C++ common::FifoQueue类代码示例

namespace CoreTiming
{
struct EventType
{
    TimedCallback callback;
    const std::string* name;
};

struct Event
{
    s64 time;
    u64 fifo_order;
    u64 userdata;
    EventType* type;
};

// Sort by time, unless the times are the same, in which case sort by the order added to the queue
static bool operator>(const Event& left, const Event& right)
{
    return std::tie(left.time, left.fifo_order) > std::tie(right.time, right.fifo_order);
}
static bool operator<(const Event& left, const Event& right)
{
    return std::tie(left.time, left.fifo_order) < std::tie(right.time, right.fifo_order);
}

// unordered_map stores each element separately as a linked list node so pointers to elements
// remain stable regardless of rehashes/resizing.
static std::unordered_map<std::string, EventType> s_event_types;

// STATE_TO_SAVE
// The queue is a min-heap using std::make_heap/push_heap/pop_heap.
// We don't use std::priority_queue because we need to be able to serialize, unserialize and
// erase arbitrary events (RemoveEvent()) regardless of the queue order. These aren't accomodated
// by the standard adaptor class.
static std::vector<Event> s_event_queue;
static u64 s_event_fifo_id;
static std::mutex s_ts_write_lock;
static Common::FifoQueue<Event, false> s_ts_queue;

static float s_last_OC_factor;
float g_last_OC_factor_inverted;
int g_slice_length;
static constexpr int MAX_SLICE_LENGTH = 20000;

static s64 s_idled_cycles;
static u32 s_fake_dec_start_value;
static u64 s_fake_dec_start_ticks;

// Are we in a function that has been called from Advance()
static bool s_is_global_timer_sane;

s64 g_global_timer;
u64 g_fake_TB_start_value;
u64 g_fake_TB_start_ticks;

static EventType* s_ev_lost = nullptr;

static void EmptyTimedCallback(u64 userdata, s64 cyclesLate)
{
}

// Changing the CPU speed in Dolphin isn't actually done by changing the physical clock rate,
// but by changing the amount of work done in a particular amount of time. This tends to be more
// compatible because it stops the games from actually knowing directly that the clock rate has
// changed, and ensures that anything based on waiting a specific number of cycles still works.
//
// Technically it might be more accurate to call this changing the IPC instead of the CPU speed,
// but the effect is largely the same.
static int DowncountToCycles(int downcount)
{
    return static_cast<int>(downcount * g_last_OC_factor_inverted);
}

static int CyclesToDowncount(int cycles)
{
    return static_cast<int>(cycles * s_last_OC_factor);
}

EventType* RegisterEvent(const std::string& name, TimedCallback callback)
{
    // check for existing type with same name.
    // we want event type names to remain unique so that we can use them for serialization.
    _assert_msg_(POWERPC, s_event_types.find(name) == s_event_types.end(),
                 "CoreTiming Event \"%s\" is already registered. Events should only be registered "
                 "during Init to avoid breaking save states.",
                 name.c_str());

    auto info = s_event_types.emplace(name, EventType{callback, nullptr});
    EventType* event_type = &info.first->second;
    event_type->name = &info.first->first;
    return event_type;
}

void UnregisterAllEvents()
{
    _assert_msg_(POWERPC, s_event_queue.empty(), "Cannot unregister events with events pending");
    s_event_types.clear();
}

//.........这里部分代码省略.........

namespace CoreTiming
{

struct EventType
{
	TimedCallback callback;
	std::string name;
};

static std::vector<EventType> event_types;

struct BaseEvent
{
	s64 time;
	u64 userdata;
	int type;
};

typedef LinkedListItem<BaseEvent> Event;

// STATE_TO_SAVE
static Event *first;
static std::mutex tsWriteLock;
static Common::FifoQueue<BaseEvent, false> tsQueue;

