servo/components/script/dom/bindings/conversions.rs
2015-10-14 15:30:57 -04:00

780 lines
26 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! Conversions of Rust values to and from `JSVal`.
//!
//! | IDL type | Argument type | Return type |
//! |-------------------------|-----------------|----------------|
//! | any | `JSVal` |
//! | boolean | `bool` |
//! | byte | `i8` |
//! | octet | `u8` |
//! | short | `i16` |
//! | unsigned short | `u16` |
//! | long | `i32` |
//! | unsigned long | `u32` |
//! | long long | `i64` |
//! | unsigned long long | `u64` |
//! | unrestricted float | `f32` |
//! | float | `Finite<f32>` |
//! | unrestricted double | `f64` |
//! | double | `Finite<f64>` |
//! | DOMString | `DOMString` |
//! | USVString | `USVString` |
//! | ByteString | `ByteString` |
//! | object | `*mut JSObject` |
//! | interface types | `&T` | `Root<T>` |
//! | dictionary types | `&T` | *unsupported* |
//! | enumeration types | `T` |
//! | callback function types | `Rc<T>` |
//! | nullable types | `Option<T>` |
//! | sequences | `Vec<T>` |
//! | union types | `T` |
use core::nonzero::NonZero;
use dom::bindings::codegen::PrototypeList;
use dom::bindings::error::throw_type_error;
use dom::bindings::js::Root;
use dom::bindings::num::Finite;
use dom::bindings::str::{ByteString, USVString};
use dom::bindings::utils::{DOMClass, Reflectable, Reflector};
use js;
use js::glue::{GetProxyPrivate, IsWrapper, RUST_JS_NumberValue};
use js::glue::{RUST_JSID_IS_STRING, RUST_JSID_TO_STRING, UnwrapObject};
use js::jsapi::{HandleId, HandleObject, HandleValue, JS_GetClass};
use js::jsapi::{JSClass, JSContext, JSObject, JSString, MutableHandleValue};
use js::jsapi::{JS_GetLatin1StringCharsAndLength, JS_GetReservedSlot};
use js::jsapi::{JS_GetTwoByteStringCharsAndLength, JS_NewStringCopyN};
use js::jsapi::{JS_NewUCStringCopyN, JS_StringHasLatin1Chars, JS_WrapValue};
use js::jsval::{BooleanValue, Int32Value, NullValue, UInt32Value, UndefinedValue};
use js::jsval::{JSVal, ObjectOrNullValue, ObjectValue, StringValue};
use js::rust::{ToBoolean, ToNumber, ToString, ToUint16};
use js::rust::{ToInt32, ToUint32};
use js::rust::{ToInt64, ToUint64};
use libc;
use num::Float;
use num::traits::{Bounded, Zero};
use std::borrow::ToOwned;
use std::rc::Rc;
use std::{char, ptr, slice};
use util::str::DOMString;
trait As<O>: Copy {
fn cast(self) -> O;
}
macro_rules! impl_as {
($I:ty, $O:ty) => (
impl As<$O> for $I {
fn cast(self) -> $O {
self as $O
}
}
)
}
impl_as!(f64, u8);
impl_as!(f64, u16);
impl_as!(f64, u32);
impl_as!(f64, u64);
impl_as!(f64, i8);
impl_as!(f64, i16);
impl_as!(f64, i32);
impl_as!(f64, i64);
impl_as!(u8, f64);
impl_as!(u16, f64);
impl_as!(u32, f64);
impl_as!(u64, f64);
impl_as!(i8, f64);
impl_as!(i16, f64);
impl_as!(i32, f64);
impl_as!(i64, f64);
impl_as!(i32, i8);
impl_as!(i32, u8);
impl_as!(i32, i16);
impl_as!(u16, u16);
impl_as!(i32, i32);
impl_as!(u32, u32);
impl_as!(i64, i64);
impl_as!(u64, u64);
/// A trait to retrieve the constants necessary to check if a `JSObject`
/// implements a given interface.
pub trait IDLInterface {
/// Returns the prototype ID.
fn get_prototype_id() -> PrototypeList::ID;
/// Returns the prototype depth, i.e., the number of interfaces this
/// interface inherits from.
fn get_prototype_depth() -> usize;
}
/// A trait to convert Rust types to `JSVal`s.
pub trait ToJSValConvertible {
/// Convert `self` to a `JSVal`. JSAPI failure causes a task failure.
