SK_ONCE for SkData

src/core/SkPathRef.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBuffer.h"
+#include "SkOnce.h"
 #include "SkPath.h"
 #include "SkPathRef.h"
 
 SK_DEFINE_INST_COUNT(SkPathRef);
 
 //////////////////////////////////////////////////////////////////////////////
 SkPathRef::Editor::Editor(SkAutoTUnref<SkPathRef>* pathRef,
                           int incReserveVerbs,
                           int incReservePoints)
 {
@@ skipping 10 matching lines @@
 }
 
 SkPoint* SkPathRef::Editor::growForConic(SkScalar w) {
     SkDEBUGCODE(fPathRef->validate();)
     SkPoint* pts = fPathRef->growForVerb(SkPath::kConic_Verb);
     *fPathRef->fConicWeights.append() = w;
     return pts;
 }
 
 //////////////////////////////////////////////////////////////////////////////
+void SkPathRef::CreateEmptyImpl(SkPathRef** empty) {
+    *empty = SkNEW(SkPathRef);
+    (*empty)->computeBounds();  // Preemptively avoid a race to clear fBoundsIsDirty.
+}
+
+SkPathRef* SkPathRef::CreateEmpty() {
+    static SkPathRef* gEmptyPathRef;
+    SK_DECLARE_STATIC_ONCE(once);
+    SkOnce(&once, SkPathRef::CreateEmptyImpl, &gEmptyPathRef);
+    return SkRef(gEmptyPathRef);
+}
+
 void SkPathRef::CreateTransformedCopy(SkAutoTUnref<SkPathRef>* dst,
                                       const SkPathRef& src,
                                       const SkMatrix& matrix) {
     SkDEBUGCODE(src.validate();)
     if (matrix.isIdentity()) {
         if (*dst != &src) {
             src.ref();
             dst->reset(const_cast<SkPathRef*>(&src));
             SkDEBUGCODE((*dst)->validate();)
         }
@@ skipping 267 matching lines @@
                      fPoints[i].fY - fBounds.fBottom < SK_ScalarNearlyZero);
             if (!fPoints[i].isFinite()) {
                 isFinite = false;
             }
         }
         SkASSERT(SkToBool(fIsFinite) == isFinite);
     }
 #endif
 }
 #endif