Bug 1488321 - Remove all traces of the "transaction" terminology in SHistory. r=nika.

This patch: - removes GetTransactionAtIndex(), because getTransactionAtIndex() can be used instead; - renames a lot of things; - updates some comments. --HG-- extra : rebase_source : 845a1c1d5fe7f84eaa03db39a344d98fd5784afd
2018-09-05 09:03:22 +10:00 · 2018-09-05 09:03:22 +10:00 · f5d9c8867c
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@ -322,8 +322,8 @@ nsDocShell::nsDocShell()
  , mMarginWidth(-1)
  , mMarginHeight(-1)
  , mItemType(typeContent)
-  , mPreviousTransIndex(-1)
-  , mLoadedTransIndex(-1)
+  , mPreviousEntryIndex(-1)
+  , mLoadedEntryIndex(-1)
  , mChildOffset(0)
  , mSandboxFlags(0)
  , mBusyFlags(BUSY_FLAGS_NONE)
@ -2286,16 +2286,16 @@ nsDocShell::SetUseErrorPages(bool aUseErrorPages)
 }

 NS_IMETHODIMP
-nsDocShell::GetPreviousTransIndex(int32_t* aPreviousTransIndex)
+nsDocShell::GetPreviousEntryIndex(int32_t* aPreviousEntryIndex)
 {
-  *aPreviousTransIndex = mPreviousTransIndex;
+  *aPreviousEntryIndex = mPreviousEntryIndex;
  return NS_OK;
 }

 NS_IMETHODIMP
-nsDocShell::GetLoadedTransIndex(int32_t* aLoadedTransIndex)
+nsDocShell::GetLoadedEntryIndex(int32_t* aLoadedEntryIndex)
 {
-  *aLoadedTransIndex = mLoadedTransIndex;
+  *aLoadedEntryIndex = mLoadedEntryIndex;
  return NS_OK;
 }

@ -2307,8 +2307,8 @@ nsDocShell::HistoryPurged(int32_t aNumEntries)
  // eviction.  We need to adjust by the number of entries that we
  // just purged from history, so that we look at the right session history
  // entries during eviction.
-  mPreviousTransIndex = std::max(-1, mPreviousTransIndex - aNumEntries);
-  mLoadedTransIndex = std::max(0, mLoadedTransIndex - aNumEntries);
+  mPreviousEntryIndex = std::max(-1, mPreviousEntryIndex - aNumEntries);
+  mLoadedEntryIndex = std::max(0, mLoadedEntryIndex - aNumEntries);

  nsTObserverArray<nsDocLoader*>::ForwardIterator iter(mChildList);
  while (iter.HasMore()) {
@ -2322,29 +2322,29 @@ nsDocShell::HistoryPurged(int32_t aNumEntries)
 }

 nsresult
-nsDocShell::HistoryTransactionRemoved(int32_t aIndex)
+nsDocShell::HistoryEntryRemoved(int32_t aIndex)
 {
  // These indices are used for fastback cache eviction, to determine
  // which session history entries are candidates for content viewer
  // eviction.  We need to adjust by the number of entries that we
  // just purged from history, so that we look at the right session history
  // entries during eviction.
-  if (aIndex == mPreviousTransIndex) {
-    mPreviousTransIndex = -1;
-  } else if (aIndex < mPreviousTransIndex) {
-    --mPreviousTransIndex;
+  if (aIndex == mPreviousEntryIndex) {
+    mPreviousEntryIndex = -1;
+  } else if (aIndex < mPreviousEntryIndex) {
+    --mPreviousEntryIndex;
  }
-  if (mLoadedTransIndex == aIndex) {
-    mLoadedTransIndex = 0;
-  } else if (aIndex < mLoadedTransIndex) {
-    --mLoadedTransIndex;
+  if (mLoadedEntryIndex == aIndex) {
+    mLoadedEntryIndex = 0;
+  } else if (aIndex < mLoadedEntryIndex) {
+    --mLoadedEntryIndex;
  }

  nsTObserverArray<nsDocLoader*>::ForwardIterator iter(mChildList);
  while (iter.HasMore()) {
    nsCOMPtr<nsIDocShell> shell = do_QueryObject(iter.GetNext());
    if (shell) {
-      static_cast<nsDocShell*>(shell.get())->HistoryTransactionRemoved(aIndex);
+      static_cast<nsDocShell*>(shell.get())->HistoryEntryRemoved(aIndex);
    }
  }

@ -3866,7 +3866,7 @@ nsDocShell::AddChildSHEntryToParent(nsISHEntry* aNewEntry, int32_t aChildOffset,
  // current index by 1
  RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();
  if (rootSH) {
-    mPreviousTransIndex = rootSH->Index();
+    mPreviousEntryIndex = rootSH->Index();
  }

  nsresult rv;
@ -3877,10 +3877,10 @@ nsDocShell::AddChildSHEntryToParent(nsISHEntry* aNewEntry, int32_t aChildOffset,
  }

  if (rootSH) {
-    mLoadedTransIndex = rootSH->Index();
+    mLoadedEntryIndex = rootSH->Index();
 #ifdef DEBUG_PAGE_CACHE
-    printf("Previous index: %d, Loaded index: %d\n\n", mPreviousTransIndex,
-           mLoadedTransIndex);
+    printf("Previous index: %d, Loaded index: %d\n\n", mPreviousEntryIndex,
+           mLoadedEntryIndex);
 #endif
  }

