move SkPathRef.h into private

Bug: skia:
Change-Id: I3370c594301ae833ec1fe3cb16ac544e5b2128e8
Reviewed-on: https://skia-review.googlesource.com/18982
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

1 files changed, 548 insertions, 0 deletions

diff --git a/include/private/SkPathRef.h b/include/private/SkPathRef.h
new file mode 100644
index 0000000000..5e6fda7d85
--- /dev/null
+++ b/include/private/SkPathRef.h
@@ -0,0 +1,548 @@
+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPathRef_DEFINED
+#define SkPathRef_DEFINED
+
+#include "../private/SkAtomics.h"
+#include "../private/SkTDArray.h"
+#include "SkMatrix.h"
+#include "SkPoint.h"
+#include "SkRRect.h"
+#include "SkRect.h"
+#include "SkRefCnt.h"
+#include <stddef.h> // ptrdiff_t
+
+class SkRBuffer;
+class SkWBuffer;
+
+/**
+ * Holds the path verbs and points. It is versioned by a generation ID. None of its public methods
+ * modify the contents. To modify or append to the verbs/points wrap the SkPathRef in an
+ * SkPathRef::Editor object. Installing the editor resets the generation ID. It also performs
+ * copy-on-write if the SkPathRef is shared by multiple SkPaths. The caller passes the Editor's
+ * constructor a pointer to a sk_sp<SkPathRef>, which may be updated to point to a new SkPathRef
+ * after the editor's constructor returns.
+ *
+ * The points and verbs are stored in a single allocation. The points are at the begining of the
+ * allocation while the verbs are stored at end of the allocation, in reverse order. Thus the points
+ * and verbs both grow into the middle of the allocation until the meet. To access verb i in the
+ * verb array use ref.verbs()[~i] (because verbs() returns a pointer just beyond the first
+ * logical verb or the last verb in memory).
+ */
+
+class SK_API SkPathRef final : public SkNVRefCnt<SkPathRef> {
+public:
+    class Editor {
+    public:
+        Editor(sk_sp<SkPathRef>* pathRef,
+               int incReserveVerbs = 0,
+               int incReservePoints = 0);
+
+        ~Editor() { SkDEBUGCODE(sk_atomic_dec(&fPathRef->fEditorsAttached);) }
+
+        /**
+         * Returns the array of points.
+         */
+        SkPoint* points() { return fPathRef->getPoints(); }
+        const SkPoint* points() const { return fPathRef->points(); }
+
+        /**
+         * Gets the ith point. Shortcut for this->points() + i
+         */
+        SkPoint* atPoint(int i) {
+            SkASSERT((unsigned) i < (unsigned) fPathRef->fPointCnt);
+            return this->points() + i;
+        }
+        const SkPoint* atPoint(int i) const {
+            SkASSERT((unsigned) i < (unsigned) fPathRef->fPointCnt);
+            return this->points() + i;
+        }
+
+        /**
+         * Adds the verb and allocates space for the number of points indicated by the verb. The
+         * return value is a pointer to where the points for the verb should be written.
+         * 'weight' is only used if 'verb' is kConic_Verb
+         */
+        SkPoint* growForVerb(int /*SkPath::Verb*/ verb, SkScalar weight = 0) {
+            SkDEBUGCODE(fPathRef->validate();)
+            return fPathRef->growForVerb(verb, weight);
+        }
+
+        /**
+         * Allocates space for multiple instances of a particular verb and the
+         * requisite points & weights.
+         * The return pointer points at the first new point (indexed normally [<i>]).
+         * If 'verb' is kConic_Verb, 'weights' will return a pointer to the
+         * space for the conic weights (indexed normally).
+         */
+        SkPoint* growForRepeatedVerb(int /*SkPath::Verb*/ verb,
+                                     int numVbs,
+                                     SkScalar** weights = NULL) {
+            return fPathRef->growForRepeatedVerb(verb, numVbs, weights);
+        }
+
+        /**
+         * Resets the path ref to a new verb and point count. The new verbs and points are
+         * uninitialized.
+         */
+        void resetToSize(int newVerbCnt, int newPointCnt, int newConicCount) {
+            fPathRef->resetToSize(newVerbCnt, newPointCnt, newConicCount);
+        }
+
+        /**
+         * Gets the path ref that is wrapped in the Editor.
