sousa-gecko/layout/style/ServoCSSParser.h

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* CSS parsing utility functions */

#ifndef mozilla_ServoCSSParser_h
#define mozilla_ServoCSSParser_h

#include "NonCustomCSSPropertyId.h"
#include "mozilla/AlreadyAddRefed.h"
#include "mozilla/gfx/Matrix.h"
#include "nsColor.h"
#include "nsDOMCSSDeclaration.h"
#include "nsStringFwd.h"

struct nsCSSRect;
template <class T>
class RefPtr;

namespace mozilla {

struct CSSPropertyId;
class ServoStyleSet;
struct URLExtraData;
struct StyleAbsoluteColor;
struct StyleFontFamilyList;
struct StyleFontStretch;
struct StyleFontWeight;
struct StyleFontStyle;
struct StyleLockedDeclarationBlock;
struct StyleParsingMode;
struct StylePerDocumentStyleData;
enum class StyleColorSpace : uint8_t;

template <typename Integer, typename Number, typename LinearStops>
struct StyleTimingFunction;
struct StylePiecewiseLinearFunction;
using StyleComputedTimingFunction =
    StyleTimingFunction<int32_t, float, StylePiecewiseLinearFunction>;

template <typename LengthPercent>
struct StyleGenericViewTimelineInset;
struct StyleLengthPercentage;
using StyleViewTimelineInset =
    StyleGenericViewTimelineInset<StyleLengthPercentage>;

namespace css {
class Loader;
}

namespace dom {
class Document;
}

class ServoCSSParser {
 public:
  using ParsingEnvironment = nsDOMCSSDeclaration::ParsingEnvironment;

  /**
   * Returns whether the specified string can be parsed as a valid CSS
   * <color> value.
   *
   * This includes Mozilla-specific keywords such as -moz-default-color.
   */
  static bool IsValidCSSColor(const nsACString& aValue);

  /**
   * Returns whether the specified string can be parsed as a valid CSS
   * <image> value.
   */
  static bool IsValidCSSImage(const nsACString& aValue);

  /**
   * Computes an nscolor from the given CSS <color> value.
   *
   * @param aStyleData The style data to compute system colors and other special
   *   color values.
   * @param aCurrentColor The color value that currentcolor should compute to.
   * @param aValue The CSS <color> value.
   * @param aResultColor The resulting computed color value.
   * @param aWasCurrentColor Whether aValue was currentcolor. Can be nullptr
   *   if the caller doesn't care.
   * @param aLoader The CSS loader for document we're parsing a color for,
   *   so that parse errors can be reported to the console. If nullptr, errors
   *   won't be reported to the console.
   * @return Whether aValue was successfully parsed and aResultColor was set.
   */
  static bool ComputeColor(const StylePerDocumentStyleData* aStyleData,
                           nscolor aCurrentColor, const nsACString& aValue,
                           nscolor* aResultColor,
                           bool* aWasCurrentColor = nullptr,
                           css::Loader* aLoader = nullptr);

  /**
   * Computes a StyleAbsoluteColor from the given CSS <color> value.
   *
   * @param aStyleData The style data to compute system colors and other special
   *   color values.
   * @param aValue The CSS <color> value.
   * @return The resulting computed color value. For invalid color value,
   *   Nothing() will be returned.
   */
  static Maybe<StyleAbsoluteColor> ComputeAbsoluteColor(
      const StylePerDocumentStyleData* aStyleData, const nsACString& aValue);

  /**
  * Takes a CSS <color> and convert it to another color space.
  *
  * @param aStyleSet The style set whose nsPresContext will be used to
  *   compute system colors and other special color values.
  * @param aFromColor The CSS <color> we use to convert from.
  * @param aToColorSpace The CSS <color-space> to convert the color into.
  * @param aResultColor The resulting converted color value.
  * @param aResultAdjusted Whether the color was adjusted to fit into the SRGB
      color space.
  * @param aLoader The CSS loader for document we're parsing a color for,
  *   so that parse errors can be reported to the console. If nullptr, errors
  *   won't be reported to the console.
  * @return Whether aFromColor and aToColorSpace was successfully parsed and
  *   aResultColor and aResultAdjusted was set.
  */
  static bool ColorTo(const nsACString& aFromColor,
                      const nsACString& aToColorSpace, nsACString* aResultColor,
                      nsTArray<float>* aResultComponents, bool* aResultAdjusted,
                      css::Loader* aLoader = nullptr);