@ -8120,12 +8120,12 @@ nsDocShell::RestoreFromHistory()
  mURIResultedInDocument = true;
  RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();
  if (rootSH) {
-    mPreviousTransIndex = rootSH->Index();
+    mPreviousEntryIndex = rootSH->Index();
    rootSH->LegacySHistory()->UpdateIndex();
-    mLoadedTransIndex = rootSH->Index();
+    mLoadedEntryIndex = rootSH->Index();
 #ifdef DEBUG_PAGE_CACHE
-    printf("Previous index: %d, Loaded index: %d\n\n", mPreviousTransIndex,
-           mLoadedTransIndex);
+    printf("Previous index: %d, Loaded index: %d\n\n", mPreviousEntryIndex,
+           mLoadedEntryIndex);
 #endif
  }

@ -11607,12 +11607,12 @@ nsDocShell::OnNewURI(nsIURI* aURI, nsIChannel* aChannel,
  if (rootSH &&
       ((mLoadType & (LOAD_CMD_HISTORY | LOAD_CMD_RELOAD)) ||
         mLoadType == LOAD_NORMAL_REPLACE)) {
-    mPreviousTransIndex = rootSH->Index();
+    mPreviousEntryIndex = rootSH->Index();
    rootSH->LegacySHistory()->UpdateIndex();
-    mLoadedTransIndex = rootSH->Index();
+    mLoadedEntryIndex = rootSH->Index();
 #ifdef DEBUG_PAGE_CACHE
    printf("Previous index: %d, Loaded index: %d\n\n",
-           mPreviousTransIndex, mLoadedTransIndex);
+           mPreviousEntryIndex, mLoadedEntryIndex);
 #endif
  }

@ -12254,14 +12254,14 @@ nsDocShell::AddToSessionHistory(nsIURI* aURI, nsIChannel* aChannel,

    if (addToSHistory) {
      // Add to session history
-      mPreviousTransIndex = mSessionHistory->Index();
+      mPreviousEntryIndex = mSessionHistory->Index();

      bool shouldPersist = ShouldAddToSessionHistory(aURI, aChannel);
      rv = mSessionHistory->LegacySHistory()->AddEntry(entry, shouldPersist);
-      mLoadedTransIndex = mSessionHistory->Index();
+      mLoadedEntryIndex = mSessionHistory->Index();
 #ifdef DEBUG_PAGE_CACHE
      printf("Previous index: %d, Loaded index: %d\n\n",
-             mPreviousTransIndex, mLoadedTransIndex);
+             mPreviousEntryIndex, mLoadedEntryIndex);
 #endif
    }
  } else {
--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@ -254,7 +254,7 @@ public:
                         LOCATION_CHANGE_SAME_DOCUMENT);
  }

-  nsresult HistoryTransactionRemoved(int32_t aIndex);
+  nsresult HistoryEntryRemoved(int32_t aIndex);

  // Notify Scroll observers when an async panning/zooming transform
  // has started being applied
@ -1031,11 +1031,11 @@ private: // data members
  // Create() is called, the type is not expected to change.
  int32_t mItemType;

-  // Index into the SHTransaction list, indicating the previous and current
-  // transaction at the time that this DocShell begins to load. Consequently
+  // Index into the nsISHEntry array, indicating the previous and current
+  // entry at the time that this DocShell begins to load. Consequently
  // root docshell's indices can differ from child docshells'.
-  int32_t mPreviousTransIndex;
-  int32_t mLoadedTransIndex;
+  int32_t mPreviousEntryIndex;
+  int32_t mLoadedEntryIndex;

  // Offset in the parent's child list.
  // -1 if the docshell is added dynamically to the parent shell.
--- a/docshell/base/nsIDocShell.idl
+++ b/docshell/base/nsIDocShell.idl
@ -539,12 +539,12 @@ interface nsIDocShell : nsIDocShellTreeItem
  readonly attribute nsIChannel failedChannel;

  /**
-   * Keeps track of the previous SHTransaction index and the current
-   * SHTransaction index at the time that the doc shell begins to load.
+   * Keeps track of the previous nsISHEntry index and the current
+   * nsISHEntry index at the time that the doc shell begins to load.
   * Used for ContentViewer eviction.
   */
-  readonly attribute long previousTransIndex;
-  readonly attribute long loadedTransIndex;
+  readonly attribute long previousEntryIndex;
+  readonly attribute long loadedEntryIndex;

