Bug 1359245 - Get rid of CycleCollectedJSRuntime::MainContext (r=mccr8)

This is another method that assumes one context per runtime. This patch
eliminates the method.

MozReview-Commit-ID: JHcQ1nyiHSP

dom/workers/RuntimeService.cpp

@@ -1059,7 +1059,7 @@ public:
     MOZ_ASSERT(aWorkerPrivate);
   }
 
-  void Shutdown() override
+  void Shutdown(JSContext* cx) override
   {
     // The CC is shut down, and the superclass destructor will GC, so make sure
     // we don't try to CC again.

js/xpconnect/src/XPCJSContext.cpp

@@ -790,7 +790,7 @@ XPCJSContext::Initialize()
     if (!xpc_LocalizeContext(cx))
         NS_RUNTIMEABORT("xpc_LocalizeContext failed.");
 
-    Runtime()->Initialize();
+    Runtime()->Initialize(cx);
 
     return NS_OK;
 }

js/xpconnect/src/XPCJSRuntime.cpp

@@ -673,7 +673,8 @@ void XPCJSRuntime::TraceNativeBlackRoots(JSTracer* trc)
     for (e = mObjectHolderRoots; e; e = e->GetNextRoot())
         static_cast<XPCJSObjectHolder*>(e)->TraceJS(trc);
 
-    dom::TraceBlackJS(trc, JS_GetGCParameter(MainContext(), JSGC_NUMBER),
+    JSContext* cx = XPCJSContext::Get()->Context();
+    dom::TraceBlackJS(trc, JS_GetGCParameter(cx, JSGC_NUMBER),
                       nsXPConnect::XPConnect()->IsShuttingDown());
 }
 
@@ -1075,8 +1076,7 @@ CompartmentPrivate::SizeOfIncludingThis(MallocSizeOf mallocSizeOf)
 static void
 ReloadPrefsCallback(const char* pref, void* data)
 {
-    XPCJSRuntime* xpcrt = reinterpret_cast<XPCJSRuntime*>(data);
-    JSContext* cx = xpcrt->MainContext();
+    JSContext* cx = XPCJSContext::Get()->Context();
 
     bool safeMode = false;
     nsCOMPtr<nsIXULRuntime> xr = do_GetService("@mozilla.org/xre/runtime;1");
@@ -1168,21 +1168,17 @@ ReloadPrefsCallback(const char* pref, void* data)
 }
 
 void
-XPCJSRuntime::Shutdown()
+XPCJSRuntime::Shutdown(JSContext* cx)
 {
-    // Elsewhere we abort immediately if XPCJSRuntime initialization fails.
-    // Therefore the context must be non-null.
-    MOZ_ASSERT(MainContext());
-
     // This destructor runs before ~CycleCollectedJSContext, which does the
     // actual JS_DestroyContext() call. But destroying the context triggers
     // one final GC, which can call back into the context with various
     // callbacks if we aren't careful. Null out the relevant callbacks.
-    JS_RemoveFinalizeCallback(MainContext(), FinalizeCallback);
-    JS_RemoveWeakPointerZonesCallback(MainContext(), WeakPointerZonesCallback);
-    JS_RemoveWeakPointerCompartmentCallback(MainContext(), WeakPointerCompartmentCallback);
+    JS_RemoveFinalizeCallback(cx, FinalizeCallback);
+    JS_RemoveWeakPointerZonesCallback(cx, WeakPointerZonesCallback);
+    JS_RemoveWeakPointerCompartmentCallback(cx, WeakPointerCompartmentCallback);
 
-    JS::SetGCSliceCallback(MainContext(), mPrevGCSliceCallback);
+    JS::SetGCSliceCallback(cx, mPrevGCSliceCallback);
 
     // We don't want to track wrapped JS roots after this point since we're
     // making them !IsValid anyway through SystemIsBeingShutDown.
@@ -1212,10 +1208,10 @@ XPCJSRuntime::Shutdown()
     mDyingWrappedNativeProtoMap = nullptr;
 
     Preferences::UnregisterPrefixCallback(ReloadPrefsCallback,
-                                          JS_OPTIONS_DOT_STR, this);
+                                          JS_OPTIONS_DOT_STR);
 
 #ifdef FUZZING
-    Preferences::UnregisterCallback(ReloadPrefsCallback, "fuzzing.enabled", this);
+    Preferences::UnregisterCallback(ReloadPrefsCallback, "fuzzing.enabled");
 #endif
 }
 
@@ -2472,7 +2468,8 @@ JSReporter::CollectReports(WindowPaths* windowPaths,
     XPCJSRuntimeStats rtStats(windowPaths, topWindowPaths, getLocations,
                               anonymize);
     OrphanReporter orphanReporter(XPCConvert::GetISupportsFromJSObject);
-    if (!JS::CollectRuntimeStats(xpcrt->MainContext(), &rtStats, &orphanReporter,
+    JSContext* cx = XPCJSContext::Get()->Context();
+    if (!JS::CollectRuntimeStats(cx, &rtStats, &orphanReporter,
                                  anonymize))
     {
         return;
@@ -2961,11 +2958,8 @@ XPCJSRuntime::Get()
 }
 
 void
-XPCJSRuntime::Initialize()
+XPCJSRuntime::Initialize(JSContext* cx)
 {
-    MOZ_ASSERT(MainContext());
-    JSContext* cx = MainContext();
-
     mUnprivilegedJunkScope.init(cx, nullptr);
     mPrivilegedJunkScope.init(cx, nullptr);
     mCompilationScope.init(cx, nullptr);
@@ -3025,12 +3019,12 @@ XPCJSRuntime::Initialize()
     mozilla::RegisterJSSizeOfTab(JSSizeOfTab);
 
