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// Copyright 2019-2020 the Deno authors. All rights reserved. MIT license. use crate::isolate_create_params::raw; use crate::isolate_create_params::CreateParams; use crate::promise::PromiseRejectMessage; use crate::support::Opaque; use crate::Context; use crate::Function; use crate::InIsolate; use crate::Local; use crate::Message; use crate::Module; use crate::Object; use crate::Promise; use crate::ScriptOrModule; use crate::String; use crate::Value; use std::any::Any; use std::any::TypeId; use std::cell::{Ref, RefCell, RefMut}; use std::collections::HashMap; use std::ffi::c_void; use std::ops::Deref; use std::ops::DerefMut; use std::ptr::null_mut; use std::ptr::NonNull; use std::sync::Arc; use std::sync::Mutex; pub type MessageCallback = extern "C" fn(Local<Message>, Local<Value>); pub type PromiseRejectCallback = extern "C" fn(PromiseRejectMessage); /// HostInitializeImportMetaObjectCallback is called the first time import.meta /// is accessed for a module. Subsequent access will reuse the same value. /// /// The method combines two implementation-defined abstract operations into one: /// HostGetImportMetaProperties and HostFinalizeImportMeta. /// /// The embedder should use v8::Object::CreateDataProperty to add properties on /// the meta object. pub type HostInitializeImportMetaObjectCallback = extern "C" fn(Local<Context>, Local<Module>, Local<Object>); /// HostImportModuleDynamicallyCallback is called when we require the /// embedder to load a module. This is used as part of the dynamic /// import syntax. /// /// The referrer contains metadata about the script/module that calls /// import. /// /// The specifier is the name of the module that should be imported. /// /// The embedder must compile, instantiate, evaluate the Module, and /// obtain it's namespace object. /// /// The Promise returned from this function is forwarded to userland /// JavaScript. The embedder must resolve this promise with the module /// namespace object. In case of an exception, the embedder must reject /// this promise with the exception. If the promise creation itself /// fails (e.g. due to stack overflow), the embedder must propagate /// that exception by returning an empty MaybeLocal. pub type HostImportModuleDynamicallyCallback = extern "C" fn( Local<Context>, Local<ScriptOrModule>, Local<String>, ) -> *mut Promise; pub type InterruptCallback = extern "C" fn(isolate: &mut Isolate, data: *mut c_void); extern "C" { fn v8__Isolate__New(params: *const raw::CreateParams) -> *mut Isolate; fn v8__Isolate__Dispose(this: *mut Isolate); fn v8__Isolate__SetData(this: *mut Isolate, slot: u32, data: *mut c_void); fn v8__Isolate__GetData(this: *const Isolate, slot: u32) -> *mut c_void; fn v8__Isolate__GetNumberOfDataSlots(this: *const Isolate) -> u32; fn v8__Isolate__Enter(this: *mut Isolate); fn v8__Isolate__Exit(this: *mut Isolate); fn v8__Isolate__SetCaptureStackTraceForUncaughtExceptions( this: *mut Isolate, caputre: bool, frame_limit: i32, ); fn v8__Isolate__AddMessageListener( isolate: *mut Isolate, callback: MessageCallback, ) -> bool; fn v8__Isolate__SetPromiseRejectCallback( isolate: *mut Isolate, callback: PromiseRejectCallback, ); fn v8__Isolate__SetHostInitializeImportMetaObjectCallback( isolate: *mut Isolate, callback: HostInitializeImportMetaObjectCallback, ); fn v8__Isolate__SetHostImportModuleDynamicallyCallback( isolate: *mut Isolate, callback: HostImportModuleDynamicallyCallback, ); fn v8__Isolate__RequestInterrupt( isolate: *const Isolate, callback: InterruptCallback, data: *mut c_void, ); fn v8__Isolate__ThrowException( isolate: *mut Isolate, exception: *const Value, ) -> *const Value; fn v8__Isolate__TerminateExecution(isolate: *const Isolate); fn v8__Isolate__IsExecutionTerminating(isolate: *const Isolate) -> bool; fn v8__Isolate__CancelTerminateExecution(isolate: *const Isolate); fn v8__Isolate__RunMicrotasks(isolate: *mut Isolate); fn v8__Isolate__EnqueueMicrotask( isolate: *mut Isolate, function: *const Function, ); fn v8__HeapProfiler__TakeHeapSnapshot( isolate: *mut Isolate, callback: extern "C" fn(*mut c_void, *const u8, usize) -> bool, arg: *mut c_void, ); } #[repr(C)] /// Isolate