1 files changed, 24 insertions, 5 deletions
diff --git a/components/net_traits/image_cache_task.rs b/components/net_traits/image_cache_task.rs
index dd6bb3c98ff..3614cf4d58a 100644
--- a/components/net_traits/image_cache_task.rs
+++ b/components/net_traits/image_cache_task.rs
@@ -12,7 +12,7 @@ use std::sync::mpsc::{channel, Sender};
 /// image load completes. It is typically used to trigger a reflow
 /// and/or repaint.
 pub trait ImageResponder : Send {
-    fn respond(&self, Option<Arc<Image>>);
+    fn respond(&self, ImageResponse);
 }
 
 /// The current state of an image in the cache.
@@ -23,6 +23,17 @@ pub enum ImageState {
     NotRequested,
 }
 
+/// The returned image.
+#[derive(Clone)]
+pub enum ImageResponse {
+    /// The requested image was loaded.
+    Loaded(Arc<Image>),
+    /// The requested image failed to load, so a placeholder was loaded instead.
+    PlaceholderLoaded(Arc<Image>),
+    /// Neither the requested image nor the placeholder could be loaded.
+    None
+}
+
 /// Channel for sending commands to the image cache.
 #[derive(Clone)]
 pub struct ImageCacheChan(pub Sender<ImageCacheResult>);
@@ -31,7 +42,7 @@ pub struct ImageCacheChan(pub Sender<ImageCacheResult>);
 /// caller.
 pub struct ImageCacheResult {
     pub responder: Option<Box<ImageResponder>>,
-    pub image: Option<Arc<Image>>,
+    pub image_response: ImageResponse,
 }
 
 /// Commands that the image cache understands.
@@ -45,12 +56,18 @@ pub enum ImageCacheCommand {
     /// TODO(gw): Profile this on some real world sites and see
     /// if it's worth caching the results of this locally in each
     /// layout / paint task.
-    GetImageIfAvailable(Url, Sender<Result<Arc<Image>, ImageState>>),
+    GetImageIfAvailable(Url, UsePlaceholder, Sender<Result<Arc<Image>, ImageState>>),
 
     /// Clients must wait for a response before shutting down the ResourceTask
     Exit(Sender<()>),
 }
 
+#[derive(Copy, Clone, PartialEq)]
+pub enum UsePlaceholder {
+    No,
+    Yes,
+}
+
 /// The client side of the image cache task. This can be safely cloned
 /// and passed to different tasks.
 #[derive(Clone)]
@@ -78,9 +95,10 @@ impl ImageCacheTask {
     }
 
     /// Get the current state of an image. See ImageCacheCommand::GetImageIfAvailable.
-    pub fn get_image_if_available(&self, url: Url) -> Result<Arc<Image>, ImageState> {
+    pub fn get_image_if_available(&self, url: Url, use_placeholder: UsePlaceholder)
+                                  -> Result<Arc<Image>, ImageState> {
         let (sender, receiver) = channel();
-        let msg = ImageCacheCommand::GetImageIfAvailable(url, sender);
+        let msg = ImageCacheCommand::GetImageIfAvailable(url, use_placeholder, sender);
         self.chan.send(msg).unwrap();
         receiver.recv().unwrap()
     }
@@ -92,3 +110,4 @@ impl ImageCacheTask {
         response_port.recv().unwrap();
     }
 }
+