From df9da705f5b211a8814b15414bea4646b2705c8c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Thu, 29 Dec 2016 18:33:47 +0100
Subject: [PATCH] Bug 1304792: Use borrowed types for ServoImportRule.
 r=Manishearth r=heycam
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MozReview-Commit-ID: HKjsOaE2qAp
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
---
 components/style/gecko_bindings/bindings.rs        | 2 +-
 components/style/gecko_bindings/sugar/ownership.rs | 6 ++++++
 ports/geckolib/stylesheet_loader.rs                | 4 ++--
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index 389df0e845f..77a2fb2712d 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -330,7 +330,7 @@ extern "C" {
 extern "C" {
     pub fn Gecko_LoadStyleSheet(loader: *mut Loader,
                                 parent: *mut ServoStyleSheet,
-                                import_rule: RawServoImportRuleStrong,
+                                import_rule: RawServoImportRuleBorrowed,
                                 url_bytes: *const u8, url_length: u32,
                                 media_bytes: *const u8, media_length: u32);
 }
diff --git a/components/style/gecko_bindings/sugar/ownership.rs b/components/style/gecko_bindings/sugar/ownership.rs
index 13562011fbb..edd8394f31c 100644
--- a/components/style/gecko_bindings/sugar/ownership.rs
+++ b/components/style/gecko_bindings/sugar/ownership.rs
@@ -109,6 +109,12 @@ pub unsafe trait HasArcFFI : HasFFI {
         }
     }
 
+    fn arc_as_borrowed<'a>(arc: &'a Arc<Self>) -> &'a &Self::FFIType {
+        unsafe {
+            transmute::<&Arc<Self>, &&Self::FFIType>(arc)
+        }
+    }
+
     #[inline]
     fn arc_from_borrowed<'a>(ptr: &'a Option<&Self::FFIType>) -> Option<&'a Arc<Self>> {
         unsafe {
diff --git a/ports/geckolib/stylesheet_loader.rs b/ports/geckolib/stylesheet_loader.rs
index a48559d6857..3e6fb421c86 100644
--- a/ports/geckolib/stylesheet_loader.rs
+++ b/ports/geckolib/stylesheet_loader.rs
@@ -3,10 +3,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use parking_lot::RwLock;
-use std::mem;
 use std::sync::Arc;
 use style::gecko_bindings::bindings::Gecko_LoadStyleSheet;
 use style::gecko_bindings::structs::{Loader, ServoStyleSheet};
+use style::gecko_bindings::sugar::ownership::HasArcFFI;
 use style::stylesheets::{ImportRule, StylesheetLoader as StyleStylesheetLoader};
 use style_traits::ToCss;
 
@@ -37,7 +37,7 @@ impl StyleStylesheetLoader for StylesheetLoader {
         unsafe {
             Gecko_LoadStyleSheet(self.0,
                                  self.1,
-                                 mem::transmute(import_rule.clone()),
+                                 HasArcFFI::arc_as_borrowed(import_rule),
                                  spec_bytes,
                                  spec_len as u32,
                                  media.as_bytes().as_ptr(),