pub struct TryCatch<'s, P> { /* private fields */ }Expand description
An external exception handler.
Implementations§
source§impl<'s, P> TryCatch<'s, P>
impl<'s, P> TryCatch<'s, P>
sourcepub fn has_caught(&self) -> bool
pub fn has_caught(&self) -> bool
Returns true if an exception has been caught by this try/catch block.
sourcepub fn can_continue(&self) -> bool
pub fn can_continue(&self) -> bool
For certain types of exceptions, it makes no sense to continue execution.
If CanContinue returns false, the correct action is to perform any C++ cleanup needed and then return. If CanContinue returns false and HasTerminated returns true, it is possible to call CancelTerminateExecution in order to continue calling into the engine.
sourcepub fn has_terminated(&self) -> bool
pub fn has_terminated(&self) -> bool
Returns true if an exception has been caught due to script execution being terminated.
There is no JavaScript representation of an execution termination exception. Such exceptions are thrown when the TerminateExecution methods are called to terminate a long-running script.
If such an exception has been thrown, HasTerminated will return true, indicating that it is possible to call CancelTerminateExecution in order to continue calling into the engine.
sourcepub fn is_verbose(&self) -> bool
pub fn is_verbose(&self) -> bool
Returns true if verbosity is enabled.
sourcepub fn set_verbose(&mut self, value: bool)
pub fn set_verbose(&mut self, value: bool)
Set verbosity of the external exception handler.
By default, exceptions that are caught by an external exception handler are not reported. Call SetVerbose with true on an external exception handler to have exceptions caught by the handler reported as if they were not caught.
sourcepub fn set_capture_message(&mut self, value: bool)
pub fn set_capture_message(&mut self, value: bool)
Set whether or not this TryCatch should capture a Message object which holds source information about where the exception occurred. True by default.
sourcepub fn reset(&mut self)
pub fn reset(&mut self)
Clears any exceptions that may have been caught by this try/catch block. After this method has been called, HasCaught() will return false. Cancels the scheduled exception if it is caught and ReThrow() is not called before.
It is not necessary to clear a try/catch block before using it again; if another exception is thrown the previously caught exception will just be overwritten. However, it is often a good idea since it makes it easier to determine which operation threw a given exception.
source§impl<'s, 'p: 's, P> TryCatch<'s, P>where
Self: AsMut<HandleScope<'p, ()>>,
impl<'s, 'p: 's, P> TryCatch<'s, P>where
Self: AsMut<HandleScope<'p, ()>>,
sourcepub fn exception(&mut self) -> Option<Local<'p, Value>>
pub fn exception(&mut self) -> Option<Local<'p, Value>>
Returns the exception caught by this try/catch block. If no exception has been caught an empty handle is returned.
Note: v8.h states that “the returned handle is valid until this TryCatch block has been destroyed”. This is incorrect; the return value lives no longer and no shorter than the active HandleScope at the time this method is called. An issue has been opened about this in the V8 bug tracker: https://bugs.chromium.org/p/v8/issues/detail?id=10537.
sourcepub fn message(&mut self) -> Option<Local<'p, Message>>
pub fn message(&mut self) -> Option<Local<'p, Message>>
Returns the message associated with this exception. If there is no message associated an empty handle is returned.
Note: the remark about the lifetime for the exception() return value
applies here too.
sourcepub fn rethrow(&mut self) -> Option<Local<'_, Value>>
pub fn rethrow(&mut self) -> Option<Local<'_, Value>>
Throws the exception caught by this TryCatch in a way that avoids it being caught again by this same TryCatch. As with ThrowException it is illegal to execute any JavaScript operations after calling ReThrow; the caller must return immediately to where the exception is caught.
This function returns the undefined value when successful, or None if
no exception was caught and therefore there was nothing to rethrow.
source§impl<'s, 'p: 's, P> TryCatch<'s, P>where
Self: AsMut<HandleScope<'p>>,
impl<'s, 'p: 's, P> TryCatch<'s, P>where
Self: AsMut<HandleScope<'p>>,
sourcepub fn stack_trace(&mut self) -> Option<Local<'p, Value>>
pub fn stack_trace(&mut self) -> Option<Local<'p, Value>>
Returns the .stack property of the thrown object. If no .stack property is present an empty handle is returned.
Methods from Deref<Target = HandleScope<'p, ()>>§
sourcepub fn get_current_context(&self) -> Local<'s, Context>
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.
sourcepub fn get_entered_or_microtask_context(&self) -> Local<'s, Context>
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.
sourcepub fn throw_exception(
&mut self,
exception: Local<'_, Value>
) -> Local<'s, Value>
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.
sourcepub 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>,
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.
sourcepub 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>,
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.
