Don't start a second pre-render if one is in progress.

components/offline_pages/background/request_coordinator_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/offline_pages/background/request_coordinator.h"
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/location.h"
+#include "base/logging.h"
 #include "base/test/test_simple_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/offline_pages/background/device_conditions.h"
 #include "components/offline_pages/background/offliner.h"
 #include "components/offline_pages/background/offliner_factory.h"
 #include "components/offline_pages/background/offliner_policy.h"
 #include "components/offline_pages/background/request_queue.h"
 #include "components/offline_pages/background/request_queue_in_memory_store.h"
 #include "components/offline_pages/background/save_page_request.h"
 #include "components/offline_pages/background/scheduler.h"
@@ skipping 24 matching lines @@
   bool schedule_called() const { return schedule_called_; }
 
   bool unschedule_called() const { return unschedule_called_; }
 
  private:
   bool schedule_called_;
   bool unschedule_called_;
 };
 
 class OfflinerStub : public Offliner {
+ public:
+  OfflinerStub() : skip_callback_(false) {}
+
   bool LoadAndSave(const SavePageRequest& request,
                    const CompletionCallback& callback) override {
     // Post the callback on the run loop.
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::Bind(callback, request, Offliner::RequestStatus::SAVED));
+    if (!skip_callback_) {
+      base::ThreadTaskRunnerHandle::Get()->PostTask(
+          FROM_HERE,
+          base::Bind(callback, request, Offliner::RequestStatus::SAVED));
+    }
     return true;
   }
 
   // Clears the currently processing request, if any.
   void Cancel() override {}
+
+  void set_skip_callback(bool skip) {
+    skip_callback_ = skip;
+  }
+
+ private:
+  bool skip_callback_;
 };
 
 class OfflinerFactoryStub : public OfflinerFactory {
  public:
   Offliner* GetOffliner(const OfflinerPolicy* policy) override {
-    offliner_.reset(new OfflinerStub());
+    if (offliner_.get() == nullptr) {
+      offliner_.reset(new OfflinerStub());
+    }
     return offliner_.get();
   }
 
  private:
   std::unique_ptr<Offliner> offliner_;
 };
 
 class RequestCoordinatorTest
     : public testing::Test {
  public:
   RequestCoordinatorTest();
   ~RequestCoordinatorTest() override;
 
   void SetUp() override;
 
   void PumpLoop();
 
   RequestCoordinator* coordinator() {
     return coordinator_.get();
   }
 
+  bool is_busy() {
+    return coordinator_->is_busy();
+  }
+
+  void SendRequestToOffliner(SavePageRequest& request) {
+    coordinator_->SendRequestToOffliner(request);
+  }
+
   // Empty callback function
   void EmptyCallbackFunction(bool result) {
   }
 
   // Callback for Add requests
   void AddRequestDone(RequestQueue::AddRequestResult result,
                       const SavePageRequest& request);
 
   // Callback for getting requests.
   void GetRequestsDone(RequestQueue::GetRequestsResult result,
                        const std::vector<SavePageRequest>& requests);
 
   void SendOfflinerDoneCallback(const SavePageRequest& request,
                                 Offliner::RequestStatus status);
 
   RequestQueue::GetRequestsResult last_get_requests_result() const {
     return last_get_requests_result_;
   }
 
   const std::vector<SavePageRequest>& last_requests() const {
     return last_requests_;
   }
 
+  void skip_offliner_callback() {
+    offliner_->set_skip_callback(true);
+  }
+
  private:
   RequestQueue::GetRequestsResult last_get_requests_result_;
   std::vector<SavePageRequest> last_requests_;
   scoped_refptr<base::TestSimpleTaskRunner> task_runner_;
   base::ThreadTaskRunnerHandle task_runner_handle_;
   std::unique_ptr<RequestCoordinator> coordinator_;
+  OfflinerStub* offliner_;
 };
 
 RequestCoordinatorTest::RequestCoordinatorTest()
     : last_get_requests_result_(RequestQueue::GetRequestsResult::STORE_FAILURE),
       task_runner_(new base::TestSimpleTaskRunner),
-      task_runner_handle_(task_runner_) {}
+      task_runner_handle_(task_runner_),
+      offliner_(nullptr) {}
 
 RequestCoordinatorTest::~RequestCoordinatorTest() {}
 
 void RequestCoordinatorTest::SetUp() {
   std::unique_ptr<OfflinerPolicy> policy(new OfflinerPolicy());
   std::unique_ptr<OfflinerFactory> factory(new OfflinerFactoryStub());
+  offliner_ =
+      reinterpret_cast<OfflinerStub*>(factory->GetOffliner(policy.get()));
   std::unique_ptr<RequestQueueInMemoryStore>
       store(new RequestQueueInMemoryStore());
   std::unique_ptr<RequestQueue> queue(new RequestQueue(std::move(store)));
   std::unique_ptr<Scheduler> scheduler_stub(new SchedulerStub());
   coordinator_.reset(new RequestCoordinator(
       std::move(policy), std::move(factory), std::move(queue),
       std::move(scheduler_stub)));
 }
 
 void RequestCoordinatorTest::PumpLoop() {
@@ skipping 22 matching lines @@
 TEST_F(RequestCoordinatorTest, StartProcessingWithNoRequests) {
   DeviceConditions device_conditions(false, 75,
                                      net::NetworkChangeNotifier::CONNECTION_3G);
   base::Callback<void(bool)> callback =
       base::Bind(
           &RequestCoordinatorTest::EmptyCallbackFunction,
           base::Unretained(this));
   EXPECT_TRUE(coordinator()->StartProcessing(device_conditions, callback));
 }
 
+TEST_F(RequestCoordinatorTest, StartProcessingWithRequestInProgress) {
+  // Put the request on the queue.
+  EXPECT_TRUE(coordinator()->SavePageLater(kUrl, kClientId));
+
+  // Set up for the call to StartProcessing by building arguments.
+  DeviceConditions device_conditions(false, 75,
+                                     net::NetworkChangeNotifier::CONNECTION_3G);
+  base::Callback<void(bool)> callback =
+      base::Bind(&RequestCoordinatorTest::EmptyCallbackFunction,
+                 base::Unretained(this));
+
+  // Ensure that the forthcoming request does not finish - we simulate it being
+  // in progress by asking it to skip making the completion callback.
+  skip_offliner_callback();
+
+  // Sending the request to the offliner should make it busy.
+  EXPECT_TRUE(coordinator()->StartProcessing(device_conditions, callback));
+  PumpLoop();
+  EXPECT_TRUE(is_busy());
+
+  // Now trying to start processing on another request should return false.
+  EXPECT_FALSE(coordinator()->StartProcessing(device_conditions, callback));
+}
+
 TEST_F(RequestCoordinatorTest, SavePageLater) {
   EXPECT_TRUE(coordinator()->SavePageLater(kUrl, kClientId));
 
   // Expect that a request got placed on the queue.
   coordinator()->queue()->GetRequests(
       base::Bind(&RequestCoordinatorTest::GetRequestsDone,
                  base::Unretained(this)));
 
   // Wait for callbacks to finish, both request queue and offliner.
   PumpLoop();
@@ skipping 70 matching lines @@
       base::Bind(&RequestCoordinatorTest::GetRequestsDone,
                  base::Unretained(this)));
   PumpLoop();
 
   // Still one request in the queue.
   EXPECT_EQ(1UL, last_requests().size());
   // TODO(dougarnett): Verify retry count gets incremented.
 }
 
 }  // namespace offline_pages