Convert LayoutContext.image_cache from @mut to MutexArc

LocalImageCache isn't Freeze so we have to use unsafe_access,
which exists for MutexArc and not RWArc.

src/components/main/layout/box.rs

@@ -5,6 +5,7 @@
 //! The `Box` type, which represents the leaves of the layout tree.
 
 use extra::url::Url;
+use extra::arc::MutexArc;
 use geom::{Point2D, Rect, Size2D, SideOffsets2D};
 use gfx::color::rgb;
 use gfx::display_list::{BaseDisplayItem, BorderDisplayItem, BorderDisplayItemClass};
@@ -98,7 +99,7 @@ impl ImageBoxInfo {
     ///
     /// FIXME(pcwalton): The fact that image boxes store the cache in the box makes little sense to
     /// me.
-    pub fn new(image_url: Url, local_image_cache: @mut LocalImageCache) -> ImageBoxInfo {
+    pub fn new(image_url: Url, local_image_cache: MutexArc<LocalImageCache>) -> ImageBoxInfo {
         ImageBoxInfo {
             image: Slot::init(ImageHolder::new(image_url, local_image_cache)),
         }

src/components/main/layout/construct.rs

@@ -209,7 +209,7 @@ impl<'self> FlowConstructor<'self> {
             Some(url) => {
                 // FIXME(pcwalton): The fact that image boxes store the cache within them makes
                 // little sense to me.
-                Some(ImageBoxInfo::new(url, self.layout_context.image_cache))
+                Some(ImageBoxInfo::new(url, self.layout_context.image_cache.clone()))
             }
         }
     }

src/components/main/layout/context.rs

@@ -9,9 +9,11 @@ use gfx::font_context::FontContext;
 use servo_util::geometry::Au;
 use servo_net::local_image_cache::LocalImageCache;
 
+use extra::arc::MutexArc;
+
 /// Data needed by the layout task.
 pub struct LayoutContext {
     font_ctx: @mut FontContext,
-    image_cache: @mut LocalImageCache,
+    image_cache: MutexArc<LocalImageCache>,
     screen_size: Rect<Au>
 }

src/components/main/layout/layout_task.rs

@@ -18,7 +18,7 @@ use layout::flow;
 use layout::incremental::{RestyleDamage, BubbleWidths};
 use layout::util::{LayoutData, LayoutDataAccess};
 
-use extra::arc::{Arc, RWArc};
+use extra::arc::{Arc, RWArc, MutexArc};
 use geom::point::Point2D;
 use geom::rect::Rect;
 use geom::size::Size2D;
@@ -75,7 +75,7 @@ struct LayoutTask {
     image_cache_task: ImageCacheTask,
 
     /// The local image cache.
-    local_image_cache: @mut LocalImageCache,
+    local_image_cache: MutexArc<LocalImageCache>,
 
     /// The local font context.
     font_ctx: @mut FontContext,
@@ -239,7 +239,7 @@ impl LayoutTask {
             script_chan: script_chan,
             render_chan: render_chan,
             image_cache_task: image_cache_task.clone(),
-            local_image_cache: @mut LocalImageCache(image_cache_task),
+            local_image_cache: MutexArc::new(LocalImageCache(image_cache_task)),
             font_ctx: fctx,
             screen_size: None,
 
@@ -259,7 +259,7 @@ impl LayoutTask {
 
     // Create a layout context for use in building display lists, hit testing, &c.
     fn build_layout_context(&self) -> LayoutContext {
-        let image_cache = self.local_image_cache;
+        let image_cache = self.local_image_cache.clone();
         let font_ctx = self.font_ctx;
         let screen_size = self.screen_size.unwrap();
 
@@ -399,7 +399,10 @@ impl LayoutTask {
         debug!("{:?}", node.dump());
 
         // Reset the image cache.
-        self.local_image_cache.next_round(self.make_on_image_available_cb());
+        unsafe {
+            self.local_image_cache.unsafe_access(
+                |cache| cache.next_round(self.make_on_image_available_cb()));
+        }
 
         let screen_size = Size2D(Au::from_px(data.window_size.width as int),
                                  Au::from_px(data.window_size.height as int));

src/components/net/image/holder.rs

@@ -9,7 +9,7 @@ use local_image_cache::LocalImageCache;
 use std::util::replace;
 use geom::size::Size2D;
 use extra::url::Url;
-use extra::arc::Arc;
+use extra::arc::{Arc, MutexArc};
 
 // FIXME: Nasty coupling here This will be a problem if we want to factor out image handling from
 // the network stack. This should probably be factored out into an interface and use dependency
@@ -21,11 +21,11 @@ pub struct ImageHolder {
     url: Url,
     image: Option<Arc<~Image>>,
     cached_size: Size2D<int>,
-    local_image_cache: @mut LocalImageCache,
+    local_image_cache: MutexArc<LocalImageCache>,
 }
 
 impl ImageHolder {
-    pub fn new(url: Url, local_image_cache: @mut LocalImageCache) -> ImageHolder {
+    pub fn new(url: Url, local_image_cache: MutexArc<LocalImageCache>) -> ImageHolder {
         debug!("ImageHolder::new() {}", url.to_str());
         let holder = ImageHolder {
             url: url,
@@ -39,8 +39,14 @@ impl ImageHolder {
         // but they are intended to be spread out in time. Ideally prefetch
         // should be done as early as possible and decode only once we
         // are sure that the image will be used.
-        local_image_cache.prefetch(&holder.url);
-        local_image_cache.decode(&holder.url);
+        //
+        // LocalImageCache isn't Freeze so we have to use unsafe_access.
+        unsafe {
+            holder.local_image_cache.unsafe_access(|cache| {
+                cache.prefetch(&holder.url);
+                cache.decode(&holder.url);
+            });
+        }
 
         holder
     }
@@ -71,7 +77,11 @@ impl ImageHolder {
         // If this is the first time we've called this function, load
         // the image and store it for the future
         if self.image.is_none() {
-            match self.local_image_cache.get_image(&self.url).recv() {
+            let port = unsafe {
+                self.local_image_cache.unsafe_access(
+                    |cache| cache.get_image(&self.url))
+            };
+            match port.recv() {
                 ImageReady(image) => {
                     self.image = Some(image);
                 }