From f80cfaf15ba9f369ed36d42b13e6f588948e6e9c Mon Sep 17 00:00:00 2001
From: Samael Wang <freesamael@gmail.com>
Date: Thu, 24 Aug 2017 14:32:23 +0800
Subject: [PATCH] Bug 1364364 - Part 2: Extract a part of
 EvictExpiredContentViewerForEntry to a new function
 FindTransactionForBFCache, and implement RemoveDynEntriesForEntry on top of
 it. r=smaug

MozReview-Commit-ID: EzK2U0c94v8

--HG--
extra : rebase_source : 472fae2733efae09157b8440c466a8c5ccc6b626
---
 docshell/shistory/nsISHistoryInternal.idl | 14 ++++++++
 docshell/shistory/nsSHistory.cpp          | 43 ++++++++++++++++++++---
 docshell/shistory/nsSHistory.h            |  6 ++++
 3 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/docshell/shistory/nsISHistoryInternal.idl b/docshell/shistory/nsISHistoryInternal.idl
index ae0a1facf073..22af9d85f8d2 100644
--- a/docshell/shistory/nsISHistoryInternal.idl
+++ b/docshell/shistory/nsISHistoryInternal.idl
@@ -120,6 +120,20 @@ interface nsISHistoryInternal: nsISupports
    [noscript, notxpcom] void RemoveDynEntries(in long aIndex,
                                               in nsISHContainer aContainer);
 
+   /**
+    * Similar to RemoveDynEntries, but instead of specifying an index, use the
+    * given BFCacheEntry to find the index and remove dynamic entries from the
+    * index.
+    *
+    * The method takes no effect if the bfcache entry is not or no longer hold
+    * by the SHistory instance.
+    *
+    * @param aEntry
+    *        The bfcache entry to look up for index to remove dynamic entries
+    *        from.
+    */
+   [noscript, notxpcom] void RemoveDynEntriesForBFCacheEntry(in nsIBFCacheEntry aEntry);
+
    /**
     * Removes entries from the history if their docshellID is in
     * aIDs array.
diff --git a/docshell/shistory/nsSHistory.cpp b/docshell/shistory/nsSHistory.cpp
index d36a7582fdb4..a3419d88bd3e 100644
--- a/docshell/shistory/nsSHistory.cpp
+++ b/docshell/shistory/nsSHistory.cpp
@@ -213,7 +213,7 @@ nsSHistory::EvictContentViewerForTransaction(nsISHTransaction* aTrans)
     LOG_SHENTRY_SPEC(("Evicting content viewer 0x%p for "
                       "owning SHEntry 0x%p at %s.",
                       viewer.get(), ownerEntry.get(), _spec),
-                     ownerEntry);
+                      ownerEntry);
 
     // Drop the presentation state before destroying the viewer, so that
     // document teardown is able to correctly persist the state.
@@ -1290,8 +1290,13 @@ nsSHistory::GloballyEvictContentViewers()
 }
 
 nsresult
-nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry* aEntry)
+nsSHistory::FindTransactionForBFCache(nsIBFCacheEntry* aEntry,
+                                      nsISHTransaction** aResult,
+                                      int32_t* aResultIndex)
 {
+  *aResult = nullptr;
+  *aResultIndex = -1;
+
   int32_t startIndex = std::max(0, mIndex - nsISHistory::VIEWER_WINDOW);
   int32_t endIndex = std::min(mLength - 1, mIndex + nsISHistory::VIEWER_WINDOW);
   nsCOMPtr<nsISHTransaction> trans;
@@ -1311,15 +1316,29 @@ nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry* aEntry)
     temp->GetNext(getter_AddRefs(trans));
   }
   if (i > endIndex) {
-    return NS_OK;
+    return NS_ERROR_FAILURE;
   }
 
-  if (i == mIndex) {
+  trans.forget(aResult);
+  *aResultIndex = i;
+  return NS_OK;
+}
+
+nsresult
+nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry* aEntry)
+{
+  int32_t index;
+  nsCOMPtr<nsISHTransaction> trans;
+  FindTransactionForBFCache(aEntry, getter_AddRefs(trans), &index);
+
+  if (index == mIndex) {
     NS_WARNING("How did the current SHEntry expire?");
     return NS_OK;
   }
 
-  EvictContentViewerForTransaction(trans);
+  if (trans) {
+    EvictContentViewerForTransaction(trans);
+  }
 
   return NS_OK;
 }
@@ -1586,6 +1605,20 @@ nsSHistory::RemoveDynEntries(int32_t aIndex, nsISHContainer* aContainer)
   }
 }
 
+void
+nsSHistory::RemoveDynEntriesForBFCacheEntry(nsIBFCacheEntry* aEntry)
+{
+  int32_t index;
+  nsCOMPtr<nsISHTransaction> trans;
+  FindTransactionForBFCache(aEntry, getter_AddRefs(trans), &index);
+  if (trans) {
+    nsCOMPtr<nsISHEntry> entry;
+    trans->GetSHEntry(getter_AddRefs(entry));
+    nsCOMPtr<nsISHContainer> container(do_QueryInterface(entry));
+    RemoveDynEntries(index, container);
+  }
+}
+
 NS_IMETHODIMP
 nsSHistory::UpdateIndex()
 {
diff --git a/docshell/shistory/nsSHistory.h b/docshell/shistory/nsSHistory.h
index a8933ad17763..41d0186e771b 100644
--- a/docshell/shistory/nsSHistory.h
+++ b/docshell/shistory/nsSHistory.h
@@ -96,6 +96,12 @@ private:
   nsresult PrintHistory();
 #endif
 
+  // Find the transaction 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,
+                                     nsISHTransaction** 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);