Bug 1347823 - Part 2: Move HistoryTracker to nsSHistory and bind its event target to the TabGroup. r=smaug

Convert the singleton HistoryTracker implementation to a per-nsSHistory based
implementation so that it can be bound to a TabGroup.

MozReview-Commit-ID: 7cMtArsO5lQ

--HG--
extra : rebase_source : 3711bc7f7afaa40772035e24270d4fde1d17924a

docshell/shistory/nsISHEntry.idl

@@ -21,6 +21,7 @@ interface nsIDocShellTreeItem;
 interface nsIStructuredCloneContainer;
 interface nsIBFCacheEntry;
 interface nsIPrincipal;
+interface nsISHistory;
 
 %{C++
 #include "nsRect.h"
@@ -326,6 +327,11 @@ interface nsISHEntry : nsISupports
      * if true == "manual", false == "auto".
      */
     attribute boolean scrollRestorationIsManual;
+
+    /**
+     * Set the session history it belongs to. It's only set on root entries.
+     */
+    [noscript] void setSHistory(in nsISHistory aSHistory);
 };
 
 [scriptable, uuid(bb66ac35-253b-471f-a317-3ece940f04c5)]

docshell/shistory/nsISHistoryInternal.idl

@@ -96,6 +96,16 @@ interface nsISHistoryInternal: nsISupports
     */
    void evictAllContentViewers();
 
+   /**
+    * Add a BFCache entry to expiration tracker so it gets evicted on expiration.
+    */
+   void addToExpirationTracker(in nsIBFCacheEntry aEntry);
+
+   /**
+    * Remove a BFCache entry from expiration tracker.
+    */
+   void removeFromExpirationTracker(in nsIBFCacheEntry aEntry);
+
    /**
     * Remove dynamic entries found at given index.
     *

docshell/shistory/nsSHEntry.cpp

@@ -962,3 +962,10 @@ nsSHEntry::SetLastTouched(uint32_t aLastTouched)
   mShared->mLastTouched = aLastTouched;
   return NS_OK;
 }
+
+NS_IMETHODIMP
+nsSHEntry::SetSHistory(nsISHistory* aSHistory)
+{
+  mShared->mSHistory = do_GetWeakReference(aSHistory);
+  return NS_OK;
+}

docshell/shistory/nsSHEntryShared.cpp

@@ -30,46 +30,9 @@ uint64_t gSHEntrySharedID = 0;
 
 } // namespace
 
-#define CONTENT_VIEWER_TIMEOUT_SECONDS "browser.sessionhistory.contentViewerTimeout"
-// Default this to time out unused content viewers after 30 minutes
-#define CONTENT_VIEWER_TIMEOUT_SECONDS_DEFAULT (30 * 60)
-
-typedef nsExpirationTracker<nsSHEntryShared, 3> HistoryTrackerBase;
-class HistoryTracker final : public HistoryTrackerBase
-{
-public:
-  explicit HistoryTracker(uint32_t aTimeout)
-    : HistoryTrackerBase(1000 * aTimeout / 2, "HistoryTracker")
-  {
-  }
-
-protected:
-  virtual void NotifyExpired(nsSHEntryShared* aObj)
-  {
-    RemoveObject(aObj);
-    aObj->Expire();
-  }
-};
-
-static HistoryTracker* gHistoryTracker = nullptr;
-
-void
-nsSHEntryShared::EnsureHistoryTracker()
-{
-  if (!gHistoryTracker) {
-    // nsExpirationTracker doesn't allow one to change the timer period,
-    // so just set it once when the history tracker is used for the first time.
-    gHistoryTracker = new HistoryTracker(
-      mozilla::Preferences::GetUint(CONTENT_VIEWER_TIMEOUT_SECONDS,
-                                    CONTENT_VIEWER_TIMEOUT_SECONDS_DEFAULT));
-  }
-}
-
 void
 nsSHEntryShared::Shutdown()
 {
-  delete gHistoryTracker;
-  gHistoryTracker = nullptr;
 }
 
 nsSHEntryShared::nsSHEntryShared()
@@ -88,20 +51,6 @@ nsSHEntryShared::nsSHEntryShared()
 nsSHEntryShared::~nsSHEntryShared()
 {
   RemoveFromExpirationTracker();
-
-#ifdef DEBUG
-  if (gHistoryTracker) {
-    // Check that we're not still on track to expire.  We shouldn't be, because
-    // we just removed ourselves!
-    nsExpirationTracker<nsSHEntryShared, 3>::Iterator iterator(gHistoryTracker);
-
-    nsSHEntryShared* elem;
-    while ((elem = iterator.Next()) != nullptr) {
-      NS_ASSERTION(elem != this, "Found dead entry still in the tracker!");
-    }
-  }
-#endif
-
   if (mContentViewer) {
     RemoveFromBFCacheSync();
   }
@@ -132,8 +81,9 @@ nsSHEntryShared::Duplicate(nsSHEntryShared* aEntry)
 void
 nsSHEntryShared::RemoveFromExpirationTracker()
 {
-  if (gHistoryTracker && GetExpirationState()->IsTracked()) {
-    gHistoryTracker->RemoveObject(this);
+  nsCOMPtr<nsISHistoryInternal> shistory = do_QueryReferent(mSHistory);
+  if (shistory && GetExpirationState()->IsTracked()) {
+    shistory->RemoveFromExpirationTracker(this);
   }
 }
 