  /**
   * Notification that entries have been removed from the beginning of a
--- a/docshell/shistory/nsISHEntry.idl
+++ b/docshell/shistory/nsISHEntry.idl
@ -402,7 +402,7 @@ interface nsISHEntry : nsISupports
    void ReplaceChild(in nsISHEntry aNewChild);

    /**
-     * When an entry is serving as a transaction within nsISHistory, this
+     * When an entry is serving is within nsISHistory's array of entries, this
     * property specifies if it should persist. If not it will be replaced by
     * new additions to the list.
     */
--- a/docshell/shistory/nsISHistory.idl
+++ b/docshell/shistory/nsISHistory.idl
@ -68,14 +68,11 @@ interface nsISHistory: nsISupports
  attribute long maxLength;

  /**
-   * Get the history entry at a given index.
+   * Get the history entry at a given index. Returns non-null on success.
   *
   * @param index             The index value whose entry is requested.
   *                          The oldest entry is located at index == 0.
-   * @return                  <code>NS_OK</code> history entry for
-   *                          the index is obtained successfully.
-   *                          <code>NS_ERROR_FAILURE</code> Error in obtaining
-   *                          history entry for the given index.
+   * @return                  The found entry; never null.
   */
  nsISHEntry getEntryAtIndex(in long aIndex);

@ -151,11 +148,6 @@ interface nsISHistory: nsISupports
   */
  void addEntry(in nsISHEntry aEntry, in boolean aPersist);

-  /**
-   * Get the transaction at a particular index. Returns non-null on success.
-   */
-  nsISHEntry GetTransactionAtIndex(in int32_t aIndex);
-
  /**
   * Sets the toplevel docshell object to which this SHistory object belongs to.
   */
--- a/docshell/shistory/nsSHistory.cpp
+++ b/docshell/shistory/nsSHistory.cpp
@ -184,11 +184,11 @@ nsSHistoryObserver::Observe(nsISupports* aSubject, const char* aTopic,
 namespace {

 already_AddRefed<nsIContentViewer>
-GetContentViewerForTransaction(nsISHEntry* aTrans)
+GetContentViewerForEntry(nsISHEntry* aEntry)
 {
  nsCOMPtr<nsISHEntry> ownerEntry;
  nsCOMPtr<nsIContentViewer> viewer;
-  aTrans->GetAnyContentViewer(getter_AddRefs(ownerEntry),
+  aEntry->GetAnyContentViewer(getter_AddRefs(ownerEntry),
                              getter_AddRefs(viewer));
  return viewer.forget();
 }
@ -196,11 +196,11 @@ GetContentViewerForTransaction(nsISHEntry* aTrans)
 } // namespace

 void
-nsSHistory::EvictContentViewerForTransaction(nsISHEntry* aTrans)
+nsSHistory::EvictContentViewerForEntry(nsISHEntry* aEntry)
 {
  nsCOMPtr<nsIContentViewer> viewer;
  nsCOMPtr<nsISHEntry> ownerEntry;
-  aTrans->GetAnyContentViewer(getter_AddRefs(ownerEntry),
+  aEntry->GetAnyContentViewer(getter_AddRefs(ownerEntry),
                              getter_AddRefs(viewer));
  if (viewer) {
    NS_ASSERTION(ownerEntry, "Content viewer exists but its SHEntry is null");
@ -219,9 +219,9 @@ nsSHistory::EvictContentViewerForTransaction(nsISHEntry* aTrans)

  // When dropping bfcache, we have to remove associated dynamic entries as well.
  int32_t index = -1;
-  GetIndexOfEntry(aTrans, &index);
+  GetIndexOfEntry(aEntry, &index);
  if (index != -1) {
-    RemoveDynEntries(index, aTrans);
+    RemoveDynEntries(index, aEntry);
  }
 }

@ -609,7 +609,7 @@ nsSHistory::AddEntry(nsISHEntry* aSHEntry, bool aPersist)

  nsCOMPtr<nsISHEntry> currentTxn;
  if (mIndex >= 0) {
-    nsresult rv = GetTransactionAtIndex(mIndex, getter_AddRefs(currentTxn));
+    nsresult rv = GetEntryAtIndex(mIndex, getter_AddRefs(currentTxn));
    NS_ENSURE_SUCCESS(rv, rv);
  }

@ -625,7 +625,7 @@ nsSHistory::AddEntry(nsISHEntry* aSHEntry, bool aPersist)
  if (currentTxn && !currentTxn->GetPersist()) {
    NOTIFY_LISTENERS(OnHistoryReplaceEntry, (mIndex));
    aSHEntry->SetPersist(aPersist);
-    mTransactions[mIndex] = aSHEntry;
+    mEntries[mIndex] = aSHEntry;
    return NS_OK;
  }

@ -633,12 +633,12 @@ nsSHistory::AddEntry(nsISHEntry* aSHEntry, bool aPersist)
  aSHEntry->GetURI(getter_AddRefs(uri));
  NOTIFY_LISTENERS(OnHistoryNewEntry, (uri, mIndex));

