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* extract code into CachedFrozenArray Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com> * fix borrow crash Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com> * fix already borrowed error using an else will cause the borrow to live more than it needs Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com> * restore return statement Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com> --------- Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com>
52 lines
1.4 KiB
Rust
52 lines
1.4 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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use js::conversions::ToJSValConvertible;
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use js::jsapi::Heap;
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use js::jsval::JSVal;
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use js::rust::MutableHandleValue;
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use crate::dom::bindings::cell::DomRefCell;
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use crate::dom::bindings::utils::to_frozen_array;
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use crate::script_runtime::JSContext;
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#[derive(JSTraceable)]
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pub struct CachedFrozenArray {
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frozen_value: DomRefCell<Option<Heap<JSVal>>>,
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}
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impl CachedFrozenArray {
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pub fn new() -> CachedFrozenArray {
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CachedFrozenArray {
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frozen_value: DomRefCell::new(None),
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}
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}
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pub fn get_or_init<F: FnOnce() -> Vec<T>, T: ToJSValConvertible>(
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&self,
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f: F,
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cx: JSContext,
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mut retval: MutableHandleValue,
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) {
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if let Some(inner) = &*self.frozen_value.borrow() {
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retval.set(inner.get());
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return;
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}
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let array = f();
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to_frozen_array(array.as_slice(), cx, retval);
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// Safety: need to create the Heap value in its final memory location before setting it.
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*self.frozen_value.borrow_mut() = Some(Heap::default());
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self.frozen_value
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.borrow()
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.as_ref()
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.unwrap()
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.set(retval.get());
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}
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pub fn clear(&self) {
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*self.frozen_value.borrow_mut() = None;
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}
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}
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