From 92a5efa31be74b8a55c23bf94f92d8a390e67299 Mon Sep 17 00:00:00 2001
From: Marco Castelluccio <mcastelluccio@mozilla.com>
Date: Wed, 16 Sep 2020 01:18:46 +0000
Subject: [PATCH] Bug 1662407 - Call nsSHistory::GotoIndex directly when
 loading from session history in the parent process. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D88976

UltraBlame original commit: a23e9879c8485e6717c9f2519cc5a40031a8b3ec
---
 docshell/base/BrowsingContext.cpp          | 12 ++++++++++++
 docshell/base/BrowsingContext.h            |  2 ++
 docshell/base/CanonicalBrowsingContext.cpp | 17 +++++++++++++++++
 docshell/base/CanonicalBrowsingContext.h   |  2 ++
 docshell/shistory/ChildSHistory.cpp        | 15 +++++++--------
 dom/ipc/ContentParent.cpp                  | 11 ++---------
 6 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/docshell/base/BrowsingContext.cpp b/docshell/base/BrowsingContext.cpp
index fe4a817a96ef..481db5b7e5b3 100644
--- a/docshell/base/BrowsingContext.cpp
+++ b/docshell/base/BrowsingContext.cpp
@@ -2714,6 +2714,18 @@ void BrowsingContext::RemoveFromSessionHistory() {
   }
 }
 
+void BrowsingContext::HistoryGo(int32_t aIndex,
+                                std::function<void(int32_t&&)>&& aResolver) {
+  if (XRE_IsContentProcess()) {
+    ContentChild::GetSingleton()->SendHistoryGo(
+        this, aIndex, std::move(aResolver),
+        [](mozilla::ipc::
+               ResponseRejectReason) {  });
+  } else {
+    Canonical()->HistoryGo(aIndex, std::move(aResolver));
+  }
+}
+
 }  
 
 namespace ipc {
diff --git a/docshell/base/BrowsingContext.h b/docshell/base/BrowsingContext.h
index 0b472f14d761..7f6fad430af6 100644
--- a/docshell/base/BrowsingContext.h
+++ b/docshell/base/BrowsingContext.h
@@ -672,6 +672,8 @@ class BrowsingContext : public nsILoadContext, public nsWrapperCache {
   Tuple<nsCOMPtr<nsIPrincipal>, nsCOMPtr<nsIPrincipal>>
   GetTriggeringAndInheritPrincipalsForCurrentLoad();
 
+  void HistoryGo(int32_t aIndex, std::function<void(int32_t&&)>&& aResolver);
+
  protected:
   virtual ~BrowsingContext();
   BrowsingContext(WindowContext* aParentWindow, BrowsingContextGroup* aGroup,
diff --git a/docshell/base/CanonicalBrowsingContext.cpp b/docshell/base/CanonicalBrowsingContext.cpp
index 67067ab9986a..5e44a71f60fa 100644
--- a/docshell/base/CanonicalBrowsingContext.cpp
+++ b/docshell/base/CanonicalBrowsingContext.cpp
@@ -514,6 +514,23 @@ void CanonicalBrowsingContext::RemoveFromSessionHistory() {
   }
 }
 
+void CanonicalBrowsingContext::HistoryGo(
+    int32_t aIndex, std::function<void(int32_t&&)>&& aResolver) {
+  nsSHistory* shistory = static_cast<nsSHistory*>(GetSessionHistory());
+  if (!shistory) {
+    return;
+  }
+
+  nsTArray<nsSHistory::LoadEntryResult> loadResults;
+  nsresult rv = shistory->GotoIndex(aIndex, loadResults);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  aResolver(shistory->GetRequestedIndex());
+  nsSHistory::LoadURIs(loadResults);
+}
+
 JSObject* CanonicalBrowsingContext::WrapObject(
     JSContext* aCx, JS::Handle<JSObject*> aGivenProto) {
   return CanonicalBrowsingContext_Binding::Wrap(aCx, this, aGivenProto);
diff --git a/docshell/base/CanonicalBrowsingContext.h b/docshell/base/CanonicalBrowsingContext.h
index a91696c95ddd..70f830fde99f 100644
--- a/docshell/base/CanonicalBrowsingContext.h
+++ b/docshell/base/CanonicalBrowsingContext.h
@@ -126,6 +126,8 @@ class CanonicalBrowsingContext final : public BrowsingContext {
 
   void RemoveFromSessionHistory();
 
+  void HistoryGo(int32_t aIndex, std::function<void(int32_t&&)>&& aResolver);
+
   JSObject* WrapObject(JSContext* aCx,
                        JS::Handle<JSObject*> aGivenProto) override;
 
diff --git a/docshell/shistory/ChildSHistory.cpp b/docshell/shistory/ChildSHistory.cpp
index 3cc040f63c48..36d7b7c30c17 100644
--- a/docshell/shistory/ChildSHistory.cpp
+++ b/docshell/shistory/ChildSHistory.cpp
@@ -137,21 +137,20 @@ void ChildSHistory::Go(int32_t aOffset, bool aRequireUserInteraction,
         index.value() <= 0) {
       break;
     }
-    if (mHistory->HasUserInteractionAtIndex(index.value())) {
+    if (mHistory && mHistory->HasUserInteractionAtIndex(index.value())) {
       break;
     }
   }
 
   if (StaticPrefs::fission_sessionHistoryInParent()) {
     nsCOMPtr<nsISHistory> shistory = mHistory;
-    ContentChild::GetSingleton()->SendHistoryGo(
-        mBrowsingContext, index.value(),
-        [shistory](int32_t&& aRequestedIndex) {
+    mBrowsingContext->HistoryGo(
+        index.value(), [shistory](int32_t&& aRequestedIndex) {
           
-          shistory->InternalSetRequestedIndex(aRequestedIndex);
-        },
-        [](mozilla::ipc::
-               ResponseRejectReason) {  });
+          if (shistory) {
+            shistory->InternalSetRequestedIndex(aRequestedIndex);
+          }
+        });
   } else {
     aRv = mHistory->GotoIndex(index.value());
   }
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 2968239b0219..5416b2fe1d21 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -6941,15 +6941,8 @@ mozilla::ipc::IPCResult ContentParent::RecvHistoryGo(
     const MaybeDiscarded<BrowsingContext>& aContext, int32_t aIndex,
     HistoryGoResolver&& aResolveRequestedIndex) {
   if (!aContext.IsDiscarded()) {
-    nsSHistory* shistory =
-        static_cast<nsSHistory*>(aContext.get_canonical()->GetSessionHistory());
-    nsTArray<nsSHistory::LoadEntryResult> loadResults;
-    nsresult rv = shistory->GotoIndex(aIndex, loadResults);
-    if (NS_FAILED(rv)) {
-      return IPC_FAIL(this, "GotoIndex failed");
-    }
-    aResolveRequestedIndex(shistory->GetRequestedIndex());
-    shistory->LoadURIs(loadResults);
+    aContext.get_canonical()->HistoryGo(aIndex,
+                                        std::move(aResolveRequestedIndex));
   }
   return IPC_OK();
 }