Auto merge of #23844 - saschanaz:tojson, r=Manishearth

Support default toJSON in WebIDL

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Ported related lines from gecko.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #22781

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- [x] There are tests for these changes

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9 files changed, 99 insertions, 158 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 4bea65388b6..93856508e6e 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -2881,6 +2881,42 @@ class PropertyArrays():
         return define
 
 
+class CGCollectJSONAttributesMethod(CGAbstractMethod):
+    """
+    Generate the CollectJSONAttributes method for an interface descriptor
+    """
+    def __init__(self, descriptor, toJSONMethod):
+        args = [Argument('SafeJSContext', 'cx'),
+                Argument('HandleObject', 'obj'),
+                Argument('*const %s' % descriptor.concreteType, 'this'),
+                Argument('&RootedGuard<*mut JSObject>', 'result')]
+        CGAbstractMethod.__init__(self, descriptor, 'CollectJSONAttributes',
+                                  'bool', args, pub=True, unsafe=True)
+        self.toJSONMethod = toJSONMethod
+
+    def definition_body(self):
+        ret = ''
+        interface = self.descriptor.interface
+        for m in interface.members:
+            if m.isAttr() and not m.isStatic() and m.type.isJSONType():
+                name = m.identifier.name
+                ret += fill(
+                    """
+                    rooted!(in(*cx) let mut temp = UndefinedValue());
+                    if !get_${name}(cx, obj, this, JSJitGetterCallArgs { _base: temp.handle_mut().into() }) {
+                      return false;
+                    }
+                    if !JS_DefineProperty(*cx, result.handle().into(),
+                                          ${nameAsArray} as *const u8 as *const libc::c_char,
+                                          temp.handle(), JSPROP_ENUMERATE as u32) {
+                      return false;
+                    }
+                    """,
+                    name=name, nameAsArray=str_to_const_array(name))
+        ret += 'return true;\n'
+        return CGGeneric(ret)
+
+
 class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
     """
     Generate the CreateInterfaceObjects method for an interface descriptor.
@@ -3619,6 +3655,42 @@ class CGSpecializedMethod(CGAbstractExternMethod):
         return MakeNativeName(nativeName)
 
 
+class CGDefaultToJSONMethod(CGSpecializedMethod):
+    def __init__(self, descriptor, method):
+        assert method.isDefaultToJSON()
+        CGSpecializedMethod.__init__(self, descriptor, method)
+
+    def definition_body(self):
+        ret = dedent("""
+            rooted!(in(*cx) let result = JS_NewPlainObject(*cx));
+            if result.is_null() {
+              return false;
+            }
+            """)
+
+        jsonDescriptors = [self.descriptor]
+        interface = self.descriptor.interface.parent
+        while interface:
+            descriptor = self.descriptor.getDescriptor(interface.identifier.name)
+            if descriptor.hasDefaultToJSON:
+                jsonDescriptors.append(descriptor)
+            interface = interface.parent
+
+        form = """
+             if !${parentclass}CollectJSONAttributes(cx, _obj, this, &result) {
+                 return false;
+             }
+             """
+
+        # Iterate the array in reverse: oldest ancestor first
+        for descriptor in jsonDescriptors[:0:-1]:
+            ret += fill(form, parentclass=toBindingNamespace(descriptor.name) + "::")
+        ret += fill(form, parentclass="")
+        ret += ('(*args).rval().set(ObjectValue(*result));\n'
+                'return true;\n')
+        return CGGeneric(ret)
+
+
 class CGStaticMethod(CGAbstractStaticBindingMethod):
     """
     A class for generating the Rust code for an IDL static method.
@@ -5665,7 +5737,8 @@ class CGInterfaceTrait(CGThing):
             for m in descriptor.interface.members:
                 if (m.isMethod() and not m.isStatic() and
                         not m.isMaplikeOrSetlikeOrIterableMethod() and
-                        (not m.isIdentifierLess() or m.isStringifier())):
+                        (not m.isIdentifierLess() or m.isStringifier()) and
+                        not m.isDefaultToJSON()):
                     name = CGSpecializedMethod.makeNativeName(descriptor, m)
                     infallible = 'infallible' in descriptor.getExtendedAttributes(m)
                     for idx, (rettype, arguments) in enumerate(m.signatures()):
@@ -5856,7 +5929,9 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'js::jsapi::JS_HasProperty',
         'js::jsapi::JS_HasPropertyById',
         'js::rust::wrappers::JS_InitializePropertiesFromCompatibleNativeObject',
+        'js::jsapi::JS_NewPlainObject',
         'js::jsapi::JS_NewObject',
+        'js::rust::RootedGuard',
         'js::rust::wrappers::JS_NewObjectWithGivenProto',
         'js::rust::wrappers::JS_NewObjectWithoutMetadata',
         'js::rust::wrappers::ObjectIsDate',
@@ -6055,6 +6130,7 @@ class CGDescriptor(CGThing):
 
