Bug 1349699 - Assert when destroying a MessageLoop that a live MessageChannel is attached to (r=dvander)

MozReview-Commit-ID: GGr5UqJl3ui

ipc/glue/MessageChannel.cpp

@@ -488,8 +488,10 @@ private:
     nsAutoPtr<IPC::Message> mReply;
 };
 
-MessageChannel::MessageChannel(IToplevelProtocol *aListener)
-  : mListener(aListener),
+MessageChannel::MessageChannel(const char* aName,
+                               IToplevelProtocol *aListener)
+  : mName(aName),
+    mListener(aListener),
     mChannelState(ChannelClosed),
     mSide(UnknownSide),
     mLink(nullptr),
@@ -627,6 +629,14 @@ MessageChannel::CanSend() const
     return Connected();
 }
 
+void
+MessageChannel::WillDestroyCurrentMessageLoop()
+{
+    CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("ProtocolName"),
+                                       nsDependentCString(mName));
+    MOZ_CRASH("MessageLoop destroyed before MessageChannel that's bound to it");
+}
+
 void
 MessageChannel::Clear()
 {
@@ -644,6 +654,10 @@ MessageChannel::Clear()
         gParentProcessBlocker = nullptr;
     }
 
+    if (mWorkerLoop) {
+        mWorkerLoop->RemoveDestructionObserver(this);
+    }
+
     mWorkerLoop = nullptr;
     delete mLink;
     mLink = nullptr;
@@ -676,6 +690,8 @@ MessageChannel::Open(Transport* aTransport, MessageLoop* aIOLoop, Side aSide)
     mWorkerLoop = MessageLoop::current();
     mWorkerLoopID = mWorkerLoop->id();
 
+    mWorkerLoop->AddDestructionObserver(this);
+
     ProcessLink *link = new ProcessLink(this);
     link->Open(aTransport, aIOLoop, aSide); // :TODO: n.b.: sets mChild
     mLink = link;
@@ -752,6 +768,7 @@ MessageChannel::CommonThreadOpenInit(MessageChannel *aTargetChan, Side aSide)
 {
     mWorkerLoop = MessageLoop::current();
     mWorkerLoopID = mWorkerLoop->id();
+    mWorkerLoop->AddDestructionObserver(this);
     mLink = new ThreadLink(this, aTargetChan);
     mSide = aSide;
 }

ipc/glue/MessageChannel.h

@@ -72,7 +72,7 @@ enum ChannelState {
 
 class AutoEnterTransaction;
 
-class MessageChannel : HasResultCodes
+class MessageChannel : HasResultCodes, MessageLoop::DestructionObserver
 {
     friend class ProcessLink;
     friend class ThreadLink;
@@ -89,7 +89,8 @@ class MessageChannel : HasResultCodes
     typedef IPC::MessageInfo MessageInfo;
     typedef mozilla::ipc::Transport Transport;
 
-    explicit MessageChannel(IToplevelProtocol *aListener);
+    explicit MessageChannel(const char *aName,
+                            IToplevelProtocol *aListener);
     ~MessageChannel();
 
     IToplevelProtocol *Listener() const {
@@ -491,7 +492,12 @@ class MessageChannel : HasResultCodes
     typedef std::map<size_t, Message> MessageMap;
     typedef IPC::Message::msgid_t msgid_t;
 
+    void WillDestroyCurrentMessageLoop() override;
+
   private:
+    // This will be a string literal, so lifetime is not an issue.
+    const char* mName;
+
     // Based on presumption the listener owns and overlives the channel,
     // this is never nullified.
     IToplevelProtocol* mListener;

ipc/ipdl/ipdl/lower.py

@@ -2668,6 +2668,7 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
                 ExprMemberInit(ExprVar('mozilla::ipc::IToplevelProtocol'),
                                [_protocolId(ptype), side]),
                 ExprMemberInit(p.channelVar(), [
+                    ExprLiteral.String(_actorName(p.name, self.side)),
                     ExprCall(ExprVar('ALLOW_THIS_IN_INITIALIZER_LIST'),
                              [ ExprVar.THIS ]) ]),
                 ExprMemberInit(p.stateVar(),