1 files changed, 144 insertions, 0 deletions
diff --git a/src/core/SkClipStack.cpp b/src/core/SkClipStack.cpp
new file mode 100644
index 0000000000..2b63aea9a0
--- /dev/null
+++ b/src/core/SkClipStack.cpp
@@ -0,0 +1,144 @@
+#include "SkClipStack.h"
+#include "SkPath.h"
+#include <new>
+
+struct SkClipStack::Rec {
+    enum State {
+        kEmpty_State,
+        kRect_State,
+        kPath_State
+    };
+
+    SkPath          fPath;
+    SkRect          fRect;
+    int             fSaveCount;
+    SkRegion::Op    fOp;
+    State           fState;
+
+    Rec(int saveCount, const SkRect& rect, SkRegion::Op op) : fRect(rect) {
+        fSaveCount = saveCount;
+        fOp = op;
+        fState = kRect_State;
+    }
+
+    Rec(int saveCount, const SkPath& path, SkRegion::Op op) : fPath(path) {
+        fSaveCount = saveCount;
+        fOp = op;
+        fState = kPath_State;
+    }
+
+    /**
+     *  Returns true if this Rec can be intersected in place with a new clip
+     */
+    bool canBeIntersected(int saveCount, SkRegion::Op op) const {
+        if (kEmpty_State == fState) {
+            return true;
+        }
+        return  fSaveCount == saveCount &&
+                SkRegion::kIntersect_Op == fOp &&
+                SkRegion::kIntersect_Op == op;
+    }
+};
+
+SkClipStack::SkClipStack() : fDeque(sizeof(Rec)) {
+    fSaveCount = 0;
+}
+
+void SkClipStack::reset() {
+    // don't have a reset() on SkDeque, so fake it here
+    fDeque.~SkDeque();
+    new (&fDeque) SkDeque(sizeof(Rec));
+
+    fSaveCount = 0;
+}
+
+void SkClipStack::save() {
+    fSaveCount += 1;
+}
+
+void SkClipStack::restore() {
+    fSaveCount -= 1;
+    while (!fDeque.empty()) {
+        Rec* rec = (Rec*)fDeque.back();
+        if (rec->fSaveCount <= fSaveCount) {
+            break;
+        }
+        rec->~Rec();
+        fDeque.pop_back();
+    }
+}
+
+void SkClipStack::clipDevRect(const SkRect& rect, SkRegion::Op op) {
+    Rec* rec = (Rec*)fDeque.back();
+    if (rec && rec->canBeIntersected(fSaveCount, op)) {
+        switch (rec->fState) {
+            case Rec::kEmpty_State:
+                return;
+            case Rec::kRect_State:
+                if (!rec->fRect.intersect(rect)) {
+                    rec->fState = Rec::kEmpty_State;
+                }
+                return;
+            case Rec::kPath_State:
+                if (!SkRect::Intersects(rec->fPath.getBounds(), rect)) {
+                    rec->fState = Rec::kEmpty_State;
+                    return;
+                }
+                break;
+        }
+    }
+    new (fDeque.push_back()) Rec(fSaveCount, rect, op);
+}
+
+void SkClipStack::clipDevPath(const SkPath& path, SkRegion::Op op) {
+    Rec* rec = (Rec*)fDeque.back();
+    if (rec && rec->canBeIntersected(fSaveCount, op)) {
+        const SkRect& pathBounds = path.getBounds();
+        switch (rec->fState) {
+            case Rec::kEmpty_State:
+                return;
+            case Rec::kRect_State:
+                if (!SkRect::Intersects(rec->fRect, pathBounds)) {
+                    rec->fState = Rec::kEmpty_State;
+                    return;
+                }
+                break;
+            case Rec::kPath_State:
+                if (!SkRect::Intersects(rec->fPath.getBounds(), pathBounds)) {
+                    rec->fState = Rec::kEmpty_State;
+                    return;
+                }
+                break;
+        }
+    }
+    new (fDeque.push_back()) Rec(fSaveCount, path, op);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkClipStack::B2FIter::B2FIter(const SkClipStack& stack) : fIter(stack.fDeque) {
+}
+
+const SkClipStack::B2FIter::Clip* SkClipStack::B2FIter::next() {
+    const SkClipStack::Rec* rec = (const SkClipStack::Rec*)fIter.next();
+    if (NULL == rec) {
+        return NULL;
+    }
+
+    switch (rec->fState) {
+        case SkClipStack::Rec::kEmpty_State:
+            fClip.fRect = NULL;
+            fClip.fPath = NULL;
+            break;
+        case SkClipStack::Rec::kRect_State:
+            fClip.fRect = &rec->fRect;
+            fClip.fPath = NULL;
+            break;
+        case SkClipStack::Rec::kPath_State:
+            fClip.fRect = NULL;
+            fClip.fPath = &rec->fPath;
+            break;
+    }
+    fClip.fOp = rec->fOp;
+    return &fClip;
+}