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-rw-r--r--dom/heapsnapshot/DominatorTree.cpp140
1 files changed, 140 insertions, 0 deletions
diff --git a/dom/heapsnapshot/DominatorTree.cpp b/dom/heapsnapshot/DominatorTree.cpp
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index 000000000..e53c196cf
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+++ b/dom/heapsnapshot/DominatorTree.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
+/* 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/. */
+
+#include "mozilla/devtools/DominatorTree.h"
+#include "mozilla/dom/DominatorTreeBinding.h"
+
+namespace mozilla {
+namespace devtools {
+
+dom::Nullable<uint64_t>
+DominatorTree::GetRetainedSize(uint64_t aNodeId, ErrorResult& aRv)
+{
+ JS::ubi::Node::Id id(aNodeId);
+ auto node = mHeapSnapshot->getNodeById(id);
+ if (node.isNothing())
+ return dom::Nullable<uint64_t>();
+
+ auto mallocSizeOf = GetCurrentThreadDebuggerMallocSizeOf();
+ JS::ubi::Node::Size size = 0;
+ if (!mDominatorTree.getRetainedSize(*node, mallocSizeOf, size)) {
+ aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+ return dom::Nullable<uint64_t>();
+ }
+
+ MOZ_ASSERT(size != 0,
+ "The node should not have been unknown since we got it from the heap snapshot.");
+ return dom::Nullable<uint64_t>(size);
+}
+
+struct NodeAndRetainedSize
+{
+ JS::ubi::Node mNode;
+ JS::ubi::Node::Size mSize;
+
+ NodeAndRetainedSize(const JS::ubi::Node& aNode, JS::ubi::Node::Size aSize)
+ : mNode(aNode)
+ , mSize(aSize)
+ { }
+
+ struct Comparator
+ {
+ static bool
+ Equals(const NodeAndRetainedSize& aLhs, const NodeAndRetainedSize& aRhs)
+ {
+ return aLhs.mSize == aRhs.mSize;
+ }
+
+ static bool
+ LessThan(const NodeAndRetainedSize& aLhs, const NodeAndRetainedSize& aRhs)
+ {
+ // Use > because we want to sort from greatest to least retained size.
+ return aLhs.mSize > aRhs.mSize;
+ }
+ };
+};
+
+void
+DominatorTree::GetImmediatelyDominated(uint64_t aNodeId,
+ dom::Nullable<nsTArray<uint64_t>>& aOutResult,
+ ErrorResult& aRv)
+{
+ MOZ_ASSERT(aOutResult.IsNull());
+
+ JS::ubi::Node::Id id(aNodeId);
+ Maybe<JS::ubi::Node> node = mHeapSnapshot->getNodeById(id);
+ if (node.isNothing())
+ return;
+
+ // Get all immediately dominated nodes and their retained sizes.
+ MallocSizeOf mallocSizeOf = GetCurrentThreadDebuggerMallocSizeOf();
+ Maybe<JS::ubi::DominatorTree::DominatedSetRange> range = mDominatorTree.getDominatedSet(*node);
+ MOZ_ASSERT(range.isSome(), "The node should be known, since we got it from the heap snapshot.");
+ size_t length = range->length();
+ nsTArray<NodeAndRetainedSize> dominatedNodes(length);
+ for (const JS::ubi::Node& dominatedNode : *range) {
+ JS::ubi::Node::Size retainedSize = 0;
+ if (NS_WARN_IF(!mDominatorTree.getRetainedSize(dominatedNode, mallocSizeOf, retainedSize))) {
+ aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+ return;
+ }
+ MOZ_ASSERT(retainedSize != 0,
+ "retainedSize should not be zero since we know the node is in the dominator tree.");
+
+ dominatedNodes.AppendElement(NodeAndRetainedSize(dominatedNode, retainedSize));
+ }
+
+ // Sort them by retained size.
+ NodeAndRetainedSize::Comparator comparator;
+ dominatedNodes.Sort(comparator);
+
+ // Fill the result with the nodes' ids.
+ JS::ubi::Node root = mDominatorTree.root();
+ aOutResult.SetValue(nsTArray<uint64_t>(length));
+ for (const NodeAndRetainedSize& entry : dominatedNodes) {
+ // The root dominates itself, but we don't want to expose that to JS.
+ if (entry.mNode == root)
+ continue;
+
+ aOutResult.Value().AppendElement(entry.mNode.identifier());
+ }
+}
+
+dom::Nullable<uint64_t>
+DominatorTree::GetImmediateDominator(uint64_t aNodeId) const
+{
+ JS::ubi::Node::Id id(aNodeId);
+ Maybe<JS::ubi::Node> node = mHeapSnapshot->getNodeById(id);
+ if (node.isNothing())
+ return dom::Nullable<uint64_t>();
+
+ JS::ubi::Node dominator = mDominatorTree.getImmediateDominator(*node);
+ if (!dominator || dominator == *node)
+ return dom::Nullable<uint64_t>();
+
+ return dom::Nullable<uint64_t>(dominator.identifier());
+}
+
+
+/*** Cycle Collection Boilerplate *****************************************************************/
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DominatorTree, mParent, mHeapSnapshot)
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(DominatorTree)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(DominatorTree)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DominatorTree)
+ NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+ NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+/* virtual */ JSObject*
+DominatorTree::WrapObject(JSContext* aCx, JS::HandleObject aGivenProto)
+{
+ return dom::DominatorTreeBinding::Wrap(aCx, this, aGivenProto);
+}
+
+} // namespace devtools
+} // namespace mozilla