
|
case "descendant":
|
|
case "sibling":
|
|
case "adjacent":
|
|
return getPossibleTypes(parsedSelector.right);
|
|
|
|
case "class":
|
|
if (parsedSelector.name === "function") {
|
|
return ["FunctionDeclaration", "FunctionExpression", "ArrowFunctionExpression"];
|
|
}
|
|
|
|
return null;
|
|
|
|
default:
|
|
return null;
|
|
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Counts the number of class, pseudo-class, and attribute queries in this selector
|
|
* @param {Object} parsedSelector An object (from esquery) describing the selector's matching behavior
|
|
* @returns {number} The number of class, pseudo-class, and attribute queries in this selector
|
|
*/
|
|
function countClassAttributes(parsedSelector) {
|
|
switch (parsedSelector.type) {
|
|
case "child":
|
|
case "descendant":
|
|
case "sibling":
|
|
case "adjacent":
|
|
return countClassAttributes(parsedSelector.left) + countClassAttributes(parsedSelector.right);
|
|
|
|
case "compound":
|
|
case "not":
|
|
case "matches":
|
|
return parsedSelector.selectors.reduce((sum, childSelector) => sum + countClassAttributes(childSelector), 0);
|
|
|
|
case "attribute":
|
|
case "field":
|
|
case "nth-child":
|
|
case "nth-last-child":
|
|
return 1;
|
|
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Counts the number of identifier queries in this selector
|
|
* @param {Object} parsedSelector An object (from esquery) describing the selector's matching behavior
|
|
* @returns {number} The number of identifier queries
|
|
*/
|
|
function countIdentifiers(parsedSelector) {
|
|
switch (parsedSelector.type) {
|
|
case "child":
|
|
case "descendant":
|
|
case "sibling":
|
|
case "adjacent":
|
|
return countIdentifiers(parsedSelector.left) + countIdentifiers(parsedSelector.right);
|
|
|
|
case "compound":
|
|
case "not":
|
|
case "matches":
|
|
return parsedSelector.selectors.reduce((sum, childSelector) => sum + countIdentifiers(childSelector), 0);
|
|
|
|
case "identifier":
|
|
return 1;
|
|
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Compares the specificity of two selector objects, with CSS-like rules.
|
|
* @param {ASTSelector} selectorA An AST selector descriptor
|
|
* @param {ASTSelector} selectorB Another AST selector descriptor
|
|
* @returns {number}
|
|
* a value less than 0 if selectorA is less specific than selectorB
|
|
* a value greater than 0 if selectorA is more specific than selectorB
|
|
* a value less than 0 if selectorA and selectorB have the same specificity, and selectorA <= selectorB alphabetically
|
|
* a value greater than 0 if selectorA and selectorB have the same specificity, and selectorA > selectorB alphabetically
|
|
*/
|
|
function compareSpecificity(selectorA, selectorB) {
|
|
return selectorA.attributeCount - selectorB.attributeCount ||
|
|
selectorA.identifierCount - selectorB.identifierCount ||
|
|
(selectorA.rawSelector <= selectorB.rawSelector ? -1 : 1);
|
|
}
|
|
|
|
/**
|
|
* Parses a raw selector string, and throws a useful error if parsing fails.
|
|
* @param {string} rawSelector A raw AST selector
|
|
* @returns {Object} An object (from esquery) describing the matching behavior of this selector
|
|
* @throws {Error} An error if the selector is invalid
|
|
*/
|
|
function tryParseSelector(rawSelector) {
|
|
try {
|
|
return esquery.parse(rawSelector.replace(/:exit$/u, ""));
|
|
} catch (err) {
|
|
if (err.location && err.location.start && typeof err.location.start.offset === "number") {
|
|
throw new SyntaxError(`Syntax error in selector "${rawSelector}" at position ${err.location.start.offset}: ${err.message}`);
|
|
}
|
|
throw err;
|
|
}
|
|
}
|
|
|
|
const selectorCache = new Map();
|
|
|
|
/**
|
|
* Parses a raw selector string, and returns the parsed selector along with specificity and type information.
|
|
* @param {string} rawSelector A raw AST selector
|
|
* @returns {ASTSelector} A selector descriptor
|
|
*/
|
|
function parseSelector(rawSelector) {
|
|
if (selectorCache.has(rawSelector)) {
|
|
return selectorCache.get(rawSelector);
|
|
}
|
|
|
|
const parsedSelector = tryParseSelector(rawSelector);
|
|
|
|
const result = {
|
|
rawSelector,
|
|
isExit: rawSelector.endsWith(":exit"),
|
|
parsedSelector,
|
|
listenerTypes: getPossibleTypes(parsedSelector),
|
|
attributeCount: countClassAttributes(parsedSelector),
|
|
identifierCount: countIdentifiers(parsedSelector)
|
|
};
|
|
|
|
selectorCache.set(rawSelector, result);
|
|
return result;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Public Interface
|
|
//------------------------------------------------------------------------------
|
|
|
|
/**
|
|
* The event generator for AST nodes.
|
|
* This implements below interface.
