ircd::js: GC related fixes.

include/ircd/js/context.h

@@ -128,7 +128,7 @@ void set(context &c, const JSGCParamKey &, const uint32_t &val);
 uint32_t get(context &c, const JSGCParamKey &);
 void out_of_memory(context &c);
 void allocation_overflow(context &c);
-void run_gc(context &c);
+bool run_gc(context &c) noexcept;
 
 // Exception
 bool pending_exception(const context &c);

include/ircd/js/global.h

@@ -26,7 +26,7 @@ namespace ircd {
 namespace js   {
 
 struct global
-:heap_object
+:persist_object
 {
 	global(trap &, JSPrincipals *const & = nullptr);
 };

include/ircd/js/object.h

@@ -97,6 +97,7 @@ struct object
 
 using object = basic::object<lifetime::stack>;
 using heap_object = basic::object<lifetime::heap>;
+using persist_object = basic::object<lifetime::persist>;
 
 //
 // Implementation

include/ircd/js/runtime.h

@@ -92,15 +92,9 @@ runtime &our_runtime(JSFreeOp &);
 
 // Do not call interrupt() unless you know what you're doing; see context.h.
 void interrupt(runtime &r);
-void run_gc(runtime &r);
+bool run_gc(runtime &r) noexcept;
 
 
-inline void
-run_gc(runtime &r)
-{
-	JS_GC(r);
-}
-
 inline void
 interrupt(runtime &r)
 {

include/ircd/js/trap.h

@@ -44,6 +44,7 @@ class trap
 	virtual bool on_has(object::handle, id::handle);
 	virtual void on_enu(object::handle);
 	virtual void on_new(object::handle, object &, const args &);
+	virtual void on_trace(const JSObject &);
 	virtual void on_gc(JSObject &);
 
   private:

include/ircd/js/value.h

@@ -189,7 +189,8 @@ value<L>::value(const std::string &s)
 :value<L>::root::type{[&s]
 {
 	auto buf(native_external_copy(s));
-	const auto ret(JS_NewExternalString(*cx, buf.release(), s.size(), &native_external_delete));
+	const auto ret(JS_NewExternalString(*cx, buf.get(), s.size(), &native_external_delete));
+	buf.release();
 	return JS::StringValue(ret);
 }()}
 {
@@ -201,7 +202,8 @@ value<L>::value(const char *const &s)
 {
 	const auto len(strlen(s));
 	auto buf(native_external_copy(s, len));
-	const auto ret(JS_NewExternalString(*cx, buf.release(), len, &native_external_delete));
+	const auto ret(JS_NewExternalString(*cx, buf.get(), len, &native_external_delete));
+	buf.release();
 	return JS::StringValue(ret);
 }()}
 {

ircd/js.cc

@@ -274,6 +274,7 @@ catch(const std::exception &e)
 ircd::js::task::~task()
 noexcept
 {
+	run_gc(*rt);
 	tasks_remove();
 }
 
@@ -371,7 +372,7 @@ ircd::js::task::tasks_next_pid()
 
 ircd::js::global::global(trap &trap,
                          JSPrincipals *const &principals)
-:heap_object
+:persist_object
 {
 	JS_NewGlobalObject(*cx, &trap.jsclass(), principals, JS::DontFireOnNewGlobalHook)
 }
@@ -542,10 +543,6 @@ noexcept
 	//_class->trace = nullptr;
 	memset(_class.get(), 0x0, sizeof(JSClass));
 	class_drain.emplace_front(std::move(_class));
-
-	// Must run GC here to force reclamation of objects before
-	// the JSClass hosted by this trap destructs.
-	//run_gc(*rt);
 }
 
 void
@@ -973,8 +970,13 @@ ircd::js::trap::handle_trace(JSTracer *const tracer,
                              JSObject *const obj)
 noexcept try
 {
+	assert(cx);
+	assert(tracer);
+	assert(obj);
+
 	auto &trap(from(*obj));
 	trap.debug("trace");
+	trap.on_trace(*obj);
 }
 catch(const jserror &e)
 {
@@ -2548,10 +2550,17 @@ ircd::js::save_exception(context &c,
 	c.report = report;
 }
 
-void
+bool
 ircd::js::run_gc(context &c)
+noexcept
 {
+	// JS_MaybeGC dereferences the context's current zone without checking if the context
+	// is even in a compartment/has a current zone; we must check here.
+	if(!current_zone(c))
+		return false;
+
 	JS_MaybeGC(c);
+	return true;
 }
 
 void
@@ -2808,6 +2817,14 @@ noexcept
 {
 }
 
+bool
+ircd::js::run_gc(runtime &r)
+noexcept
+{
+	JS_GC(r);
+	return true;
+}
+
 bool
 ircd::js::runtime::handle_interrupt(JSContext *const ctx)
 noexcept