forked from mirrors/gecko-dev
6a64854c0e
This also fixes Undefined Behavior in build_display_list_for_subtree. Source-Repo: https://github.com/servo/servo Source-Revision: a316fb73e5fb1b086516ba6786c5ae4c302c3c62
28 lines
1 KiB
Rust
28 lines
1 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 http://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 flow::Flow;
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use std::sync::{Arc, Weak};
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pub type FlowRef = Arc<Flow>;
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pub type WeakFlowRef = Weak<Flow>;
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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<'a>(r: &'a mut FlowRef) -> &'a mut Flow {
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let ptr: *const Flow = &**r;
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unsafe {
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&mut *(ptr as *mut Flow)
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}
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}
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