fail early if coincidence can't be resolved

src/pathops/SkOpContour.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkOpContour_DEFINED
 #define SkOpContour_DEFINED
 
 #include "SkOpSegment.h"
@@ skipping 96 matching lines @@
     }
 
     void alignTPt(int segmentIndex, const SkOpContour* other, int otherIndex,
                   bool swap, int tIndex, SkIntersections* ts, SkPoint* point) const;
 
     const SkPathOpsBounds& bounds() const {
         return fBounds;
     }
 
     bool calcAngles();
-    void calcCoincidentWinding();
+    bool calcCoincidentWinding();
     void calcPartialCoincidentWinding();
 
     void checkDuplicates() {
         int segmentCount = fSegments.count();
         for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
             SkOpSegment& segment = fSegments[sIndex];
             if (segment.count() > 2) {
                 segment.checkDuplicates();
             }
         }
@@ skipping 190 matching lines @@
     void dumpCoincidence(const SkCoincidence& ) const;
     void dumpCoincidences() const;
     void dumpPt(int ) const;
     void dumpPts() const;
     void dumpSpan(int ) const;
     void dumpSpans() const;
 
 private:
     void alignPt(int index, SkPoint* point, int zeroPt) const;
     int alignT(bool swap, int tIndex, SkIntersections* ts) const;
-    void calcCommonCoincidentWinding(const SkCoincidence& );
+    bool calcCommonCoincidentWinding(const SkCoincidence& );
     void checkCoincidentPair(const SkCoincidence& oneCoin, int oneIdx,
                              const SkCoincidence& twoCoin, int twoIdx, bool partial);
     void joinCoincidence(const SkTArray<SkCoincidence, true>& , bool partial);
     void setBounds();
 
     SkTArray<SkOpSegment> fSegments;
     SkTArray<SkOpSegment*, true> fSortedSegments;
     int fFirstSorted;
     SkTArray<SkCoincidence, true> fCoincidences;
     SkTArray<SkCoincidence, true> fPartialCoincidences;
     SkTArray<const SkOpContour*, true> fCrosses;
     SkPathOpsBounds fBounds;
     bool fContainsIntercepts;  // FIXME: is this used by anybody?
     bool fContainsCubics;
     bool fContainsCurves;
     bool fDone;
     bool fMultiples;  // set if some segment has multiple identical intersections with other curves
     bool fOperand;  // true for the second argument to a binary operator
     bool fXor;
     bool fOppXor;
 #if defined(SK_DEBUG) || !FORCE_RELEASE
     int debugID() const { return fID; }
     int fID;
 #else
     int debugID() const { return -1; }
 #endif
 };
 
 #endif