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// Copyright (c) 2012 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 <set>
#include "base/basictypes.h"
#include "base/callback_forward.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/shared_memory.h"
#include "base/memory/singleton.h"
#include "base/threading/thread_checker.h"
#include "content/common/content_export.h"
namespace blink {
class WebGamepad;
namespace content {
class GamepadConsumer;
class GamepadDataFetcher;
class GamepadProvider;
class GamepadServiceTestConstructor;
class RenderProcessHost;
// Owns the GamepadProvider (the background polling thread) and keeps track of
// the number of consumers currently using the data (and pausing the provider
// when not in use).
class CONTENT_EXPORT GamepadService {
// Returns the GamepadService singleton.
static GamepadService* GetInstance();
// Increments the number of users of the provider. The Provider is running
// when there's > 0 users, and is paused when the count drops to 0.
// consumer is registered to listen for gamepad connections. If this is the
// first time it is added to the set of consumers it will be treated
// specially: it will not be informed about connections before a new user
// gesture is observed at which point it will be notified for every connected
// gamepads.
// Must be called on the I/O thread.
void ConsumerBecameActive(GamepadConsumer* consumer);
// Decrements the number of users of the provider. consumer will not be
// informed about connections until it's added back via ConsumerBecameActive.
// Must be matched with a ConsumerBecameActive call.
// Must be called on the I/O thread.
void ConsumerBecameInactive(GamepadConsumer* consumer);
// Decrements the number of users of the provider and removes consumer from
// the set of consumers. Should be matched with a a ConsumerBecameActive
// call.
// Must be called on the I/O thread.
void RemoveConsumer(GamepadConsumer* consumer);
// Registers the given closure for calling when the user has interacted with
// the device. This callback will only be issued once. Should only be called
// while a consumer is active.
void RegisterForUserGesture(const base::Closure& closure);
// Returns the shared memory handle of the gamepad data duplicated into the
// given process.
base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
base::ProcessHandle handle);
// Stop/join with the background thread in GamepadProvider |provider_|.
void Terminate();
// Called on IO thread when a gamepad is connected.
void OnGamepadConnected(int index, const blink::WebGamepad& pad);
// Called on IO thread when a gamepad is disconnected.
void OnGamepadDisconnected(int index, const blink::WebGamepad& pad);
friend struct DefaultSingletonTraits<GamepadService>;
friend class GamepadServiceTestConstructor;
friend class GamepadServiceTest;
// Constructor for testing. This specifies the data fetcher to use for a
// provider, bypassing the default platform one.
GamepadService(scoped_ptr<GamepadDataFetcher> fetcher);
virtual ~GamepadService();
static void SetInstance(GamepadService*);
void OnUserGesture();
struct ConsumerInfo {
ConsumerInfo(GamepadConsumer* consumer)
: consumer(consumer),
did_observe_user_gesture(false) {
bool operator<(const ConsumerInfo& other) const {
return consumer < other.consumer;
GamepadConsumer* consumer;
mutable bool is_active;
mutable bool did_observe_user_gesture;
scoped_ptr<GamepadProvider> provider_;
base::ThreadChecker thread_checker_;
typedef std::set<ConsumerInfo> ConsumerSet;
ConsumerSet consumers_;
int num_active_consumers_;
bool gesture_callback_pending_;
} // namespace content