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue);
}
/// A trait to convert `JSVal`s to Rust types.
pub trait FromJSValConvertible: Sized {
/// Optional configurable behaviour switch; use () for no configuration.
type Config;
/// Convert `val` to type `Self`.
/// Optional configuration of type `T` can be passed as the `option`
/// argument.
/// If it returns `Err(())`, a JSAPI exception is pending.
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: Self::Config) -> Result<Self, ()>;
}
/// Behavior for converting out-of-range integers.
#[derive(PartialEq, Eq)]
pub enum ConversionBehavior {
/// Wrap into the integer's range.
Default,
/// Throw an exception.
EnforceRange,
/// Clamp into the integer's range.
Clamp
}
/// Try to cast the number to a smaller type, but
/// if it doesn't fit, it will return an error.
fn enforce_range<D>(cx: *mut JSContext, d: f64) -> Result<D, ()>
where D: Bounded + As<f64>,
f64: As<D>
{
if d.is_infinite() {
throw_type_error(cx, "value out of range in an EnforceRange argument");
return Err(());
}
let rounded = d.round();
if D::min_value().cast() <= rounded && rounded <= D::max_value().cast() {
Ok(rounded.cast())
} else {
throw_type_error(cx, "value out of range in an EnforceRange argument");
Err(())
}
}
/// Try to cast the number to a smaller type, but if it doesn't fit,
/// round it to the MAX or MIN of the source type before casting it to
/// the destination type.
fn clamp_to<D>(d: f64) -> D
where D: Bounded + As<f64> + Zero,
f64: As<D>
{
if d.is_nan() {
D::zero()
} else if d > D::max_value().cast() {
D::max_value()
} else if d < D::min_value().cast() {
D::min_value()
} else {
d.cast()
}
}
impl ToJSValConvertible for () {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(UndefinedValue());
}
}
impl ToJSValConvertible for JSVal {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(*self);
if unsafe { !JS_WrapValue(cx, rval) } {
panic!("JS_WrapValue failed.");
}
}
}
impl ToJSValConvertible for HandleValue {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(self.get());
if unsafe { !JS_WrapValue(cx, rval) } {
panic!("JS_WrapValue failed.");
}
}
}
#[inline]
fn convert_int_from_jsval<T, M>(cx: *mut JSContext, value: HandleValue,
option: ConversionBehavior,
convert_fn: fn(*mut JSContext, HandleValue) -> Result<M, ()>)
-> Result<T, ()>
where T: Bounded + Zero + As<f64>,
M: Zero + As<T>,
f64: As<T>
{
match option {
ConversionBehavior::Default => Ok(try!(convert_fn(cx, value)).cast()),
ConversionBehavior::EnforceRange => enforce_range(cx, try!(ToNumber(cx, value))),
ConversionBehavior::Clamp => Ok(clamp_to(try!(ToNumber(cx, value)))),
}
}
impl ToJSValConvertible for bool {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(BooleanValue(*self));
}
}
impl FromJSValConvertible for bool {
type Config = ();
fn from_jsval(_cx: *mut JSContext, val: HandleValue, _option: ()) -> Result<bool, ()> {
Ok(ToBoolean(val))
}
}
impl ToJSValConvertible for i8 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(Int32Value(*self as i32));
}
}
impl FromJSValConvertible for i8 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<i8, ()> {
convert_int_from_jsval(cx, val, option, ToInt32)
}
}
impl ToJSValConvertible for u8 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(Int32Value(*self as i32));
}
}
impl FromJSValConvertible for u8 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<u8, ()> {
convert_int_from_jsval(cx, val, option, ToInt32)
}
}
impl ToJSValConvertible for i16 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(Int32Value(*self as i32));
