Add support for Platform::pump_message_loop and Platform::run_idle_tasks (#706)

Co-authored-by: Ben Noordhuis <info@bnoordhuis.nl>

examples/hello_world.rs

@@ -2,7 +2,7 @@ use rusty_v8 as v8;
 
 fn main() {
   // Initialize V8.
-  let platform = v8::new_default_platform().unwrap();
+  let platform = v8::new_default_platform(0, false).make_shared();
   v8::V8::initialize_platform(platform);
   v8::V8::initialize();
 

examples/process.rs

@@ -19,7 +19,7 @@ fn log_callback(
 
 fn main() {
   // Initialize V8.
-  let platform = v8::new_default_platform().unwrap();
+  let platform = v8::new_default_platform(0, false).make_shared();
   v8::V8::initialize_platform(platform);
   v8::V8::initialize();
 

examples/shell.rs

@@ -2,7 +2,7 @@ use rusty_v8 as v8;
 
 fn main() {
   // Initialize V8.
-  let platform = v8::new_default_platform().unwrap();
+  let platform = v8::new_default_platform(0, false).make_shared();
   v8::V8::initialize_platform(platform);
   v8::V8::initialize();
 
@@ -79,11 +79,15 @@ fn run_main(
         let script: &str = &args[i + 1];
         skip_next = true;
 
-        // TODO: pump event loop (not implemented on rusty_v8?)
-        // while v8::Platform::pump_message_loop(&platform, isolate) {
-        //   // do nothing
-        // }
         execute_string(scope, script, "unnamed", false, true);
+
+        while v8::Platform::pump_message_loop(
+          &v8::V8::get_current_platform(),
+          scope,
+          false,
+        ) {
+          // do nothing
+        }
       }
       arg => {
         if arg.starts_with("--") {
@@ -94,6 +98,14 @@ fn run_main(
         // Use all other arguments as names of files to load and run.
         let script = std::fs::read_to_string(arg).expect("failed to read file");
         execute_string(scope, &script, arg, false, true);
+
+        while v8::Platform::pump_message_loop(
+          &v8::V8::get_current_platform(),
+          scope,
+          false,
+        ) {
+          // do nothing
+        }
       }
     }
   }

src/V8.rs

@@ -7,7 +7,7 @@ use std::sync::Mutex;
 use std::vec::Vec;
 
 use crate::platform::Platform;
-use crate::support::UniqueRef;
+use crate::support::SharedRef;
 use crate::support::UnitType;
 
 extern "C" {
@@ -61,24 +61,26 @@ where
   }
 }
 
-#[derive(Debug, Eq, PartialEq)]
+#[derive(Debug)]
 enum GlobalState {
   Uninitialized,
-  PlatformInitialized,
-  Initialized,
-  Disposed,
+  PlatformInitialized(SharedRef<Platform>),
+  Initialized(SharedRef<Platform>),
+  Disposed(SharedRef<Platform>),
   PlatformShutdown,
 }
 use GlobalState::*;
 
 lazy_static! {
-  static ref GLOBAL_STATE: Mutex<GlobalState> =
-    Mutex::new(GlobalState::Uninitialized);
+  static ref GLOBAL_STATE: Mutex<GlobalState> = Mutex::new(Uninitialized);
 }
 
 pub fn assert_initialized() {
   let global_state_guard = GLOBAL_STATE.lock().unwrap();
-  assert_eq!(*global_state_guard, Initialized);
+  match *global_state_guard {
+    Initialized(_) => {}
+    _ => panic!("Invalid global state"),
+  };
 }
 
 /// Pass the command line arguments to v8.
@@ -173,25 +175,41 @@ pub fn get_version() -> &'static str {
   c_str.to_str().unwrap()
 }
 