+         */
+        SkPathRef* pathRef() { return fPathRef; }
+
+        void setIsOval(bool isOval, bool isCCW, unsigned start) {
+            fPathRef->setIsOval(isOval, isCCW, start);
+        }
+
+        void setIsRRect(bool isRRect, bool isCCW, unsigned start) {
+            fPathRef->setIsRRect(isRRect, isCCW, start);
+        }
+
+        void setBounds(const SkRect& rect) { fPathRef->setBounds(rect); }
+
+    private:
+        SkPathRef* fPathRef;
+    };
+
+    class SK_API Iter {
+    public:
+        Iter();
+        Iter(const SkPathRef&);
+
+        void setPathRef(const SkPathRef&);
+
+        /** Return the next verb in this iteration of the path. When all
+            segments have been visited, return kDone_Verb.
+
+            @param  pts The points representing the current verb and/or segment
+                        This must not be NULL.
+            @return The verb for the current segment
+        */
+        uint8_t next(SkPoint pts[4]);
+        uint8_t peek() const;
+
+        SkScalar conicWeight() const { return *fConicWeights; }
+
+    private:
+        const SkPoint*  fPts;
+        const uint8_t*  fVerbs;
+        const uint8_t*  fVerbStop;
+        const SkScalar* fConicWeights;
+    };
+
+public:
+    /**
+     * Gets a path ref with no verbs or points.
+     */
+    static SkPathRef* CreateEmpty();
+
+    /**
+     *  Returns true if all of the points in this path are finite, meaning there
+     *  are no infinities and no NaNs.
+     */
+    bool isFinite() const {
+        if (fBoundsIsDirty) {
+            this->computeBounds();
+        }
+        return SkToBool(fIsFinite);
+    }
+
+    /**
+     *  Returns a mask, where each bit corresponding to a SegmentMask is
+     *  set if the path contains 1 or more segments of that type.
+     *  Returns 0 for an empty path (no segments).
+     */
+    uint32_t getSegmentMasks() const { return fSegmentMask; }
+
+    /** Returns true if the path is an oval.
+     *
+     * @param rect      returns the bounding rect of this oval. It's a circle
+     *                  if the height and width are the same.
+     * @param isCCW     is the oval CCW (or CW if false).
+     * @param start     indicates where the contour starts on the oval (see
+     *                  SkPath::addOval for intepretation of the index).
+     *
+     * @return true if this path is an oval.
+     *              Tracking whether a path is an oval is considered an
+     *              optimization for performance and so some paths that are in
+     *              fact ovals can report false.
+     */
+    bool isOval(SkRect* rect, bool* isCCW, unsigned* start) const {
+        if (fIsOval) {
+            if (rect) {
+                *rect = this->getBounds();
+            }
+            if (isCCW) {
+                *isCCW = SkToBool(fRRectOrOvalIsCCW);
+            }
+            if (start) {
+                *start = fRRectOrOvalStartIdx;
+            }
+        }
+
+        return SkToBool(fIsOval);
+    }
+
+    bool isRRect(SkRRect* rrect, bool* isCCW, unsigned* start) const {
+        if (fIsRRect) {
+            if (rrect) {
+                *rrect = this->getRRect();
+            }
+            if (isCCW) {
+                *isCCW = SkToBool(fRRectOrOvalIsCCW);
+            }
+            if (start) {
+                *start = fRRectOrOvalStartIdx;
+            }
+        }
+        return SkToBool(fIsRRect);
+    }
+
+
+    bool hasComputedBounds() const {
+        return !fBoundsIsDirty;
+    }
+
+    /** Returns the bounds of the path's points. If the path contains 0 or 1
+        points, the bounds is set to (0,0,0,0), and isEmpty() will return true.
+        Note: this bounds may be larger than the actual shape, since curves
+        do not extend as far as their control points.
+    */
+    const SkRect& getBounds() const {
+        if (fBoundsIsDirty) {
+            this->computeBounds();
+        }
+        return fBounds;
+    }
+
+    SkRRect getRRect() const;
+
+    /**
+     * Transforms a path ref by a matrix, allocating a new one only if necessary.
