This commit adds two new types of scopes:
- DisallowJavascriptExecutionScope
- AllowJavascriptExecutionScope
The first one can be used to prevent execution of JavaScript
(with customizable behavior on an attempt of executing JS, eg.
crashing the process); while the second one can be constructed
from the first to temporarily enable executing JS.
These are useful for "value serializers" to prevent user defined objects
from causing unintended behavior.
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Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
The `get_current_context()` and `get_entered_or_microtask_context()`
methods now return `Option<Local<Context>>` to reflect that an isolate
may not have entered any context.
They're also moved from `Isolate` to `struct Entered` because it turns
out that the underlying V8 API calls actually create new local handles,
hence they should only be used inside an active HandleScope.
The `InContext` trait has been removed.
A test exercising `ContextScope` and the `get_*_context()` methods
mentioned above was added.
Closes: #248.
