Bug 1024774 - Part 11: Implement a JS::ubi::Node specialization for DeserializedNode; r=jimb

js/public/UbiNode.h

@@ -187,6 +187,21 @@ class Base {
     }
     bool operator!=(const Base& rhs) const { return !(*this == rhs); }
 
+    // An identifier for this node, guaranteed to be stable and unique for as
+    // long as this ubi::Node's referent is alive and at the same address.
+    //
+    // This is probably suitable for use in serializations, as it is an integral
+    // type. It may also help save memory when constructing HashSets of
+    // ubi::Nodes: since a uintptr_t will always be smaller than a ubi::Node, a
+    // HashSet<ubi::Node::Id> will use less space per element than a
+    // HashSet<ubi::Node>.
+    //
+    // (Note that 'unique' only means 'up to equality on ubi::Node'; see the
+    // caveats about multiple objects allocated at the same address for
+    // 'ubi::Node::operator=='.)
+    typedef uintptr_t Id;
+    virtual Id identifier() const { return reinterpret_cast<Id>(ptr); }
+
     // Returns true if this node is pointing to something on the live heap, as
     // opposed to something from a deserialized core dump. Returns false,
     // otherwise.
@@ -385,20 +400,8 @@ class Node {
         return base()->edges(cx, wantNames);
     }
 
-    // An identifier for this node, guaranteed to be stable and unique for as
-    // long as this ubi::Node's referent is alive and at the same address.
-    //
-    // This is probably suitable for use in serializations, as it is an integral
-    // type. It may also help save memory when constructing HashSets of
-    // ubi::Nodes: since a uintptr_t will always be smaller than a ubi::Node, a
-    // HashSet<ubi::Node::Id> will use less space per element than a
-    // HashSet<ubi::Node>.
-    //
-    // (Note that 'unique' only means 'up to equality on ubi::Node'; see the
-    // caveats about multiple objects allocated at the same address for
-    // 'ubi::Node::operator=='.)
-    typedef uintptr_t Id;
-    Id identifier() const { return reinterpret_cast<Id>(base()->ptr); }
+    typedef Base::Id Id;
+    Id identifier() const { return base()->identifier(); }
 
     // A hash policy for ubi::Nodes.
     // This simply uses the stock PointerHasher on the ubi::Node's pointer.

toolkit/devtools/server/DeserializedNode.cpp

@@ -4,6 +4,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/devtools/DeserializedNode.h"
+#include "mozilla/devtools/HeapSnapshot.h"
+#include "nsCRTGlue.h"
 
 namespace mozilla {
 namespace devtools {
@@ -107,3 +109,86 @@ DeserializedNode::getEdgeReferent(const DeserializedEdge &edge)
 
 } // namespace devtools
 } // namespace mozilla
+
+namespace JS {
+namespace ubi {
+
+using mozilla::devtools::DeserializedEdge;
+
+const char16_t Concrete<DeserializedNode>::concreteTypeName[] =
+  MOZ_UTF16("mozilla::devtools::DeserializedNode");
+
+const char16_t *
+Concrete<DeserializedNode>::typeName() const
+{
+  return get().typeName;
+}
+
+size_t
+Concrete<DeserializedNode>::size(mozilla::MallocSizeOf mallocSizeof) const
+{
+  return get().size;
+}
+
+class DeserializedEdgeRange : public EdgeRange
+{
+  SimpleEdgeVector edges;
+  size_t           i;
+
+  void settle() {
+    front_ = i < edges.length() ? &edges[i] : nullptr;
+  }
+
+public:
+  explicit DeserializedEdgeRange(JSContext* cx)
+    : edges(cx)
+    , i(0)
+  {
+    settle();
+  }
+
+  bool init(DeserializedNode &node)
+  {
+    if (!edges.reserve(node.edges.length()))
+      return false;
+
+    for (DeserializedEdge *edgep = node.edges.begin();
+         edgep != node.edges.end();
+         edgep++)
+    {
+      char16_t *name = nullptr;
+      if (edgep->name) {
+        name = NS_strdup(edgep->name);
+        if (!name)
+          return false;
+      }
+
+      DeserializedNode &referent = node.getEdgeReferent(*edgep);
+      edges.infallibleAppend(mozilla::Move(SimpleEdge(name, Node(&referent))));
+    }
+
+    settle();
+    return true;
+  }
+
+  void popFront() override
+  {
+    i++;
+    settle();
+  }
+};
+
+UniquePtr<EdgeRange>
+Concrete<DeserializedNode>::edges(JSContext* cx, bool) const
+{
+  UniquePtr<DeserializedEdgeRange, JS::DeletePolicy<DeserializedEdgeRange>> range(
+    js_new<DeserializedEdgeRange>(cx));
+
+  if (!range || !range->init(get()))
+    return nullptr;
+
+  return UniquePtr<EdgeRange>(range.release());
+}
+
+} // namespace JS
+} // namespace ubi

toolkit/devtools/server/DeserializedNode.h

@@ -6,6 +6,7 @@
 #ifndef mozilla_devtools_DeserializedNode__
 #define mozilla_devtools_DeserializedNode__
 
+#include "js/UbiNode.h"
 #include "mozilla/devtools/CoreDump.pb.h"
 #include "mozilla/MaybeOneOf.h"
 #include "mozilla/Move.h"
@@ -88,4 +89,39 @@ private:
 } // namespace devtools
 } // namespace mozilla
 
+namespace JS {
+namespace ubi {
+
+using mozilla::devtools::DeserializedNode;
+using mozilla::UniquePtr;
+
+template<>
+struct Concrete<DeserializedNode> : public Base
+{
+protected:
+  explicit Concrete(DeserializedNode *ptr) : Base(ptr) { }
+  DeserializedNode &get() const {
+    return *static_cast<DeserializedNode *>(ptr);
+  }
+
+public:
+  static const char16_t concreteTypeName[];
+
+  static void construct(void *storage, DeserializedNode *ptr) {
+    new (storage) Concrete(ptr);
+  }
+
+  Id identifier() const override { return get().id; }
+  bool isLive() const override { return false; }
+  const char16_t *typeName() const override;
+  size_t size(mozilla::MallocSizeOf mallocSizeof) const override;
+
+  // We ignore the `bool wantNames` parameter because we can't control whether
+  // the core dump was serialized with edge names or not.
+  UniquePtr<EdgeRange> edges(JSContext* cx, bool) const override;
+};
+
+} // namespace JS
+} // namespace ubi
+
 #endif // mozilla_devtools_DeserializedNode__