-  // Remove all transactions after the current one, add the new one, and set
-  // the new one as the current one.
+  // Remove all entries after the current one, add the new one, and set the new
+  // one as the current one.
  MOZ_ASSERT(mIndex >= -1);
  aSHEntry->SetPersist(aPersist);
-  mTransactions.TruncateLength(mIndex + 1);
-  mTransactions.AppendElement(aSHEntry);
+  mEntries.TruncateLength(mIndex + 1);
+  mEntries.AppendElement(aSHEntry);
  mIndex++;

  NOTIFY_LISTENERS(OnLengthChanged, (Length()));
@ -693,13 +693,6 @@ nsSHistory::GetRequestedIndex(int32_t* aResult)

 NS_IMETHODIMP
 nsSHistory::GetEntryAtIndex(int32_t aIndex, nsISHEntry** aResult)
-{
-  return GetTransactionAtIndex(aIndex, aResult);
-}
-
-/* Get the transaction at a given index */
-NS_IMETHODIMP
-nsSHistory::GetTransactionAtIndex(int32_t aIndex, nsISHEntry** aResult)
 {
  NS_ENSURE_ARG_POINTER(aResult);

@ -707,7 +700,7 @@ nsSHistory::GetTransactionAtIndex(int32_t aIndex, nsISHEntry** aResult)
    return NS_ERROR_FAILURE;
  }

-  *aResult = mTransactions[aIndex];
+  *aResult = mEntries[aIndex];
  NS_ADDREF(*aResult);
  return NS_OK;
 }
@ -721,7 +714,7 @@ nsSHistory::GetIndexOfEntry(nsISHEntry* aSHEntry, int32_t* aResult)
  *aResult = -1;

  for (int32_t i = 0; i < Length(); i++) {
-    if (aSHEntry == mTransactions[i]) {
+    if (aSHEntry == mEntries[i]) {
      *aResult = i;
      return NS_OK;
    }
@ -735,7 +728,7 @@ nsresult
 nsSHistory::PrintHistory()
 {
  for (int32_t i = 0; i < Length(); i++) {
-    nsCOMPtr<nsISHEntry> entry = mTransactions[i];
+    nsCOMPtr<nsISHEntry> entry = mEntries[i];
    nsCOMPtr<nsILayoutHistoryState> layoutHistoryState;
    nsCOMPtr<nsIURI> uri;
    nsString title;
@ -750,7 +743,7 @@ nsSHistory::PrintHistory()
      uri->GetSpec(url);
    }

-    printf("**** SH Transaction #%d, Entry = %x\n", i, entry.get());
+    printf("**** SH Entry #%d: %x\n", i, entry.get());
    printf("\t\t URL = %s\n", url.get());

    printf("\t\t Title = %s\n", NS_LossyConvertUTF16toASCII(title).get());
@ -813,7 +806,7 @@ nsSHistory::PurgeHistory(int32_t aNumEntries)
  }

  // Remove the first `aNumEntries` entries.
-  mTransactions.RemoveElementsAt(0, aNumEntries);
+  mEntries.RemoveElementsAt(0, aNumEntries);

  // Adjust the indices, but don't let them go below -1.
  mIndex -= aNumEntries;
@ -884,7 +877,7 @@ nsSHistory::ReplaceEntry(int32_t aIndex, nsISHEntry* aReplaceEntry)
  NOTIFY_LISTENERS(OnHistoryReplaceEntry, (aIndex));

  aReplaceEntry->SetPersist(true);
-  mTransactions[aIndex] = aReplaceEntry;
+  mEntries[aIndex] = aReplaceEntry;

  return NS_OK;
 }
@ -914,7 +907,7 @@ nsSHistory::EvictAllContentViewers()
  // XXXbz we don't actually do a good job of evicting things as we should, so
  // we might have viewers quite far from mIndex.  So just evict everything.
  for (int32_t i = 0; i < Length(); i++) {
-    EvictContentViewerForTransaction(mTransactions[i]);
+    EvictContentViewerForEntry(mEntries[i]);
  }

  return NS_OK;
@ -982,11 +975,11 @@ nsSHistory::EvictOutOfRangeWindowContentViewers(int32_t aIndex)
  //
  // to ensure that this SHistory object isn't responsible for more than
  // VIEWER_WINDOW content viewers.  But our job is complicated by the
-  // fact that two transactions which are related by either hash navigations or
+  // fact that two entries which are related by either hash navigations or
  // history.pushState will have the same content viewer.
  //
  // To illustrate the issue, suppose VIEWER_WINDOW = 3 and we have four
-  // linked transactions in our history.  Suppose we then add a new content
+  // linked entries in our history.  Suppose we then add a new content
  // viewer and call into this function.  So the history looks like:
  //
  //   A A A A B
@ -1027,8 +1020,7 @@ nsSHistory::EvictOutOfRangeWindowContentViewers(int32_t aIndex)
  // if it appears outside this range.
  nsCOMArray<nsIContentViewer> safeViewers;
  for (int32_t i = startSafeIndex; i <= endSafeIndex; i++) {
-    nsCOMPtr<nsIContentViewer> viewer =
-      GetContentViewerForTransaction(mTransactions[i]);
+    nsCOMPtr<nsIContentViewer> viewer = GetContentViewerForEntry(mEntries[i]);
    safeViewers.AppendObject(viewer);
  }