         cgThings = []
 
+        defaultToJSONMethod = None
         unscopableNames = []
         for m in descriptor.interface.members:
             if (m.isMethod() and
@@ -6062,7 +6138,9 @@ class CGDescriptor(CGThing):
                 if m.getExtendedAttribute("Unscopable"):
                     assert not m.isStatic()
                     unscopableNames.append(m.identifier.name)
-                if m.isStatic():
+                if m.isDefaultToJSON():
+                    defaultToJSONMethod = m
+                elif m.isStatic():
                     assert descriptor.interface.hasInterfaceObject()
                     cgThings.append(CGStaticMethod(descriptor, m))
                 elif not descriptor.interface.isCallback():
@@ -6096,6 +6174,10 @@ class CGDescriptor(CGThing):
                 if (not m.isStatic() and not descriptor.interface.isCallback()):
                     cgThings.append(CGMemberJITInfo(descriptor, m))
 
+        if defaultToJSONMethod:
+            cgThings.append(CGDefaultToJSONMethod(descriptor, defaultToJSONMethod))
+            cgThings.append(CGMemberJITInfo(descriptor, defaultToJSONMethod))
+
         if descriptor.concrete:
             cgThings.append(CGClassFinalizeHook(descriptor))
             cgThings.append(CGClassTraceHook(descriptor))
@@ -6113,6 +6195,9 @@ class CGDescriptor(CGThing):
 
         properties = PropertyArrays(descriptor)
 
+        if defaultToJSONMethod:
+            cgThings.append(CGCollectJSONAttributesMethod(descriptor, defaultToJSONMethod))
+
         if descriptor.concrete:
             if descriptor.proxy:
                 # cgThings.append(CGProxyIsProxy(descriptor))
diff --git a/components/script/dom/bindings/codegen/Configuration.py b/components/script/dom/bindings/codegen/Configuration.py
index 81f61a648f1..bde6e71bcfb 100644
--- a/components/script/dom/bindings/codegen/Configuration.py
+++ b/components/script/dom/bindings/codegen/Configuration.py
@@ -250,6 +250,8 @@ class Descriptor(DescriptorProvider):
             'Stringifier': None,
         }
 
+        self.hasDefaultToJSON = False
+
         def addOperation(operation, m):
             if not self.operations[operation]:
                 self.operations[operation] = m
@@ -259,6 +261,8 @@ class Descriptor(DescriptorProvider):
         for m in self.interface.members:
             if m.isMethod() and m.isStringifier():
                 addOperation('Stringifier', m)
+            if m.isMethod() and m.isDefaultToJSON():
+                self.hasDefaultToJSON = True
 
         if self.concrete:
             iface = self.interface
diff --git a/components/script/dom/rtcsessiondescription.rs b/components/script/dom/rtcsessiondescription.rs
index 9aa46f56060..0ef79a321c6 100644
--- a/components/script/dom/rtcsessiondescription.rs
+++ b/components/script/dom/rtcsessiondescription.rs
@@ -14,12 +14,7 @@ use crate::dom::bindings::root::DomRoot;
 use crate::dom::bindings::str::DOMString;
 use crate::dom::globalscope::GlobalScope;
 use crate::dom::window::Window;
-use crate::script_runtime::JSContext;
 use dom_struct::dom_struct;
-use js::conversions::ToJSValConvertible;
-use js::jsapi::JSObject;
-use js::jsval::UndefinedValue;
-use std::ptr::NonNull;
 
