Current File : /home/vacivi36/.trash/vacivitta/node_modules/eslint/lib/linter/code-path-analysis/code-path.js
/**
* @fileoverview A class of the code path.
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const CodePathState = require("./code-path-state");
const IdGenerator = require("./id-generator");
//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------
/**
* A code path.
*/
class CodePath {
/**
* Creates a new instance.
* @param {Object} options Options for the function (see below).
* @param {string} options.id An identifier.
* @param {string} options.origin The type of code path origin.
* @param {CodePath|null} options.upper The code path of the upper function scope.
* @param {Function} options.onLooped A callback function to notify looping.
*/
constructor({ id, origin, upper, onLooped }) {
/**
* The identifier of this code path.
* Rules use it to store additional information of each rule.
* @type {string}
*/
this.id = id;
/**
* The reason that this code path was started. May be "program",
* "function", "class-field-initializer", or "class-static-block".
* @type {string}
*/
this.origin = origin;
/**
* The code path of the upper function scope.
* @type {CodePath|null}
*/
this.upper = upper;
/**
* The code paths of nested function scopes.
* @type {CodePath[]}
*/
this.childCodePaths = [];
// Initializes internal state.
Object.defineProperty(this, "internal", {
value: new CodePathState(new IdGenerator(`${id}_`), onLooped),
});
// Adds this into `childCodePaths` of `upper`.
if (upper) {
upper.childCodePaths.push(this);
}
}
/**
* Gets the state of a given code path.
* @param {CodePath} codePath A code path to get.
* @returns {CodePathState} The state of the code path.
*/
static getState(codePath) {
return codePath.internal;
}
/**
* The initial code path segment. This is the segment that is at the head
* of the code path.
* This is a passthrough to the underlying `CodePathState`.
* @type {CodePathSegment}
*/
get initialSegment() {
return this.internal.initialSegment;
}
/**
* Final code path segments. These are the terminal (tail) segments in the
* code path, which is the combination of `returnedSegments` and `thrownSegments`.
* All segments in this array are reachable.
* This is a passthrough to the underlying `CodePathState`.
* @type {CodePathSegment[]}
*/
get finalSegments() {
return this.internal.finalSegments;
}
/**
* Final code path segments that represent normal completion of the code path.
* For functions, this means both explicit `return` statements and implicit returns,
* such as the last reachable segment in a function that does not have an
* explicit `return` as this implicitly returns `undefined`. For scripts,
* modules, class field initializers, and class static blocks, this means
* all lines of code have been executed.
* These segments are also present in `finalSegments`.
* This is a passthrough to the underlying `CodePathState`.
* @type {CodePathSegment[]}
*/
get returnedSegments() {
return this.internal.returnedForkContext;
}
/**
* Final code path segments that represent `throw` statements.
* This is a passthrough to the underlying `CodePathState`.
* These segments are also present in `finalSegments`.
* @type {CodePathSegment[]}
*/
get thrownSegments() {
return this.internal.thrownForkContext;
}
/**
* Traverses all segments in this code path.
*
* codePath.traverseSegments((segment, controller) => {
* // do something.
* });
*
* This method enumerates segments in order from the head.
*
* The `controller` argument has two methods:
*
* - `skip()` - skips the following segments in this branch
* - `break()` - skips all following segments in the traversal
*
* A note on the parameters: the `options` argument is optional. This means
* the first argument might be an options object or the callback function.
* @param {Object} [optionsOrCallback] Optional first and last segments to traverse.
* @param {CodePathSegment} [optionsOrCallback.first] The first segment to traverse.
* @param {CodePathSegment} [optionsOrCallback.last] The last segment to traverse.
* @param {Function} callback A callback function.
