cocos-engine/cocos/2d/utils/html-text-parser.ts

/*
 Copyright (c) 2013-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.

 https://www.cocos.com/

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated engine source code (the "Software"), a limited,
 worldwide, royalty-free, non-assignable, revocable and non-exclusive license
 to use Cocos Creator solely to develop games on your target platforms. You shall
 not use Cocos Creator software for developing other software or tools that's
 used for developing games. You are not granted to publish, distribute,
 sublicense, and/or sell copies of Cocos Creator.

 The software or tools in this License Agreement are licensed, not sold.
 Xiamen Yaji Software Co., Ltd. reserves all rights not expressly granted to you.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
*/

import { TEST } from 'internal:constants';
import { legacyCC } from '../../core/global-exports';

/**
 * @deprecated since v3.5.0, this is an engine private interface that will be removed in the future.
 */
const eventRegx = /^(click)(\s)*=|(param)(\s)*=/;
const imageAttrReg = /(\s)*src(\s)*=|(\s)*height(\s)*=|(\s)*width(\s)*=|(\s)*align(\s)*=|(\s)*offset(\s)*=|(\s)*click(\s)*=|(\s)*param(\s)*=/;

/**
 * A utils class for parsing HTML texts. The parsed results will be an object array.
 * @deprecated since v3.5.0, this is an engine private interface that will be removed in the future.
 */
export interface IHtmlTextParserResultObj{
    text?: string;
    style?: IHtmlTextParserStack;
}

/**
 * @deprecated since v3.5.0, this is an engine private interface that will be removed in the future.
 */
export interface IHtmlTextParserStack{
    color?: string;
    size?: number;
    event?: { [k: string]: string};
    isNewLine?: boolean;
    isImage?: boolean;
    src?: string;
    imageWidth?: number;
    imageHeight?: number;
    imageOffset?: string;
    imageAlign?: string;
    underline?: boolean;
    italic?: boolean;
    bold?: boolean;
    outline?: { color: string, width: number };
}

/**
 * @deprecated since v3.5.0, this is an engine private interface that will be removed in the future.
 */
export class HtmlTextParser {
    private _specialSymbolArray: Array<[RegExp, string]> = [];
    private _stack: IHtmlTextParserStack[] = [];
    private _resultObjectArray: IHtmlTextParserResultObj[] = [];

    constructor () {
        this._specialSymbolArray.push([/&lt;/g, '<']);
        this._specialSymbolArray.push([/&gt;/g, '>']);
        this._specialSymbolArray.push([/&amp;/g, '&']);
        this._specialSymbolArray.push([/&quot;/g, '"']);
        this._specialSymbolArray.push([/&apos;/g, '\'']);
    }

    public parse (htmlString: string) {
        this._resultObjectArray.length = 0;
        this._stack.length = 0;

        let startIndex = 0;
        const length = htmlString.length;
        while (startIndex < length) {
            let tagEndIndex = htmlString.indexOf('>', startIndex);
            let tagBeginIndex = -1;
            if (tagEndIndex >= 0) {
                tagBeginIndex = htmlString.lastIndexOf('<', tagEndIndex);
                const noTagBegin = tagBeginIndex < (startIndex - 1);

                if (noTagBegin) {
                    tagBeginIndex = htmlString.indexOf('<', tagEndIndex + 1);
                    tagEndIndex = htmlString.indexOf('>', tagBeginIndex + 1);
                }
            }
            if (tagBeginIndex < 0) {
                this._stack.pop();
                this._processResult(htmlString.substring(startIndex));
                startIndex = length;
            } else {
                let newStr = htmlString.substring(startIndex, tagBeginIndex);
                const tagStr = htmlString.substring(tagBeginIndex + 1, tagEndIndex);
                if (tagStr === '') newStr = htmlString.substring(startIndex, tagEndIndex + 1);
                this._processResult(newStr);
                if (tagEndIndex === -1) {
                    // cc.error('The HTML tag is invalid!');
                    tagEndIndex = tagBeginIndex;
                } else if (htmlString.charAt(tagBeginIndex + 1) === '/') {
                    this._stack.pop();
                } else {
                    this._addToStack(tagStr);
                }
                startIndex = tagEndIndex + 1;
            }
        }

        return this._resultObjectArray;
    }

    private _attributeToObject (attribute: string) {
        attribute = attribute.trim();

        const obj: IHtmlTextParserStack = {};
        let header = /^(color|size)(\s)*=/.exec(attribute);
        let tagName = '';
        let nextSpace = 0;
        let eventHanlderString = '';
        if (header) {
            tagName = header[0];
            attribute = attribute.substring(tagName.length).trim();
            if (attribute === '') {
                return obj;
            }

