Revert of Mojo: Armed Watchers

mojo/public/cpp/system/tests/watcher_unittest.cc

Index: mojo/public/cpp/system/tests/watcher_unittest.cc
diff --git a/mojo/public/cpp/system/tests/watcher_unittest.cc b/mojo/public/cpp/system/tests/watcher_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9b59240c5dcdf82b865ed07f53a5c06ee79af17d
--- /dev/null
+++ b/mojo/public/cpp/system/tests/watcher_unittest.cc
@@ -0,0 +1,181 @@
+// 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 "mojo/public/cpp/system/watcher.h"
+
+#include <memory>
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "mojo/public/c/system/types.h"
+#include "mojo/public/cpp/system/message_pipe.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace {
+
+template <typename Handler>
+void RunResultHandler(Handler f, MojoResult result) { f(result); }
+
+template <typename Handler>
+Watcher::ReadyCallback OnReady(Handler f) {
+  return base::Bind(&RunResultHandler<Handler>, f);
+}
+
+Watcher::ReadyCallback NotReached() {
+  return OnReady([] (MojoResult) { NOTREACHED(); });
+}
+
+class WatcherTest : public testing::Test {
+ public:
+  WatcherTest() {}
+  ~WatcherTest() override {}
+
+ private:
+  base::MessageLoop message_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(WatcherTest);
+};
+
+TEST_F(WatcherTest, WatchBasic) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+
+  bool notified = false;
+  base::RunLoop run_loop;
+  Watcher b_watcher(FROM_HERE);
+  EXPECT_EQ(MOJO_RESULT_OK,
+            b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                            OnReady([&] (MojoResult result) {
+                              EXPECT_EQ(MOJO_RESULT_OK, result);
+                              notified = true;
+                              run_loop.Quit();
+                            })));
+  EXPECT_TRUE(b_watcher.IsWatching());
+
+  EXPECT_EQ(MOJO_RESULT_OK, WriteMessageRaw(a.get(), "hello", 5, nullptr, 0,
+                                            MOJO_WRITE_MESSAGE_FLAG_NONE));
+  run_loop.Run();
+  EXPECT_TRUE(notified);
+
+  b_watcher.Cancel();
+}
+
+TEST_F(WatcherTest, WatchUnsatisfiable) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+  a.reset();
+
+  Watcher b_watcher(FROM_HERE);
+  EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
+            b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                            NotReached()));
+  EXPECT_FALSE(b_watcher.IsWatching());
+}
+
+TEST_F(WatcherTest, WatchInvalidHandle) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+  a.reset();
+  b.reset();
+
+  Watcher b_watcher(FROM_HERE);
+  EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
+            b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                            NotReached()));
+  EXPECT_FALSE(b_watcher.IsWatching());
+}
+
+TEST_F(WatcherTest, Cancel) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+
+  base::RunLoop run_loop;
+  Watcher b_watcher(FROM_HERE);
+  EXPECT_EQ(MOJO_RESULT_OK,
+            b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                            NotReached()));
+  EXPECT_TRUE(b_watcher.IsWatching());
+  b_watcher.Cancel();
+  EXPECT_FALSE(b_watcher.IsWatching());
+
+  // This should never trigger the watcher.
+  EXPECT_EQ(MOJO_RESULT_OK, WriteMessageRaw(a.get(), "hello", 5, nullptr, 0,
+                                            MOJO_WRITE_MESSAGE_FLAG_NONE));
+
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, run_loop.QuitClosure());
+  run_loop.Run();
+}
+
+TEST_F(WatcherTest, CancelOnClose) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+
+  base::RunLoop run_loop;
+  Watcher b_watcher(FROM_HERE);
+  EXPECT_EQ(MOJO_RESULT_OK,
+            b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                            OnReady([&] (MojoResult result) {
+                              EXPECT_EQ(MOJO_RESULT_CANCELLED, result);
+                              run_loop.Quit();
+                            })));
+  EXPECT_TRUE(b_watcher.IsWatching());
+
+  // This should trigger the watcher above.
+  b.reset();
+
+  run_loop.Run();
+
+  EXPECT_FALSE(b_watcher.IsWatching());
+}
+
+TEST_F(WatcherTest, CancelOnDestruction) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+  base::RunLoop run_loop;
+  {
+    Watcher b_watcher(FROM_HERE);
+    EXPECT_EQ(MOJO_RESULT_OK,
+              b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                              NotReached()));
+    EXPECT_TRUE(b_watcher.IsWatching());
+
+    // |b_watcher| should be cancelled when it goes out of scope.
+  }
+
+  // This should never trigger the watcher above.
+  EXPECT_EQ(MOJO_RESULT_OK, WriteMessageRaw(a.get(), "hello", 5, nullptr, 0,
+                                            MOJO_WRITE_MESSAGE_FLAG_NONE));
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, run_loop.QuitClosure());
+  run_loop.Run();
+}
+
+TEST_F(WatcherTest, CloseAndCancel) {
+  ScopedMessagePipeHandle a, b;
+  CreateMessagePipe(nullptr, &a, &b);
+
+  Watcher b_watcher(FROM_HERE);
+  EXPECT_EQ(MOJO_RESULT_OK,
+            b_watcher.Start(b.get(), MOJO_HANDLE_SIGNAL_READABLE,
+                            OnReady([](MojoResult result) { FAIL(); })));
+  EXPECT_TRUE(b_watcher.IsWatching());
+
+  // This should trigger the watcher above...
+  b.reset();
+  // ...but the watcher is cancelled first.
+  b_watcher.Cancel();
+
+  EXPECT_FALSE(b_watcher.IsWatching());
+
+  base::RunLoop().RunUntilIdle();
+}
+
+}  // namespace
+}  // namespace mojo