open-element-stack.js

import * as HTML from '../common/html.js';

//Aliases
const $ = HTML.TAG_NAMES;
const NS = HTML.NAMESPACES;

//Element utils
const IMPLICIT_END_TAG_REQUIRED = new Set([$.DD, $.DT, $.LI, $.OPTGROUP, $.OPTION, $.P, $.RB, $.RP, $.RT, $.RTC]);
const IMPLICIT_END_TAG_REQUIRED_THOROUGHLY = new Set([
    ...IMPLICIT_END_TAG_REQUIRED,
    $.CAPTION,
    $.COLGROUP,
    $.TBODY,
    $.TD,
    $.TFOOT,
    $.TH,
    $.THEAD,
    $.TR,
]);
const SCOPING_ELEMENT_NS = new Map([
    [$.APPLET, NS.HTML],
    [$.CAPTION, NS.HTML],
    [$.HTML, NS.HTML],
    [$.MARQUEE, NS.HTML],
    [$.OBJECT, NS.HTML],
    [$.TABLE, NS.HTML],
    [$.TD, NS.HTML],
    [$.TEMPLATE, NS.HTML],
    [$.TH, NS.HTML],
    [$.ANNOTATION_XML, NS.MATHML],
    [$.MI, NS.MATHML],
    [$.MN, NS.MATHML],
    [$.MO, NS.MATHML],
    [$.MS, NS.MATHML],
    [$.MTEXT, NS.MATHML],
    [$.DESC, NS.SVG],
    [$.FOREIGN_OBJECT, NS.SVG],
    [$.TITLE, NS.SVG],
]);

//Stack of open elements
export class OpenElementStack {
    constructor(document, treeAdapter) {
        this.stackTop = -1;
        this.items = [];
        this.current = document;
        this.currentTagName = null;
        this.currentTmplContent = null;
        this.tmplCount = 0;
        this.treeAdapter = treeAdapter;
    }

    //Index of element
    _indexOf(element) {
        let idx = -1;

        for (let i = this.stackTop; i >= 0; i--) {
            if (this.items[i] === element) {
                idx = i;
                break;
            }
        }
        return idx;
    }

    //Update current element
    _isInTemplate() {
        return this.currentTagName === $.TEMPLATE && this.treeAdapter.getNamespaceURI(this.current) === NS.HTML;
    }

    _updateCurrentElement() {
        this.current = this.items[this.stackTop];
        this.currentTagName = this.current && this.treeAdapter.getTagName(this.current);

        this.currentTmplContent = this._isInTemplate() ? this.treeAdapter.getTemplateContent(this.current) : null;
    }

    //Mutations
    push(element) {
        this.items[++this.stackTop] = element;
        this._updateCurrentElement();

        if (this._isInTemplate()) {
            this.tmplCount++;
        }
    }

    pop() {
        this.stackTop--;

        if (this.tmplCount > 0 && this._isInTemplate()) {
            this.tmplCount--;
        }

        this._updateCurrentElement();
    }

    replace(oldElement, newElement) {
        const idx = this._indexOf(oldElement);

        this.items[idx] = newElement;

        if (idx === this.stackTop) {
            this._updateCurrentElement();
        }
    }

    insertAfter(referenceElement, newElement) {
        const insertionIdx = this._indexOf(referenceElement) + 1;

        this.items.splice(insertionIdx, 0, newElement);

        if (insertionIdx === ++this.stackTop) {
            this._updateCurrentElement();
        }
    }

    popUntilTagNamePopped(tagName) {
        while (this.stackTop > -1) {
            const tn = this.currentTagName;
            const ns = this.treeAdapter.getNamespaceURI(this.current);

            this.pop();

            if (tn === tagName && ns === NS.HTML) {
                break;
            }
        }
    }

    popUntilElementPopped(element) {
        while (this.stackTop > -1) {
            const poppedElement = this.current;

            this.pop();

            if (poppedElement === element) {
                break;
            }
        }
    }

    popUntilNumberedHeaderPopped() {
        while (this.stackTop > -1) {
            const tn = this.currentTagName;
            const ns = this.treeAdapter.getNamespaceURI(this.current);

            this.pop();

            if (
                (tn === $.H1 || tn === $.H2 || tn === $.H3 || tn === $.H4 || tn === $.H5 || tn === $.H6) &&
                ns === NS.HTML
            ) {
                break;
            }
        }
    }

    popUntilTableCellPopped() {
        while (this.stackTop > -1) {
            const tn = this.currentTagName;
            const ns = this.treeAdapter.getNamespaceURI(this.current);

            this.pop();

            if ((tn === $.TD || tn === $.TH) && ns === NS.HTML) {
                break;
            }
        }
    }

    popAllUpToHtmlElement() {
        //NOTE: here we assume that root <html> element is always first in the open element stack, so
        //we perform this fast stack clean up.
        this.stackTop = 0;
        this._updateCurrentElement();
    }

