/* -*- 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/. */

#include "nsSHEntryShared.h"

#include "nsArray.h"

#include "nsDocShellEditorData.h"

#include "nsIContentViewer.h"

#include "nsIDocShell.h"

#include "nsIDocShellTreeItem.h"

#include "nsIDocument.h"

#include "nsILayoutHistoryState.h"

#include "nsISHistory.h"

#include "nsIWebNavigation.h"

#include "nsThreadUtils.h"

#include "mozilla/Attributes.h"

#include "mozilla/Preferences.h"

namespace dom = mozilla::dom;

namespace {

uint64_t gSHEntrySharedID = 0;

} // namespace

void

nsSHEntryShared::Shutdown()

{

}

nsSHEntryShared::nsSHEntryShared()

  : mDocShellID({0})

  , mCacheKey(0)

  , mLastTouched(0)

  , mID(gSHEntrySharedID++)

  , mViewerBounds(0, 0, 0, 0)

  , mIsFrameNavigation(false)

  , mSaveLayoutState(true)

  , mSticky(true)

  , mDynamicallyCreated(false)

  , mExpired(false)

{

}

nsSHEntryShared::~nsSHEntryShared()

{

  // The destruction can be caused by either the entry is removed from session

  // history and no one holds the reference, or the whole session history is on

  // destruction. We want to ensure that we invoke

  // shistory->RemoveFromExpirationTracker for the former case.

  RemoveFromExpirationTracker();

  // Calling RemoveDynEntriesForBFCacheEntry on destruction is unnecessary since

  // there couldn't be any SHEntry holding this shared entry, and we noticed

  // that calling RemoveDynEntriesForBFCacheEntry in the middle of

  // nsSHistory::Release can cause a crash, so set mSHistory to null explicitly

  // before RemoveFromBFCacheSync.

  mSHistory = nullptr;

  if (mContentViewer) {

    RemoveFromBFCacheSync();

  }

}

NS_IMPL_ISUPPORTS(nsSHEntryShared, nsIBFCacheEntry, nsIMutationObserver)

already_AddRefed<nsSHEntryShared>

nsSHEntryShared::Duplicate(nsSHEntryShared* aEntry)

{

  RefPtr<nsSHEntryShared> newEntry = new nsSHEntryShared();

  newEntry->mDocShellID = aEntry->mDocShellID;

  newEntry->mChildShells.AppendObjects(aEntry->mChildShells);

  newEntry->mTriggeringPrincipal = aEntry->mTriggeringPrincipal;

  newEntry->mPrincipalToInherit = aEntry->mPrincipalToInherit;

  newEntry->mContentType.Assign(aEntry->mContentType);

  newEntry->mIsFrameNavigation = aEntry->mIsFrameNavigation;

  newEntry->mSaveLayoutState = aEntry->mSaveLayoutState;

  newEntry->mSticky = aEntry->mSticky;

  newEntry->mDynamicallyCreated = aEntry->mDynamicallyCreated;

  newEntry->mCacheKey = aEntry->mCacheKey;

  newEntry->mLastTouched = aEntry->mLastTouched;

  return newEntry.forget();

}

void

nsSHEntryShared::RemoveFromExpirationTracker()

{

  nsCOMPtr<nsISHistory> shistory = do_QueryReferent(mSHistory);

  if (shistory && GetExpirationState()->IsTracked()) {

    shistory->RemoveFromExpirationTracker(this);

  }

}

void

nsSHEntryShared::SyncPresentationState()

{

  if (mContentViewer && mWindowState) {

    // If we have a content viewer and a window state, we should be ok.

    return;

  }

  DropPresentationState();

}

void

nsSHEntryShared::DropPresentationState()

{

  RefPtr<nsSHEntryShared> kungFuDeathGrip = this;

  if (mDocument) {

    mDocument->SetBFCacheEntry(nullptr);

    mDocument->RemoveMutationObserver(this);

    mDocument = nullptr;

  }

  if (mContentViewer) {

    mContentViewer->ClearHistoryEntry();

  }

  RemoveFromExpirationTracker();

  mContentViewer = nullptr;

  mSticky = true;

  mWindowState = nullptr;

  mViewerBounds.SetRect(0, 0, 0, 0);

  mChildShells.Clear();

  mRefreshURIList = nullptr;

  mEditorData = nullptr;

}

nsresult

nsSHEntryShared::SetContentViewer(nsIContentViewer* aViewer)

{

  MOZ_ASSERT(!aViewer || !mContentViewer,

             "SHEntryShared already contains viewer");

  if (mContentViewer || !aViewer) {

    DropPresentationState();

  }

  // If we're setting mContentViewer to null, state should already be cleared

  // in the DropPresentationState() call above; If we're setting it to a

  // non-null content viewer, the entry shouldn't have been tracked either.