            // parse color
            nextSpace = attribute.indexOf(' ');
            switch (tagName[0]) {
            case 'c':
                if (nextSpace > -1) {
                    obj.color = attribute.substring(0, nextSpace).trim();
                } else {
                    obj.color = attribute;
                }
                break;
            case 's':
                obj.size = parseInt(attribute);
                break;
            default:
                break;
            }

            // tag has event arguments
            if (nextSpace > -1) {
                eventHanlderString = attribute.substring(nextSpace + 1).trim();
                obj.event = this._processEventHandler(eventHanlderString);
            }
            return obj;
        }

        header = /^(br(\s)*\/)/.exec(attribute);
        if (header && header[0].length > 0) {
            tagName = header[0].trim();
            if (tagName.startsWith('br') && tagName[tagName.length - 1] === '/') {
                obj.isNewLine = true;
                this._resultObjectArray.push({ text: '', style: { isNewLine: true } as IHtmlTextParserStack });
                return obj;
            }
        }

        header = /^(img(\s)*src(\s)*=[^>]+\/)/.exec(attribute);
        let remainingArgument = '';
        let rightQuot = -1;
        if (header && header[0].length > 0) {
            tagName = header[0].trim();
            if (tagName.startsWith('img') && tagName[tagName.length - 1] === '/') {
                header = imageAttrReg.exec(attribute);
                let tagValue;
                let isValidImageTag = false;
                while (header) {
                    // skip the invalid tags at first
                    attribute = attribute.substring(attribute.indexOf(header[0]));
                    tagName = attribute.substr(0, header[0].length);
                    // remove space and = character
                    remainingArgument = attribute.substring(tagName.length).trim();

                    rightQuot = this.getRightQuotationIndex(remainingArgument);

                    nextSpace = remainingArgument.indexOf(' ', rightQuot + 1 >= remainingArgument.length ? -1 : rightQuot + 1);

                    tagValue = (nextSpace > -1) ? remainingArgument.substr(0, nextSpace) : remainingArgument;
                    tagName = tagName.replace(/[^a-zA-Z]/g, '').trim();
                    tagName = tagName.toLowerCase();

                    attribute = remainingArgument.substring(nextSpace).trim();
                    if (tagValue.endsWith('/')) tagValue = tagValue.slice(0, -1);
                    if (tagName === 'src') {
                        switch (tagValue.charCodeAt(0)) {
                        case 34: // "
                        case 39: // '
                            isValidImageTag = true;
                            tagValue = tagValue.slice(1, -1);
                            break;
                        default:
                            break;
                        }
                        obj.isImage = true;
                        obj.src = tagValue;
                    } else if (tagName === 'height') {
                        obj.imageHeight = parseInt(tagValue);
                    } else if (tagName === 'width') {
                        obj.imageWidth = parseInt(tagValue);
                    } else if (tagName === 'align') {
                        switch (tagValue.charCodeAt(0)) {
                        case 34: // "
                        case 39: // '
                            tagValue = tagValue.slice(1, -1);
                            break;
                        default:
                            break;
                        }
                        obj.imageAlign = tagValue.toLowerCase();
                    } else if (tagName === 'offset') {
                        obj.imageOffset = tagValue;
                    } else if (tagName === 'click') {
                        obj.event = this._processEventHandler(`${tagName}=${tagValue}`);
                    }

                    if (obj.event && tagName === 'param') {
                        obj.event[tagName] = tagValue.replace(/^"|"$/g, '');
                    }

                    header = imageAttrReg.exec(attribute);
                }

                if (isValidImageTag && obj.isImage) {
                    this._resultObjectArray.push({ text: '', style: obj });
                }

                return {};
            }
        }

        header = /^(outline(\s)*[^>]*)/.exec(attribute);
        if (header) {
            attribute = header[0].substring('outline'.length).trim();
            const defaultOutlineObject = { color: '#ffffff', width: 1 };
            if (attribute) {
                const outlineAttrReg = /(\s)*color(\s)*=|(\s)*width(\s)*=|(\s)*click(\s)*=|(\s)*param(\s)*=/;
                header = outlineAttrReg.exec(attribute);
                let tagValue;
                while (header) {
                    // skip the invalid tags at first
                    attribute = attribute.substring(attribute.indexOf(header[0]));
                    tagName = attribute.substr(0, header[0].length);
                    // remove space and = character
                    remainingArgument = attribute.substring(tagName.length).trim();
                    nextSpace = remainingArgument.indexOf(' ');
                    if (nextSpace > -1) {
                        tagValue = remainingArgument.substr(0, nextSpace);
                    } else {
                        tagValue = remainingArgument;
                    }
                    tagName = tagName.replace(/[^a-zA-Z]/g, '').trim();
                    tagName = tagName.toLowerCase();

