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1ed35fd22e
This change adds support for weak handles that don't prevent GC of the referenced objects, through the `v8::Weak<T>` API. A weak handle can be empty (if it was created empty or its object was GC'd) or non-empty, and if non-empty it allows getting its object as a global or local. When creating a `v8::Weak` you can also set a finalizer that will be called at some point after the object is GC'd, as long as the weak handle is still alive at that point. This finalization corresponds to the second-pass callback in `kParameter` mode in the C++ API, so it will only be called after the object is GC'd. The finalizer function is a `FnOnce` that may close over data, and which takes a `&mut Isolate` as an argument. The C++ finalization API doesn't guarantee _when_ or even _if_ the finalizer will ever be called, but in order to prevent memory leaks, the rusty_v8 wrapper ensures that it will be called at some point, even if it's just before the isolate gets dropped. `v8::Weak<T>` implements `Clone`, but a finalizer is tied to a single weak handle, so its clones won't be able to keep the finalizer alive. And in fact, cloning will create a new weak handle that isn't tied to a finalizer at all. `v8::Weak::clone_with_finalizer` can be used to make a clone of a weak handle which has a finalizer tied to it. Note that `v8::Weak<T>` doesn't implement `Hash`, because the hash would have to change once the handle's object is GC'd, which is a big gotcha and would break some of the algorithms that rely on hashes, such as the Rust std's `HashMap`. |
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| .. | ||
| compile_fail | ||
| slots.rs | ||
| test_api.rs | ||
| test_api_entropy_source.rs | ||
| test_api_flags.rs | ||
| test_concurrent_isolate_creation_and_disposal.rs | ||
| test_platform_atomics_pump_message_loop.rs | ||
| test_single_threaded_default_platform.rs | ||
| test_ui.rs | ||