represents an isolated instance of the V8 engine. V8 isolates have /// completely separate states. Objects from one isolate must not be used in /// other isolates. The embedder can create multiple isolates and use them in /// parallel in multiple threads. An isolate can be entered by at most one /// thread at any given time. The Locker/Unlocker API must be used to /// synchronize. pub struct Isolate(Opaque); impl Isolate { /// Creates a new isolate. Does not change the currently entered /// isolate. /// /// When an isolate is no longer used its resources should be freed /// by calling V8::dispose(). Using the delete operator is not allowed. /// /// V8::initialize() must have run prior to this. #[allow(clippy::new_ret_no_self)] pub fn new(params: CreateParams) -> OwnedIsolate { crate::V8::assert_initialized(); let (raw_create_params, create_param_allocations) = params.finalize(); let cxx_isolate = unsafe { v8__Isolate__New(&raw_create_params) }; let mut owned_isolate = OwnedIsolate::new(cxx_isolate); owned_isolate.create_annex(create_param_allocations); owned_isolate } /// Initial configuration parameters for a new Isolate. pub fn create_params() -> CreateParams { CreateParams::default() } pub fn thread_safe_handle(&mut self) -> IsolateHandle { IsolateHandle::new(self) } fn create_annex(&mut self, create_param_allocations: Box<dyn Any>) { let annex_arc = Arc::new(IsolateAnnex::new(self, create_param_allocations)); let annex_ptr = Arc::into_raw(annex_arc); unsafe { v8__Isolate__SetData(self, 0, annex_ptr as *mut c_void) } } fn get_annex(&self) -> &IsolateAnnex { unsafe { &*(v8__Isolate__GetData(self, 0) as *const _ as *const IsolateAnnex) } } fn get_annex_mut(&mut self) -> &mut IsolateAnnex { unsafe { &mut *(v8__Isolate__GetData(self, 0) as *mut IsolateAnnex) } } fn get_annex_arc(&self) -> Arc<IsolateAnnex> { let annex_ptr = self.get_annex(); let annex_arc = unsafe { Arc::from_raw(annex_ptr) }; Arc::into_raw(annex_arc.clone()); annex_arc } /// Associate embedder-specific data with the isolate. |slot| has to be /// between 0 and GetNumberOfDataSlots() - 1. pub unsafe fn set_data(&mut self, slot: u32, ptr: *mut c_void) { v8__Isolate__SetData(self, slot + 1, ptr) } /// Retrieve embedder-specific data from the isolate. /// Returns NULL if SetData has never been called for the given |slot|. pub fn get_data(&self, slot: u32) -> *mut c_void { unsafe { v8__Isolate__GetData(self, slot + 1) } } /// Returns the maximum number of available embedder data slots. Valid slots /// are in the range of 0 - GetNumberOfDataSlots() - 1. pub fn get_number_of_data_slots(&self) -> u32 { unsafe { v8__Isolate__GetNumberOfDataSlots(self) - 1 } } /// Safe alternative to Isolate::get_data /// /// Warning: will be renamed to get_data_mut() after original unsafe version /// is removed. pub fn get_slot_mut<T: 'static>(&self) -> Option<RefMut<T>> { let cell = self.get_annex().slots.get(&TypeId::of::<T>())?; let ref_mut = cell.try_borrow_mut().ok()?; let ref_mut = RefMut::map(ref_mut, |box_any| { let mut_any = &mut **box_any; Any::downcast_mut::<T>(mut_any).unwrap() }); Some(ref_mut) } /// Safe alternative to Isolate::get_data /// /// Warning: will be renamed to get_data() after original unsafe version is /// removed. pub fn get_slot<T: 'static>(&self) -> Option<Ref<T>> { let cell = self.get_annex().slots.get(&TypeId::of::<T>())?; let r = cell.try_borrow().ok()?; Some(Ref::map(r, |box_any| { let a = &**box_any; Any::downcast_ref::<T>(a).unwrap() })) } /// Safe alternative to Isolate::set_data /// /// 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. /// /// Warning: will be renamed to set_data() after original unsafe version is /// removed. pub fn set_slot<T: 'static>(&mut self, value: T) -> bool { self .get_annex_mut() .slots .insert(Any::type_id(&value), RefCell::new(Box::new(value))) .is_none() } /// 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. pub(crate) fn enter(&mut self) { unsafe { v8__Isolate__Enter(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(). pub(crate) fn exit(&mut self) { unsafe { v8__Isolate__Exit(self) } } /// Tells V8 to capture current stack trace when uncaught exception occurs /// and report it to the