@ -1036,32 +1028,32 @@ nsSHistory::EvictOutOfRangeWindowContentViewers(int32_t aIndex)
  // (It's important that the condition checks Length(), rather than a cached
  // copy of Length(), because the length might change between iterations.)
  for (int32_t i = 0; i < Length(); i++) {
-    nsCOMPtr<nsISHEntry> trans = mTransactions[i];
-    nsCOMPtr<nsIContentViewer> viewer = GetContentViewerForTransaction(trans);
+    nsCOMPtr<nsISHEntry> entry = mEntries[i];
+    nsCOMPtr<nsIContentViewer> viewer = GetContentViewerForEntry(entry);
    if (safeViewers.IndexOf(viewer) == -1) {
-      EvictContentViewerForTransaction(trans);
+      EvictContentViewerForEntry(entry);
    }
  }
 }

 namespace {

-class TransactionAndDistance
+class EntryAndDistance
 {
 public:
-  TransactionAndDistance(nsSHistory* aSHistory, nsISHEntry* aTrans, uint32_t aDist)
+  EntryAndDistance(nsSHistory* aSHistory, nsISHEntry* aEntry, uint32_t aDist)
    : mSHistory(aSHistory)
-    , mTransaction(aTrans)
+    , mEntry(aEntry)
    , mLastTouched(0)
    , mDistance(aDist)
  {
-    mViewer = GetContentViewerForTransaction(aTrans);
-    NS_ASSERTION(mViewer, "Transaction should have a content viewer");
+    mViewer = GetContentViewerForEntry(aEntry);
+    NS_ASSERTION(mViewer, "Entry should have a content viewer");

-    mTransaction->GetLastTouched(&mLastTouched);
+    mEntry->GetLastTouched(&mLastTouched);
  }

-  bool operator<(const TransactionAndDistance& aOther) const
+  bool operator<(const EntryAndDistance& aOther) const
  {
    // Compare distances first, and fall back to last-accessed times.
    if (aOther.mDistance != this->mDistance) {
@ -1071,17 +1063,17 @@ public:
    return this->mLastTouched < aOther.mLastTouched;
  }

-  bool operator==(const TransactionAndDistance& aOther) const
+  bool operator==(const EntryAndDistance& aOther) const
  {
    // This is a little silly; we need == so the default comaprator can be
    // instantiated, but this function is never actually called when we sort
-    // the list of TransactionAndDistance objects.
+    // the list of EntryAndDistance objects.
    return aOther.mDistance == this->mDistance &&
           aOther.mLastTouched == this->mLastTouched;
  }

  RefPtr<nsSHistory> mSHistory;
-  nsCOMPtr<nsISHEntry> mTransaction;
+  nsCOMPtr<nsISHEntry> mEntry;
  nsCOMPtr<nsIContentViewer> mViewer;
  uint32_t mLastTouched;
  int32_t mDistance;
@ -1093,18 +1085,18 @@ public:
 void
 nsSHistory::GloballyEvictContentViewers()
 {
-  // First, collect from each SHistory object the transactions which have a
-  // cached content viewer.  Associate with each transaction its distance from
-  // its SHistory's current index.
+  // First, collect from each SHistory object the entries which have a cached
+  // content viewer. Associate with each entry its distance from its SHistory's
+  // current index.

-  nsTArray<TransactionAndDistance> transactions;
+  nsTArray<EntryAndDistance> entries;

  for (auto shist : gSHistoryList) {

-    // Maintain a list of the transactions which have viewers and belong to
+    // Maintain a list of the entries which have viewers and belong to
    // this particular shist object.  We'll add this list to the global list,
-    // |transactions|, eventually.
-    nsTArray<TransactionAndDistance> shTransactions;
+    // |entries|, eventually.
+    nsTArray<EntryAndDistance> shEntries;

    // Content viewers are likely to exist only within shist->mIndex -/+
    // VIEWER_WINDOW, so only search within that range.
@ -1122,18 +1114,18 @@ nsSHistory::GloballyEvictContentViewers()
    int32_t startIndex, endIndex;
    shist->WindowIndices(shist->mIndex, &startIndex, &endIndex);
    for (int32_t i = startIndex; i <= endIndex; i++) {
-      nsCOMPtr<nsISHEntry> trans = shist->mTransactions[i];
+      nsCOMPtr<nsISHEntry> entry = shist->mEntries[i];
      nsCOMPtr<nsIContentViewer> contentViewer =
-        GetContentViewerForTransaction(trans);
+        GetContentViewerForEntry(entry);

      if (contentViewer) {
        // Because one content viewer might belong to multiple SHEntries, we
-        // have to search through shTransactions to see if we already know
+        // have to search through shEntries to see if we already know
        // about this content viewer.  If we find the viewer, update its
        // distance from the SHistory's index and continue.
        bool found = false;
-        for (uint32_t j = 0; j < shTransactions.Length(); j++) {
-          TransactionAndDistance& container = shTransactions[j];
+        for (uint32_t j = 0; j < shEntries.Length(); j++) {
+          EntryAndDistance& container = shEntries[j];
          if (container.mViewer == contentViewer) {
            container.mDistance = std::min(container.mDistance,
                                           DeprecatedAbs(i - shist->mIndex));
@ -1142,44 +1134,43 @@ nsSHistory::GloballyEvictContentViewers()
          }
        }

