Auto merge of #344 - jdm:shutdown, r=nox

Call JS_ShutDown when all runtimes have been dropped.

This will enable better investigation of Servo's shutdown behaviour, since currently all of the JS helper threads just sit there until process exit.

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Author: bors-servo

src/rust.rs

@@ -16,13 +16,14 @@ use std::default::Default;
 use std::ops::{Deref, DerefMut};
 use std::cell::{Cell, UnsafeCell};
 use std::marker::PhantomData;
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use consts::{JSCLASS_RESERVED_SLOTS_MASK, JSCLASS_GLOBAL_SLOT_COUNT};
 use consts::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
 use jsapi;
 use jsapi::{AutoIdVector, AutoObjectVector, CallArgs, CompartmentOptions, ContextFriendFields};
 use jsapi::{Evaluate2, Handle, HandleBase, HandleObject, HandleValue, HandleValueArray, Heap};
 use jsapi::{HeapObjectPostBarrier, HeapValuePostBarrier, InitSelfHostedCode, IsWindowSlow, JS_BeginRequest};
-use jsapi::{JS_DefineFunctions, JS_DefineProperties, JS_DestroyRuntime, JS_EndRequest};
+use jsapi::{JS_DefineFunctions, JS_DefineProperties, JS_DestroyRuntime, JS_EndRequest, JS_ShutDown};
 use jsapi::{JS_EnterCompartment, JS_EnumerateStandardClasses, JS_GetContext, JS_GlobalObjectTraceHook};
 use jsapi::{JS_Init, JS_LeaveCompartment, JS_MayResolveStandardClass, JS_NewRuntime, JS_ResolveStandardClass};
 use jsapi::{JS_SetGCParameter, JS_SetNativeStackQuota, JS_WrapValue, JSAutoCompartment};
@@ -98,6 +99,11 @@ impl ToResult for bool {
 
 thread_local!(static CONTEXT: Cell<*mut JSContext> = Cell::new(ptr::null_mut()));
 
+lazy_static! {
+    static ref OUTSTANDING_RUNTIMES: AtomicUsize = AtomicUsize::new(0);
+    static ref SHUT_DOWN: AtomicBool = AtomicBool::new(false);
+}
+
 /// A wrapper for the `JSRuntime` and `JSContext` structures in SpiderMonkey.
 pub struct Runtime {
     rt: *mut JSRuntime,
@@ -115,7 +121,13 @@ impl Runtime {
     }
 
     /// Creates a new `JSRuntime` and `JSContext`.
-    pub fn new() -> Runtime {
+    pub fn new() -> Result<Runtime, ()> {
+        if SHUT_DOWN.load(Ordering::SeqCst) {
+            return Err(());
+        }
+
+        OUTSTANDING_RUNTIMES.fetch_add(1, Ordering::SeqCst);
+
         unsafe {
             struct TopRuntime(*mut JSRuntime);
             unsafe impl Sync for TopRuntime {}
@@ -172,10 +184,10 @@ impl Runtime {
 
             JS_BeginRequest(js_context);
 
-            Runtime {
+            Ok(Runtime {
                 rt: js_runtime,
                 cx: js_context,
-            }
+            })
         }
     }
 
@@ -231,6 +243,11 @@ impl Drop for Runtime {
                 assert_eq!(context.get(), self.cx);
                 context.set(ptr::null_mut());
             });
+
+            if OUTSTANDING_RUNTIMES.fetch_sub(1, Ordering::SeqCst) == 1 {
+                SHUT_DOWN.store(true, Ordering::SeqCst);
+                JS_ShutDown();
+            }
         }
     }
 }

tests/callback.rs

@@ -25,7 +25,7 @@ use std::str;
 
 #[test]
 fn callback() {
-    let runtime = Runtime::new();
+    let runtime = Runtime::new().unwrap();
     let context = runtime.cx();
     let h_option = OnNewGlobalHookOption::FireOnNewGlobalHook;
     let c_option = CompartmentOptions::default();

tests/enumerate.rs

@@ -21,7 +21,7 @@ use std::ptr;
 
 #[test]
 fn enumerate() {
-    let rt = Runtime::new();
+    let rt = Runtime::new().unwrap();
     let cx = rt.cx();
 
     unsafe {

tests/evaluate.rs

@@ -15,7 +15,7 @@ use std::ptr;
 
 #[test]
 fn evaluate() {
-    let rt = Runtime::new();
+    let rt = Runtime::new().unwrap();
     let cx = rt.cx();
 
     unsafe {

tests/panic.rs

@@ -21,7 +21,7 @@ use std::str;
 #[test]
 #[should_panic]
 fn panic() {
-    let runtime = Runtime::new();
+    let runtime = Runtime::new().unwrap();
     let context = runtime.cx();
     let h_option = OnNewGlobalHookOption::FireOnNewGlobalHook;
     let c_option = CompartmentOptions::default();

tests/rooting.rs

@@ -28,7 +28,7 @@ use std::ptr;
 #[test]
 fn rooting() {
     unsafe {
-        let runtime = Runtime::new();
+        let runtime = Runtime::new().unwrap();
         JS_SetGCZeal(runtime.rt(), 2, 1);
 
         let cx = runtime.cx();

tests/runtime.rs

@@ -21,7 +21,7 @@ use std::ptr;
 #[test]
 fn runtime() {
     unsafe {
-        let runtime = Runtime::new();
+        let runtime = Runtime::new().unwrap();
 
         let cx = runtime.cx();
         let h_option = OnNewGlobalHookOption::FireOnNewGlobalHook;
@@ -35,6 +35,8 @@ fn runtime() {
         let _ac = JSAutoCompartment::new(cx, global.get());
         rooted!(in(cx) let _object = JS_NewObject(cx, &CLASS as *const _));
     }
+
+    assert!(Runtime::new().is_err());
 }
 
 unsafe extern fn finalize(_fop: *mut JSFreeOp, _object: *mut JSObject) {

tests/stack_limit.rs

@@ -15,7 +15,7 @@ use std::ptr;
 
 #[test]
 fn stack_limit() {
-    let rt = Runtime::new();
+    let rt = Runtime::new().unwrap();
     let cx = rt.cx();
 
     unsafe {

tests/typedarray.rs

@@ -18,7 +18,7 @@ use std::ptr;
 
 #[test]
 fn typedarray() {
-    let rt = Runtime_::new();
+    let rt = Runtime_::new().unwrap();
     let cx = rt.cx();
 
     unsafe {
@@ -76,7 +76,7 @@ fn typedarray() {
 #[test]
 #[should_panic]
 fn typedarray_update_panic() {
-    let rt = Runtime_::new();
+    let rt = Runtime_::new().unwrap();
     let cx = rt.cx();
 
     unsafe {

tests/vec_conversion.rs

@@ -21,7 +21,7 @@ use std::ptr;
 
 #[test]
 fn vec_conversion() {
-    let rt = Runtime::new();
+    let rt = Runtime::new().unwrap();
     let cx = rt.cx();
 
     let h_option = OnNewGlobalHookOption::FireOnNewGlobalHook;