Bug 1215140 P10 Avoid AddRef'ing the nsIChannel OMT. r=bz

dom/workers/ServiceWorkerEvents.cpp

@@ -109,9 +109,11 @@ AsyncLog(nsIInterceptedChannel *aInterceptedChannel,
          const nsACString& aMessageName, const nsTArray<nsString>& aParams)
 {
   MOZ_ASSERT(aInterceptedChannel);
-  nsCOMPtr<nsIChannel> inner;
-  aInterceptedChannel->GetChannel(getter_AddRefs(inner));
-  nsCOMPtr<nsIConsoleReportCollector> reporter = do_QueryInterface(inner);
+  // Since the intercepted channel is kept alive and paused while handling
+  // the FetchEvent, we are guaranteed the reporter is stable on the worker
+  // thread.
+  nsIConsoleReportCollector* reporter =
+    aInterceptedChannel->GetConsoleReportCollector();
   if (reporter) {
     reporter->AddConsoleReport(nsIScriptError::errorFlag,
                                NS_LITERAL_CSTRING("Service Worker Interception"),

modules/libjar/InterceptedJARChannel.cpp

@@ -146,3 +146,9 @@ InterceptedJARChannel::NotifyController()
   }
   mController = nullptr;
 }
+
+nsIConsoleReportCollector*
+InterceptedJARChannel::GetConsoleReportCollector() const
+{
+  return nullptr;
+}

modules/libjar/InterceptedJARChannel.h

@@ -53,6 +53,9 @@ public:
   NS_DECL_NSIINTERCEPTEDCHANNEL
 
   void NotifyController();
+
+  virtual nsIConsoleReportCollector*
+  GetConsoleReportCollector() const override;
 };
 
 } // namespace net

netwerk/base/nsINetworkInterceptController.idl

@@ -11,6 +11,7 @@ interface nsIOutputStream;
 interface nsIURI;
 
 %{C++
+#include "nsIConsoleReportCollector.h"
 namespace mozilla {
 namespace dom {
 class ChannelInfo;
@@ -27,7 +28,7 @@ class ChannelInfo;
  * which do not implement nsIChannel.
  */
 
-[scriptable, uuid(afe6aae6-a80d-405b-856e-df36c19bf3c8)]
+[scriptable, uuid(ea78e439-cc42-4b2d-a42b-85ab55a149d1)]
 interface nsIInterceptedChannel : nsISupports
 {
     /**
@@ -85,6 +86,18 @@ interface nsIInterceptedChannel : nsISupports
      */
     [noscript]
     readonly attribute nsContentPolicyType internalContentPolicyType;
+
+%{C++
+    // Allow access to the inner channel as a ConsoleReportCollector off
+    // the main thread.  Pure C++ method here to avoid requiring an
+    // AddRef() during QI.  Callers should not save the returned pointer.
+    // May return nullptr.
+    //
+    // Note: Only safe to use OMT prior to resetInterception(),
+    //       finishSynthesizedResponse(), and cancel().
+    virtual nsIConsoleReportCollector*
+    GetConsoleReportCollector() const = 0;
+%}
 };
 
 /**

netwerk/protocol/http/InterceptedChannel.cpp

@@ -134,6 +134,16 @@ InterceptedChannelChrome::NotifyController()
   DoNotifyController();
 }
 
+nsIConsoleReportCollector*
+InterceptedChannelChrome::GetConsoleReportCollector() const
+{
+  // The ConsoleReportCollector should only be used when the inner channel is
+  // stable.  Nothing should try to use it once we return to the main thread
+  // and clear the inner channel.
+  MOZ_ASSERT(mChannel);
+  return mChannel;
+}
+
 NS_IMETHODIMP
 InterceptedChannelChrome::GetChannel(nsIChannel** aChannel)
 {
@@ -312,6 +322,16 @@ InterceptedChannelContent::NotifyController()
   DoNotifyController();
 }
 
+nsIConsoleReportCollector*
+InterceptedChannelContent::GetConsoleReportCollector() const
+{
+  // The ConsoleReportCollector should only be used when the inner channel is
+  // stable.  Nothing should try to use it once we return to the main thread
+  // and clear the inner channel.
+  MOZ_ASSERT(mChannel);
+  return mChannel;
+}
+
 NS_IMETHODIMP
 InterceptedChannelContent::GetChannel(nsIChannel** aChannel)
 {

netwerk/protocol/http/InterceptedChannel.h

@@ -82,6 +82,9 @@ public:
   NS_IMETHOD GetInternalContentPolicyType(nsContentPolicyType *aInternalContentPolicyType) override;
 
   virtual void NotifyController() override;
+
+  virtual nsIConsoleReportCollector*
+  GetConsoleReportCollector() const override;
 };
 
 class InterceptedChannelContent : public InterceptedChannelBase
@@ -110,6 +113,9 @@ public:
   NS_IMETHOD GetInternalContentPolicyType(nsContentPolicyType *aInternalContentPolicyType) override;
 
   virtual void NotifyController() override;
+
+  virtual nsIConsoleReportCollector*
+  GetConsoleReportCollector() const override;
 };
 
 } // namespace net