From 6dd7af2bdaa45f1f6fa70447f832db90a4aa35e2 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Fri, 17 Nov 2017 14:57:07 -0800
Subject: [PATCH] Fetch cancellation: Add CancellationListener

---
 components/net/fetch/methods.rs   | 32 +++++++++++++++++++++++++++++--
 components/net/resource_thread.rs |  6 +++---
 tests/unit/net/fetch.rs           |  4 ++--
 tests/unit/net/lib.rs             |  6 +++---
 4 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/components/net/fetch/methods.rs b/components/net/fetch/methods.rs
index 789501fa3223..f65c6c196f2e 100644
--- a/components/net/fetch/methods.rs
+++ b/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)
diff --git a/components/net/resource_thread.rs b/components/net/resource_thread.rs
index 8837ae64bf80..4e9a691751f3 100644
--- a/components/net/resource_thread.rs
+++ b/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_ {
diff --git a/tests/unit/net/fetch.rs b/tests/unit/net/fetch.rs
index 3508942dac33..7d3a85de763f 100644
--- a/tests/unit/net/fetch.rs
+++ b/tests/unit/net/fetch.rs
@@ -25,7 +25,7 @@ use hyper_openssl;
 use msg::constellation_msg::TEST_PIPELINE_ID;
 use net::connector::create_ssl_client;
 use net::fetch::cors_cache::CorsCache;
-use net::fetch::methods::FetchContext;
+use net::fetch::methods::{CancellationListener, FetchContext};
 use net::filemanager_thread::FileManager;
 use net::hsts::HstsEntry;
 use net::test::HttpState;
@@ -538,7 +538,7 @@ fn test_fetch_with_hsts() {
         user_agent: DEFAULT_USER_AGENT.into(),
         devtools_chan: None,
         filemanager: FileManager::new(),
-        cancel_chan: None,
+        cancellation_listener: Arc::new(Mutex::new(CancellationListener::new(None))),
     };
 
     {
diff --git a/tests/unit/net/lib.rs b/tests/unit/net/lib.rs
index bb5aed81fb32..497db8f6b302 100644
--- a/tests/unit/net/lib.rs
+++ b/tests/unit/net/lib.rs
@@ -36,7 +36,7 @@ use devtools_traits::DevtoolsControlMsg;
 use hyper::server::{Handler, Listening, Server};
 use net::connector::create_ssl_client;
 use net::fetch::cors_cache::CorsCache;
-use net::fetch::methods::{self, FetchContext};
+use net::fetch::methods::{self, CancellationListener, FetchContext};
 use net::filemanager_thread::FileManager;
 use net::test::HttpState;
 use net_traits::FetchTaskTarget;
@@ -44,7 +44,7 @@ use net_traits::request::Request;
 use net_traits::response::Response;
 use servo_config::resource_files::resources_dir_path;
 use servo_url::ServoUrl;
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::sync::mpsc::{Sender, channel};
 
 const DEFAULT_USER_AGENT: &'static str = "Such Browser. Very Layout. Wow.";
@@ -61,7 +61,7 @@ fn new_fetch_context(dc: Option<Sender<DevtoolsControlMsg>>) -> FetchContext {
         user_agent: DEFAULT_USER_AGENT.into(),
         devtools_chan: dc,
         filemanager: FileManager::new(),
-        cancel_chan: None,
+        cancellation_listener: Arc::new(Mutex::new(CancellationListener::new(None))),
     }
 }
 impl FetchTaskTarget for FetchResponseCollector {