-        // If we didn't find a TransactionAndDistance for this content viewer,
-        // make a new one.
+        // If we didn't find a EntryAndDistance for this content viewer, make a
+        // new one.
        if (!found) {
-          TransactionAndDistance container(shist, trans,
-                                           DeprecatedAbs(i - shist->mIndex));
-          shTransactions.AppendElement(container);
+          EntryAndDistance container(shist, entry,
+                                     DeprecatedAbs(i - shist->mIndex));
+          shEntries.AppendElement(container);
        }
      }
    }

-    // We've found all the transactions belonging to shist which have viewers.
-    // Add those transactions to our global list and move on.
-    transactions.AppendElements(shTransactions);
+    // We've found all the entries belonging to shist which have viewers.
+    // Add those entries to our global list and move on.
+    entries.AppendElements(shEntries);
  }

  // We now have collected all cached content viewers.  First check that we
  // have enough that we actually need to evict some.
-  if ((int32_t)transactions.Length() <= sHistoryMaxTotalViewers) {
+  if ((int32_t)entries.Length() <= sHistoryMaxTotalViewers) {
    return;
  }

-  // If we need to evict, sort our list of transactions and evict the largest
+  // If we need to evict, sort our list of entries and evict the largest
  // ones.  (We could of course get better algorithmic complexity here by using
  // a heap or something more clever.  But sHistoryMaxTotalViewers isn't large,
  // so let's not worry about it.)
-  transactions.Sort();
+  entries.Sort();

-  for (int32_t i = transactions.Length() - 1; i >= sHistoryMaxTotalViewers;
+  for (int32_t i = entries.Length() - 1; i >= sHistoryMaxTotalViewers;
       --i) {
-    (transactions[i].mSHistory)->
-      EvictContentViewerForTransaction(transactions[i].mTransaction);
+    (entries[i].mSHistory)->EvictContentViewerForEntry(entries[i].mEntry);
  }
 }

 nsresult
-nsSHistory::FindTransactionForBFCache(nsIBFCacheEntry* aEntry,
-                                      nsISHEntry** aResult,
-                                      int32_t* aResultIndex)
+nsSHistory::FindEntryForBFCache(nsIBFCacheEntry* aBFEntry,
+                                nsISHEntry** aResult,
+                                int32_t* aResultIndex)
 {
  *aResult = nullptr;
  *aResultIndex = -1;
@ -1188,11 +1179,11 @@ nsSHistory::FindTransactionForBFCache(nsIBFCacheEntry* aEntry,
  WindowIndices(mIndex, &startIndex, &endIndex);

  for (int32_t i = startIndex; i <= endIndex; ++i) {
-    nsCOMPtr<nsISHEntry> trans = mTransactions[i];
+    nsCOMPtr<nsISHEntry> shEntry = mEntries[i];

-    // Does entry have the same BFCacheEntry as the argument to this method?
-    if (trans->HasBFCacheEntry(aEntry)) {
-      trans.forget(aResult);
+    // Does shEntry have the same BFCacheEntry as the argument to this method?
+    if (shEntry->HasBFCacheEntry(aBFEntry)) {
+      shEntry.forget(aResult);
      *aResultIndex = i;
      return NS_OK;
    }
@ -1201,28 +1192,28 @@ nsSHistory::FindTransactionForBFCache(nsIBFCacheEntry* aEntry,
 }

 nsresult
-nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry* aEntry)
+nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry* aBFEntry)
 {
  int32_t index;
-  nsCOMPtr<nsISHEntry> trans;
-  FindTransactionForBFCache(aEntry, getter_AddRefs(trans), &index);
+  nsCOMPtr<nsISHEntry> shEntry;
+  FindEntryForBFCache(aBFEntry, getter_AddRefs(shEntry), &index);

  if (index == mIndex) {
    NS_WARNING("How did the current SHEntry expire?");
    return NS_OK;
  }

-  if (trans) {
-    EvictContentViewerForTransaction(trans);
+  if (shEntry) {
+    EvictContentViewerForEntry(shEntry);
  }

  return NS_OK;
 }

 NS_IMETHODIMP
-nsSHistory::AddToExpirationTracker(nsIBFCacheEntry* aEntry)
+nsSHistory::AddToExpirationTracker(nsIBFCacheEntry* aBFEntry)
 {
-  RefPtr<nsSHEntryShared> entry = static_cast<nsSHEntryShared*>(aEntry);
+  RefPtr<nsSHEntryShared> entry = static_cast<nsSHEntryShared*>(aBFEntry);
  if (!mHistoryTracker || !entry) {
    return NS_ERROR_FAILURE;
  }
@ -1232,9 +1223,9 @@ nsSHistory::AddToExpirationTracker(nsIBFCacheEntry* aEntry)
 }

