Safely cancel prerenders on threads other than the UI thread

chrome/browser/prerender/prerender_tracker_unittest.cc

+// Copyright (c) 2011 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 <set>
+
+#include "base/logging.h"
+#include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/prerender/prerender_tracker.h"
+#include "content/browser/browser_thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace prerender {
+
+namespace {
+
+class TestPrerenderManager : public PrerenderManager {
+ public:
+  TestPrerenderManager() : PrerenderManager(NULL) {
+    rate_limit_enabled_ = false;
+  }
+
+  virtual void DestroyPreloadForChildRouteIdPair(
+      const std::pair<int, int>& child_route_id_pair,
+      FinalStatus final_status) OVERRIDE {
+    cancelled_id_pairs_.insert(child_route_id_pair);
+  }
+
+  bool WasPrerenderCancelled(int child_id, int route_id) {
+    std::pair<int, int> child_route_id_pair(child_id, route_id);
+    return cancelled_id_pairs_.count(child_route_id_pair) != 0;
+  }
+
+  // Set of all the RenderViews that have been cancelled.
+  std::set<std::pair<int, int> > cancelled_id_pairs_;
+};
+
+}  // namespace
+
+class PrerenderTrackerTest : public testing::Test {
+ public:
+  PrerenderTrackerTest() :
+      ui_thread_(BrowserThread::UI, &message_loop_),
+      io_thread_(BrowserThread::IO, &message_loop_),
+      prerender_manager_(new TestPrerenderManager()) {
+  }
+
+  TestPrerenderManager* prerender_manager() {
+    return prerender_manager_.get();
+  }
+
+  PrerenderTracker* prerender_tracker() {
+    return PrerenderTracker::GetInstance();
+  }
+
+  int GetCurrentStatus(int child_id, int route_id) {
+    FinalStatus final_status;
+    if (!prerender_tracker()->GetFinalStatus(child_id, route_id,
+                                             &final_status)) {
+      return -1;
+    }
+    return final_status;
+  }
+
+  // Runs any tasks queued on either thread.
+  void RunEvents() {
+    message_loop_.RunAllPending();
+  }
+
+ private:
+  MessageLoop message_loop_;
+  BrowserThread ui_thread_;
+  BrowserThread io_thread_;
+
+  scoped_ptr<TestPrerenderManager> prerender_manager_;
+};
+
+// Check that a non-existant RenderView is handled correctly.
+TEST_F(PrerenderTrackerTest, PrerenderTrackerNull) {
+  FinalStatus final_status;
+  EXPECT_FALSE(prerender_tracker()->TryUse(0, 0));
+  EXPECT_FALSE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_FALSE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(0, 0, &final_status));
+  EXPECT_FALSE(prerender_manager()->WasPrerenderCancelled(0, 0));
+}
+
+// Check that a page that is used is handled correctly.
+TEST_F(PrerenderTrackerTest, PrerenderTrackerUsed) {
+  prerender_tracker()->OnPrerenderingStarted(0, 0, prerender_manager());
+  EXPECT_EQ(FINAL_STATUS_MAX, GetCurrentStatus(0, 0));
+
+  // This calls AddPrerenderOnIOThreadTask().
+  RunEvents();
+
+  EXPECT_TRUE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+  EXPECT_EQ(FINAL_STATUS_MAX, GetCurrentStatus(0, 0));
+
+  // Display the prerendered RenderView.
+  EXPECT_TRUE(prerender_tracker()->TryUse(0, 0));
+
+  // Make sure the page can't be destroyed or claim it was destroyed after
+  // it's been used.
+  EXPECT_FALSE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_FALSE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_EQ(FINAL_STATUS_USED, GetCurrentStatus(0, 0));
+
+  // This would call DestroyPreloadForChildRouteIdPair(), if the prerender were
+  // cancelled.
+  RunEvents();
+
+  // These functions should all behave as before.
+  EXPECT_FALSE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_FALSE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_EQ(FINAL_STATUS_USED, GetCurrentStatus(0, 0));
+
+  // This calls DestroyPreloadForChildRouteIdPair().
+  prerender_tracker()->OnPrerenderingFinished(0, 0);
+  EXPECT_TRUE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+
+  // This calls RemovePrerenderOnIOThreadTask().
+  RunEvents();
+
+  FinalStatus final_status;
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(0, 0, &final_status));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+  EXPECT_FALSE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_FALSE(prerender_manager()->WasPrerenderCancelled(0, 0));
+}
+
+// Check that a prerendered page cancelled by TryCancel() is handled correctly.
+TEST_F(PrerenderTrackerTest, PrerenderTrackerCancelled) {
+  prerender_tracker()->OnPrerenderingStarted(0, 0, prerender_manager());
+  EXPECT_EQ(FINAL_STATUS_MAX, GetCurrentStatus(0, 0));
+
+  // This calls AddPrerenderOnIOThreadTask().
+  RunEvents();
+
+  // Cancel the prerender.
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+
+  EXPECT_FALSE(prerender_tracker()->TryUse(0, 0));
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_EQ(FINAL_STATUS_HTTPS, GetCurrentStatus(0, 0));
+
+  // This calls DestroyPreloadForChildRouteIdPair().
+  RunEvents();
+  EXPECT_TRUE(prerender_manager()->WasPrerenderCancelled(0, 0));
+
+  // These should all work until the prerendering RenderViewHost is destroyed.
