Bug 1395421 part 2. When a get() happens on a JS-implemented maplike, notify the JS implementation so it can take some sort of action (e.g. logging or warning). r=peterv

MozReview-Commit-ID: 9G115wOyzvm

dom/bindings/Codegen.py

@@ -15570,6 +15570,17 @@ class CGJSImplClass(CGBindingImplClass):
                         static=True,
                         body=self.getCreateFromExistingBody()))
 
+        if (descriptor.interface.isJSImplemented() and
+            descriptor.interface.maplikeOrSetlikeOrIterable and
+            descriptor.interface.maplikeOrSetlikeOrIterable.isMaplike()):
+            self.methodDecls.append(
+                ClassMethod("__OnGet",
+                            "void",
+                            [Argument("JS::Handle<JS::Value>", "aKey"),
+                             Argument("JS::Handle<JS::Value>", "aValue"),
+                             Argument("ErrorResult&", "aRv")],
+                            body="mImpl->__OnGet(aKey, aValue, aRv);\n"))
+
         CGClass.__init__(self, descriptor.name,
                          bases=baseClasses,
                          constructors=[constructor],
@@ -15931,16 +15942,31 @@ class CGCallbackInterface(CGCallback):
                         not iface.isJSImplemented()))]
         methods = [CallbackOperation(m, sig, descriptor, spiderMonkeyInterfacesAreStructs)
                    for m in methods for sig in m.signatures()]
+
+        needInitId = False
         if iface.isJSImplemented() and iface.ctor():
             sigs = descriptor.interface.ctor().signatures()
             if len(sigs) != 1:
                 raise TypeError("We only handle one constructor.  See bug 869268.")
             methods.append(CGJSImplInitOperation(sigs[0], descriptor))
-        if any(m.isAttr() or m.isMethod() for m in iface.members) or (iface.isJSImplemented() and iface.ctor()):
-            methods.append(initIdsClassMethod([descriptor.binaryNameFor(m.identifier.name)
-                                               for m in iface.members
-                                               if m.isAttr() or m.isMethod()] +
-                                              (["__init"] if iface.isJSImplemented() and iface.ctor() else []),
+            needInitId = True
+
+        needOnGetId = False
+        if (iface.isJSImplemented() and
+            iface.maplikeOrSetlikeOrIterable and
+            iface.maplikeOrSetlikeOrIterable.isMaplike()):
+            methods.append(CGJSImplOnGetOperation(descriptor))
+            needOnGetId = True
+
+        idlist = [descriptor.binaryNameFor(m.identifier.name)
+                  for m in iface.members
+                  if m.isAttr() or m.isMethod()]
+        if needInitId:
+            idlist.append("__init")
+        if needOnGetId:
+            idlist.append("__onget")
+        if len(idlist) != 0:
+            methods.append(initIdsClassMethod(idlist,
                                               iface.identifier.name + "Atoms"))
         CGCallback.__init__(self, iface, descriptor, "CallbackInterface",
                             methods, getters=getters, setters=setters)
@@ -16459,6 +16485,32 @@ class CGJSImplInitOperation(CallbackOperationBase):
         return "__init"
 
 
+class CGJSImplOnGetOperation(CallbackOperationBase):
+    """
+    Codegen the __OnGet() method used to notify the JS impl that a get() is
+    happening on a JS-implemented maplike.  This method takes two arguments
+    (key and value) and returns nothing.
+    """
+    def __init__(self, descriptor):
+        CallbackOperationBase.__init__(
+            self,
+            (BuiltinTypes[IDLBuiltinType.Types.void],
+             [FakeArgument(BuiltinTypes[IDLBuiltinType.Types.any],
+                           None,
+                           "key"),
+              FakeArgument(BuiltinTypes[IDLBuiltinType.Types.any],
+                           None,
+                           "value")]),
+            "__onget", "__OnGet",
+            descriptor,
+            singleOperation=False,
+            rethrowContentException=True,
+            spiderMonkeyInterfacesAreStructs=True)
+
+    def getPrettyName(self):
+        return "__onget"
+
+
 def getMaplikeOrSetlikeErrorReturn(helperImpl):
     """
     Generate return values based on whether a maplike or setlike generated
@@ -16741,7 +16793,21 @@ class CGMaplikeOrSetlikeMethodGenerator(CGThing):
             JS::Rooted<JS::Value> result(cx);
             """))]
         arguments = ["&result"]
-        return self.mergeTuples(r, (code, arguments, []))
+        if self.descriptor.interface.isJSImplemented():
+            callOnGet = [CGGeneric(dedent(
+                """
+                {
+                  JS::ExposeValueToActiveJS(result);
+                  ErrorResult onGetResult;
+                  self->__OnGet(arg0Val, result, onGetResult);
+                  if (onGetResult.MaybeSetPendingException(cx)) {
+                    return false;
+                  }
+                }
+                """))]
+        else:
+            callOnGet = []
+        return self.mergeTuples(r, (code, arguments, callOnGet))
 
     def has(self):
         """
@@ -17041,6 +17107,11 @@ class GlobalGenRoots():
             if d.interface.isJSImplemented() and d.interface.ctor():
                 # We'll have an __init() method.
                 members.append(FakeMember('__init'))
+            if (d.interface.isJSImplemented() and
+                d.interface.maplikeOrSetlikeOrIterable and
+                d.interface.maplikeOrSetlikeOrIterable.isMaplike()):
+                # We'll have an __onget() method.
+                members.append(FakeMember('__onget'))
             if len(members) == 0:
                 continue
 

dom/bindings/test/TestInterfaceJSMaplike.js

@@ -32,7 +32,11 @@ TestInterfaceJSMaplike.prototype = {
 
   clearInternal: function() {
     return this.__DOM_IMPL__.__clear();
-  }
+  },
+
+  __onget: function(key, value) {
+    /* no-op */
+  },
 };
 
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([TestInterfaceJSMaplike])

dom/media/PeerConnection.js

@@ -327,6 +327,10 @@ class RTCStatsReport {
   }
 
   get mozPcid() { return this._pcid; }
+
+  __onget(key, value) {
+    /* Do whatever here */
+  }
 }
 setupPrototype(RTCStatsReport, {
   classID: PC_STATS_CID,