Bug 1052052 - Hoist AutoCxPusher into ScriptSettings.h. r=gabor

content/base/public/nsContentUtils.h

@@ -24,6 +24,7 @@
 #include "mozilla/GuardObjects.h"
 #include "mozilla/TimeStamp.h"
 #include "nsContentListDeclarations.h"
+#include "nsCxPusher.h"
 #include "nsMathUtils.h"
 #include "nsTArrayForwardDeclare.h"
 #include "Units.h"

dom/base/ScriptSettings.cpp

@@ -9,6 +9,7 @@
 #include "mozilla/Assertions.h"
 
 #include "jsapi.h"
+#include "xpcprivate.h" // For AutoCxPusher guts
 #include "xpcpublic.h"
 #include "nsIGlobalObject.h"
 #include "nsIScriptGlobalObject.h"
@@ -18,6 +19,7 @@
 #include "nsPIDOMWindow.h"
 #include "nsTArray.h"
 #include "nsJSUtils.h"
+#include "nsDOMJSUtils.h"
 
 namespace mozilla {
 namespace dom {
@@ -373,5 +375,66 @@ AutoNoJSAPI::AutoNoJSAPI(bool aIsMainThread)
   }
 }
 
+danger::AutoCxPusher::AutoCxPusher(JSContext* cx, bool allowNull)
+{
+  MOZ_ASSERT_IF(!allowNull, cx);
+
+  // Hold a strong ref to the nsIScriptContext, if any. This ensures that we
+  // only destroy the mContext of an nsJSContext when it is not on the cx stack
+  // (and therefore not in use). See nsJSContext::DestroyJSContext().
+  if (cx)
+    mScx = GetScriptContextFromJSContext(cx);
+
+  XPCJSContextStack *stack = XPCJSRuntime::Get()->GetJSContextStack();
+  if (!stack->Push(cx)) {
+    MOZ_CRASH();
+  }
+  mStackDepthAfterPush = stack->Count();
+
+#ifdef DEBUG
+  mPushedContext = cx;
+  mCompartmentDepthOnEntry = cx ? js::GetEnterCompartmentDepth(cx) : 0;
+#endif
+
+  // Enter a request and a compartment for the duration that the cx is on the
+  // stack if non-null.
+  if (cx) {
+    mAutoRequest.emplace(cx);
+
+    // DOM JSContexts don't store their default compartment object on the cx.
+    JSObject *compartmentObject = mScx ? mScx->GetWindowProxy()
+                                       : js::DefaultObjectForContextOrNull(cx);
+    if (compartmentObject)
+      mAutoCompartment.emplace(cx, compartmentObject);
+  }
+}
+
+danger::AutoCxPusher::~AutoCxPusher()
+{
+  // Leave the compartment and request before popping.
+  mAutoCompartment.reset();
+  mAutoRequest.reset();
+
+  // When we push a context, we may save the frame chain and pretend like we
+  // haven't entered any compartment. This gets restored on Pop(), but we can
+  // run into trouble if a Push/Pop are interleaved with a
+  // JSAutoEnterCompartment. Make sure the compartment depth right before we
+  // pop is the same as it was right after we pushed.
+  MOZ_ASSERT_IF(mPushedContext, mCompartmentDepthOnEntry ==
+                                js::GetEnterCompartmentDepth(mPushedContext));
+  DebugOnly<JSContext*> stackTop;
+  MOZ_ASSERT(mPushedContext == nsXPConnect::XPConnect()->GetCurrentJSContext());
+  XPCJSRuntime::Get()->GetJSContextStack()->Pop();
+  mScx = nullptr;
+}
+
+bool
+danger::AutoCxPusher::IsStackTop() const
+{
+  uint32_t currentDepth = XPCJSRuntime::Get()->GetJSContextStack()->Count();
+  MOZ_ASSERT(currentDepth >= mStackDepthAfterPush);
+  return currentDepth == mStackDepthAfterPush;
+}
+
 } // namespace dom
 } // namespace mozilla

dom/base/ScriptSettings.h

@@ -9,19 +9,52 @@
 #ifndef mozilla_dom_ScriptSettings_h
 #define mozilla_dom_ScriptSettings_h
 
