diff options
| -rw-r--r-- | components/style/properties/gecko.mako.rs | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs index f1451c3190b..3037f78cd98 100644 --- a/components/style/properties/gecko.mako.rs +++ b/components/style/properties/gecko.mako.rs @@ -36,6 +36,8 @@ use properties::CascadePropertyFn; use properties::longhands; use std::fmt::{self, Debug}; use std::mem::{transmute, uninitialized, zeroed}; +use std::ptr; +use std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize, Ordering}; use std::sync::Arc; use std::cmp; @@ -102,14 +104,14 @@ impl ComputedValues { pub fn initial_values() -> &'static Self { unsafe { - debug_assert!(!INITIAL_GECKO_VALUES.is_null()); - &*INITIAL_GECKO_VALUES + debug_assert!(!raw_initial_values().is_null()); + &*raw_initial_values() } } pub unsafe fn initialize() { - debug_assert!(INITIAL_GECKO_VALUES.is_null()); - INITIAL_GECKO_VALUES = Box::into_raw(Box::new(ComputedValues { + debug_assert!(raw_initial_values().is_null()); + set_raw_initial_values(Box::into_raw(Box::new(ComputedValues { % for style_struct in data.style_structs: ${style_struct.ident}: style_structs::${style_struct.name}::initial(), % endfor @@ -117,12 +119,13 @@ impl ComputedValues { shareable: true, writing_mode: WritingMode::empty(), root_font_size: longhands::font_size::get_initial_value(), - })); + }))); } pub unsafe fn shutdown() { - debug_assert!(!INITIAL_GECKO_VALUES.is_null()); - let _ = Box::from_raw(INITIAL_GECKO_VALUES); + debug_assert!(!raw_initial_values().is_null()); + let _ = Box::from_raw(raw_initial_values()); + set_raw_initial_values(ptr::null_mut()); } #[inline] @@ -1362,7 +1365,16 @@ ${impl_style_struct(style_struct)} ${define_ffi_struct_accessor(style_struct)} % endfor -static mut INITIAL_GECKO_VALUES: *mut ComputedValues = 0 as *mut ComputedValues; +// To avoid UB, we store the initial values as a atomic. It would be nice to +// store them as AtomicPtr, but we can't have static AtomicPtr without const +// fns, which aren't in stable Rust. +static INITIAL_VALUES_STORAGE: AtomicUsize = ATOMIC_USIZE_INIT; +unsafe fn raw_initial_values() -> *mut ComputedValues { + INITIAL_VALUES_STORAGE.load(Ordering::Relaxed) as *mut ComputedValues +} +unsafe fn set_raw_initial_values(v: *mut ComputedValues) { + INITIAL_VALUES_STORAGE.store(v as usize, Ordering::Relaxed); +} static CASCADE_PROPERTY: [CascadePropertyFn; ${len(data.longhands)}] = [ % for property in data.longhands: |