[net/dns] Perform A/AAAA queries for AF_UNSPEC resolutions in parallel.

net/base/prioritized_dispatcher_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 <ctype.h>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 34 matching lines @@
           log_(log) {}
 
     bool running() const {
       return running_;
     }
 
     const PrioritizedDispatcher::Handle handle() const {
       return handle_;
     }
 
-    void Add() {
+    void Add(bool at_head) {
       CHECK(handle_.is_null());
       CHECK(!running_);
       size_t num_queued = dispatcher_->num_queued_jobs();
       size_t num_running = dispatcher_->num_running_jobs();
 
-      handle_ = dispatcher_->Add(this, priority_);
+      if (!at_head) {
+        handle_ = dispatcher_->Add(this, priority_);
+      } else {
+        handle_ = dispatcher_->AddAtHead(this, priority_);
+      }
 
       if (handle_.is_null()) {
         EXPECT_EQ(num_queued, dispatcher_->num_queued_jobs());
         EXPECT_TRUE(running_);
         EXPECT_EQ(num_running + 1, dispatcher_->num_running_jobs());
       } else {
         EXPECT_FALSE(running_);
         EXPECT_EQ(priority_, handle_.priority());
         EXPECT_EQ(tag_, reinterpret_cast<TestJob*>(handle_.value())->tag_);
         EXPECT_EQ(num_running, dispatcher_->num_running_jobs());
@@ skipping 61 matching lines @@
   };
 
  protected:
   void Prepare(const PrioritizedDispatcher::Limits& limits) {
     dispatcher_.reset(new PrioritizedDispatcher(limits));
   }
 
   TestJob* AddJob(char data, Priority priority) {
     TestJob* job = new TestJob(dispatcher_.get(), data, priority, &log_);
     jobs_.push_back(job);
-    job->Add();
+    job->Add(false);
+    return job;
+  }
+
+  TestJob* AddJobAtHead(char data, Priority priority) {
+    TestJob* job = new TestJob(dispatcher_.get(), data, priority, &log_);
+    jobs_.push_back(job);
+    job->Add(true);
     return job;
   }
 
   void Expect(std::string log) {
     EXPECT_EQ(0u, dispatcher_->num_queued_jobs());
     EXPECT_EQ(0u, dispatcher_->num_running_jobs());
     EXPECT_EQ(log, log_);
     log_.clear();
   }
 
@@ skipping 41 matching lines @@
   ASSERT_TRUE(job_d->running());
   job_d->Finish();
   ASSERT_TRUE(job_b->running());
   job_b->Finish();
   ASSERT_TRUE(job_e->running());
   job_e->Finish();
 
   Expect("a.c.d.b.e.");
 }
 
+TEST_F(PrioritizedDispatcherTest, AddAtHead) {
+  PrioritizedDispatcher::Limits limits(NUM_PRIORITIES, 1);
+  Prepare(limits);
+
+  TestJob* job_a = AddJob('a', MEDIUM);
+  TestJob* job_b = AddJobAtHead('b', MEDIUM);
+  TestJob* job_c = AddJobAtHead('c', HIGHEST);
+  TestJob* job_d = AddJobAtHead('d', HIGHEST);
+  TestJob* job_e = AddJobAtHead('e', MEDIUM);
+  TestJob* job_f = AddJob('f', MEDIUM);
+
+  ASSERT_TRUE(job_a->running());
+  job_a->Finish();
+  ASSERT_TRUE(job_d->running());
+  job_d->Finish();
+  ASSERT_TRUE(job_c->running());
+  job_c->Finish();
+  ASSERT_TRUE(job_e->running());
+  job_e->Finish();
+  ASSERT_TRUE(job_b->running());
+  job_b->Finish();
+  ASSERT_TRUE(job_f->running());
+  job_f->Finish();
+
+  Expect("a.d.c.e.b.f.");
+}
+
 TEST_F(PrioritizedDispatcherTest, EnforceLimits) {
   // Reserve 2 for HIGHEST and 1 for LOW or higher.
   // This leaves 2 for LOWEST or lower.
   PrioritizedDispatcher::Limits limits(NUM_PRIORITIES, 5);
   limits.reserved_slots[HIGHEST] = 2;
   limits.reserved_slots[LOW] = 1;
   Prepare(limits);
 
   TestJob* job_a = AddJob('a', IDLE);    // Uses unreserved slot.
   TestJob* job_b = AddJob('b', IDLE);    // Uses unreserved slot.
@@ skipping 141 matching lines @@
   Prepare(limits);
   AddJob('a', IDLE);
   AddJob('b', IDLE);
   EXPECT_DEBUG_DEATH(dispatcher_->Cancel(handle), "");
 }
 #endif  // GTEST_HAS_DEATH_TEST && !defined(NDEBUG)
 
 }  // namespace
 
 }  // namespace net