+     */
+    static void CreateTransformedCopy(sk_sp<SkPathRef>* dst,
+                                      const SkPathRef& src,
+                                      const SkMatrix& matrix);
+
+    static SkPathRef* CreateFromBuffer(SkRBuffer* buffer);
+
+    /**
+     * Rollsback a path ref to zero verbs and points with the assumption that the path ref will be
+     * repopulated with approximately the same number of verbs and points. A new path ref is created
+     * only if necessary.
+     */
+    static void Rewind(sk_sp<SkPathRef>* pathRef);
+
+    ~SkPathRef();
+    int countPoints() const { SkDEBUGCODE(this->validate();) return fPointCnt; }
+    int countVerbs() const { SkDEBUGCODE(this->validate();) return fVerbCnt; }
+    int countWeights() const { SkDEBUGCODE(this->validate();) return fConicWeights.count(); }
+
+    /**
+     * Returns a pointer one beyond the first logical verb (last verb in memory order).
+     */
+    const uint8_t* verbs() const { SkDEBUGCODE(this->validate();) return fVerbs; }
+
+    /**
+     * Returns a const pointer to the first verb in memory (which is the last logical verb).
+     */
+    const uint8_t* verbsMemBegin() const { return this->verbs() - fVerbCnt; }
+
+    /**
+     * Returns a const pointer to the first point.
+     */
+    const SkPoint* points() const { SkDEBUGCODE(this->validate();) return fPoints; }
+
+    /**
+     * Shortcut for this->points() + this->countPoints()
+     */
+    const SkPoint* pointsEnd() const { return this->points() + this->countPoints(); }
+
+    const SkScalar* conicWeights() const { SkDEBUGCODE(this->validate();) return fConicWeights.begin(); }
+    const SkScalar* conicWeightsEnd() const { SkDEBUGCODE(this->validate();) return fConicWeights.end(); }
+
+    /**
+     * Convenience methods for getting to a verb or point by index.
+     */
+    uint8_t atVerb(int index) const {
+        SkASSERT((unsigned) index < (unsigned) fVerbCnt);
+        return this->verbs()[~index];
+    }
+    const SkPoint& atPoint(int index) const {
+        SkASSERT((unsigned) index < (unsigned) fPointCnt);
+        return this->points()[index];
+    }
+
+    bool operator== (const SkPathRef& ref) const;
+
+    /**
+     * Writes the path points and verbs to a buffer.
+     */
+    void writeToBuffer(SkWBuffer* buffer) const;
+
+    /**
+     * Gets the number of bytes that would be written in writeBuffer()
+     */
+    uint32_t writeSize() const;
+
+    void interpolate(const SkPathRef& ending, SkScalar weight, SkPathRef* out) const;
+
+    /**
+     * Gets an ID that uniquely identifies the contents of the path ref. If two path refs have the
+     * same ID then they have the same verbs and points. However, two path refs may have the same
+     * contents but different genIDs.
+     */
+    uint32_t genID() const;
+
+    struct GenIDChangeListener {
+        virtual ~GenIDChangeListener() {}
+        virtual void onChange() = 0;
+    };
+
+    void addGenIDChangeListener(GenIDChangeListener* listener);
+
+    SkDEBUGCODE(void validate() const;)
+
+private:
+    enum SerializationOffsets {
+        kRRectOrOvalStartIdx_SerializationShift = 28,  // requires 3 bits
+        kRRectOrOvalIsCCW_SerializationShift = 27,     // requires 1 bit
+        kIsRRect_SerializationShift = 26,              // requires 1 bit
+        kIsFinite_SerializationShift = 25,             // requires 1 bit
+        kIsOval_SerializationShift = 24,               // requires 1 bit
+        kSegmentMask_SerializationShift = 0            // requires 4 bits
+    };
+
+    SkPathRef() {
+        fBoundsIsDirty = true;    // this also invalidates fIsFinite
+        fPointCnt = 0;
+        fVerbCnt = 0;
+        fVerbs = NULL;
+        fPoints = NULL;
+        fFreeSpace = 0;
+        fGenerationID = kEmptyGenID;
+        fSegmentMask = 0;
+        fIsOval = false;
+        fIsRRect = false;
+        // The next two values don't matter unless fIsOval or fIsRRect are true.
+        fRRectOrOvalIsCCW = false;
+        fRRectOrOvalStartIdx = 0xAC;
+        SkDEBUGCODE(fEditorsAttached = 0;)
+        SkDEBUGCODE(this->validate();)
+    }
+
+    void copy(const SkPathRef& ref, int additionalReserveVerbs, int additionalReservePoints);
+
+    // Return true if the computed bounds are finite.