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_EQ(FINAL_STATUS_HTTPS, GetCurrentStatus(0, 0));
+
+  prerender_tracker()->OnPrerenderingFinished(0, 0);
+  EXPECT_TRUE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+
+  // This calls RemovePrerenderOnIOThreadTask().
+  RunEvents();
+
+  FinalStatus final_status;
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(0, 0, &final_status));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+}
+
+// Check that a prerendered page cancelled on the IO thread by
+// TryCancelOnIOThread() is handled correctly.
+TEST_F(PrerenderTrackerTest, PrerenderTrackerCancelledOnIO) {
+  prerender_tracker()->OnPrerenderingStarted(0, 0, prerender_manager());
+  EXPECT_EQ(FINAL_STATUS_MAX, GetCurrentStatus(0, 0));
+
+  // This calls AddPrerenderOnIOThreadTask().
+  RunEvents();
+
+  // Cancel the prerender.
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_TIMED_OUT));
+
+  EXPECT_FALSE(prerender_tracker()->TryUse(0, 0));
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_EQ(FINAL_STATUS_TIMED_OUT, GetCurrentStatus(0, 0));
+
+  // This calls DestroyPreloadForChildRouteIdPair().
+  RunEvents();
+  EXPECT_TRUE(prerender_manager()->WasPrerenderCancelled(0, 0));
+
+  // These should all work until the prerendering RenderViewHost is destroyed.
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_EQ(FINAL_STATUS_TIMED_OUT, GetCurrentStatus(0, 0));
+
+  prerender_tracker()->OnPrerenderingFinished(0, 0);
+  EXPECT_TRUE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+
+  // This calls RemovePrerenderOnIOThreadTask().
+  RunEvents();
+
+  FinalStatus final_status;
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(0, 0, &final_status));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+}
+
+// Check that a prerendered page cancelled before it reaches the IO thread is
+// handled correctly.
+TEST_F(PrerenderTrackerTest, PrerenderTrackerCancelledFast) {
+  prerender_tracker()->OnPrerenderingStarted(0, 0, prerender_manager());
+  // Cancel the prerender.
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+
+  EXPECT_FALSE(prerender_tracker()->TryUse(0, 0));
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_TIMED_OUT));
+
+  // This calls AddPrerenderOnIOThreadTask() and
+  // DestroyPreloadForChildRouteIdPair().
+  RunEvents();
+  EXPECT_TRUE(prerender_manager()->WasPrerenderCancelled(0, 0));
+
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_TRUE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_TIMED_OUT));
+  EXPECT_EQ(FINAL_STATUS_HTTPS, GetCurrentStatus(0, 0));
+
+  prerender_tracker()->OnPrerenderingFinished(0, 0);
+
+  // This calls RemovePrerenderOnIOThreadTask().
+  RunEvents();
+
+  FinalStatus final_status;
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(0, 0, &final_status));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+}
+
+// Check that handling two pages at once works.
+TEST_F(PrerenderTrackerTest, PrerenderTrackerMultiple) {
+  prerender_tracker()->OnPrerenderingStarted(0, 0, prerender_manager());
+
+  // This calls AddPrerenderOnIOThreadTask().
+  RunEvents();
+  EXPECT_TRUE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(1, 2));
+  EXPECT_FALSE(prerender_tracker()->TryUse(1, 2));
+  EXPECT_FALSE(prerender_tracker()->TryCancel(1, 2, FINAL_STATUS_HTTPS));
+
+  // Start second prerender.
+  prerender_tracker()->OnPrerenderingStarted(1, 2, prerender_manager());
+  // This calls AddPrerenderOnIOThreadTask().
+  RunEvents();
+
+  // Use (0, 0).
+  EXPECT_TRUE(prerender_tracker()->TryUse(0, 0));
+  EXPECT_EQ(FINAL_STATUS_USED, GetCurrentStatus(0, 0));
+  EXPECT_EQ(FINAL_STATUS_MAX, GetCurrentStatus(1, 2));
+
+  // Cancel (1, 2).
+  EXPECT_TRUE(prerender_tracker()->TryCancelOnIOThread(
+      1, 2, FINAL_STATUS_HTTPS));
+
+  EXPECT_FALSE(prerender_tracker()->TryCancel(0, 0, FINAL_STATUS_HTTPS));
+  EXPECT_EQ(FINAL_STATUS_USED, GetCurrentStatus(0, 0));
+
+  EXPECT_FALSE(prerender_tracker()->TryUse(1, 2));
+  EXPECT_TRUE(prerender_tracker()->TryCancel(1, 2, FINAL_STATUS_HTTPS));
+  EXPECT_EQ(FINAL_STATUS_HTTPS, GetCurrentStatus(1, 2));
+
+  // This calls DestroyPreloadForChildRouteIdPair().
+  RunEvents();
+  EXPECT_FALSE(prerender_manager()->WasPrerenderCancelled(0, 0));
+  EXPECT_TRUE(prerender_manager()->WasPrerenderCancelled(1, 2));
+
+  prerender_tracker()->OnPrerenderingFinished(0, 0);
+  prerender_tracker()->OnPrerenderingFinished(1, 2);
+
+  // This calls RemovePrerenderOnIOThreadTask().
+  RunEvents();
+
+  FinalStatus final_status;
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(0, 0, &final_status));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(0, 0));
+
+  EXPECT_FALSE(prerender_tracker()->GetFinalStatus(1, 2, &final_status));
+  EXPECT_FALSE(prerender_tracker()->IsPrerenderingOnIOThread(1, 2));
+}
+
+}  // namespace prerender