Make AsyncHandleWaiter reenterancy-safe

ipc/mojo/async_handle_waiter_unittest.cc

 // Copyright 2015 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 "ipc/mojo/async_handle_waiter.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/threading/thread.h"
@@ skipping 186 matching lines @@
   EXPECT_EQ(MOJO_RESULT_OK, Start());
   WriteToPipe();
   run_loop_->Run();
 
   EXPECT_TRUE(handler.IsClosingHandled());
 
   // |HandlerThatReenters::RestartAndClose| already closed it.
   ignore_result(pipe_to_read_.release());
 }
 
+class AsyncHandleWaiterIOObserverTest : public testing::Test {
+ public:
+  void SetUp() override {
+    message_loop_.reset(new base::MessageLoopForIO());
+    target_.reset(new AsyncHandleWaiter(
+        base::Bind(&AsyncHandleWaiterIOObserverTest::HandleIsReady,
+                   base::Unretained(this))));
+    invocation_count_ = 0;
+  }
+
+  void HandleIsReady(MojoResult result) { invocation_count_++; }
+
+  scoped_ptr<base::MessageLoop> message_loop_;
+  scoped_ptr<AsyncHandleWaiter> target_;
+  size_t invocation_count_;
+};
+
+TEST_F(AsyncHandleWaiterIOObserverTest, OutsideIOEvnet) {
+  target_->GetWaitCallbackForTest().Run(MOJO_RESULT_OK);
+  EXPECT_EQ(0U, invocation_count_);
+  message_loop_->RunUntilIdle();
+  EXPECT_EQ(1U, invocation_count_);
+}
+
+TEST_F(AsyncHandleWaiterIOObserverTest, InsideIOEvnet) {
+  target_->GetIOObserverForTest()->WillProcessIOEvent();
+  target_->GetWaitCallbackForTest().Run(MOJO_RESULT_OK);
+  EXPECT_EQ(0U, invocation_count_);
+  target_->GetIOObserverForTest()->DidProcessIOEvent();
+  EXPECT_EQ(1U, invocation_count_);
+}
+
+TEST_F(AsyncHandleWaiterIOObserverTest, Reenter) {
+  target_->GetIOObserverForTest()->WillProcessIOEvent();
+  target_->GetWaitCallbackForTest().Run(MOJO_RESULT_OK);
+  EXPECT_EQ(0U, invocation_count_);
+
+  // As if some other io handler start nested loop.
+  target_->GetIOObserverForTest()->WillProcessIOEvent();
+  target_->GetWaitCallbackForTest().Run(MOJO_RESULT_OK);
+  target_->GetIOObserverForTest()->DidProcessIOEvent();
+  EXPECT_EQ(0U, invocation_count_);
+
+  target_->GetIOObserverForTest()->DidProcessIOEvent();
+  EXPECT_EQ(1U, invocation_count_);
+}
+
 }  // namespace
 }  // namespace internal
 }  // namespace IPC