// event pools
static Event *eventPool = nullptr;

int slicelength;
static int maxSliceLength = MAX_SLICE_LENGTH;

static s64 globalTimer;
static s64 idledCycles;

static u32 fakeDecStartValue;
static u64 fakeDecStartTicks;
static u64 fakeTBStartValue;
static u64 fakeTBStartTicks;

static int ev_lost;


static void (*advanceCallback)(int cyclesExecuted) = nullptr;

static Event* GetNewEvent()
{
	if (!eventPool)
		return new Event;

	Event* ev = eventPool;
	eventPool = ev->next;
	return ev;
}

static void FreeEvent(Event* ev)
{
	ev->next = eventPool;
	eventPool = ev;
}

static void EmptyTimedCallback(u64 userdata, int cyclesLate) {}

int RegisterEvent(const std::string& name, TimedCallback callback)
{
	EventType type;
	type.name = name;
	type.callback = callback;

	// check for existing type with same name.
	// we want event type names to remain unique so that we can use them for serialization.
	for (auto& event_type : event_types)
	{
		if (name == event_type.name)
		{
			WARN_LOG(POWERPC, "Discarded old event type \"%s\" because a new type with the same name was registered.", name.c_str());
			// we don't know if someone might be holding on to the type index,
			// so we gut the old event type instead of actually removing it.
			event_type.name = "_discarded_event";
			event_type.callback = &EmptyTimedCallback;
		}
	}

	event_types.push_back(type);
	return (int)event_types.size() - 1;
}

void UnregisterAllEvents()
{
	if (first)
		PanicAlertT("Cannot unregister events with events pending");
	event_types.clear();
}

void Init()
{
	PowerPC::ppcState.downcount = maxSliceLength;
	slicelength = maxSliceLength;
	globalTimer = 0;
	idledCycles = 0;

//.........这里部分代码省略.........

namespace CoreTiming
{

struct EventType
{
	TimedCallback callback;
	std::string name;
};

static std::vector<EventType> event_types;

struct BaseEvent
{
	s64 time;
	u64 userdata;
	int type;
};

typedef LinkedListItem<BaseEvent> Event;

// STATE_TO_SAVE
static Event *first;
static std::mutex tsWriteLock;
static Common::FifoQueue<BaseEvent, false> tsQueue;

// event pools
static Event *eventPool = nullptr;

static float s_lastOCFactor;
float g_lastOCFactor_inverted;
int g_slicelength;
static int maxslicelength = MAX_SLICE_LENGTH;

static s64 idledCycles;
static u32 fakeDecStartValue;
static u64 fakeDecStartTicks;

// Are we in a function that has been called from Advance()
static bool globalTimerIsSane;

s64 g_globalTimer;
u64 g_fakeTBStartValue;
u64 g_fakeTBStartTicks;

static int ev_lost;

static Event* GetNewEvent()
{
	if (!eventPool)
		return new Event;

	Event* ev = eventPool;
	eventPool = ev->next;
	return ev;
}

static void FreeEvent(Event* ev)
{
	ev->next = eventPool;
	eventPool = ev;
}

static void EmptyTimedCallback(u64 userdata, s64 cyclesLate) {}

// Changing the CPU speed in Dolphin isn't actually done by changing the physical clock rate,
// but by changing the amount of work done in a particular amount of time. This tends to be more
// compatible because it stops the games from actually knowing directly that the clock rate has
// changed, and ensures that anything based on waiting a specific number of cycles still works.
//
// Technically it might be more accurate to call this changing the IPC instead of the CPU speed,
// but the effect is largely the same.
static int DowncountToCycles(int downcount)
{
	return (int)(downcount * g_lastOCFactor_inverted);
}

static int CyclesToDowncount(int cycles)
{
	return (int)(cycles * s_lastOCFactor);
}

int RegisterEvent(const std::string& name, TimedCallback callback)
{
	EventType type;
	type.name = name;
	type.callback = callback;

	// check for existing type with same name.
	// we want event type names to remain unique so that we can use them for serialization.
	for (auto& event_type : event_types)
	{
		if (name == event_type.name)
		{
			WARN_LOG(POWERPC, "Discarded old event type \"%s\" because a new type with the same name was registered.", name.c_str());
			// we don't know if someone might be holding on to the type index,
			// so we gut the old event type instead of actually removing it.
			event_type.name = "_discarded_event";
			event_type.callback = &EmptyTimedCallback;
		}
	}
//.........这里部分代码省略.........

