/* 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 https://mozilla.org/MPL/2.0/. */
#![allow(unsafe_code)]
//! Implementation of `iterable<...>` and `iterable<..., ...>` WebIDL declarations.
use std::cell::Cell;
use std::ptr;
use std::ptr::NonNull;
use dom_struct::dom_struct;
use js::conversions::ToJSValConvertible;
use js::jsapi::{Heap, JSObject};
use js::jsval::UndefinedValue;
use js::rust::{HandleObject, HandleValue, MutableHandleObject};
use crate::dom::bindings::codegen::Bindings::IterableIteratorBinding::{
IterableKeyAndValueResult, IterableKeyOrValueResult,
};
use crate::dom::bindings::error::Fallible;
use crate::dom::bindings::reflector::{
reflect_dom_object, DomGlobal, DomObjectIteratorWrap, DomObjectWrap, Reflector,
};
use crate::dom::bindings::root::{Dom, DomRoot, Root};
use crate::dom::bindings::trace::{JSTraceable, RootedTraceableBox};
use crate::dom::globalscope::GlobalScope;
use crate::script_runtime::{CanGc, JSContext};
/// The values that an iterator will iterate over.
#[derive(JSTraceable, MallocSizeOf)]
pub(crate) enum IteratorType {
/// The keys of the iterable object.
Keys,
/// The values of the iterable object.
Values,
/// The keys and values of the iterable object combined.
Entries,
}
/// A DOM object that can be iterated over using a pair value iterator.
pub(crate) trait Iterable {
/// The type of the key of the iterator pair.
type Key: ToJSValConvertible;
/// The type of the value of the iterator pair.
type Value: ToJSValConvertible;
/// Return the number of entries that can be iterated over.
fn get_iterable_length(&self) -> u32;
/// Return the value at the provided index.
fn get_value_at_index(&self, index: u32) -> Self::Value;
/// Return the key at the provided index.
fn get_key_at_index(&self, index: u32) -> Self::Key;
}
/// An iterator over the iterable entries of a given DOM interface.
//FIXME: #12811 prevents dom_struct with type parameters
#[dom_struct]
pub(crate) struct IterableIterator<T: DomObjectIteratorWrap + JSTraceable + Iterable> {
reflector: Reflector,
iterable: Dom<T>,
type_: IteratorType,
index: Cell<u32>,
}
impl<T: DomObjectIteratorWrap + JSTraceable + Iterable> IterableIterator<T> {
/// Create a new iterator instance for the provided iterable DOM interface.
pub(crate) fn new(iterable: &T, type_: IteratorType) -> DomRoot<Self> {
let iterator = Box::new(IterableIterator {
reflector: Reflector::new(),
type_,
iterable: Dom::from_ref(iterable),
index: Cell::new(0),
});
reflect_dom_object(iterator, &*iterable.global(), CanGc::note())
}
/// Return the next value from the iterable object.
#[allow(non_snake_case)]
pub(crate) fn Next(&self, cx: JSContext) -> Fallible<NonNull<JSObject>> {
let index = self.index.get();
rooted!(in(*cx) let mut value = UndefinedValue());
rooted!(in(*cx) let mut rval = ptr::null_mut::<JSObject>());
let result = if index >= self.iterable.get_iterable_length() {
dict_return(cx, rval.handle_mut(), true, value.handle())
} else {
match self.type_ {
IteratorType::Keys => {
unsafe {
self.iterable
.get_key_at_index(index)
.to_jsval(*cx, value.handle_mut());
}
dict_return(cx, rval.handle_mut(), false, value.handle())
},
IteratorType::Values => {
unsafe {
self.iterable
.get_value_at_index(index)
.to_jsval(*cx, value.handle_mut());
}
dict_return(cx, rval.handle_mut(), false, value.handle())
},
IteratorType::Entries => {
rooted!(in(*cx) let mut key = UndefinedValue());
unsafe {
self.iterable
.get_key_at_index(index)
.to_jsval(*cx, key.handle_mut());
self.iterable
.get_value_at_index(index)
.to_jsval(*cx, value.handle_mut());
}
key_and_value_return(cx, rval.handle_mut(), key.handle(), value.handle())
},
}
};
self.index.set(index + 1);
result.map(|_| NonNull::new(rval.get()).expect("got a null pointer"))
}
}
impl<T: DomObjectIteratorWrap + JSTraceable + Iterable> DomObjectWrap for IterableIterator<T> {
const WRAP: unsafe fn(
JSContext,
&GlobalScope,
Option<HandleObject>,
Box<Self>,
CanGc,
) -> Root<Dom<Self>> = T::ITER_WRAP;
}
fn dict_return(
cx: JSContext,
mut result: MutableHandleObject,
done: bool,
value: HandleValue,
) -> Fallible<()> {
let mut dict = IterableKeyOrValueResult::empty();
dict.done = done;
dict.value.set(value.get());
rooted!(in(*cx) let mut dict_value = UndefinedValue());
unsafe {
dict.to_jsval(*cx, dict_value.handle_mut());
}
result.set(dict_value.to_object());
Ok(())
}
fn key_and_value_return(
cx: JSContext,
mut result: MutableHandleObject,
key: HandleValue,
value: HandleValue,
) -> Fallible<()> {
let mut dict = IterableKeyAndValueResult::empty();
dict.done = false;
dict.value = Some(
vec![key, value]
.into_iter()
.map(|handle| RootedTraceableBox::from_box(Heap::boxed(handle.get())))
.collect(),
);
rooted!(in(*cx) let mut dict_value = UndefinedValue());
unsafe {
dict.to_jsval(*cx, dict_value.handle_mut());
}
result.set(dict_value.to_object());
Ok(())
}