Bug 838691 part 2. Add codegen support for calling a function to determine whether a property should be exposed in a WebIDL binding. r=peterv

dom/bindings/Codegen.py

@@ -999,6 +999,27 @@ class CGClassHasInstanceHook(CGAbstractStaticMethod):
 def isChromeOnly(m):
     return m.getExtendedAttribute("ChromeOnly")
 
+class MemberCondition:
+    """
+    An object representing the condition for a member to actually be
+    exposed.  Either pref or func or both can be None.  If not None,
+    they should be strings that have the pref name or function name.
+    """
+    def __init__(self, pref, func):
+        assert pref is None or isinstance(pref, str)
+        assert func is None or isinstance(func, str)
+        self.pref = pref
+        if func is None:
+            self.func = "nullptr"
+        else:
+            self.func = "&" + func
+
+    def __eq__(self, other):
+        return self.pref == other.pref and self.func == other.func
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
 class PropertyDefiner:
     """
     A common superclass for defining things on prototype objects.
@@ -1042,17 +1063,24 @@ class PropertyDefiner:
         return str
 
     @staticmethod
-    def getControllingPref(interfaceMember):
+    def getStringAttr(member, name):
-        prefName = interfaceMember.getExtendedAttribute("Pref")
+        attr = member.getExtendedAttribute(name)
-        if prefName is None:
+        if attr is None:
             return None
         # It's a list of strings
-        assert(len(prefName) is 1)
+        assert(len(attr) is 1)
-        assert(prefName[0] is not None)
+        assert(attr[0] is not None)
-        return prefName[0]
+        return attr[0]
+
+    @staticmethod
+    def getControllingCondition(interfaceMember):
+        return MemberCondition(PropertyDefiner.getStringAttr(interfaceMember,
+                                                             "Pref"),
+                               PropertyDefiner.getStringAttr(interfaceMember,
+                                                             "Func"))
 
     def generatePrefableArray(self, array, name, specTemplate, specTerminator,
-                              specType, getPref, getDataTuple, doIdArrays):
+                              specType, getCondition, getDataTuple, doIdArrays):
         """
         This method generates our various arrays.
 
@@ -1067,8 +1095,8 @@ class PropertyDefiner:
 
         specType is the actual typename of our spec
 
-        getPref is a callback function that takes an array entry and returns
+        getCondition is a callback function that takes an array entry and
-          the corresponding pref value.
+          returns the corresponding MemberCondition.
 
         getDataTuple is a callback function that takes an array entry and
           returns a tuple suitable for substitution into specTemplate.
@@ -1081,34 +1109,35 @@ class PropertyDefiner:
         # pref control is added to members while still allowing us to define all
         # the members in the smallest number of JSAPI calls.
         assert(len(array) is not 0)
-        lastPref = getPref(array[0]) # So we won't put a specTerminator
+        lastCondition = getCondition(array[0]) # So we won't put a specTerminator
-                                     # at the very front of the list.
+                                               # at the very front of the list.
         specs = []
         prefableSpecs = []
 
-        prefableTemplate = '  { true, nullptr, &%s[%d] }'
+        prefableTemplate = '  { true, %s, &%s[%d] }'
         prefCacheTemplate = '&%s[%d].enabled'
-        def switchToPref(props, pref):
+        def switchToCondition(props, condition):
             # Remember the info about where our pref-controlled
             # booleans live.
-            if pref is not None:
+            if condition.pref is not None:
                 props.prefCacheData.append(
-                    (pref, prefCacheTemplate % (name, len(prefableSpecs)))
+                    (condition.pref,
+                     prefCacheTemplate % (name, len(prefableSpecs)))
                     )
             # Set up pointers to the new sets of specs inside prefableSpecs
             prefableSpecs.append(prefableTemplate %
-                                 (name + "_specs", len(specs)))
+                                 (condition.func, name + "_specs", len(specs)))
 
