From 99c1d9af689e5325f3cf535c4007b3aeb8325229 Mon Sep 17 00:00:00 2001 From: Minteck Date: Tue, 10 Jan 2023 14:54:04 +0100 Subject: Update - This is an automated commit --- .../node_modules/symbol-tree/lib/SymbolTreeNode.js | 54 ++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 school/node_modules/symbol-tree/lib/SymbolTreeNode.js (limited to 'school/node_modules/symbol-tree/lib/SymbolTreeNode.js') diff --git a/school/node_modules/symbol-tree/lib/SymbolTreeNode.js b/school/node_modules/symbol-tree/lib/SymbolTreeNode.js new file mode 100644 index 0000000..cae7f9a --- /dev/null +++ b/school/node_modules/symbol-tree/lib/SymbolTreeNode.js @@ -0,0 +1,54 @@ +'use strict'; + +module.exports = class SymbolTreeNode { + constructor() { + this.parent = null; + this.previousSibling = null; + this.nextSibling = null; + + this.firstChild = null; + this.lastChild = null; + + /** This value is incremented anytime a children is added or removed */ + this.childrenVersion = 0; + /** The last child object which has a cached index */ + this.childIndexCachedUpTo = null; + + /** This value represents the cached node index, as long as + * cachedIndexVersion matches with the childrenVersion of the parent */ + this.cachedIndex = -1; + this.cachedIndexVersion = NaN; // NaN is never equal to anything + } + + get isAttached() { + return Boolean(this.parent || this.previousSibling || this.nextSibling); + } + + get hasChildren() { + return Boolean(this.firstChild); + } + + childrenChanged() { + /* jshint -W016 */ + // integer wrap around + this.childrenVersion = (this.childrenVersion + 1) & 0xFFFFFFFF; + this.childIndexCachedUpTo = null; + } + + getCachedIndex(parentNode) { + // (assumes parentNode is actually the parent) + if (this.cachedIndexVersion !== parentNode.childrenVersion) { + this.cachedIndexVersion = NaN; + // cachedIndex is no longer valid + return -1; + } + + return this.cachedIndex; // -1 if not cached + } + + setCachedIndex(parentNode, index) { + // (assumes parentNode is actually the parent) + this.cachedIndexVersion = parentNode.childrenVersion; + this.cachedIndex = index; + } +}; -- cgit