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diff --git a/dom/svg/SVGContentUtils.h b/dom/svg/SVGContentUtils.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef DOM_SVG_SVGCONTENTUTILS_H_
+#define DOM_SVG_SVGCONTENTUTILS_H_
+
+// include math.h to pick up definition of M_ maths defines e.g. M_PI
+#include <math.h>
+
+#include "mozilla/gfx/2D.h"  // for StrokeOptions
+#include "mozilla/gfx/Matrix.h"
+#include "mozilla/RangedPtr.h"
+#include "nsError.h"
+#include "nsStringFwd.h"
+#include "nsTArray.h"
+#include "gfx2DGlue.h"
+#include "nsDependentSubstring.h"
+
+class nsIContent;
+
+class nsIFrame;
+class nsPresContext;
+
+namespace mozilla {
+class ComputedStyle;
+class SVGAnimatedTransformList;
+class SVGAnimatedPreserveAspectRatio;
+class SVGContextPaint;
+class SVGPreserveAspectRatio;
+union StyleLengthPercentageUnion;
+namespace dom {
+class Document;
+class Element;
+class SVGElement;
+class SVGSVGElement;
+class SVGViewportElement;
+}  // namespace dom
+
+#define SVG_ZERO_LENGTH_PATH_FIX_FACTOR 512
+
+/**
+ * SVGTransformTypes controls the transforms that PrependLocalTransformsTo
+ * applies.
+ *
+ * If aWhich is eAllTransforms, then all the transforms from the coordinate
+ * space established by this element for its children to the coordinate
+ * space established by this element's parent element for this element, are
+ * included.
+ *
+ * If aWhich is eUserSpaceToParent, then only the transforms from this
+ * element's userspace to the coordinate space established by its parent is
+ * included. This includes any transforms introduced by the 'transform'
+ * attribute, transform animations and animateMotion, but not any offsets
+ * due to e.g. 'x'/'y' attributes, or any transform due to a 'viewBox'
+ * attribute. (SVG userspace is defined to be the coordinate space in which
+ * coordinates on an element apply.)
+ *
+ * If aWhich is eChildToUserSpace, then only the transforms from the
+ * coordinate space established by this element for its childre to this
+ * elements userspace are included. This includes any offsets due to e.g.
+ * 'x'/'y' attributes, and any transform due to a 'viewBox' attribute, but
+ * does not include any transforms due to the 'transform' attribute.
+ */
+enum SVGTransformTypes {
+  eAllTransforms,
+  eUserSpaceToParent,
+  eChildToUserSpace
+};
+
+/**
+ * Functions generally used by SVG Content classes. Functions here
+ * should not generally depend on layout methods/classes e.g. SVGUtils
+ */
+class SVGContentUtils {
+ public:
+  using Float = gfx::Float;
+  using Matrix = gfx::Matrix;
+  using Rect = gfx::Rect;
+  using StrokeOptions = gfx::StrokeOptions;
+
+  /*
+   * Get the outer SVG element of an nsIContent
+   */
+  static dom::SVGSVGElement* GetOuterSVGElement(dom::SVGElement* aSVGElement);
+
+  /**
+   * Moz2D's StrokeOptions requires someone else to own its mDashPattern
+   * buffer, which is a pain when you want to initialize a StrokeOptions object
+   * in a helper function and pass it out. This sub-class owns the mDashPattern
+   * buffer so that consumers of such a helper function don't need to worry
+   * about creating it, passing it in, or deleting it. (An added benefit is
+   * that in the typical case when stroke-dasharray is short it will avoid
+   * allocating.)
+   */
+  struct AutoStrokeOptions : public StrokeOptions {
+    AutoStrokeOptions() {
+      MOZ_ASSERT(mDashLength == 0, "InitDashPattern() depends on this");
+    }
+    ~AutoStrokeOptions() {
+      if (mDashPattern && mDashPattern != mSmallArray) {
+        delete[] mDashPattern;
+      }
+    }
+    /**
+     * Creates the buffer to store the stroke-dasharray, assuming out-of-memory
+     * does not occur. The buffer's address is assigned to mDashPattern and
+     * returned to the caller as a non-const pointer (so that the caller can
+     * initialize the values in the buffer, since mDashPattern is const).