-// TODO: V8::InitializePlatform does not actually take a UniquePtr but rather
-// a raw pointer. This means that the Platform object is not released when
-// V8::ShutdownPlatform is called.
 /// Sets the v8::Platform to use. This should be invoked before V8 is
 /// initialized.
-pub fn initialize_platform(platform: UniqueRef<Platform>) {
+pub fn initialize_platform(platform: SharedRef<Platform>) {
   let mut global_state_guard = GLOBAL_STATE.lock().unwrap();
-  assert_eq!(*global_state_guard, Uninitialized);
-  unsafe { v8__V8__InitializePlatform(platform.into_raw()) };
-  *global_state_guard = PlatformInitialized;
+  *global_state_guard = match *global_state_guard {
+    Uninitialized => PlatformInitialized(platform.clone()),
+    _ => panic!("Invalid global state"),
+  };
+
+  {
+    unsafe {
+      v8__V8__InitializePlatform(&*platform as *const Platform as *mut _)
+    };
+  }
 }
 
 /// Initializes V8. This function needs to be called before the first Isolate
 /// is created. It always returns true.
 pub fn initialize() {
   let mut global_state_guard = GLOBAL_STATE.lock().unwrap();
-  assert_eq!(*global_state_guard, PlatformInitialized);
-  unsafe { v8__V8__Initialize() };
-  *global_state_guard = Initialized;
+  *global_state_guard = match *global_state_guard {
+    PlatformInitialized(ref platform) => Initialized(platform.clone()),
+    _ => panic!("Invalid global state"),
+  };
+  unsafe { v8__V8__Initialize() }
+}
+
+/// Sets the v8::Platform to use. This should be invoked before V8 is
+/// initialized.
+pub fn get_current_platform() -> SharedRef<Platform> {
+  let global_state_guard = GLOBAL_STATE.lock().unwrap();
+  match *global_state_guard {
+    Initialized(ref platform) => platform.clone(),
+    _ => panic!("Invalid global state"),
+  }
 }
 
 /// Releases any resources used by v8 and stops any utility threads
@@ -208,9 +226,11 @@ pub fn initialize() {
 /// to a crash.
 pub unsafe fn dispose() -> bool {
   let mut global_state_guard = GLOBAL_STATE.lock().unwrap();
-  assert_eq!(*global_state_guard, Initialized);
+  *global_state_guard = match *global_state_guard {
+    Initialized(ref platform) => Disposed(platform.clone()),
+    _ => panic!("Invalid global state"),
+  };
   assert!(v8__V8__Dispose());
-  *global_state_guard = Disposed;
   true
 }
 
@@ -218,7 +238,10 @@ pub unsafe fn dispose() -> bool {
 /// V8 was disposed.
 pub fn shutdown_platform() {
   let mut global_state_guard = GLOBAL_STATE.lock().unwrap();
-  assert_eq!(*global_state_guard, Disposed);
+  // First shutdown platform, then drop platform
   unsafe { v8__V8__ShutdownPlatform() };
-  *global_state_guard = PlatformShutdown;
+  *global_state_guard = match *global_state_guard {
+    Disposed(_) => PlatformShutdown,
+    _ => panic!("Invalid global state"),
+  };
 }

src/binding.cc

@@ -2028,18 +2028,64 @@ v8::StartupData v8__SnapshotCreator__CreateBlob(
   return self->CreateBlob(function_code_handling);
 }
 
-v8::Platform* v8__platform__NewDefaultPlatform() {
-  // TODO(bnoordhuis) Support optional arguments.
-  return v8::platform::NewDefaultPlatform().release();
+v8::Platform* v8__Platform__NewDefaultPlatform(int thread_pool_size,
+                                               bool idle_task_support) {
+  return v8::platform::NewDefaultPlatform(
+             thread_pool_size,
+             idle_task_support ? v8::platform::IdleTaskSupport::kEnabled
+                               : v8::platform::IdleTaskSupport::kDisabled,
+             v8::platform::InProcessStackDumping::kDisabled, nullptr)
+      .release();
 }
 
