"use strict";
/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.findUrls = findUrls;
// TODO: Combine everything into a single pass lexer
/**
 * Determines if a unicode code point is a CSS whitespace character.
 * @param code The unicode code point to test.
 * @returns true, if the code point is CSS whitespace; false, otherwise.
 */
function isWhitespace(code) {
    // Based on https://www.w3.org/TR/css-syntax-3/#whitespace
    switch (code) {
        case 0x0009: // tab
        case 0x0020: // space
        case 0x000a: // line feed
        case 0x000c: // form feed
        case 0x000d: // carriage return
            return true;
        default:
            return false;
    }
}
/**
 * Scans a CSS or Sass file and locates all valid url function values as defined by the
 * syntax specification.
 * @param contents A string containing a CSS or Sass file to scan.
 * @returns An iterable that yields each CSS url function value found.
 */
function* findUrls(contents) {
    let pos = 0;
    let width = 1;
    let current = -1;
    const next = () => {
        pos += width;
        current = contents.codePointAt(pos) ?? -1;
        width = current > 0xffff ? 2 : 1;
        return current;
    };
    // Based on https://www.w3.org/TR/css-syntax-3/#consume-ident-like-token
    while ((pos = contents.indexOf('url(', pos)) !== -1) {
        width = 1;
        // Ensure whitespace, comma, or colon before `url(`
        if (pos > 0) {
            pos -= 2;
            next();
            if (!isWhitespace(current) && current !== 0x002c && current !== 0x003a) {
                // Skip - not a url token
                pos += 3;
                continue;
            }
            pos += 1;
        }
        // Set to position of the (
        pos += 3;
        // Consume all leading whitespace
        while (isWhitespace(next())) {
            /* empty */
        }
        // Initialize URL state
        const url = { start: pos, end: -1, value: '' };
        let complete = false;
        // If " or ', then consume the value as a string
        if (current === 0x0022 || current === 0x0027) {
            const ending = current;
            // Based on https://www.w3.org/TR/css-syntax-3/#consume-string-token
            while (!complete) {
                switch (next()) {
                    case -1: // EOF
                        return;
                    case 0x000a: // line feed
                    case 0x000c: // form feed
                    case 0x000d: // carriage return
                        // Invalid
                        complete = true;
                        break;
                    case 0x005c: // \ -- character escape
                        // If not EOF or newline, add the character after the escape
                        switch (next()) {
                            case -1:
                                return;
                            case 0x000a: // line feed
                            case 0x000c: // form feed
                            case 0x000d: // carriage return
                                // Skip when inside a string
                                break;
                            default:
                                // TODO: Handle hex escape codes
                                url.value += String.fromCodePoint(current);
                                break;
                        }
                        break;
                    case ending:
                        // Full string position should include the quotes for replacement
                        url.end = pos + 1;
                        complete = true;
                        yield url;
                        break;
                    default:
                        url.value += String.fromCodePoint(current);
                        break;
                }
            }
            next();
            continue;
        }
        // Based on https://www.w3.org/TR/css-syntax-3/#consume-url-token
        while (!complete) {
            switch (current) {
                case -1: // EOF
                    return;
                case 0x0022: // "
                case 0x0027: // '
                case 0x0028: // (
                    // Invalid
                    complete = true;
                    break;
                case 0x0029: // )
                    // URL is valid and complete
                    url.end = pos;
                    complete = true;
                    break;
                case 0x005c: // \ -- character escape
                    // If not EOF or newline, add the character after the escape
                    switch (next()) {
                        case -1: // EOF
                            return;
                        case 0x000a: // line feed
                        case 0x000c: // form feed
                        case 0x000d: // carriage return
                            // Invalid
                            complete = true;
                            break;
                        default:
                            // TODO: Handle hex escape codes
                            url.value += String.fromCodePoint(current);
                            break;
                    }
                    break;
                default:
                    if (isWhitespace(current)) {
                        while (isWhitespace(next())) {
                            /* empty */
                        }
                        // Unescaped whitespace is only valid before the closing )
                        if (current === 0x0029) {
                            // URL is valid
                            url.end = pos;
                        }
                        complete = true;
                    }
                    else {
                        // Add the character to the url value
                        url.value += String.fromCodePoint(current);
                    }
                    break;
            }
            next();
        }
        // An end position indicates a URL was found
        if (url.end !== -1) {
            yield url;
        }
    }
}
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