Methods from Deref<Target = Isolate>§
pub fn thread_safe_handle(&self) -> IsolateHandle
sourcepub fn terminate_execution(&self) -> bool
pub fn terminate_execution(&self) -> bool
sourcepub fn cancel_terminate_execution(&self) -> bool
pub fn cancel_terminate_execution(&self) -> bool
sourcepub fn is_execution_terminating(&self) -> bool
pub fn is_execution_terminating(&self) -> bool
sourcepub fn get_data(&self, slot: u32) -> *mut c_void
pub fn get_data(&self, slot: u32) -> *mut c_void
Retrieve embedder-specific data from the isolate.
Returns NULL if SetData has never been called for the given slot.
sourcepub fn set_data(&mut self, slot: u32, data: *mut c_void)
pub fn set_data(&mut self, slot: u32, data: *mut c_void)
Associate embedder-specific data with the isolate. slot has to be
between 0 and Isolate::get_number_of_data_slots().
sourcepub fn get_number_of_data_slots(&self) -> u32
pub fn get_number_of_data_slots(&self) -> u32
Returns the maximum number of available embedder data slots. Valid slots
are in the range of 0 <= n < Isolate::get_number_of_data_slots().
sourcepub fn get_slot<T: 'static>(&self) -> Option<&T>
pub fn get_slot<T: 'static>(&self) -> Option<&T>
Get a reference to embedder data added with set_slot().
sourcepub fn get_slot_mut<T: 'static>(&mut self) -> Option<&mut T>
pub fn get_slot_mut<T: 'static>(&mut self) -> Option<&mut T>
Get a mutable reference to embedder data added with set_slot().
sourcepub fn set_slot<T: 'static>(&mut self, value: T) -> bool
pub fn set_slot<T: 'static>(&mut self, value: T) -> bool
Use with Isolate::get_slot and Isolate::get_slot_mut to associate state with an Isolate.
This method gives ownership of value to the Isolate. Exactly one object of each type can be associated with an Isolate. If called more than once with an object of the same type, the earlier version will be dropped and replaced.
Returns true if value was set without replacing an existing value.
The value will be dropped when the isolate is dropped.
sourcepub fn remove_slot<T: 'static>(&mut self) -> Option<T>
pub fn remove_slot<T: 'static>(&mut self) -> Option<T>
Removes the embedder data added with set_slot() and returns it if it exists.
sourcepub unsafe fn enter(&mut self)
pub unsafe fn enter(&mut self)
Sets this isolate as the entered one for the current thread. Saves the previously entered one (if any), so that it can be restored when exiting. Re-entering an isolate is allowed.
rusty_v8 note: Unlike in the C++ API, the isolate is entered when it is constructed and exited when dropped.
sourcepub unsafe fn exit(&mut self)
pub unsafe fn exit(&mut self)
Exits this isolate by restoring the previously entered one in the current thread. The isolate may still stay the same, if it was entered more than once.
Requires: self == Isolate::GetCurrent().
rusty_v8 note: Unlike in the C++ API, the isolate is entered when it is constructed and exited when dropped.
sourcepub fn clear_kept_objects(&mut self)
pub fn clear_kept_objects(&mut self)
Clears the set of objects held strongly by the heap. This set of objects are originally built when a WeakRef is created or successfully dereferenced.
This is invoked automatically after microtasks are run. See MicrotasksPolicy for when microtasks are run.
This needs to be manually invoked only if the embedder is manually running microtasks via a custom MicrotaskQueue class’s PerformCheckpoint. In that case, it is the embedder’s responsibility to make this call at a time which does not interrupt synchronous ECMAScript code execution.
sourcepub fn low_memory_notification(&mut self)
pub fn low_memory_notification(&mut self)
Optional notification that the system is running low on memory. V8 uses these notifications to attempt to free memory.
sourcepub fn get_heap_statistics(&mut self, s: &mut HeapStatistics)
pub fn get_heap_statistics(&mut self, s: &mut HeapStatistics)
Get statistics about the heap memory usage.
sourcepub fn set_capture_stack_trace_for_uncaught_exceptions(
&mut self,
capture: bool,
frame_limit: i32
)
pub fn set_capture_stack_trace_for_uncaught_exceptions(
&mut self,
capture: bool,
frame_limit: i32
)
Tells V8 to capture current stack trace when uncaught exception occurs and report it to the message listeners. The option is off by default.
sourcepub fn add_message_listener(&mut self, callback: MessageCallback) -> bool
pub fn add_message_listener(&mut self, callback: MessageCallback) -> bool
Adds a message listener (errors only).
