net: De-GC the image cache stuff.

This is a step on the way toward parallel layout.

src/components/net/image_cache_task.rs

@@ -48,22 +48,13 @@ pub enum Msg {
     Exit(Chan<()>),
 }
 
+#[deriving(Clone)]
 pub enum ImageResponseMsg {
     ImageReady(Arc<~Image>),
     ImageNotReady,
     ImageFailed
 }
 
-impl ImageResponseMsg {
-    fn clone(&self) -> ImageResponseMsg {
-        match *self {
-            ImageReady(ref img) => ImageReady(img.clone()),
-            ImageNotReady => ImageNotReady,
-            ImageFailed => ImageFailed,
-        }
-    }
-}
-
 impl Eq for ImageResponseMsg {
     fn eq(&self, other: &ImageResponseMsg) -> bool {
         // FIXME: Bad copies
@@ -243,11 +234,11 @@ impl ImageCache {
         }
     }
 
-    fn set_state(&self, url: Url, state: ImageState) {
+    fn set_state(&mut self, url: Url, state: ImageState) {
         self.state_map.insert(url, state);
     }
 
-    fn prefetch(&self, url: Url) {
+    fn prefetch(&mut self, url: Url) {
         match self.get_state(url.clone()) {
             Init => {
                 let to_cache = self.chan.clone();
@@ -278,7 +269,7 @@ impl ImageCache {
         }
     }
 
-    fn store_prefetched_image_data(&self, url: Url, data: Result<Cell<~[u8]>, ()>) {
+    fn store_prefetched_image_data(&mut self, url: Url, data: Result<Cell<~[u8]>, ()>) {
         match self.get_state(url.clone()) {
           Prefetching(next_step) => {
             match data {
@@ -307,7 +298,7 @@ impl ImageCache {
         }
     }
 
-    fn decode(&self, url: Url) {
+    fn decode(&mut self, url: Url) {
         match self.get_state(url.clone()) {
             Init => fail!(~"decoding image before prefetch"),
 
@@ -350,7 +341,7 @@ impl ImageCache {
         }
     }
 
-    fn store_image(&self, url: Url, image: Option<Arc<~Image>>) {
+    fn store_image(&mut self, url: Url, image: Option<Arc<~Image>>) {
 
         match self.get_state(url.clone()) {
           Decoding => {
@@ -377,7 +368,7 @@ impl ImageCache {
 
     }
 
-    fn purge_waiters(&self, url: Url, f: &fn() -> ImageResponseMsg) {
+    fn purge_waiters(&mut self, url: Url, f: &fn() -> ImageResponseMsg) {
         match self.wait_map.pop(&url) {
             Some(waiters) => {
                 for response in waiters.iter() {
@@ -399,7 +390,7 @@ impl ImageCache {
         }
     }
 
-    fn wait_for_image(&self, url: Url, response: Chan<ImageResponseMsg>) {
+    fn wait_for_image(&mut self, url: Url, response: Chan<ImageResponseMsg>) {
         match self.get_state(url.clone()) {
             Init => fail!(~"request for image before prefetch"),
 

src/components/net/local_image_cache.rs

@@ -34,9 +34,10 @@ pub struct LocalImageCache {
     priv image_cache_task: ImageCacheTask,
     priv round_number: uint,
     priv on_image_available: Option<~ImageResponder:Send>,
-    priv state_map: UrlMap<@mut ImageState>
+    priv state_map: UrlMap<ImageState>
 }
 
+#[deriving(Clone)]
 struct ImageState {
     prefetched: bool,
     decoded: bool,
@@ -52,51 +53,62 @@ impl LocalImageCache {
         self.on_image_available = Some(on_image_available);
     }
 
-    pub fn prefetch(&self, url: &Url) {
-        let state = self.get_state(url);
-        if !state.prefetched {
-            self.image_cache_task.send(Prefetch((*url).clone()));
+    pub fn prefetch(&mut self, url: &Url) {
+        {
+            let state = self.get_state(url);
+            if state.prefetched {
+                return
+            }
+
             state.prefetched = true;
         }
+
+        self.image_cache_task.send(Prefetch((*url).clone()));
     }
 
-    pub fn decode(&self, url: &Url) {
-        let state = self.get_state(url);
-        if !state.decoded {
-            self.image_cache_task.send(Decode((*url).clone()));
+    pub fn decode(&mut self, url: &Url) {
+        {
+            let state = self.get_state(url);
+            if state.decoded {
+                return
+            }
             state.decoded = true;
         }
+
+        self.image_cache_task.send(Decode((*url).clone()));
     }
 
     // FIXME: Should return a Future
-    pub fn get_image(&self, url: &Url) -> Port<ImageResponseMsg> {
-        let state = self.get_state(url);
+    pub fn get_image(&mut self, url: &Url) -> Port<ImageResponseMsg> {
+        {
+            let state = self.get_state(url);
 
-        // Save the previous round number for comparison
-        let last_round = state.last_request_round;
-        // Set the current round number for this image
-        state.last_request_round = self.round_number;
+            // Save the previous round number for comparison
+            let last_round = state.last_request_round;
+            // Set the current round number for this image
+            state.last_request_round = self.round_number;
 
-        match state.last_response {
-            ImageReady(ref image) => {
-                let (port, chan) = comm::stream();
-                chan.send(ImageReady(image.clone()));
-                return port;
-            }
-            ImageNotReady => {
-                if last_round == self.round_number {
+            match state.last_response {
+                ImageReady(ref image) => {
                     let (port, chan) = comm::stream();
-                    chan.send(ImageNotReady);
+                    chan.send(ImageReady(image.clone()));
+                    return port;
+                }
+                ImageNotReady => {
+                    if last_round == self.round_number {
+                        let (port, chan) = comm::stream();
+                        chan.send(ImageNotReady);
+                        return port;
+                    } else {
+                        // We haven't requested the image from the
+                        // remote cache this round
+                    }
+                }
+                ImageFailed => {
+                    let (port, chan) = comm::stream();
+                    chan.send(ImageFailed);
                     return port;
-                } else {
-                    // We haven't requested the image from the
-                    // remote cache this round
                 }
-            }
-            ImageFailed => {
-                let (port, chan) = comm::stream();
-                chan.send(ImageFailed);
-                return port;
             }
         }
 
@@ -130,24 +142,24 @@ impl LocalImageCache {
             ImageNotReady => ImageNotReady,
             ImageFailed => ImageFailed
         };
-        state.last_response = response_copy;
+        self.get_state(url).last_response = response_copy;
 
         let (port, chan) = comm::stream();
         chan.send(response);
         return port;
     }
 
-    fn get_state(&self, url: &Url) -> @mut ImageState {
-        let state = do self.state_map.find_or_insert_with(url.clone()) |_| {
-            let new_state = @mut ImageState {
+    fn get_state<'a>(&'a mut self, url: &Url) -> &'a mut ImageState {
+        let state = self.state_map.find_or_insert_with(url.clone(), |_| {
+            let new_state = ImageState {
                 prefetched: false,
                 decoded: false,
                 last_request_round: 0,
                 last_response: ImageNotReady
             };
             new_state
-        };
-        *state  // Unborrowing the state
+        });
+        state
     }
 }
 

src/components/util/url.rs

@@ -147,8 +147,9 @@ mod make_url_tests {
 
 }
 
-pub type UrlMap<T> = @mut HashMap<Url, T>;
+pub type UrlMap<T> = HashMap<Url, T>;
 
 pub fn url_map<T: Clone + 'static>() -> UrlMap<T> {
-    @mut HashMap::new()
+    HashMap::new()
 }
+