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denoland-deno/core/runtime/jsruntime.rs
Matt Mastracci 88e6e9c1e6
refactor(core): some runtime methods should live on the module map (#19502)
A few easy migrations of module code from the runtime to the module map.

The module map already has a few places where it needs a handle scope,
so we're not coupling it any further with the v8 runtime.

`init_runtime_module_map` is replaced with an option to reduce API
surface of JsRuntime.

`module_resolve_callback` now lives in the `ModuleMap` and we use a
annex data to avoid having to go through the `Rc<RefCell<...>>` stored
in the `JsRuntime`'s isolate.
2023-06-14 16:45:59 +00:00

2313 lines
76 KiB
Rust

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
use super::bindings;
use super::jsrealm::JsRealmInner;
use super::snapshot_util;
use crate::error::exception_to_err_result;
use crate::error::generic_error;
use crate::error::to_v8_type_error;
use crate::error::GetErrorClassFn;
use crate::error::JsError;
use crate::extensions::OpDecl;
use crate::extensions::OpEventLoopFn;
use crate::inspector::JsRuntimeInspector;
use crate::module_specifier::ModuleSpecifier;
use crate::modules::AssertedModuleType;
use crate::modules::ExtModuleLoader;
use crate::modules::ExtModuleLoaderCb;
use crate::modules::ModuleCode;
use crate::modules::ModuleError;
use crate::modules::ModuleId;
use crate::modules::ModuleLoadId;
use crate::modules::ModuleLoader;
use crate::modules::ModuleMap;
use crate::ops::*;
use crate::runtime::ContextState;
use crate::runtime::JsRealm;
use crate::source_map::SourceMapCache;
use crate::source_map::SourceMapGetter;
use crate::Extension;
use crate::NoopModuleLoader;
use crate::OpMiddlewareFn;
use crate::OpResult;
use crate::OpState;
use crate::V8_WRAPPER_OBJECT_INDEX;
use crate::V8_WRAPPER_TYPE_INDEX;
use anyhow::Context as AnyhowContext;
use anyhow::Error;
use futures::channel::oneshot;
use futures::future::poll_fn;
use futures::future::Future;
use futures::stream::StreamExt;
use smallvec::SmallVec;
use std::any::Any;
use std::cell::RefCell;
use std::collections::HashMap;
use std::ffi::c_void;
use std::mem::ManuallyDrop;
use std::ops::Deref;
use std::ops::DerefMut;
use std::option::Option;
use std::rc::Rc;
use std::sync::atomic::AtomicBool;
use std::sync::atomic::Ordering;
use std::sync::Arc;
use std::sync::Mutex;
use std::sync::Once;
use std::task::Context;
use std::task::Poll;
const STATE_DATA_OFFSET: u32 = 0;
const MODULE_MAP_DATA_OFFSET: u32 = 1;
pub enum Snapshot {
Static(&'static [u8]),
JustCreated(v8::StartupData),
Boxed(Box<[u8]>),
}
/// Objects that need to live as long as the isolate
#[derive(Default)]
pub(crate) struct IsolateAllocations {
pub(crate) near_heap_limit_callback_data:
Option<(Box<RefCell<dyn Any>>, v8::NearHeapLimitCallback)>,
}
/// ManuallyDrop<Rc<...>> is clone, but it returns a ManuallyDrop<Rc<...>> which is a massive
/// memory-leak footgun.
pub(crate) struct ManuallyDropRc<T>(ManuallyDrop<Rc<T>>);
impl<T> ManuallyDropRc<T> {
pub fn clone(&self) -> Rc<T> {
self.0.deref().clone()
}
}
impl<T> Deref for ManuallyDropRc<T> {
type Target = Rc<T>;
fn deref(&self) -> &Self::Target {
self.0.deref()
}
}
impl<T> DerefMut for ManuallyDropRc<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
self.0.deref_mut()
}
}
/// This struct contains the [`JsRuntimeState`] and [`v8::OwnedIsolate`] that are required
/// to do an orderly shutdown of V8. We keep these in a separate struct to allow us to control
/// the destruction more closely, as snapshots require the isolate to be destroyed by the
/// snapshot process, not the destructor.
///
/// The way rusty_v8 works w/snapshots is that the [`v8::OwnedIsolate`] gets consumed by a
/// [`v8::snapshot::SnapshotCreator`] that is stored in its annex. It's a bit awkward, because this
/// means we cannot let it drop (because we don't have it after a snapshot). On top of that, we have
/// to consume it in the snapshot creator because otherwise it panics.
///
/// This inner struct allows us to let the outer JsRuntime drop normally without a Drop impl, while we
/// control dropping more closely here using ManuallyDrop.
pub(crate) struct InnerIsolateState {
will_snapshot: bool,
pub(crate) state: ManuallyDropRc<RefCell<JsRuntimeState>>,
v8_isolate: ManuallyDrop<v8::OwnedIsolate>,
}
impl InnerIsolateState {
/// Clean out the opstate and take the inspector to prevent the inspector from getting destroyed
/// after we've torn down the contexts. If the inspector is not correctly torn down, random crashes
/// happen in tests (and possibly for users using the inspector).
pub fn prepare_for_cleanup(&mut self) {
let mut state = self.state.borrow_mut();
let inspector = state.inspector.take();
state.op_state.borrow_mut().clear();
if let Some(inspector) = inspector {
assert_eq!(
Rc::strong_count(&inspector),
1,
"The inspector must be dropped before the runtime"
);
}
}
pub fn cleanup(&mut self) {
self.prepare_for_cleanup();
let state_ptr = self.v8_isolate.get_data(STATE_DATA_OFFSET);
// SAFETY: We are sure that it's a valid pointer for whole lifetime of
// the runtime.
_ = unsafe { Rc::from_raw(state_ptr as *const RefCell<JsRuntimeState>) };
let module_map_ptr = self.v8_isolate.get_data(MODULE_MAP_DATA_OFFSET);
// SAFETY: We are sure that it's a valid pointer for whole lifetime of
// the runtime.
_ = unsafe { Rc::from_raw(module_map_ptr as *const RefCell<ModuleMap>) };
self.state.borrow_mut().destroy_all_realms();
debug_assert_eq!(Rc::strong_count(&self.state), 1);
}
pub fn prepare_for_snapshot(mut self) -> v8::OwnedIsolate {
self.cleanup();
// SAFETY: We're copying out of self and then immediately forgetting self
let (state, isolate) = unsafe {
(
ManuallyDrop::take(&mut self.state.0),
ManuallyDrop::take(&mut self.v8_isolate),
)
};
std::mem::forget(self);
drop(state);
isolate
}
}
impl Drop for InnerIsolateState {
fn drop(&mut self) {
self.cleanup();
// SAFETY: We gotta drop these
unsafe {
ManuallyDrop::drop(&mut self.state.0);
if self.will_snapshot {
// Create the snapshot and just drop it.
eprintln!("WARNING: v8::OwnedIsolate for snapshot was leaked");
} else {
ManuallyDrop::drop(&mut self.v8_isolate);
}
}
}
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub(crate) enum InitMode {
/// We have no snapshot -- this is a pristine context.
New,
/// We are using a snapshot, thus certain initialization steps are skipped.
FromSnapshot,
}
impl InitMode {
fn from_options(options: &RuntimeOptions) -> Self {
match options.startup_snapshot {
None => Self::New,
Some(_) => Self::FromSnapshot,
}
}
}
/// A single execution context of JavaScript. Corresponds roughly to the "Web
/// Worker" concept in the DOM.
////
/// The JsRuntime future completes when there is an error or when all
/// pending ops have completed.
///
/// Use [`JsRuntimeForSnapshot`] to be able to create a snapshot.
pub struct JsRuntime {
pub(crate) inner: InnerIsolateState,
pub(crate) module_map: Rc<RefCell<ModuleMap>>,
pub(crate) allocations: IsolateAllocations,
extensions: Vec<Extension>,
event_loop_middlewares: Vec<Box<OpEventLoopFn>>,
init_mode: InitMode,
// Marks if this is considered the top-level runtime. Used only be inspector.
is_main: bool,
}
/// The runtime type used for snapshot creation.
pub struct JsRuntimeForSnapshot(JsRuntime);
impl Deref for JsRuntimeForSnapshot {
type Target = JsRuntime;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for JsRuntimeForSnapshot {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
pub(crate) struct DynImportModEvaluate {
load_id: ModuleLoadId,
module_id: ModuleId,
promise: v8::Global<v8::Promise>,
module: v8::Global<v8::Module>,
}
pub(crate) struct ModEvaluate {
pub(crate) promise: Option<v8::Global<v8::Promise>>,
pub(crate) has_evaluated: bool,
pub(crate) handled_promise_rejections: Vec<v8::Global<v8::Promise>>,
sender: oneshot::Sender<Result<(), Error>>,
}
pub struct CrossIsolateStore<T>(Arc<Mutex<CrossIsolateStoreInner<T>>>);
struct CrossIsolateStoreInner<T> {
map: HashMap<u32, T>,
last_id: u32,
}
impl<T> CrossIsolateStore<T> {
pub(crate) fn insert(&self, value: T) -> u32 {
let mut store = self.0.lock().unwrap();
let last_id = store.last_id;
store.map.insert(last_id, value);
store.last_id += 1;
last_id
}
pub(crate) fn take(&self, id: u32) -> Option<T> {
let mut store = self.0.lock().unwrap();
store.map.remove(&id)
}
}
impl<T> Default for CrossIsolateStore<T> {
fn default() -> Self {
CrossIsolateStore(Arc::new(Mutex::new(CrossIsolateStoreInner {
map: Default::default(),
last_id: 0,
})))
}
}
impl<T> Clone for CrossIsolateStore<T> {
fn clone(&self) -> Self {
Self(self.0.clone())
}
}
pub type SharedArrayBufferStore =
CrossIsolateStore<v8::SharedRef<v8::BackingStore>>;
pub type CompiledWasmModuleStore = CrossIsolateStore<v8::CompiledWasmModule>;
/// Internal state for JsRuntime which is stored in one of v8::Isolate's
/// embedder slots.
