Add a new file descriptor watch API.

base/files/file_descriptor_watcher_posix_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 "base/files/file_descriptor_watcher_posix.h"
+
+#include <unistd.h>
+
+#include <memory>
+
+#include "base/bind.h"
+#include "base/files/file_util.h"
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/run_loop.h"
+#include "base/test/test_timeouts.h"
+#include "base/threading/platform_thread.h"
+#include "base/threading/thread.h"
+#include "base/threading/thread_checker_impl.h"
+#include "build/build_config.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+class Mock {
+ public:
+  Mock() = default;
+
+  MOCK_METHOD0(ReadableCallback, void());
+  MOCK_METHOD0(WritableCallback, void());
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Mock);
+};
+
+enum class FileDescriptorWatcherTestType {
+  MESSAGE_LOOP_FOR_IO_ON_MAIN_THREAD,
+  MESSAGE_LOOP_FOR_IO_ON_OTHER_THREAD,
+};
+
+class FileDescriptorWatcherTest
+    : public testing::TestWithParam<FileDescriptorWatcherTestType> {
+ public:
+  FileDescriptorWatcherTest()
+      : message_loop_(GetParam() == FileDescriptorWatcherTestType::
+                                        MESSAGE_LOOP_FOR_IO_ON_MAIN_THREAD
+                          ? new MessageLoopForIO
+                          : new MessageLoop),
+        other_thread_("FileDescriptorWatcherTest_OtherThread") {}
+  ~FileDescriptorWatcherTest() override = default;
+
+  void SetUp() override {
+    ASSERT_EQ(0, pipe(pipe_fds_));
+
+    MessageLoop* message_loop_for_io;
+    if (GetParam() ==
+        FileDescriptorWatcherTestType::MESSAGE_LOOP_FOR_IO_ON_OTHER_THREAD) {
+      Thread::Options options;
+      options.message_loop_type = MessageLoop::TYPE_IO;
+      ASSERT_TRUE(other_thread_.StartWithOptions(options));
+      message_loop_for_io = other_thread_.message_loop();
+    } else {
+      message_loop_for_io = message_loop_.get();
+    }
+
+    ASSERT_TRUE(message_loop_for_io->IsType(MessageLoop::TYPE_IO));
+    file_descriptor_watcher_ = MakeUnique<FileDescriptorWatcher>(
+        static_cast<MessageLoopForIO*>(message_loop_for_io));
+  }
+
+  void TearDown() override {
+    if (GetParam() ==
+            FileDescriptorWatcherTestType::MESSAGE_LOOP_FOR_IO_ON_MAIN_THREAD &&
+        message_loop_) {
+      // Allow the delete task posted by the Controller's destructor to run.
+      base::RunLoop().RunUntilIdle();
+    }
+
+    EXPECT_EQ(0, IGNORE_EINTR(close(pipe_fds_[0])));
+    EXPECT_EQ(0, IGNORE_EINTR(close(pipe_fds_[1])));
+  }
+
+ protected:
+  int read_file_descriptor() const { return pipe_fds_[0]; }
+  int write_file_descriptor() const { return pipe_fds_[1]; }
+
+  // Waits for a short delay and run pending tasks.
+  void WaitAndRunPendingTasks() {
+    PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+    RunLoop().RunUntilIdle();
+  }
+
+  // Registers ReadableCallback() to be called on |mock_| when
+  // read_file_descriptor() is readable without blocking.
+  std::unique_ptr<FileDescriptorWatcher::Controller> WatchReadable() {
+    std::unique_ptr<FileDescriptorWatcher::Controller> controller =
+        FileDescriptorWatcher::WatchReadable(
+            read_file_descriptor(),
+            Bind(&Mock::ReadableCallback, Unretained(&mock_)));
+    EXPECT_TRUE(controller);
+
+    // Unless read_file_descriptor() was readable before the callback was
+    // registered, this shouldn't do anything.