                    attribute = remainingArgument.substring(nextSpace).trim();
                    if (tagName === 'click') {
                        obj.event = this._processEventHandler(`${tagName}=${tagValue}`);
                    } else if (tagName === 'color') {
                        defaultOutlineObject.color = tagValue;
                    } else if (tagName === 'width') {
                        defaultOutlineObject.width = parseInt(tagValue);
                    }

                    if (obj.event && tagName === 'param') {
                        obj.event[tagName] = tagValue.replace(/^"|"$/g, '');
                    }

                    header = outlineAttrReg.exec(attribute);
                }
            }
            obj.outline = defaultOutlineObject;
        }

        header = /^(on|u|b|i)(\s)*/.exec(attribute);
        if (header && header[0].length > 0) {
            tagName = header[0];
            attribute = attribute.substring(tagName.length).trim();
            switch (tagName[0]) {
            case 'u':
                obj.underline = true;
                break;
            case 'i':
                obj.italic = true;
                break;
            case 'b':
                obj.bold = true;
                break;
            default:
                break;
            }
            if (attribute === '') {
                return obj;
            }

            obj.event = this._processEventHandler(attribute);
        }

        return obj;
    }

    private getRightQuotationIndex (remainingArgument: string) {
        let leftQuot = -1;
        let rightQuot = -1;
        // Skip a pair of quotations for avoiding spaces in image name are detected.
        leftQuot = remainingArgument.indexOf('\'');
        if (leftQuot > -1) {
            rightQuot = remainingArgument.indexOf('\'', leftQuot + 1 >= remainingArgument.length ? -1 : leftQuot + 1);
        } else {
            leftQuot = remainingArgument.indexOf('"');
            rightQuot = remainingArgument.indexOf('"', leftQuot + 1 >= remainingArgument.length ? -1 : leftQuot + 1);
        }

        return rightQuot;
    }

    private _processEventHandler (eventString: string) {
        const obj = {};
        let index = 0;
        let isValidTag = false;
        let eventNames = eventRegx.exec(eventString);
        while (eventNames) {
            let eventName = eventNames[0];
            let eventValue = '';
            isValidTag = false;
            eventString = eventString.substring(eventName.length).trim();
            if (eventString.charAt(0) === '"') {
                index = eventString.indexOf('"', 1);
                if (index > -1) {
                    eventValue = eventString.substring(1, index).trim();
                    isValidTag = true;
                }
                index++;
            } else if (eventString.charAt(0) === '\'') {
                index = eventString.indexOf('\'', 1);
                if (index > -1) {
                    eventValue = eventString.substring(1, index).trim();
                    isValidTag = true;
                }
                index++;
            } else {
                // skip the invalid attribute value
                const match = /(\S)+/.exec(eventString);
                if (match) {
                    eventValue = match[0];
                } else {
                    eventValue = '';
                }
                index = eventValue.length;
            }

            if (isValidTag) {
                eventName = eventName.substring(0, eventName.length - 1).trim();
                obj[eventName] = eventValue;
            }

            eventString = eventString.substring(index).trim();
            eventNames = eventRegx.exec(eventString);
        }

        return obj;
    }

    private _addToStack (attribute: string) {
        const obj = this._attributeToObject(attribute);

        if (this._stack.length === 0) {
            this._stack.push(obj);
        } else {
            if (obj.isNewLine || obj.isImage) {
                return;
            }
            // for nested tags
            const previousTagObj = this._stack[this._stack.length - 1];
            for (const key in previousTagObj) {
                if (!(obj[key])) {
                    obj[key] = previousTagObj[key];
                }
            }
            this._stack.push(obj);
        }
    }

    private _processResult (value: string) {
        if (value.length === 0) {
            return;
        }

        value = this._escapeSpecialSymbol(value);
        if (this._stack.length > 0) {
            this._resultObjectArray.push({ text: value, style: this._stack[this._stack.length - 1] });
        } else {
            this._resultObjectArray.push({ text: value } as IHtmlTextParserResultObj);
        }
    }

    private _escapeSpecialSymbol (str: string) {
        for (const symbolArr of this._specialSymbolArray) {
            const key = symbolArr[0];
            const value = symbolArr[1];

            str = str.replace(key, value);
        }

        return str;
    }
}

if (TEST) {
    legacyCC._Test.HtmlTextParser = HtmlTextParser;
}