+     */
+    Float* InitDashPattern(size_t aDashCount) {
+      if (aDashCount <= MOZ_ARRAY_LENGTH(mSmallArray)) {
+        mDashPattern = mSmallArray;
+        return mSmallArray;
+      }
+      Float* nonConstArray = new (mozilla::fallible) Float[aDashCount];
+      mDashPattern = nonConstArray;
+      return nonConstArray;
+    }
+    void DiscardDashPattern() {
+      if (mDashPattern && mDashPattern != mSmallArray) {
+        delete[] mDashPattern;
+      }
+      mDashLength = 0;
+      mDashPattern = nullptr;
+    }
+
+   private:
+    // Most dasharrays will fit in this and save us allocating
+    Float mSmallArray[16];
+  };
+
+  enum StrokeOptionFlags { eAllStrokeOptions, eIgnoreStrokeDashing };
+  /**
+   * Note: the linecap style returned in aStrokeOptions is not valid when
+   * ShapeTypeHasNoCorners(aElement) == true && aFlags == eIgnoreStrokeDashing,
+   * since when aElement has no corners the rendered linecap style depends on
+   * whether or not the stroke is dashed.
+   */
+  static void GetStrokeOptions(AutoStrokeOptions* aStrokeOptions,
+                               dom::SVGElement* aElement,
+                               const ComputedStyle* aComputedStyle,
+                               const SVGContextPaint* aContextPaint,
+                               StrokeOptionFlags aFlags = eAllStrokeOptions);
+
+  /**
+   * Returns the current computed value of the CSS property 'stroke-width' for
+   * the given element. aComputedStyle may be provided as an optimization.
+   * aContextPaint is also optional.
+   *
+   * Note that this function does NOT take account of the value of the 'stroke'
+   * and 'stroke-opacity' properties to, say, return zero if they are "none" or
+   * "0", respectively.
+   */
+  static Float GetStrokeWidth(const dom::SVGElement* aElement,
+                              const ComputedStyle* aComputedStyle,
+                              const SVGContextPaint* aContextPaint);
+
+  /*
+   * Get the number of CSS px (user units) per em (i.e. the em-height in user
+   * units) for an nsIContent
+   *
+   * XXX document the conditions under which these may fail, and what they
+   * return in those cases.
+   */
+  static float GetFontSize(const mozilla::dom::Element* aElement);
+  static float GetFontSize(const nsIFrame* aFrame);
+  static float GetFontSize(const ComputedStyle*, nsPresContext*);
+  /*
+   * Get the number of CSS px (user units) per ex (i.e. the x-height in user
+   * units) for an nsIContent
+   *
+   * XXX document the conditions under which these may fail, and what they
+   * return in those cases.
+   */
+  static float GetFontXHeight(const mozilla::dom::Element* aElement);
+  static float GetFontXHeight(const nsIFrame* aFrame);
+  static float GetFontXHeight(const ComputedStyle*, nsPresContext*);
+
+  /*
+   * Report a localized error message to the error console.
+   */
+  static nsresult ReportToConsole(const dom::Document* doc,
+                                  const char* aWarning,
+                                  const nsTArray<nsString>& aParams);
+
+  static Matrix GetCTM(dom::SVGElement* aElement, bool aScreenCTM);
+
+  /**
+   * Gets the tight bounds-space stroke bounds of the non-scaling-stroked rect
+   * aRect.
+   * @param aToBoundsSpace transforms from source space to the space aBounds
+   *        should be computed in.  Must be rectilinear.
+   * @param aToNonScalingStrokeSpace transforms from source
+   *        space to the space in which non-scaling stroke should be applied.
+   *        Must be rectilinear.
+   */
+  static void RectilinearGetStrokeBounds(const Rect& aRect,
+                                         const Matrix& aToBoundsSpace,
+                                         const Matrix& aToNonScalingStrokeSpace,
+                                         float aStrokeWidth, Rect* aBounds);
+
+  /**
+   * Check if this is one of the SVG elements that SVG 1.1 Full says
+   * establishes a viewport: svg, symbol, image or foreignObject.
+   */
+  static bool EstablishesViewport(const nsIContent* aContent);
+
+  static mozilla::dom::SVGViewportElement* GetNearestViewportElement(
+      const nsIContent* aContent);
+
+  /* enum for specifying coordinate direction for ObjectSpace/UserSpace */
+  enum ctxDirection { X, Y, XY };
+
+  /**
+   * Computes sqrt((aWidth^2 + aHeight^2)/2);
+   */
+  static double ComputeNormalizedHypotenuse(double aWidth, double aHeight);
+
+  /* Returns the angle halfway between the two specified angles */
+  static float AngleBisect(float a1, float a2);
+
+  /* Generate a viewbox to viewport transformation matrix */
+
+  static Matrix GetViewBoxTransform(
+      float aViewportWidth, float aViewportHeight, float aViewboxX,
+      float aViewboxY, float aViewboxWidth, float aViewboxHeight,
+      const SVGAnimatedPreserveAspectRatio& aPreserveAspectRatio);
+
+  static Matrix GetViewBoxTransform(
+      float aViewportWidth, float aViewportHeight, float aViewboxX,
+      float aViewboxY, float aViewboxWidth, float aViewboxHeight,
+      const SVGPreserveAspectRatio& aPreserveAspectRatio);
+
+  static mozilla::RangedPtr<const char16_t> GetStartRangedPtr(
+      const nsAString& aString);
+
+  static mozilla::RangedPtr<const char16_t> GetEndRangedPtr(
+      const nsAString& aString);
+
+  /**
+   * Parses the sign (+ or -) of a number and moves aIter to the next
+   * character if a sign is found.