* @returns {void}
*/
traverseSegments(optionsOrCallback, callback) {
// normalize the arguments into a callback and options
let resolvedOptions;
let resolvedCallback;
if (typeof optionsOrCallback === "function") {
resolvedCallback = optionsOrCallback;
resolvedOptions = {};
} else {
resolvedOptions = optionsOrCallback || {};
resolvedCallback = callback;
}
// determine where to start traversing from based on the options
const startSegment =
resolvedOptions.first || this.internal.initialSegment;
const lastSegment = resolvedOptions.last;
// set up initial location information
let record;
let index;
let end;
let segment = null;
// segments that have already been visited during traversal
const visited = new Set();
// tracks the traversal steps
const stack = [[startSegment, 0]];
// segments that have been skipped during traversal
const skipped = new Set();
// indicates if we exited early from the traversal
let broken = false;
/**
* Maintains traversal state.
*/
const controller = {
/**
* Skip the following segments in this branch.
* @returns {void}
*/
skip() {
skipped.add(segment);
},
/**
* Stop traversal completely - do not traverse to any
* other segments.
* @returns {void}
*/
break() {
broken = true;
},
};
/**
* Checks if a given previous segment has been visited.
* @param {CodePathSegment} prevSegment A previous segment to check.
* @returns {boolean} `true` if the segment has been visited.
*/
function isVisited(prevSegment) {
return (
visited.has(prevSegment) ||
segment.isLoopedPrevSegment(prevSegment)
);
}
/**
* Checks if a given previous segment has been skipped.
* @param {CodePathSegment} prevSegment A previous segment to check.
* @returns {boolean} `true` if the segment has been skipped.
*/
function isSkipped(prevSegment) {
return (
skipped.has(prevSegment) ||
segment.isLoopedPrevSegment(prevSegment)
);
}
// the traversal
while (stack.length > 0) {
/*
* This isn't a pure stack. We use the top record all the time
* but don't always pop it off. The record is popped only if
* one of the following is true:
*
* 1) We have already visited the segment.
* 2) We have not visited *all* of the previous segments.
* 3) We have traversed past the available next segments.
*
* Otherwise, we just read the value and sometimes modify the
* record as we traverse.
*/
record = stack.at(-1);
segment = record[0];
index = record[1];
if (index === 0) {
// Skip if this segment has been visited already.
if (visited.has(segment)) {
stack.pop();
continue;
}
// Skip if all previous segments have not been visited.
if (
segment !== startSegment &&
segment.prevSegments.length > 0 &&
!segment.prevSegments.every(isVisited)
) {
stack.pop();
continue;
}
visited.add(segment);
// Skips the segment if all previous segments have been skipped.
const shouldSkip =
skipped.size > 0 &&
segment.prevSegments.length > 0 &&
segment.prevSegments.every(isSkipped);
/*
* If the most recent segment hasn't been skipped, then we call
* the callback, passing in the segment and the controller.
*/
if (!shouldSkip) {
resolvedCallback.call(this, segment, controller);
// exit if we're at the last segment
if (segment === lastSegment) {
controller.skip();
}
/*
* If the previous statement was executed, or if the callback
* called a method on the controller, we might need to exit the
* loop, so check for that and break accordingly.
*/
if (broken) {
break;
}
} else {
// If the most recent segment has been skipped, then mark it as skipped.
skipped.add(segment);
}
}
// Update the stack.
end = segment.nextSegments.length - 1;
if (index < end) {
/*
* If we haven't yet visited all of the next segments, update
* the current top record on the stack to the next index to visit
* and then push a record for the current segment on top.
*
* Setting the current top record's index lets us know how many
* times we've been here and ensures that the segment won't be
* reprocessed (because we only process segments with an index
* of 0).
*/
record[1] += 1;
stack.push([segment.nextSegments[index], 0]);
} else if (index === end) {
/*
* If we are at the last next segment, then reset the top record
* in the stack to next segment and set its index to 0 so it will
* be processed next.
*/
record[0] = segment.nextSegments[index];
record[1] = 0;
} else {
/*
* If index > end, that means we have no more segments that need
* processing. So, we pop that record off of the stack in order to
* continue traversing at the next level up.
*/
stack.pop();
}
}
}
}
module.exports = CodePath;
Mini Shell