gecko-dev/dom/base/nsNodeInfoManager.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */

/*
 * A class for handing out nodeinfos and ensuring sharing of them as needed.
 */

#include "nsNodeInfoManager.h"

#include "mozilla/DebugOnly.h"
#include "mozilla/dom/NodeInfo.h"
#include "mozilla/dom/NodeInfoInlines.h"
#include "nsCOMPtr.h"
#include "nsString.h"
#include "nsAtom.h"
#include "nsIDocument.h"
#include "nsIPrincipal.h"
#include "nsIURI.h"
#include "nsContentUtils.h"
#include "nsReadableUtils.h"
#include "nsGkAtoms.h"
#include "nsComponentManagerUtils.h"
#include "nsLayoutStatics.h"
#include "nsBindingManager.h"
#include "nsHashKeys.h"
#include "nsCCUncollectableMarker.h"
#include "nsNameSpaceManager.h"
#include "nsDocument.h"
#include "nsWindowSizes.h"
#include "NullPrincipal.h"

using namespace mozilla;
using mozilla::dom::NodeInfo;

#include "mozilla/Logging.h"

static LazyLogModule gNodeInfoManagerLeakPRLog("NodeInfoManagerLeak");
static const uint32_t kInitialNodeInfoHashSize = 32;

nsNodeInfoManager::nsNodeInfoManager()
  : mNodeInfoHash(kInitialNodeInfoHashSize),
    mDocument(nullptr),
    mNonDocumentNodeInfos(0),
    mTextNodeInfo(nullptr),
    mCommentNodeInfo(nullptr),
    mDocumentNodeInfo(nullptr),
    mRecentlyUsedNodeInfos{},
    mSVGEnabled(eTriUnset),
    mMathMLEnabled(eTriUnset)
{
  nsLayoutStatics::AddRef();

  if (gNodeInfoManagerLeakPRLog)
    MOZ_LOG(gNodeInfoManagerLeakPRLog, LogLevel::Debug,
           ("NODEINFOMANAGER %p created", this));
}


nsNodeInfoManager::~nsNodeInfoManager()
{
  // Note: mPrincipal may be null here if we never got inited correctly
  mPrincipal = nullptr;

  mBindingManager = nullptr;

  if (gNodeInfoManagerLeakPRLog)
    MOZ_LOG(gNodeInfoManagerLeakPRLog, LogLevel::Debug,
           ("NODEINFOMANAGER %p destroyed", this));

  nsLayoutStatics::Release();
}

NS_IMPL_CYCLE_COLLECTION_CLASS(nsNodeInfoManager)

NS_IMPL_CYCLE_COLLECTION_UNLINK_0(nsNodeInfoManager)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsNodeInfoManager)
  if (tmp->mNonDocumentNodeInfos) {
    NS_IMPL_CYCLE_COLLECTION_TRAVERSE_RAWPTR(mDocument)
  }
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mBindingManager)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(nsNodeInfoManager, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(nsNodeInfoManager, Release)

NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(nsNodeInfoManager)
  if (tmp->mDocument) {
    return NS_CYCLE_COLLECTION_PARTICIPANT(nsDocument)->CanSkip(tmp->mDocument, aRemovingAllowed);
  }
NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_END

NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_BEGIN(nsNodeInfoManager)
  if (tmp->mDocument) {
    return NS_CYCLE_COLLECTION_PARTICIPANT(nsDocument)->CanSkipInCC(tmp->mDocument);
  }
NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_END

NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(nsNodeInfoManager)
  if (tmp->mDocument) {
    return NS_CYCLE_COLLECTION_PARTICIPANT(nsDocument)->CanSkipThis(tmp->mDocument);
  }
NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_END

nsresult
nsNodeInfoManager::Init(nsIDocument *aDocument)
{
  NS_PRECONDITION(!mPrincipal,
                  "Being inited when we already have a principal?");

  mPrincipal = NullPrincipal::CreateWithoutOriginAttributes();

  if (aDocument) {
    mBindingManager = new nsBindingManager(aDocument);
  }

  mDefaultPrincipal = mPrincipal;

  mDocument = aDocument;

  if (gNodeInfoManagerLeakPRLog)
    MOZ_LOG(gNodeInfoManagerLeakPRLog, LogLevel::Debug,
           ("NODEINFOMANAGER %p Init document=%p", this, aDocument));

  return NS_OK;
}

void
nsNodeInfoManager::DropDocumentReference()
{
  if (mBindingManager) {
    mBindingManager->DropDocumentReference();
  }

  // This is probably not needed anymore.
  for (auto iter = mNodeInfoHash.Iter(); !iter.Done(); iter.Next()) {
    iter.Data()->mDocument = nullptr;
  }

  NS_ASSERTION(!mNonDocumentNodeInfos, "Shouldn't have non-document nodeinfos!");
  mDocument = nullptr;
}


already_AddRefed<mozilla::dom::NodeInfo>
nsNodeInfoManager::GetNodeInfo(nsAtom *aName, nsAtom *aPrefix,
                               int32_t aNamespaceID, uint16_t aNodeType,
                               nsAtom* aExtraName /* = nullptr */)
{
  CheckValidNodeInfo(aNodeType, aName, aNamespaceID, aExtraName);

