uBlock/src/js/arglist-parser.js

/*******************************************************************************

    uBlock Origin - a comprehensive, efficient content blocker
    Copyright (C) 2020-present Raymond Hill

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see {http://www.gnu.org/licenses/}.

    Home: https://github.com/gorhill/uBlock
*/

/******************************************************************************/

export class ArglistParser {
    constructor(separatorChar = ',', mustQuote = false) {
        this.separatorChar = this.actualSeparatorChar = separatorChar;
        this.separatorCode = this.actualSeparatorCode = separatorChar.charCodeAt(0);
        this.mustQuote = mustQuote;
        this.quoteBeg = 0; this.quoteEnd = 0;
        this.argBeg = 0; this.argEnd = 0;
        this.separatorBeg = 0; this.separatorEnd = 0;
        this.transform = false;
        this.failed = false;
        this.reWhitespaceStart = /^\s+/;
        this.reWhitespaceEnd = /(?:^|\S)(\s+)$/;
        this.reOddTrailingEscape = /(?:^|[^\\])(?:\\\\)*\\$/;
        this.reTrailingEscapeChars = /\\+$/;
    }
    nextArg(pattern, beg = 0) {
        const len = pattern.length;
        this.quoteBeg = beg + this.leftWhitespaceCount(pattern.slice(beg));
        this.failed = false;
        const qc = pattern.charCodeAt(this.quoteBeg);
        if ( qc === 0x22 /* " */ || qc === 0x27 /* ' */ || qc === 0x60 /* ` */ ) {
            this.indexOfNextArgSeparator(pattern, qc);
            if ( this.argEnd !== len ) {
                this.quoteEnd = this.argEnd + 1;
                this.separatorBeg = this.separatorEnd = this.quoteEnd;
                this.separatorEnd += this.leftWhitespaceCount(pattern.slice(this.quoteEnd));
                if ( this.separatorEnd === len ) { return this; }
                if ( pattern.charCodeAt(this.separatorEnd) === this.separatorCode ) {
                    this.separatorEnd += 1;
                    return this;
                }
            }
        }
        this.indexOfNextArgSeparator(pattern, this.separatorCode);
        this.separatorBeg = this.separatorEnd = this.argEnd;
        if ( this.separatorBeg < len ) {
            this.separatorEnd += 1;
        }
        this.argEnd -= this.rightWhitespaceCount(pattern.slice(0, this.separatorBeg));
        this.quoteEnd = this.argEnd;
        if ( this.mustQuote ) {
            this.failed = true;
        }
        return this;
    }
    normalizeArg(s, char = '') {
        if ( char === '' ) { char = this.actualSeparatorChar; }
        let out = '';
        let pos = 0;
        while ( (pos = s.lastIndexOf(char)) !== -1 ) {
            out = s.slice(pos) + out;
            s = s.slice(0, pos);
            const match = this.reTrailingEscapeChars.exec(s);
            if ( match === null ) { continue; }
            const tail = (match[0].length & 1) !== 0
                ? match[0].slice(0, -1)
                : match[0];
            out = tail + out;
            s = s.slice(0, -match[0].length);
        }
        if ( out === '' ) { return s; }
        return s + out;
    }
    leftWhitespaceCount(s) {
        const match = this.reWhitespaceStart.exec(s);
        return match === null ? 0 : match[0].length;
    }
    rightWhitespaceCount(s) {
        const match = this.reWhitespaceEnd.exec(s);
        return match === null ? 0 : match[1].length;
    }
    indexOfNextArgSeparator(pattern, separatorCode) {
        this.argBeg = this.argEnd = separatorCode !== this.separatorCode
            ? this.quoteBeg + 1
            : this.quoteBeg;
        this.transform = false;
        if ( separatorCode !== this.actualSeparatorCode ) {
            this.actualSeparatorCode = separatorCode;
            this.actualSeparatorChar = String.fromCharCode(separatorCode);
        }
        while ( this.argEnd < pattern.length ) {
            const pos = pattern.indexOf(this.actualSeparatorChar, this.argEnd);
            if ( pos === -1 ) {
                return (this.argEnd = pattern.length);
            }
            if ( this.reOddTrailingEscape.test(pattern.slice(0, pos)) === false ) {
                return (this.argEnd = pos);
            }
            this.transform = true;
            this.argEnd = pos + 1;
        }
    }
}