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5c1723c983
This fixes many rustdoc errors that occur due to raw URLs in rustdoc comments as well as unescaped Rust code that should be in backticks.
65 lines
2.2 KiB
Rust
65 lines
2.2 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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//! Reference-counted pointers to flows.
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//!
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//! Eventually, with dynamically sized types in Rust, much of this code will
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//! be superfluous. This design is largely duplicating logic of `Arc<T>` and
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//! `Weak<T>`; please see comments there for details.
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use std::ops::Deref;
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use std::sync::{Arc, Weak};
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use crate::flow::Flow;
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#[derive(Clone, Debug)]
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pub struct FlowRef(Arc<dyn Flow>);
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impl Deref for FlowRef {
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type Target = dyn Flow;
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fn deref(&self) -> &dyn Flow {
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self.0.deref()
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}
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}
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impl FlowRef {
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/// `FlowRef`s can only be made available to the traversal code.
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/// See <https://github.com/servo/servo/issues/14014> for more details.
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pub fn new(mut r: Arc<dyn Flow>) -> Self {
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// This assertion checks that this `FlowRef` does not alias normal `Arc`s.
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// If that happens, we're in trouble.
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assert!(Arc::get_mut(&mut r).is_some());
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FlowRef(r)
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}
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pub fn get_mut(this: &mut FlowRef) -> Option<&mut dyn Flow> {
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Arc::get_mut(&mut this.0)
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}
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pub fn downgrade(this: &FlowRef) -> WeakFlowRef {
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WeakFlowRef(Arc::downgrade(&this.0))
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}
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pub fn into_arc(mut this: FlowRef) -> Arc<dyn Flow> {
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// This assertion checks that this `FlowRef` does not alias normal `Arc`s.
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// If that happens, we're in trouble.
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assert!(FlowRef::get_mut(&mut this).is_some());
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this.0
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}
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/// WARNING: This should only be used when there is no aliasing:
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/// when the traversal ensures that no other threads accesses the same flow at the same time.
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/// See <https://github.com/servo/servo/issues/6503>.
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/// Use Arc::get_mut instead when possible (e.g. on an Arc that was just created).
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#[allow(unsafe_code)]
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pub fn deref_mut(this: &mut FlowRef) -> &mut dyn Flow {
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let ptr: *const dyn Flow = &*this.0;
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unsafe { &mut *(ptr as *mut dyn Flow) }
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}
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}
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#[derive(Clone, Debug)]
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pub struct WeakFlowRef(Weak<dyn Flow>);
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impl WeakFlowRef {
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pub fn upgrade(&self) -> Option<FlowRef> {
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self.0.upgrade().map(FlowRef)
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}
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}
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