Implement hiding of interface members via Pref annotations.

8 files changed, 225 insertions, 26 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index ce524583930..a19000ec01e 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -1317,6 +1317,33 @@ def getRetvalDeclarationForType(returnType, descriptorProvider):
                     returnType)
 
 
+class MemberCondition:
+    """
+    An object representing the condition for a member to actually be
+    exposed.  Any of the arguments can be None.  If not
+    None, they should have the following types:
+
+    pref: The name of the preference.
+    func: The name of the function.
+    """
+    def __init__(self, pref=None, func=None):
+        assert pref is None or isinstance(pref, str)
+        assert func is None or isinstance(func, str)
+        self.pref = pref
+
+        def toFuncPtr(val):
+            if val is None:
+                return "None"
+            return "Some(%s)" % val
+        self.func = toFuncPtr(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.
@@ -1340,8 +1367,26 @@ class PropertyDefiner:
         # up used via ResolveProperty or EnumerateProperties.
         return self.generateArray(self.regular, self.variableName())
 
+    @staticmethod
+    def getStringAttr(member, name):
+        attr = member.getExtendedAttribute(name)
+        if attr is None:
+            return None
+        # It's a list of strings
+        assert len(attr) == 1
+        assert attr[0] is not None
+        return attr[0]
+
+    @staticmethod
+    def getControllingCondition(interfaceMember, descriptor):
+        return MemberCondition(
+            PropertyDefiner.getStringAttr(interfaceMember,
+                                          "Pref"),
+            PropertyDefiner.getStringAttr(interfaceMember,
+                                          "Func"))
+
     def generatePrefableArray(self, array, name, specTemplate, specTerminator,
-                              specType, getDataTuple):
+                              specType, getCondition, getDataTuple):
         """
         This method generates our various arrays.
 
@@ -1360,24 +1405,52 @@ class PropertyDefiner:
           returns a tuple suitable for substitution into specTemplate.
         """
 
+        # We generate an all-encompassing list of lists of specs, with each sublist
+        # representing a group of members that share a common pref name. That will
+        # make sure the order of the properties as exposed on the interface and
+        # interface prototype objects does not change when 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) != 0
+        # So we won't put a specTerminator at the very front of the list:
+        lastCondition = getCondition(array[0], self.descriptor)
         specs = []
+        currentSpecs = []
+        prefableSpecs = []
+
+        prefableTemplate = '    Prefable { pref: %s, specs: %s[%d], terminator: %s }'
+
+        def switchToCondition(props, condition):
+            prefableSpecs.append(prefableTemplate %
+                                 ('Some("%s")' % condition.pref if condition.pref else 'None',
+                                  name + "_specs",
+                                  len(specs),
+                                  'true' if specTerminator else 'false'))
+            specs.append("&[\n" + ",\n".join(currentSpecs) + "]\n")
+            del currentSpecs[:]
 
         for member in array:
-            specs.append(specTemplate % getDataTuple(member))
+            curCondition = getCondition(member, self.descriptor)
+            if lastCondition != curCondition:
+                # Terminate previous list
+                if specTerminator:
+                    currentSpecs.append(specTerminator)
+                # And switch to our new pref
+                switchToCondition(self, lastCondition)
+                lastCondition = curCondition
+            # And the actual spec
+            currentSpecs.append(specTemplate % getDataTuple(member))
         if specTerminator:
-            specs.append(specTerminator)
+            currentSpecs.append(specTerminator)
+        switchToCondition(self, lastCondition)
 
-        specsArray = ("const %s_specs: &'static [%s] = &[\n" +
+        specsArray = ("const %s_specs: &'static [&'static[%s]] = &[\n" +
                       ",\n".join(specs) + "\n" +
                       "];\n") % (name, specType)
 
         prefArray = ("const %s: &'static [Prefable<%s>] = &[\n" +
-                     "    Prefable {\n" +
-                     "        pref: None,\n" +
-                     "        specs: &%s_specs,\n" +
-                     "    },\n" +
-                    "];\n") % (name, specType, name)
+                     ",\n".join(prefableSpecs) + "\n" +
+                     "];\n") % (name, specType)
         return specsArray + prefArray
 
 
@@ -1412,14 +1485,17 @@ class MethodDefiner(PropertyDefiner):
             methods = []
         self.regular = [{"name": m.identifier.name,
                          "methodInfo": not m.isStatic(),
-                         "length": methodLength(m)} for m in methods]
+                         "length": methodLength(m),
+                         "condition": PropertyDefiner.getControllingCondition(m, descriptor)}
+                        for m in methods]
 