The same message listener can be added more than once and in that case it will be called more than once for each message.
The exception object will be passed to the callback.
sourcepub fn set_prepare_stack_trace_callback<'s>(
&mut self,
callback: impl MapFnTo<extern "C" fn(_: Local<'s, Context>, _: Local<'s, Value>, _: Local<'s, Array>) -> PrepareStackTraceCallbackRet>
)
pub fn set_prepare_stack_trace_callback<'s>(
&mut self,
callback: impl MapFnTo<extern "C" fn(_: Local<'s, Context>, _: Local<'s, Value>, _: Local<'s, Array>) -> PrepareStackTraceCallbackRet>
)
This specifies the callback called when the stack property of Error is accessed.
PrepareStackTraceCallback is called when the stack property of an error is first accessed. The return value will be used as the stack value. If this callback is registed, the |Error.prepareStackTrace| API will be disabled. |sites| is an array of call sites, specified in https://v8.dev/docs/stack-trace-api
sourcepub fn set_promise_hook(&mut self, hook: PromiseHook)
pub fn set_promise_hook(&mut self, hook: PromiseHook)
Set the PromiseHook callback for various promise lifecycle events.
sourcepub fn set_promise_reject_callback(&mut self, callback: PromiseRejectCallback)
pub fn set_promise_reject_callback(&mut self, callback: PromiseRejectCallback)
Set callback to notify about promise reject with no handler, or revocation of such a previous notification once the handler is added.
pub fn set_wasm_async_resolve_promise_callback(
&mut self,
callback: extern "C" fn(_: *mut Isolate, _: Local<'_, Context>, _: Local<'_, PromiseResolver>, _: Local<'_, Value>, _: WasmAsyncSuccess)
)
sourcepub fn set_host_initialize_import_meta_object_callback(
&mut self,
callback: HostInitializeImportMetaObjectCallback
)
pub fn set_host_initialize_import_meta_object_callback(
&mut self,
callback: HostInitializeImportMetaObjectCallback
)
This specifies the callback called by the upcoming importa.meta language feature to retrieve host-defined meta data for a module.
sourcepub fn set_host_import_module_dynamically_callback(
&mut self,
callback: impl HostImportModuleDynamicallyCallback
)
pub fn set_host_import_module_dynamically_callback(
&mut self,
callback: impl HostImportModuleDynamicallyCallback
)
This specifies the callback called by the upcoming dynamic import() language feature to load modules.
sourcepub fn set_host_create_shadow_realm_context_callback(
&mut self,
callback: HostCreateShadowRealmContextCallback
)
pub fn set_host_create_shadow_realm_context_callback(
&mut self,
callback: HostCreateShadowRealmContextCallback
)
This specifies the callback called by the upcoming ShadowRealm
construction language feature to retrieve host created globals.
sourcepub fn add_near_heap_limit_callback(
&mut self,
callback: NearHeapLimitCallback,
data: *mut c_void
)
pub fn add_near_heap_limit_callback(
&mut self,
callback: NearHeapLimitCallback,
data: *mut c_void
)
Add a callback to invoke in case the heap size is close to the heap limit. If multiple callbacks are added, only the most recently added callback is invoked.
sourcepub fn remove_near_heap_limit_callback(
&mut self,
callback: NearHeapLimitCallback,
heap_limit: usize
)
pub fn remove_near_heap_limit_callback(
&mut self,
callback: NearHeapLimitCallback,
heap_limit: usize
)
Remove the given callback and restore the heap limit to the given limit. If the given limit is zero, then it is ignored. If the current heap size is greater than the given limit, then the heap limit is restored to the minimal limit that is possible for the current heap size.
sourcepub fn adjust_amount_of_external_allocated_memory(
&mut self,
change_in_bytes: i64
) -> i64
pub fn adjust_amount_of_external_allocated_memory(
&mut self,
change_in_bytes: i64
) -> i64
Adjusts the amount of registered external memory. Used to give V8 an indication of the amount of externally allocated memory that is kept alive by JavaScript objects. V8 uses this to decide when to perform global garbage collections. Registering externally allocated memory will trigger global garbage collections more often than it would otherwise in an attempt to garbage collect the JavaScript objects that keep the externally allocated memory alive.
pub fn set_oom_error_handler(&mut self, callback: OomErrorCallback)
sourcepub fn get_microtasks_policy(&self) -> MicrotasksPolicy
pub fn get_microtasks_policy(&self) -> MicrotasksPolicy
Returns the policy controlling how Microtasks are invoked.
sourcepub fn set_microtasks_policy(&mut self, policy: MicrotasksPolicy)
pub fn set_microtasks_policy(&mut self, policy: MicrotasksPolicy)
Returns the policy controlling how Microtasks are invoked.