@@ -174,34 +124,6 @@ nsSHEntryShared::DropPresentationState()
   mEditorData = nullptr;
 }
 
-void
-nsSHEntryShared::Expire()
-{
-  // This entry has timed out. If we still have a content viewer, we need to
-  // evict it.
-  if (!mContentViewer) {
-    return;
-  }
-  nsCOMPtr<nsIDocShell> container;
-  mContentViewer->GetContainer(getter_AddRefs(container));
-  nsCOMPtr<nsIDocShellTreeItem> treeItem = do_QueryInterface(container);
-  if (!treeItem) {
-    return;
-  }
-  // We need to find the root DocShell since only that object has an
-  // SHistory and we need the SHistory to evict content viewers
-  nsCOMPtr<nsIDocShellTreeItem> root;
-  treeItem->GetSameTypeRootTreeItem(getter_AddRefs(root));
-  nsCOMPtr<nsIWebNavigation> webNav = do_QueryInterface(root);
-  nsCOMPtr<nsISHistory> history;
-  webNav->GetSessionHistory(getter_AddRefs(history));
-  nsCOMPtr<nsISHistoryInternal> historyInt = do_QueryInterface(history);
-  if (!historyInt) {
-    return;
-  }
-  historyInt->EvictExpiredContentViewerForEntry(this);
-}
-
 nsresult
 nsSHEntryShared::SetContentViewer(nsIContentViewer* aViewer)
 {
@@ -215,8 +137,13 @@ nsSHEntryShared::SetContentViewer(nsIContentViewer* aViewer)
   mContentViewer = aViewer;
 
   if (mContentViewer) {
-    EnsureHistoryTracker();
-    gHistoryTracker->AddObject(this);
+    // 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.
+    nsCOMPtr<nsISHistoryInternal> shistory = do_QueryReferent(mSHistory);
+    if (shistory) {
+      shistory->AddToExpirationTracker(this);
+    }
 
     nsCOMPtr<nsIDOMDocument> domDoc;
     mContentViewer->GetDOMDocument(getter_AddRefs(domDoc));

docshell/shistory/nsSHEntryShared.h

@@ -15,6 +15,7 @@
 #include "nsIMutationObserver.h"
 #include "nsRect.h"
 #include "nsString.h"
+#include "nsWeakPtr.h"
 
 #include "mozilla/Attributes.h"
 
@@ -54,12 +55,9 @@ private:
 
   friend class nsSHEntry;
 
-  friend class HistoryTracker;
-
   static already_AddRefed<nsSHEntryShared> Duplicate(nsSHEntryShared* aEntry);
 
   void RemoveFromExpirationTracker();
-  void Expire();
   nsresult SyncPresentationState();
   void DropPresentationState();
 
@@ -89,11 +87,14 @@ private:
   nsCOMPtr<nsIMutableArray> mRefreshURIList;
   nsExpirationState mExpirationState;
   nsAutoPtr<nsDocShellEditorData> mEditorData;
+  nsWeakPtr mSHistory;
 
   bool mIsFrameNavigation;
   bool mSaveLayoutState;
   bool mSticky;
   bool mDynamicallyCreated;
+
+  // This flag is about necko cache, not bfcache.
   bool mExpired;
 };
 

docshell/shistory/nsSHistory.cpp

@@ -32,11 +32,16 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
 #include "mozilla/StaticPtr.h"
+#include "mozilla/dom/TabGroup.h"
 
 using namespace mozilla;
 
 #define PREF_SHISTORY_SIZE "browser.sessionhistory.max_entries"
 #define PREF_SHISTORY_MAX_TOTAL_VIEWERS "browser.sessionhistory.max_total_viewers"
+#define CONTENT_VIEWER_TIMEOUT_SECONDS "browser.sessionhistory.contentViewerTimeout"
+
+// Default this to time out unused content viewers after 30 minutes
+#define CONTENT_VIEWER_TIMEOUT_SECONDS_DEFAULT (30 * 60)
 
 static const char* kObservedPrefs[] = {
   PREF_SHISTORY_SIZE,
@@ -251,6 +256,7 @@ NS_INTERFACE_MAP_BEGIN(nsSHistory)
   NS_INTERFACE_MAP_ENTRY(nsISHistory)
   NS_INTERFACE_MAP_ENTRY(nsIWebNavigation)
   NS_INTERFACE_MAP_ENTRY(nsISHistoryInternal)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
 NS_INTERFACE_MAP_END
 
