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// removeSubsets
// Given an array of nodes, remove any member that is contained by another.
exports.removeSubsets = function(nodes) {
var idx = nodes.length, node, ancestor, replace;
// Check if each node (or one of its ancestors) is already contained in the
// array.
while (--idx > -1) {
node = ancestor = nodes[idx];
// Temporarily remove the node under consideration
nodes[idx] = null;
replace = true;
while (ancestor) {
if (nodes.indexOf(ancestor) > -1) {
replace = false;
nodes.splice(idx, 1);
break;
}
ancestor = ancestor.parent;
}
// If the node has been found to be unique, re-insert it.
if (replace) {
nodes[idx] = node;
}
}
return nodes;
};
// Source: http://dom.spec.whatwg.org/#dom-node-comparedocumentposition
var POSITION = {
DISCONNECTED: 1,
PRECEDING: 2,
FOLLOWING: 4,
CONTAINS: 8,
CONTAINED_BY: 16
};
// Compare the position of one node against another node in any other document.
// The return value is a bitmask with the following values:
//
// document order:
// > There is an ordering, document order, defined on all the nodes in the
// > document corresponding to the order in which the first character of the
// > XML representation of each node occurs in the XML representation of the
// > document after expansion of general entities. Thus, the document element
// > node will be the first node. Element nodes occur before their children.
// > Thus, document order orders element nodes in order of the occurrence of
// > their start-tag in the XML (after expansion of entities). The attribute
// > nodes of an element occur after the element and before its children. The
// > relative order of attribute nodes is implementation-dependent./
// Source:
// http://www.w3.org/TR/DOM-Level-3-Core/glossary.html#dt-document-order
//
// @argument {Node} nodaA The first node to use in the comparison
// @argument {Node} nodeB The second node to use in the comparison
//
// @return {Number} A bitmask describing the input nodes' relative position.
// See http://dom.spec.whatwg.org/#dom-node-comparedocumentposition for
// a description of these values.
var comparePos = exports.compareDocumentPosition = function(nodeA, nodeB) {
var aParents = [];
var bParents = [];
var current, sharedParent, siblings, aSibling, bSibling, idx;
if (nodeA === nodeB) {
return 0;
}
current = nodeA;
while (current) {
aParents.unshift(current);
current = current.parent;
}
current = nodeB;
while (current) {
bParents.unshift(current);
current = current.parent;
}
idx = 0;
while (aParents[idx] === bParents[idx]) {
idx++;
}
if (idx === 0) {
return POSITION.DISCONNECTED;
}
sharedParent = aParents[idx - 1];
siblings = sharedParent.children;
aSibling = aParents[idx];
bSibling = bParents[idx];
if (siblings.indexOf(aSibling) > siblings.indexOf(bSibling)) {
if (sharedParent === nodeB) {
return POSITION.FOLLOWING | POSITION.CONTAINED_BY;
}
return POSITION.FOLLOWING;
} else {
if (sharedParent === nodeA) {
return POSITION.PRECEDING | POSITION.CONTAINS;
}
return POSITION.PRECEDING;
}
};
// Sort an array of nodes based on their relative position in the document and
// remove any duplicate nodes. If the array contains nodes that do not belong
// to the same document, sort order is unspecified.
//
// @argument {Array} nodes Array of DOM nodes
//
// @returns {Array} collection of unique nodes, sorted in document order
exports.uniqueSort = function(nodes) {
var idx = nodes.length, node, position;
nodes = nodes.slice();
while (--idx > -1) {
node = nodes[idx];
position = nodes.indexOf(node);
if (position > -1 && position < idx) {
nodes.splice(idx, 1);
}
}
nodes.sort(function(a, b) {
var relative = comparePos(a, b);
if (relative & POSITION.PRECEDING) {
return -1;
} else if (relative & POSITION.FOLLOWING) {
return 1;
}
return 0;
});
return nodes;
};