 #[dom_struct]
 pub struct RTCSessionDescription {
@@ -71,18 +66,4 @@ impl RTCSessionDescriptionMethods for RTCSessionDescription {
     fn Sdp(&self) -> DOMString {
         self.sdp.clone()
     }
-
-    #[allow(unsafe_code)]
-    /// https://w3c.github.io/webrtc-pc/#dom-rtcsessiondescription-tojson
-    fn ToJSON(&self, cx: JSContext) -> NonNull<JSObject> {
-        let init = RTCSessionDescriptionInit {
-            type_: self.ty,
-            sdp: self.sdp.clone(),
-        };
-        unsafe {
-            rooted!(in(*cx) let mut jsval = UndefinedValue());
-            init.to_jsval(*cx, jsval.handle_mut());
-            NonNull::new(jsval.to_object()).unwrap()
-        }
-    }
 }
diff --git a/components/script/dom/webidls/DOMMatrixReadOnly.webidl b/components/script/dom/webidls/DOMMatrixReadOnly.webidl
index ea5d8caf8e5..317c2860707 100644
--- a/components/script/dom/webidls/DOMMatrixReadOnly.webidl
+++ b/components/script/dom/webidls/DOMMatrixReadOnly.webidl
@@ -81,7 +81,6 @@ interface DOMMatrixReadOnly {
     DOMPoint            transformPoint(optional DOMPointInit point = {});
     Float32Array        toFloat32Array();
     Float64Array        toFloat64Array();
-//                      stringifier;
-//                      serializer = { attribute };
-
+//    [Exposed=Window] stringifier;
+    [Default] object toJSON();
 };
diff --git a/components/script/dom/webidls/DOMPointReadOnly.webidl b/components/script/dom/webidls/DOMPointReadOnly.webidl
index 23643179333..071252c7690 100644
--- a/components/script/dom/webidls/DOMPointReadOnly.webidl
+++ b/components/script/dom/webidls/DOMPointReadOnly.webidl
@@ -20,4 +20,6 @@ interface DOMPointReadOnly {
     readonly attribute unrestricted double y;
     readonly attribute unrestricted double z;
     readonly attribute unrestricted double w;
+
+    [Default] object toJSON();
 };
diff --git a/components/script/dom/webidls/DOMQuad.webidl b/components/script/dom/webidls/DOMQuad.webidl
index 8711dd44215..15f126cfea6 100644
--- a/components/script/dom/webidls/DOMQuad.webidl
+++ b/components/script/dom/webidls/DOMQuad.webidl
@@ -22,6 +22,8 @@ interface DOMQuad {
     [SameObject] readonly attribute DOMPoint p3;
     [SameObject] readonly attribute DOMPoint p4;
     [NewObject] DOMRect getBounds();
+
+    [Default] object toJSON();
 };
 
 dictionary DOMQuadInit {
diff --git a/components/script/dom/webidls/DOMRectReadOnly.webidl b/components/script/dom/webidls/DOMRectReadOnly.webidl
index 9464561bef4..58a8c87cd1c 100644
--- a/components/script/dom/webidls/DOMRectReadOnly.webidl
+++ b/components/script/dom/webidls/DOMRectReadOnly.webidl
@@ -17,6 +17,8 @@ interface DOMRectReadOnly {
   readonly attribute unrestricted double right;
   readonly attribute unrestricted double bottom;
   readonly attribute unrestricted double left;
+
+  [Default] object toJSON();
 };
 