 NS_IMETHODIMP
-nsSHistory::RemoveFromExpirationTracker(nsIBFCacheEntry* aEntry)
+nsSHistory::RemoveFromExpirationTracker(nsIBFCacheEntry* aBFEntry)
 {
-  RefPtr<nsSHEntryShared> entry = static_cast<nsSHEntryShared*>(aEntry);
+  RefPtr<nsSHEntryShared> entry = static_cast<nsSHEntryShared*>(aBFEntry);
  MOZ_ASSERT(mHistoryTracker && !mHistoryTracker->IsEmpty());
  if (!mHistoryTracker || !entry) {
    return NS_ERROR_FAILURE;
@ -1368,19 +1359,19 @@ nsSHistory::RemoveDuplicate(int32_t aIndex, bool aKeepNext)
  NS_ENSURE_SUCCESS(rv, false);

  if (IsSameTree(root1, root2)) {
-    mTransactions.RemoveElementAt(aIndex);
+    mEntries.RemoveElementAt(aIndex);

    if (mRootDocShell) {
-      static_cast<nsDocShell*>(mRootDocShell)->HistoryTransactionRemoved(aIndex);
+      static_cast<nsDocShell*>(mRootDocShell)->HistoryEntryRemoved(aIndex);
    }

-    // Adjust our indices to reflect the removed transaction
+    // Adjust our indices to reflect the removed entry.
    if (mIndex > aIndex) {
      mIndex = mIndex - 1;
      NOTIFY_LISTENERS(OnIndexChanged, (mIndex));
    }

-    // NB: If the transaction we are removing is the transaction currently
+    // NB: If the entry we are removing is the entry currently
    // being navigated to (mRequestedIndex) then we adjust the index
    // only if we're not keeping the next entry (because if we are keeping
    // the next entry (because the current is a duplicate of the next), then
@ -1444,13 +1435,13 @@ nsSHistory::RemoveDynEntries(int32_t aIndex, nsISHEntry* aEntry)
 }

 void
-nsSHistory::RemoveDynEntriesForBFCacheEntry(nsIBFCacheEntry* aEntry)
+nsSHistory::RemoveDynEntriesForBFCacheEntry(nsIBFCacheEntry* aBFEntry)
 {
  int32_t index;
-  nsCOMPtr<nsISHEntry> trans;
-  FindTransactionForBFCache(aEntry, getter_AddRefs(trans), &index);
-  if (trans) {
-    RemoveDynEntries(index, trans);
+  nsCOMPtr<nsISHEntry> shEntry;
+  FindEntryForBFCache(aBFEntry, getter_AddRefs(shEntry), &index);
+  if (shEntry) {
+    RemoveDynEntries(index, shEntry);
  }
 }

--- a/docshell/shistory/nsSHistory.h
+++ b/docshell/shistory/nsSHistory.h
@ -143,16 +143,16 @@ private:
  nsresult PrintHistory();
 #endif

-  // Find the transaction for a given bfcache entry. It only looks up between
+  // Find the history entry for a given bfcache entry. It only looks up between
  // the range where alive viewers may exist (i.e nsISHistory::VIEWER_WINDOW).
-  nsresult FindTransactionForBFCache(nsIBFCacheEntry* aEntry,
-                                     nsISHEntry** aResult,
-                                     int32_t* aResultIndex);
+  nsresult FindEntryForBFCache(nsIBFCacheEntry* aBFEntry,
+                               nsISHEntry** aResult,
+                               int32_t* aResultIndex);

  // Evict content viewers in this window which don't lie in the "safe" range
  // around aIndex.
  void EvictOutOfRangeWindowContentViewers(int32_t aIndex);
-  void EvictContentViewerForTransaction(nsISHEntry* aTrans);
+  void EvictContentViewerForEntry(nsISHEntry* aEntry);
  static void GloballyEvictContentViewers();
  static void GloballyEvictAllContentViewers();

@ -163,7 +163,7 @@ private:
  nsresult LoadNextPossibleEntry(int32_t aNewIndex, long aLoadType,
                                 uint32_t aHistCmd);

-  // aIndex is the index of the transaction which may be removed.
+  // aIndex is the index of the entry which may be removed.
  // If aKeepNext is true, aIndex is compared to aIndex + 1,
  // otherwise comparison is done to aIndex - 1.
  bool RemoveDuplicate(int32_t aIndex, bool aKeepNext);
@ -171,15 +171,15 @@ private:
  // Track all bfcache entries and evict on expiration.
  mozilla::UniquePtr<HistoryTracker> mHistoryTracker;

