Auto merge of #16282 - upsuper:bug1343964, r=heycam

Move dummy url data to be a static member of URLExtraData

This is the Servo side change of [bug 1343964](https://bugzilla.mozilla.org/show_bug.cgi?id=1343964) which has been reviewed on Bugzilla.

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Cargo.lock

@@ -2787,12 +2787,10 @@ dependencies = [
  "env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "geckoservo 0.0.1",
- "lazy_static 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.18.0",
- "servo_url 0.0.1",
  "style 0.0.1",
  "style_traits 0.0.1",
 ]

components/style/gecko_bindings/bindings.rs

@@ -444,9 +444,6 @@ extern "C" {
                                 url_bytes: *const u8, url_length: u32,
                                 media_bytes: *const u8, media_length: u32);
 }
-extern "C" {
-    pub fn Gecko_URLExtraData_CreateDummy() -> *mut RawGeckoURLExtraData;
-}
 extern "C" {
     pub fn Gecko_MaybeCreateStyleChildrenIterator(node: RawGeckoNodeBorrowed)
      -> StyleChildrenIteratorOwnedOrNull;
@@ -1859,7 +1856,7 @@ extern "C" {
      -> ServoComputedValuesStrong;
 }
 extern "C" {
-    pub fn Servo_Initialize();
+    pub fn Servo_Initialize(dummy_url_data: *mut RawGeckoURLExtraData);
 }
 extern "C" {
     pub fn Servo_Shutdown();

ports/geckolib/glue.rs

@@ -100,10 +100,10 @@ use super::stylesheet_loader::StylesheetLoader;
 
 // A dummy url data for where we don't pass url data in.
 // We need to get rid of this sooner than later.
-static mut DUMMY_URL_DATA: Option<*mut URLExtraData> = None;
+static mut DUMMY_URL_DATA: *mut URLExtraData = 0 as *mut URLExtraData;
 
 #[no_mangle]
-pub extern "C" fn Servo_Initialize() {
+pub extern "C" fn Servo_Initialize(dummy_url_data: *mut URLExtraData) {
     // Initialize logging.
     let mut builder = LogBuilder::new();
     let default_level = if cfg!(debug_assertions) { "warn" } else { "error" };
@@ -122,9 +122,7 @@ pub extern "C" fn Servo_Initialize() {
     gecko_properties::initialize();
 
     // Initialize the dummy url data
-    unsafe {
-        DUMMY_URL_DATA = Some(bindings::Gecko_URLExtraData_CreateDummy());
-    }
+    unsafe { DUMMY_URL_DATA = dummy_url_data; }
 }
 
 #[no_mangle]
@@ -132,12 +130,13 @@ pub extern "C" fn Servo_Shutdown() {
     // Clear some static data to avoid shutdown leaks.
     gecko_properties::shutdown();
 
-    // Clear the dummy url data to avoid shutdown leaks.
-    unsafe { RefPtr::from_addrefed(DUMMY_URL_DATA.take().unwrap()) };
+    // The dummy url will be released after shutdown, so clear the
+    // reference to avoid use-after-free.
+    unsafe { DUMMY_URL_DATA = ptr::null_mut(); }
 }
 
 unsafe fn dummy_url_data() -> &'static RefPtr<URLExtraData> {
-    RefPtr::from_ptr_ref(DUMMY_URL_DATA.as_ref().unwrap())
+    RefPtr::from_ptr_ref(&DUMMY_URL_DATA)
 }
 
 fn create_shared_context<'a>(guard: &'a SharedRwLockReadGuard,

tests/unit/stylo/Cargo.toml

@@ -19,12 +19,10 @@ atomic_refcell = "0.1"
 cssparser = "0.12"
 env_logger = "0.4"
 euclid = "0.11"
-lazy_static = "0.2"
 libc = "0.2"
 log = {version = "0.3.5", features = ["release_max_level_info"]}
 parking_lot = "0.3"
 selectors = {path = "../../../components/selectors"}
-servo_url = {path = "../../../components/url"}
 style_traits = {path = "../../../components/style_traits"}
 geckoservo = {path = "../../../ports/geckolib"}
 style = {path = "../../../components/style", features = ["gecko"]}

tests/unit/stylo/lib.rs

@@ -6,11 +6,9 @@ extern crate atomic_refcell;
 extern crate cssparser;
 extern crate env_logger;
 extern crate geckoservo;
-#[macro_use] extern crate lazy_static;
 #[macro_use] extern crate log;
 extern crate parking_lot;
 extern crate selectors;
-extern crate servo_url;
 #[macro_use] extern crate style;
 extern crate style_traits;