pub struct JsRuntimeState {
global_realm: Option<JsRealm>,
known_realms: Vec<JsRealmInner>,
pub(crate) has_tick_scheduled: bool,
pub(crate) pending_dyn_mod_evaluate: Vec<DynImportModEvaluate>,
pub(crate) pending_mod_evaluate: Option<ModEvaluate>,
/// A counter used to delay our dynamic import deadlock detection by one spin
/// of the event loop.
dyn_module_evaluate_idle_counter: u32,
pub(crate) source_map_getter: Option<Rc<Box<dyn SourceMapGetter>>>,
pub(crate) source_map_cache: Rc<RefCell<SourceMapCache>>,
pub(crate) op_state: Rc<RefCell<OpState>>,
pub(crate) shared_array_buffer_store: Option<SharedArrayBufferStore>,
pub(crate) compiled_wasm_module_store: Option<CompiledWasmModuleStore>,
/// The error that was passed to an `op_dispatch_exception` call.
/// It will be retrieved by `exception_to_err_result` and used as an error
/// instead of any other exceptions.
// TODO(nayeemrmn): This is polled in `exception_to_err_result()` which is
// flimsy. Try to poll it similarly to `pending_promise_rejections`.
pub(crate) dispatched_exception: Option<v8::Global<v8::Value>>,
pub(crate) inspector: Option<Rc<RefCell<JsRuntimeInspector>>>,
}
impl JsRuntimeState {
pub(crate) fn destroy_all_realms(&mut self) {
self.global_realm.take();
for realm in self.known_realms.drain(..) {
realm.destroy()
}
}
pub(crate) fn remove_realm(
&mut self,
realm_context: &Rc<v8::Global<v8::Context>>,
) {
self
.known_realms
.retain(|realm| !realm.is_same(realm_context));
}
}
fn v8_init(
v8_platform: Option<v8::SharedRef<v8::Platform>>,
predictable: bool,
) {
// Include 10MB ICU data file.
#[repr(C, align(16))]
struct IcuData([u8; 10541264]);
static ICU_DATA: IcuData = IcuData(*include_bytes!("icudtl.dat"));
v8::icu::set_common_data_72(&ICU_DATA.0).unwrap();
let flags = concat!(
" --wasm-test-streaming",
" --harmony-import-assertions",
" --no-validate-asm",
" --turbo_fast_api_calls",
" --harmony-change-array-by-copy",
);
if predictable {
v8::V8::set_flags_from_string(&format!(
"{}{}",
flags, " --predictable --random-seed=42"
));
} else {
v8::V8::set_flags_from_string(flags);
}
let v8_platform = v8_platform
.unwrap_or_else(|| v8::new_default_platform(0, false).make_shared());
v8::V8::initialize_platform(v8_platform);
v8::V8::initialize();
}
#[derive(Default)]
pub struct RuntimeOptions {
/// Source map reference for errors.
pub source_map_getter: Option<Box<dyn SourceMapGetter>>,
/// Allows to map error type to a string "class" used to represent
/// error in JavaScript.
pub get_error_class_fn: Option<GetErrorClassFn>,
/// Implementation of `ModuleLoader` which will be
/// called when V8 requests to load ES modules.
///
/// If not provided runtime will error if code being
/// executed tries to load modules.
pub module_loader: Option<Rc<dyn ModuleLoader>>,
/// JsRuntime extensions, not to be confused with ES modules.
/// Only ops registered by extensions will be initialized. If you need
/// to execute JS code from extensions, pass source files in `js` or `esm`
/// option on `ExtensionBuilder`.
///
/// If you are creating a runtime from a snapshot take care not to include
/// JavaScript sources in the extensions.
pub extensions: Vec<Extension>,
/// If provided, the module map will be cleared and left only with the specifiers
/// in this list, with the new names provided. If not provided, the module map is
/// left intact.
pub rename_modules: Option<Vec<(&'static str, &'static str)>>,
/// V8 snapshot that should be loaded on startup.
pub startup_snapshot: Option<Snapshot>,
/// Isolate creation parameters.
pub create_params: Option<v8::CreateParams>,
/// V8 platform instance to use. Used when Deno initializes V8
/// (which it only does once), otherwise it's silenty dropped.
pub v8_platform: Option<v8::SharedRef<v8::Platform>>,
/// The store to use for transferring SharedArrayBuffers between isolates.
/// If multiple isolates should have the possibility of sharing
/// SharedArrayBuffers, they should use the same [SharedArrayBufferStore]. If
/// no [SharedArrayBufferStore] is specified, SharedArrayBuffer can not be
/// serialized.
pub shared_array_buffer_store: Option<SharedArrayBufferStore>,
/// The store to use for transferring `WebAssembly.Module` objects between
/// isolates.
/// If multiple isolates should have the possibility of sharing
/// `WebAssembly.Module` objects, they should use the same
/// [CompiledWasmModuleStore]. If no [CompiledWasmModuleStore] is specified,
/// `WebAssembly.Module` objects cannot be serialized.
pub compiled_wasm_module_store: Option<CompiledWasmModuleStore>,
/// Start inspector instance to allow debuggers to connect.
pub inspector: bool,
/// Describe if this is the main runtime instance, used by debuggers in some
/// situation - like disconnecting when program finishes running.
pub is_main: bool,
}
#[derive(Default)]
pub struct RuntimeSnapshotOptions {
/// An optional callback that will be called for each module that is loaded
/// during snapshotting. This callback can be used to transpile source on the
/// fly, during snapshotting, eg. to transpile TypeScript to JavaScript.
pub snapshot_module_load_cb: Option<ExtModuleLoaderCb>,
}
impl JsRuntime {
/// Only constructor, configuration is done through `options`.
pub fn new(mut options: RuntimeOptions) -> JsRuntime {
JsRuntime::init_v8(options.v8_platform.take(), cfg!(test));
JsRuntime::new_inner(options, false, None)
}
pub(crate) fn state_from(
isolate: &v8::Isolate,
) -> Rc<RefCell<JsRuntimeState>> {
let state_ptr = isolate.get_data(STATE_DATA_OFFSET);
let state_rc =
// SAFETY: We are sure that it's a valid pointer for whole lifetime of
// the runtime.
unsafe { Rc::from_raw(state_ptr as *const RefCell<JsRuntimeState>) };
let state = state_rc.clone();
std::mem::forget(state_rc);
state
}
pub(crate) fn module_map_from(
isolate: &v8::Isolate,
) -> Rc<RefCell<ModuleMap>> {
let module_map_ptr = isolate.get_data(MODULE_MAP_DATA_OFFSET);
let module_map_rc =
// SAFETY: We are sure that it's a valid pointer for whole lifetime of
// the runtime.
unsafe { Rc::from_raw(module_map_ptr as *const RefCell<ModuleMap>) };
let module_map = module_map_rc.clone();
std::mem::forget(module_map_rc);
module_map
}
pub(crate) fn event_loop_pending_state_from_scope(
scope: &mut v8::HandleScope,
) -> EventLoopPendingState {
let state = JsRuntime::state_from(scope);
let module_map = JsRuntime::module_map_from(scope);
let state = EventLoopPendingState::new(
scope,
&mut state.borrow_mut(),
&module_map.borrow(),
);
state
}
fn init_v8(
v8_platform: Option<v8::SharedRef<v8::Platform>>,
predictable: bool,
) {
static DENO_INIT: Once = Once::new();
static DENO_PREDICTABLE: AtomicBool = AtomicBool::new(false);
static DENO_PREDICTABLE_SET: AtomicBool = AtomicBool::new(false);
if DENO_PREDICTABLE_SET.load(Ordering::SeqCst) {
let current = DENO_PREDICTABLE.load(Ordering::SeqCst);
assert_eq!(current, predictable, "V8 may only be initialized once in either snapshotting or non-snapshotting mode. Either snapshotting or non-snapshotting mode may be used in a single process, not both.");
DENO_PREDICTABLE_SET.store(true, Ordering::SeqCst);
DENO_PREDICTABLE.store(predictable, Ordering::SeqCst);
}
DENO_INIT.call_once(move || v8_init(v8_platform, predictable));
}
fn new_inner(
mut options: RuntimeOptions,
will_snapshot: bool,
maybe_load_callback: Option<ExtModuleLoaderCb>,
) -> JsRuntime {
let init_mode = InitMode::from_options(&options);
let (op_state, ops) = Self::create_opstate(&mut options, init_mode);
let op_state = Rc::new(RefCell::new(op_state));
// Collect event-loop middleware
let mut event_loop_middlewares =
Vec::with_capacity(options.extensions.len());
for extension in &mut options.extensions {
if let Some(middleware) = extension.init_event_loop_middleware() {
event_loop_middlewares.push(middleware);
}
}
let align = std::mem::align_of::<usize>();
let layout = std::alloc::Layout::from_size_align(
std::mem::size_of::<*mut v8::OwnedIsolate>(),
align,
)
.unwrap();
assert!(layout.size() > 0);
let isolate_ptr: *mut v8::OwnedIsolate =
// SAFETY: we just asserted that layout has non-0 size.
