/// <summary>
/// Select implementation. The public method automatically remaps a selector with the knowledge
/// that the context is external (and not part of a chain)
/// </summary>
///
/// <exception cref="ArgumentNullException">
/// Thrown when one or more required arguments are null.
/// </exception>
///
/// <param name="context">
/// The context in which the selector applies. If null, the selector is run against the entire
/// Document. If not, the selector is run against this sequence of elements.
/// </param>
///
/// <returns>
/// A list of elements. This method returns a list (rather than a sequence) because the sequence
/// must be enumerated to ensure that end-users don't cause the selector to be rerun repeatedly,
/// and that the values are not mutable (e.g. if the underlying source changes).
/// </returns>
public IList <IDomObject> Select(IEnumerable <IDomObject> context)
{
// this holds the final output
HashSet <IDomObject> output = new HashSet <IDomObject>();
if (Selector == null)
{
throw new ArgumentNullException("The selector cannot be null.");
}
if (Selector.Count == 0)
{
return(EmptyEnumerable().ToList());
}
ActiveSelectors = new List <SelectorClause>(Selector);
// First just check if we ended up here with an HTML selector; if so, hand it off.
var firstSelector = ActiveSelectors[0];
if (firstSelector.SelectorType == SelectorType.HTML)
{
return(CsQuery.Implementation.
DomDocument.Create(firstSelector.Html, HtmlParsingMode.Fragment)
.ChildNodes
.ToList());
}
// this holds any results that carried over from the previous loop for chaining
IEnumerable <IDomObject> lastResult = null;
// this is the source from which selections are made in a given iteration; it could be the DOM
// root, a context, or the previous result set.
IEnumerable <IDomObject> selectionSource = null;
// Disable the index if there is no context (e.g. disconnected elements)
// or if the first element is not indexed, or the context is not from the same document as this
// selector is bound. Determine which features can be used for this query by casting the index
// to the known interfaces.
bool useIndex;
if (context.IsNullOrEmpty())
{
useIndex = true;
}
else
{
IDomObject first = context.First();
useIndex = !first.IsDisconnected && first.IsIndexed && first.Document == Document;
}
IDomIndexRanged rangedIndex = null;
IDomIndexSimple simpleIndex = null;
if (useIndex)
{
rangedIndex = Document.DocumentIndex as IDomIndexRanged;
simpleIndex = Document.DocumentIndex as IDomIndexSimple;
}
for (activeSelectorId = 0; activeSelectorId < ActiveSelectors.Count; activeSelectorId++)
{
var selector = ActiveSelectors[activeSelectorId].Clone();
if (lastResult != null &&
(selector.CombinatorType == CombinatorType.Root || selector.CombinatorType == CombinatorType.Context))
{
// we will alter the selector during each iteration to remove the parts that have already been
// parsed, so use a copy. This is a selector that was chained with the selector grouping
// combinator "," -- we always output the results so far when beginning a new group.
output.AddRange(lastResult);
lastResult = null;
}
// For "and" combinator types, we want to leave everything as it was -- the results of this
// selector should compound with the prior. This is not an actual CSS combinator, this is the
// equivalent of grouping parenthesis. That is, in CSS there's no way to say "(input[submit],
// button):visible" - that is group the results on selector part and apply a filter to it. But
// we need to do exactly this for certain selector types (for example the jQuery :button
// selector).
if (selector.CombinatorType != CombinatorType.Grouped)
{
selectionSource = GetSelectionSource(selector, context, lastResult);
lastResult = null;
}
var key = new List <ulong>();
SelectorType removeSelectorType = 0;
// determine the type of traversal & depth for this selector
int depth = 0;
bool descendants = true;
switch (selector.TraversalType)
{
case TraversalType.Child:
depth = selector.ChildDepth;
descendants = false;
break;
case TraversalType.Filter:
case TraversalType.Adjacent:
case TraversalType.Sibling:
depth = 0;
descendants = false;
break;
case TraversalType.Descendent:
depth = 1;
descendants = true;
break;
// default: fall through with default values set above.
