111 lines
4.3 KiB
JavaScript
111 lines
4.3 KiB
JavaScript
//Const
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const NOAH_ARK_CAPACITY = 3;
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export var EntryType;
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(function (EntryType) {
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EntryType[EntryType["Marker"] = 0] = "Marker";
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EntryType[EntryType["Element"] = 1] = "Element";
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})(EntryType = EntryType || (EntryType = {}));
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const MARKER = { type: EntryType.Marker };
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//List of formatting elements
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export class FormattingElementList {
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constructor(treeAdapter) {
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this.treeAdapter = treeAdapter;
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this.entries = [];
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this.bookmark = null;
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}
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//Noah Ark's condition
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//OPTIMIZATION: at first we try to find possible candidates for exclusion using
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//lightweight heuristics without thorough attributes check.
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_getNoahArkConditionCandidates(newElement, neAttrs) {
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const candidates = [];
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const neAttrsLength = neAttrs.length;
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const neTagName = this.treeAdapter.getTagName(newElement);
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const neNamespaceURI = this.treeAdapter.getNamespaceURI(newElement);
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for (let i = 0; i < this.entries.length; i++) {
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const entry = this.entries[i];
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if (entry.type === EntryType.Marker) {
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break;
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}
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const { element } = entry;
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if (this.treeAdapter.getTagName(element) === neTagName &&
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this.treeAdapter.getNamespaceURI(element) === neNamespaceURI) {
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const elementAttrs = this.treeAdapter.getAttrList(element);
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if (elementAttrs.length === neAttrsLength) {
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candidates.push({ idx: i, attrs: elementAttrs });
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}
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}
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}
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return candidates;
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}
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_ensureNoahArkCondition(newElement) {
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if (this.entries.length < NOAH_ARK_CAPACITY)
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return;
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const neAttrs = this.treeAdapter.getAttrList(newElement);
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const candidates = this._getNoahArkConditionCandidates(newElement, neAttrs);
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if (candidates.length < NOAH_ARK_CAPACITY)
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return;
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//NOTE: build attrs map for the new element, so we can perform fast lookups
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const neAttrsMap = new Map(neAttrs.map((neAttr) => [neAttr.name, neAttr.value]));
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let validCandidates = 0;
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//NOTE: remove bottommost candidates, until Noah's Ark condition will not be met
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for (let i = 0; i < candidates.length; i++) {
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const candidate = candidates[i];
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// We know that `candidate.attrs.length === neAttrs.length`
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if (candidate.attrs.every((cAttr) => neAttrsMap.get(cAttr.name) === cAttr.value)) {
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validCandidates += 1;
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if (validCandidates >= NOAH_ARK_CAPACITY) {
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this.entries.splice(candidate.idx, 1);
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}
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}
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}
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}
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//Mutations
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insertMarker() {
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this.entries.unshift(MARKER);
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}
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pushElement(element, token) {
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this._ensureNoahArkCondition(element);
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this.entries.unshift({
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type: EntryType.Element,
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element,
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token,
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});
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}
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insertElementAfterBookmark(element, token) {
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const bookmarkIdx = this.entries.indexOf(this.bookmark);
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this.entries.splice(bookmarkIdx, 0, {
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type: EntryType.Element,
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element,
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token,
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});
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}
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removeEntry(entry) {
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const entryIndex = this.entries.indexOf(entry);
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if (entryIndex >= 0) {
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this.entries.splice(entryIndex, 1);
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}
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}
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/**
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* Clears the list of formatting elements up to the last marker.
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*
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* @see https://html.spec.whatwg.org/multipage/parsing.html#clear-the-list-of-active-formatting-elements-up-to-the-last-marker
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*/
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clearToLastMarker() {
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const markerIdx = this.entries.indexOf(MARKER);
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if (markerIdx >= 0) {
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this.entries.splice(0, markerIdx + 1);
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}
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else {
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this.entries.length = 0;
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}
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}
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//Search
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getElementEntryInScopeWithTagName(tagName) {
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const entry = this.entries.find((entry) => entry.type === EntryType.Marker || this.treeAdapter.getTagName(entry.element) === tagName);
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return entry && entry.type === EntryType.Element ? entry : null;
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}
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getElementEntry(element) {
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return this.entries.find((entry) => entry.type === EntryType.Element && entry.element === element);
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}
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}
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//# sourceMappingURL=formatting-element-list.js.map
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