Allow SequencedTaskRunnerHandle::Get() while running unsequenced tasks.

base/threading/sequenced_worker_pool_unittest.cc

 // Copyright (c) 2012 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 "base/threading/sequenced_worker_pool.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 886 matching lines @@
   // Should be fine to call on an idle instance with all threads created, and
   // spamming the method shouldn't deadlock or confuse the class.
   pool()->FlushForTesting();
   pool()->FlushForTesting();
 
   // Should be fine to call after shutdown too.
   pool()->Shutdown();
   pool()->FlushForTesting();
 }
 
-namespace {
-
-void CheckWorkerPoolAndSequenceToken(
-    const scoped_refptr<SequencedWorkerPool>& expected_pool,
-    SequencedWorkerPool::SequenceToken expected_token) {
-  SequencedWorkerPool::SequenceToken token =
-      SequencedWorkerPool::GetSequenceTokenForCurrentThread();
-  EXPECT_EQ(expected_token.ToString(), token.ToString());
-
-  scoped_refptr<SequencedWorkerPool> pool =
-      SequencedWorkerPool::GetWorkerPoolForCurrentThread();
-  EXPECT_EQ(expected_pool, pool);
+void VerifySequencedTaskRunner(

[gab, 2015/11/10 19:54:19]

IsSameSequence() or something?  (+ a commment?) -- i.e., it's not clear to me
from the name what this is meant to do without reading the calling code.

[Bernhard Bauer, 2015/11/10 20:31:47]

Done -- tried to make the name as descriptive as possible.

+    const scoped_refptr<SequencedTaskRunner>& task_runner) {
+  EXPECT_TRUE(task_runner->RunsTasksOnCurrentThread());
 }
 
-}  // namespace
+void GetCurrentSequencedTaskRunner(

[gab, 2015/11/10 19:54:19]

Again, a "Get" method that returns void feels weird to me.

Maybe, VerifyCurrentTaskRunner?

[Bernhard Bauer, 2015/11/10 20:31:47]

Done.

+    scoped_refptr<SequencedTaskRunner> expected_task_runner) {
+  scoped_refptr<SequencedTaskRunner> task_runner =
+      SequencedWorkerPool::GetSequencedTaskRunnerForCurrentThread();
 
-TEST_F(SequencedWorkerPoolTest, GetWorkerPoolAndSequenceTokenForCurrentThread) {
+  // If the expected task runner is null, get another one for the current
+  // thread. They should be the same.
+  if (!expected_task_runner) {
+    expected_task_runner =
+        SequencedWorkerPool::GetSequencedTaskRunnerForCurrentThread();
+  }
+
+  // SequencedTaskRunner does not allow directly checking for equality, but we
+  // can post a task to one task runner and verify that the other task runner
+  // is on the same sequence.
+  task_runner->PostTask(
+      FROM_HERE, base::Bind(&VerifySequencedTaskRunner, expected_task_runner));
+}
+
+TEST_F(SequencedWorkerPoolTest, GetSequencedTaskRunnerForCurrentThread) {
   EnsureAllWorkersCreated();
 
-  // The current thread should have neither a worker pool nor a sequence token.
-  SequencedWorkerPool::SequenceToken local_token =
-      SequencedWorkerPool::GetSequenceTokenForCurrentThread();
-  scoped_refptr<SequencedWorkerPool> local_pool =
-      SequencedWorkerPool::GetWorkerPoolForCurrentThread();
-  EXPECT_FALSE(local_token.IsValid()) << local_token.ToString();
-  EXPECT_FALSE(local_pool);
+  // The current thread should not have a sequenced task runner from a
+  // worker pool.
+  scoped_refptr<SequencedTaskRunner> local_task_runner =
+      SequencedWorkerPool::GetSequencedTaskRunnerForCurrentThread();
+  EXPECT_FALSE(local_task_runner);
 
-  SequencedWorkerPool::SequenceToken token1 = pool()->GetSequenceToken();
-  SequencedWorkerPool::SequenceToken token2 = pool()->GetSequenceToken();
-  pool()->PostSequencedWorkerTask(
-      token1, FROM_HERE,
-      base::Bind(&CheckWorkerPoolAndSequenceToken, pool(), token1));
-  pool()->PostSequencedWorkerTask(
-      token2, FROM_HERE,
-      base::Bind(&CheckWorkerPoolAndSequenceToken, pool(), token2));
+  scoped_refptr<SequencedTaskRunner> task_runner_1 =
+      pool()->GetSequencedTaskRunner(SequencedWorkerPool::GetSequenceToken());
+  scoped_refptr<SequencedTaskRunner> task_runner_2 =
+      pool()->GetSequencedTaskRunner(SequencedWorkerPool::GetSequenceToken());
+  task_runner_1->PostTask(
+      FROM_HERE, base::Bind(&GetCurrentSequencedTaskRunner, task_runner_1));
+  task_runner_2->PostTask(
+      FROM_HERE, base::Bind(&GetCurrentSequencedTaskRunner, task_runner_2));
 
   pool()->PostWorkerTask(FROM_HERE,
-                         base::Bind(&CheckWorkerPoolAndSequenceToken, pool(),
-                                    SequencedWorkerPool::SequenceToken()));
+                         base::Bind(&GetCurrentSequencedTaskRunner, nullptr));
 
   pool()->FlushForTesting();
+  pool()->Shutdown();
 }
 
 TEST(SequencedWorkerPoolRefPtrTest, ShutsDownCleanWithContinueOnShutdown) {
   MessageLoop loop;
   scoped_refptr<SequencedWorkerPool> pool(new SequencedWorkerPool(3, "Pool"));
   scoped_refptr<SequencedTaskRunner> task_runner =
       pool->GetSequencedTaskRunnerWithShutdownBehavior(
           pool->GetSequenceToken(),
           base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 
@@ skipping 120 matching lines @@
     SequencedWorkerPoolSequencedTaskRunner, SequencedTaskRunnerTest,
     SequencedWorkerPoolSequencedTaskRunnerTestDelegate);
 INSTANTIATE_TYPED_TEST_CASE_P(
     SequencedWorkerPoolSequencedTaskRunner,
     SequencedTaskRunnerDelayedTest,
     SequencedWorkerPoolSequencedTaskRunnerTestDelegate);
 
 }  // namespace
 
 }  // namespace base