 // static
@@ -379,6 +385,8 @@ nsSHistory::AddEntry(nsISHEntry* aSHEntry, bool aPersist)
 {
   NS_ENSURE_ARG(aSHEntry);
 
+  aSHEntry->SetSHistory(this);
+
   // If we have a root docshell, update the docshell id of the root shentry to
   // match the id of that docshell
   if (mRootDocShell) {
@@ -1296,6 +1304,30 @@ nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry* aEntry)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsSHistory::AddToExpirationTracker(nsIBFCacheEntry* aEntry)
+{
+  RefPtr<nsSHEntryShared> entry = static_cast<nsSHEntryShared*>(aEntry);
+  if (!mHistoryTracker || !entry) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mHistoryTracker->AddObject(entry);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSHistory::RemoveFromExpirationTracker(nsIBFCacheEntry* aEntry)
+{
+  RefPtr<nsSHEntryShared> entry = static_cast<nsSHEntryShared*>(aEntry);
+  if (!mHistoryTracker || !entry) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mHistoryTracker->RemoveObject(entry);
+  return NS_OK;
+}
+
 // Evicts all content viewers in all history objects.  This is very
 // inefficient, because it requires a linear search through all SHistory
 // objects for each viewer to be evicted.  However, this method is called
@@ -1896,6 +1928,23 @@ NS_IMETHODIMP
 nsSHistory::SetRootDocShell(nsIDocShell* aDocShell)
 {
   mRootDocShell = aDocShell;
+
+  // Init mHistoryTracker on setting mRootDocShell so we can bind its event
+  // target to the tabGroup.
+  if (mRootDocShell) {
+    nsCOMPtr<nsPIDOMWindowOuter> win = mRootDocShell->GetWindow();
+    if (!win) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    RefPtr<mozilla::dom::TabGroup> tabGroup = win->TabGroup();
+    mHistoryTracker = mozilla::MakeUnique<HistoryTracker>(
+      this,
+      mozilla::Preferences::GetUint(CONTENT_VIEWER_TIMEOUT_SECONDS,
+                                    CONTENT_VIEWER_TIMEOUT_SECONDS_DEFAULT),
+      tabGroup->EventTargetFor(mozilla::TaskCategory::Other));
+  }
+
   return NS_OK;
 }
 

docshell/shistory/nsSHistory.h

@@ -16,9 +16,10 @@
 #include "nsIWebNavigation.h"
 #include "nsSHEntryShared.h"
 #include "nsTObserverArray.h"
-#include "nsWeakPtr.h"
+#include "nsWeakReference.h"
 
 #include "mozilla/LinkedList.h"
+#include "mozilla/UniquePtr.h"
 
 class nsIDocShell;
 class nsSHEnumerator;
@@ -29,9 +30,37 @@ class nsISHTransaction;
 class nsSHistory final : public mozilla::LinkedListElement<nsSHistory>,
                          public nsISHistory,
                          public nsISHistoryInternal,
-                         public nsIWebNavigation
+                         public nsIWebNavigation,
+                         public nsSupportsWeakReference
 {
 public:
+
+  // The timer based history tracker is used to evict bfcache on expiration.
+  class HistoryTracker final : public nsExpirationTracker<nsSHEntryShared, 3>
+  {
+  public:
+    explicit HistoryTracker(nsSHistory* aSHistory,
+                            uint32_t aTimeout,
+                            nsIEventTarget* aEventTarget)
+      : nsExpirationTracker(1000 * aTimeout / 2, "HistoryTracker", aEventTarget)
+    {
+      MOZ_ASSERT(aSHistory);
+      mSHistory = aSHistory;
+    }
+
+  protected:
+    virtual void NotifyExpired(nsSHEntryShared* aObj)
+    {
+      RemoveObject(aObj);
+      mSHistory->EvictExpiredContentViewerForEntry(aObj);
+    }
+
+  private:
+    // HistoryTracker is owned by nsSHistory; it always outlives HistoryTracker
+    // so it's safe to use raw pointer here.
+    nsSHistory* mSHistory;
+  };
+
   nsSHistory();
   NS_DECL_ISUPPORTS
   NS_DECL_NSISHISTORY
@@ -87,6 +116,9 @@ private:
   // otherwise comparison is done to aIndex - 1.
   bool RemoveDuplicate(int32_t aIndex, bool aKeepNext);
 
+  // Track all bfcache entries and evict on expiration.
+  mozilla::UniquePtr<HistoryTracker> mHistoryTracker;
+
   nsCOMPtr<nsISHTransaction> mListRoot;
   int32_t mIndex;
   int32_t mLength;