unsafe { std::alloc::alloc(layout) as *mut _ };
let state_rc = Rc::new(RefCell::new(JsRuntimeState {
pending_dyn_mod_evaluate: vec![],
pending_mod_evaluate: None,
dyn_module_evaluate_idle_counter: 0,
has_tick_scheduled: false,
source_map_getter: options.source_map_getter.map(Rc::new),
source_map_cache: Default::default(),
shared_array_buffer_store: options.shared_array_buffer_store,
compiled_wasm_module_store: options.compiled_wasm_module_store,
op_state: op_state.clone(),
dispatched_exception: None,
// Some fields are initialized later after isolate is created
inspector: None,
global_realm: None,
known_realms: Vec::with_capacity(1),
}));
let weak = Rc::downgrade(&state_rc);
let context_state = Rc::new(RefCell::new(ContextState::default()));
let op_ctxs = ops
.into_iter()
.enumerate()
.map(|(id, decl)| {
OpCtx::new(
id as u16,
context_state.clone(),
Rc::new(decl),
op_state.clone(),
weak.clone(),
)
})
.collect::<Vec<_>>()
.into_boxed_slice();
context_state.borrow_mut().op_ctxs = op_ctxs;
context_state.borrow_mut().isolate = Some(isolate_ptr);
let refs = bindings::external_references(&context_state.borrow().op_ctxs);
// V8 takes ownership of external_references.
let refs: &'static v8::ExternalReferences = Box::leak(Box::new(refs));
let mut isolate = if will_snapshot {
snapshot_util::create_snapshot_creator(
refs,
options.startup_snapshot.take(),
)
} else {
let mut params = options
.create_params
.take()
.unwrap_or_default()
.embedder_wrapper_type_info_offsets(
V8_WRAPPER_TYPE_INDEX,
V8_WRAPPER_OBJECT_INDEX,
)
.external_references(&**refs);
if let Some(snapshot) = options.startup_snapshot.take() {
params = match snapshot {
Snapshot::Static(data) => params.snapshot_blob(data),
Snapshot::JustCreated(data) => params.snapshot_blob(data),
Snapshot::Boxed(data) => params.snapshot_blob(data),
};
}
v8::Isolate::new(params)
};
isolate.set_capture_stack_trace_for_uncaught_exceptions(true, 10);
isolate.set_promise_reject_callback(bindings::promise_reject_callback);
isolate.set_host_initialize_import_meta_object_callback(
bindings::host_initialize_import_meta_object_callback,
);
isolate.set_host_import_module_dynamically_callback(
bindings::host_import_module_dynamically_callback,
);
isolate.set_wasm_async_resolve_promise_callback(
bindings::wasm_async_resolve_promise_callback,
);
let (global_context, snapshotted_data) = {
let scope = &mut v8::HandleScope::new(&mut isolate);
let context = v8::Context::new(scope);
// Get module map data from the snapshot
let snapshotted_data = if init_mode == InitMode::FromSnapshot {
Some(snapshot_util::get_snapshotted_data(scope, context))
} else {
None
};
(v8::Global::new(scope, context), snapshotted_data)
};
// SAFETY: this is first use of `isolate_ptr` so we are sure we're
// not overwriting an existing pointer.
isolate = unsafe {
isolate_ptr.write(isolate);
isolate_ptr.read()
};
let mut context_scope: v8::HandleScope =
v8::HandleScope::with_context(&mut isolate, global_context.clone());
let scope = &mut context_scope;
let context = v8::Local::new(scope, global_context.clone());
bindings::initialize_context(
scope,
context,
&context_state.borrow().op_ctxs,
init_mode,
);
context.set_slot(scope, context_state.clone());
op_state.borrow_mut().put(isolate_ptr);
let inspector = if options.inspector {
Some(JsRuntimeInspector::new(scope, context, options.is_main))
} else {
None
};
let loader = options
.module_loader
.unwrap_or_else(|| Rc::new(NoopModuleLoader));
{
let global_realm = JsRealmInner::new(
context_state,
global_context,
state_rc.clone(),
true,
);
let mut state = state_rc.borrow_mut();
state.global_realm = Some(JsRealm::new(global_realm.clone()));
state.inspector = inspector;
state.known_realms.push(global_realm);
}
scope.set_data(
STATE_DATA_OFFSET,
Rc::into_raw(state_rc.clone()) as *mut c_void,
);
let module_map_rc = Rc::new(RefCell::new(ModuleMap::new(loader)));
if let Some(snapshotted_data) = snapshotted_data {
let mut module_map = module_map_rc.borrow_mut();
module_map.update_with_snapshotted_data(scope, snapshotted_data);
}
scope.set_data(
MODULE_MAP_DATA_OFFSET,
Rc::into_raw(module_map_rc.clone()) as *mut c_void,
);
drop(context_scope);
let mut js_runtime = JsRuntime {
inner: InnerIsolateState {
will_snapshot,
state: ManuallyDropRc(ManuallyDrop::new(state_rc)),
v8_isolate: ManuallyDrop::new(isolate),
},
init_mode,
allocations: IsolateAllocations::default(),
event_loop_middlewares,
extensions: options.extensions,
module_map: module_map_rc,
is_main: options.is_main,
};
let realm = js_runtime.global_realm();
// TODO(mmastrac): We should thread errors back out of the runtime
js_runtime
.init_extension_js(&realm, maybe_load_callback)
.unwrap();
// If the user has requested that we rename modules
if let Some(rename_modules) = options.rename_modules {
js_runtime
.module_map
.borrow_mut()
.clear_module_map(rename_modules.into_iter());
}
js_runtime
}
#[cfg(test)]
#[inline]
pub(crate) fn module_map(&self) -> &Rc<RefCell<ModuleMap>> {
&self.module_map
}
#[inline]
pub fn global_context(&self) -> v8::Global<v8::Context> {
self
.inner
.state
.borrow()
.known_realms
.get(0)
.unwrap()
.context()
.clone()
}
#[inline]
pub fn v8_isolate(&mut self) -> &mut v8::OwnedIsolate {
&mut self.inner.v8_isolate
}
#[inline]
pub fn inspector(&mut self) -> Rc<RefCell<JsRuntimeInspector>> {
self.inner.state.borrow().inspector()
}
#[inline]
pub fn global_realm(&mut self) -> JsRealm {
let state = self.inner.state.borrow();
state.global_realm.clone().unwrap()
}
/// Returns the extensions that this runtime is using (including internal ones).
pub fn extensions(&self) -> &Vec<Extension> {
&self.extensions
}
/// Creates a new realm (V8 context) in this JS execution context,
/// pre-initialized with all of the extensions that were passed in
/// [`RuntimeOptions::extensions`] when the [`JsRuntime`] was
/// constructed.
pub fn create_realm(&mut self) -> Result<JsRealm, Error> {
let realm = {
let context_state = Rc::new(RefCell::new(ContextState::default()));
let op_ctxs: Box<[OpCtx]> = self
.global_realm()
.0
.state()
.borrow()
.op_ctxs
.iter()
.map(|op_ctx| {
OpCtx::new(
op_ctx.id,
context_state.clone(),
op_ctx.decl.clone(),
op_ctx.state.clone(),
op_ctx.runtime_state.clone(),
)
})
.collect();
context_state.borrow_mut().op_ctxs = op_ctxs;
context_state.borrow_mut().isolate = Some(self.v8_isolate() as _);
let raw_ptr = self.v8_isolate() as *mut v8::OwnedIsolate;
// SAFETY: Having the scope tied to self's lifetime makes it impossible to
// reference JsRuntimeState::op_ctxs while the scope is alive. Here we
// turn it into an unbound lifetime, which is sound because 1. it only
// lives until the end of this block, and 2. the HandleScope only has
// access to the isolate, and nothing else we're accessing from self does.
let isolate = unsafe { raw_ptr.as_mut() }.unwrap();
let scope = &mut v8::HandleScope::new(isolate);
let context = v8::Context::new(scope);
let scope = &mut v8::ContextScope::new(scope, context);
let context = bindings::initialize_context(
scope,
context,
&context_state.borrow().op_ctxs,
self.init_mode,
);
context.set_slot(scope, context_state.clone());
let realm = JsRealmInner::new(
context_state,
v8::Global::new(scope, context),
self.inner.state.clone(),
false,
);
let mut state = self.inner.state.borrow_mut();
state.known_realms.push(realm.clone());
JsRealm::new(realm)
};
self.init_extension_js(&realm, None)?;
Ok(realm)
}
#[inline]
pub fn handle_scope(&mut self) -> v8::HandleScope {
self.global_realm().handle_scope(self.v8_isolate())
}
/// Initializes JS of provided Extensions in the given realm.
fn init_extension_js(
&mut self,
realm: &JsRealm,
maybe_load_callback: Option<ExtModuleLoaderCb>,
) -> Result<(), Error> {
// Initialization of JS happens in phases:
// 1. Iterate through all extensions:
// a. Execute all extension "script" JS files
// b. Load all extension "module" JS files (but do not execute them yet)
// 2. Iterate through all extensions:
// a. If an extension has a `esm_entry_point`, execute it.