-v8::Platform* v8__platform__NewSingleThreadedDefaultPlatform() {
-  // TODO(bnoordhuis) Support optional arguments.
-  return v8::platform::NewSingleThreadedDefaultPlatform().release();
+v8::Platform* v8__Platform__NewSingleThreadedDefaultPlatform(
+    bool idle_task_support) {
+  return v8::platform::NewSingleThreadedDefaultPlatform(
+             idle_task_support ? v8::platform::IdleTaskSupport::kEnabled
+                               : v8::platform::IdleTaskSupport::kDisabled,
+             v8::platform::InProcessStackDumping::kDisabled, nullptr)
+      .release();
+}
+
+bool v8__Platform__PumpMessageLoop(v8::Platform* platform, v8::Isolate* isolate,
+                                   bool wait_for_work) {
+  return v8::platform::PumpMessageLoop(
+      platform, isolate,
+      wait_for_work ? v8::platform::MessageLoopBehavior::kWaitForWork
+                    : v8::platform::MessageLoopBehavior::kDoNotWait);
+}
+
+void v8__Platform__RunIdleTasks(v8::Platform* platform, v8::Isolate* isolate,
+                                double idle_time_in_seconds) {
+  v8::platform::RunIdleTasks(platform, isolate, idle_time_in_seconds);
 }
 
 void v8__Platform__DELETE(v8::Platform* self) { delete self; }
 
+two_pointers_t std__shared_ptr__v8__Platform__CONVERT__std__unique_ptr(
+    v8::Platform* unique_ptr) {
+  return make_pod<two_pointers_t>(std::shared_ptr<v8::Platform>(unique_ptr));
+}
+
+v8::Platform* std__shared_ptr__v8__Platform__get(
+    const std::shared_ptr<v8::Platform>& ptr) {
+  return ptr.get();
+}
+
+two_pointers_t std__shared_ptr__v8__Platform__COPY(
+    const std::shared_ptr<v8::Platform>& ptr) {
+  return make_pod<two_pointers_t>(ptr);
+}
+
+void std__shared_ptr__v8__Platform__reset(std::shared_ptr<v8::Platform>* ptr) {
+  ptr->reset();
+}
+
+long std__shared_ptr__v8__Platform__use_count(
+    const std::shared_ptr<v8::Platform>& ptr) {
+  return ptr.use_count();
+}
+
 void v8_inspector__V8Inspector__Channel__BASE__sendResponse(
     v8_inspector::V8Inspector::Channel* self, int callId,
     v8_inspector::StringBuffer* message);

src/lib.rs

@@ -5,7 +5,7 @@
 //! ```rust
 //! use rusty_v8 as v8;
 //!
-//! let platform = v8::new_default_platform().unwrap();
+//! let platform = v8::new_default_platform(0, false).make_shared();
 //! v8::V8::initialize_platform(platform);
 //! v8::V8::initialize();
 //!

src/platform.rs

@@ -1,31 +1,181 @@
+use crate::support::int;
+use crate::Isolate;
+
+use crate::support::long;
 use crate::support::Opaque;
+use crate::support::Shared;
+use crate::support::SharedPtrBase;
+use crate::support::SharedRef;
 use crate::support::UniquePtr;
+use crate::support::UniqueRef;
 
 extern "C" {
-  fn v8__platform__NewDefaultPlatform() -> *mut Platform;
-  fn v8__platform__NewSingleThreadedDefaultPlatform() -> *mut Platform;
+  fn v8__Platform__NewDefaultPlatform(
+    thread_pool_size: int,
+    idle_task_support: bool,
+  ) -> *mut Platform;
+  fn v8__Platform__NewSingleThreadedDefaultPlatform(
+    idle_task_support: bool,
+  ) -> *mut Platform;
   fn v8__Platform__DELETE(this: *mut Platform);
-}
 
-/// Returns a new instance of the default v8::Platform implementation.
-pub fn new_default_platform() -> UniquePtr<Platform> {
-  unsafe { UniquePtr::from_raw(v8__platform__NewDefaultPlatform()) }
-}
+  fn v8__Platform__PumpMessageLoop(
+    platform: *mut Platform,
+    isolate: *mut Isolate,
+    wait_for_work: bool,
+  ) -> bool;
 
