Revert "make SkClipStack.h private (in src)"

This reverts commit 3efca0a2a8fc412a318199fa386c1375b55ee81e.

Reason for revert: update caller in GraphicsContext.cpp

Original change's description:
> make SkClipStack.h private (in src)
> 
> BUG=skia:
> 
> Change-Id: I05f1140fe483f4a92093cb9783c6e9f067420d30
> Reviewed-on: https://skia-review.googlesource.com/8481
> Reviewed-by: Florin Malita <fmalita@chromium.org>
> Commit-Queue: Mike Reed <reed@google.com>
> 

TBR=fmalita@chromium.org,reed@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Change-Id: Iff1138d72ff2d1187d522487fe76ea293f706f60
Reviewed-on: https://skia-review.googlesource.com/8501
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 554 insertions, 0 deletions

diff --git a/include/core/SkClipStack.h b/include/core/SkClipStack.h
new file mode 100644
index 0000000000..2f24d69502
--- /dev/null
+++ b/include/core/SkClipStack.h
@@ -0,0 +1,554 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkClipStack_DEFINED
+#define SkClipStack_DEFINED
+
+#include "../private/SkMessageBus.h"
+#include "SkCanvas.h"
+#include "SkDeque.h"
+#include "SkPath.h"
+#include "SkRRect.h"
+#include "SkRect.h"
+#include "SkRegion.h"
+#include "SkTLazy.h"
+
+#if SK_SUPPORT_GPU
+#include "GrResourceKey.h"
+#endif
+
+class SkCanvasClipVisitor;
+
+// Because a single save/restore state can have multiple clips, this class
+// stores the stack depth (fSaveCount) and clips (fDeque) separately.
+// Each clip in fDeque stores the stack state to which it belongs
+// (i.e., the fSaveCount in force when it was added). Restores are thus
+// implemented by removing clips from fDeque that have an fSaveCount larger
+// then the freshly decremented count.
+class SK_API SkClipStack : public SkNVRefCnt<SkClipStack> {
+public:
+    enum BoundsType {
+        // The bounding box contains all the pixels that can be written to
+        kNormal_BoundsType,
+        // The bounding box contains all the pixels that cannot be written to.
+        // The real bound extends out to infinity and all the pixels outside
+        // of the bound can be written to. Note that some of the pixels inside
+        // the bound may also be writeable but all pixels that cannot be
+        // written to are guaranteed to be inside.
+        kInsideOut_BoundsType
+    };
+
+    class Element {
+    public:
+        enum Type {
+            //!< This element makes the clip empty (regardless of previous elements).
+            kEmpty_Type,
+            //!< This element combines a rect with the current clip using a set operation
+            kRect_Type,
+            //!< This element combines a round-rect with the current clip using a set operation
+            kRRect_Type,
+            //!< This element combines a path with the current clip using a set operation
+            kPath_Type,
+
+            kLastType = kPath_Type
+        };
+        static const int kTypeCnt = kLastType + 1;
+
+        Element() {
+            this->initCommon(0, SkClipOp::kReplace_deprecated, false);
+            this->setEmpty();
+        }
+
+        Element(const Element&);
+
+        Element(const SkRect& rect, SkClipOp op, bool doAA) {
+            this->initRect(0, rect, op, doAA);
+        }
+
+        Element(const SkRRect& rrect, SkClipOp op, bool doAA) {
+            this->initRRect(0, rrect, op, doAA);
+        }
+
+        Element(const SkPath& path, SkClipOp op, bool doAA) {
+            this->initPath(0, path, op, doAA);
+        }
+
+        ~Element() {
+#if SK_SUPPORT_GPU
+            for (int i = 0; i < fMessages.count(); ++i) {
+                SkMessageBus<GrUniqueKeyInvalidatedMessage>::Post(*fMessages[i]);
+            }
+#endif
+        }
+
+        bool operator== (const Element& element) const;
+        bool operator!= (const Element& element) const { return !(*this == element); }
+
+        //!< Call to get the type of the clip element.
+        Type getType() const { return fType; }
+
+        //!< Call to get the save count associated with this clip element.
+        int getSaveCount() const { return fSaveCount; }
+
+        //!< Call if getType() is kPath to get the path.
+        const SkPath& getPath() const { SkASSERT(kPath_Type == fType); return *fPath.get(); }
+
+        //!< Call if getType() is kRRect to get the round-rect.