-        switchToPref(self, lastPref)
+        switchToCondition(self, lastCondition)
 
         for member in array:
-            curPref = getPref(member)
+            curCondition = getCondition(member)
-            if lastPref != curPref:
+            if lastCondition != curCondition:
                 # Terminate previous list
                 specs.append(specTerminator)
                 # And switch to our new pref
-                switchToPref(self, curPref)
+                switchToCondition(self, curCondition)
-                lastPref = curPref
+                lastCondition = curCondition
             # And the actual spec
             specs.append(specTemplate % getDataTuple(member))
         specs.append(specTerminator)
@@ -1162,7 +1191,7 @@ class MethodDefiner(PropertyDefiner):
                        "methodInfo": not m.isStatic(),
                        "length": methodLength(m),
                        "flags": "JSPROP_ENUMERATE",
-                       "pref": PropertyDefiner.getControllingPref(m) }
+                       "condition": PropertyDefiner.getControllingCondition(m) }
             if isChromeOnly(m):
                 self.chrome.append(method)
             else:
@@ -1175,7 +1204,7 @@ class MethodDefiner(PropertyDefiner):
                                  "nativeName": "JS_ArrayIterator",
                                  "length": 0,
                                  "flags": "JSPROP_ENUMERATE",
-                                 "pref": None })
+                                 "condition": MemberCondition(None, None) })
 
         if (not descriptor.interface.parent and not static and
             descriptor.nativeOwnership == 'nsisupports' and
@@ -1184,7 +1213,7 @@ class MethodDefiner(PropertyDefiner):
                                 "methodInfo": False,
                                 "length": 1,
                                 "flags": "0",
-                                "pref": None })
+                                "condition": MemberCondition(None, None) })
 
         if not static:
             stringifier = descriptor.operations['Stringifier']
@@ -1193,7 +1222,7 @@ class MethodDefiner(PropertyDefiner):
                                  "nativeName": stringifier.identifier.name,
                                  "length": 0,
                                  "flags": "JSPROP_ENUMERATE",
-                                 "pref": PropertyDefiner.getControllingPref(stringifier) }
+                                 "condition": PropertyDefiner.getControllingCondition(stringifier) }
                 if isChromeOnly(stringifier):
                     self.chrome.append(toStringDesc)
                 else:
@@ -1212,8 +1241,8 @@ class MethodDefiner(PropertyDefiner):
         if len(array) == 0:
             return ""
 
-        def pref(m):
+        def condition(m):
-            return m["pref"]
+            return m["condition"]
 
         def specData(m):
             accessor = m.get("nativeName", m["name"])
@@ -1229,7 +1258,7 @@ class MethodDefiner(PropertyDefiner):
             '  JS_FNINFO("%s", %s, %s, %s, %s)',
             '  JS_FS_END',
             'JSFunctionSpec',
-            pref, specData, doIdArrays)
+            condition, specData, doIdArrays)
 
 class AttrDefiner(PropertyDefiner):
     def __init__(self, descriptor, name, static, unforgeable=False):
@@ -1304,7 +1333,7 @@ class AttrDefiner(PropertyDefiner):
             '  { "%s", 0, %s, %s, %s}',
             '  { 0, 0, 0, JSOP_NULLWRAPPER, JSOP_NULLWRAPPER }',
             'JSPropertySpec',
-            PropertyDefiner.getControllingPref, specData, doIdArrays)
+            PropertyDefiner.getControllingCondition, specData, doIdArrays)
 
 class ConstDefiner(PropertyDefiner):
     """
@@ -1330,7 +1359,7 @@ class ConstDefiner(PropertyDefiner):
             '  { "%s", %s }',
             '  { 0, JSVAL_VOID }',
             'ConstantSpec',
-            PropertyDefiner.getControllingPref, specData, doIdArrays)
+            PropertyDefiner.getControllingCondition, specData, doIdArrays)
 
 class PropertyArrays():
     def __init__(self, descriptor):