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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
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