}
bool canUseBasicIndex = (selectionSource == null) &&
descendants &&
depth == 0;
// build index keys when possible for the active index type
if (rangedIndex != null ||
(simpleIndex != null && canUseBasicIndex) &&
!selector.NoIndex)
{
// We don't want to use the index for "NotEquals" selectors because a missing attribute
// is considered a valid match
if (selector.SelectorType.HasFlag(SelectorType.AttributeValue) &&
selector.AttributeSelectorType != AttributeSelectorType.NotExists &&
selector.AttributeSelectorType != AttributeSelectorType.NotEquals)
{
key.Add('!');
key.Add(HtmlData.Tokenize(selector.AttributeName));
// AttributeValue must still be matched manually - so remove this flag only if the
// selector is conclusive without further checking
if (selector.AttributeSelectorType == AttributeSelectorType.Exists)
{
removeSelectorType = SelectorType.AttributeValue;
}
}
else if (selector.SelectorType.HasFlag(SelectorType.Tag))
{
key.Add('+');
key.Add(HtmlData.Tokenize(selector.Tag));
removeSelectorType = SelectorType.Tag;
}
else if (selector.SelectorType.HasFlag(SelectorType.ID))
{
key.Add('#');
key.Add(HtmlData.TokenizeCaseSensitive(selector.ID));
removeSelectorType = SelectorType.ID;
}
else if (selector.SelectorType.HasFlag(SelectorType.Class))
{
key.Add('.');
key.Add(HtmlData.TokenizeCaseSensitive(selector.Class));
removeSelectorType = SelectorType.Class;
}
}
// If part of the selector was indexed, key will not be empty. Return initial set from the
// index. If any selectors remain after this they will be searched the hard way.
IEnumerable <IDomObject> result = null;
if (key.Count > 0)
{
// This is the main index access point: if we have an index key, we'll get as much as we can from the index.
// Anything else will be handled manually.
if (selectionSource == null)
{
// we don't need to test for index features at this point; if canUseBasicIndex = false and we
// are here, then the prior logic dictates that the ranged index is available. But always use
// the simple index if that's all we need because it could be faster.
result = simpleIndex.QueryIndex(key.ToArray());
}
else
{
HashSet <IDomObject> elementMatches = new HashSet <IDomObject>();
result = elementMatches;
foreach (IDomObject obj in selectionSource)
{
var subKey = key.Concat(HtmlData.indexSeparator).Concat(obj.NodePath).ToArray();
var matches = rangedIndex.QueryIndex(subKey, depth, descendants);
elementMatches.AddRange(matches);
}
}
selector.SelectorType &= ~removeSelectorType;
// Special case for attribute selectors: when Attribute Value attribute selector is present, we
// still need to filter for the correct value afterwards. But we need to change the traversal
// type because any nodes with the correct attribute type have already been selected.
if (selector.SelectorType.HasFlag(SelectorType.AttributeValue))
{
selector.TraversalType = TraversalType.Filter;
}
}
// If any selectors were not handled via the index, match them manually
if (selector.SelectorType != 0)
{
// if there are no temporary results (b/c there was no indexed selector) then use selection
// source instead (e.g. start from the same point that the index would have)
result = GetMatches(result ?? selectionSource ?? Document.ChildElements, selector);
}
lastResult = lastResult == null ?
result : lastResult.Concat(result);
}
// After the loop has finished, output any results from the last iteration.
output.AddRange(lastResult);
// Return the results as a list so that any user will not cause the selector to be run again
return(output.OrderBy(item => item.NodePath, Implementation.PathKeyComparer.Comparer).ToList());
}
/// <summary>
/// Select from the bound Document using index. First non-class/tag/id selector will result in
/// this being passed off to GetMatches.
/// </summary>
///
/// <exception cref="ArgumentNullException">
/// Thrown when one or more required arguments are null.
/// </exception>
///
/// <param name="context">
/// The context in which the selector applies. If null, the selector is run against the entire
/// Document. If not, the selector is run against this sequence of elements.