    clearBackToTableContext() {
        while (
            (this.currentTagName !== $.TABLE && this.currentTagName !== $.TEMPLATE && this.currentTagName !== $.HTML) ||
            this.treeAdapter.getNamespaceURI(this.current) !== NS.HTML
        ) {
            this.pop();
        }
    }

    clearBackToTableBodyContext() {
        while (
            (this.currentTagName !== $.TBODY &&
                this.currentTagName !== $.TFOOT &&
                this.currentTagName !== $.THEAD &&
                this.currentTagName !== $.TEMPLATE &&
                this.currentTagName !== $.HTML) ||
            this.treeAdapter.getNamespaceURI(this.current) !== NS.HTML
        ) {
            this.pop();
        }
    }

    clearBackToTableRowContext() {
        while (
            (this.currentTagName !== $.TR && this.currentTagName !== $.TEMPLATE && this.currentTagName !== $.HTML) ||
            this.treeAdapter.getNamespaceURI(this.current) !== NS.HTML
        ) {
            this.pop();
        }
    }

    remove(element) {
        for (let i = this.stackTop; i >= 0; i--) {
            if (this.items[i] === element) {
                this.items.splice(i, 1);
                this.stackTop--;
                this._updateCurrentElement();
                break;
            }
        }
    }

    //Search
    tryPeekProperlyNestedBodyElement() {
        //Properly nested <body> element (should be second element in stack).
        const element = this.items[1];

        return element && this.treeAdapter.getTagName(element) === $.BODY ? element : null;
    }

    contains(element) {
        return this._indexOf(element) > -1;
    }

    getCommonAncestor(element) {
        let elementIdx = this._indexOf(element);

        return --elementIdx >= 0 ? this.items[elementIdx] : null;
    }

    isRootHtmlElementCurrent() {
        return this.stackTop === 0 && this.currentTagName === $.HTML;
    }

    //Element in scope
    hasInScope(tagName) {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (tn === tagName && ns === NS.HTML) {
                return true;
            }

            if (SCOPING_ELEMENT_NS.get(tn) === ns) {
                return false;
            }
        }

        return true;
    }

    hasNumberedHeaderInScope() {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (
                (tn === $.H1 || tn === $.H2 || tn === $.H3 || tn === $.H4 || tn === $.H5 || tn === $.H6) &&
                ns === NS.HTML
            ) {
                return true;
            }

            if (SCOPING_ELEMENT_NS.get(tn) === ns) {
                return false;
            }
        }

        return true;
    }

    hasInListItemScope(tagName) {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (tn === tagName && ns === NS.HTML) {
                return true;
            }

            if (((tn === $.UL || tn === $.OL) && ns === NS.HTML) || SCOPING_ELEMENT_NS.get(tn) === ns) {
                return false;
            }
        }

        return true;
    }

    hasInButtonScope(tagName) {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (tn === tagName && ns === NS.HTML) {
                return true;
            }

            if ((tn === $.BUTTON && ns === NS.HTML) || SCOPING_ELEMENT_NS.get(tn) === ns) {
                return false;
            }
        }

        return true;
    }

    hasInTableScope(tagName) {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (ns !== NS.HTML) {
                continue;
            }

            if (tn === tagName) {
                return true;
            }

            if (tn === $.TABLE || tn === $.TEMPLATE || tn === $.HTML) {
                return false;
            }
        }

        return true;
    }

    hasTableBodyContextInTableScope() {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (ns !== NS.HTML) {
                continue;
            }

            if (tn === $.TBODY || tn === $.THEAD || tn === $.TFOOT) {
                return true;
            }

            if (tn === $.TABLE || tn === $.HTML) {
                return false;
            }
        }

        return true;
    }

    hasInSelectScope(tagName) {
        for (let i = this.stackTop; i >= 0; i--) {
            const tn = this.treeAdapter.getTagName(this.items[i]);
            const ns = this.treeAdapter.getNamespaceURI(this.items[i]);

            if (ns !== NS.HTML) {
                continue;
            }

            if (tn === tagName) {
                return true;
            }

            if (tn !== $.OPTION && tn !== $.OPTGROUP) {
                return false;
            }
        }

        return true;
    }

    //Implied end tags
    generateImpliedEndTags() {
        while (IMPLICIT_END_TAG_REQUIRED.has(this.currentTagName)) {
            this.pop();
        }
    }

    generateImpliedEndTagsThoroughly() {
        while (IMPLICIT_END_TAG_REQUIRED_THOROUGHLY.has(this.currentTagName)) {
            this.pop();
        }
    }

    generateImpliedEndTagsWithExclusion(exclusionTagName) {
        while (IMPLICIT_END_TAG_REQUIRED.has(this.currentTagName) && this.currentTagName !== exclusionTagName) {
            this.pop();
        }
    }
}