-#include "nsCxPusher.h"
 #include "MainThreadUtils.h"
 #include "nsIGlobalObject.h"
 #include "nsIPrincipal.h"
 
 #include "mozilla/Maybe.h"
 
+#include "jsapi.h"
+
 class nsPIDOMWindow;
 class nsGlobalWindow;
+class nsIScriptContext;
 
 namespace mozilla {
 namespace dom {
 
+namespace danger {
+
+/**
+ * Fundamental cx pushing class. All other cx pushing classes are implemented
+ * in terms of this class.
+ */
+class MOZ_STACK_CLASS AutoCxPusher
+{
+public:
+  explicit AutoCxPusher(JSContext *aCx, bool aAllowNull = false);
+  ~AutoCxPusher();
+
+  nsIScriptContext* GetScriptContext() { return mScx; }
+
+  // Returns true if this AutoCxPusher performed the push that is currently at
+  // the top of the cx stack.
+  bool IsStackTop() const;
+
+private:
+  mozilla::Maybe<JSAutoRequest> mAutoRequest;
+  mozilla::Maybe<JSAutoCompartment> mAutoCompartment;
+  nsCOMPtr<nsIScriptContext> mScx;
+  uint32_t mStackDepthAfterPush;
+#ifdef DEBUG
+  JSContext* mPushedContext;
+  unsigned mCompartmentDepthOnEntry;
+#endif
+};
+
+} /* namespace danger */
+
 /*
  * System-wide setup/teardown routines. Init and Destroy should be invoked
  * once each, at startup and shutdown (respectively).
@@ -183,7 +216,7 @@ protected:
   AutoJSAPI(nsIGlobalObject* aGlobalObject, bool aIsMainThread, JSContext* aCx);
 
 private:
-  mozilla::Maybe<AutoCxPusher> mCxPusher;
+  mozilla::Maybe<danger::AutoCxPusher> mCxPusher;
   mozilla::Maybe<JSAutoNullableCompartment> mAutoNullableCompartment;
   JSContext *mCx;
 
@@ -241,7 +274,7 @@ class AutoNoJSAPI : protected ScriptSettingsStackEntry {
 public:
   explicit AutoNoJSAPI(bool aIsMainThread = NS_IsMainThread());
 private:
-  mozilla::Maybe<AutoCxPusher> mCxPusher;
+  mozilla::Maybe<danger::AutoCxPusher> mCxPusher;
 };
 
 } // namespace dom

js/xpconnect/src/nsCxPusher.cpp

@@ -15,67 +15,6 @@ using mozilla::DebugOnly;
 
