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Diffstat (limited to 'tools/node_modules/eslint/lib/code-path-analysis/code-path.js')
| -rw-r--r-- | tools/node_modules/eslint/lib/code-path-analysis/code-path.js | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/code-path-analysis/code-path.js b/tools/node_modules/eslint/lib/code-path-analysis/code-path.js new file mode 100644 index 0000000000..709a111189 --- /dev/null +++ b/tools/node_modules/eslint/lib/code-path-analysis/code-path.js @@ -0,0 +1,234 @@ +/** + * @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 { + + /** + * @param {string} id - An identifier. + * @param {CodePath|null} upper - The code path of the upper function scope. + * @param {Function} onLooped - A callback function to notify looping. + */ + constructor(id, upper, onLooped) { + + /** + * The identifier of this code path. + * Rules use it to store additional information of each rule. + * @type {string} + */ + this.id = id; + + /** + * 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. + * @type {CodePathSegment} + */ + get initialSegment() { + return this.internal.initialSegment; + } + + /** + * Final code path segments. + * This array is a mix of `returnedSegments` and `thrownSegments`. + * @type {CodePathSegment[]} + */ + get finalSegments() { + return this.internal.finalSegments; + } + + /** + * Final code path segments which is with `return` statements. + * This array contains the last path segment if it's reachable. + * Since the reachable last path returns `undefined`. + * @type {CodePathSegment[]} + */ + get returnedSegments() { + return this.internal.returnedForkContext; + } + + /** + * Final code path segments which is with `throw` statements. + * @type {CodePathSegment[]} + */ + get thrownSegments() { + return this.internal.thrownForkContext; + } + + /** + * Current code path segments. + * @type {CodePathSegment[]} + */ + get currentSegments() { + return this.internal.currentSegments; + } + + /** + * Traverses all segments in this code path. + * + * codePath.traverseSegments(function(segment, controller) { + * // do something. + * }); + * + * This method enumerates segments in order from the head. + * + * The `controller` object has two methods. + * + * - `controller.skip()` - Skip the following segments in this branch. + * - `controller.break()` - Skip all following segments. + * + * @param {Object} [options] - Omittable. + * @param {CodePathSegment} [options.first] - The first segment to traverse. + * @param {CodePathSegment} [options.last] - The last segment to traverse. + * @param {Function} callback - A callback function. + * @returns {void} + */ + traverseSegments(options, callback) { + if (typeof options === "function") { + callback = options; + options = null; + } + + options = options || {}; + const startSegment = options.first || this.internal.initialSegment; + const lastSegment = options.last; + + let item = null; + let index = 0; + let end = 0; + let segment = null; + const visited = Object.create(null); + const stack = [[startSegment, 0]]; + let skippedSegment = null; + let broken = false; + const controller = { + skip() { + if (stack.length <= 1) { + broken = true; + } else { + skippedSegment = stack[stack.length - 2][0]; + } + }, + break() { + broken = true; + } + }; + + /** + * Checks 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[prevSegment.id] || + segment.isLoopedPrevSegment(prevSegment) + ); + } + + while (stack.length > 0) { + item = stack[stack.length - 1]; + segment = item[0]; + index = item[1]; + + if (index === 0) { + + // Skip if this segment has been visited already. + if (visited[segment.id]) { + 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; + } + + // Reset the flag of skipping if all branches have been skipped. + if (skippedSegment && segment.prevSegments.indexOf(skippedSegment) !== -1) { + skippedSegment = null; + } + visited[segment.id] = true; + + // Call the callback when the first time. + if (!skippedSegment) { + callback.call(this, segment, controller); + if (segment === lastSegment) { + controller.skip(); + } + if (broken) { + break; + } + } + } + + // Update the stack. + end = segment.nextSegments.length - 1; + if (index < end) { + item[1] += 1; + stack.push([segment.nextSegments[index], 0]); + } else if (index === end) { + item[0] = segment.nextSegments[index]; + item[1] = 0; + } else { + stack.pop(); + } + } + } +} + +module.exports = CodePath; |