     // Watch for the JS boolean options.
-    ReloadPrefsCallback(nullptr, this);
+    ReloadPrefsCallback(nullptr, nullptr);
     Preferences::RegisterPrefixCallback(ReloadPrefsCallback,
-                                        JS_OPTIONS_DOT_STR, this);
+                                        JS_OPTIONS_DOT_STR);
 
 #ifdef FUZZING
-    Preferences::RegisterCallback(ReloadPrefsCallback, "fuzzing.enabled", this);
+    Preferences::RegisterCallback(ReloadPrefsCallback, "fuzzing.enabled");
 #endif
 }
 
@@ -3108,7 +3102,6 @@ XPCJSRuntime::DebugDump(int16_t depth)
     depth--;
     XPC_LOG_ALWAYS(("XPCJSRuntime @ %p", this));
         XPC_LOG_INDENT();
-        XPC_LOG_ALWAYS(("mJSContext @ %p", MainContext()));
 
         XPC_LOG_ALWAYS(("mWrappedJSClassMap @ %p with %d wrapperclasses(s)",
                         mWrappedJSClassMap, mWrappedJSClassMap->Count()));
@@ -3213,7 +3206,7 @@ void
 XPCJSRuntime::InitSingletonScopes()
 {
     // This all happens very early, so we don't bother with cx pushing.
-    JSContext* cx = MainContext();
+    JSContext* cx = XPCJSContext::Get()->Context();
     JSAutoRequest ar(cx);
     RootedValue v(cx);
     nsresult rv;

js/xpconnect/src/XPCWrappedJS.cpp

@@ -470,8 +470,10 @@ XPCJSRuntime::AssertInvalidWrappedJSNotInTable(nsXPCWrappedJS* wrapper) const
 #ifdef DEBUG
     if (!wrapper->IsValid()) {
         MOZ_ASSERT(!GetMultiCompartmentWrappedJSMap()->HasWrapper(wrapper));
-        if (!mGCIsRunning)
-            JS_IterateCompartments(MainContext(), wrapper, NotHasWrapperAssertionCallback);
+        if (!mGCIsRunning) {
+            JSContext* cx = XPCJSContext::Get()->Context();
+            JS_IterateCompartments(cx, wrapper, NotHasWrapperAssertionCallback);
+        }
     }
 #endif
 }

js/xpconnect/src/xpcprivate.h

@@ -642,8 +642,8 @@ private:
     explicit XPCJSRuntime(JSContext* aCx);
 
     MOZ_IS_CLASS_INIT
-    void Initialize();
-    void Shutdown() override;
+    void Initialize(JSContext* cx);
+    void Shutdown(JSContext* cx) override;
 
     void ReleaseIncrementally(nsTArray<nsISupports*>& array);
 

xpcom/base/CycleCollectedJSContext.cpp

@@ -68,7 +68,7 @@ CycleCollectedJSContext::~CycleCollectedJSContext()
     return;
   }
 
-  mRuntime->Shutdown();
+  mRuntime->Shutdown(mJSContext);
 
   // Last chance to process any events.
   ProcessMetastableStateQueue(mBaseRecursionDepth);

xpcom/base/CycleCollectedJSRuntime.cpp

@@ -550,7 +550,7 @@ CycleCollectedJSRuntime::CycleCollectedJSRuntime(JSContext* aMainContext)
 }
 
 void
-CycleCollectedJSRuntime::Shutdown()
+CycleCollectedJSRuntime::Shutdown(JSContext* cx)
 {
 }
 
@@ -1248,7 +1248,7 @@ CycleCollectedJSRuntime::DeferredFinalize(nsISupports* aSupports)
 void
 CycleCollectedJSRuntime::DumpJSHeap(FILE* aFile)
 {
-  js::DumpHeap(MainContext(), aFile, js::CollectNurseryBeforeDump);
+  js::DumpHeap(mJSContext, aFile, js::CollectNurseryBeforeDump);
 }
 
 IncrementalFinalizeRunnable::IncrementalFinalizeRunnable(CycleCollectedJSRuntime* aRt,
@@ -1466,7 +1466,7 @@ void
 CycleCollectedJSRuntime::PrepareWaitingZonesForGC()
 {
   if (mZonesWaitingForGC.Count() == 0) {
-    JS::PrepareForFullGC(MainContext());
+    JS::PrepareForFullGC(mJSContext);
   } else {
     for (auto iter = mZonesWaitingForGC.Iter(); !iter.Done(); iter.Next()) {
       JS::PrepareZoneForGC(iter.Get()->GetKey());

xpcom/base/CycleCollectedJSRuntime.h

@@ -110,7 +110,7 @@ protected:
   CycleCollectedJSRuntime(JSContext* aMainContext);
   virtual ~CycleCollectedJSRuntime();
 
-  virtual void Shutdown();
+  virtual void Shutdown(JSContext* cx);
 
   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
   void UnmarkSkippableJSHolders();
@@ -275,14 +275,6 @@ public:
   // full GC.
   void PrepareWaitingZonesForGC();
 
-  // The main context is the first one created in the runtime and the last one
-  // destroyed.
-  JSContext* MainContext() const
-  {
-    MOZ_ASSERT(mJSContext);
-    return mJSContext;
-  }
-
   // Get the current thread's CycleCollectedJSRuntime.  Returns null if there
   // isn't one.
   static CycleCollectedJSRuntime* Get();