message listeners. The option is off by default. pub fn set_capture_stack_trace_for_uncaught_exceptions( &mut self, capture: bool, frame_limit: i32, ) { unsafe { v8__Isolate__SetCaptureStackTraceForUncaughtExceptions( self, capture, frame_limit, ) } } /// 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. pub fn add_message_listener(&mut self, callback: MessageCallback) -> bool { unsafe { v8__Isolate__AddMessageListener(self, callback) } } /// 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_promise_reject_callback( &mut self, callback: PromiseRejectCallback, ) { unsafe { v8__Isolate__SetPromiseRejectCallback(self, callback) } } /// This specifies the callback called by the upcoming importa.meta /// language feature to retrieve host-defined meta data for a module. pub fn set_host_initialize_import_meta_object_callback( &mut self, callback: HostInitializeImportMetaObjectCallback, ) { unsafe { v8__Isolate__SetHostInitializeImportMetaObjectCallback(self, callback) } } /// This specifies the callback called by the upcoming dynamic /// import() language feature to load modules. pub fn set_host_import_module_dynamically_callback( &mut self, callback: HostImportModuleDynamicallyCallback, ) { unsafe { v8__Isolate__SetHostImportModuleDynamicallyCallback(self, callback) } } /// 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. pub fn throw_exception<'sc>( &mut self, exception: Local<Value>, ) -> Local<'sc, Value> { unsafe { let ptr = v8__Isolate__ThrowException(self, &*exception); Local::from_raw(ptr).unwrap() } } /// Runs the default MicrotaskQueue until it gets empty. /// Any exceptions thrown by microtask callbacks are swallowed. pub fn run_microtasks(&mut self) { unsafe { v8__Isolate__RunMicrotasks(self) } } /// Enqueues the callback to the default MicrotaskQueue pub fn enqueue_microtask(&mut self, microtask: Local<Function>) { unsafe { v8__Isolate__EnqueueMicrotask(self, &*microtask) } } /// Disposes the isolate. The isolate must not be entered by any /// thread to be disposable. unsafe fn dispose(&mut self) { let annex = self.get_annex_mut(); // Set the `isolate` pointer inside the annex struct to null, so any // IsolateHandle that outlives the isolate will know that it can't call // methods on the isolate. { let _lock = annex.isolate_mutex.lock().unwrap(); annex.isolate = null_mut(); } // Clear slots and drop owned objects that were taken out of `CreateParams`. annex.create_param_allocations = Box::new(()); annex.slots.clear(); // Subtract one from the Arc<IsolateAnnex> reference count. Arc::from_raw(annex); self.set_data(0, null_mut()); // No test case in rusty_v8 show this, but there have been situations in // deno where dropping Annex before the states causes a segfault. v8__Isolate__Dispose(self) } /// 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. pub fn take_heap_snapshot<F>(&mut self, mut callback: F) where F: FnMut(&[u8]) -> bool, { extern "C" fn trampoline<F>( arg: *mut c_void, data: *const u8, size: usize, ) -> bool where F: FnMut(&[u8]) -> bool, { let p = arg as *mut F; let callback = unsafe { &mut *p }; let slice = unsafe { std::slice::from_raw_parts(data, size) }; callback(slice) } let arg = &mut callback as *mut F as *mut c_void; unsafe { v8__HeapProfiler__TakeHeapSnapshot(self, trampoline::<F>, arg) } } } pub(crate) struct IsolateAnnex { create_param_allocations: Box<dyn Any>, slots: HashMap<TypeId, RefCell<Box<dyn Any>>>, // The `isolate` and `isolate_mutex` fields are there so an `IsolateHandle` // (which may outlive the isolate itself) can determine whether the isolate is // still alive, and if so, get a reference to it. Safety rules: // - The 'main thread' must lock the mutex and reset `isolate` to null just // before the isolate is disposed. // - Any other thread must lock the mutex while it's reading/using the // `isolate` pointer. isolate: *mut Isolate, isolate_mutex: Mutex<()>, } impl IsolateAnnex { fn new( isolate: &mut Isolate, create_param_allocations: Box<dyn Any>, ) -> Self { Self { create_param_allocations, slots: HashMap::new(), isolate, isolate_mutex: Mutex::new(()), } } } /// IsolateHandle is a thread-safe reference to an Isolate. It's main use is to /// terminate execution