  NodeInfo::NodeInfoInner tmpKey(aName, aPrefix, aNamespaceID, aNodeType,
                                 aExtraName);

  uint32_t index = tmpKey.Hash() % RECENTLY_USED_NODEINFOS_SIZE;
  NodeInfo* ni = mRecentlyUsedNodeInfos[index];
  if (ni && tmpKey == ni->mInner) {
    RefPtr<NodeInfo> nodeInfo = ni;
    return nodeInfo.forget();
  }

  // We don't use LookupForAdd here as that would end up storing the temporary
  // key instead of using `mInner`.
  RefPtr<NodeInfo> nodeInfo = mNodeInfoHash.Get(&tmpKey);
  if (!nodeInfo) {
    ++mNonDocumentNodeInfos;
    if (mNonDocumentNodeInfos == 1) {
      NS_IF_ADDREF(mDocument);
    }

    nodeInfo = new NodeInfo(aName, aPrefix, aNamespaceID, aNodeType, aExtraName, this);
    mNodeInfoHash.Put(&nodeInfo->mInner, nodeInfo);
  }

  // Have to do the swap thing, because already_AddRefed<nsNodeInfo>
  // doesn't cast to already_AddRefed<mozilla::dom::NodeInfo>
  mRecentlyUsedNodeInfos[index] = nodeInfo;
  return nodeInfo.forget();
}


nsresult
nsNodeInfoManager::GetNodeInfo(const nsAString& aName, nsAtom *aPrefix,
                               int32_t aNamespaceID, uint16_t aNodeType,
                               NodeInfo** aNodeInfo)
{
  // TODO(erahm): Combine this with the atom version.
#ifdef DEBUG
  {
    RefPtr<nsAtom> nameAtom = NS_Atomize(aName);
    CheckValidNodeInfo(aNodeType, nameAtom, aNamespaceID, nullptr);
  }
#endif

  NodeInfo::NodeInfoInner tmpKey(aName, aPrefix, aNamespaceID, aNodeType);

  uint32_t index = tmpKey.Hash() % RECENTLY_USED_NODEINFOS_SIZE;
  NodeInfo* ni = mRecentlyUsedNodeInfos[index];
  if (ni && ni->mInner == tmpKey) {
    RefPtr<NodeInfo> nodeInfo = ni;
    nodeInfo.forget(aNodeInfo);
    return NS_OK;
  }

  RefPtr<NodeInfo> nodeInfo = mNodeInfoHash.Get(&tmpKey);
  if (!nodeInfo) {
    ++mNonDocumentNodeInfos;
    if (mNonDocumentNodeInfos == 1) {
      NS_IF_ADDREF(mDocument);
    }

    RefPtr<nsAtom> nameAtom = NS_Atomize(aName);
    nodeInfo = new NodeInfo(nameAtom, aPrefix, aNamespaceID, aNodeType, nullptr, this);
    mNodeInfoHash.Put(&nodeInfo->mInner, nodeInfo);
  }

  mRecentlyUsedNodeInfos[index] = nodeInfo;
  nodeInfo.forget(aNodeInfo);

  return NS_OK;
}


nsresult
nsNodeInfoManager::GetNodeInfo(const nsAString& aName, nsAtom *aPrefix,
                               const nsAString& aNamespaceURI,
                               uint16_t aNodeType,
                               NodeInfo** aNodeInfo)
{
  int32_t nsid = kNameSpaceID_None;

  if (!aNamespaceURI.IsEmpty()) {
    nsresult rv = nsContentUtils::NameSpaceManager()->
      RegisterNameSpace(aNamespaceURI, nsid);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return GetNodeInfo(aName, aPrefix, nsid, aNodeType, aNodeInfo);
}

already_AddRefed<NodeInfo>
nsNodeInfoManager::GetTextNodeInfo()
{
  RefPtr<mozilla::dom::NodeInfo> nodeInfo;

  if (!mTextNodeInfo) {
    nodeInfo = GetNodeInfo(nsGkAtoms::textTagName, nullptr, kNameSpaceID_None,
                           nsINode::TEXT_NODE, nullptr);
    // Hold a weak ref; the nodeinfo will let us know when it goes away
    mTextNodeInfo = nodeInfo;
  } else {
    nodeInfo = mTextNodeInfo;
  }

  return nodeInfo.forget();
}

already_AddRefed<NodeInfo>
nsNodeInfoManager::GetCommentNodeInfo()
{
  RefPtr<NodeInfo> nodeInfo;

  if (!mCommentNodeInfo) {
    nodeInfo = GetNodeInfo(nsGkAtoms::commentTagName, nullptr,
                           kNameSpaceID_None, nsINode::COMMENT_NODE,
                           nullptr);
    // Hold a weak ref; the nodeinfo will let us know when it goes away
    mCommentNodeInfo = nodeInfo;
  }
  else {
    nodeInfo = mCommentNodeInfo;
  }

  return nodeInfo.forget();
}

already_AddRefed<NodeInfo>
nsNodeInfoManager::GetDocumentNodeInfo()
{
  RefPtr<NodeInfo> nodeInfo;

  if (!mDocumentNodeInfo) {
    NS_ASSERTION(mDocument, "Should have mDocument!");
    nodeInfo = GetNodeInfo(nsGkAtoms::documentNodeName, nullptr,
                           kNameSpaceID_None, nsINode::DOCUMENT_NODE,
                           nullptr);
    // Hold a weak ref; the nodeinfo will let us know when it goes away
    mDocumentNodeInfo = nodeInfo;