+        const SkRRect& getRRect() const { SkASSERT(kRRect_Type == fType); return fRRect; }
+
+        //!< Call if getType() is kRect to get the rect.
+        const SkRect& getRect() const {
+            SkASSERT(kRect_Type == fType && (fRRect.isRect() || fRRect.isEmpty()));
+            return fRRect.getBounds();
+        }
+
+        //!< Call if getType() is not kEmpty to get the set operation used to combine this element.
+        SkClipOp getOp() const { return fOp; }
+
+        //!< Call to get the element as a path, regardless of its type.
+        void asPath(SkPath* path) const;
+
+        //!< Call if getType() is not kPath to get the element as a round rect.
+        const SkRRect& asRRect() const { SkASSERT(kPath_Type != fType); return fRRect; }
+
+        /** If getType() is not kEmpty this indicates whether the clip shape should be anti-aliased
+            when it is rasterized. */
+        bool isAA() const { return fDoAA; }
+
+        //!< Inverts the fill of the clip shape. Note that a kEmpty element remains kEmpty.
+        void invertShapeFillType();
+
+        //!< Sets the set operation represented by the element.
+        void setOp(SkClipOp op) { fOp = op; }
+
+        /** The GenID can be used by clip stack clients to cache representations of the clip. The
+            ID corresponds to the set of clip elements up to and including this element within the
+            stack not to the element itself. That is the same clip path in different stacks will
+            have a different ID since the elements produce different clip result in the context of
+            their stacks. */
+        int32_t getGenID() const { SkASSERT(kInvalidGenID != fGenID); return fGenID; }
+
+        /**
+         * Gets the bounds of the clip element, either the rect or path bounds. (Whether the shape
+         * is inverse filled is not considered.)
+         */
+        const SkRect& getBounds() const {
+            static const SkRect kEmpty = { 0, 0, 0, 0 };
+            switch (fType) {
+                case kRect_Type:  // fallthrough
+                case kRRect_Type:
+                    return fRRect.getBounds();
+                case kPath_Type:
+                    return fPath.get()->getBounds();
+                case kEmpty_Type:
+                    return kEmpty;
+                default:
+                    SkDEBUGFAIL("Unexpected type.");
+                    return kEmpty;
+            }
+        }
+
+        /**
+         * Conservatively checks whether the clip shape contains the rect param. (Whether the shape
+         * is inverse filled is not considered.)
+         */
+        bool contains(const SkRect& rect) const {
+            switch (fType) {
+                case kRect_Type:
+                    return this->getRect().contains(rect);
+                case kRRect_Type:
+                    return fRRect.contains(rect);
+                case kPath_Type:
+                    return fPath.get()->conservativelyContainsRect(rect);
+                case kEmpty_Type:
+                    return false;
+                default:
+                    SkDEBUGFAIL("Unexpected type.");
+                    return false;
+            }
+        }
+
+        bool contains(const SkRRect& rrect) const {
+            switch (fType) {
+                case kRect_Type:
+                    return this->getRect().contains(rrect.getBounds());
+                case kRRect_Type:
+                    // We don't currently have a generalized rrect-rrect containment.
+                    return fRRect.contains(rrect.getBounds()) || rrect == fRRect;
+                case kPath_Type:
+                    return fPath.get()->conservativelyContainsRect(rrect.getBounds());
+                case kEmpty_Type:
+                    return false;
+                default:
+                    SkDEBUGFAIL("Unexpected type.");
+                    return false;
+            }
+        }
+
+        /**
+         * Is the clip shape inverse filled.
+         */
+        bool isInverseFilled() const {
+            return kPath_Type == fType && fPath.get()->isInverseFillType();
+        }
+
+        /**
+        * Replay this clip into the visitor.
+        */
+        void replay(SkCanvasClipVisitor*) const;
+
+#ifdef SK_DEBUG
+        /**
+         * Dumps the element to SkDebugf. This is intended for Skia development debugging
+         * Don't rely on the existence of this function or the formatting of its output.
+         */
+        void dump() const;
+#endif
+
+#if SK_SUPPORT_GPU
+        /**
+         * This is used to purge any GPU resource cache items that become unreachable when
+         * the element is destroyed because their key is based on this element's gen ID.
+         */
+        void addResourceInvalidationMessage(
+                std::unique_ptr<GrUniqueKeyInvalidatedMessage> msg) const {
+            fMessages.emplace_back(std::move(msg));
+        }
+#endif
+
+    private:
+        friend class SkClipStack;
+
+        SkTLazy<SkPath> fPath;
+        SkRRect fRRect;
+        int fSaveCount;  // save count of stack when this element was added.