         # FIXME Check for an existing iterator on the interface first.
         if any(m.isGetter() and m.isIndexed() for m in methods):
             self.regular.append({"name": '@@iterator',
                                  "methodInfo": False,
                                  "selfHostedName": "ArrayValues",
-                                 "length": 0})
+                                 "length": 0,
+                                 "condition": MemberCondition()})
 
         isUnforgeableInterface = bool(descriptor.interface.getExtendedAttribute("Unforgeable"))
         if not static and unforgeable == isUnforgeableInterface:
@@ -1429,6 +1505,7 @@ class MethodDefiner(PropertyDefiner):
                     "name": "toString",
                     "nativeName": stringifier.identifier.name,
                     "length": 0,
+                    "condition": PropertyDefiner.getControllingCondition(stringifier, descriptor)
                 })
         self.unforgeable = unforgeable
 
@@ -1436,6 +1513,9 @@ class MethodDefiner(PropertyDefiner):
         if len(array) == 0:
             return ""
 
+        def condition(m, d):
+            return m["condition"]
+
         flags = "JSPROP_ENUMERATE"
         if self.unforgeable:
             flags += " | JSPROP_PERMANENT | JSPROP_READONLY"
@@ -1483,7 +1563,7 @@ class MethodDefiner(PropertyDefiner):
             '        selfHostedName: 0 as *const libc::c_char\n'
             '    }',
             'JSFunctionSpec',
-            specData)
+            condition, specData)
 
 
 class AttrDefiner(PropertyDefiner):
@@ -1561,7 +1641,7 @@ class AttrDefiner(PropertyDefiner):
             '        setter: JSNativeWrapper { op: None, info: 0 as *const JSJitInfo }\n'
             '    }',
             'JSPropertySpec',
-            specData)
+            PropertyDefiner.getControllingCondition, specData)
 
 
 class ConstDefiner(PropertyDefiner):
@@ -1586,7 +1666,7 @@ class ConstDefiner(PropertyDefiner):
             '    ConstantSpec { name: %s, value: %s }',
             None,
             'ConstantSpec',
-            specData)
+            PropertyDefiner.getControllingCondition, specData)
 
 # We'll want to insert the indent at the beginnings of lines, but we
 # don't want to indent empty lines.  So only indent lines that have a
@@ -2248,8 +2328,8 @@ def InitUnforgeablePropertiesOnHolder(descriptor, properties):
     """
     unforgeables = []
 
-    defineUnforgeableAttrs = "define_properties(cx, unforgeable_holder.handle(), %s_specs).unwrap();"
-    defineUnforgeableMethods = "define_methods(cx, unforgeable_holder.handle(), %s_specs).unwrap();"
+    defineUnforgeableAttrs = "define_prefable_properties(cx, unforgeable_holder.handle(), %s);"
+    defineUnforgeableMethods = "define_prefable_methods(cx, unforgeable_holder.handle(), %s);"
 
     unforgeableMembers = [
         (defineUnforgeableAttrs, properties.unforgeable_attrs),
@@ -5470,6 +5550,7 @@ class CGBindingRoot(CGThing):
             'dom::bindings::interface::{InterfaceConstructorBehavior, NonCallbackInterfaceObjectClass}',
             'dom::bindings::interface::{create_callback_interface_object, create_interface_prototype_object}',
             'dom::bindings::interface::{create_named_constructors, create_noncallback_interface_object}',
+            'dom::bindings::interface::{define_prefable_methods, define_prefable_properties}',
             'dom::bindings::interface::{ConstantSpec, NonNullJSNative}',
             'dom::bindings::interface::ConstantVal::{IntVal, UintVal}',
             'dom::bindings::js::{JS, Root, RootedReference}',
diff --git a/components/script/dom/bindings/interface.rs b/components/script/dom/bindings/interface.rs
index eef2913dabd..54ad8115fda 100644
--- a/components/script/dom/bindings/interface.rs
+++ b/components/script/dom/bindings/interface.rs
@@ -219,7 +219,7 @@ pub unsafe fn create_callback_interface_object(
     rval.set(JS_NewObject(cx, ptr::null()));
     assert!(!rval.ptr.is_null());
     for prefable in constants {
-        define_constants(cx, rval.handle(), prefable.specs);
+        define_constants(cx, rval.handle(), prefable.specs());
     }
     define_name(cx, rval.handle(), name);
     define_on_global_object(cx, receiver, name, rval.handle());
@@ -364,17 +364,31 @@ unsafe fn create_object(
     rval.set(JS_NewObjectWithUniqueType(cx, class, proto));
     assert!(!rval.ptr.is_null());
     if let Some(methods) = methods {
-        for prefable in methods {
-            define_methods(cx, rval.handle(), prefable.specs).unwrap();
-        }
+        define_prefable_methods(cx, rval.handle(), methods);
     }
     if let Some(properties) = properties {
-        for prefable in properties {
-            define_properties(cx, rval.handle(), prefable.specs).unwrap();
-        }
+        define_prefable_properties(cx, rval.handle(), properties);
     }
     for prefable in constants {
-        define_constants(cx, rval.handle(), prefable.specs);
+        define_constants(cx, rval.handle(), prefable.specs());
+    }
+}
+
+/// Conditionally define methods on an object.
+pub unsafe fn define_prefable_methods(cx: *mut JSContext,
+                                      obj: HandleObject,
+                                      methods: &'static [Prefable<JSFunctionSpec>]) {
+    for prefable in methods {
+        define_methods(cx, obj, prefable.specs()).unwrap();
+    }
+}
+
+/// Conditionally define properties on an object.
+pub unsafe fn define_prefable_properties(cx: *mut JSContext,
+                                         obj: HandleObject,
+                                         properties: &'static [Prefable<JSPropertySpec>]) {
+    for prefable in properties {
+        define_properties(cx, obj, prefable.specs()).unwrap();
     }
 }
 
