Auto merge of #6183 - ecoal95:webglcontextattributes, r=nox

r? @jdm

I couldn't add the `getContextAttributes` method since `CodegenRust`
doesn't know how to return a dictionary value, I'll take a look at it ASAP.

I think the helper functions can return directly the renderer, since they're used just for that, but I wanted to hear your opinions about this.

By the way I'm interested in adding more serious tests for WebGL, and I think the [khronos conformance suit](https://github.com/KhronosGroup/WebGL/tree/master/conformance-suites/1.0.3) should be the best option.

Should I try to integrate it in wpt, or making a `tests/webgl` directory (or similar) inside the servo tree? (Maybe this question should be for @Ms2ger)

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components/script/dom/bindings/codegen/CodegenRust.py

@@ -1165,6 +1165,15 @@ def getRetvalDeclarationForType(returnType, descriptorProvider):
         return CGGeneric("*mut JSObject")
     if returnType.isSequence():
         raise TypeError("We don't support sequence return values")
+    if returnType.isDictionary():
+        nullable = returnType.nullable()
+        dictName = returnType.inner.name if nullable else returnType.name
+        result = CGGeneric(dictName)
+        if typeNeedsRooting(returnType, descriptorProvider):
+            raise TypeError("We don't support rootable dictionaries return values")
+        if nullable:
+            result = CGWrapper(result, pre="Option<", post=">")
+        return result
 
     raise TypeError("Don't know how to declare return value for %s" %
                     returnType)
@@ -4517,7 +4526,14 @@ class CGDictionary(CGThing):
             conversion = self.getMemberConversion(memberInfo)
             return CGGeneric("%s: %s,\n" % (name, conversion.define()))
 
+        def memberInsert(memberInfo):
+            member, _ = memberInfo
+            name = self.makeMemberName(member.identifier.name)
+            insertion = ("set_dictionary_property(cx, obj, \"%s\", &mut self.%s.to_jsval(cx)).unwrap();" % (name, name))
+            return CGGeneric("%s\n" % insertion)
+
         memberInits = CGList([memberInit(m) for m in self.memberInfo])
+        memberInserts = CGList([memberInsert(m) for m in self.memberInfo])
 
         return string.Template(
             "impl ${selfName} {\n"
@@ -4538,10 +4554,19 @@ class CGDictionary(CGThing):
             "${initMembers}"
             "        })\n"
             "    }\n"
-            "}").substitute({
+            "}\n"
+            "\n"
+            "impl ToJSValConvertible for ${selfName} {\n"
+            "    fn to_jsval(&self, cx: *mut JSContext) -> JSVal {\n"
+            "        let obj = unsafe { JS_NewObject(cx, 0 as *const JSClass, 0 as *const JSObject, 0 as *const JSObject) };\n"
+            "${insertMembers}"
+            "        ObjectOrNullValue(obj)\n"
+            "    }\n"
+            "}\n").substitute({
                 "selfName": self.makeClassName(d),
                 "initParent": CGIndenter(CGGeneric(initParent), indentLevel=12).define(),
                 "initMembers": CGIndenter(memberInits, indentLevel=12).define(),
+                "insertMembers": CGIndenter(memberInserts, indentLevel=8).define(),
                 })
 
     @staticmethod
@@ -4590,6 +4615,7 @@ class CGDictionary(CGThing):
 
         return CGGeneric(conversion)
 
+
     @staticmethod
     def makeIdName(name):
         return name + "_id"
@@ -4750,6 +4776,7 @@ class CGBindingRoot(CGThing):
             'dom::bindings::utils::{Reflectable}',
             'dom::bindings::utils::throwing_constructor',
             'dom::bindings::utils::get_dictionary_property',
+            'dom::bindings::utils::set_dictionary_property',
             'dom::bindings::utils::{NativeProperties, NativePropertyHooks}',
             'dom::bindings::utils::ConstantVal::{IntVal, UintVal}',
             'dom::bindings::utils::NonNullJSNative',

components/script/dom/bindings/utils.rs

@@ -29,7 +29,7 @@ use js::jsapi::{JS_GetClass, JS_LinkConstructorAndPrototype, JS_GetStringCharsAn
 use js::jsapi::JSHandleObject;
 use js::jsapi::JS_GetFunctionObject;
 use js::jsapi::{JS_HasPropertyById, JS_GetPrototype};
-use js::jsapi::{JS_GetProperty, JS_HasProperty};
+use js::jsapi::{JS_GetProperty, JS_HasProperty, JS_SetProperty};
 use js::jsapi::{JS_DefineFunctions, JS_DefineProperty};
 use js::jsapi::{JS_ValueToString, JS_GetReservedSlot, JS_SetReservedSlot};
 use js::jsapi::{JSContext, JSObject, JSBool, jsid, JSClass};
@@ -510,7 +510,6 @@ pub fn is_platform_object(obj: *mut JSObject) -> bool {
 pub fn get_dictionary_property(cx: *mut JSContext,
                                object: *mut JSObject,
                                property: &str) -> Result<Option<JSVal>, ()> {
-    use std::ffi::CString;
     fn has_property(cx: *mut JSContext, object: *mut JSObject, property: &CString,
                     found: &mut JSBool) -> bool {
         unsafe {
@@ -546,6 +545,27 @@ pub fn get_dictionary_property(cx: *mut JSContext,
     Ok(Some(value))
 }
 
+/// Set the property with name `property` from `object`.
+/// Returns `Err(())` on JSAPI failure, or null object,
+/// and Ok(()) otherwise
+pub fn set_dictionary_property(cx: *mut JSContext,
+                               object: *mut JSObject,
+                               property: &str,
+                               value: &mut JSVal) -> Result<(), ()> {
+    if object.is_null() {
+        return Err(());
+    }
+
+    let property = CString::new(property).unwrap();
+    unsafe {
+        if JS_SetProperty(cx, object, property.as_ptr(), value) == 0 {
+            return Err(());
+        }
+    }
+
+    Ok(())
+}
+
 /// Returns whether `proxy` has a property `id` on its prototype.
 pub fn has_property_on_prototype(cx: *mut JSContext, proxy: *mut JSObject,
                                  id: jsid) -> bool {