// Take extensions temporarily so we can avoid have a mutable reference to self
let extensions = std::mem::take(&mut self.extensions);
// TODO(nayeemrmn): Module maps should be per-realm.
let loader = self.module_map.borrow().loader.clone();
let ext_loader = Rc::new(ExtModuleLoader::new(
&extensions,
maybe_load_callback.map(Rc::new),
));
self.module_map.borrow_mut().loader = ext_loader;
let mut esm_entrypoints = vec![];
futures::executor::block_on(async {
for extension in &extensions {
let maybe_esm_entry_point = extension.get_esm_entry_point();
if let Some(esm_files) = extension.get_esm_sources() {
for file_source in esm_files {
self
.load_side_module(
&ModuleSpecifier::parse(file_source.specifier)?,
None,
)
.await?;
}
}
if let Some(entry_point) = maybe_esm_entry_point {
esm_entrypoints.push(entry_point);
}
if let Some(js_files) = extension.get_js_sources() {
for file_source in js_files {
realm.execute_script(
self.v8_isolate(),
file_source.specifier,
file_source.load()?,
)?;
}
}
if extension.is_core {
self.init_cbs(realm);
}
}
for specifier in esm_entrypoints {
let mod_id = {
self
.module_map
.borrow()
.get_id(specifier, AssertedModuleType::JavaScriptOrWasm)
.unwrap_or_else(|| {
panic!("{} not present in the module map", specifier)
})
};
let receiver = self.mod_evaluate(mod_id);
self.run_event_loop(false).await?;
receiver
.await?
.with_context(|| format!("Couldn't execute '{specifier}'"))?;
}
#[cfg(debug_assertions)]
{
let module_map_rc = self.module_map.clone();
let mut scope = realm.handle_scope(self.v8_isolate());
let module_map = module_map_rc.borrow();
module_map.assert_all_modules_evaluated(&mut scope);
}
Ok::<_, anyhow::Error>(())
})?;
self.extensions = extensions;
self.module_map.borrow_mut().loader = loader;
Ok(())
}
/// Collects ops from extensions & applies middleware
fn collect_ops(exts: &mut [Extension]) -> Vec<OpDecl> {
for (ext, previous_exts) in
exts.iter().enumerate().map(|(i, ext)| (ext, &exts[..i]))
{
ext.check_dependencies(previous_exts);
}
// Middleware
let middleware: Vec<Box<OpMiddlewareFn>> = exts
.iter_mut()
.filter_map(|e| e.init_middleware())
.collect();
// macroware wraps an opfn in all the middleware
let macroware = move |d| middleware.iter().fold(d, |d, m| m(d));
// Flatten ops, apply middlware & override disabled ops
let ops: Vec<_> = exts
.iter_mut()
.filter_map(|e| e.init_ops())
.flatten()
.map(|d| OpDecl {
name: d.name,
..macroware(d)
})
.collect();
// In debug build verify there are no duplicate ops.
#[cfg(debug_assertions)]
{
let mut count_by_name = HashMap::new();
for op in ops.iter() {
count_by_name
.entry(&op.name)
.or_insert(vec![])
.push(op.name.to_string());
}
let mut duplicate_ops = vec![];
for (op_name, _count) in
count_by_name.iter().filter(|(_k, v)| v.len() > 1)
{
duplicate_ops.push(op_name.to_string());
}
if !duplicate_ops.is_empty() {
let mut msg = "Found ops with duplicate names:\n".to_string();
for op_name in duplicate_ops {
msg.push_str(&format!(" - {}\n", op_name));
}
msg.push_str("Op names need to be unique.");
panic!("{}", msg);
}
}
ops
}
/// Initializes ops of provided Extensions
fn create_opstate(
options: &mut RuntimeOptions,
init_mode: InitMode,
) -> (OpState, Vec<OpDecl>) {
// Add built-in extension
if init_mode == InitMode::FromSnapshot {
options
.extensions
.insert(0, crate::ops_builtin::core::init_ops());
} else {
options
.extensions
.insert(0, crate::ops_builtin::core::init_ops_and_esm());
}
let ops = Self::collect_ops(&mut options.extensions);
let mut op_state = OpState::new(ops.len());
if let Some(get_error_class_fn) = options.get_error_class_fn {
op_state.get_error_class_fn = get_error_class_fn;
}
// Setup state
for e in &mut options.extensions {
// ops are already registered during in bindings::initialize_context();
e.init_state(&mut op_state);
}
(op_state, ops)
}
pub fn eval<'s, T>(
scope: &mut v8::HandleScope<'s>,
code: &str,
) -> Option<v8::Local<'s, T>>
where
v8::Local<'s, T>: TryFrom<v8::Local<'s, v8::Value>, Error = v8::DataError>,
{
let scope = &mut v8::EscapableHandleScope::new(scope);
let source = v8::String::new(scope, code).unwrap();
let script = v8::Script::compile(scope, source, None).unwrap();
let v = script.run(scope)?;
scope.escape(v).try_into().ok()
}
/// Grabs a reference to core.js' eventLoopTick & buildCustomError
fn init_cbs(&mut self, realm: &JsRealm) {
let (event_loop_tick_cb, build_custom_error_cb) = {
let scope = &mut realm.handle_scope(self.v8_isolate());
let context = realm.context();
let context_local = v8::Local::new(scope, context);
let global = context_local.global(scope);
let deno_str =
v8::String::new_external_onebyte_static(scope, b"Deno").unwrap();
let core_str =
v8::String::new_external_onebyte_static(scope, b"core").unwrap();
let event_loop_tick_str =
v8::String::new_external_onebyte_static(scope, b"eventLoopTick")
.unwrap();
let build_custom_error_str =
v8::String::new_external_onebyte_static(scope, b"buildCustomError")
.unwrap();
let deno_obj: v8::Local<v8::Object> = global
.get(scope, deno_str.into())
.unwrap()
.try_into()
.unwrap();
let core_obj: v8::Local<v8::Object> = deno_obj
.get(scope, core_str.into())
.unwrap()
.try_into()
.unwrap();
let event_loop_tick_cb: v8::Local<v8::Function> = core_obj
.get(scope, event_loop_tick_str.into())
.unwrap()
.try_into()
.unwrap();
let build_custom_error_cb: v8::Local<v8::Function> = core_obj
.get(scope, build_custom_error_str.into())
.unwrap()
.try_into()
.unwrap();
(
v8::Global::new(scope, event_loop_tick_cb),
v8::Global::new(scope, build_custom_error_cb),
)
};
// Put global handles in the realm's ContextState
let state_rc = realm.0.state();
let mut state = state_rc.borrow_mut();
state
.js_event_loop_tick_cb
.replace(Rc::new(event_loop_tick_cb));
state
.js_build_custom_error_cb
.replace(Rc::new(build_custom_error_cb));
}
/// Returns the runtime's op state, which can be used to maintain ops
/// and access resources between op calls.
pub fn op_state(&mut self) -> Rc<RefCell<OpState>> {
let state = self.inner.state.borrow();
state.op_state.clone()
}
/// Executes traditional JavaScript code (traditional = not ES modules).
///
/// The execution takes place on the current global context, so it is possible
/// to maintain local JS state and invoke this method multiple times.
///
/// `name` can be a filepath or any other string, but it is required to be 7-bit ASCII, eg.
///
/// - "/some/file/path.js"
/// - "<anon>"
/// - "[native code]"
///
/// The same `name` value can be used for multiple executions.
///
/// `Error` can usually be downcast to `JsError`.
pub fn execute_script(
&mut self,
name: &'static str,
source_code: ModuleCode,
) -> Result<v8::Global<v8::Value>, Error> {
self
.global_realm()
.execute_script(self.v8_isolate(), name, source_code)
}
/// Executes traditional JavaScript code (traditional = not ES modules).
///
/// The execution takes place on the current global context, so it is possible
/// to maintain local JS state and invoke this method multiple times.
///
/// `name` can be a filepath or any other string, but it is required to be 7-bit ASCII, eg.
///
/// - "/some/file/path.js"
/// - "<anon>"
/// - "[native code]"
///
/// The same `name` value can be used for multiple executions.
