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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_SETLIKE_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_SETLIKE_H_
#include "base/containers/contains.h"
#include "third_party/blink/renderer/bindings/core/v8/iterable.h"
#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_set.h"
namespace blink {
// Utility class to simplify implementation of various `setlike` classes.
// The consumer of the class needs only to implement the |elements()| method -
// everything else should be provided by this class. For examples, see
// `XRPlaneSet` and `XRAnchorSet`.
template <typename InterfaceType, typename ElementType>
class XRSetlike : public ValueSyncIterable<InterfaceType> {
public:
unsigned size() const { return elements().size(); }
// Returns true if passed in |element| is a member of the XRSetlike.
bool hasForBinding(ScriptState* script_state,
ElementType* element,
ExceptionState& exception_state) const {
DCHECK(element);
auto all_elements = elements();
return base::Contains(all_elements, element);
}
protected:
virtual const HeapHashSet<Member<ElementType>>& elements() const = 0;
private:
class IterationSource final
: public ValueSyncIterable<InterfaceType>::IterationSource {
public:
explicit IterationSource(const HeapHashSet<Member<ElementType>>& elements)
: index_(0) {
elements_.ReserveInitialCapacity(elements.size());
for (auto element : elements) {
elements_.push_back(element);
}
}
bool FetchNextItem(ScriptState* script_state,
ElementType*& value,
ExceptionState& exception_state) override {
if (index_ >= elements_.size()) {
return false;
}
value = elements_[index_];
++index_;
return true;
}
void Trace(Visitor* visitor) const override {
visitor->Trace(elements_);
ValueSyncIterable<InterfaceType>::IterationSource::Trace(visitor);
}
private:
HeapVector<Member<ElementType>> elements_;
unsigned index_;
};
// Starts iteration over XRSetlike.
// Needed for ValueSyncIterable to work properly.
XRSetlike::IterationSource* CreateIterationSource(
ScriptState* script_state,
ExceptionState& exception_state) override {
return MakeGarbageCollected<XRSetlike::IterationSource>(elements());
}
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_SETLIKE_H_
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