sourcepub fn perform_microtask_checkpoint(&mut self)
pub fn perform_microtask_checkpoint(&mut self)
Runs the default MicrotaskQueue until it gets empty and perform other microtask checkpoint steps, such as calling ClearKeptObjects. Asserts that the MicrotasksPolicy is not kScoped. Any exceptions thrown by microtask callbacks are swallowed.
sourcepub fn run_microtasks(&mut self)
👎Deprecated: Use Isolate::perform_microtask_checkpoint() instead
pub fn run_microtasks(&mut self)
An alias for PerformMicrotaskCheckpoint.
sourcepub fn enqueue_microtask(&mut self, microtask: Local<'_, Function>)
pub fn enqueue_microtask(&mut self, microtask: Local<'_, Function>)
Enqueues the callback to the default MicrotaskQueue
sourcepub fn set_allow_atomics_wait(&mut self, allow: bool)
pub fn set_allow_atomics_wait(&mut self, allow: bool)
Set whether calling Atomics.wait (a function that may block) is allowed in this isolate. This can also be configured via CreateParams::allow_atomics_wait.
sourcepub fn set_wasm_streaming_callback<F>(&mut self, _: F)where
F: UnitType + Fn(&mut HandleScope<'_>, Local<'_, Value>, WasmStreaming),
pub fn set_wasm_streaming_callback<F>(&mut self, _: F)where
F: UnitType + Fn(&mut HandleScope<'_>, Local<'_, Value>, WasmStreaming),
Embedder injection point for WebAssembly.compileStreaming(source).
The expectation is that the embedder sets it at most once.
The callback receives the source argument (string, Promise, etc.) and an instance of WasmStreaming. The WasmStreaming instance can outlive the callback and is used to feed data chunks to V8 asynchronously.
sourcepub fn has_pending_background_tasks(&self) -> bool
pub fn has_pending_background_tasks(&self) -> bool
Returns true if there is ongoing background work within V8 that will eventually post a foreground task, like asynchronous WebAssembly compilation.
sourcepub fn take_heap_snapshot<F>(&mut self, callback: F)where
F: FnMut(&[u8]) -> bool,
pub fn take_heap_snapshot<F>(&mut self, callback: F)where
F: FnMut(&[u8]) -> bool,
Take a heap snapshot. The callback is invoked one or more times with byte slices containing the snapshot serialized as JSON. It’s the callback’s responsibility to reassemble them into a single document, e.g., by writing them to a file. Note that Chrome DevTools refuses to load snapshots without a .heapsnapshot suffix.
sourcepub fn set_default_context(&mut self, context: Local<'_, Context>)
pub fn set_default_context(&mut self, context: Local<'_, Context>)
Set the default context to be included in the snapshot blob. The snapshot will not contain the global proxy, and we expect one or a global object template to create one, to be provided upon deserialization.
Panics
Panics if the isolate was not created using Isolate::snapshot_creator
sourcepub fn add_context(&mut self, context: Local<'_, Context>) -> usize
pub fn add_context(&mut self, context: Local<'_, Context>) -> usize
Add additional context to be included in the snapshot blob. The snapshot will include the global proxy.
Returns the index of the context in the snapshot blob.
Panics
Panics if the isolate was not created using Isolate::snapshot_creator
sourcepub fn add_isolate_data<T>(&mut self, data: Local<'_, T>) -> usizewhere
for<'l> Local<'l, T>: Into<Local<'l, Data>>,
pub fn add_isolate_data<T>(&mut self, data: Local<'_, T>) -> usizewhere
for<'l> Local<'l, T>: Into<Local<'l, Data>>,
Attach arbitrary v8::Data to the isolate snapshot, which can be
retrieved via HandleScope::get_context_data_from_snapshot_once() after
deserialization. This data does not survive when a new snapshot is created
from an existing snapshot.
Panics
Panics if the isolate was not created using Isolate::snapshot_creator
sourcepub fn add_context_data<T>(
&mut self,
context: Local<'_, Context>,
data: Local<'_, T>
) -> usizewhere
for<'l> Local<'l, T>: Into<Local<'l, Data>>,
pub fn add_context_data<T>(
&mut self,
context: Local<'_, Context>,
data: Local<'_, T>
) -> usizewhere
for<'l> Local<'l, T>: Into<Local<'l, Data>>,
Attach arbitrary v8::Data to the context snapshot, which can be
retrieved via HandleScope::get_context_data_from_snapshot_once() after
deserialization. This data does not survive when a new snapshot is
created from an existing snapshot.
Panics
Panics if the isolate was not created using Isolate::snapshot_creator