///
/// `Error` can usually be downcast to `JsError`.
pub fn execute_script_static(
&mut self,
name: &'static str,
source_code: &'static str,
) -> Result<v8::Global<v8::Value>, Error> {
self.global_realm().execute_script(
self.v8_isolate(),
name,
ModuleCode::from_static(source_code),
)
}
/// Call a function. If it returns a promise, run the event loop until that
/// promise is settled. If the promise rejects or there is an uncaught error
/// in the event loop, return `Err(error)`. Or return `Ok(<await returned>)`.
pub async fn call_and_await(
&mut self,
function: &v8::Global<v8::Function>,
) -> Result<v8::Global<v8::Value>, Error> {
let promise = {
let scope = &mut self.handle_scope();
let cb = function.open(scope);
let this = v8::undefined(scope).into();
let promise = cb.call(scope, this, &[]);
if promise.is_none() || scope.is_execution_terminating() {
let undefined = v8::undefined(scope).into();
return exception_to_err_result(scope, undefined, false);
}
v8::Global::new(scope, promise.unwrap())
};
self.resolve_value(promise).await
}
/// Returns the namespace object of a module.
///
/// This is only available after module evaluation has completed.
/// This function panics if module has not been instantiated.
pub fn get_module_namespace(
&mut self,
module_id: ModuleId,
) -> Result<v8::Global<v8::Object>, Error> {
self
.module_map
.clone()
.borrow()
.get_module_namespace(&mut self.handle_scope(), module_id)
}
/// Registers a callback on the isolate when the memory limits are approached.
/// Use this to prevent V8 from crashing the process when reaching the limit.
///
/// Calls the closure with the current heap limit and the initial heap limit.
/// The return value of the closure is set as the new limit.
pub fn add_near_heap_limit_callback<C>(&mut self, cb: C)
where
C: FnMut(usize, usize) -> usize + 'static,
{
let boxed_cb = Box::new(RefCell::new(cb));
let data = boxed_cb.as_ptr() as *mut c_void;
let prev = self
.allocations
.near_heap_limit_callback_data
.replace((boxed_cb, near_heap_limit_callback::<C>));
if let Some((_, prev_cb)) = prev {
self
.v8_isolate()
.remove_near_heap_limit_callback(prev_cb, 0);
}
self
.v8_isolate()
.add_near_heap_limit_callback(near_heap_limit_callback::<C>, data);
}
pub fn remove_near_heap_limit_callback(&mut self, heap_limit: usize) {
if let Some((_, cb)) = self.allocations.near_heap_limit_callback_data.take()
{
self
.v8_isolate()
.remove_near_heap_limit_callback(cb, heap_limit);
}
}
fn pump_v8_message_loop(&mut self) -> Result<(), Error> {
let scope = &mut self.handle_scope();
while v8::Platform::pump_message_loop(
&v8::V8::get_current_platform(),
scope,
false, // don't block if there are no tasks
) {
// do nothing
}
let tc_scope = &mut v8::TryCatch::new(scope);
tc_scope.perform_microtask_checkpoint();
match tc_scope.exception() {
None => Ok(()),
Some(exception) => exception_to_err_result(tc_scope, exception, false),
}
}
pub fn maybe_init_inspector(&mut self) {
if self.inner.state.borrow().inspector.is_some() {
return;
}
let context = self.global_context();
let scope = &mut v8::HandleScope::with_context(
self.inner.v8_isolate.as_mut(),
context.clone(),
);
let context = v8::Local::new(scope, context);
let mut state = self.inner.state.borrow_mut();
state.inspector =
Some(JsRuntimeInspector::new(scope, context, self.is_main));
}
pub fn poll_value(
&mut self,
global: &v8::Global<v8::Value>,
cx: &mut Context,
) -> Poll<Result<v8::Global<v8::Value>, Error>> {
let state = self.poll_event_loop(cx, false);
let mut scope = self.handle_scope();
let local = v8::Local::<v8::Value>::new(&mut scope, global);
if let Ok(promise) = v8::Local::<v8::Promise>::try_from(local) {
match promise.state() {
v8::PromiseState::Pending => match state {
Poll::Ready(Ok(_)) => {
let msg = "Promise resolution is still pending but the event loop has already resolved.";
Poll::Ready(Err(generic_error(msg)))
}
Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
Poll::Pending => Poll::Pending,
},
v8::PromiseState::Fulfilled => {
let value = promise.result(&mut scope);
let value_handle = v8::Global::new(&mut scope, value);
Poll::Ready(Ok(value_handle))
}
v8::PromiseState::Rejected => {
let exception = promise.result(&mut scope);
Poll::Ready(exception_to_err_result(&mut scope, exception, false))
}
}
} else {
let value_handle = v8::Global::new(&mut scope, local);
Poll::Ready(Ok(value_handle))
}
}
/// Waits for the given value to resolve while polling the event loop.
///
/// This future resolves when either the value is resolved or the event loop runs to
/// completion.
pub async fn resolve_value(
&mut self,
global: v8::Global<v8::Value>,
) -> Result<v8::Global<v8::Value>, Error> {
poll_fn(|cx| self.poll_value(&global, cx)).await
}
/// Runs event loop to completion
///
/// This future resolves when:
/// - there are no more pending dynamic imports
/// - there are no more pending ops
/// - there are no more active inspector sessions (only if `wait_for_inspector` is set to true)
pub async fn run_event_loop(
&mut self,
wait_for_inspector: bool,
) -> Result<(), Error> {
poll_fn(|cx| self.poll_event_loop(cx, wait_for_inspector)).await
}
/// Runs a single tick of event loop
///
/// If `wait_for_inspector` is set to true event loop
/// will return `Poll::Pending` if there are active inspector sessions.
pub fn poll_event_loop(
&mut self,
cx: &mut Context,
wait_for_inspector: bool,
) -> Poll<Result<(), Error>> {
let has_inspector: bool;
{
let state = self.inner.state.borrow();
has_inspector = state.inspector.is_some();
state.op_state.borrow().waker.register(cx.waker());
}
if has_inspector {
// We poll the inspector first.
let _ = self.inspector().borrow().poll_sessions(Some(cx)).unwrap();
}
let module_map = self.module_map.clone();
self.pump_v8_message_loop()?;
// Dynamic module loading - ie. modules loaded using "import()"
{
// Run in a loop so that dynamic imports that only depend on another
// dynamic import can be resolved in this event loop iteration.
//
// For example, a dynamically imported module like the following can be
// immediately resolved after `dependency.ts` is fully evaluated, but it
// wouldn't if not for this loop.
//
// await delay(1000);
// await import("./dependency.ts");
// console.log("test")
//
loop {
let poll_imports = self.prepare_dyn_imports(cx)?;
assert!(poll_imports.is_ready());
let poll_imports = self.poll_dyn_imports(cx)?;
assert!(poll_imports.is_ready());
if !self.evaluate_dyn_imports() {
break;
}
}
}
// Resolve async ops, run all next tick callbacks and macrotasks callbacks
// and only then check for any promise exceptions (`unhandledrejection`
// handlers are run in macrotasks callbacks so we need to let them run
// first).
self.do_js_event_loop_tick(cx)?;
self.check_promise_rejections()?;
// Event loop middlewares
let mut maybe_scheduling = false;
{
let op_state = self.inner.state.borrow().op_state.clone();
for f in &self.event_loop_middlewares {
if f(op_state.clone(), cx) {
maybe_scheduling = true;
}
}
}
// Top level module
self.evaluate_pending_module();
let pending_state = self.event_loop_pending_state();
if !pending_state.is_pending() && !maybe_scheduling {
if has_inspector {
let inspector = self.inspector();
let has_active_sessions = inspector.borrow().has_active_sessions();
let has_blocking_sessions = inspector.borrow().has_blocking_sessions();
if wait_for_inspector && has_active_sessions {
// If there are no blocking sessions (eg. REPL) we can now notify
// debugger that the program has finished running and we're ready
// to exit the process once debugger disconnects.
if !has_blocking_sessions {
let context = self.global_context();
let scope = &mut self.handle_scope();
inspector.borrow_mut().context_destroyed(scope, context);
println!("Program finished. Waiting for inspector to disconnect to exit the process...");
}
return Poll::Pending;
}
}
return Poll::Ready(Ok(()));
}
let state = self.inner.state.borrow();
// Check if more async ops have been dispatched
// during this turn of event loop.
// If there are any pending background tasks, we also wake the runtime to
// make sure we don't miss them.