    --mNonDocumentNodeInfos;
    if (!mNonDocumentNodeInfos) {
      mDocument->Release(); // Don't set mDocument to null!
    }
  }
  else {
    nodeInfo = mDocumentNodeInfo;
  }

  return nodeInfo.forget();
}

void
nsNodeInfoManager::SetDocumentPrincipal(nsIPrincipal *aPrincipal)
{
  mPrincipal = nullptr;
  if (!aPrincipal) {
    aPrincipal = mDefaultPrincipal;
  }

  NS_ASSERTION(aPrincipal, "Must have principal by this point!");
  MOZ_DIAGNOSTIC_ASSERT(!nsContentUtils::IsExpandedPrincipal(aPrincipal),
                        "Documents shouldn't have an expanded principal");

  mPrincipal = aPrincipal;
}

void
nsNodeInfoManager::RemoveNodeInfo(NodeInfo *aNodeInfo)
{
  NS_PRECONDITION(aNodeInfo, "Trying to remove null nodeinfo from manager!");

  if (aNodeInfo == mDocumentNodeInfo) {
    mDocumentNodeInfo = nullptr;
    mDocument = nullptr;
  } else {
    if (--mNonDocumentNodeInfos == 0) {
      if (mDocument) {
        // Note, whoever calls this method should keep NodeInfoManager alive,
        // even if mDocument gets deleted.
        mDocument->Release();
      }
    }
    // Drop weak reference if needed
    if (aNodeInfo == mTextNodeInfo) {
      mTextNodeInfo = nullptr;
    }
    else if (aNodeInfo == mCommentNodeInfo) {
      mCommentNodeInfo = nullptr;
    }
  }

  uint32_t index = aNodeInfo->mInner.Hash() % RECENTLY_USED_NODEINFOS_SIZE;
  if (mRecentlyUsedNodeInfos[index] == aNodeInfo) {
    mRecentlyUsedNodeInfos[index] = nullptr;
  }

  DebugOnly<bool> ret = mNodeInfoHash.Remove(&aNodeInfo->mInner);
  MOZ_ASSERT(ret, "Can't find mozilla::dom::NodeInfo to remove!!!");
}

bool
nsNodeInfoManager::InternalSVGEnabled()
{
  // If the svg.disabled pref. is true, convert all SVG nodes into
  // disabled SVG nodes by swapping the namespace.
  nsNameSpaceManager* nsmgr = nsNameSpaceManager::GetInstance();
  nsCOMPtr<nsILoadInfo> loadInfo;
  bool SVGEnabled = false;

  if (nsmgr && !nsmgr->mSVGDisabled) {
    SVGEnabled = true;
  } else {
    nsCOMPtr<nsIChannel> channel = mDocument->GetChannel();
    // We don't have a channel for SVGs constructed inside a SVG script
    if (channel) {
      loadInfo = channel->GetLoadInfo();
    }
  }
  bool conclusion =
    (SVGEnabled || nsContentUtils::IsSystemPrincipal(mPrincipal) ||
     (loadInfo &&
      (loadInfo->GetExternalContentPolicyType() ==
         nsIContentPolicy::TYPE_IMAGE ||
       loadInfo->GetExternalContentPolicyType() ==
         nsIContentPolicy::TYPE_OTHER) &&
      (nsContentUtils::IsSystemPrincipal(loadInfo->LoadingPrincipal()) ||
       nsContentUtils::IsSystemPrincipal(loadInfo->TriggeringPrincipal()))));
  mSVGEnabled = conclusion ? eTriTrue : eTriFalse;
  return conclusion;
}

bool
nsNodeInfoManager::InternalMathMLEnabled()
{
  // If the mathml.disabled pref. is true, convert all MathML nodes into
  // disabled MathML nodes by swapping the namespace.
  nsNameSpaceManager* nsmgr = nsNameSpaceManager::GetInstance();
  bool conclusion = ((nsmgr && !nsmgr->mMathMLDisabled) ||
                     nsContentUtils::IsSystemPrincipal(mPrincipal));
  mMathMLEnabled = conclusion ? eTriTrue : eTriFalse;
  return conclusion;
}

void
nsNodeInfoManager::AddSizeOfIncludingThis(nsWindowSizes& aSizes) const
{
  aSizes.mDOMOtherSize += aSizes.mState.mMallocSizeOf(this);

  if (mBindingManager) {
    aSizes.mBindingsSize +=
      mBindingManager->SizeOfIncludingThis(aSizes.mState.mMallocSizeOf);
  }

  // Measurement of the following members may be added later if DMD finds it
  // is worthwhile:
  // - mNodeInfoHash
}