+   * @param aSignMultiplier [outparam] -1 if the sign is negative otherwise 1
+   * @return false if we hit the end of the string (i.e. if aIter is initially
+   *         at aEnd, or if we reach aEnd right after the sign character).
+   */
+  static inline bool ParseOptionalSign(
+      mozilla::RangedPtr<const char16_t>& aIter,
+      const mozilla::RangedPtr<const char16_t>& aEnd,
+      int32_t& aSignMultiplier) {
+    if (aIter == aEnd) {
+      return false;
+    }
+    aSignMultiplier = *aIter == '-' ? -1 : 1;
+
+    mozilla::RangedPtr<const char16_t> iter(aIter);
+
+    if (*iter == '-' || *iter == '+') {
+      ++iter;
+      if (iter == aEnd) {
+        return false;
+      }
+    }
+    aIter = iter;
+    return true;
+  }
+
+  /**
+   * Parse a number of the form:
+   * number ::= integer ([Ee] integer)? | [+-]? [0-9]* "." [0-9]+ ([Ee]
+   * integer)? Parsing fails if the number cannot be represented by a floatType.
+   * If parsing succeeds, aIter is updated so that it points to the character
+   * after the end of the number, otherwise it is left unchanged
+   */
+  template <class floatType>
+  static bool ParseNumber(mozilla::RangedPtr<const char16_t>& aIter,
+                          const mozilla::RangedPtr<const char16_t>& aEnd,
+                          floatType& aValue);
+
+  /**
+   * Parse a number of the form:
+   * number ::= integer ([Ee] integer)? | [+-]? [0-9]* "." [0-9]+ ([Ee]
+   * integer)? Parsing fails if there is anything left over after the number, or
+   * the number cannot be represented by a floatType.
+   */
+  template <class floatType>
+  static bool ParseNumber(const nsAString& aString, floatType& aValue);
+
+  /**
+   * Parse an integer of the form:
+   * integer ::= [+-]? [0-9]+
+   * The returned number is clamped to an int32_t if outside that range.
+   * If parsing succeeds, aIter is updated so that it points to the character
+   * after the end of the number, otherwise it is left unchanged
+   */
+  static bool ParseInteger(mozilla::RangedPtr<const char16_t>& aIter,
+                           const mozilla::RangedPtr<const char16_t>& aEnd,
+                           int32_t& aValue);
+
+  /**
+   * Parse an integer of the form:
+   * integer ::= [+-]? [0-9]+
+   * The returned number is clamped to an int32_t if outside that range.
+   * Parsing fails if there is anything left over after the number.
+   */
+  static bool ParseInteger(const nsAString& aString, int32_t& aValue);
+
+  // XXX This should rather use LengthPercentage instead of
+  // StyleLengthPercentageUnion, but that's a type alias defined in
+  // ServoStyleConsts.h, and we don't want to avoid including that large header
+  // with all its dependencies. If a forwarding header were generated by
+  // cbindgen, we could include that.
+  // https://github.com/eqrion/cbindgen/issues/617 addresses this.
+  /**
+   * Converts a LengthPercentage into a userspace value, resolving percentage
+   * values relative to aContent's SVG viewport.
+   */
+  static float CoordToFloat(const dom::SVGElement* aContent,
+                            const StyleLengthPercentageUnion&,
+                            uint8_t aCtxType = SVGContentUtils::XY);
+  /**
+   * Parse the SVG path string
+   * Returns a path
+   * string formatted as an SVG path
+   */
+  static already_AddRefed<mozilla::gfx::Path> GetPath(
+      const nsAString& aPathString);
+
+  /**
+   *  Returns true if aContent is one of the elements whose stroke is guaranteed
+   *  to have no corners: circle or ellipse
+   */
+  static bool ShapeTypeHasNoCorners(const nsIContent* aContent);
+
+  /**
+   *  Return one token in aString, aString may have leading and trailing
+   * whitespace; aSuccess will be set to false if there is no token or more than
+   * one token, otherwise it's set to true.
+   */
+  static nsDependentSubstring GetAndEnsureOneToken(const nsAString& aString,
+                                                   bool& aSuccess);
+};
+
+}  // namespace mozilla
+
+#endif  // DOM_SVG_SVGCONTENTUTILS_H_