The Tor Browser: gfx/2d/BaseRect.h@97036ab72558 (annotated)

gfx/2d/BaseRect.h@97036ab72558 (annotated)

gfx/2d/BaseRect.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * 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 MOZILLA_GFX_BASERECT_H_
 #define MOZILLA_GFX_BASERECT_H_
 #include <algorithm>
 #include <cmath>
 #include "mozilla/Assertions.h"
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/TypeTraits.h"
 namespace mozilla {
 namespace gfx {
 /**
  * Rectangles have two interpretations: a set of (zero-size) points,
  * and a rectangular area of the plane. Most rectangle operations behave
  * the same no matter what interpretation is being used, but some operations
  * differ:
  * -- Equality tests behave differently. When a rectangle represents an area,
  * all zero-width and zero-height rectangles are equal to each other since they
  * represent the empty area. But when a rectangle represents a set of
  * mathematical points, zero-width and zero-height rectangles can be unequal.
  * -- The union operation can behave differently. When rectangles represent
  * areas, taking the union of a zero-width or zero-height rectangle with
  * another rectangle can just ignore the empty rectangle. But when rectangles
  * represent sets of mathematical points, we may need to extend the latter
  * rectangle to include the points of a zero-width or zero-height rectangle.
  *
  * To ensure that these interpretations are explicitly disambiguated, we
  * deny access to the == and != operators and require use of IsEqualEdges and
  * IsEqualInterior instead. Similarly we provide separate Union and UnionEdges
  * methods.
  *
  * Do not use this class directly. Subclass it, pass that subclass as the
  * Sub parameter, and only use that subclass.
  */
 template <class T, class Sub, class Point, class SizeT, class MarginT>
 struct BaseRect {
   T x, y, width, height;
   // Constructors
   BaseRect() : x(0), y(0), width(0), height(0) {}
   BaseRect(const Point& aOrigin, const SizeT &aSize) :
       x(aOrigin.x), y(aOrigin.y), width(aSize.width), height(aSize.height)
   {
   }
   BaseRect(T aX, T aY, T aWidth, T aHeight) :
       x(aX), y(aY), width(aWidth), height(aHeight)
   {
   }
   // Emptiness. An empty rect is one that has no area, i.e. its height or width
   // is <= 0
   bool IsEmpty() const { return height <= 0 || width <= 0; }
   void SetEmpty() { width = height = 0; }
   // "Finite" means not inf and not NaN
   bool IsFinite() const
   {
     typedef typename mozilla::Conditional<mozilla::IsSame<T, float>::value, float, double>::Type FloatType;
     return (mozilla::IsFinite(FloatType(x)) &&
             mozilla::IsFinite(FloatType(y)) &&
             mozilla::IsFinite(FloatType(width)) &&
             mozilla::IsFinite(FloatType(height)));
   }
   // Returns true if this rectangle contains the interior of aRect. Always
   // returns true if aRect is empty, and always returns false is aRect is
   // nonempty but this rect is empty.
   bool Contains(const Sub& aRect) const
   {
     return aRect.IsEmpty() ||
            (x <= aRect.x && aRect.XMost() <= XMost() &&
             y <= aRect.y && aRect.YMost() <= YMost());
   }
   // Returns true if this rectangle contains the rectangle (aX,aY,1,1).
   bool Contains(T aX, T aY) const
   {
     return x <= aX && aX + 1 <= XMost() &&
            y <= aY && aY + 1 <= YMost();
   }
   // Returns true if this rectangle contains the rectangle (aPoint.x,aPoint.y,1,1).
   bool Contains(const Point& aPoint) const { return Contains(aPoint.x, aPoint.y); }
   // Intersection. Returns TRUE if the receiver's area has non-empty
   // intersection with aRect's area, and FALSE otherwise.
   // Always returns false if aRect is empty or 'this' is empty.
   bool Intersects(const Sub& aRect) const
   {
     return x < aRect.XMost() && aRect.x < XMost() &&
            y < aRect.YMost() && aRect.y < YMost();
   }
   // Returns the rectangle containing the intersection of the points
   // (including edges) of *this and aRect. If there are no points in that
   // intersection, returns an empty rectangle with x/y set to the std::max of the x/y
   // of *this and aRect.
   Sub Intersect(const Sub& aRect) const
   {
     Sub result;
     result.x = std::max<T>(x, aRect.x);
     result.y = std::max<T>(y, aRect.y);
     result.width = std::min<T>(XMost(), aRect.XMost()) - result.x;
     result.height = std::min<T>(YMost(), aRect.YMost()) - result.y;
     if (result.width < 0 || result.height < 0) {
       result.SizeTo(0, 0);
     }
     return result;
   }
   // Sets *this to be the rectangle containing the intersection of the points
   // (including edges) of *this and aRect. If there are no points in that
   // intersection, sets *this to be an empty rectangle with x/y set to the std::max
   // of the x/y of *this and aRect.
