Add gamepad hardware data fetcher, and higher level thread container

content/browser/gamepad/gamepad_provider_unittest.cc

+// Copyright (c) 2011 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/memory/scoped_ptr.h"
+#include "base/process_util.h"
+#include "base/system_monitor/system_monitor.h"
+#include "content/browser/gamepad/gamepad_provider.h"
+#include "content/common/gamepad_messages.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+class MockDataFetcher : public gamepad::DataFetcher {
+ public:
+  MockDataFetcher() : read_data_(false) {
+    memset(&test_data, 0, sizeof(test_data));
+  }
+  virtual void GetGamepadData(WebKit::WebGamepads* pads,
+                              bool devices_changed_hint) OVERRIDE {
+    *pads = test_data;
+    read_data_ = true;
+  }
+
+  void SetData(WebKit::WebGamepads& data) {
+    test_data = data;
+    read_data_ = false;
+  }
+
+  bool ReadData() const { return read_data_; }
+
+  WebKit::WebGamepads test_data;
+  bool read_data_;
+};
+
+// Main test fixture
+class GamepadProviderTest : public testing::Test {
+ public:
+  gamepad::Provider* CreateProvider() {
+#if defined(OS_MACOSX)
+    base::SystemMonitor::AllocateSystemIOPorts();
+#endif
+    system_monitor_.reset(new base::SystemMonitor);
+    mock_data_fetcher_ = new MockDataFetcher;
+    provider_ = new gamepad::Provider(mock_data_fetcher_);
+    return provider_.get();
+  }
+
+ protected:
+  GamepadProviderTest() {
+  }
+
+  MessageLoop main_message_loop_;
+  scoped_ptr<base::SystemMonitor> system_monitor_;
+  MockDataFetcher* mock_data_fetcher_;
+  scoped_refptr<gamepad::Provider> provider_;
+};
+
+TEST_F(GamepadProviderTest, BasicStartStop) {
+  gamepad::Provider* provider = CreateProvider();
+  provider->Start();
+  provider->Stop();
+  // Just ensure that there's no asserts on startup, shutdown, or destroy.
+}
+
+TEST_F(GamepadProviderTest, PollingAccess) {
+  using namespace gamepad;
+
+  Provider* provider = CreateProvider();
+  provider->Start();
+
+  WebKit::WebGamepads test_data;
+  test_data.length = 1;
+  test_data.items[0].connected = true;
+  test_data.items[0].timestamp = 0;
+  test_data.items[0].buttonsLength = 1;
+  test_data.items[0].axesLength = 2;
+  test_data.items[0].buttons[0] = 1.f;
+  test_data.items[0].axes[0] = -1.f;
+  test_data.items[0].axes[1] = .5f;
+  mock_data_fetcher_->SetData(test_data);
+
+  main_message_loop_.RunAllPending();
+
+  while (!mock_data_fetcher_->ReadData()) {
+    base::PlatformThread::Sleep(10);

[Paweł Hajdan Jr., 2011/11/18 11:59:07]

Sorry, this is still bad. Please wait for en _event_, i.e. data_available.Wait()
(base::WaitableEvent). Or maybe TimedWait if you want a timeout.

+  }
+
+  // Renderer-side, pull data out of poll buffer.
+  base::SharedMemoryHandle handle =
+      provider->GetRendererSharedMemoryHandle(base::GetCurrentProcessHandle());
+  base::SharedMemory* shared_memory = new base::SharedMemory(handle, true);
+  EXPECT_TRUE(shared_memory->Map(sizeof(GamepadHardwareBuffer)));
+  void* mem = shared_memory->memory();
+
+  GamepadHardwareBuffer* hwbuf = static_cast<GamepadHardwareBuffer*>(mem);
+  // See gamepad_hardware_buffer.h for details on the read discipline.
+  base::subtle::Atomic32 start, end;
+  int contention_count = 0;
+  WebKit::WebGamepads output;
+  for (;;) {
+    end = base::subtle::Acquire_Load(&hwbuf->end_marker);
+    memcpy(&output, &hwbuf->buffer, sizeof(output));
+    start = base::subtle::Acquire_Load(&hwbuf->start_marker);
+    if (start == end) break;
+    ++contention_count;
+    base::PlatformThread::YieldCurrentThread();
+    EXPECT_LT(10, contention_count);

[Paweł Hajdan Jr., 2011/11/18 11:59:07]

This will still make the test hang if you're unlucky. Is there really no other
way to query this? Is it the way "production code" queries the buffer?

Suggestion: maybe instead of waiting for start marker and end marker to align,
we can wait for some number of units in the buffer, and just take that? I didn't
read other code here, but I'm really suspicious when seeing loops like that.

+  }
+
+  EXPECT_EQ(1u, output.length);
+  EXPECT_EQ(1u, output.items[0].buttonsLength);
+  EXPECT_EQ(1.f, output.items[0].buttons[0]);
+  EXPECT_EQ(2u, output.items[0].axesLength);
+  EXPECT_EQ(-1.f, output.items[0].axes[0]);
+  EXPECT_EQ(0.5f, output.items[0].axes[1]);
+
+  provider->Stop();
+}
+
+}  // namespace