diff options
Diffstat (limited to 'components/script/dom')
| -rw-r--r-- | components/script/dom/window.rs | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs index 7dd8d71e9c8..37bf817ed7a 100644 --- a/components/script/dom/window.rs +++ b/components/script/dom/window.rs @@ -901,18 +901,24 @@ impl Window { } pub fn clear_js_runtime(&self) { + // We tear down the active document, which causes all the attached + // nodes to dispose of their layout data. This messages the layout + // thread, informing it that it can safely free the memory. self.Document().upcast::<Node>().teardown(); - // The above code may not catch all DOM objects - // (e.g. DOM objects removed from the tree that haven't - // been collected yet). Forcing a GC here means that - // those DOM objects will be able to call dispose() - // to free their layout data before the layout thread - // exits. Without this, those remaining objects try to - // send a message to free their layout data to the - // layout thread when the script thread is dropped, - // which causes a panic! + // The above code may not catch all DOM objects (e.g. DOM + // objects removed from the tree that haven't been collected + // yet). There should not be any such DOM nodes with layout + // data, but if there are, then when they are dropped, they + // will attempt to send a message to the closed layout thread. + // This causes memory safety issues, because the DOM node uses + // the layout channel from its window, and the window has + // already been GC'd. For nodes which do not have a live + // pointer, we can avoid this by GCing now: self.Gc(); + // but there may still be nodes being kept alive by user + // script. + // TODO: ensure that this doesn't happen! self.current_state.set(WindowState::Zombie); *self.js_runtime.borrow_mut() = None; @@ -1445,6 +1451,15 @@ impl Window { None } + pub fn freeze(&self) { + self.upcast::<GlobalScope>().suspend(); + // A hint to the JS runtime that now would be a good time to + // GC any unreachable objects generated by user script, + // or unattached DOM nodes. Attached DOM nodes can't be GCd yet, + // as the document might be thawed later. + self.Gc(); + } + pub fn thaw(&self) { self.upcast::<GlobalScope>().resume(); |