1 files changed, 106 insertions, 0 deletions
diff --git a/js/src/jspropertytree.h b/js/src/jspropertytree.h
new file mode 100644
index 000000000..b2544d496
--- /dev/null
+++ b/js/src/jspropertytree.h
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef jspropertytree_h
+#define jspropertytree_h
+
+#include "jsalloc.h"
+#include "jspubtd.h"
+
+#include "js/HashTable.h"
+
+namespace js {
+
+class Shape;
+struct StackShape;
+
+struct ShapeHasher : public DefaultHasher<Shape*> {
+    typedef Shape* Key;
+    typedef StackShape Lookup;
+
+    static inline HashNumber hash(const Lookup& l);
+    static inline bool match(Key k, const Lookup& l);
+};
+
+typedef HashSet<Shape*, ShapeHasher, SystemAllocPolicy> KidsHash;
+
+class KidsPointer {
+  private:
+    enum {
+        SHAPE = 0,
+        HASH  = 1,
+        TAG   = 1
+    };
+
+    uintptr_t w;
+
+  public:
+    bool isNull() const { return !w; }
+    void setNull() { w = 0; }
+
+    bool isShape() const { return (w & TAG) == SHAPE && !isNull(); }
+    Shape* toShape() const {
+        MOZ_ASSERT(isShape());
+        return reinterpret_cast<Shape*>(w & ~uintptr_t(TAG));
+    }
+    void setShape(Shape* shape) {
+        MOZ_ASSERT(shape);
+        MOZ_ASSERT((reinterpret_cast<uintptr_t>(static_cast<Shape*>(shape)) & TAG) == 0);
+        w = reinterpret_cast<uintptr_t>(static_cast<Shape*>(shape)) | SHAPE;
+    }
+
+    bool isHash() const { return (w & TAG) == HASH; }
+    KidsHash* toHash() const {
+        MOZ_ASSERT(isHash());
+        return reinterpret_cast<KidsHash*>(w & ~uintptr_t(TAG));
+    }
+    void setHash(KidsHash* hash) {
+        MOZ_ASSERT(hash);
+        MOZ_ASSERT((reinterpret_cast<uintptr_t>(hash) & TAG) == 0);
+        w = reinterpret_cast<uintptr_t>(hash) | HASH;
+    }
+
+#ifdef DEBUG
+    void checkConsistency(Shape* aKid) const;
+#endif
+};
+
+class PropertyTree
+{
+    friend class ::JSFunction;
+
+#ifdef DEBUG
+    JS::Zone* zone_;
+#endif
+
+    bool insertChild(ExclusiveContext* cx, Shape* parent, Shape* child);
+
+    PropertyTree();
+
+  public:
+    /*
+     * Use a lower limit for objects that are accessed using SETELEM (o[x] = y).
+     * These objects are likely used as hashmaps and dictionary mode is more
+     * efficient in this case.
+     */
+    enum {
+        MAX_HEIGHT = 512,
+        MAX_HEIGHT_WITH_ELEMENTS_ACCESS = 128
+    };
+
+    explicit PropertyTree(JS::Zone* zone)
+#ifdef DEBUG
+      : zone_(zone)
+#endif
+    {
+    }
+
+    Shape* getChild(ExclusiveContext* cx, Shape* parent, JS::Handle<StackShape> child);
+};
+
+} /* namespace js */
+
+#endif /* jspropertytree_h */