+        SkClipOp fOp;
+        Type fType;
+        bool fDoAA;
+
+        /* fFiniteBoundType and fFiniteBound are used to incrementally update the clip stack's
+           bound. When fFiniteBoundType is kNormal_BoundsType, fFiniteBound represents the
+           conservative bounding box of the pixels that aren't clipped (i.e., any pixels that can be
+           drawn to are inside the bound). When fFiniteBoundType is kInsideOut_BoundsType (which
+           occurs when a clip is inverse filled), fFiniteBound represents the conservative bounding
+           box of the pixels that _are_ clipped (i.e., any pixels that cannot be drawn to are inside
+           the bound). When fFiniteBoundType is kInsideOut_BoundsType the actual bound is the
+           infinite plane. This behavior of fFiniteBoundType and fFiniteBound is required so that we
+           can capture the cancelling out of the extensions to infinity when two inverse filled
+           clips are Booleaned together. */
+        SkClipStack::BoundsType fFiniteBoundType;
+        SkRect fFiniteBound;
+
+        // When element is applied to the previous elements in the stack is the result known to be
+        // equivalent to a single rect intersection? IIOW, is the clip effectively a rectangle.
+        bool fIsIntersectionOfRects;
+
+        int fGenID;
+#if SK_SUPPORT_GPU
+        mutable SkTArray<std::unique_ptr<GrUniqueKeyInvalidatedMessage>> fMessages;
+#endif
+        Element(int saveCount) {
+            this->initCommon(saveCount, SkClipOp::kReplace_deprecated, false);
+            this->setEmpty();
+        }
+
+        Element(int saveCount, const SkRRect& rrect, SkClipOp op, bool doAA) {
+            this->initRRect(saveCount, rrect, op, doAA);
+        }
+
+        Element(int saveCount, const SkRect& rect, SkClipOp op, bool doAA) {
+            this->initRect(saveCount, rect, op, doAA);
+        }
+
+        Element(int saveCount, const SkPath& path, SkClipOp op, bool doAA) {
+            this->initPath(saveCount, path, op, doAA);
+        }
+
+        void initCommon(int saveCount, SkClipOp op, bool doAA) {
+            fSaveCount = saveCount;
+            fOp = op;
+            fDoAA = doAA;
+            // A default of inside-out and empty bounds means the bounds are effectively void as it
+            // indicates that nothing is known to be outside the clip.
+            fFiniteBoundType = kInsideOut_BoundsType;
+            fFiniteBound.setEmpty();
+            fIsIntersectionOfRects = false;
+            fGenID = kInvalidGenID;
+        }
+
+        void initRect(int saveCount, const SkRect& rect, SkClipOp op, bool doAA) {
+            fRRect.setRect(rect);
+            fType = kRect_Type;
+            this->initCommon(saveCount, op, doAA);
+        }
+
+        void initRRect(int saveCount, const SkRRect& rrect, SkClipOp op, bool doAA) {
+            SkRRect::Type type = rrect.getType();
+            fRRect = rrect;
+            if (SkRRect::kRect_Type == type || SkRRect::kEmpty_Type == type) {
+                fType = kRect_Type;
+            } else {
+                fType = kRRect_Type;
+            }
+            this->initCommon(saveCount, op, doAA);
+        }
+
+        void initPath(int saveCount, const SkPath& path, SkClipOp op, bool doAA);
+
+        void setEmpty();
+
+        // All Element methods below are only used within SkClipStack.cpp
+        inline void checkEmpty() const;
+        inline bool canBeIntersectedInPlace(int saveCount, SkClipOp op) const;
+        /* This method checks to see if two rect clips can be safely merged into one. The issue here
+          is that to be strictly correct all the edges of the resulting rect must have the same
+          anti-aliasing. */
+        bool rectRectIntersectAllowed(const SkRect& newR, bool newAA) const;
+        /** Determines possible finite bounds for the Element given the previous element of the
+            stack */
+        void updateBoundAndGenID(const Element* prior);
+        // The different combination of fill & inverse fill when combining bounding boxes
+        enum FillCombo {
+            kPrev_Cur_FillCombo,
+            kPrev_InvCur_FillCombo,
+            kInvPrev_Cur_FillCombo,
+            kInvPrev_InvCur_FillCombo
+        };
+        // per-set operation functions used by updateBoundAndGenID().