/// </param>
///
/// <returns>
/// A list of elements matching the selector.
/// </returns>
public List <IDomObject> Select(IEnumerable <IDomObject> context)
{
// this holds the final output
HashSet <IDomObject> output = new HashSet <IDomObject>();
if (Selector == null)
{
throw new ArgumentNullException("The selector cannot be null.");
}
if (Selector.Count == 0)
{
return(EmptyEnumerable().ToList());
}
ActiveSelectors = new List <SelectorClause>(Selector);
// First just check if we ended up here with an HTML selector; if so, hand it off.
var firstSelector = ActiveSelectors[0];
if (firstSelector.SelectorType == SelectorType.HTML)
{
HtmlParser.HtmlElementFactory factory =
new HtmlParser.HtmlElementFactory(firstSelector.Html);
// Return the factory ouptut as a list because otherwise the enumerator could end up
// as the actual source of the selection, meaning it would get re-parsed each time
return(factory.ParseAsFragment());
}
// this holds any results that carried over from the previous loop for chaining
IEnumerable <IDomObject> lastResult = null;
// this is the source from which selections are made in a given iteration; it could be the DOM
// root, a context, or the previous result set.
IEnumerable <IDomObject> selectionSource = null;
// Disable the index if there is no context (e.g. disconnected elements)
// or if the first element is not indexed.
bool useIndex = context.IsNullOrEmpty() ||
(!context.First().IsDisconnected&& context.First().IsIndexed);
for (activeSelectorId = 0; activeSelectorId < ActiveSelectors.Count; activeSelectorId++)
{
var selector = ActiveSelectors[activeSelectorId].Clone();
if (lastResult != null)
{
// we will alter the selector during each iteration to remove the parts that have already been
// parsed, so use a copy. This is a selector that was chained with the selector grouping
// combinator "," -- we always output the results so far when beginning a new group.
if (selector.CombinatorType == CombinatorType.Root && lastResult != null)
{
output.AddRange(lastResult);
lastResult = null;
}
}
// For "and" combinator types, we want to leave everything as it was -- the results of this
// selector should compound with the prior. This is not an actual CSS combinator, this is the
// equivalent of grouping parenthesis. That is, in CSS there's no way to say "(input[submit],
// button):visible" - that is group the results on selector part and apply a filter to it. But
// we need to do exactly this for certain selector types (for example the jQuery :button
// selector).
if (selector.CombinatorType != CombinatorType.Grouped)
{
selectionSource = GetSelectionSource(selector, context, lastResult);
lastResult = null;
}
string key = "";
SelectorType removeSelectorType = 0;
if (useIndex && !selector.NoIndex)
{
#if DEBUG_PATH
if (selector.SelectorType.HasFlag(SelectorType.AttributeValue) &&
selector.AttributeSelectorType != AttributeSelectorType.NotExists &&
selector.AttributeSelectorType != AttributeSelectorType.NotEquals)
{
key = "!" + selector.AttributeName.ToLower();
// AttributeValue must still be matched manually - so remove this flag only if the
// selector is conclusive without further checking
if (selector.AttributeSelectorType == AttributeSelectorType.Exists)
{
removeSelectorType = SelectorType.AttributeValue;
}
}
else if (selector.SelectorType.HasFlag(SelectorType.Tag))
{
key = "+" + selector.Tag.ToLower();
removeSelectorType = SelectorType.Tag;
}
else if (selector.SelectorType.HasFlag(SelectorType.ID))
{
key = "#" + selector.ID;
removeSelectorType = SelectorType.ID;
}
else if (selector.SelectorType.HasFlag(SelectorType.Class))
{
key = "." + selector.Class;
removeSelectorType = SelectorType.Class;
}
#else
// We don't want to use the index for "NotEquals" selectors because a missing attribute
// is considered a valid match
if (selector.SelectorType.HasFlag(SelectorType.AttributeValue) &&
