Bug 1299306 part 1. Refactor the error handling in CGWrapNonWrapperCacheMethod and CGWrapWithCacheMethod to have less duplication. r=peterv

dom/bindings/Codegen.py

@@ -3402,7 +3402,7 @@ def InitUnforgeablePropertiesOnHolder(descriptor, properties, failureCode,
     return CGWrapper(CGList(unforgeables), pre="\n")
 
 
-def CopyUnforgeablePropertiesToInstance(descriptor, wrapperCache):
+def CopyUnforgeablePropertiesToInstance(descriptor, failureCode):
     """
     Copy the unforgeable properties from the unforgeable holder for
     this interface to the instance object we have.
@@ -3422,15 +3422,6 @@ def CopyUnforgeablePropertiesToInstance(descriptor, wrapperCache):
             """))
     ]
 
-    if wrapperCache:
-        cleanup = dedent(
-            """
-            aCache->ReleaseWrapper(aObject);
-            aCache->ClearWrapper();
-            """)
-    else:
-        cleanup = ""
-
     # For proxies, we want to define on the expando object, not directly on the
     # reflector, so we can make sure we don't get confused by named getters.
     if descriptor.proxy:
@@ -3439,11 +3430,10 @@ def CopyUnforgeablePropertiesToInstance(descriptor, wrapperCache):
             JS::Rooted<JSObject*> expando(aCx,
               DOMProxyHandler::EnsureExpandoObject(aCx, aReflector));
             if (!expando) {
-              $*{cleanup}
-              return false;
+              $*{failureCode}
             }
             """,
-            cleanup=cleanup)))
+            failureCode=failureCode)))
         obj = "expando"
     else:
         obj = "aReflector"
@@ -3453,12 +3443,11 @@ def CopyUnforgeablePropertiesToInstance(descriptor, wrapperCache):
         JS::Rooted<JSObject*> unforgeableHolder(aCx,
           &js::GetReservedSlot(canonicalProto, DOM_INTERFACE_PROTO_SLOTS_BASE).toObject());
         if (!JS_InitializePropertiesFromCompatibleNativeObject(aCx, ${obj}, unforgeableHolder)) {
-          $*{cleanup}
-          return false;
+          $*{failureCode}
         }
         """,
         obj=obj,
-        cleanup=cleanup)))
+        failureCode=failureCode)))
 
     return CGWrapper(CGList(copyCode), pre="\n").define()
 
@@ -3478,7 +3467,7 @@ def AssertInheritanceChain(descriptor):
     return asserts
 
 
-def InitMemberSlots(descriptor, wrapperCache):
+def InitMemberSlots(descriptor, failureCode):
     """
     Initialize member slots on our JS object if we're supposed to have some.
 
@@ -3489,22 +3478,13 @@ def InitMemberSlots(descriptor, wrapperCache):
     """
     if not descriptor.interface.hasMembersInSlots():
         return ""
-    if wrapperCache:
-        clearWrapper = dedent(
-            """
-            aCache->ReleaseWrapper(aObject);
-            aCache->ClearWrapper();
-            """)
-    else:
-        clearWrapper = ""
     return fill(
         """
         if (!UpdateMemberSlots(aCx, aReflector, aObject)) {
-          $*{clearWrapper}
-          return false;
+          $*{failureCode}
         }
         """,
-        clearWrapper=clearWrapper)
+        failureCode=failureCode)
 
 
 def DeclareProto():
@@ -3561,6 +3541,14 @@ class CGWrapWithCacheMethod(CGAbstractMethod):
                 """)
         else:
             preserveWrapper = "PreserveWrapper(aObject);\n"
+
+        failureCode = dedent(
+            """
+            aCache->ReleaseWrapper(aObject);
+            aCache->ClearWrapper();
+            return false;
+            """)
+
         return fill(
             """
             $*{assertInheritance}
@@ -3615,8 +3603,9 @@ class CGWrapWithCacheMethod(CGAbstractMethod):
             assertInheritance=AssertInheritanceChain(self.descriptor),
             declareProto=DeclareProto(),
             createObject=CreateBindingJSObject(self.descriptor, self.properties),
-            unforgeable=CopyUnforgeablePropertiesToInstance(self.descriptor, True),
-            slots=InitMemberSlots(self.descriptor, True),
+            unforgeable=CopyUnforgeablePropertiesToInstance(self.descriptor,
+                                                            failureCode),
+            slots=InitMemberSlots(self.descriptor, failureCode),
             preserveWrapper=preserveWrapper)
 
 
@@ -3655,6 +3644,8 @@ class CGWrapNonWrapperCacheMethod(CGAbstractMethod):
         self.properties = properties
 
     def definition_body(self):
+        failureCode = "return false;\n"
+
         return fill(
             """
             $*{assertions}
@@ -3673,8 +3664,9 @@ class CGWrapNonWrapperCacheMethod(CGAbstractMethod):
             assertions=AssertInheritanceChain(self.descriptor),
             declareProto=DeclareProto(),
             createObject=CreateBindingJSObject(self.descriptor, self.properties),
-            unforgeable=CopyUnforgeablePropertiesToInstance(self.descriptor, False),
-            slots=InitMemberSlots(self.descriptor, False))
+            unforgeable=CopyUnforgeablePropertiesToInstance(self.descriptor,
+                                                            failureCode),
+            slots=InitMemberSlots(self.descriptor, failureCode))
 
 
 class CGWrapGlobalMethod(CGAbstractMethod):
@@ -3757,7 +3749,7 @@ class CGWrapGlobalMethod(CGAbstractMethod):
             chromeProperties=chromeProperties,
             failureCode=failureCode,
             unforgeable=unforgeable,
-            slots=InitMemberSlots(self.descriptor, True))
+            slots=InitMemberSlots(self.descriptor, failureCode))
 
 
 class CGUpdateMemberSlotsMethod(CGAbstractStaticMethod):