}
}
impl FromJSValConvertible for i16 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<i16, ()> {
convert_int_from_jsval(cx, val, option, ToInt32)
}
}
impl ToJSValConvertible for u16 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(Int32Value(*self as i32));
}
}
impl FromJSValConvertible for u16 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<u16, ()> {
convert_int_from_jsval(cx, val, option, ToUint16)
}
}
impl ToJSValConvertible for i32 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(Int32Value(*self));
}
}
impl FromJSValConvertible for i32 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<i32, ()> {
convert_int_from_jsval(cx, val, option, ToInt32)
}
}
impl ToJSValConvertible for u32 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(UInt32Value(*self));
}
}
impl FromJSValConvertible for u32 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<u32, ()> {
convert_int_from_jsval(cx, val, option, ToUint32)
}
}
impl ToJSValConvertible for i64 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
unsafe {
rval.set(RUST_JS_NumberValue(*self as f64));
}
}
}
impl FromJSValConvertible for i64 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<i64, ()> {
convert_int_from_jsval(cx, val, option, ToInt64)
}
}
impl ToJSValConvertible for u64 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
unsafe {
rval.set(RUST_JS_NumberValue(*self as f64));
}
}
}
impl FromJSValConvertible for u64 {
type Config = ConversionBehavior;
fn from_jsval(cx: *mut JSContext, val: HandleValue, option: ConversionBehavior) -> Result<u64, ()> {
convert_int_from_jsval(cx, val, option, ToUint64)
}
}
impl ToJSValConvertible for f32 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
unsafe {
rval.set(RUST_JS_NumberValue(*self as f64));
}
}
}
impl FromJSValConvertible for f32 {
type Config = ();
fn from_jsval(cx: *mut JSContext, val: HandleValue, _option: ()) -> Result<f32, ()> {
let result = ToNumber(cx, val);
result.map(|f| f as f32)
}
}
impl ToJSValConvertible for f64 {
fn to_jsval(&self, _cx: *mut JSContext, rval: MutableHandleValue) {
unsafe {
rval.set(RUST_JS_NumberValue(*self));
}
}
}
impl FromJSValConvertible for f64 {
type Config = ();
fn from_jsval(cx: *mut JSContext, val: HandleValue, _option: ()) -> Result<f64, ()> {
ToNumber(cx, val)
}
}
impl<T: Float + ToJSValConvertible> ToJSValConvertible for Finite<T> {
#[inline]
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
let value = **self;
value.to_jsval(cx, rval);
}
}
impl<T: Float + FromJSValConvertible<Config=()>> FromJSValConvertible for Finite<T> {
type Config = ();
fn from_jsval(cx: *mut JSContext, value: HandleValue, option: ()) -> Result<Finite<T>, ()> {
let result = try!(FromJSValConvertible::from_jsval(cx, value, option));
match Finite::new(result) {
Some(v) => Ok(v),
None => {
throw_type_error(cx, "this argument is not a finite floating-point value");
Err(())
},
}
}
}
impl ToJSValConvertible for str {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
let mut string_utf16: Vec<u16> = Vec::with_capacity(self.len());
unsafe {
string_utf16.extend(self.utf16_units());
let jsstr = JS_NewUCStringCopyN(cx, string_utf16.as_ptr(),
string_utf16.len() as libc::size_t);
if jsstr.is_null() {
panic!("JS_NewUCStringCopyN failed");
}
rval.set(StringValue(&*jsstr));
}
}
}
impl ToJSValConvertible for DOMString {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
(**self).to_jsval(cx, rval);
}
}
/// Behavior for stringification of `JSVal`s.