// This is to be called when outside threads, such as the graphics thread, wants to
// schedule things to be executed on the main thread.
void ScheduleEvent_Threadsafe(int cyclesIntoFuture, int event_type, u64 userdata)
{
	std::lock_guard<std::mutex> lk(tsWriteLock);
	Event ne;
	ne.time = globalTimer + cyclesIntoFuture;
	ne.type = event_type;
	ne.userdata = userdata;
	tsQueue.Push(ne);
}

void MoveEvents()
{
    for (Event ev; s_ts_queue.Pop(ev);)
    {
        ev.fifo_order = s_event_fifo_id++;
        s_event_queue.emplace_back(std::move(ev));
        std::push_heap(s_event_queue.begin(), s_event_queue.end(), std::greater<Event>());
    }
}

void MoveEvents()
{
	BaseEvent sevt;
	while (tsQueue.Pop(sevt))
	{
		Event *evt = GetNewEvent();
		evt->time = sevt.time;
		evt->userdata = sevt.userdata;
		evt->type = sevt.type;
		AddEventToQueue(evt);
	}
}

// This is to be called when outside threads, such as the graphics thread, wants to
// schedule things to be executed on the main thread.
void ScheduleEvent_Threadsafe(s64 cyclesIntoFuture, int event_type, u64 userdata)
{
	_assert_msg_(POWERPC, !Core::IsCPUThread(), "ScheduleEvent_Threadsafe from wrong thread");
	if (Core::g_want_determinism)
	{
		ERROR_LOG(POWERPC, "Someone scheduled an off-thread \"%s\" event while netplay or movie play/record "
		                   "was active.  This is likely to cause a desync.",
		                   event_types[event_type].name.c_str());
	}
	std::lock_guard<std::mutex> lk(tsWriteLock);
	Event ne;
	ne.time = g_globalTimer + cyclesIntoFuture;
	ne.type = event_type;
	ne.userdata = userdata;
	tsQueue.Push(ne);
}

void ScheduleEvent(s64 cycles_into_future, EventType* event_type, u64 userdata, FromThread from)
{
    _assert_msg_(POWERPC, event_type, "Event type is nullptr, will crash now.");

    bool from_cpu_thread;
    if (from == FromThread::ANY)
    {
        from_cpu_thread = Core::IsCPUThread();
    }
    else
    {
        from_cpu_thread = from == FromThread::CPU;
        _assert_msg_(POWERPC, from_cpu_thread == Core::IsCPUThread(),
                     "ScheduleEvent from wrong thread (%s)", from_cpu_thread ? "CPU" : "non-CPU");
    }

    if (from_cpu_thread)
    {
        s64 timeout = GetTicks() + cycles_into_future;

        // If this event needs to be scheduled before the next advance(), force one early
        if (!s_is_global_timer_sane)
            ForceExceptionCheck(cycles_into_future);

        s_event_queue.emplace_back(Event{timeout, s_event_fifo_id++, userdata, event_type});
        std::push_heap(s_event_queue.begin(), s_event_queue.end(), std::greater<Event>());
    }
    else
    {
        if (Core::g_want_determinism)
        {
            ERROR_LOG(POWERPC, "Someone scheduled an off-thread \"%s\" event while netplay or "
                      "movie play/record was active.  This is likely to cause a desync.",
                      event_type->name->c_str());
        }

        std::lock_guard<std::mutex> lk(s_ts_write_lock);
        s_ts_queue.Push(Event{g_global_timer + cycles_into_future, 0, userdata, event_type});
    }
}