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Revert "Add ability to attach arbitrary state to Isolate (#282)"

This patch introduces a bug that breaks Deno.

This reverts commit 457f7ae779.
This commit is contained in:
Bert Belder 2020-02-25 16:22:32 -08:00
parent 552ba261e2
commit eba98e7a5e
No known key found for this signature in database
GPG key ID: 7A77887B2E2ED461
3 changed files with 8 additions and 351 deletions

View file

@ -64,14 +64,14 @@ impl Context {
/// and run is compiled and run in this context. If another context /// and run is compiled and run in this context. If another context
/// is already entered, this old context is saved so it can be /// is already entered, this old context is saved so it can be
/// restored when the new context is exited. /// restored when the new context is exited.
pub fn enter(&mut self) { pub(crate) fn enter(&mut self) {
// TODO: enter/exit should be controlled by a scope. // TODO: enter/exit should be controlled by a scope.
unsafe { v8__Context__Enter(self) }; unsafe { v8__Context__Enter(self) };
} }
/// Exit this context. Exiting the current context restores the /// Exit this context. Exiting the current context restores the
/// context that was in place when entering the current context. /// context that was in place when entering the current context.
pub fn exit(&mut self) { pub(crate) fn exit(&mut self) {
// TODO: enter/exit should be controlled by a scope. // TODO: enter/exit should be controlled by a scope.
unsafe { v8__Context__Exit(self) }; unsafe { v8__Context__Exit(self) };
} }

