2 files changed, 84 insertions, 0 deletions
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index a95a5993e9..c19fd2f463 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -20,6 +20,7 @@
 #include "SkTypes.h"
 #include "SkBitmap.h"
 #include "SkDeque.h"
+#include "SkClipStack.h"
 #include "SkPaint.h"
 #include "SkRefCnt.h"
 #include "SkPath.h"
@@ -776,6 +777,7 @@ protected:
 private:
     class MCRec;
 
+    SkClipStack fClipStack;
     SkDeque     fMCStack;
     // points to top of stack
     MCRec*      fMCRec;
@@ -835,6 +837,23 @@ private:
 
     SkMatrix    fExternalMatrix, fExternalInverse;
     bool        fUseExternalMatrix;
+
+    class AutoValidateClip : ::SkNoncopyable {
+    public:
+        explicit AutoValidateClip(SkCanvas* canvas) : fCanvas(canvas) {
+            fCanvas->validateClip();
+        }
+        ~AutoValidateClip() { fCanvas->validateClip(); }
+
+    private:
+        const SkCanvas* fCanvas;
+    };
+
+#ifdef SK_DEBUG
+    void validateClip() const;
+#else
+    void validateClip() const {}
+#endif
 };
 
 /** Stack helper class to automatically call restoreToCount() on the canvas
diff --git a/include/core/SkClipStack.h b/include/core/SkClipStack.h
new file mode 100644
index 0000000000..bd64d66df8
--- /dev/null
+++ b/include/core/SkClipStack.h
@@ -0,0 +1,65 @@
+#ifndef SkClipStack_DEFINED
+#define SkClipStack_DEFINED
+
+#include "SkDeque.h"
+#include "SkRegion.h"
+
+class SkRect;
+class SkPath;
+
+class SkClipStack {
+public:
+    SkClipStack();
+    ~SkClipStack() {}
+
+    void reset();
+
+    int getSaveCount() const { return fSaveCount; }
+    void save();
+    void restore();
+
+    void clipDevRect(const SkIRect& ir,
+                     SkRegion::Op op = SkRegion::kIntersect_Op) {
+        SkRect r;
+        r.set(ir);
+        this->clipDevRect(r, op);
+    }
+    void clipDevRect(const SkRect&, SkRegion::Op = SkRegion::kIntersect_Op);
+    void clipDevPath(const SkPath&, SkRegion::Op = SkRegion::kIntersect_Op);
+
+    class B2FIter {
+    public:
+        B2FIter(const SkClipStack& stack);
+
+        struct Clip {
+            const SkRect*   fRect;  // if non-null, this is a rect clip
+            const SkPath*   fPath;  // if non-null, this is a path clip
+            SkRegion::Op    fOp;
+        };
+
+        /**
+         *  Return the clip for this element in the iterator. If next() returns
+         *  NULL, then the iterator is done. The type of clip is determined by
+         *  the pointers fRect and fPath:
+         *
+         *  fRect==NULL  fPath!=NULL    path clip
+         *  fRect!=NULL  fPath==NULL    rect clip
+         *  fRect==NULL  fPath==NULL    empty clip
+         */
+        const Clip* next();
+
+    private:
+        Clip             fClip;
+        SkDeque::F2BIter fIter;
+    };
+
+private:
+    friend class B2FIter;
+    struct Rec;
+
+    SkDeque fDeque;
+    int     fSaveCount;
+};
+
+#endif
+