#[derive(PartialEq)]
pub enum StringificationBehavior {
/// Convert `null` to the string `"null"`.
Default,
/// Convert `null` to the empty string.
Empty,
}
/// Convert the given `JSString` to a `DOMString`. Fails if the string does not
/// contain valid UTF-16.
pub fn jsstring_to_str(cx: *mut JSContext, s: *mut JSString) -> DOMString {
let mut length = 0;
let latin1 = unsafe { JS_StringHasLatin1Chars(s) };
if latin1 {
let chars = unsafe {
JS_GetLatin1StringCharsAndLength(cx, ptr::null(), s, &mut length)
};
assert!(!chars.is_null());
let mut buf = String::with_capacity(length as usize);
for i in 0..(length as isize) {
unsafe {
buf.push(*chars.offset(i) as char);
}
}
buf
} else {
let chars = unsafe {
JS_GetTwoByteStringCharsAndLength(cx, ptr::null(), s, &mut length)
};
assert!(!chars.is_null());
let potentially_ill_formed_utf16 = unsafe {
slice::from_raw_parts(chars as *const u16, length as usize)
};
let mut s = String::with_capacity(length as usize);
for item in char::decode_utf16(potentially_ill_formed_utf16.iter().cloned()) {
match item {
Ok(c) => s.push(c),
Err(_) => {
// FIXME: Add more info like document URL in the message?
macro_rules! message {
() => {
"Found an unpaired surrogate in a DOM string. \
If you see this in real web content, \
please comment on https://github.com/servo/servo/issues/6564"
}
}
if ::util::opts::get().replace_surrogates {
error!(message!());
s.push('\u{FFFD}');
} else {
panic!(concat!(message!(), " Use `-Z replace-surrogates` \
on the command line to make this non-fatal."));
}
}
}
}
s
}
}
/// Convert the given `jsid` to a `DOMString`. Fails if the `jsid` is not a
/// string, or if the string does not contain valid UTF-16.
pub fn jsid_to_str(cx: *mut JSContext, id: HandleId) -> DOMString {
unsafe {
assert!(RUST_JSID_IS_STRING(id));
jsstring_to_str(cx, RUST_JSID_TO_STRING(id))
}
}
impl FromJSValConvertible for DOMString {
type Config = StringificationBehavior;
fn from_jsval(cx: *mut JSContext, value: HandleValue,
null_behavior: StringificationBehavior)
-> Result<DOMString, ()> {
if null_behavior == StringificationBehavior::Empty &&
value.get().is_null() {
Ok("".to_owned())
} else {
let jsstr = ToString(cx, value);
if jsstr.is_null() {
debug!("ToString failed");
Err(())
} else {
Ok(jsstring_to_str(cx, jsstr))
}
}
}
}
impl ToJSValConvertible for USVString {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
self.0.to_jsval(cx, rval);
}
}
impl FromJSValConvertible for USVString {
type Config = ();
fn from_jsval(cx: *mut JSContext, value: HandleValue, _: ())
-> Result<USVString, ()> {
let jsstr = ToString(cx, value);
if jsstr.is_null() {
debug!("ToString failed");
return Err(());
}
let latin1 = unsafe { JS_StringHasLatin1Chars(jsstr) };
if latin1 {
return Ok(USVString(jsstring_to_str(cx, jsstr)));
}
unsafe {
let mut length = 0;
let chars = JS_GetTwoByteStringCharsAndLength(cx, ptr::null(), jsstr, &mut length);
assert!(!chars.is_null());
let char_vec = slice::from_raw_parts(chars as *const u16, length as usize);
Ok(USVString(String::from_utf16_lossy(char_vec)))
}
}
}
impl ToJSValConvertible for ByteString {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
unsafe {
let jsstr = JS_NewStringCopyN(cx, self.as_ptr() as *const libc::c_char,
self.len() as libc::size_t);
if jsstr.is_null() {
panic!("JS_NewStringCopyN failed");