 // https://drafts.fxtf.org/geometry/#dictdef-domrectinit
diff --git a/tests/wpt/metadata/css/geometry/interfaces.html.ini b/tests/wpt/metadata/css/geometry/interfaces.html.ini
index 67e7bfc4757..90a08304978 100644
--- a/tests/wpt/metadata/css/geometry/interfaces.html.ini
+++ b/tests/wpt/metadata/css/geometry/interfaces.html.ini
@@ -282,36 +282,6 @@
   [DOMMatrix interface: calling setMatrixValue(DOMString) on DOMMatrix.fromMatrix({is2D: false}) with too few arguments must throw TypeError]
     expected: FAIL
 
-  [DOMPointReadOnly interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMPointReadOnly interface: new DOMPointReadOnly() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMPointReadOnly]
-    expected: FAIL
-
-  [DOMPointReadOnly interface: new DOMPoint() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMPoint]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: new DOMRectReadOnly() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMRectReadOnly]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: new DOMRect() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMRect]
-    expected: FAIL
-
   [DOMRectList interface: existence and properties of interface object]
     expected: FAIL
 
@@ -339,42 +309,5 @@
   [DOMRectList must be primary interface of [object DOMRect\]]
     expected: FAIL
 
-  [DOMQuad interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMQuad interface: new DOMQuad() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMQuad]
-    expected: FAIL
-
-  [DOMMatrixReadOnly interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMMatrixReadOnly interface: new DOMMatrixReadOnly() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMMatrixReadOnly]
-    expected: FAIL
-
   [Geometry APIs interface IDL tests]
     expected: FAIL
-
-  [DOMPointReadOnly interface: default toJSON operation on new DOMPoint()]
-    expected: FAIL
-
-  [DOMPointReadOnly interface: default toJSON operation on new DOMPointReadOnly()]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: default toJSON operation on new DOMRect()]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: default toJSON operation on new DOMRectReadOnly()]
-    expected: FAIL
-
-  [DOMQuad interface: default toJSON operation on new DOMQuad()]
-    expected: FAIL
-
-  [DOMMatrixReadOnly interface: default toJSON operation on new DOMMatrixReadOnly()]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/geometry/interfaces.worker.js.ini b/tests/wpt/metadata/css/geometry/interfaces.worker.js.ini
index f21695bbfdc..5ca33a54aab 100644
--- a/tests/wpt/metadata/css/geometry/interfaces.worker.js.ini
+++ b/tests/wpt/metadata/css/geometry/interfaces.worker.js.ini
@@ -29,75 +29,8 @@
   [DOMRectReadOnly interface: calling fromRect(DOMRectInit) on new DOMRect() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [DOMPointReadOnly interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMPointReadOnly interface: new DOMPointReadOnly() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMPointReadOnly]
-    expected: FAIL
-
-  [DOMPointReadOnly interface: new DOMPoint() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMPoint]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: new DOMRectReadOnly() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMRectReadOnly]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: new DOMRect() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMRect]
-    expected: FAIL
-
-  [DOMQuad interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMQuad interface: new DOMQuad() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMQuad]
-    expected: FAIL
-
-  [DOMMatrixReadOnly interface: operation toJSON()]
-    expected: FAIL
-
-  [DOMMatrixReadOnly interface: new DOMMatrixReadOnly() must inherit property "toJSON()" with the proper type]
-    expected: FAIL
-
-  [Test default toJSON operation of DOMMatrixReadOnly]
-    expected: FAIL
-
   [Untitled]
     expected: FAIL
 
   [interfaces]
     expected: FAIL
-
-  [DOMPointReadOnly interface: default toJSON operation on new DOMPoint()]
-    expected: FAIL
-
-  [DOMPointReadOnly interface: default toJSON operation on new DOMPointReadOnly()]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: default toJSON operation on new DOMRect()]
-    expected: FAIL
-
-  [DOMRectReadOnly interface: default toJSON operation on new DOMRectReadOnly()]
-    expected: FAIL
-
-  [DOMQuad interface: default toJSON operation on new DOMQuad()]
-    expected: FAIL
-
-  [DOMMatrixReadOnly interface: default toJSON operation on new DOMMatrixReadOnly()]
-    expected: FAIL
-