+    static bool ComputePtBounds(SkRect* bounds, const SkPathRef& ref) {
+        return bounds->setBoundsCheck(ref.points(), ref.countPoints());
+    }
+
+    // called, if dirty, by getBounds()
+    void computeBounds() const {
+        SkDEBUGCODE(this->validate();)
+        // TODO(mtklein): remove fBoundsIsDirty and fIsFinite,
+        // using an inverted rect instead of fBoundsIsDirty and always recalculating fIsFinite.
+        SkASSERT(fBoundsIsDirty);
+
+        fIsFinite = ComputePtBounds(&fBounds, *this);
+        fBoundsIsDirty = false;
+    }
+
+    void setBounds(const SkRect& rect) {
+        SkASSERT(rect.fLeft <= rect.fRight && rect.fTop <= rect.fBottom);
+        fBounds = rect;
+        fBoundsIsDirty = false;
+        fIsFinite = fBounds.isFinite();
+    }
+
+    /** Makes additional room but does not change the counts or change the genID */
+    void incReserve(int additionalVerbs, int additionalPoints) {
+        SkDEBUGCODE(this->validate();)
+        size_t space = additionalVerbs * sizeof(uint8_t) + additionalPoints * sizeof (SkPoint);
+        this->makeSpace(space);
+        SkDEBUGCODE(this->validate();)
+    }
+
+    /** Resets the path ref with verbCount verbs and pointCount points, all uninitialized. Also
+     *  allocates space for reserveVerb additional verbs and reservePoints additional points.*/
+    void resetToSize(int verbCount, int pointCount, int conicCount,
+                     int reserveVerbs = 0, int reservePoints = 0) {
+        SkDEBUGCODE(this->validate();)
+        fBoundsIsDirty = true;      // this also invalidates fIsFinite
+        fGenerationID = 0;
+
+        fSegmentMask = 0;
+        fIsOval = false;
+        fIsRRect = false;
+
+        size_t newSize = sizeof(uint8_t) * verbCount + sizeof(SkPoint) * pointCount;
+        size_t newReserve = sizeof(uint8_t) * reserveVerbs + sizeof(SkPoint) * reservePoints;
+        size_t minSize = newSize + newReserve;
+
+        ptrdiff_t sizeDelta = this->currSize() - minSize;
+
+        if (sizeDelta < 0 || static_cast<size_t>(sizeDelta) >= 3 * minSize) {
+            sk_free(fPoints);
+            fPoints = NULL;
+            fVerbs = NULL;
+            fFreeSpace = 0;
+            fVerbCnt = 0;
+            fPointCnt = 0;
+            this->makeSpace(minSize);
+            fVerbCnt = verbCount;
+            fPointCnt = pointCount;
+            fFreeSpace -= newSize;
+        } else {
+            fPointCnt = pointCount;
+            fVerbCnt = verbCount;
+            fFreeSpace = this->currSize() - minSize;
+        }
+        fConicWeights.setCount(conicCount);
+        SkDEBUGCODE(this->validate();)
+    }
+
+    /**
+     * Increases the verb count by numVbs and point count by the required amount.
+     * The new points are uninitialized. All the new verbs are set to the specified
+     * verb. If 'verb' is kConic_Verb, 'weights' will return a pointer to the
+     * uninitialized conic weights.
+     */
+    SkPoint* growForRepeatedVerb(int /*SkPath::Verb*/ verb, int numVbs, SkScalar** weights);
+
+    /**
+     * Increases the verb count 1, records the new verb, and creates room for the requisite number
+     * of additional points. A pointer to the first point is returned. Any new points are
+     * uninitialized.
+     */
+    SkPoint* growForVerb(int /*SkPath::Verb*/ verb, SkScalar weight);
+
+    /**
+     * Ensures that the free space available in the path ref is >= size. The verb and point counts
+     * are not changed.