   //
   // 'this' can be the same object as either aRect1 or aRect2
   bool IntersectRect(const Sub& aRect1, const Sub& aRect2)
   {
     *static_cast<Sub*>(this) = aRect1.Intersect(aRect2);
     return !IsEmpty();
   }
   // Returns the smallest rectangle that contains both the area of both
   // this and aRect2.
   // Thus, empty input rectangles are ignored.
   // If both rectangles are empty, returns this.
   Sub Union(const Sub& aRect) const
   {
     if (IsEmpty()) {
       return aRect;
     } else if (aRect.IsEmpty()) {
       return *static_cast<const Sub*>(this);
     } else {
       return UnionEdges(aRect);
     }
   }
   // Returns the smallest rectangle that contains both the points (including
   // edges) of both aRect1 and aRect2.
   // Thus, empty input rectangles are allowed to affect the result.
   Sub UnionEdges(const Sub& aRect) const
   {
     Sub result;
     result.x = std::min(x, aRect.x);
     result.y = std::min(y, aRect.y);
     result.width = std::max(XMost(), aRect.XMost()) - result.x;
     result.height = std::max(YMost(), aRect.YMost()) - result.y;
     return result;
   }
   // Computes the smallest rectangle that contains both the area of both
   // aRect1 and aRect2, and fills 'this' with the result.
   // Thus, empty input rectangles are ignored.
   // If both rectangles are empty, sets 'this' to aRect2.
   //
   // 'this' can be the same object as either aRect1 or aRect2
   void UnionRect(const Sub& aRect1, const Sub& aRect2)
   {
     *static_cast<Sub*>(this) = aRect1.Union(aRect2);
   }
   // Computes the smallest rectangle that contains both the points (including
   // edges) of both aRect1 and aRect2.
   // Thus, empty input rectangles are allowed to affect the result.
   //
   // 'this' can be the same object as either aRect1 or aRect2
   void UnionRectEdges(const Sub& aRect1, const Sub& aRect2)
   {
     *static_cast<Sub*>(this) = aRect1.UnionEdges(aRect2);
   }
   void SetRect(T aX, T aY, T aWidth, T aHeight)
   {
     x = aX; y = aY; width = aWidth; height = aHeight;
   }
   void SetRect(const Point& aPt, const SizeT& aSize)
   {
     SetRect(aPt.x, aPt.y, aSize.width, aSize.height);
   }
   void MoveTo(T aX, T aY) { x = aX; y = aY; }
   void MoveTo(const Point& aPoint) { x = aPoint.x; y = aPoint.y; }
   void MoveBy(T aDx, T aDy) { x += aDx; y += aDy; }
   void MoveBy(const Point& aPoint) { x += aPoint.x; y += aPoint.y; }
   void SizeTo(T aWidth, T aHeight) { width = aWidth; height = aHeight; }
   void SizeTo(const SizeT& aSize) { width = aSize.width; height = aSize.height; }
   void Inflate(T aD) { Inflate(aD, aD); }
   void Inflate(T aDx, T aDy)
   {
     x -= aDx;
     y -= aDy;
     width += 2 * aDx;
     height += 2 * aDy;
   }
   void Inflate(const MarginT& aMargin)
   {
     x -= aMargin.left;
     y -= aMargin.top;
     width += aMargin.LeftRight();
     height += aMargin.TopBottom();
   }
   void Inflate(const SizeT& aSize) { Inflate(aSize.width, aSize.height); }
   void Deflate(T aD) { Deflate(aD, aD); }
   void Deflate(T aDx, T aDy)
   {
     x += aDx;
     y += aDy;
     width = std::max(T(0), width - 2 * aDx);
     height = std::max(T(0), height - 2 * aDy);
   }
   void Deflate(const MarginT& aMargin)
   {
     x += aMargin.left;
     y += aMargin.top;
     width = std::max(T(0), width - aMargin.LeftRight());
     height = std::max(T(0), height - aMargin.TopBottom());
   }
   void Deflate(const SizeT& aSize) { Deflate(aSize.width, aSize.height); }
   // Return true if the rectangles contain the same set of points, including
   // points on the edges.
   // Use when we care about the exact x/y/width/height values being
   // equal (i.e. we care about differences in empty rectangles).
   bool IsEqualEdges(const Sub& aRect) const
   {
     return x == aRect.x && y == aRect.y &&
            width == aRect.width && height == aRect.height;
   }
   // Return true if the rectangles contain the same area of the plane.
