add pathops debugging

src/pathops/SkOpSegment.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkOpCoincidence.h"
 #include "SkOpContour.h"
 #include "SkOpSegment.h"
 #include "SkPathWriter.h"
 
-#define FAIL_IF(cond) do { if (cond) return false; } while (false)
-
 /*
 After computing raw intersections, post process all segments to:
 - find small collections of points that can be collapsed to a single point
 - find missing intersections to resolve differences caused by different algorithms
 
 Consider segments containing tiny or small intervals. Consider coincident segments
 because coincidence finds intersections through distance measurement that non-coincident
 intersection tests cannot.
  */
 
@@ skipping 132 matching lines @@
     int maxWinding;
     setUpWinding(start, end, &maxWinding, sumWinding);
     bool from = maxWinding != 0;
     bool to = *sumWinding  != 0;
     bool result = gUnaryActiveEdge[from][to];
     return result;
 }
 
 bool SkOpSegment::addCurveTo(const SkOpSpanBase* start, const SkOpSpanBase* end,
         SkPathWriter* path) const {
-    if (start->starter(end)->alreadyAdded()) {
-        SkDEBUGF(("same curve added twice aborted pathops\n"));
-        return false;
-    }
+    FAIL_IF(start->starter(end)->alreadyAdded());
     SkOpCurve edge;
     const SkPoint* ePtr;
     SkScalar eWeight;
     if ((start == &fHead && end == &fTail) || (start == &fTail && end == &fHead)) {
         ePtr = fPts;
         eWeight = fWeight;
     } else {
     // OPTIMIZE? if not active, skip remainder and return xyAtT(end)
         subDivide(start, end, &edge);
         ePtr = edge.fPts;
@@ skipping 1610 matching lines @@
     int absOut = SkTAbs(outerWinding);
     int absIn = SkTAbs(innerWinding);
     bool result = absOut == absIn ? outerWinding < 0 : absOut < absIn;
     return result;
 }
 
 int SkOpSegment::windSum(const SkOpAngle* angle) const {
     const SkOpSpan* minSpan = angle->start()->starter(angle->end());
     return minSpan->windSum();
 }