+     */
+    void makeSpace(size_t size) {
+        SkDEBUGCODE(this->validate();)
+        ptrdiff_t growSize = size - fFreeSpace;
+        if (growSize <= 0) {
+            return;
+        }
+        size_t oldSize = this->currSize();
+        // round to next multiple of 8 bytes
+        growSize = (growSize + 7) & ~static_cast<size_t>(7);
+        // we always at least double the allocation
+        if (static_cast<size_t>(growSize) < oldSize) {
+            growSize = oldSize;
+        }
+        if (growSize < kMinSize) {
+            growSize = kMinSize;
+        }
+        size_t newSize = oldSize + growSize;
+        // Note that realloc could memcpy more than we need. It seems to be a win anyway. TODO:
+        // encapsulate this.
+        fPoints = reinterpret_cast<SkPoint*>(sk_realloc_throw(fPoints, newSize));
+        size_t oldVerbSize = fVerbCnt * sizeof(uint8_t);
+        void* newVerbsDst = reinterpret_cast<void*>(
+                                reinterpret_cast<intptr_t>(fPoints) + newSize - oldVerbSize);
+        void* oldVerbsSrc = reinterpret_cast<void*>(
+                                reinterpret_cast<intptr_t>(fPoints) + oldSize - oldVerbSize);
+        memmove(newVerbsDst, oldVerbsSrc, oldVerbSize);
+        fVerbs = reinterpret_cast<uint8_t*>(reinterpret_cast<intptr_t>(fPoints) + newSize);
+        fFreeSpace += growSize;
+        SkDEBUGCODE(this->validate();)
+    }
+
+    /**
+     * Private, non-const-ptr version of the public function verbsMemBegin().
+     */
+    uint8_t* verbsMemWritable() {
+        SkDEBUGCODE(this->validate();)
+        return fVerbs - fVerbCnt;
+    }
+
+    /**
+     * Gets the total amount of space allocated for verbs, points, and reserve.
+     */
+    size_t currSize() const {
+        return reinterpret_cast<intptr_t>(fVerbs) - reinterpret_cast<intptr_t>(fPoints);
+    }
+
+    /**
+     * Called the first time someone calls CreateEmpty to actually create the singleton.
+     */
+    friend SkPathRef* sk_create_empty_pathref();
+
+    void setIsOval(bool isOval, bool isCCW, unsigned start) {
+        fIsOval = isOval;
+        fRRectOrOvalIsCCW = isCCW;
+        fRRectOrOvalStartIdx = start;
+    }
+
+    void setIsRRect(bool isRRect, bool isCCW, unsigned start) {
+        fIsRRect = isRRect;
+        fRRectOrOvalIsCCW = isCCW;
+        fRRectOrOvalStartIdx = start;
+    }
+
+    // called only by the editor. Note that this is not a const function.
+    SkPoint* getPoints() {
+        SkDEBUGCODE(this->validate();)
+        fIsOval = false;
+        fIsRRect = false;
+        return fPoints;
+    }
+
+    const SkPoint* getPoints() const {
+        SkDEBUGCODE(this->validate();)
+        return fPoints;
+    }
+
+    void callGenIDChangeListeners();
+
+    enum {
+        kMinSize = 256,
+    };
+
+    mutable SkRect   fBounds;
+
+    SkPoint*            fPoints; // points to begining of the allocation
+    uint8_t*            fVerbs; // points just past the end of the allocation (verbs grow backwards)
+    int                 fVerbCnt;
+    int                 fPointCnt;
+    size_t              fFreeSpace; // redundant but saves computation
+    SkTDArray<SkScalar> fConicWeights;
+
+    enum {
+        kEmptyGenID = 1, // GenID reserved for path ref with zero points and zero verbs.
+    };
+    mutable uint32_t    fGenerationID;
+    SkDEBUGCODE(int32_t fEditorsAttached;) // assert that only one editor in use at any time.
+
+    SkTDArray<GenIDChangeListener*> fGenIDChangeListeners;  // pointers are owned
+
+    mutable uint8_t  fBoundsIsDirty;
+    mutable SkBool8  fIsFinite;    // only meaningful if bounds are valid
+
+    SkBool8  fIsOval;
+    SkBool8  fIsRRect;
+    // Both the circle and rrect special cases have a notion of direction and starting point
+    // The next two variables store that information for either.
+    SkBool8  fRRectOrOvalIsCCW;
+    uint8_t  fRRectOrOvalStartIdx;
+    uint8_t  fSegmentMask;
+
+    friend class PathRefTest_Private;
+    friend class ForceIsRRect_Private; // unit test isRRect
+};
+
+#endif