diff --git a/components/script/dom/bindings/utils.rs b/components/script/dom/bindings/utils.rs
index 1e2cf5c40f6..29eb33bdefd 100644
--- a/components/script/dom/bindings/utils.rs
+++ b/components/script/dom/bindings/utils.rs
@@ -41,6 +41,7 @@ use std::os::raw::c_void;
 use std::ptr;
 use std::slice;
 use util::non_geckolib::jsstring_to_str;
+use util::prefs;
 
 /// Proxy handler for a WindowProxy.
 pub struct WindowProxyHandler(pub *const libc::c_void);
@@ -558,8 +559,30 @@ pub const DOM_CALLBACKS: DOMCallbacks = DOMCallbacks {
     instanceClassMatchesProto: Some(instance_class_has_proto_at_depth),
 };
 
-#[allow(missing_docs)]
+/// A container around JS member specifications that are conditionally enabled.
 pub struct Prefable<T: 'static> {
+    /// If present, the name of the preference used to conditionally enable these specs.
     pub pref: Option<&'static str>,
-    pub specs: &'static [T]
+    /// The underlying slice of specifications.
+    pub specs: &'static [T],
+    /// Whether the specifications contain special terminating entries that should be
+    /// included or not.
+    pub terminator: bool,
+}
+
+impl<T> Prefable<T> {
+    /// Retrieve the slice represented by this container, unless the condition
+    /// guarding it is false.
+    pub fn specs(&self) -> &'static [T] {
+        if let Some(pref) = self.pref {
+            if !prefs::get_pref(pref).as_boolean().unwrap_or(false) {
+                return if self.terminator {
+                    &self.specs[self.specs.len() - 1..]
+                } else {
+                    &[]
+                };
+            }
+        }
+        self.specs
+    }
 }
diff --git a/components/script/dom/testbinding.rs b/components/script/dom/testbinding.rs
index f69b844f4ed..04116b29534 100644
--- a/components/script/dom/testbinding.rs
+++ b/components/script/dom/testbinding.rs
@@ -493,10 +493,18 @@ impl TestBindingMethods for TestBinding {
     fn StringMozPreference(&self, pref_name: DOMString) -> DOMString {
         get_pref(pref_name.as_ref()).as_string().map(|s| DOMString::from(s)).unwrap_or_else(|| DOMString::new())
     }
+    fn PrefControlledAttributeDisabled(&self) -> bool { false }
+    fn PrefControlledAttributeEnabled(&self) -> bool { false }
+    fn PrefControlledMethodDisabled(&self) {}
+    fn PrefControlledMethodEnabled(&self) {}
 }
 