 namespace mozilla {
 
-AutoCxPusher::AutoCxPusher(JSContext* cx, bool allowNull)
-{
-  MOZ_ASSERT_IF(!allowNull, cx);
-
-  // Hold a strong ref to the nsIScriptContext, if any. This ensures that we
-  // only destroy the mContext of an nsJSContext when it is not on the cx stack
-  // (and therefore not in use). See nsJSContext::DestroyJSContext().
-  if (cx)
-    mScx = GetScriptContextFromJSContext(cx);
-
-  XPCJSContextStack *stack = XPCJSRuntime::Get()->GetJSContextStack();
-  if (!stack->Push(cx)) {
-    MOZ_CRASH();
-  }
-  mStackDepthAfterPush = stack->Count();
-
-#ifdef DEBUG
-  mPushedContext = cx;
-  mCompartmentDepthOnEntry = cx ? js::GetEnterCompartmentDepth(cx) : 0;
-#endif
-
-  // Enter a request and a compartment for the duration that the cx is on the
-  // stack if non-null.
-  if (cx) {
-    mAutoRequest.emplace(cx);
-
-    // DOM JSContexts don't store their default compartment object on the cx.
-    JSObject *compartmentObject = mScx ? mScx->GetWindowProxy()
-                                       : js::DefaultObjectForContextOrNull(cx);
-    if (compartmentObject)
-      mAutoCompartment.emplace(cx, compartmentObject);
-  }
-}
-
-AutoCxPusher::~AutoCxPusher()
-{
-  // Leave the compartment and request before popping.
-  mAutoCompartment.reset();
-  mAutoRequest.reset();
-
-  // When we push a context, we may save the frame chain and pretend like we
-  // haven't entered any compartment. This gets restored on Pop(), but we can
-  // run into trouble if a Push/Pop are interleaved with a
-  // JSAutoEnterCompartment. Make sure the compartment depth right before we
-  // pop is the same as it was right after we pushed.
-  MOZ_ASSERT_IF(mPushedContext, mCompartmentDepthOnEntry ==
-                                js::GetEnterCompartmentDepth(mPushedContext));
-  DebugOnly<JSContext*> stackTop;
-  MOZ_ASSERT(mPushedContext == nsXPConnect::XPConnect()->GetCurrentJSContext());
-  XPCJSRuntime::Get()->GetJSContextStack()->Pop();
-  mScx = nullptr;
-}
-
-bool
-AutoCxPusher::IsStackTop() const
-{
-  uint32_t currentDepth = XPCJSRuntime::Get()->GetJSContextStack()->Count();
-  MOZ_ASSERT(currentDepth >= mStackDepthAfterPush);
-  return currentDepth == mStackDepthAfterPush;
-}
-
 AutoJSContext::AutoJSContext(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL)
   : mCx(nullptr)
 {

js/xpconnect/src/nsCxPusher.h

@@ -9,39 +9,13 @@
 
 #include "jsapi.h"
 #include "mozilla/Maybe.h"
+#include "mozilla/dom/ScriptSettings.h"
 #include "nsCOMPtr.h"
 
 class nsIScriptContext;
 
 namespace mozilla {
 
-/**
- * Fundamental cx pushing class. All other cx pushing classes are implemented
- * in terms of this class.
- */
-class MOZ_STACK_CLASS AutoCxPusher
-{
-public:
-  explicit AutoCxPusher(JSContext *aCx, bool aAllowNull = false);
-  ~AutoCxPusher();
-
-  nsIScriptContext* GetScriptContext() { return mScx; }
-
-  // Returns true if this AutoCxPusher performed the push that is currently at
-  // the top of the cx stack.
-  bool IsStackTop() const;
-
-private:
-  mozilla::Maybe<JSAutoRequest> mAutoRequest;
-  mozilla::Maybe<JSAutoCompartment> mAutoCompartment;
-  nsCOMPtr<nsIScriptContext> mScx;
-  uint32_t mStackDepthAfterPush;
-#ifdef DEBUG
-  JSContext* mPushedContext;
-  unsigned mCompartmentDepthOnEntry;
-#endif
-};
-
 /**
  * Use AutoJSContext when you need a JS context on the stack but don't have one
  * passed as a parameter. AutoJSContext will take care of finding the most
@@ -61,7 +35,7 @@ protected:
   void Init(bool aSafe MOZ_GUARD_OBJECT_NOTIFIER_PARAM);
 
   JSContext* mCx;
-  Maybe<AutoCxPusher> mPusher;
+  Maybe<mozilla::dom::danger::AutoCxPusher> mPusher;
   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 

js/xpconnect/src/xpcprivate.h

@@ -2863,7 +2863,7 @@ public:
     { return &mStack; }
 
 private:
-    friend class mozilla::AutoCxPusher;
+    friend class mozilla::dom::danger::AutoCxPusher;
     friend bool xpc::PushJSContextNoScriptContext(JSContext *aCx);;
     friend void xpc::PopJSContextNoScriptContext();