// Copyright 2017 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_PROPERTIES_SHORTHAND_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_CSS_PROPERTIES_SHORTHAND_H_

#include "base/notreached.h"
#include "third_party/blink/renderer/core/css/properties/css_property.h"
#include "third_party/blink/renderer/platform/wtf/casting.h"

namespace blink {

class CSSParserContext;
class CSSParserLocalContext;
class CSSParserTokenStream;
class CSSPropertyValue;

class Shorthand : public CSSProperty {
 public:
  // Parses and consumes entire shorthand value from the token range and adds
  // all constituent parsed longhand properties to the 'properties' set.
  // Returns false if the input is invalid. (If so, all longhands added to
  // 'properties' will be removed again by the caller.)
  //
  // NOTE: This function must accept arbitrary tokens after the value,
  // without returning error. In particular, it must not check for
  // end-of-stream, since there may be “!important” after the value that
  // the caller is responsible for consuming. End-of-stream is checked
  // by the caller (after potentially consuming “!important”).
  //
  // (In practice, there are a few of these implementations that are not
  // robust against _any_ arbitrary tokens, especially those that may be
  // the start of useful values. However, they absolutely need to be
  // resistant against “!important”, at the very least.)
  virtual bool ParseShorthand(
      bool important,
      CSSParserTokenStream&,
      const CSSParserContext&,
      CSSParserLocalContext&,
      HeapVector<CSSPropertyValue, 64>& properties) const {
    NOTREACHED();
  }

 protected:
  constexpr Shorthand(CSSPropertyID id, Flags flags, char repetition_separator)
      : CSSProperty(id, flags | kShorthand, repetition_separator) {}
};

template <>
struct DowncastTraits<Shorthand> {
  static bool AllowFrom(const CSSProperty& property) {
    return property.IsShorthand();
  }
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_CSS_PROPERTIES_SHORTHAND_H_