+        inline void combineBoundsDiff(FillCombo combination, const SkRect& prevFinite);
+        inline void combineBoundsXOR(int combination, const SkRect& prevFinite);
+        inline void combineBoundsUnion(int combination, const SkRect& prevFinite);
+        inline void combineBoundsIntersection(int combination, const SkRect& prevFinite);
+        inline void combineBoundsRevDiff(int combination, const SkRect& prevFinite);
+    };
+
+    SkClipStack();
+    SkClipStack(const SkClipStack& b);
+    ~SkClipStack();
+
+    SkClipStack& operator=(const SkClipStack& b);
+    bool operator==(const SkClipStack& b) const;
+    bool operator!=(const SkClipStack& b) const { return !(*this == b); }
+
+    void reset();
+
+    int getSaveCount() const { return fSaveCount; }
+    void save();
+    void restore();
+
+    /**
+     * getBounds places the current finite bound in its first parameter. In its
+     * second, it indicates which kind of bound is being returned. If
+     * 'canvFiniteBound' is a normal bounding box then it encloses all writeable
+     * pixels. If 'canvFiniteBound' is an inside out bounding box then it
+     * encloses all the un-writeable pixels and the true/normal bound is the
+     * infinite plane. isIntersectionOfRects is an optional parameter
+     * that is true if 'canvFiniteBound' resulted from an intersection of rects.
+     */
+    void getBounds(SkRect* canvFiniteBound,
+                   BoundsType* boundType,
+                   bool* isIntersectionOfRects = NULL) const;
+
+    /**
+     * Returns true if the input (r)rect in device space is entirely contained
+     * by the clip. A return value of false does not guarantee that the (r)rect
+     * is not contained by the clip.
+     */
+    bool quickContains(const SkRect& devRect) const {
+        return this->isWideOpen() || this->internalQuickContains(devRect);
+    }
+
+    bool quickContains(const SkRRect& devRRect) const {
+        return this->isWideOpen() || this->internalQuickContains(devRRect);
+    }
+
+    /**
+     * Flattens the clip stack into a single SkPath. Returns true if any of
+     * the clip stack components requires anti-aliasing.
+     */
+    bool asPath(SkPath* path) const;
+
+    void clipDevRect(const SkIRect& ir, SkClipOp op) {
+        SkRect r;
+        r.set(ir);
+        this->clipRect(r, SkMatrix::I(), op, false);
+    }
+    void clipRect(const SkRect&, const SkMatrix& matrix, SkClipOp, bool doAA);
+    void clipRRect(const SkRRect&, const SkMatrix& matrix, SkClipOp, bool doAA);
+    void clipPath(const SkPath&, const SkMatrix& matrix, SkClipOp, bool doAA);
+    // An optimized version of clipDevRect(emptyRect, kIntersect, ...)
+    void clipEmpty();
+    void setDeviceClipRestriction(const SkIRect& rect) {
+        fClipRestrictionRect = SkRect::Make(rect);
+    }
+
+    /**
+     * isWideOpen returns true if the clip state corresponds to the infinite
+     * plane (i.e., draws are not limited at all)
+     */
+    bool isWideOpen() const { return this->getTopmostGenID() == kWideOpenGenID; }
+
+    /**
+     * This method quickly and conservatively determines whether the entire stack is equivalent to
+     * intersection with a rrect given a bounds, where the rrect must not contain the entire bounds.
+     *
+     * @param bounds   A bounds on what will be drawn through the clip. The clip only need be
+     *                 equivalent to a intersection with a rrect for draws within the bounds. The
+     *                 returned rrect must intersect the bounds but need not be contained by the
+     *                 bounds.
+     * @param rrect    If return is true rrect will contain the rrect equivalent to the stack.
+     * @param aa       If return is true aa will indicate whether the equivalent rrect clip is
+     *                 antialiased.
+     * @return true if the stack is equivalent to a single rrect intersect clip, false otherwise.
+     */
+    bool isRRect(const SkRect& bounds, SkRRect* rrect, bool* aa) const;
+
+    /**
+     * The generation ID has three reserved values to indicate special
+     * (potentially ignorable) cases
+     */
+    static const int32_t kInvalidGenID = 0;     //!< Invalid id that is never returned by
+                                                //!< SkClipStack. Useful when caching clips
+                                                //!< based on GenID.