  /**
   * Parse a string representing a CSS property value into a
   * StyleLockedDeclarationBlock.
   *
   * @param aProperty The property to be parsed.
   * @param aValue The specified value.
   * @param aParsingEnvironment All the parsing environment data we need.
   * @param aParsingMode The parsing mode we apply.
   * @return The parsed value as a StyleLockedDeclarationBlock. We put the value
   *   in a declaration block since that is how we represent specified values
   *   in Servo.
   */
  static already_AddRefed<StyleLockedDeclarationBlock> ParseProperty(
      NonCustomCSSPropertyId aProperty, const nsACString& aValue,
      const ParsingEnvironment& aParsingEnvironment,
      const StyleParsingMode& aParsingMode);
  static already_AddRefed<StyleLockedDeclarationBlock> ParseProperty(
      const CSSPropertyId& aProperty, const nsACString& aValue,
      const ParsingEnvironment& aParsingEnvironment,
      const StyleParsingMode& aParsingMode);

  /**
   * Parse an animation timing function.
   *
   * @param aValue The specified value.
   * @param aResult The output timing function. (output)
   * @return Whether the value was successfully parsed.
   */
  static bool ParseEasing(const nsACString& aValue,
                          StyleComputedTimingFunction& aResult);

  /**
   * Parse a view timeline inset, as the syntax of <view-timeline-inset>, and
   * then compute it as StyleViewTimelineInset.
   * https://drafts.csswg.org/scroll-animations-1/#view-timeline-inset
   *
   * @param aValue The specified value.
   * @param aSubject The subject element of the view timeline.
   * @param aStyle The style of the subject element.
   * @param aRawData The style data of the document.
   * @param aResult The output view timeline inset. (output)
   * @return Whether the value was successfully parsed.
   */
  static bool ParseAndComputeViewTimelineInset(
      const nsACString& aValue, const dom::Element* aSubject,
      const ComputedStyle* aStyle, const StylePerDocumentStyleData* aRawData,
      StyleViewTimelineInset& aResult);

  /**
   * Parse a specified transform list into a gfx matrix.
   *
   * @param aValue The specified value.
   * @param aContains3DTransform The output flag indicates whether this is any
   *   3d transform function. (output)
   * @param aResult The output matrix. (output)
   * @return Whether the value was successfully parsed.
   */
  static bool ParseTransformIntoMatrix(const nsACString& aValue,
                                       bool& aContains3DTransform,
                                       gfx::Matrix4x4& aResult);

  /**
   * Parse a font shorthand for FontFaceSet matching, so we only care about
   * FontFamily, FontStyle, FontStretch, and FontWeight.
   *
   * @param aValue The specified value.
   * @param aUrl The parser url extra data.
   * @param aList The parsed FontFamily list. (output)
   * @param aStyle The parsed FontStyle. (output)
   * @param aStretch The parsed FontStretch. (output)
   * @param aWeight The parsed FontWeight. (output)
   * @param aSize If non-null, returns the parsed font size. (output)
   * @param aSmallCaps If non-null, whether small-caps was specified (output)
   * @return Whether the value was successfully parsed.
   */
  static bool ParseFontShorthandForMatching(
      const nsACString& aValue, URLExtraData* aUrl, StyleFontFamilyList& aList,
      StyleFontStyle& aStyle, StyleFontStretch& aStretch,
      StyleFontWeight& aWeight, float* aSize = nullptr,
      bool* aSmallCaps = nullptr);

  /**
   * Get a URLExtraData from a document.
   */
  static already_AddRefed<URLExtraData> GetURLExtraData(dom::Document*);

  /**
   * Get a ParsingEnvironment from a document.
   */
  static ParsingEnvironment GetParsingEnvironment(dom::Document*);
};

}  // namespace mozilla

#endif  // mozilla_ServoCSSParser_h