 impl TestBinding {
     pub fn BooleanAttributeStatic(_: GlobalRef) -> bool { false }
     pub fn SetBooleanAttributeStatic(_: GlobalRef, _: bool) {}
     pub fn ReceiveVoidStatic(_: GlobalRef) {}
+    pub fn PrefControlledStaticAttributeDisabled(_: GlobalRef) -> bool { false }
+    pub fn PrefControlledStaticAttributeEnabled(_: GlobalRef) -> bool { false }
+    pub fn PrefControlledStaticMethodDisabled(_: GlobalRef) {}
+    pub fn PrefControlledStaticMethodEnabled(_: GlobalRef) {}
 }
diff --git a/components/script/dom/webidls/TestBinding.webidl b/components/script/dom/webidls/TestBinding.webidl
index 4b4265f326a..d0bfbbfef2a 100644
--- a/components/script/dom/webidls/TestBinding.webidl
+++ b/components/script/dom/webidls/TestBinding.webidl
@@ -402,4 +402,26 @@ interface TestBinding {
   static void receiveVoidStatic();
   boolean BooleanMozPreference(DOMString pref_name);
   DOMString StringMozPreference(DOMString pref_name);
+
+  [Pref="dom.testbinding.prefcontrolled.enabled"]
+  readonly attribute boolean prefControlledAttributeDisabled;
+  [Pref="dom.testbinding.prefcontrolled.enabled"]
+  static readonly attribute boolean prefControlledStaticAttributeDisabled;
+  [Pref="dom.testbinding.prefcontrolled.enabled"]
+  void prefControlledMethodDisabled();
+  [Pref="dom.testbinding.prefcontrolled.enabled"]
+  static void prefControlledStaticMethodDisabled();
+  [Pref="dom.testbinding.prefcontrolled.enabled"]
+  const unsigned short prefControlledConstDisabled = 0;
+
+  [Pref="dom.testbinding.prefcontrolled2.enabled"]
+  readonly attribute boolean prefControlledAttributeEnabled;
+  [Pref="dom.testbinding.prefcontrolled2.enabled"]
+  static readonly attribute boolean prefControlledStaticAttributeEnabled;
+  [Pref="dom.testbinding.prefcontrolled2.enabled"]
+  void prefControlledMethodEnabled();
+  [Pref="dom.testbinding.prefcontrolled2.enabled"]
+  static void prefControlledStaticMethodEnabled();
+  [Pref="dom.testbinding.prefcontrolled2.enabled"]
+  const unsigned short prefControlledConstEnabled = 0;
 };
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index b57efe99a79..c89463c0a0c 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -6406,6 +6406,12 @@
             "url": "/_mozilla/mozilla/innerHTML.html"
           }
         ],
+        "mozilla/interface_member_exposed.html": [
+          {
+            "path": "mozilla/interface_member_exposed.html",
+            "url": "/_mozilla/mozilla/interface_member_exposed.html"
+          }
+        ],
         "mozilla/interfaces.html": [
           {
             "path": "mozilla/interfaces.html",
diff --git a/tests/wpt/mozilla/meta/mozilla/interface_member_exposed.html.ini b/tests/wpt/mozilla/meta/mozilla/interface_member_exposed.html.ini
new file mode 100644
index 00000000000..19543bd7a73
--- /dev/null
+++ b/tests/wpt/mozilla/meta/mozilla/interface_member_exposed.html.ini
@@ -0,0 +1,4 @@
+[interface_member_exposed.html]
+  type: testharness
+  prefs: [dom.testbinding.enabled:true,
+          dom.testbinding.prefcontrolled2.enabled:true]
diff --git a/tests/wpt/mozilla/tests/mozilla/interface_member_exposed.html b/tests/wpt/mozilla/tests/mozilla/interface_member_exposed.html
new file mode 100644
index 00000000000..d455e8e5586
--- /dev/null
+++ b/tests/wpt/mozilla/tests/mozilla/interface_member_exposed.html
@@ -0,0 +1,41 @@
+<!doctype html>
+<meta charset="utf-8">
+<title></title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+function test_member(name, enabled, target) {
+  var status = enabled ? "Enabled" : "Disabled";
+  var verb = enabled ? "shows" : "hides";
+  test(function() {
+    var interface = target(window.TestBinding);
+    var descriptor = Object.getOwnPropertyDescriptor(interface, name);
+    if (enabled) {
+      assert_not_equals(descriptor, undefined);
+    } else {
+      assert_equals(descriptor, undefined);
+    }
+  }, status + " preference " + verb + " member controlled by that preference: " + name);
+}
+
+var members = [
+  'prefControlledAttribute',
+  'prefControlledMethod'
+];
+var staticMembers = [
+  'prefControlledStaticAttribute',
+  'prefControlledStaticMethod',
+  'prefControlledConst'
+];
+
+for (var i = 0; i < members.length; i++) {
+  var name = members[i];
+  test_member(name + 'Enabled', true, function(o) { return Object.getPrototypeOf(new o()) });
+  test_member(name + 'Disabled', false, function(o) { return Object.getPrototypeOf(new o()) });
+}
+for (var i = 0; i < staticMembers.length; i++) {
+  var name = staticMembers[i];
+  test_member(name + 'Enabled', true, function(o) { return o; });
+  test_member(name + 'Disabled', false, function(o) { return o; });
+}
+</script>