  MOZ_ASSERT(!GetExpirationState()->IsTracked());

  mContentViewer = aViewer;

  if (mContentViewer) {

    // mSHistory is only set for root entries, but in general bfcache only

    // applies to root entries as well. BFCache for subframe navigation has been

    // disabled since 2005 in bug 304860.

    if (nsCOMPtr<nsISHistory> shistory = do_QueryReferent(mSHistory)) {

      shistory->AddToExpirationTracker(this);

    }

    // Store observed document in strong pointer in case it is removed from

    // the contentviewer

    mDocument = mContentViewer->GetDocument();

    if (mDocument) {

      mDocument->SetBFCacheEntry(this);

      mDocument->AddMutationObserver(this);

    }

  }

  return NS_OK;

}

nsresult

nsSHEntryShared::RemoveFromBFCacheSync()

{

  MOZ_ASSERT(mContentViewer && mDocument, "we're not in the bfcache!");

  // The call to DropPresentationState could drop the last reference, so hold

  // |this| until RemoveDynEntriesForBFCacheEntry finishes.

  RefPtr<nsSHEntryShared> kungFuDeathGrip = this;

  // DropPresentationState would clear mContentViewer.

  nsCOMPtr<nsIContentViewer> viewer = mContentViewer;

  DropPresentationState();

  if (viewer) {

    viewer->Destroy();

  }

  // Now that we've dropped the viewer, we have to clear associated dynamic

  // subframe entries.

  nsCOMPtr<nsISHistory> shistory = do_QueryReferent(mSHistory);

  if (shistory) {

    shistory->RemoveDynEntriesForBFCacheEntry(this);

  }

  return NS_OK;

}

nsresult

nsSHEntryShared::RemoveFromBFCacheAsync()

{

  MOZ_ASSERT(mContentViewer && mDocument, "we're not in the bfcache!");

  // Check it again to play safe in release builds.

  if (!mDocument) {

    return NS_ERROR_UNEXPECTED;

  }

  // DropPresentationState would clear mContentViewer & mDocument. Capture and

  // release the references asynchronously so that the document doesn't get

  // nuked mid-mutation.

  nsCOMPtr<nsIContentViewer> viewer = mContentViewer;

  nsCOMPtr<nsIDocument> document = mDocument;

  RefPtr<nsSHEntryShared> self = this;

  nsresult rv = mDocument->Dispatch(mozilla::TaskCategory::Other,

    NS_NewRunnableFunction("nsSHEntryShared::RemoveFromBFCacheAsync",

    [self, viewer, document]() {

      if (viewer) {

        viewer->Destroy();

      }

      nsCOMPtr<nsISHistory> shistory = do_QueryReferent(self->mSHistory);

      if (shistory) {

        shistory->RemoveDynEntriesForBFCacheEntry(self);

      }

    }));

  if (NS_FAILED(rv)) {

    NS_WARNING("Failed to dispatch RemoveFromBFCacheAsync runnable.");

  } else {

    // Drop presentation. Only do this if we succeeded in posting the event

    // since otherwise the document could be torn down mid-mutation, causing

    // crashes.

    DropPresentationState();

  }

  return NS_OK;

}

nsresult

nsSHEntryShared::GetID(uint64_t* aID)

{

  *aID = mID;

  return NS_OK;

}

void

nsSHEntryShared::CharacterDataChanged(nsIContent* aContent,

                                      const CharacterDataChangeInfo&)

{

  RemoveFromBFCacheAsync();

}

void

nsSHEntryShared::AttributeChanged(dom::Element* aElement,

                                  int32_t aNameSpaceID,

                                  nsAtom* aAttribute,

                                  int32_t aModType,

                                  const nsAttrValue* aOldValue)

{

  RemoveFromBFCacheAsync();

}

void

nsSHEntryShared::ContentAppended(nsIContent* aFirstNewContent)

{

  RemoveFromBFCacheAsync();

}

void

nsSHEntryShared::ContentInserted(nsIContent* aChild)

{

  RemoveFromBFCacheAsync();

}

void

nsSHEntryShared::ContentRemoved(nsIContent* aChild,

                                nsIContent* aPreviousSibling)

{

  RemoveFromBFCacheAsync();

}