   // Use when we do not care about differences in empty rectangles.
   bool IsEqualInterior(const Sub& aRect) const
   {
     return IsEqualEdges(aRect) || (IsEmpty() && aRect.IsEmpty());
   }
   Sub operator+(const Point& aPoint) const
   {
     return Sub(x + aPoint.x, y + aPoint.y, width, height);
   }
   Sub operator-(const Point& aPoint) const
   {
     return Sub(x - aPoint.x, y - aPoint.y, width, height);
   }
   Sub& operator+=(const Point& aPoint)
   {
     MoveBy(aPoint);
     return *static_cast<Sub*>(this);
   }
   Sub& operator-=(const Point& aPoint)
   {
     MoveBy(-aPoint);
     return *static_cast<Sub*>(this);
   }
   // Find difference as a Margin
   MarginT operator-(const Sub& aRect) const
   {
     return MarginT(aRect.y - y,
                    XMost() - aRect.XMost(),
                    YMost() - aRect.YMost(),
                    aRect.x - x);
   }
   // Helpers for accessing the vertices
   Point TopLeft() const { return Point(x, y); }
   Point TopRight() const { return Point(XMost(), y); }
   Point BottomLeft() const { return Point(x, YMost()); }
   Point BottomRight() const { return Point(XMost(), YMost()); }
   Point Center() const { return Point(x, y) + Point(width, height)/2; }
   SizeT Size() const { return SizeT(width, height); }
   // Helper methods for computing the extents
   T X() const { return x; }
   T Y() const { return y; }
   T Width() const { return width; }
   T Height() const { return height; }
   T XMost() const { return x + width; }
   T YMost() const { return y + height; }
   // Moves one edge of the rect without moving the opposite edge.
   void SetLeftEdge(T aX) {
     MOZ_ASSERT(aX <= XMost());
     width = XMost() - aX;
     x = aX;
   }
   void SetRightEdge(T aXMost) {
     MOZ_ASSERT(aXMost >= x);
     width = aXMost - x;
   }
   void SetTopEdge(T aY) {
     MOZ_ASSERT(aY <= YMost());
     height = YMost() - aY;
     y = aY;
   }
   void SetBottomEdge(T aYMost) {
     MOZ_ASSERT(aYMost >= y);
     height = aYMost - y;
   }
   // Round the rectangle edges to integer coordinates, such that the rounded
   // rectangle has the same set of pixel centers as the original rectangle.
   // Edges at offset 0.5 round up.
   // Suitable for most places where integral device coordinates
   // are needed, but note that any translation should be applied first to
   // avoid pixel rounding errors.
   // Note that this is *not* rounding to nearest integer if the values are negative.
   // They are always rounding as floor(n + 0.5).
   // See https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
   // If you need similar method which is using NS_round(), you should create
   // new |RoundAwayFromZero()| method.
   void Round()
   {
     T x0 = static_cast<T>(floor(T(X()) + 0.5));
     T y0 = static_cast<T>(floor(T(Y()) + 0.5));
     T x1 = static_cast<T>(floor(T(XMost()) + 0.5));
     T y1 = static_cast<T>(floor(T(YMost()) + 0.5));
     x = x0;
     y = y0;
     width = x1 - x0;
     height = y1 - y0;
   }
   // Snap the rectangle edges to integer coordinates, such that the
   // original rectangle contains the resulting rectangle.
   void RoundIn()
   {
     T x0 = static_cast<T>(ceil(T(X())));
     T y0 = static_cast<T>(ceil(T(Y())));
     T x1 = static_cast<T>(floor(T(XMost())));
     T y1 = static_cast<T>(floor(T(YMost())));
     x = x0;
     y = y0;
     width = x1 - x0;
     height = y1 - y0;
   }
   // Snap the rectangle edges to integer coordinates, such that the
   // resulting rectangle contains the original rectangle.
   void RoundOut()
   {
     T x0 = static_cast<T>(floor(T(X())));
     T y0 = static_cast<T>(floor(T(Y())));
     T x1 = static_cast<T>(ceil(T(XMost())));
     T y1 = static_cast<T>(ceil(T(YMost())));
     x = x0;
     y = y0;
     width = x1 - x0;
     height = y1 - y0;
   }
   // Scale 'this' by aScale without doing any rounding.
   void Scale(T aScale) { Scale(aScale, aScale); }
   // Scale 'this' by aXScale and aYScale, without doing any rounding.
   void Scale(T aXScale, T aYScale)
   {
     T right = XMost() * aXScale;
     T bottom = YMost() * aYScale;
     x = x * aXScale;
     y = y * aYScale;
     width = right - x;
     height = bottom - y;
   }
   // Scale 'this' by aScale, converting coordinates to integers so that the result is
   // the smallest integer-coordinate rectangle containing the unrounded result.