|
|
*
|
|
* ```ts
|
|
* interface EventGenerator {
|
|
* emitter: SafeEmitter;
|
|
* enterNode(node: ASTNode): void;
|
|
* leaveNode(node: ASTNode): void;
|
|
* }
|
|
* ```
|
|
*/
|
|
class NodeEventGenerator {
|
|
|
|
/**
|
|
* @param {SafeEmitter} emitter
|
|
* An SafeEmitter which is the destination of events. This emitter must already
|
|
* have registered listeners for all of the events that it needs to listen for.
|
|
* (See lib/linter/safe-emitter.js for more details on `SafeEmitter`.)
|
|
* @param {ESQueryOptions} esqueryOptions `esquery` options for traversing custom nodes.
|
|
* @returns {NodeEventGenerator} new instance
|
|
*/
|
|
constructor(emitter, esqueryOptions) {
|
|
this.emitter = emitter;
|
|
this.esqueryOptions = esqueryOptions;
|
|
this.currentAncestry = [];
|
|
this.enterSelectorsByNodeType = new Map();
|
|
this.exitSelectorsByNodeType = new Map();
|
|
this.anyTypeEnterSelectors = [];
|
|
this.anyTypeExitSelectors = [];
|
|
|
|
emitter.eventNames().forEach(rawSelector => {
|
|
const selector = parseSelector(rawSelector);
|
|
|
|
if (selector.listenerTypes) {
|
|
const typeMap = selector.isExit ? this.exitSelectorsByNodeType : this.enterSelectorsByNodeType;
|
|
|
|
selector.listenerTypes.forEach(nodeType => {
|
|
if (!typeMap.has(nodeType)) {
|
|
typeMap.set(nodeType, []);
|
|
}
|
|
typeMap.get(nodeType).push(selector);
|
|
});
|
|
return;
|
|
}
|
|
const selectors = selector.isExit ? this.anyTypeExitSelectors : this.anyTypeEnterSelectors;
|
|
|
|
selectors.push(selector);
|
|
});
|
|
|
|
this.anyTypeEnterSelectors.sort(compareSpecificity);
|
|
this.anyTypeExitSelectors.sort(compareSpecificity);
|
|
this.enterSelectorsByNodeType.forEach(selectorList => selectorList.sort(compareSpecificity));
|
|
this.exitSelectorsByNodeType.forEach(selectorList => selectorList.sort(compareSpecificity));
|
|
}
|
|
|
|
/**
|
|
* Checks a selector against a node, and emits it if it matches
|
|
* @param {ASTNode} node The node to check
|
|
* @param {ASTSelector} selector An AST selector descriptor
|
|
* @returns {void}
|
|
*/
|
|
applySelector(node, selector) {
|
|
if (esquery.matches(node, selector.parsedSelector, this.currentAncestry, this.esqueryOptions)) {
|
|
this.emitter.emit(selector.rawSelector, node);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Applies all appropriate selectors to a node, in specificity order
|
|
* @param {ASTNode} node The node to check
|
|
* @param {boolean} isExit `false` if the node is currently being entered, `true` if it's currently being exited
|
|
* @returns {void}
|
|
*/
|
|
applySelectors(node, isExit) {
|
|
const selectorsByNodeType = (isExit ? this.exitSelectorsByNodeType : this.enterSelectorsByNodeType).get(node.type) || [];
|
|
const anyTypeSelectors = isExit ? this.anyTypeExitSelectors : this.anyTypeEnterSelectors;
|
|
|
|
/*
|
|
* selectorsByNodeType and anyTypeSelectors were already sorted by specificity in the constructor.
|
|
* Iterate through each of them, applying selectors in the right order.
|
|
*/
|
|
let selectorsByTypeIndex = 0;
|
|
let anyTypeSelectorsIndex = 0;
|
|
|
|
while (selectorsByTypeIndex < selectorsByNodeType.length || anyTypeSelectorsIndex < anyTypeSelectors.length) {
|
|
if (
|
|
selectorsByTypeIndex >= selectorsByNodeType.length ||
|
|
anyTypeSelectorsIndex < anyTypeSelectors.length &&
|
|
compareSpecificity(anyTypeSelectors[anyTypeSelectorsIndex], selectorsByNodeType[selectorsByTypeIndex]) < 0
|
|
) {
|
|
this.applySelector(node, anyTypeSelectors[anyTypeSelectorsIndex++]);
|
|
} else {
|
|
this.applySelector(node, selectorsByNodeType[selectorsByTypeIndex++]);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Emits an event of entering AST node.
|
|
* @param {ASTNode} node A node which was entered.
|
|
* @returns {void}
|
|
*/
|
|
enterNode(node) {
|
|
if (node.parent) {
|
|
this.currentAncestry.unshift(node.parent);
|
|
}
|
|
this.applySelectors(node, false);
|
|
}
|
|
|
|
/**
|
|
* Emits an event of leaving AST node.
|
|
* @param {ASTNode} node A node which was left.
|
|
* @returns {void}
|
|
*/
|
|
leaveNode(node) {
|
|
this.applySelectors(node, true);
|
|
this.currentAncestry.shift();
|
|
}
|
|
}
|
|
|
|
module.exports = NodeEventGenerator;
|