Initial in-process implementation of some Mojo primitives.

mojo/system/waiter_unittest.cc

+// Copyright 2013 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.
+
+// NOTE(vtl): These tests are inherently flaky (e.g., if run on a heavily-loaded
+// system). Sorry. |kEpsilonMicros| may be increased to increase tolerance and
+// reduce observed flakiness.
+
+#include "mojo/system/waiter.h"
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/synchronization/lock.h"
+#include "base/threading/platform_thread.h"  // For |Sleep()|.
+#include "base/threading/simple_thread.h"
+#include "base/time/time.h"
+#include "mojo/system/test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace system {
+namespace {
+
+const int64_t kMicrosPerMs = 1000;
+const int64_t kEpsilonMicros = 15 * kMicrosPerMs;  // 15 ms.
+const int64_t kPollTimeMicros = 10 * kMicrosPerMs;  // 10 ms.
+
+class WaitingThread : public base::SimpleThread {
+ public:
+  explicit WaitingThread(MojoDeadline deadline)
+      : base::SimpleThread("waiting_thread"),
+        deadline_(deadline),
+        done_(false),
+        result_(MOJO_RESULT_UNKNOWN),
+        elapsed_micros_(-1) {
+    waiter_.Init();
+  }
+
+  virtual ~WaitingThread() {
+    Join();
+  }
+
+  void WaitUntilDone(MojoResult* result, int64_t* elapsed_micros) {
+    for (;;) {
+      {
+        base::AutoLock locker(lock_);
+        if (done_) {
+          *result = result_;
+          *elapsed_micros = elapsed_micros_;
+          break;
+        }
+      }
+
+      base::PlatformThread::Sleep(
+          base::TimeDelta::FromMicroseconds(kPollTimeMicros));
+    }
+  }
+
+  Waiter* waiter() { return &waiter_; }
+
+ private:
+  virtual void Run() OVERRIDE {
+    test::Stopwatch stopwatch;
+    MojoResult result;
+    int64_t elapsed_micros;
+
+    stopwatch.Start();
+    result = waiter_.Wait(deadline_);
+    elapsed_micros = stopwatch.Elapsed();
+
+    {
+      base::AutoLock locker(lock_);
+      done_ = true;
+      result_ = result;
+      elapsed_micros_ = elapsed_micros;
+    }
+  }
+
+  const MojoDeadline deadline_;
+  Waiter waiter_;  // Thread-safe.
+
+  base::Lock lock_;  // Protects the following members.
+  bool done_;
+  MojoResult result_;
+  int64_t elapsed_micros_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaitingThread);
+};
+
+TEST(WaiterTest, Basic) {
+  MojoResult result;
+  int64_t elapsed_micros;
+
+  // Finite deadline.
+
+  // Awake immediately after thread start.
+  {
+    WaitingThread thread(static_cast<MojoDeadline>(10 * kEpsilonMicros));
+    thread.Start();
+    thread.waiter()->Awake(0);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(0, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  // Awake before after thread start.
+  {
+    WaitingThread thread(static_cast<MojoDeadline>(10 * kEpsilonMicros));
+    thread.waiter()->Awake(MOJO_RESULT_CANCELLED);
+    thread.Start();
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(MOJO_RESULT_CANCELLED, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  // Awake some time after thread start.
+  {
+    WaitingThread thread(static_cast<MojoDeadline>(10 * kEpsilonMicros));
+    thread.Start();
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+    thread.waiter()->Awake(1);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(1, result);
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+  }
+
+  // Awake some longer time after thread start.
+  {
+    WaitingThread thread(static_cast<MojoDeadline>(10 * kEpsilonMicros));
+    thread.Start();
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(5 * kEpsilonMicros));
+    thread.waiter()->Awake(1);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(1, result);
+    EXPECT_GT(elapsed_micros, (5-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (5+1) * kEpsilonMicros);
+  }
+
+  // Don't awake -- time out (on another thread).
+  {
+    WaitingThread thread(static_cast<MojoDeadline>(2 * kEpsilonMicros));
+    thread.Start();
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED, result);
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+  }
+
+  // No (indefinite) deadline.
+
+  // Awake immediately after thread start.
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.Start();
+    thread.waiter()->Awake(0);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(0, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  // Awake before after thread start.
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.waiter()->Awake(MOJO_RESULT_CANCELLED);
+    thread.Start();
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(MOJO_RESULT_CANCELLED, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  // Awake some time after thread start.
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.Start();
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+    thread.waiter()->Awake(1);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(1, result);
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+  }
+
+  // Awake some longer time after thread start.
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.Start();
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(5 * kEpsilonMicros));
+    thread.waiter()->Awake(1);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(1, result);
+    EXPECT_GT(elapsed_micros, (5-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (5+1) * kEpsilonMicros);
+  }
+}
+
+TEST(WaiterTest, TimeOut) {
+  test::Stopwatch stopwatch;
+  int64_t elapsed_micros;
+
+  Waiter waiter;
+
+  waiter.Init();
+  stopwatch.Start();
+  EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED, waiter.Wait(0));
+  elapsed_micros = stopwatch.Elapsed();
+  EXPECT_LT(elapsed_micros, kEpsilonMicros);
+
+  waiter.Init();
+  stopwatch.Start();
+  EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED,
+            waiter.Wait(static_cast<MojoDeadline>(2 * kEpsilonMicros)));
+  elapsed_micros = stopwatch.Elapsed();
+  EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+  EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+
+  waiter.Init();
+  stopwatch.Start();
+  EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED,
+            waiter.Wait(static_cast<MojoDeadline>(5 * kEpsilonMicros)));
+  elapsed_micros = stopwatch.Elapsed();
+  EXPECT_GT(elapsed_micros, (5-1) * kEpsilonMicros);
+  EXPECT_LT(elapsed_micros, (5+1) * kEpsilonMicros);
+}
+
+// The first |Awake()| should always win.
+TEST(WaiterTest, MultipleAwakes) {
+  MojoResult result;
+  int64_t elapsed_micros;
+
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.Start();
+    thread.waiter()->Awake(0);
+    thread.waiter()->Awake(1);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(0, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.waiter()->Awake(1);
+    thread.Start();
+    thread.waiter()->Awake(0);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(1, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  {
+    WaitingThread thread(MOJO_DEADLINE_INDEFINITE);
+    thread.Start();
+    thread.waiter()->Awake(10);
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+    thread.waiter()->Awake(20);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(10, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+  }
+
+  {
+    WaitingThread thread(static_cast<MojoDeadline>(10 * kEpsilonMicros));
+    thread.Start();
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(1 * kEpsilonMicros));
+    thread.waiter()->Awake(MOJO_RESULT_FAILED_PRECONDITION);
+    base::PlatformThread::Sleep(
+        base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+    thread.waiter()->Awake(0);
+    thread.WaitUntilDone(&result, &elapsed_micros);
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION, result);
+    EXPECT_GT(elapsed_micros, (1-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (1+1) * kEpsilonMicros);
+  }
+}
+
+}  // namespace
+}  // namespace system
+}  // namespace mojo