Fetch cancellation: Add CancellationListener

components/net/fetch/methods.rs

@@ -28,7 +28,7 @@ use std::fs::File;
 use std::io::Read;
 use std::mem;
 use std::str;
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::sync::mpsc::{Sender, Receiver};
 use subresource_integrity::is_response_integrity_valid;
 
@@ -44,9 +44,37 @@ pub struct FetchContext {
     pub user_agent: Cow<'static, str>,
     pub devtools_chan: Option<Sender<DevtoolsControlMsg>>,
     pub filemanager: FileManager,
-    pub cancel_chan: Option<IpcReceiver<()>>,
+    pub cancellation_listener: Arc<Mutex<CancellationListener>>,
 }
 
+pub struct CancellationListener {
+    cancel_chan: Option<IpcReceiver<()>>,
+    cancelled: bool,
+}
+
+impl CancellationListener {
+    pub fn new(cancel_chan: Option<IpcReceiver<()>>) -> Self {
+        Self {
+            cancel_chan: cancel_chan,
+            cancelled: false,
+        }
+    }
+
+    pub fn cancelled(&mut self) -> bool {
+        if let Some(ref cancel_chan) = self.cancel_chan {
+            if self.cancelled {
+                true
+            } else if cancel_chan.try_recv().is_ok() {
+                self.cancelled = true;
+                true
+            } else {
+                false
+            }
+        } else {
+            false
+        }
+    }
+}
 pub type DoneChannel = Option<(Sender<Data>, Receiver<Data>)>;
 
 /// [Fetch](https://fetch.spec.whatwg.org#concept-fetch)

components/net/resource_thread.rs

@@ -9,7 +9,7 @@ use cookie_rs;
 use cookie_storage::CookieStorage;
 use devtools_traits::DevtoolsControlMsg;
 use fetch::cors_cache::CorsCache;
-use fetch::methods::{FetchContext, fetch};
+use fetch::methods::{CancellationListener, FetchContext, fetch};
 use filemanager_thread::{FileManager, TFDProvider};
 use hsts::HstsList;
 use http_loader::{HttpState, http_redirect_fetch};
@@ -35,7 +35,7 @@ use std::fs::File;
 use std::io::prelude::*;
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
-use std::sync::{Arc, RwLock};
+use std::sync::{Arc, Mutex, RwLock};
 use std::sync::mpsc::Sender;
 use std::thread;
 use storage_thread::StorageThreadFactory;
@@ -347,7 +347,7 @@ impl CoreResourceManager {
                 user_agent: ua,
                 devtools_chan: dc,
                 filemanager: filemanager,
-                cancel_chan: cancel_chan,
+                cancellation_listener: Arc::new(Mutex::new(CancellationListener::new(cancel_chan))),
             };
 
             match res_init_ {