Unwind PDFObject destructor calls into heap instead of stack. Notice: the order of the destructors …

src/pdf/SkPDFTypes.h

Index: src/pdf/SkPDFTypes.h
===================================================================
--- src/pdf/SkPDFTypes.h	(revision 8010)
+++ src/pdf/SkPDFTypes.h	(working copy)
@@ -29,6 +29,8 @@
 public:
     SK_DECLARE_INST_COUNT(SkPDFObject)
 
+    virtual ~SkPDFObject() { };
+
     /** Return the size (number of bytes) of this object in the final output
      *  file. Compound objects or objects that are computationally intensive
      *  to output should override this method.
@@ -79,6 +81,25 @@
     static void GetResourcesHelper(SkTDArray<SkPDFObject*>* resources,
                                    SkTDArray<SkPDFObject*>* result);
 
+    /** Destroys safely an array of SkPDFObjects.
+     *  The stack won't be used much, and stack overflow will be avoided.
+     */
+    static void safeUnref(SkTDArray<SkPDFObject*>* list) {
+        while (list->count() > 0) {
+            SkPDFObject* obj = NULL;
+            list->pop(&obj);
+            if (obj) {
+                // Releases all refs to be owned by list, unref will call destructor!
+                if (obj->getRefCnt() == 1) {
+                    obj->transferPDFObjectsOwnership(list);
+                }
+                // If unref calls destructor, it won't call recursively
+                // other ~SkPDFObjects().
+                obj->unref();
+            }
+        }
+    }
+
 protected:
     /** Subclasses must implement this method to print the object to the
      *  PDF file.
@@ -89,6 +110,13 @@
     virtual void emitObject(SkWStream* stream, SkPDFCatalog* catalog,
                             bool indirect) = 0;
 
+    /** Dumps all the SkPDFObject members in the list. When the destructor is
+     *  called, the stack won't be used much.
+     *  This method will destroy the state of the object. Should be called only
+     *  during destructor calls.
+     */
+    virtual void transferPDFObjectsOwnership(SkTDArray<SkPDFObject*>* list) {}
+
         typedef SkRefCnt INHERITED;
 };
 
@@ -111,6 +139,13 @@
                             bool indirect);
     virtual size_t getOutputSize(SkPDFCatalog* catalog, bool indirect);
 
+protected:
+    virtual void transferPDFObjectsOwnership(SkTDArray<SkPDFObject*>* list) {
+        list->push(fObj.detach());
+
+        INHERITED::transferPDFObjectsOwnership(list);
+    }
+
 private:
     SkAutoTUnref<SkPDFObject> fObj;
 
@@ -406,6 +441,18 @@
      */
     void clear();
 
+    virtual void transferPDFObjectsOwnership(SkTDArray<SkPDFObject*>* list) {
+        for (int i = 0; i < fValue.count(); i++) {
+            list->push(fValue[i].key);
+            fValue[i].key = NULL;
+            list->push(fValue[i].value);
+            fValue[i].value = NULL;
+        }
+        fValue.reset();
+
+        INHERITED::transferPDFObjectsOwnership(list);
+    }
+
 private:
     struct Rec {
       SkPDFName* key;