cascade_layer.h | Explore in Territory

// Copyright 2021 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_CORE_CSS_CASCADE_LAYER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CASCADE_LAYER_H_

#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/css/style_rule.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/wtf/hash_set.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"

namespace blink {

// Mapping from one layer to another (obviously). This is used in two places:
//
//  - When building superrulesets, we merge the RuleSets' layers
//    to new CascadeLayer objects in the superruleset. Normally,
//    we also map values in the RuleSet::Intervals, but occasionally,
//    we need to look up @page rule etc. in the original RuleSets
//    (which are not mapped), so we need to also be able to look up
//    by the old layers, so we store and use the mapping.
//
//  - When building CascadeLayerMap (cascade_layer_map.h), we similarly combine
//    layers from all active RuleSets (the superruleset's layers
//    will be used in place of the layers of all RuleSets it is
//    subsuming), into one grouping so give them a canonical numbering.
//    For clarity, we use the typedef CanonicalLayerMap there.
LayerMap;

// A CascadeLayer object represents a node in the ordered tree of cascade layers
// in the sorted layer ordering.
// https://www.w3.org/TR/css-cascade-5/#layer-ordering
class CORE_EXPORT CascadeLayer final : public GarbageCollected<CascadeLayer> { … };

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CASCADE_LAYER_H_
chromium/third_party/blink/renderer/core/css/cascade_layer.h