-/// The same as new_default_platform() but disables the worker thread pool.
-/// It must be used with the --single-threaded V8 flag.
-pub fn new_single_threaded_default_platform() -> UniquePtr<Platform> {
-  unsafe {
-    UniquePtr::from_raw(v8__platform__NewSingleThreadedDefaultPlatform())
-  }
+  fn v8__Platform__RunIdleTasks(
+    platform: *mut Platform,
+    isolate: *mut Isolate,
+    idle_time_in_seconds: f64,
+  );
+
+  fn std__shared_ptr__v8__Platform__CONVERT__std__unique_ptr(
+    unique_ptr: UniquePtr<Platform>,
+  ) -> SharedPtrBase<Platform>;
+  fn std__shared_ptr__v8__Platform__get(
+    ptr: *const SharedPtrBase<Platform>,
+  ) -> *mut Platform;
+  fn std__shared_ptr__v8__Platform__COPY(
+    ptr: *const SharedPtrBase<Platform>,
+  ) -> SharedPtrBase<Platform>;
+  fn std__shared_ptr__v8__Platform__reset(ptr: *mut SharedPtrBase<Platform>);
+  fn std__shared_ptr__v8__Platform__use_count(
+    ptr: *const SharedPtrBase<Platform>,
+  ) -> long;
 }
 
 #[repr(C)]
 #[derive(Debug)]
 pub struct Platform(Opaque);
 
