/// <summary>
/// Return all elements matching a selector, within a domain baseList, starting from list.
/// </summary>
/// <param name="baseList"></param>
/// <param name="list"></param>
/// <param name="selector"></param>
/// <returns></returns>
protected IEnumerable<IDomObject> GetMatches(IEnumerable<IDomObject> list, Selector selector)
{
// Maintain a hashset of every element already searched. Since result sets frequently contain items which are
// children of other items in the list, we would end up searching the tree repeatedly
HashSet<IDomObject> uniqueElements = null;
Stack<MatchElement> stack = null;
IEnumerable<IDomObject> curList = list;
HashSet<IDomObject> temporaryResults = new HashSet<IDomObject>();
// The unique list has to be reset for each sub-selector
uniqueElements = new HashSet<IDomObject>();
if (selector.SelectorType == SelectorType.HTML)
{
HtmlParser.DomElementFactory factory = new HtmlParser.DomElementFactory(Document);
foreach (var obj in factory.CreateObjects(selector.Html))
{
yield return obj;
}
yield break;
}
// Result-list position selectors are simple -- skip out of main matching code if so
if (selector.SelectorType.HasFlag(SelectorType.Position) && selector.IsResultListPosition)
{
foreach (var obj in GetResultPositionMatches(curList, selector))
{
yield return obj;
}
yield break;
}
// Otherwise, try to match each element individually
stack = new Stack<MatchElement>();
foreach (var e in curList)
{
// We must check everything again when looking for specific depth of children
// otherwise - no point - skip em
if (selector.TraversalType != TraversalType.Child && uniqueElements.Contains(e))
{
continue;
}
stack.Push(new MatchElement(e, 0));
int matchIndex = 0;
while (stack.Count != 0)
{
var current = stack.Pop();
if (Matches(selector, current.Object, current.Depth))
{
temporaryResults.Add(current.Object);
matchIndex++;
}
// Add children to stack (in reverse order, so they are processed in the correct order when popped)
// Don't keep going to children if the target depth is < the depth. Though the match would still fail,
// stuff would end up the unique list which we might need to test later if it appears directly in the source list
// causing it to be ignored.
if (selector.TraversalType != TraversalType.Filter &&
current.Object is IDomElement &&
(selector.TraversalType != TraversalType.Child || selector.ChildDepth > current.Depth))
{
SelectorType selectorType = selector.SelectorType;
IDomElement elm = current.Element;
if (selector.TraversalType == TraversalType.Child
&& selector.ChildDepth == current.Depth + 1
&& selector.IsDomIndexPosition)
{
temporaryResults.AddRange(GetDomPositionMatches(elm, selector));
selectorType &= ~SelectorType.Position;
}
if (selectorType == 0)
{
continue;
}
for (int j = elm.ChildNodes.Count - 1; j >= 0; j--)
{
IDomObject obj = elm[j];
if (selector.TraversalType == TraversalType.Child && !uniqueElements.Add(obj))
{
continue;
}
if (obj.NodeType == NodeType.ELEMENT_NODE)
{
stack.Push(new MatchElement(obj, current.Depth + 1));
}
}
}
}
}
foreach (var obj in temporaryResults)
{
yield return obj;
}
yield break;
}
/// <summary>
/// Return all elements matching a selector, within a domain baseList, starting from list.
/// </summary>
/// <param name="baseList"></param>
/// <param name="list"></param>
/// <param name="selector"></param>
/// <returns></returns>
protected IEnumerable <IDomObject> GetMatches(IEnumerable <IDomObject> list, Selector selector)
{
// Maintain a hashset of every element already searched. Since result sets frequently contain items which are
// children of other items in the list, we would end up searching the tree repeatedly
HashSet <IDomObject> uniqueElements = null;
Stack <MatchElement> stack = null;
IEnumerable <IDomObject> curList = list;
HashSet <IDomObject> temporaryResults = new HashSet <IDomObject>();
// The unique list has to be reset for each sub-selector
uniqueElements = new HashSet <IDomObject>();
if (selector.SelectorType == SelectorType.HTML)
{
HtmlParser.DomElementFactory factory = new HtmlParser.DomElementFactory(Document);
foreach (var obj in factory.CreateObjects(selector.Html))
{
yield return(obj);
}
yield break;
}
// Result-list position selectors are simple -- skip out of main matching code if so
if (selector.SelectorType.HasFlag(SelectorType.Position) && selector.IsResultListPosition)
{
foreach (var obj in GetResultPositionMatches(curList, selector))
{
yield return(obj);
}
yield break;
}
// Otherwise, try to match each element individually
stack = new Stack <MatchElement>();
foreach (var e in curList)
{
// We must check everything again when looking for specific depth of children
// otherwise - no point - skip em
if (selector.TraversalType != TraversalType.Child && uniqueElements.Contains(e))
{
continue;
}
stack.Push(new MatchElement(e, 0));
int matchIndex = 0;
while (stack.Count != 0)
{
var current = stack.Pop();
if (Matches(selector, current.Object, current.Depth))
{
temporaryResults.Add(current.Object);
matchIndex++;
}
// Add children to stack (in reverse order, so they are processed in the correct order when popped)
// Don't keep going to children if the target depth is < the depth. Though the match would still fail,
// stuff would end up the unique list which we might need to test later if it appears directly in the source list
// causing it to be ignored.
if (selector.TraversalType != TraversalType.Filter &&
current.Object is IDomElement &&
(selector.TraversalType != TraversalType.Child || selector.ChildDepth > current.Depth))
{
SelectorType selectorType = selector.SelectorType;
IDomElement elm = current.Element;
if (selector.TraversalType == TraversalType.Child &&
selector.ChildDepth == current.Depth + 1 &&
selector.IsDomIndexPosition)
{
temporaryResults.AddRange(GetDomPositionMatches(elm, selector));
selectorType &= ~SelectorType.Position;
}
if (selectorType == 0)
{
continue;
}
for (int j = elm.ChildNodes.Count - 1; j >= 0; j--)
{
IDomObject obj = elm[j];
if (selector.TraversalType == TraversalType.Child && !uniqueElements.Add(obj))
{
continue;
}
if (obj.NodeType == NodeType.ELEMENT_NODE)
{
stack.Push(new MatchElement(obj, current.Depth + 1));
}
}
}
}
}
foreach (var obj in temporaryResults)
{
yield return(obj);
}
yield break;
}