   // Note: this can turn an empty rectangle into a non-empty rectangle
   void ScaleRoundOut(double aScale) { ScaleRoundOut(aScale, aScale); }
   // Scale 'this' by aXScale and aYScale, converting coordinates to integers so
   // that the result is the smallest integer-coordinate rectangle containing the
   // unrounded result.
   // Note: this can turn an empty rectangle into a non-empty rectangle
   void ScaleRoundOut(double aXScale, double aYScale)
   {
     T right = static_cast<T>(ceil(double(XMost()) * aXScale));
     T bottom = static_cast<T>(ceil(double(YMost()) * aYScale));
     x = static_cast<T>(floor(double(x) * aXScale));
     y = static_cast<T>(floor(double(y) * aYScale));
     width = right - x;
     height = bottom - y;
   }
   // Scale 'this' by aScale, converting coordinates to integers so that the result is
   // the largest integer-coordinate rectangle contained by the unrounded result.
   void ScaleRoundIn(double aScale) { ScaleRoundIn(aScale, aScale); }
   // Scale 'this' by aXScale and aYScale, converting coordinates to integers so
   // that the result is the largest integer-coordinate rectangle contained by the
   // unrounded result.
   void ScaleRoundIn(double aXScale, double aYScale)
   {
     T right = static_cast<T>(floor(double(XMost()) * aXScale));
     T bottom = static_cast<T>(floor(double(YMost()) * aYScale));
     x = static_cast<T>(ceil(double(x) * aXScale));
     y = static_cast<T>(ceil(double(y) * aYScale));
     width = std::max<T>(0, right - x);
     height = std::max<T>(0, bottom - y);
   }
   // Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
   // the smallest integer-coordinate rectangle containing the unrounded result.
   // Note: this can turn an empty rectangle into a non-empty rectangle
   void ScaleInverseRoundOut(double aScale) { ScaleInverseRoundOut(aScale, aScale); }
   // Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
   // that the result is the smallest integer-coordinate rectangle containing the
   // unrounded result.
   // Note: this can turn an empty rectangle into a non-empty rectangle
   void ScaleInverseRoundOut(double aXScale, double aYScale)
   {
     T right = static_cast<T>(ceil(double(XMost()) / aXScale));
     T bottom = static_cast<T>(ceil(double(YMost()) / aYScale));
     x = static_cast<T>(floor(double(x) / aXScale));
     y = static_cast<T>(floor(double(y) / aYScale));
     width = right - x;
     height = bottom - y;
   }
   // Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
   // the largest integer-coordinate rectangle contained by the unrounded result.
   void ScaleInverseRoundIn(double aScale) { ScaleInverseRoundIn(aScale, aScale); }
   // Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
   // that the result is the largest integer-coordinate rectangle contained by the
   // unrounded result.
   void ScaleInverseRoundIn(double aXScale, double aYScale)
   {
     T right = static_cast<T>(floor(double(XMost()) / aXScale));
     T bottom = static_cast<T>(floor(double(YMost()) / aYScale));
     x = static_cast<T>(ceil(double(x) / aXScale));
     y = static_cast<T>(ceil(double(y) / aYScale));
     width = std::max<T>(0, right - x);
     height = std::max<T>(0, bottom - y);
   }
   /**
    * Clamp aPoint to this rectangle. It is allowed to end up on any
    * edge of the rectangle.
    */
   Point ClampPoint(const Point& aPoint) const
   {
     return Point(std::max(x, std::min(XMost(), aPoint.x)),
                  std::max(y, std::min(YMost(), aPoint.y)));
   }
   /**
    * Clamp this rectangle to be inside aRect. The function returns a copy of
    * this rect after it is forced inside the bounds of aRect. It will attempt to
    * retain the size but will shrink the dimensions that don't fit.
    */
   Sub ForceInside(const Sub& aRect) const
   {
     Sub rect(std::max(aRect.x, x),
              std::max(aRect.y, y),
              std::min(aRect.width, width),
              std::min(aRect.height, height));
     rect.x = std::min(rect.XMost(), aRect.XMost()) - rect.width;
     rect.y = std::min(rect.YMost(), aRect.YMost()) - rect.height;
     return rect;
   }
 private:
   // Do not use the default operator== or operator!= !
   // Use IsEqualEdges or IsEqualInterior explicitly.
   bool operator==(const Sub& aRect) const { return false; }
   bool operator!=(const Sub& aRect) const { return false; }
 };
 }
 }
 #endif /* MOZILLA_GFX_BASERECT_H_ */

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gfx/2d/BaseRect.h@97036ab72558 (annotated)

gfx/2d/BaseRect.h