selector.AttributeSelectorType != AttributeSelectorType.NotExists &&
selector.AttributeSelectorType != AttributeSelectorType.NotEquals)
{
key = "!" + (char)HtmlData.Tokenize(selector.AttributeName);
// AttributeValue must still be matched manually - so remove this flag only if the
// selector is conclusive without further checking
if (selector.AttributeSelectorType == AttributeSelectorType.Exists)
{
removeSelectorType = SelectorType.AttributeValue;
}
}
else if (selector.SelectorType.HasFlag(SelectorType.Tag))
{
key = "+" + (char)HtmlData.Tokenize(selector.Tag);
removeSelectorType = SelectorType.Tag;
}
else if (selector.SelectorType.HasFlag(SelectorType.ID))
{
key = "#" + (char)HtmlData.TokenizeCaseSensitive(selector.ID);
removeSelectorType = SelectorType.ID;
}
else if (selector.SelectorType.HasFlag(SelectorType.Class))
{
key = "." + (char)HtmlData.TokenizeCaseSensitive(selector.Class);
removeSelectorType = SelectorType.Class;
}
#endif
}
// If part of the selector was indexed, key will not be empty. Return initial set from the
// index. If any selectors remain after this they will be searched the hard way.
IEnumerable <IDomObject> result = null;
if (key != String.Empty)
{
// This is the main index access point: if we have an index key, we'll get as much as we can from the index.
// Anything else will be handled manually.
int depth = 0;
bool descendants = true;
switch (selector.TraversalType)
{
case TraversalType.Child:
depth = selector.ChildDepth;
descendants = false;
break;
case TraversalType.Filter:
case TraversalType.Adjacent:
case TraversalType.Sibling:
depth = 0;
descendants = false;
break;
case TraversalType.Descendent:
depth = 1;
descendants = true;
break;
}
if (selectionSource == null)
{
result = Document.DocumentIndex.QueryIndex(key + HtmlData.indexSeparator, depth, descendants);
}
else
{
HashSet <IDomObject> elementMatches = new HashSet <IDomObject>();
result = elementMatches;
foreach (IDomObject obj in selectionSource)
{
elementMatches.AddRange(Document.DocumentIndex.QueryIndex(key + HtmlData.indexSeparator + obj.Path,
depth, descendants));
}
}
selector.SelectorType &= ~removeSelectorType;
// Special case for attribute selectors: when Attribute Value attribute selector is present, we
// still need to filter for the correct value afterwards. But we need to change the traversal
// type because any nodes with the correct attribute type have already been selected.
if (selector.SelectorType.HasFlag(SelectorType.AttributeValue))
{
selector.TraversalType = TraversalType.Filter;
}
}
else if (selector.SelectorType.HasFlag(SelectorType.Elements))
{
HashSet <IDomObject> elementMatches = new HashSet <IDomObject>();
result = elementMatches;
foreach (IDomObject obj in GetAllChildOrDescendants(selector.TraversalType, selectionSource))
{
//key = HtmlData.indexSeparator + obj.Path;
HashSet <IDomObject> srcKeys = new HashSet <IDomObject>(Document.DocumentIndex.QueryIndex(HtmlData.indexSeparator + obj.Path));
foreach (IDomObject match in selector.SelectElements)
{
if (srcKeys.Contains(match))
{
elementMatches.Add(match);
}
}
}
selector.SelectorType &= ~SelectorType.Elements;
}
// If any selectors were not handled via the index, match them manually
if (selector.SelectorType != 0)
{
// if there are no temporary results (b/c there was no indexed selector) then use selection
// source instead (e.g. start from the same point that the index would have)
result = GetMatches(result ?? selectionSource ?? Document.ChildElements, selector);
}
lastResult = lastResult == null ?
result : lastResult.Concat(result);
}
// After the loop has finished, output any results from the last iteration.
output.AddRange(lastResult);
// Return the results as a list so that any user will not cause the selector to be run again
return(output.OrderBy(item => item.Path, StringComparer.Ordinal).ToList());
}