+    static const int32_t kEmptyGenID = 1;       // no pixels writeable
+    static const int32_t kWideOpenGenID = 2;    // all pixels writeable
+
+    int32_t getTopmostGenID() const;
+
+#ifdef SK_DEBUG
+    /**
+     * Dumps the contents of the clip stack to SkDebugf. This is intended for Skia development
+     * debugging. Don't rely on the existence of this function or the formatting of its output.
+     */
+    void dump() const;
+#endif
+
+public:
+    class Iter {
+    public:
+        enum IterStart {
+            kBottom_IterStart = SkDeque::Iter::kFront_IterStart,
+            kTop_IterStart = SkDeque::Iter::kBack_IterStart
+        };
+
+        /**
+         * Creates an uninitialized iterator. Must be reset()
+         */
+        Iter();
+
+        Iter(const SkClipStack& stack, IterStart startLoc);
+
+        /**
+         *  Return the clip element for this iterator. If next()/prev() returns NULL, then the
+         *  iterator is done.
+         */
+        const Element* next();
+        const Element* prev();
+
+        /**
+         * Moves the iterator to the topmost element with the specified RegionOp and returns that
+         * element. If no clip element with that op is found, the first element is returned.
+         */
+        const Element* skipToTopmost(SkClipOp op);
+
+        /**
+         * Restarts the iterator on a clip stack.
+         */
+        void reset(const SkClipStack& stack, IterStart startLoc);
+
+    private:
+        const SkClipStack* fStack;
+        SkDeque::Iter      fIter;
+    };
+
+    /**
+     * The B2TIter iterates from the bottom of the stack to the top.
+     * It inherits privately from Iter to prevent access to reverse iteration.
+     */
+    class B2TIter : private Iter {
+    public:
+        B2TIter() {}
+
+        /**
+         * Wrap Iter's 2 parameter ctor to force initialization to the
+         * beginning of the deque/bottom of the stack
+         */
+        B2TIter(const SkClipStack& stack)
+        : INHERITED(stack, kBottom_IterStart) {
+        }
+
+        using Iter::next;
+
+        /**
+         * Wrap Iter::reset to force initialization to the
+         * beginning of the deque/bottom of the stack
+         */
+        void reset(const SkClipStack& stack) {
+            this->INHERITED::reset(stack, kBottom_IterStart);
+        }
+
+    private:
+
+        typedef Iter INHERITED;
+    };
+
+    /**
+     * GetConservativeBounds returns a conservative bound of the current clip.
+     * Since this could be the infinite plane (if inverse fills were involved) the
+     * maxWidth and maxHeight parameters can be used to limit the returned bound
+     * to the expected drawing area. Similarly, the offsetX and offsetY parameters
+     * allow the caller to offset the returned bound to account for translated
+     * drawing areas (i.e., those resulting from a saveLayer). For finite bounds,
+     * the translation (+offsetX, +offsetY) is applied before the clamp to the
+     * maximum rectangle: [0,maxWidth) x [0,maxHeight).
+     * isIntersectionOfRects is an optional parameter that is true when
+     * 'devBounds' is the result of an intersection of rects. In this case
+     * 'devBounds' is the exact answer/clip.
+     */
+    void getConservativeBounds(int offsetX,
+                               int offsetY,
+                               int maxWidth,
+                               int maxHeight,
+                               SkRect* devBounds,
+                               bool* isIntersectionOfRects = NULL) const;
+
+private:
+    friend class Iter;
+
+    SkDeque fDeque;
+    int     fSaveCount;
+
+    // Generation ID for the clip stack. This is incremented for each
+    // clipDevRect and clipDevPath call. 0 is reserved to indicate an
+    // invalid ID.
+    static int32_t     gGenID;
+    SkRect fClipRestrictionRect = SkRect::MakeEmpty();
+
+    bool internalQuickContains(const SkRect& devRect) const;
+    bool internalQuickContains(const SkRRect& devRRect) const;
+
+    /**
+     * Helper for clipDevPath, etc.
+     */
+    void pushElement(const Element& element);
+
+    /**
+     * Restore the stack back to the specified save count.
+     */
+    void restoreTo(int saveCount);
+
+    inline bool hasClipRestriction(SkClipOp op) {
+        return op >= SkClipOp::kUnion_deprecated && !fClipRestrictionRect.isEmpty();
+    }
+
+    /**
+     * Return the next unique generation ID.
+     */
+    static int32_t GetNextGenID();
+};
+
+#endif