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/*
* Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
* Copyright (C) 2006, 2009 Apple Inc.
* Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "third_party/blink/renderer/core/xml/xpath_path.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/dom/node_traversal.h"
#include "third_party/blink/renderer/core/xml/xpath_predicate.h"
#include "third_party/blink/renderer/core/xml/xpath_step.h"
#include "third_party/blink/renderer/core/xml/xpath_value.h"
namespace blink {
namespace xpath {
Filter::Filter(Expression* expr, GCedHeapVector<Member<Predicate>>& predicates)
: expr_(expr) {
predicates_.swap(predicates);
SetIsContextNodeSensitive(expr_->IsContextNodeSensitive());
SetIsContextPositionSensitive(expr_->IsContextPositionSensitive());
SetIsContextSizeSensitive(expr_->IsContextSizeSensitive());
}
Filter::~Filter() = default;
void Filter::Trace(Visitor* visitor) const {
visitor->Trace(expr_);
visitor->Trace(predicates_);
Expression::Trace(visitor);
}
Value Filter::Evaluate(EvaluationContext& evaluation_context) const {
Value v = expr_->Evaluate(evaluation_context);
NodeSet& nodes = v.ModifiableNodeSet(evaluation_context);
nodes.Sort();
for (const auto& predicate : predicates_) {
NodeSet* new_nodes = NodeSet::Create();
evaluation_context.size = nodes.size();
evaluation_context.position = 0;
for (const auto& node : nodes) {
evaluation_context.node = node;
++evaluation_context.position;
if (predicate->Evaluate(evaluation_context))
new_nodes->Append(node);
}
nodes.Swap(*new_nodes);
}
return v;
}
LocationPath::LocationPath() : absolute_(false) {
SetIsContextNodeSensitive(true);
}
LocationPath::~LocationPath() = default;
void LocationPath::Trace(Visitor* visitor) const {
visitor->Trace(steps_);
Expression::Trace(visitor);
}
Value LocationPath::Evaluate(EvaluationContext& evaluation_context) const {
EvaluationContext cloned_context = evaluation_context;
// http://www.w3.org/TR/xpath/
// Section 2, Location Paths:
// "/ selects the document root (which is always the parent of the document
// element)"
// "A / by itself selects the root node of the document containing the context
// node."
// In the case of a tree that is detached from the document, we violate
// the spec and treat / as the root node of the detached tree.
// This is for compatibility with Firefox, and also seems like a more
// logical treatment of where you would expect the "root" to be.
Node* context = evaluation_context.node;
if (absolute_ && context->getNodeType() != Node::kDocumentNode) {
if (context->isConnected())
context = context->ownerDocument();
else
context = &NodeTraversal::HighestAncestorOrSelf(*context);
}
NodeSet* nodes = NodeSet::Create();
nodes->Append(context);
Evaluate(cloned_context, *nodes);
return Value(nodes, Value::kAdopt);
}
void LocationPath::Evaluate(EvaluationContext& context, NodeSet& nodes) const {
bool result_is_sorted = nodes.IsSorted();
for (const auto& step : steps_) {
NodeSet* new_nodes = NodeSet::Create();
HeapHashSet<Member<Node>> new_nodes_set;
bool need_to_check_for_duplicate_nodes =
!nodes.SubtreesAreDisjoint() ||
(step->GetAxis() != Step::kChildAxis &&
step->GetAxis() != Step::kSelfAxis &&
step->GetAxis() != Step::kDescendantAxis &&
step->GetAxis() != Step::kDescendantOrSelfAxis &&
step->GetAxis() != Step::kAttributeAxis);
if (need_to_check_for_duplicate_nodes)
result_is_sorted = false;
// This is a simplified check that can be improved to handle more cases.
if (nodes.SubtreesAreDisjoint() && (step->GetAxis() == Step::kChildAxis ||
step->GetAxis() == Step::kSelfAxis))
new_nodes->MarkSubtreesDisjoint(true);
for (const auto& input_node : nodes) {
NodeSet* matches = NodeSet::Create();
step->Evaluate(context, input_node, *matches);
if (!matches->IsSorted())
result_is_sorted = false;
for (const auto& node : *matches) {
if (!need_to_check_for_duplicate_nodes ||
new_nodes_set.insert(node).is_new_entry)
new_nodes->Append(node);
}
}
nodes.Swap(*new_nodes);
}
nodes.MarkSorted(result_is_sorted);
}
void LocationPath::AppendStep(Step* step) {
unsigned step_count = steps_.size();
if (step_count && OptimizeStepPair(steps_[step_count - 1], step))
return;
step->Optimize();
steps_.push_back(step);
}
void LocationPath::InsertFirstStep(Step* step) {
if (steps_.size() && OptimizeStepPair(step, steps_[0])) {
steps_[0] = step;
return;
}
step->Optimize();
steps_.insert(0, step);
}
Path::Path(Expression* filter, LocationPath* path)
: filter_(filter), path_(path) {
SetIsContextNodeSensitive(filter->IsContextNodeSensitive());
SetIsContextPositionSensitive(filter->IsContextPositionSensitive());
SetIsContextSizeSensitive(filter->IsContextSizeSensitive());
}
Path::~Path() = default;
void Path::Trace(Visitor* visitor) const {
visitor->Trace(filter_);
visitor->Trace(path_);
Expression::Trace(visitor);
}
Value Path::Evaluate(EvaluationContext& context) const {
Value v = filter_->Evaluate(context);
NodeSet& nodes = v.ModifiableNodeSet(context);
path_->Evaluate(context, nodes);
return v;
}
} // namespace xpath
} // namespace blink
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