of a running isolate from another thread. /// /// It is created with Isolate::thread_safe_handle(). /// /// IsolateHandle is Cloneable, Send, and Sync. #[derive(Clone)] pub struct IsolateHandle(Arc<IsolateAnnex>); unsafe impl Send for IsolateHandle {} unsafe impl Sync for IsolateHandle {} impl IsolateHandle { // This function is marked unsafe because it must be called only with either // IsolateAnnex::mutex locked, or from the main thread associated with the V8 // isolate. pub(crate) unsafe fn get_isolate_ptr(&self) -> *mut Isolate { self.0.isolate } fn new(isolate: &mut Isolate) -> Self { Self(isolate.get_annex_arc()) } /// Forcefully terminate the current thread of JavaScript execution /// in the given isolate. /// /// This method can be used by any thread even if that thread has not /// acquired the V8 lock with a Locker object. /// /// Returns false if Isolate was already destroyed. pub fn terminate_execution(&self) -> bool { let _lock = self.0.isolate_mutex.lock().unwrap(); if self.0.isolate.is_null() { false } else { unsafe { v8__Isolate__TerminateExecution(self.0.isolate) }; true } } /// Resume execution capability in the given isolate, whose execution /// was previously forcefully terminated using TerminateExecution(). /// /// When execution is forcefully terminated using TerminateExecution(), /// the isolate can not resume execution until all JavaScript frames /// have propagated the uncatchable exception which is generated. This /// method allows the program embedding the engine to handle the /// termination event and resume execution capability, even if /// JavaScript frames remain on the stack. /// /// This method can be used by any thread even if that thread has not /// acquired the V8 lock with a Locker object. /// /// Returns false if Isolate was already destroyed. pub fn cancel_terminate_execution(&self) -> bool { let _lock = self.0.isolate_mutex.lock().unwrap(); if self.0.isolate.is_null() { false } else { unsafe { v8__Isolate__CancelTerminateExecution(self.0.isolate) }; true } } /// Is V8 terminating JavaScript execution. /// /// Returns true if JavaScript execution is currently terminating /// because of a call to TerminateExecution. In that case there are /// still JavaScript frames on the stack and the termination /// exception is still active. /// /// Returns false if Isolate was already destroyed. pub fn is_execution_terminating(&self) -> bool { let _lock = self.0.isolate_mutex.lock().unwrap(); if self.0.isolate.is_null() { false } else { unsafe { v8__Isolate__IsExecutionTerminating(self.0.isolate) } } } /// Request V8 to interrupt long running JavaScript code and invoke /// the given |callback| passing the given |data| to it. After |callback| /// returns control will be returned to the JavaScript code. /// There may be a number of interrupt requests in flight. /// Can be called from another thread without acquiring a |Locker|. /// Registered |callback| must not reenter interrupted Isolate. /// /// Returns false if Isolate was already destroyed. // Clippy warns that this method is dereferencing a raw pointer, but it is // not: https://github.com/rust-lang/rust-clippy/issues/3045 #[allow(clippy::not_unsafe_ptr_arg_deref)] pub fn request_interrupt( &self, callback: InterruptCallback, data: *mut c_void, ) -> bool { let _lock = self.0.isolate_mutex.lock().unwrap(); if self.0.isolate.is_null() { false } else { unsafe { v8__Isolate__RequestInterrupt(self.0.isolate, callback, data) }; true } } } /// Same as Isolate but gets disposed when it goes out of scope. pub struct OwnedIsolate { cxx_isolate: NonNull<Isolate>, } impl OwnedIsolate { pub(crate) fn new(cxx_isolate: *mut Isolate) -> Self { let cxx_isolate = NonNull::new(cxx_isolate).unwrap(); Self { cxx_isolate } } } impl InIsolate for OwnedIsolate { fn isolate(&mut self) -> &mut Isolate { self.deref_mut() } } impl Drop for OwnedIsolate { fn drop(&mut self) { unsafe { self.cxx_isolate.as_mut().dispose() } } } impl Deref for OwnedIsolate { type Target = Isolate; fn deref(&self) -> &Self::Target { unsafe { self.cxx_isolate.as_ref() } } } impl DerefMut for OwnedIsolate { fn deref_mut(&mut self) -> &mut Self::Target { unsafe { self.cxx_isolate.as_mut() } } }