mirror of
https://github.com/idanoo/GoScrobble.git
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93 lines
3.1 KiB
JavaScript
93 lines
3.1 KiB
JavaScript
/**
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* @fileoverview Define utility functions for token store.
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* @author Toru Nagashima
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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/**
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* Gets `token.range[0]` from the given token.
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* @param {Node|Token|Comment} token The token to get.
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* @returns {number} The start location.
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* @private
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*/
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function getStartLocation(token) {
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return token.range[0];
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}
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//------------------------------------------------------------------------------
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// Exports
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//------------------------------------------------------------------------------
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/**
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* Finds the index of the first token which is after the given location.
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* If it was not found, this returns `tokens.length`.
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* @param {(Token|Comment)[]} tokens It searches the token in this list.
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* @param {number} location The location to search.
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* @returns {number} The found index or `tokens.length`.
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*/
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exports.search = function search(tokens, location) {
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const index = tokens.findIndex(el => location <= getStartLocation(el));
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return index === -1 ? tokens.length : index;
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};
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/**
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* Gets the index of the `startLoc` in `tokens`.
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* `startLoc` can be the value of `node.range[1]`, so this checks about `startLoc - 1` as well.
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* @param {(Token|Comment)[]} tokens The tokens to find an index.
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* @param {Object} indexMap The map from locations to indices.
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* @param {number} startLoc The location to get an index.
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* @returns {number} The index.
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*/
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exports.getFirstIndex = function getFirstIndex(tokens, indexMap, startLoc) {
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if (startLoc in indexMap) {
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return indexMap[startLoc];
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}
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if ((startLoc - 1) in indexMap) {
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const index = indexMap[startLoc - 1];
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const token = (index >= 0 && index < tokens.length) ? tokens[index] : null;
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/*
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* For the map of "comment's location -> token's index", it points the next token of a comment.
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* In that case, +1 is unnecessary.
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*/
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if (token && token.range[0] >= startLoc) {
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return index;
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}
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return index + 1;
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}
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return 0;
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};
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/**
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* Gets the index of the `endLoc` in `tokens`.
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* The information of end locations are recorded at `endLoc - 1` in `indexMap`, so this checks about `endLoc - 1` as well.
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* @param {(Token|Comment)[]} tokens The tokens to find an index.
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* @param {Object} indexMap The map from locations to indices.
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* @param {number} endLoc The location to get an index.
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* @returns {number} The index.
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*/
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exports.getLastIndex = function getLastIndex(tokens, indexMap, endLoc) {
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if (endLoc in indexMap) {
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return indexMap[endLoc] - 1;
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}
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if ((endLoc - 1) in indexMap) {
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const index = indexMap[endLoc - 1];
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const token = (index >= 0 && index < tokens.length) ? tokens[index] : null;
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/*
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* For the map of "comment's location -> token's index", it points the next token of a comment.
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* In that case, -1 is necessary.
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*/
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if (token && token.range[1] > endLoc) {
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return index - 1;
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}
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return index;
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}
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return tokens.length - 1;
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};
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