Struct v8::CallbackScope

pub struct CallbackScope<'s, C = Context> { /* fields omitted */ }

A CallbackScope can be used to bootstrap a HandleScope and ContextScope inside a callback function that gets called by V8. Bootstrapping a scope inside a callback is the only valid use case of this type; using it in other places leads to undefined behavior, which is also the reason CallbackScope::new() is marked as being an unsafe function.

For some callback types, rusty_v8 internally creates a scope and passes it as an argument to to embedder callback. Eventually we intend to wrap all callbacks in this fashion, so the embedder would never needs to construct a CallbackScope.

A CallbackScope<()>, without context, can be created from:

• &mut Isolate
• &mut OwnedIsolate

A CallbackScope, with context, can be created from:

• Local<Context>
• Local<Message>
• Local<Object>
• Local<Promise>
• Local<SharedArrayBuffer>
• &FunctionCallbackInfo
• &PropertyCallbackInfo
• &PromiseRejectMessage

Implementations

impl<'s> CallbackScope<'s>

pub unsafe fn new<P: NewCallbackScope<'s>>(param: P) -> P::NewScope

Methods from Deref<Target = HandleScope<'s, ()>>

pub fn get_current_context(&self) -> Local<'s, Context>

Returns the context of the currently running JavaScript, or the context on the top of the stack if no JavaScript is running.

pub fn get_entered_or_microtask_context(&self) -> Local<'s, Context>

Returns either the last context entered through V8’s C++ API, or the context of the currently running microtask while processing microtasks. If a context is entered while executing a microtask, that context is returned.

pub fn throw_exception(
    &mut self,
    exception: Local<'_, Value>
) -> Local<'s, Value>

Schedules an exception to be thrown when returning to JavaScript. When an exception has been scheduled it is illegal to invoke any JavaScript operation; the caller must return immediately and only after the exception has been handled does it become legal to invoke JavaScript operations.

This function always returns the undefined value.

pub fn get_isolate_data_from_snapshot_once<T>(
    &mut self,
    index: usize
) -> Result<Local<'s, T>, DataError> where
    T: 'static,
    for<'l> Local<'l, Data>: TryInto<Local<'l, T>, Error = DataError>, 

Return data that was previously attached to the isolate snapshot via SnapshotCreator, and removes the reference to it. If called again with same index argument, this function returns DataError::NoData.

The value that was stored in the snapshot must either match or be convertible to type parameter T, otherwise DataError::BadType is returned.

pub fn get_context_data_from_snapshot_once<T>(
    &mut self,
    index: usize
) -> Result<Local<'s, T>, DataError> where
    T: 'static,
    for<'l> Local<'l, Data>: TryInto<Local<'l, T>, Error = DataError>, 

Return data that was previously attached to the context snapshot via SnapshotCreator, and removes the reference to it. If called again with same index argument, this function returns DataError::NoData.

The value that was stored in the snapshot must either match or be convertible to type parameter T, otherwise DataError::BadType is returned.

Trait Implementations

impl<'s, C> AsMut<HandleScope<'s, ()>> for CallbackScope<'s, C>

fn as_mut(&mut self) -> &mut HandleScope<'s, ()>

Performs the conversion.

impl<'s> AsMut<HandleScope<'s, Context>> for CallbackScope<'s>

fn as_mut(&mut self) -> &mut HandleScope<'s>

Performs the conversion.

impl<'s, C> AsMut<Isolate> for CallbackScope<'s, C>

fn as_mut(&mut self) -> &mut Isolate

Performs the conversion.

impl<'s, C> AsRef<HandleScope<'s, ()>> for CallbackScope<'s, C>

fn as_ref(&self) -> &HandleScope<'s, ()>

Performs the conversion.

impl<'s> AsRef<HandleScope<'s, Context>> for CallbackScope<'s>

fn as_ref(&self) -> &HandleScope<'s>

Performs the conversion.

impl<'s, C> AsRef<Isolate> for CallbackScope<'s, C>

fn as_ref(&self) -> &Isolate

Performs the conversion.

impl<'s, C: Debug> Debug for CallbackScope<'s, C>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'s> Deref for CallbackScope<'s, ()>

type Target = HandleScope<'s, ()>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'s> Deref for CallbackScope<'s>

type Target = HandleScope<'s>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'s> DerefMut for CallbackScope<'s, ()>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'s> DerefMut for CallbackScope<'s>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'s, C> Drop for CallbackScope<'s, C>

fn drop(&mut self)

Executes the destructor for this type.