View file

@ -19,24 +19,15 @@ use crate::StartupData;
use crate::String; use crate::String;
use crate::Value; use crate::Value;
use std::any::Any;
use std::any::TypeId;
use std::cell::RefCell;
use std::collections::HashMap;
use std::ffi::c_void; use std::ffi::c_void;
use std::mem::replace; use std::mem::replace;
use std::ops::Deref; use std::ops::Deref;
use std::ops::DerefMut; use std::ops::DerefMut;
use std::ptr::null_mut; use std::ptr::null_mut;
use std::ptr::NonNull; use std::ptr::NonNull;
use std::rc::Rc;
use std::sync::Arc; use std::sync::Arc;
use std::sync::Mutex; use std::sync::Mutex;
/// Because there are only 3 embedder slots, we use this store multiple states.
/// We have many different types of states in Deno due to the core/cli split.
type States = HashMap<TypeId, Rc<RefCell<dyn Any>>>;
pub type MessageCallback = extern "C" fn(Local<Message>, Local<Value>); pub type MessageCallback = extern "C" fn(Local<Message>, Local<Value>);
pub type PromiseRejectCallback = extern "C" fn(PromiseRejectMessage); pub type PromiseRejectCallback = extern "C" fn(PromiseRejectMessage);
@ -142,12 +133,6 @@ extern "C" {
); );
} }
enum InternalSlots {
Annex = 0,
States,
Total,
}
#[repr(C)] #[repr(C)]
/// Isolate represents an isolated instance of the V8 engine. V8 isolates have /// Isolate represents an isolated instance of the V8 engine. V8 isolates have
/// completely separate states. Objects from one isolate must not be used in /// completely separate states. Objects from one isolate must not be used in
@ -182,79 +167,29 @@ impl Isolate {
} }
unsafe fn set_annex(&mut self, ptr: *mut IsolateAnnex) { unsafe fn set_annex(&mut self, ptr: *mut IsolateAnnex) {
self.set_data_int(InternalSlots::Annex as _, ptr as *mut c_void); v8__Isolate__SetData(self, 0, ptr as *mut c_void)
} }
fn get_annex(&self) -> *mut IsolateAnnex { fn get_annex(&self) -> *mut IsolateAnnex {
self.get_data_int(InternalSlots::Annex as _) as *mut _ unsafe { v8__Isolate__GetData(self, 0) as *mut _ }
} }
/// Associate embedder-specific data with the isolate. |slot| has to be /// Associate embedder-specific data with the isolate. |slot| has to be
/// between 0 and GetNumberOfDataSlots() - 1. /// between 0 and GetNumberOfDataSlots() - 1.
pub unsafe fn set_data(&mut self, slot: u32, ptr: *mut c_void) { pub unsafe fn set_data(&mut self, slot: u32, ptr: *mut c_void) {
self.set_data_int(slot + InternalSlots::Total as u32, ptr) v8__Isolate__SetData(self, slot + 1, ptr)
}
unsafe fn set_data_int(&mut self, slot: u32, ptr: *mut c_void) {
v8__Isolate__SetData(self, slot, ptr)
} }
/// Retrieve embedder-specific data from the isolate. /// Retrieve embedder-specific data from the isolate.
/// Returns NULL if SetData has never been called for the given |slot|. /// Returns NULL if SetData has never been called for the given |slot|.
pub fn get_data(&self, slot: u32) -> *mut c_void { pub fn get_data(&self, slot: u32) -> *mut c_void {
self.get_data_int(slot + InternalSlots::Total as u32) unsafe { v8__Isolate__GetData(self, slot + 1) }
}
fn get_data_int(&self, slot: u32) -> *mut c_void {
unsafe { v8__Isolate__GetData(self, slot) }
} }
/// Returns the maximum number of available embedder data slots. Valid slots /// Returns the maximum number of available embedder data slots. Valid slots
/// are in the range of 0 - GetNumberOfDataSlots() - 1. /// are in the range of 0 - GetNumberOfDataSlots() - 1.
pub fn get_number_of_data_slots(&self) -> u32 { pub fn get_number_of_data_slots(&self) -> u32 {
unsafe { unsafe { v8__Isolate__GetNumberOfDataSlots(self) - 1 }
v8__Isolate__GetNumberOfDataSlots(self) - InternalSlots::Total as u32
}
}
pub fn state_add<S>(&mut self, state: S)
where
S: 'static + Sized,
{
let mut ptr = self.get_data_int(InternalSlots::States as _) as *mut States;
if ptr.is_null() {
assert!(ptr.is_null());
let states = Box::new(HashMap::new());
ptr = Box::into_raw(states);
unsafe { self.set_data_int(InternalSlots::States as _, ptr as *mut _) };
}
let mut states = unsafe { Box::from_raw(ptr) };
let type_id = TypeId::of::<S>();
let existing = states.insert(type_id, Rc::new(RefCell::new(state)));
assert!(existing.is_none());
// ptr is still stored in Isolate's embedder slot.
let ptr2 = Box::into_raw(states);
assert_eq!(ptr, ptr2);
}
pub fn state_get<S>(&self) -> Rc<RefCell<S>>
where
S: 'static + Sized,
{
let ptr = self.get_data_int(InternalSlots::States as _) as *mut States;
let states = unsafe { Box::from_raw(ptr) };
let type_id = TypeId::of::<S>();
let state = states.get(&type_id).unwrap();
// TODO(ry) how to change Rc<RefCell<(dyn Any + 'static)>> into
// Rc<RefCell<S>> without transmute?
#[allow(clippy::transmute_ptr_to_ptr)]
let state = unsafe { std::mem::transmute::<_, &Rc<RefCell<S>>>(state) };
let ptr2 = Box::into_raw(states); // because isolate slot still has ptr.
assert_eq!(ptr, ptr2);
state.clone()
} }
/// Sets this isolate as the entered one for the current thread. /// Sets this isolate as the entered one for the current thread.
@ -361,13 +296,6 @@ impl Isolate {
// No test case in rusty_v8 show this, but there have been situations in // No test case in rusty_v8 show this, but there have been situations in
// deno where dropping Annex before the states causes a segfault. // deno where dropping Annex before the states causes a segfault.
let ptr = self.get_data_int(InternalSlots::States as _) as *mut States;
if !ptr.is_null() {
let states = Box::from_raw(ptr);
self.set_data_int(InternalSlots::States as _, std::ptr::null_mut());
drop(states);
}
v8__Isolate__Dispose(self) v8__Isolate__Dispose(self)
} }
} }
@ -422,7 +350,7 @@ impl IsolateHandle {
unsafe { unsafe {
{ {
let _lock = (*annex_ptr).mutex.lock().unwrap(); let _lock = (*annex_ptr).mutex.lock().unwrap();
isolate.set_data(InternalSlots::Annex as _, null_mut()); isolate.set_data(0, null_mut());
let isolate_ptr = replace(&mut (*annex_ptr).isolate, null_mut()); let isolate_ptr = replace(&mut (*annex_ptr).isolate, null_mut());
assert_eq!(isolate as *mut _, isolate_ptr); assert_eq!(isolate as *mut _, isolate_ptr);
} }