}
rval.set(StringValue(&*jsstr));
}
}
}
impl FromJSValConvertible for ByteString {
type Config = ();
fn from_jsval(cx: *mut JSContext, value: HandleValue, _option: ()) -> Result<ByteString, ()> {
let string = ToString(cx, value);
if string.is_null() {
debug!("ToString failed");
return Err(());
}
let latin1 = unsafe { JS_StringHasLatin1Chars(string) };
if latin1 {
let mut length = 0;
let chars = unsafe {
JS_GetLatin1StringCharsAndLength(cx, ptr::null(),
string, &mut length)
};
assert!(!chars.is_null());
let char_slice = unsafe {
slice::from_raw_parts(chars as *mut u8, length as usize)
};
return Ok(ByteString::new(char_slice.to_vec()));
}
unsafe {
let mut length = 0;
let chars = JS_GetTwoByteStringCharsAndLength(cx, ptr::null(), string, &mut length);
let char_vec = slice::from_raw_parts(chars, length as usize);
if char_vec.iter().any(|&c| c > 0xFF) {
throw_type_error(cx, "Invalid ByteString");
Err(())
} else {
Ok(ByteString::new(char_vec.iter().map(|&c| c as u8).collect()))
}
}
}
}
impl ToJSValConvertible for Reflector {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
let obj = self.get_jsobject().get();
assert!(!obj.is_null());
rval.set(ObjectValue(unsafe { &*obj }));
if unsafe { !JS_WrapValue(cx, rval) } {
panic!("JS_WrapValue failed.");
}
}
}
/// Returns whether the given `clasp` is one for a DOM object.
pub fn is_dom_class(clasp: *const JSClass) -> bool {
unsafe {
((*clasp).flags & js::JSCLASS_IS_DOMJSCLASS) != 0
}
}
/// Returns whether `obj` is a DOM object implemented as a proxy.
pub fn is_dom_proxy(obj: *mut JSObject) -> bool {
use js::glue::IsProxyHandlerFamily;
unsafe {
let clasp = JS_GetClass(obj);
((*clasp).flags & js::JSCLASS_IS_PROXY) != 0 && IsProxyHandlerFamily(obj) != 0
}
}
/// The index of the slot wherein a pointer to the reflected DOM object is
/// stored for non-proxy bindings.
// We use slot 0 for holding the raw object. This is safe for both
// globals and non-globals.
pub const DOM_OBJECT_SLOT: u32 = 0;
/// Get the private pointer of a DOM object from a given reflector.
unsafe fn private_from_reflector(obj: *mut JSObject) -> *const libc::c_void {
let clasp = JS_GetClass(obj);
let value = if is_dom_class(clasp) {
JS_GetReservedSlot(obj, DOM_OBJECT_SLOT)
} else {
debug_assert!(is_dom_proxy(obj));
GetProxyPrivate(obj)
};
if value.is_undefined() {
ptr::null()
} else {
value.to_private()
}
}
/// Get the DOM object from the given reflector.
pub unsafe fn native_from_reflector<T>(obj: *mut JSObject) -> *const T {
private_from_reflector(obj) as *const T
}
/// Get the `DOMClass` from `obj`, or `Err(())` if `obj` is not a DOM object.
pub unsafe fn get_dom_class(obj: *mut JSObject) -> Result<&'static DOMClass, ()> {
use dom::bindings::utils::DOMJSClass;
use js::glue::GetProxyHandlerExtra;
let clasp = JS_GetClass(obj);
if is_dom_class(&*clasp) {
debug!("plain old dom object");
let domjsclass: *const DOMJSClass = clasp as *const DOMJSClass;
return Ok(&(&*domjsclass).dom_class);
}
if is_dom_proxy(obj) {
debug!("proxy dom object");
let dom_class: *const DOMClass = GetProxyHandlerExtra(obj) as *const DOMClass;
return Ok(&*dom_class);
}
debug!("not a dom object");
Err(())
}
/// Get a `*const libc::c_void` for the given DOM object, unwrapping any
/// wrapper around it first, and checking if the object is of the correct type.