-  nsTArray<nsCOMPtr<nsISHEntry>> mTransactions; // entries are never null
+  nsTArray<nsCOMPtr<nsISHEntry>> mEntries; // entries are never null
  int32_t mIndex;           // -1 means "no index"
  int32_t mRequestedIndex;  // -1 means "no requested index"

  void WindowIndices(int32_t aIndex, int32_t* aOutStartIndex,
                     int32_t* aOutEndIndex);

-  // Length of mTransactions.
-  int32_t Length() { return int32_t(mTransactions.Length()); }
+  // Length of mEntries.
+  int32_t Length() { return int32_t(mEntries.Length()); }

  // Session History listeners
  nsAutoTObserverArray<nsWeakPtr, 2> mListeners;
--- a/docshell/test/navigation/file_bug1326251.html
+++ b/docshell/test/navigation/file_bug1326251.html
@ -49,8 +49,8 @@
        let shistory = docShell.QueryInterface(SpecialPowers.Ci.nsIWebNavigation)
                               .sessionHistory;
        // Now staticFrame has frame0 -> frame1 -> frame2.
-        opener.is(docShell.previousTransIndex, 3, 'docShell.previousTransIndex');
-        opener.is(docShell.loadedTransIndex, 2, 'docShell.loadedTransIndex');
+        opener.is(docShell.previousEntryIndex, 3, 'docShell.previousEntryIndex');
+        opener.is(docShell.loadedEntryIndex, 2, 'docShell.loadedEntryIndex');
        opener.is(shistory.index, 2, 'shistory.index');
        opener.is(history.length, 4, 'history.length');
        opener.is(document.getElementById('staticFrame').contentWindow.location.href, BASE_URL + 'frame2.html', 'staticFrame location');
@ -109,8 +109,8 @@
                               .sessionHistory;
        // staticFrame:       frame0 -> frame1 -> frame2 -> iframe_static
        // innerStaticFrame:                                frame0        -> frame1
-        opener.is(docShell.previousTransIndex, 5, 'docShell.previousTransIndex');
-        opener.is(docShell.loadedTransIndex, 4, 'docShell.loadedTransIndex');
+        opener.is(docShell.previousEntryIndex, 5, 'docShell.previousEntryIndex');
+        opener.is(docShell.loadedEntryIndex, 4, 'docShell.loadedEntryIndex');
        opener.is(shistory.index, 4, 'shistory.index');
        opener.is(history.length, 6, 'history.length');
        let staticFrame = document.getElementById('staticFrame');
--- a/docshell/test/navigation/file_bug534178.html
+++ b/docshell/test/navigation/file_bug534178.html
@ -12,7 +12,7 @@
          isOK = true;
        }
        document.body.textContent = isOK ? "PASSED" : "FAILED";
-        opener.ok(isOK, "Duplicate session history transactions should have been removed!");
+        opener.ok(isOK, "Duplicate session history entries should have been removed!");
        opener.nextTest();
        window.close();
      }
--- a/docshell/test/navigation/test_sessionhistory.html
+++ b/docshell/test/navigation/test_sessionhistory.html
@ -26,7 +26,7 @@ var testFiles =
    "file_bug508537_1.html",         // Dynamic frames and forward-back
    "file_document_write_1.html",    // Session history + document.write
    //"file_static_and_dynamic_1.html",// Static and dynamic frames and forward-back
-    "file_bug534178.html",           // Session history transaction clean-up.
+    "file_bug534178.html",           // Session history entry clean-up.
    "file_fragment_handling_during_load.html",
    "file_nested_frames.html",
    "file_shiftReload_and_pushState.html",
--- a/layout/base/nsDocumentViewer.cpp
+++ b/layout/base/nsDocumentViewer.cpp
@ -2247,8 +2247,8 @@ nsDocumentViewer::Show(void)
      if (history) {
        int32_t prevIndex,loadedIndex;
        nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(treeItem);
-        docShell->GetPreviousTransIndex(&prevIndex);
-        docShell->GetLoadedTransIndex(&loadedIndex);
+        docShell->GetPreviousEntryIndex(&prevIndex);
+        docShell->GetLoadedEntryIndex(&loadedIndex);
 #ifdef DEBUG_PAGE_CACHE
        printf("About to evict content viewers: prev=%d, loaded=%d\n",
               prevIndex, loadedIndex);
--- a/toolkit/modules/sessionstore/SessionHistory.jsm
+++ b/toolkit/modules/sessionstore/SessionHistory.jsm
@ -84,12 +84,12 @@ var SessionHistoryInternal = {
      let shistory = history.legacySHistory.QueryInterface(Ci.nsISHistory);
      let count = shistory.count;
      for ( ; entryCount < count; entryCount++) {
-        let txn = shistory.GetTransactionAtIndex(entryCount);
+        let shEntry = shistory.getEntryAtIndex(entryCount);
        if (entryCount <= aFromIdx) {
          skippedCount++;
          continue;
        }
-        let entry = this.serializeEntry(txn);
+        let entry = this.serializeEntry(shEntry);
        data.entries.push(entry);
      }