+    WaitAndRunPendingTasks();
+
+    return controller;
+  }
+
+  // Registers WritableCallback() to be called on |mock_| when
+  // write_file_descriptor() is writable without blocking.
+  std::unique_ptr<FileDescriptorWatcher::Controller> WatchWritable() {
+    std::unique_ptr<FileDescriptorWatcher::Controller> controller =
+        FileDescriptorWatcher::WatchWritable(
+            read_file_descriptor(),
+            Bind(&Mock::WritableCallback, Unretained(&mock_)));
+    EXPECT_TRUE(controller);
+    return controller;
+  }
+
+  void WriteByte() {
+    constexpr char kByte = '!';
+    ASSERT_TRUE(
+        WriteFileDescriptor(write_file_descriptor(), &kByte, sizeof(kByte)));
+  }
+
+  void ReadByte() {
+    // This is always called as part of the WatchReadable() callback, which
+    // should run on the main thread.
+    EXPECT_TRUE(thread_checker_.CalledOnValidThread());
+
+    char buffer;
+    ASSERT_TRUE(ReadFromFD(read_file_descriptor(), &buffer, sizeof(buffer)));
+  }
+
+  // Mock on wich callbacks are invoked.
+  testing::StrictMock<Mock> mock_;
+
+  // MessageLoop bound to the main thread.
+  std::unique_ptr<MessageLoop> message_loop_;
+
+  // Thread running a MessageLoopForIO. Used when the test type is
+  // MESSAGE_LOOP_FOR_IO_ON_OTHER_THREAD.
+  Thread other_thread_;
+
+ private:
+  // Determines which MessageLoopForIO is used to watch file descriptors for
+  // which callbacks are registered on the main thread.
+  std::unique_ptr<FileDescriptorWatcher> file_descriptor_watcher_;
+
+  // Watched file descriptors.
+  int pipe_fds_[2];
+
+  // Used to verify that callbacks run on the thread on which they are
+  // registered.
+  ThreadCheckerImpl thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(FileDescriptorWatcherTest);
+};
+
+}  // namespace
+
+TEST_P(FileDescriptorWatcherTest, WatchWritable) {
+  auto controller = WatchWritable();
+
+// On Mac and iOS, the write end of a newly created pipe is writable without
+// blocking.
+#if defined(OS_MACOSX)
+  RunLoop run_loop;
+  EXPECT_CALL(mock_, WritableCallback())
+      .WillOnce(testing::Invoke(&run_loop, &RunLoop::Quit));
+  run_loop.Run();
+#endif  // defined(OS_MACOSX)
+}
+
+TEST_P(FileDescriptorWatcherTest, WatchReadableOneByte) {
+  auto controller = WatchReadable();
+
+  // Write 1 byte to the pipe, making it readable without blocking. Expect one
+  // call to ReadableCallback() which will read 1 byte from the pipe.
+  WriteByte();
+  RunLoop run_loop;
+  EXPECT_CALL(mock_, ReadableCallback())
+      .WillOnce(testing::Invoke([this, &run_loop]() {
+        ReadByte();
+        run_loop.Quit();
+      }));
+  run_loop.Run();
+  testing::Mock::VerifyAndClear(&mock_);
+
+  // No more call to ReadableCallback() is expected.
+  WaitAndRunPendingTasks();
+}
+
+TEST_P(FileDescriptorWatcherTest, WatchReadableTwoBytes) {
+  auto controller = WatchReadable();
+
+  // Write 2 bytes to the pipe. Expect two calls to ReadableCallback() which
+  // will each read 1 byte from the pipe.
+  WriteByte();
+  WriteByte();
+  RunLoop run_loop;
+  EXPECT_CALL(mock_, ReadableCallback())
+      .WillOnce(testing::Invoke([this]() { ReadByte(); }))
+      .WillOnce(testing::Invoke([this, &run_loop]() {
+        ReadByte();
+        run_loop.Quit();
+      }));
+  run_loop.Run();
+  testing::Mock::VerifyAndClear(&mock_);
+
+  // No more call to ReadableCallback() is expected.