View file

@ -1,271 +0,0 @@
//! This shows a pattern for adding state to an Isolate. The pattern is used
//! extensively in Deno.
use core::ops::Deref;
use core::ops::DerefMut;
use rusty_v8 as v8;
#[test]
fn isolate_with_state1() {
init_v8();
let mut isolate1 = Isolate1::new();
isolate1.setup();
assert_eq!(0, isolate1.count());
assert_eq!(0, isolate1.js_count());
isolate1.exec("change_state()");
assert_eq!(1, isolate1.count());
assert_eq!(1, isolate1.js_count());
isolate1.exec("change_state()");
assert_eq!(2, isolate1.count());
assert_eq!(2, isolate1.js_count());
}
#[test]
fn isolate_with_state2() {
init_v8();
let mut isolate2 = Isolate2::new();
isolate2.setup();
assert_eq!(0, isolate2.count());
assert_eq!(0, isolate2.js_count());
assert_eq!(0, isolate2.count2());
assert_eq!(0, isolate2.js_count2());
isolate2.exec("change_state2()");
assert_eq!(0, isolate2.count());
assert_eq!(0, isolate2.js_count());
assert_eq!(1, isolate2.count2());
assert_eq!(1, isolate2.js_count2());
isolate2.exec("change_state2()");
assert_eq!(0, isolate2.count());
assert_eq!(0, isolate2.js_count());
assert_eq!(2, isolate2.count2());
assert_eq!(2, isolate2.js_count2());
isolate2.exec("change_state()");
assert_eq!(1, isolate2.count());
assert_eq!(1, isolate2.js_count());
assert_eq!(2, isolate2.count2());
assert_eq!(2, isolate2.js_count2());
}
struct State1 {
pub magic_number: usize,
pub count: usize,
pub js_count: v8::Global<v8::Integer>,
}
struct Isolate1(v8::OwnedIsolate);
impl Isolate1 {
fn new() -> Isolate1 {
let mut params = v8::Isolate::create_params();
params.set_array_buffer_allocator(v8::new_default_allocator());
let mut isolate = v8::Isolate::new(params);
let state = State1 {
magic_number: 0xCAFE_BABE,
count: 0,
js_count: v8::Global::new(),
};
isolate.state_add(state);
Isolate1(isolate)
}
pub fn setup(&mut self) {
let mut hs = v8::HandleScope::new(&mut self.0);
let scope = hs.enter();
let mut context = v8::Context::new(scope);
context.enter();
let global = context.global(scope);
{
let js_count = v8::Integer::new(scope, 0);
let state = scope.isolate().state_get::<State1>();
assert_eq!(state.borrow().magic_number, 0xCAFE_BABE);
state.borrow_mut().js_count.set(scope, js_count);
}
let mut change_state_tmpl =
v8::FunctionTemplate::new(scope, Self::change_state);
let change_state_val =
change_state_tmpl.get_function(scope, context).unwrap();
global.set(
context,
v8::String::new(scope, "change_state").unwrap().into(),
change_state_val.into(),
);
}
pub fn exec(&mut self, src: &str) {
let mut hs = v8::HandleScope::new(&mut self.0);
let scope = hs.enter();
let context = scope.get_current_context().unwrap();
let source = v8::String::new(scope, src).unwrap();
let mut script = v8::Script::compile(scope, context, source, None).unwrap();
script.run(scope, context);
}
fn change_state(
scope: v8::FunctionCallbackScope,
_args: v8::FunctionCallbackArguments,
_rv: v8::ReturnValue,
) {
let state = scope.isolate().state_get::<State1>();
let mut state = state.borrow_mut();
assert_eq!(state.magic_number, 0xCAFE_BABE);
state.count += 1;
let js_count = state.js_count.get(scope).unwrap();
let js_count_value = js_count.value() as i32;
