RequestServer+LibHTTP: Cancel requests on client exit

That usually happens in "exceptional" states when the client exits
unexpectedly (crash, force quit mid-load, etc), leading to the job flush
timer firing and attempting to write to a nonexistent object (the
client).

This commit makes RS simply cancel such jobs; cancelled jobs in this
state simply go away instead of sending notifications around.

Userland/Libraries/LibHTTP/Job.cpp

@@ -576,6 +576,13 @@ void Job::finish_up()
 {
     VERIFY(!m_has_scheduled_finish);
     m_state = State::Finished;
+
+    if (is_cancelled()) {
+        stop_timer();
+        m_has_scheduled_finish = true;
+        return;
+    }
+
     if (!m_can_stream_response) {
         auto maybe_flattened_buffer = ByteBuffer::create_uninitialized(m_buffered_size);
         if (maybe_flattened_buffer.is_error())

Userland/Services/RequestServer/ConnectionCache.h

@@ -101,7 +101,7 @@ struct JobData {
 #endif
 
     template<typename T>
-    static JobData create(NonnullRefPtr<T> job, [[maybe_unused]] URL::URL url)
+    static JobData create(WeakPtr<T> job, [[maybe_unused]] URL::URL url)
     {
         return JobData {
             [job](auto& socket) { job->start(socket); },

Userland/Services/RequestServer/ConnectionFromClient.cpp

@@ -46,6 +46,14 @@ ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> sock
     s_connections.set(client_id(), *this);
 }
 
+ConnectionFromClient::~ConnectionFromClient()
+{
+    m_requests.with_locked([](HashMap<i32, OwnPtr<Request>>& map) {
+        for (auto& entry : map)
+            entry.value->cancel();
+    });
+}
+
 class Job : public RefCounted<Job>
     , public Weakable<Job> {
 public:
@@ -152,10 +160,9 @@ void ConnectionFromClient::worker_do_work(Work work)
                 return;
             }
 
-            auto job = Job::ensure(url);
             dbgln("EnsureConnection: Pre-connect to {}", url);
-            auto do_preconnect = [&](auto& cache) {
-                ConnectionCache::ensure_connection(cache, url, job);
+            auto do_preconnect = [=, job = Job::ensure(url)](auto& cache) {
+                ConnectionCache::ensure_connection(cache, url, job->make_weak_ptr<Job>());
             };
 
             if (url.scheme() == "http"sv)

Userland/Services/RequestServer/ConnectionFromClient.h

@@ -23,7 +23,7 @@ class ConnectionFromClient final
     C_OBJECT(ConnectionFromClient);
 
 public:
-    ~ConnectionFromClient() override = default;
+    ~ConnectionFromClient() override;
 
     virtual void die() override;
 

Userland/Services/RequestServer/HttpCommon.h

@@ -99,10 +99,10 @@ OwnPtr<Request> start_request(TBadgedProtocol&& protocol, i32 request_id, Connec
 
     auto output_stream = MUST(Core::File::adopt_fd(pipe_result.value().write_fd, Core::File::OpenMode::Write));
     auto job = TJob::construct(move(request), *output_stream);
-    auto protocol_request = TRequest::create_with_job(forward<TBadgedProtocol>(protocol), client, (TJob&)*job, move(output_stream), request_id);
+    auto protocol_request = TRequest::create_with_job(forward<TBadgedProtocol>(protocol), client, static_cast<TJob&>(*job), move(output_stream), request_id);
     protocol_request->set_request_fd(pipe_result.value().read_fd);
 
-    Core::deferred_invoke([=] {
+    Core::deferred_invoke([=, job = job->template make_weak_ptr<TJob>()] {
         if constexpr (IsSame<typename TBadgedProtocol::Type, HttpsProtocol>)
             ConnectionCache::ensure_connection(ConnectionCache::g_tls_connection_cache, url, job, proxy_data);
         else

Userland/Services/RequestServer/HttpRequest.h

@@ -23,6 +23,7 @@ public:
     HTTP::Job const& job() const { return m_job; }
 
     virtual URL::URL url() const override { return m_job->url(); }
+    virtual void cancel() override { m_job->cancel(); }
 
 private:
     explicit HttpRequest(ConnectionFromClient&, NonnullRefPtr<HTTP::Job>, NonnullOwnPtr<Core::File>&&, i32);

Userland/Services/RequestServer/HttpsRequest.h

@@ -22,6 +22,7 @@ public:
     HTTP::HttpsJob const& job() const { return m_job; }
 
     virtual URL::URL url() const override { return m_job->url(); }
+    virtual void cancel() override { m_job->cancel(); }
 
 private:
     explicit HttpsRequest(ConnectionFromClient&, NonnullRefPtr<HTTP::HttpsJob>, NonnullOwnPtr<Core::File>&&, i32);

Userland/Services/RequestServer/Request.h

@@ -34,6 +34,8 @@ public:
     void set_request_fd(int fd) { m_request_fd = fd; }
     int request_fd() const { return m_request_fd; }
 
+    virtual void cancel() = 0;
+
     void did_finish(bool success);
     void did_progress(Optional<u64> total_size, u64 downloaded_size);
     void set_status_code(u32 status_code) { m_status_code = status_code; }