-impl Drop for Platform {
-  fn drop(&mut self) {
-    unsafe { v8__Platform__DELETE(self) }
+/// Returns a new instance of the default v8::Platform implementation.
+///
+/// |thread_pool_size| is the number of worker threads to allocate for
+/// background jobs. If a value of zero is passed, a suitable default
+/// based on the current number of processors online will be chosen.
+/// If |idle_task_support| is enabled then the platform will accept idle
+/// tasks (IdleTasksEnabled will return true) and will rely on the embedder
+/// calling v8::platform::RunIdleTasks to process the idle tasks.
+pub fn new_default_platform(
+  thread_pool_size: u32,
+  idle_task_support: bool,
+) -> UniqueRef<Platform> {
+  Platform::new(thread_pool_size, idle_task_support)
+}
+
+/// The same as new_default_platform() but disables the worker thread pool.
+/// It must be used with the --single-threaded V8 flag.
+///
+/// If |idle_task_support| is enabled then the platform will accept idle
+/// tasks (IdleTasksEnabled will return true) and will rely on the embedder
+/// calling v8::platform::RunIdleTasks to process the idle tasks.
+pub fn new_single_threaded_default_platform(
+  idle_task_support: bool,
+) -> UniqueRef<Platform> {
+  Platform::new_single_threaded(idle_task_support)
+}
+
+impl Platform {
+  /// Returns a new instance of the default v8::Platform implementation.
+  ///
+  /// |thread_pool_size| is the number of worker threads to allocate for
+  /// background jobs. If a value of zero is passed, a suitable default
+  /// based on the current number of processors online will be chosen.
+  /// If |idle_task_support| is enabled then the platform will accept idle
+  /// tasks (IdleTasksEnabled will return true) and will rely on the embedder
+  /// calling v8::platform::RunIdleTasks to process the idle tasks.
+  pub fn new(
+    thread_pool_size: u32,
+    idle_task_support: bool,
+  ) -> UniqueRef<Self> {
+    unsafe {
+      UniqueRef::from_raw(v8__Platform__NewDefaultPlatform(
+        thread_pool_size.min(16) as i32,
+        idle_task_support,
+      ))
+    }
+  }
+
+  /// The same as new() but disables the worker thread pool.
+  /// It must be used with the --single-threaded V8 flag.
+  ///
+  /// If |idle_task_support| is enabled then the platform will accept idle
+  /// tasks (IdleTasksEnabled will return true) and will rely on the embedder
+  /// calling v8::platform::RunIdleTasks to process the idle tasks.
+  pub fn new_single_threaded(idle_task_support: bool) -> UniqueRef<Self> {
+    unsafe {
+      UniqueRef::from_raw(v8__Platform__NewSingleThreadedDefaultPlatform(
+        idle_task_support,
+      ))
+    }
+  }
+}
+
+impl Platform {
+  /// Pumps the message loop for the given isolate.
+  ///
+  /// The caller has to make sure that this is called from the right thread.
+  /// Returns true if a task was executed, and false otherwise. If the call to
+  /// PumpMessageLoop is nested within another call to PumpMessageLoop, only
+  /// nestable tasks may run. Otherwise, any task may run. Unless requested through
+  /// the |wait_for_work| parameter, this call does not block if no task is pending.
+  pub fn pump_message_loop(
+    platform: &SharedRef<Self>,
+    isolate: &mut Isolate,
+    wait_for_work: bool,
+  ) -> bool {
+    unsafe {
+      v8__Platform__PumpMessageLoop(
+        &**platform as *const Self as *mut _,
+        isolate,
+        wait_for_work,
+      )
+    }
+  }
+
+  /// Runs pending idle tasks for at most |idle_time_in_seconds| seconds.
+  ///
+  /// The caller has to make sure that this is called from the right thread.
+  /// This call does not block if no task is pending.
+  pub fn run_idle_tasks(
+    platform: &SharedRef<Self>,
+    isolate: &mut Isolate,
+    idle_time_in_seconds: f64,
+  ) {
+    unsafe {
+      v8__Platform__RunIdleTasks(
+        &**platform as *const Self as *mut _,
+        isolate,
+        idle_time_in_seconds,
+      )
+    }
+  }
+}
+
+impl Shared for Platform {
+  fn from_unique_ptr(unique_ptr: UniquePtr<Self>) -> SharedPtrBase<Self> {
+    unsafe {
+      std__shared_ptr__v8__Platform__CONVERT__std__unique_ptr(unique_ptr)
+    }
+  }
+  fn get(ptr: &SharedPtrBase<Self>) -> *const Self {
+    unsafe { std__shared_ptr__v8__Platform__get(ptr) }
+  }
+  fn clone(ptr: &SharedPtrBase<Self>) -> SharedPtrBase<Self> {
+    unsafe { std__shared_ptr__v8__Platform__COPY(ptr) }
+  }
+  fn reset(ptr: &mut SharedPtrBase<Self>) {
+    unsafe { std__shared_ptr__v8__Platform__reset(ptr) }
+  }
+  fn use_count(ptr: &SharedPtrBase<Self>) -> long {
+    unsafe { std__shared_ptr__v8__Platform__use_count(ptr) }
+  }
+}
+
+impl Drop for Platform {
+  fn drop(&mut self) {
+    unsafe { v8__Platform__DELETE(self) };
   }
 }

src/scope.rs

@@ -1727,7 +1727,7 @@ mod tests {
   fn initialize_v8() {
     static INIT: Once = Once::new();
     INIT.call_once(|| {
-      V8::initialize_platform(new_default_platform().unwrap());
+      V8::initialize_platform(new_default_platform(0, false).make_shared());
       V8::initialize();
     });
   }

tests/slots.rs

@@ -28,7 +28,9 @@ impl CoreIsolate {
   fn new(drop_count: Rc<AtomicUsize>) -> CoreIsolate {
     static START: Once = Once::new();
     START.call_once(|| {
-      v8::V8::initialize_platform(v8::new_default_platform().unwrap());
+      v8::V8::initialize_platform(
+        v8::new_default_platform(0, false).make_shared(),
+      );
       v8::V8::initialize();
     });
     let mut isolate = v8::Isolate::new(Default::default());

tests/test_api.rs

@@ -31,7 +31,9 @@ fn setup() -> SetupGuard {
     ))
     .is_ok());
     v8::V8::set_flags_from_string("--expose_gc --harmony-import-assertions");
-    v8::V8::initialize_platform(v8::new_default_platform().unwrap());
+    v8::V8::initialize_platform(
+      v8::new_default_platform(0, false).make_shared(),
+    );
     v8::V8::initialize();
   });
   SetupGuard {}

tests/test_api_entropy_source.rs

@@ -19,7 +19,7 @@ fn set_entropy_source() {
     true
   });
 