///
/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
/// not an object for a DOM object of the given type (as defined by the
/// proto_id and proto_depth).
pub unsafe fn private_from_proto_chain(mut obj: *mut JSObject,
proto_id: u16, proto_depth: u16)
-> Result<*const libc::c_void, ()> {
let dom_class = try!(get_dom_class(obj).or_else(|_| {
if IsWrapper(obj) {
debug!("found wrapper");
obj = UnwrapObject(obj, /* stopAtOuter = */ 0);
if obj.is_null() {
debug!("unwrapping security wrapper failed");
Err(())
} else {
assert!(!IsWrapper(obj));
debug!("unwrapped successfully");
get_dom_class(obj)
}
} else {
debug!("not a dom wrapper");
Err(())
}
}));
if dom_class.interface_chain[proto_depth as usize] as u16 == proto_id {
debug!("good prototype");
Ok(private_from_reflector(obj))
} else {
debug!("bad prototype");
Err(())
}
}
/// Get a `Root<T>` for the given DOM object, unwrapping any wrapper
/// around it first, and checking if the object is of the correct type.
///
/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
/// not a reflector for a DOM object of the given type (as defined by the
/// proto_id and proto_depth).
pub fn native_from_reflector_jsmanaged<T>(obj: *mut JSObject) -> Result<Root<T>, ()>
where T: Reflectable + IDLInterface
{
let proto_id = <T as IDLInterface>::get_prototype_id() as u16;
let proto_depth = <T as IDLInterface>::get_prototype_depth() as u16;
unsafe {
private_from_proto_chain(obj, proto_id, proto_depth).map(|obj| {
Root::new(NonZero::new(obj as *const T))
})
}
}
/// Get a Rooted<T> for a DOM object accessible from a HandleValue
pub fn native_from_handlevalue<T>(v: HandleValue) -> Result<Root<T>, ()>
where T: Reflectable + IDLInterface
{
native_from_reflector_jsmanaged(v.get().to_object())
}
/// Get a Rooted<T> for a DOM object accessible from a HandleObject
pub fn native_from_handleobject<T>(obj: HandleObject) -> Result<Root<T>, ()>
where T: Reflectable + IDLInterface
{
native_from_reflector_jsmanaged(obj.get())
}
impl<T: Reflectable> ToJSValConvertible for Root<T> {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
self.r().reflector().to_jsval(cx, rval);
}
}
impl<'a, T: Reflectable> ToJSValConvertible for &'a T {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
self.reflector().to_jsval(cx, rval);
}
}
impl<T: ToJSValConvertible> ToJSValConvertible for Option<T> {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
match self {
&Some(ref value) => value.to_jsval(cx, rval),
&None => rval.set(NullValue()),
}
}
}
impl<T: ToJSValConvertible> ToJSValConvertible for Option<Rc<T>> {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
match self {
&Some(ref value) => (**value).to_jsval(cx, rval),
&None => rval.set(NullValue()),
}
}
}
impl<T: FromJSValConvertible> FromJSValConvertible for Option<T> {
type Config = T::Config;
fn from_jsval(cx: *mut JSContext, value: HandleValue, option: T::Config) -> Result<Option<T>, ()> {
if value.get().is_null_or_undefined() {
Ok(None)
} else {
let result: Result<T, ()> = FromJSValConvertible::from_jsval(cx, value, option);
result.map(Some)
}
}
}
impl ToJSValConvertible for *mut JSObject {
fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
rval.set(ObjectOrNullValue(*self));
unsafe {
assert!(JS_WrapValue(cx, rval));
}
}
}