// TODO(andreubotella) The event loop will spin as long as there are pending
// background tasks. We should look into having V8 notify us when a
// background task is done.
if pending_state.has_pending_background_tasks
|| pending_state.has_tick_scheduled
|| maybe_scheduling
{
state.op_state.borrow().waker.wake();
}
drop(state);
if pending_state.has_pending_module_evaluation {
if pending_state.has_pending_refed_ops
|| pending_state.has_pending_dyn_imports
|| pending_state.has_pending_dyn_module_evaluation
|| pending_state.has_pending_background_tasks
|| pending_state.has_tick_scheduled
|| maybe_scheduling
{
// pass, will be polled again
} else {
let scope = &mut self.handle_scope();
let messages = module_map.borrow().find_stalled_top_level_await(scope);
// We are gonna print only a single message to provide a nice formatting
// with source line of offending promise shown. Once user fixed it, then
// they will get another error message for the next promise (but this
// situation is gonna be very rare, if ever happening).
assert!(!messages.is_empty());
let msg = v8::Local::new(scope, messages[0].clone());
let js_error = JsError::from_v8_message(scope, msg);
return Poll::Ready(Err(js_error.into()));
}
}
if pending_state.has_pending_dyn_module_evaluation {
if pending_state.has_pending_refed_ops
|| pending_state.has_pending_dyn_imports
|| pending_state.has_pending_background_tasks
|| pending_state.has_tick_scheduled
{
// pass, will be polled again
} else if self.inner.state.borrow().dyn_module_evaluate_idle_counter >= 1
{
let scope = &mut self.handle_scope();
let messages = module_map.borrow().find_stalled_top_level_await(scope);
// We are gonna print only a single message to provide a nice formatting
// with source line of offending promise shown. Once user fixed it, then
// they will get another error message for the next promise (but this
// situation is gonna be very rare, if ever happening).
assert!(!messages.is_empty());
let msg = v8::Local::new(scope, messages[0].clone());
let js_error = JsError::from_v8_message(scope, msg);
return Poll::Ready(Err(js_error.into()));
} else {
let mut state = self.inner.state.borrow_mut();
// Delay the above error by one spin of the event loop. A dynamic import
// evaluation may complete during this, in which case the counter will
// reset.
state.dyn_module_evaluate_idle_counter += 1;
state.op_state.borrow().waker.wake();
}
}
Poll::Pending
}
fn event_loop_pending_state(&mut self) -> EventLoopPendingState {
let mut scope = v8::HandleScope::new(self.inner.v8_isolate.as_mut());
EventLoopPendingState::new(
&mut scope,
&mut self.inner.state.borrow_mut(),
&self.module_map.borrow(),
)
}
}
impl JsRuntimeForSnapshot {
pub fn new(
mut options: RuntimeOptions,
runtime_snapshot_options: RuntimeSnapshotOptions,
) -> JsRuntimeForSnapshot {
JsRuntime::init_v8(options.v8_platform.take(), true);
JsRuntimeForSnapshot(JsRuntime::new_inner(
options,
true,
runtime_snapshot_options.snapshot_module_load_cb,
))
}
/// Takes a snapshot and consumes the runtime.
///
/// `Error` can usually be downcast to `JsError`.
pub fn snapshot(mut self) -> v8::StartupData {
// Ensure there are no live inspectors to prevent crashes.
self.inner.prepare_for_cleanup();
// Set the context to be snapshot's default context
{
let context = self.global_context();
let mut scope = self.handle_scope();
let local_context = v8::Local::new(&mut scope, context);
scope.set_default_context(local_context);
}
// Serialize the module map and store its data in the snapshot.
{
let snapshotted_data = {
// `self.module_map` points directly to the v8 isolate data slot, which
// we must explicitly drop before destroying the isolate. We have to
// take and drop this `Rc` before that.
let module_map_rc = std::mem::take(&mut self.module_map);
let module_map = module_map_rc.borrow();
module_map.serialize_for_snapshotting(&mut self.handle_scope())
};
let context = self.global_context();
let mut scope = self.handle_scope();
snapshot_util::set_snapshotted_data(
&mut scope,
context,
snapshotted_data,
);
}
self
.0
.inner
.prepare_for_snapshot()
.create_blob(v8::FunctionCodeHandling::Keep)
.unwrap()
}
}
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub(crate) struct EventLoopPendingState {
has_pending_refed_ops: bool,
has_pending_dyn_imports: bool,
has_pending_dyn_module_evaluation: bool,
has_pending_module_evaluation: bool,
has_pending_background_tasks: bool,
has_tick_scheduled: bool,
}
impl EventLoopPendingState {
pub fn new(
scope: &mut v8::HandleScope<()>,
state: &mut JsRuntimeState,
module_map: &ModuleMap,
) -> EventLoopPendingState {
let mut num_unrefed_ops = 0;
let mut num_pending_ops = 0;
for realm in &state.known_realms {
num_unrefed_ops += realm.num_unrefed_ops();
num_pending_ops += realm.num_pending_ops();
}
EventLoopPendingState {
has_pending_refed_ops: num_pending_ops > num_unrefed_ops,
has_pending_dyn_imports: module_map.has_pending_dynamic_imports(),
has_pending_dyn_module_evaluation: !state
.pending_dyn_mod_evaluate
.is_empty(),
has_pending_module_evaluation: state.pending_mod_evaluate.is_some(),
has_pending_background_tasks: scope.has_pending_background_tasks(),
has_tick_scheduled: state.has_tick_scheduled,
}
}
pub fn is_pending(&self) -> bool {
self.has_pending_refed_ops
|| self.has_pending_dyn_imports
|| self.has_pending_dyn_module_evaluation
|| self.has_pending_module_evaluation
|| self.has_pending_background_tasks
|| self.has_tick_scheduled
}
}
extern "C" fn near_heap_limit_callback<F>(
data: *mut c_void,
current_heap_limit: usize,
initial_heap_limit: usize,
) -> usize
where
F: FnMut(usize, usize) -> usize,
{
// SAFETY: The data is a pointer to the Rust callback function. It is stored
// in `JsRuntime::allocations` and thus is guaranteed to outlive the isolate.
let callback = unsafe { &mut *(data as *mut F) };
callback(current_heap_limit, initial_heap_limit)
}
impl JsRuntimeState {
pub(crate) fn inspector(&self) -> Rc<RefCell<JsRuntimeInspector>> {
self.inspector.as_ref().unwrap().clone()
}
/// Called by `bindings::host_import_module_dynamically_callback`
/// after initiating new dynamic import load.
pub fn notify_new_dynamic_import(&mut self) {
// Notify event loop to poll again soon.
self.op_state.borrow().waker.wake();
}
}
// Related to module loading
impl JsRuntime {
pub(crate) fn instantiate_module(
&mut self,
id: ModuleId,
) -> Result<(), v8::Global<v8::Value>> {
self
.module_map
.clone()
.borrow_mut()
.instantiate_module(&mut self.handle_scope(), id)
}
fn dynamic_import_module_evaluate(
&mut self,
load_id: ModuleLoadId,
id: ModuleId,
) -> Result<(), Error> {
let module_handle = self
.module_map
.borrow()
.get_handle(id)
.expect("ModuleInfo not found");
let status = {
let scope = &mut self.handle_scope();
let module = module_handle.open(scope);
module.get_status()
};
match status {
v8::ModuleStatus::Instantiated | v8::ModuleStatus::Evaluated => {}
_ => return Ok(()),
}
// IMPORTANT: Top-level-await is enabled, which means that return value
// of module evaluation is a promise.
//
// This promise is internal, and not the same one that gets returned to
// the user. We add an empty `.catch()` handler so that it does not result
// in an exception if it rejects. That will instead happen for the other
// promise if not handled by the user.
//
// For more details see:
// https://github.com/denoland/deno/issues/4908
// https://v8.dev/features/top-level-await#module-execution-order
let global_realm =
self.inner.state.borrow_mut().global_realm.clone().unwrap();
let scope = &mut global_realm.handle_scope(&mut self.inner.v8_isolate);
let tc_scope = &mut v8::TryCatch::new(scope);
let module = v8::Local::new(tc_scope, &module_handle);
let maybe_value = module.evaluate(tc_scope);
// Update status after evaluating.
let status = module.get_status();
if let Some(value) = maybe_value {
assert!(
status == v8::ModuleStatus::Evaluated
|| status == v8::ModuleStatus::Errored
);
let promise = v8::Local::<v8::Promise>::try_from(value)
.expect("Expected to get promise as module evaluation result");
let empty_fn = bindings::create_empty_fn(tc_scope).unwrap();
promise.catch(tc_scope, empty_fn);
let promise_global = v8::Global::new(tc_scope, promise);
let module_global = v8::Global::new(tc_scope, module);
let dyn_import_mod_evaluate = DynImportModEvaluate {
load_id,
module_id: id,
promise: promise_global,
module: module_global,
};
self
.inner
.state
.borrow_mut()
.pending_dyn_mod_evaluate
.push(dyn_import_mod_evaluate);
} else if tc_scope.has_terminated() || tc_scope.is_execution_terminating() {
return Err(
generic_error("Cannot evaluate dynamically imported module, because JavaScript execution has been terminated.")
);
} else {
assert!(status == v8::ModuleStatus::Errored);
}
Ok(())
}
// TODO(bartlomieju): make it return `ModuleEvaluationFuture`?
/// Evaluates an already instantiated ES module.
///
/// Returns a receiver handle that resolves when module promise resolves.
/// Implementors must manually call [`JsRuntime::run_event_loop`] to drive
/// module evaluation future.
///
/// `Error` can usually be downcast to `JsError` and should be awaited and
/// checked after [`JsRuntime::run_event_loop`] completion.
///
/// This function panics if module has not been instantiated.
pub fn mod_evaluate(
&mut self,
id: ModuleId,
) -> oneshot::Receiver<Result<(), Error>> {
let global_realm = self.global_realm();
let state_rc = self.inner.state.clone();
let module_map_rc = self.module_map.clone();
let scope = &mut self.handle_scope();
let tc_scope = &mut v8::TryCatch::new(scope);
let module = module_map_rc
.borrow()
.get_handle(id)
.map(|handle| v8::Local::new(tc_scope, handle))
.expect("ModuleInfo not found");
let mut status = module.get_status();
assert_eq!(
status,
v8::ModuleStatus::Instantiated,
"Module not instantiated {id}"
);
let (sender, receiver) = oneshot::channel();
// IMPORTANT: Top-level-await is enabled, which means that return value
// of module evaluation is a promise.