-  v8::V8::initialize_platform(v8::new_default_platform().unwrap());
+  v8::V8::initialize_platform(v8::new_default_platform(0, false).make_shared());
   v8::V8::initialize();
 
   // Assumes that every isolate creates a PRNG from scratch, which is currently true.

tests/test_api_flags.rs

@@ -5,7 +5,7 @@ use rusty_v8 as v8;
 #[test]
 fn set_flags_from_string() {
   v8::V8::set_flags_from_string("--use_strict");
-  v8::V8::initialize_platform(v8::new_default_platform().unwrap());
+  v8::V8::initialize_platform(v8::new_default_platform(0, false).make_shared());
   v8::V8::initialize();
   let isolate = &mut v8::Isolate::new(Default::default());
   let scope = &mut v8::HandleScope::new(isolate);

tests/test_platform_atomics_pump_message_loop.rs

@@ -0,0 +1,53 @@
+use rusty_v8 as v8;
+
+#[test]
+fn atomics_pump_message_loop() {
+  v8::V8::set_flags_from_string("--harmony-top-level-await --allow-natives-syntax --harmony-sharedarraybuffer");
+  v8::V8::initialize_platform(v8::new_default_platform(0, false).make_shared());
+  v8::V8::initialize();
+  let isolate = &mut v8::Isolate::new(Default::default());
+  let scope = &mut v8::HandleScope::new(isolate);
+  let context = v8::Context::new(scope);
+  let scope = &mut v8::ContextScope::new(scope, context);
+  let source = r#"
+    function assertEquals(a, b) {
+      if (a === b) return;
+      throw a + " does not equal " + b;
+    }
+
+    const sab = new SharedArrayBuffer(16);
+    const i32a = new Int32Array(sab);
+
+    let resolved = false;
+    (function() {
+      const result = Atomics.waitAsync(i32a, 0, 0);
+      result.value.then(
+        (value) => { assertEquals("ok", value); resolved = true; },
+        () => { assertUnreachable();
+      });
+    })();
+
+    const notify_return_value = Atomics.notify(i32a, 0, 1);
+    assertEquals(1, notify_return_value);
+    assertEquals(0, %AtomicsNumWaitersForTesting(i32a, 0));
+    assertEquals(1, %AtomicsNumUnresolvedAsyncPromisesForTesting(i32a, 0));
+  "#;
+  let source = v8::String::new(scope, source).unwrap();
+  let script = v8::Script::compile(scope, source, None).unwrap();
+  script.run(scope).unwrap();
+
+  while v8::Platform::pump_message_loop(
+    &v8::V8::get_current_platform(),
+    scope,
+    false,
+  ) {
+    // do nothing
+  }
+
+  let source2 = r#"
+    assertEquals(0, %AtomicsNumUnresolvedAsyncPromisesForTesting(i32a, 0));
+  "#;
+  let source2 = v8::String::new(scope, source2).unwrap();
+  let script2 = v8::Script::compile(scope, source2, None).unwrap();
+  script2.run(scope).unwrap();
+}

tests/test_single_threaded_default_platform.rs

@@ -4,7 +4,7 @@ use rusty_v8 as v8;
 fn single_threaded_default_platform() {
   v8::V8::set_flags_from_string("--single_threaded");
   v8::V8::initialize_platform(
-    v8::new_single_threaded_default_platform().unwrap(),
+    v8::new_single_threaded_default_platform(false).make_shared(),
   );
   v8::V8::initialize();