ae3ff6be00
> Here it is. > > ~~There's two major things that are unfinished here:~~ > - ~~Dealing with the unroot_must_root lint. I'm not sure about the value of this lint with the new rooting API.~~ Done. > - ~~Updating the Cargo.locks to point to the new SM and SM binding.~~ Done. > > I also included my fixes for the rust update, but these will disappear in a rebase. A rust update is necessary to support calling `Drop` on `Heap<T>` correctly when `Heap<T>` is inside a `Rc<T>`. Otherwise `&self` points to the wrong location. > > Incremental GC is disabled here. I'm not sure how to deal with the incremental barriers so that's left for later. > > Generational GC works. SM doesn't work without it. > > The biggest change here is to the rooting API. `Root` was made movable, and `Temporary` and `JSRef` was removed. Movable `Root`s means there's no need for `Temporary`, and `JSRef`s aren't needed generally since it can be assumed that being able to obtain a reference to a dom object means it's already rooted. References have their lifetime bound to the Roots that provided them. DOM objects that haven't passed through `reflect_dom_object` don't need to be rooted, and DOM objects that have passed through `reflect_dom_object` can't be obtained without being rooted through `native_from_reflector_jsmanaged` or `JS::<T>::root()`. > > Support for `Heap<T>` ended up messier than I expected. It's split into two commits, but only because it's a bit difficult to fold them together. Supporting `Heap<T>` properly requires that that `Heap::<T>::set()` be called on something that won't move. I removed the Copy and Clone trait from `Heap<T>` so `Cell` can't hold `Heap<T>` - only `UnsafeCell` can hold it. > > `CallbackObject` is a bit tricky - I moved all callbacks into `Rc<T>` in order to make sure that the pointer inside to a `*mut JSObject` doesn't move. This is necessary for supporting `Heap<T>`. > > `RootedCollectionSet` is very general purpose now. Anything with `JSTraceable` can be rooted by `RootedCollectionSet`/`RootedTraceable`. Right now, `RootedTraceable` is only used to hold down dom objects before they're fully attached to their reflector. I had to make a custom mechanism to dispatch the trace call - couldn't figure out how to get trait objects working for this case. > > This has been tested with the following zeal settings: > > GC after every allocation > JS_GC_ZEAL=2,1 > > GC after every 100 allocations (important for catching use-after-free bugs) > JS_GC_ZEAL=2,100 > > Verify pre barriers > JS_GC_ZEAL=4,1 > > Verify post barriers > JS_GC_ZEAL=11,1 Source-Repo: https://github.com/servo/servo Source-Revision: e7808c526c348fea5e3b48af70b7f1a066652097
62 lines
2.0 KiB
Rust
62 lines
2.0 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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//! This module implements structured cloning, as defined by [HTML]
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//! (https://html.spec.whatwg.org/multipage/#safe-passing-of-structured-data).
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use dom::bindings::error::Fallible;
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use dom::bindings::error::Error::DataClone;
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use dom::bindings::global::GlobalRef;
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use js::glue::JS_STRUCTURED_CLONE_VERSION;
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use js::jsapi::JSContext;
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use js::jsapi::{JS_WriteStructuredClone, JS_ClearPendingException};
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use js::jsapi::JS_ReadStructuredClone;
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use js::jsapi::{HandleValue, MutableHandleValue};
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use libc::size_t;
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use std::ptr;
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/// A buffer for a structured clone.
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pub struct StructuredCloneData {
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data: *mut u64,
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nbytes: size_t,
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}
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impl StructuredCloneData {
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/// Writes a structured clone. Returns a `DataClone` error if that fails.
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pub fn write(cx: *mut JSContext, message: HandleValue)
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-> Fallible<StructuredCloneData> {
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let mut data = ptr::null_mut();
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let mut nbytes = 0;
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let result = unsafe {
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JS_WriteStructuredClone(cx, message, &mut data, &mut nbytes,
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ptr::null(), ptr::null_mut(),
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HandleValue::undefined())
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};
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if result == 0 {
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unsafe { JS_ClearPendingException(cx); }
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return Err(DataClone);
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}
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Ok(StructuredCloneData {
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data: data,
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nbytes: nbytes,
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})
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}
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/// Reads a structured clone.
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///
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/// Panics if `JS_ReadStructuredClone` fails.
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pub fn read(self, global: GlobalRef, rval: MutableHandleValue) {
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unsafe {
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assert!(JS_ReadStructuredClone(
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global.get_cx(), self.data, self.nbytes,
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JS_STRUCTURED_CLONE_VERSION, rval,
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ptr::null(), ptr::null_mut()) != 0);
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}
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}
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}
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unsafe impl Send for StructuredCloneData {}
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