let js_count_next = v8::Integer::new(scope, js_count_value + 1);
state.js_count.set(scope, js_count_next);
}
fn count(&self) -> usize {
let state = self.0.state_get::<State1>();
let state = state.borrow();
assert_eq!(state.magic_number, 0xCAFE_BABE);
state.count
}
fn js_count(&mut self) -> i64 {
let mut hs = v8::HandleScope::new(&mut self.0);
let scope = hs.enter();
let state = scope.isolate().state_get::<State1>();
let state = state.borrow_mut();
let js_count = state.js_count.get(scope).unwrap();
js_count.value()
}
}
// TODO(ry) Useless boilerplate!
impl v8::InIsolate for Isolate1 {
fn isolate(&mut self) -> &mut v8::Isolate {
&mut self.0
}
}
impl Deref for Isolate1 {
type Target = v8::Isolate;
fn deref(&self) -> &v8::Isolate {
&self.0
}
}
impl DerefMut for Isolate1 {
fn deref_mut(&mut self) -> &mut v8::Isolate {
&mut self.0
}
}
struct State2 {
pub count2: usize,
pub js_count2: v8::Global<v8::Integer>,
pub magic_number: u32,
}
struct Isolate2(Isolate1);
impl Isolate2 {
fn new() -> Isolate2 {
let mut isolate1 = Isolate1::new();
let state2 = State2 {
count2: 0,
js_count2: v8::Global::new(),
magic_number: 0xDEAD_BEEF,
};
isolate1.state_add(state2);
Isolate2(isolate1)
}
fn setup(&mut self) {
self.0.setup();
let mut hs = v8::HandleScope::new(&mut self.0);
let scope = hs.enter();
let context = scope.get_current_context().unwrap();
let global = context.global(scope);
{
let js_count2 = v8::Integer::new(scope, 0);
let state = scope.isolate().state_get::<State2>();
assert_eq!(state.borrow().magic_number, 0xDEAD_BEEF);
state.borrow_mut().js_count2.set(scope, js_count2);
}
let mut change_state_tmpl =
v8::FunctionTemplate::new(scope, Self::change_state2);
let change_state_val =
change_state_tmpl.get_function(scope, context).unwrap();
global.set(
context,
v8::String::new(scope, "change_state2").unwrap().into(),
change_state_val.into(),
);
}
pub fn exec(&mut self, src: &str) {
self.0.exec(src)
}
fn change_state2(
scope: v8::FunctionCallbackScope,
_args: v8::FunctionCallbackArguments,
_rv: v8::ReturnValue,
) {
let state = scope.isolate().state_get::<State2>();
let mut state = state.borrow_mut();
assert_eq!(state.magic_number, 0xDEAD_BEEF);
state.count2 += 1;
let js_count2 = state.js_count2.get(scope).unwrap();
let js_count2_value = js_count2.value() as i32;
let js_count2_next = v8::Integer::new(scope, js_count2_value + 1);
state.js_count2.set(scope, js_count2_next);
}
fn count2(&self) -> usize {
let state = self.0.state_get::<State2>();
let state = state.borrow();
assert_eq!(state.magic_number, 0xDEAD_BEEF);
state.count2
}
fn js_count2(&mut self) -> i64 {
let mut hs = v8::HandleScope::new(&mut self.0);
let scope = hs.enter();
let state = scope.isolate().state_get::<State2>();
let state = state.borrow_mut();
assert_eq!(state.magic_number, 0xDEAD_BEEF);
let js_count2 = state.js_count2.get(scope).unwrap();
js_count2.value()
}
}
impl Deref for Isolate2 {
type Target = Isolate1;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for Isolate2 {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
fn init_v8() {
use std::sync::Once;
static INIT_V8: Once = Once::new();
INIT_V8.call_once(|| {
v8::V8::initialize_platform(v8::new_default_platform());
v8::V8::initialize();
});
}