//
// Because that promise is created internally by V8, when error occurs during
// module evaluation the promise is rejected, and since the promise has no rejection
// handler it will result in call to `bindings::promise_reject_callback` adding
// the promise to pending promise rejection table - meaning JsRuntime will return
// error on next poll().
//
// This situation is not desirable as we want to manually return error at the
// end of this function to handle it further. It means we need to manually
// remove this promise from pending promise rejection table.
//
// For more details see:
// https://github.com/denoland/deno/issues/4908
// https://v8.dev/features/top-level-await#module-execution-order
{
let mut state = state_rc.borrow_mut();
assert!(
state.pending_mod_evaluate.is_none(),
"There is already pending top level module evaluation"
);
state.pending_mod_evaluate = Some(ModEvaluate {
promise: None,
has_evaluated: false,
handled_promise_rejections: vec![],
sender,
});
}
let maybe_value = module.evaluate(tc_scope);
{
let mut state = state_rc.borrow_mut();
let pending_mod_evaluate = state.pending_mod_evaluate.as_mut().unwrap();
pending_mod_evaluate.has_evaluated = true;
}
// Update status after evaluating.
status = module.get_status();
let has_dispatched_exception =
state_rc.borrow_mut().dispatched_exception.is_some();
if has_dispatched_exception {
// This will be overrided in `exception_to_err_result()`.
let exception = v8::undefined(tc_scope).into();
let pending_mod_evaluate = {
let mut state = state_rc.borrow_mut();
state.pending_mod_evaluate.take().unwrap()
};
pending_mod_evaluate
.sender
.send(exception_to_err_result(tc_scope, exception, false))
.expect("Failed to send module evaluation error.");
} else if let Some(value) = maybe_value {
assert!(
status == v8::ModuleStatus::Evaluated
|| status == v8::ModuleStatus::Errored
);
let promise = v8::Local::<v8::Promise>::try_from(value)
.expect("Expected to get promise as module evaluation result");
let promise_global = v8::Global::new(tc_scope, promise);
let mut state = state_rc.borrow_mut();
{
let pending_mod_evaluate = state.pending_mod_evaluate.as_ref().unwrap();
let pending_rejection_was_already_handled = pending_mod_evaluate
.handled_promise_rejections
.contains(&promise_global);
if !pending_rejection_was_already_handled {
global_realm
.0
.state()
.borrow_mut()
.pending_promise_rejections
.retain(|(key, _)| key != &promise_global);
}
}
let promise_global = v8::Global::new(tc_scope, promise);
state.pending_mod_evaluate.as_mut().unwrap().promise =
Some(promise_global);
tc_scope.perform_microtask_checkpoint();
} else if tc_scope.has_terminated() || tc_scope.is_execution_terminating() {
let pending_mod_evaluate = {
let mut state = state_rc.borrow_mut();
state.pending_mod_evaluate.take().unwrap()
};
pending_mod_evaluate.sender.send(Err(
generic_error("Cannot evaluate module, because JavaScript execution has been terminated.")
)).expect("Failed to send module evaluation error.");
} else {
assert!(status == v8::ModuleStatus::Errored);
}
receiver
}
fn dynamic_import_reject(
&mut self,
id: ModuleLoadId,
exception: v8::Global<v8::Value>,
) {
let module_map_rc = self.module_map.clone();
let scope = &mut self.handle_scope();
let resolver_handle = module_map_rc
.borrow_mut()
.dynamic_import_map
.remove(&id)
.expect("Invalid dynamic import id");
let resolver = resolver_handle.open(scope);
// IMPORTANT: No borrows to `ModuleMap` can be held at this point because
// rejecting the promise might initiate another `import()` which will
// in turn call `bindings::host_import_module_dynamically_callback` which
// will reach into `ModuleMap` from within the isolate.
let exception = v8::Local::new(scope, exception);
resolver.reject(scope, exception).unwrap();
scope.perform_microtask_checkpoint();
}
fn dynamic_import_resolve(&mut self, id: ModuleLoadId, mod_id: ModuleId) {
let state_rc = self.inner.state.clone();
let module_map_rc = self.module_map.clone();
let scope = &mut self.handle_scope();
let resolver_handle = module_map_rc
.borrow_mut()
.dynamic_import_map
.remove(&id)
.expect("Invalid dynamic import id");
let resolver = resolver_handle.open(scope);
let module = {
module_map_rc
.borrow()
.get_handle(mod_id)
.map(|handle| v8::Local::new(scope, handle))
.expect("Dyn import module info not found")
};
// Resolution success
assert_eq!(module.get_status(), v8::ModuleStatus::Evaluated);
// IMPORTANT: No borrows to `ModuleMap` can be held at this point because
// resolving the promise might initiate another `import()` which will
// in turn call `bindings::host_import_module_dynamically_callback` which
// will reach into `ModuleMap` from within the isolate.
let module_namespace = module.get_module_namespace();
resolver.resolve(scope, module_namespace).unwrap();
state_rc.borrow_mut().dyn_module_evaluate_idle_counter = 0;
scope.perform_microtask_checkpoint();
}
fn prepare_dyn_imports(
&mut self,
cx: &mut Context,
) -> Poll<Result<(), Error>> {
if self
.module_map
.borrow()
.preparing_dynamic_imports
.is_empty()
{
return Poll::Ready(Ok(()));
}
loop {
let poll_result = self
.module_map
.borrow_mut()
.preparing_dynamic_imports
.poll_next_unpin(cx);
if let Poll::Ready(Some(prepare_poll)) = poll_result {
let dyn_import_id = prepare_poll.0;
let prepare_result = prepare_poll.1;
match prepare_result {
Ok(load) => {
self
.module_map
.borrow_mut()
.pending_dynamic_imports
.push(load.into_future());
}
Err(err) => {
let exception = to_v8_type_error(&mut self.handle_scope(), err);
self.dynamic_import_reject(dyn_import_id, exception);
}
}
// Continue polling for more prepared dynamic imports.
continue;
}
// There are no active dynamic import loads, or none are ready.
return Poll::Ready(Ok(()));
}
}
fn poll_dyn_imports(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> {
if self.module_map.borrow().pending_dynamic_imports.is_empty() {
return Poll::Ready(Ok(()));
}
loop {
let poll_result = self
.module_map
.borrow_mut()
.pending_dynamic_imports
.poll_next_unpin(cx);
if let Poll::Ready(Some(load_stream_poll)) = poll_result {
let maybe_result = load_stream_poll.0;
let mut load = load_stream_poll.1;
let dyn_import_id = load.id;
if let Some(load_stream_result) = maybe_result {
match load_stream_result {
Ok((request, info)) => {
// A module (not necessarily the one dynamically imported) has been
// fetched. Create and register it, and if successful, poll for the
// next recursive-load event related to this dynamic import.
let register_result = load.register_and_recurse(
&mut self.handle_scope(),
&request,
info,
);
match register_result {
Ok(()) => {
// Keep importing until it's fully drained
self
.module_map
.borrow_mut()
.pending_dynamic_imports
.push(load.into_future());
}
Err(err) => {
let exception = match err {
ModuleError::Exception(e) => e,
ModuleError::Other(e) => {
to_v8_type_error(&mut self.handle_scope(), e)
}
};
self.dynamic_import_reject(dyn_import_id, exception)
}
}
}
Err(err) => {
// A non-javascript error occurred; this could be due to a an invalid
// module specifier, or a problem with the source map, or a failure
// to fetch the module source code.
let exception = to_v8_type_error(&mut self.handle_scope(), err);
self.dynamic_import_reject(dyn_import_id, exception);
}
}
} else {
// The top-level module from a dynamic import has been instantiated.
// Load is done.
let module_id =
load.root_module_id.expect("Root module should be loaded");
let result = self.instantiate_module(module_id);
if let Err(exception) = result {
self.dynamic_import_reject(dyn_import_id, exception);
}
self.dynamic_import_module_evaluate(dyn_import_id, module_id)?;
}
// Continue polling for more ready dynamic imports.
continue;
}
// There are no active dynamic import loads, or none are ready.
return Poll::Ready(Ok(()));
}
}
/// "deno_core" runs V8 with Top Level Await enabled. It means that each
/// module evaluation returns a promise from V8.
/// Feature docs: https://v8.dev/features/top-level-await
///
/// This promise resolves after all dependent modules have also
/// resolved. Each dependent module may perform calls to "import()" and APIs
/// using async ops will add futures to the runtime's event loop.
/// It means that the promise returned from module evaluation will
/// resolve only after all futures in the event loop are done.
