Closed Bug 1545474 Opened 2 years ago Closed 2 years ago

Change nsSHistory::EvictContentViewerForEntry to accommodate session history changes


(Core :: DOM: Navigation, task, P2)

Other Branch



Fission Milestone M4


(Reporter: annyG, Assigned: annyG)


(Blocks 1 open bug)



(3 files)

No description provided.
Depends on: 1438272
Fission Milestone: --- → M3
Priority: -- → P2

Inside of nsDocShell::UpdateURLAndHistory, there are 4 sync IPC calls to
nsSHistory plus 1 static call, which contains at least one nsSHEntry::GetParent
sync IPC call. All of these calls can be moved inside of a new method
EvictContentViewersOrReplaceEntry on nsSHEntry, resulting in just 1 sync IPC

When we need to evict content viewers, we group SHEntrySharedParentState,
corresponding to session history entries that need to be evicted, by their
content parent, and create a runnable for each content parent. In the runnable
we use the passed in IDs of SHEntrySharedParentStates to retrieve corresponding content
viewers and evict them.

Depends on D32729

Add a new method to session history listener to listen for content
viewers being evicted.

Depends on D32730

Peter, here I will explain the rationale behind adding method NotifyListenersContentViewerEvicted to SHEntryChildShared and SHEntrySharedParentState. But first, a backstory!

Whenever NotifyListenersContentViewerEvicted is defined on nsSHistory or SHistoryChild, it actually uses the NOTIFY_LISTENERS macro and informs mListeners about an event. I have added NotifyListenersContentViewerEvicted() in nsISHistory.idl because nsSHistory and SHistoryChild both have their own listeners. Then I added calls to NotifyListenersContentViewerEvicted() in nsSHistory::EvictContentViewerForEntry and SHistoryChild::NotifyListenersContentViewerEvicted because these two places evict content viewers.

There are several other places where a content viewer gets evicted

  • SHEntryChildShared::EvictContentViewers()
  • nsSHEntry::EvictContentViewer()
  • SHEntryChild::EvictContentViewer()

We don't have access to session history from those places to call nsISHistory::NotifyListenersContentViewerEvicted, however, we do have access to mShared, the type of which is SHEntryChildShared or SHEntrySHaredParentState, both of which have local mSHistory. Thus, we want to define a method on SHEntryChildShared and SHEntrySHaredParentState that will invoke NotifyListenersContentViewerEvicted() on the session history. The solution is to define a method NotifyListenersContentViewerEvicted which will use local mSHistory and call nsISHistory::NotifyListenersContentViewerEvicted on it.

Fission Milestone: M3 → M4
Type: enhancement → task
Depends on: 1560940
Duplicate of this bug: 1546762
Regressions: 1591899
Pushed by
Part 1: Consolidate sync IPC calls inside of nsDocShell::UpdateURLAndHistory, r=peterv, r=nika for adding sync IPC messages
Part 2: Modify eviction of content viewers to accomodate session history changes, r=peterv
Part 3: Test eviction of content viewer entries, r=peterv
Regressions: 1594390
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