Bug 1696175 - Call DisconnectChildListeners at a later time for BFCache in the parent. r=necko-reviewers,nika

Differential Revision: https://phabricator.services.mozilla.com/D112981

docshell/base/BrowsingContext.cpp

@@ -2745,6 +2745,10 @@ void BrowsingContext::DidSet(FieldIndex<IDX_IsInBFCache>) {
         [&](BrowsingContext* aContext) { aContext->mIsInBFCache = false; });
   }
 
+  if (isInBFCache && XRE_IsContentProcess() && mDocShell) {
+    nsDocShell::Cast(mDocShell)->MaybeDisconnectChildListenersOnPageHide();
+  }
+
   PreOrderWalk([&](BrowsingContext* aContext) {
     nsCOMPtr<nsIDocShell> shell = aContext->GetDocShell();
     if (shell) {

docshell/base/nsDocShell.cpp

@@ -88,6 +88,7 @@
 #include "mozilla/dom/JSWindowActorChild.h"
 #include "mozilla/ipc/ProtocolUtils.h"
 #include "mozilla/net/DocumentChannel.h"
+#include "mozilla/net/DocumentChannelChild.h"
 #include "mozilla/net/ParentChannelWrapper.h"
 #include "mozilla/net/UrlClassifierFeatureFactory.h"
 #include "ReferrerInfo.h"
@@ -383,6 +384,7 @@ nsDocShell::nsDocShell(BrowsingContext* aBrowsingContext,
       mFailedLoadType(0),
       mJSRunToCompletionDepth(0),
       mMetaViewportOverride(nsIDocShell::META_VIEWPORT_OVERRIDE_NONE),
+      mChannelToDisconnectOnPageHide(0),
       mCreatingDocument(false),
 #ifdef DEBUG
       mInEnsureScriptEnv(false),
@@ -4369,6 +4371,11 @@ nsDocShell::Stop(uint32_t aStopFlags) {
     // just call Stop() on us as an nsIDocumentLoader... We need fewer
     // redundant apis!
     Stop();
+
+    // Clear out mChannelToDisconnectOnPageHide. This page won't go in the
+    // BFCache now, and the Stop above will have removed the DocumentChannel
+    // from the loadgroup.
+    mChannelToDisconnectOnPageHide = 0;
   }
 
   for (auto* child : mChildList.ForwardRange()) {
@@ -13625,3 +13632,20 @@ nsDocShell::OnStopRequest(nsIRequest* aRequest, nsresult aStatusCode) {
   RecordSingleChannelId();
   return nsDocLoader::OnStopRequest(aRequest, aStatusCode);
 }
+
+void nsDocShell::MaybeDisconnectChildListenersOnPageHide() {
+  MOZ_RELEASE_ASSERT(XRE_IsContentProcess());
+
+  if (mChannelToDisconnectOnPageHide != 0 && mLoadGroup) {
+    nsCOMPtr<nsISimpleEnumerator> requests;
+    mLoadGroup->GetRequests(getter_AddRefs(requests));
+    for (const auto& request : SimpleEnumerator<nsIRequest>(requests)) {
+      RefPtr<DocumentChannel> channel = do_QueryObject(request);
+      if (channel && channel->ChannelId() == mChannelToDisconnectOnPageHide) {
+        static_cast<DocumentChannelChild*>(channel.get())
+            ->DisconnectChildListeners(NS_BINDING_ABORTED, NS_BINDING_ABORTED);
+      }
+    }
+    mChannelToDisconnectOnPageHide = 0;
+  }
+}

docshell/base/nsDocShell.h

@@ -1088,6 +1088,12 @@ class nsDocShell final : public nsDocLoader,
 
   void RecordSingleChannelId();
 
+  void SetChannelToDisconnectOnPageHide(uint64_t aChannelId) {
+    MOZ_ASSERT(mChannelToDisconnectOnPageHide == 0);
+    mChannelToDisconnectOnPageHide = aChannelId;
+  }
+  void MaybeDisconnectChildListenersOnPageHide();
+
  private:  // data members
   nsString mTitle;
   nsCString mOriginalUriString;
@@ -1227,6 +1233,8 @@ class nsDocShell final : public nsDocLoader,
   // See WindowGlobalParent::mSingleChannelId.
   mozilla::Maybe<uint64_t> mSingleChannelId;
 
+  uint64_t mChannelToDisconnectOnPageHide;
+
   // The following two fields cannot be declared as bit fields
   // because of uses with AutoRestore.
   bool mCreatingDocument;  // (should be) debugging only

netwerk/ipc/DocumentChannel.h

@@ -55,6 +55,9 @@ class DocumentChannel : public nsIIdentChannel {
     mInitialClientInfo = aInfo;
   }
 
+  void DisconnectChildListeners(const nsresult& aStatus,
+                                const nsresult& aLoadGroupStatus);
+
   /**
    * Will create the appropriate document channel:
    * Either a DocumentChannelChild if called from the content process or
@@ -77,8 +80,6 @@ class DocumentChannel : public nsIIdentChannel {
                   bool aIsXFOError);
 
   void ShutdownListeners(nsresult aStatusCode);
-  void DisconnectChildListeners(const nsresult& aStatus,
-                                const nsresult& aLoadGroupStatus);
   virtual void DeleteIPDL() {}
 
   nsDocShell* GetDocShell();

netwerk/ipc/DocumentChannelChild.cpp

@@ -192,20 +192,29 @@ IPCResult DocumentChannelChild::RecvFailedAsyncOpen(
 IPCResult DocumentChannelChild::RecvDisconnectChildListeners(
     const nsresult& aStatus, const nsresult& aLoadGroupStatus,
     bool aSwitchedProcess) {
-  // If this is a normal failure, then we want to disconnect our listeners and
-  // notify them of the failure. If this is a process switch, then we can just
-  // ignore it silently, and trust that the switch will shut down our docshell
-  // and cancel us when it's ready.
-  // XXXBFCache This should be fixed in some better way.
-  bool disconnectChildListeners = !aSwitchedProcess;
-  if (!disconnectChildListeners && mozilla::BFCacheInParent()) {
-    nsDocShell* shell = GetDocShell();
-    disconnectChildListeners = shell && shell->GetBrowsingContext() &&
-                               shell->GetBrowsingContext()->IsTop();
-  }
-  if (disconnectChildListeners) {
+  // If this disconnect is not due to a process switch, perform the disconnect
+  // immediately.
+  if (!aSwitchedProcess) {
     DisconnectChildListeners(aStatus, aLoadGroupStatus);
+    return IPC_OK();
   }
+
+  // Otherwise, the disconnect will occur later using some other mechanism,
+  // depending on what's happening to the loading DocShell. If this is a
+  // toplevel navigation, and this BrowsingContext enters the BFCache, we will
+  // cancel this channel when the PageHide event is firing, whereas if it does
+  // not enter BFCache (e.g. due to being an object, subframe or non-bfcached
+  // toplevel navigation), we will cancel this channel when the DocShell is
+  // destroyed.
+  nsDocShell* shell = GetDocShell();
+  if (mLoadInfo->GetExternalContentPolicyType() ==
+          ExtContentPolicy::TYPE_DOCUMENT &&
+      shell) {
+    MOZ_ASSERT(shell->GetBrowsingContext()->IsTop());
+    // Tell the DocShell which channel to cancel if it enters the BFCache.
+    shell->SetChannelToDisconnectOnPageHide(mChannelId);
+  }
+
   return IPC_OK();
 }