///
/// Thus during turn of event loop we need to check if V8 has
/// resolved or rejected the promise. If the promise is still pending
/// then another turn of event loop must be performed.
fn evaluate_pending_module(&mut self) {
let maybe_module_evaluation =
self.inner.state.borrow_mut().pending_mod_evaluate.take();
if maybe_module_evaluation.is_none() {
return;
}
let mut module_evaluation = maybe_module_evaluation.unwrap();
let state_rc = self.inner.state.clone();
let scope = &mut self.handle_scope();
let promise_global = module_evaluation.promise.clone().unwrap();
let promise = promise_global.open(scope);
let promise_state = promise.state();
match promise_state {
v8::PromiseState::Pending => {
// NOTE: `poll_event_loop` will decide if
// runtime would be woken soon
state_rc.borrow_mut().pending_mod_evaluate = Some(module_evaluation);
}
v8::PromiseState::Fulfilled => {
scope.perform_microtask_checkpoint();
// Receiver end might have been already dropped, ignore the result
let _ = module_evaluation.sender.send(Ok(()));
module_evaluation.handled_promise_rejections.clear();
}
v8::PromiseState::Rejected => {
let exception = promise.result(scope);
scope.perform_microtask_checkpoint();
// Receiver end might have been already dropped, ignore the result
if module_evaluation
.handled_promise_rejections
.contains(&promise_global)
{
let _ = module_evaluation.sender.send(Ok(()));
module_evaluation.handled_promise_rejections.clear();
} else {
let _ = module_evaluation
.sender
.send(exception_to_err_result(scope, exception, false));
}
}
}
}
// Returns true if some dynamic import was resolved.
fn evaluate_dyn_imports(&mut self) -> bool {
let pending = std::mem::take(
&mut self.inner.state.borrow_mut().pending_dyn_mod_evaluate,
);
if pending.is_empty() {
return false;
}
let mut resolved_any = false;
let mut still_pending = vec![];
for pending_dyn_evaluate in pending {
let maybe_result = {
let scope = &mut self.handle_scope();
let module_id = pending_dyn_evaluate.module_id;
let promise = pending_dyn_evaluate.promise.open(scope);
let _module = pending_dyn_evaluate.module.open(scope);
let promise_state = promise.state();
match promise_state {
v8::PromiseState::Pending => {
still_pending.push(pending_dyn_evaluate);
None
}
v8::PromiseState::Fulfilled => {
Some(Ok((pending_dyn_evaluate.load_id, module_id)))
}
v8::PromiseState::Rejected => {
let exception = promise.result(scope);
let exception = v8::Global::new(scope, exception);
Some(Err((pending_dyn_evaluate.load_id, exception)))
}
}
};
if let Some(result) = maybe_result {
resolved_any = true;
match result {
Ok((dyn_import_id, module_id)) => {
self.dynamic_import_resolve(dyn_import_id, module_id);
}
Err((dyn_import_id, exception)) => {
self.dynamic_import_reject(dyn_import_id, exception);
}
}
}
}
self.inner.state.borrow_mut().pending_dyn_mod_evaluate = still_pending;
resolved_any
}
/// Asynchronously load specified module and all of its dependencies.
///
/// The module will be marked as "main", and because of that
/// "import.meta.main" will return true when checked inside that module.
///
/// User must call [`JsRuntime::mod_evaluate`] with returned `ModuleId`
/// manually after load is finished.
pub async fn load_main_module(
&mut self,
specifier: &ModuleSpecifier,
code: Option<ModuleCode>,
) -> Result<ModuleId, Error> {
let module_map_rc = self.module_map.clone();
if let Some(code) = code {
let specifier = specifier.as_str().to_owned().into();
let scope = &mut self.handle_scope();
// true for main module
module_map_rc
.borrow_mut()
.new_es_module(scope, true, specifier, code, false)
.map_err(|e| match e {
ModuleError::Exception(exception) => {
let exception = v8::Local::new(scope, exception);
exception_to_err_result::<()>(scope, exception, false).unwrap_err()
}
ModuleError::Other(error) => error,
})?;
}
let mut load =
ModuleMap::load_main(module_map_rc.clone(), &specifier).await?;
while let Some(load_result) = load.next().await {
let (request, info) = load_result?;
let scope = &mut self.handle_scope();
load.register_and_recurse(scope, &request, info).map_err(
|e| match e {
ModuleError::Exception(exception) => {
let exception = v8::Local::new(scope, exception);
exception_to_err_result::<()>(scope, exception, false).unwrap_err()
}
ModuleError::Other(error) => error,
},
)?;
}
let root_id = load.root_module_id.expect("Root module should be loaded");
self.instantiate_module(root_id).map_err(|e| {
let scope = &mut self.handle_scope();
let exception = v8::Local::new(scope, e);
exception_to_err_result::<()>(scope, exception, false).unwrap_err()
})?;
Ok(root_id)
}
/// Asynchronously load specified ES module and all of its dependencies.
///
/// This method is meant to be used when loading some utility code that
/// might be later imported by the main module (ie. an entry point module).
///
/// User must call [`JsRuntime::mod_evaluate`] with returned `ModuleId`
/// manually after load is finished.
pub async fn load_side_module(
&mut self,
specifier: &ModuleSpecifier,
code: Option<ModuleCode>,
) -> Result<ModuleId, Error> {
let module_map_rc = self.module_map.clone();
if let Some(code) = code {
let specifier = specifier.as_str().to_owned().into();
let scope = &mut self.handle_scope();
// false for side module (not main module)
module_map_rc
.borrow_mut()
.new_es_module(scope, false, specifier, code, false)
.map_err(|e| match e {
ModuleError::Exception(exception) => {
let exception = v8::Local::new(scope, exception);
exception_to_err_result::<()>(scope, exception, false).unwrap_err()
}
ModuleError::Other(error) => error,
})?;
}
let mut load =
ModuleMap::load_side(module_map_rc.clone(), &specifier).await?;
while let Some(load_result) = load.next().await {
let (request, info) = load_result?;
let scope = &mut self.handle_scope();
load.register_and_recurse(scope, &request, info).map_err(
|e| match e {
ModuleError::Exception(exception) => {
let exception = v8::Local::new(scope, exception);
exception_to_err_result::<()>(scope, exception, false).unwrap_err()
}
ModuleError::Other(error) => error,
},
)?;
}
let root_id = load.root_module_id.expect("Root module should be loaded");
self.instantiate_module(root_id).map_err(|e| {
let scope = &mut self.handle_scope();
let exception = v8::Local::new(scope, e);
exception_to_err_result::<()>(scope, exception, false).unwrap_err()
})?;
Ok(root_id)
}
fn check_promise_rejections(&mut self) -> Result<(), Error> {
let state = self.inner.state.clone();
let scope = &mut self.handle_scope();
let state = state.borrow();
for realm in &state.known_realms {
realm.check_promise_rejections(scope)?;
}
Ok(())
}
// Polls pending ops and then runs `Deno.core.eventLoopTick` callback.
fn do_js_event_loop_tick(&mut self, cx: &mut Context) -> Result<(), Error> {
// Handle responses for each realm.
let state = self.inner.state.clone();
let isolate = &mut self.inner.v8_isolate;
let realm_count = state.borrow().known_realms.len();
for realm_idx in 0..realm_count {
let realm = state.borrow().known_realms.get(realm_idx).unwrap().clone();
let context_state = realm.state();
let mut context_state = context_state.borrow_mut();
let scope = &mut realm.handle_scope(isolate);
// We return async responses to JS in unbounded batches (may change),
// each batch is a flat vector of tuples:
// `[promise_id1, op_result1, promise_id2, op_result2, ...]`
// promise_id is a simple integer, op_result is an ops::OpResult
// which contains a value OR an error, encoded as a tuple.
// This batch is received in JS via the special `arguments` variable
// and then each tuple is used to resolve or reject promises
//
// This can handle 15 promises futures in a single batch without heap
// allocations.
let mut args: SmallVec<[v8::Local<v8::Value>; 32]> =
SmallVec::with_capacity(32);
loop {
let item = {
let next = std::pin::pin!(context_state.pending_ops.join_next());
let Poll::Ready(Some(item)) = next.poll(cx) else {
break;
};
item
};
let (promise_id, op_id, mut resp) = item.unwrap().into_inner();
state
.borrow()
.op_state
.borrow()
.tracker
.track_async_completed(op_id);
context_state.unrefed_ops.remove(&promise_id);
args.push(v8::Integer::new(scope, promise_id).into());
args.push(match resp.to_v8(scope) {
Ok(v) => v,
Err(e) => OpResult::Err(OpError::new(&|_| "TypeError", e.into()))
.to_v8(scope)
.unwrap(),
});
}
let has_tick_scheduled =
v8::Boolean::new(scope, self.inner.state.borrow().has_tick_scheduled);
args.push(has_tick_scheduled.into());
let js_event_loop_tick_cb_handle =
context_state.js_event_loop_tick_cb.clone().unwrap();
let tc_scope = &mut v8::TryCatch::new(scope);
let js_event_loop_tick_cb = js_event_loop_tick_cb_handle.open(tc_scope);
let this = v8::undefined(tc_scope).into();
drop(context_state);
js_event_loop_tick_cb.call(tc_scope, this, args.as_slice());
if let Some(exception) = tc_scope.exception() {
// TODO(@andreubotella): Returning here can cause async ops in other
// realms to never resolve.
return exception_to_err_result(tc_scope, exception, false);
}
if tc_scope.has_terminated() || tc_scope.is_execution_terminating() {
return Ok(());
}
}
Ok(())
}
}