Move SkTDStackNester into its own private file.

experimental/PdfViewer/src/SkTDStackNester.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 SkTDStackNester_DEFINED
+#define SkTDStackNester_DEFINED
+
+#include "SkTypes.h"
+
+// Adobe limits it to 28, so 256 should be more than enough
+#define MAX_NESTING 256
+
+/** \class SkTDStackNester
+ *
+ * The difference between SkTDStackNester and SkTDStack is that:
+ *   - SkTDStackNester uses new/delete to manage initializations
+ *   - Supports nest/unnest which simulates a stack of stack. unnest will pop all the
+ *     objects pushed since the last nest
+ */
+
+template <typename T> class SkTDStackNester : SkNoncopyable {
+public:
+    SkTDStackNester() : fCount(0), fTotalCount(0), fLocalCount(0) {
+        fInitialRec.fNext = NULL;
+        fRec = &fInitialRec;
+
+    //  fCount = kSlotCount;
+    }
+
+    ~SkTDStackNester() {
+        Rec* rec = fRec;
+        while (rec != &fInitialRec) {
+            Rec* next = rec->fNext;
+            delete rec;
+            rec = next;
+        }
+    }
+
+    int count() const { return fLocalCount; }
+    bool empty() const { return fLocalCount == 0; }
+
+    int nests() {
+        return fNestingLevel;
+    }
+
+    void nest() {
+        // We are are past max nesting levels, we will still continue to work, but we might fail
+        // to properly ignore errors. Ideally it should only mean poor rendering in exceptional
+        // cases
+        if (fNestingLevel >= 0 && fNestingLevel < MAX_NESTING) {
+            fNestings[fNestingLevel] = fLocalCount;
+            fLocalCount = 0;
+        }
+        fNestingLevel++;
+    }
+
+    void unnest() {
+        SkASSERT(fNestingLevel > 0);
+        fNestingLevel--;
+        if (fNestingLevel >= 0 && fNestingLevel < MAX_NESTING) {
+            // TODO(edisonn): warn if fLocal > 0
+            while (fLocalCount > 0) {
+                pop();
+            }
+            fLocalCount = fNestings[fNestingLevel];
+        }
+    }
+
+    T* push() {
+        SkASSERT(fCount <= kSlotCount);
+        if (fCount == kSlotCount) {
+            Rec* rec = new Rec();
+            rec->fNext = fRec;
+            fRec = rec;
+            fCount = 0;
+        }
+        ++fTotalCount;
+        ++fLocalCount;
+        return &fRec->fSlots[fCount++];
+    }
+
+    void push(const T& elem) { *this->push() = elem; }
+
+    const T& index(int idx) const {
+        SkASSERT(fRec && fCount > idx);
+        return fRec->fSlots[fCount - idx - 1];
+    }
+
+    T& index(int idx) {
+        SkASSERT(fRec && fCount > idx);
+        return fRec->fSlots[fCount - idx - 1];
+    }
+
+    const T& top() const {
+        SkASSERT(fRec && fCount > 0);
+        return fRec->fSlots[fCount - 1];
+    }
+
+    T& top() {
+        SkASSERT(fRec && fCount > 0);
+        return fRec->fSlots[fCount - 1];
+    }
+
+    void pop(T* elem) {
+        if (elem) {
+            *elem = fRec->fSlots[fCount - 1];
+        }
+        this->pop();
+    }
+
+    void pop() {
+        SkASSERT(fCount > 0 && fRec);
+        --fLocalCount;
+        --fTotalCount;
+        if (--fCount == 0) {
+            if (fRec != &fInitialRec) {
+                Rec* rec = fRec->fNext;
+                delete fRec;
+                fCount = kSlotCount;
+                fRec = rec;
+            } else {
+                SkASSERT(fTotalCount == 0);
+            }
+        }
+    }
+
+private:
+    enum {
+        kSlotCount  = 64
+    };
+
+    struct Rec;
+    friend struct Rec;
+
+    struct Rec {
+        Rec* fNext;
+        T    fSlots[kSlotCount];
+    };
+    Rec     fInitialRec;
+    Rec*    fRec;
+    int     fCount, fTotalCount, fLocalCount;
+    int     fNestings[MAX_NESTING];
+    int     fNestingLevel;
+};
+#endif // SkTDStackNester_DEFINED