+  WaitAndRunPendingTasks();
+}
+
+TEST_P(FileDescriptorWatcherTest, WatchReadableByteWrittenFromCallback) {
+  auto controller = WatchReadable();
+
+  // Write 1 byte to the pipe. Expect one call to ReadableCallback() from which
+  // 1 byte is read and 1 byte is written to the pipe. Then, expect another call
+  // to ReadableCallback() from which the remaining byte is read from the pipe.
+  WriteByte();
+  RunLoop run_loop;
+  EXPECT_CALL(mock_, ReadableCallback())
+      .WillOnce(testing::Invoke([this]() {
+        ReadByte();
+        WriteByte();
+      }))
+      .WillOnce(testing::Invoke([this, &run_loop]() {
+        ReadByte();
+        run_loop.Quit();
+      }));
+  run_loop.Run();
+  testing::Mock::VerifyAndClear(&mock_);
+
+  // No more call to ReadableCallback() is expected.
+  WaitAndRunPendingTasks();
+}
+
+TEST_P(FileDescriptorWatcherTest, DeleteControllerFromCallback) {
+  auto controller = WatchReadable();
+
+  // Write 1 byte to the pipe. Expect one call to ReadableCallback() from which
+  // |controller| is deleted.
+  WriteByte();
+  RunLoop run_loop;
+  EXPECT_CALL(mock_, ReadableCallback())
+      .WillOnce(testing::Invoke([&run_loop, &controller]() {
+        controller = nullptr;
+        run_loop.Quit();
+      }));
+  run_loop.Run();
+  testing::Mock::VerifyAndClear(&mock_);
+
+  // Since |controller| has been deleted, no call to ReadableCallback() is
+  // expected even though the pipe is still readable without blocking.
+  WaitAndRunPendingTasks();
+}
+
+TEST_P(FileDescriptorWatcherTest,
+       DeleteControllerBeforeFileDescriptorReadable) {
+  auto controller = WatchReadable();
+
+  // Cancel the watch.
+  controller = nullptr;
+
+  // Write 1 byte to the pipe to make it readable without blocking.
+  WriteByte();
+
+  // No call to ReadableCallback() is expected.
+  WaitAndRunPendingTasks();
+}
+
+TEST_P(FileDescriptorWatcherTest, DeleteControllerAfterFileDescriptorReadable) {
+  auto controller = WatchReadable();
+
+  // Write 1 byte to the pipe to make it readable without blocking.
+  WriteByte();
+
+  // Cancel the watch.
+  controller = nullptr;
+
+  // No call to ReadableCallback() is expected.
+  WaitAndRunPendingTasks();
+}
+
+TEST_P(FileDescriptorWatcherTest, DeleteControllerAfterDeleteMessageLoopForIO) {
+  auto controller = WatchReadable();
+
+  // Delete the MessageLoopForIO.
+  if (GetParam() ==
+      FileDescriptorWatcherTestType::MESSAGE_LOOP_FOR_IO_ON_MAIN_THREAD) {
+    message_loop_ = nullptr;
+  } else {
+    other_thread_.Stop();
+  }
+
+  // Deleting |controller| shouldn't crash even though that causes a task to be
+  // posted to the MessageLoopForIO thread.
+  controller = nullptr;
+}
+
+INSTANTIATE_TEST_CASE_P(
+    MessageLoopForIOOnMainThread,
+    FileDescriptorWatcherTest,
+    ::testing::Values(
+        FileDescriptorWatcherTestType::MESSAGE_LOOP_FOR_IO_ON_MAIN_THREAD));
+INSTANTIATE_TEST_CASE_P(
+    MessageLoopForIOOnOtherThread,
+    FileDescriptorWatcherTest,
+    ::testing::Values(
+        FileDescriptorWatcherTestType::MESSAGE_LOOP_FOR_IO_ON_OTHER_THREAD));
+
+}  // namespace base