// wait.cpp - written and placed in the public domain by Wei Dai
#include "pch.h"
#include "wait.h"
#include "misc.h"
#ifdef SOCKETS_AVAILABLE
#ifdef USE_BERKELEY_STYLE_SOCKETS
#include <errno.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#endif
NAMESPACE_BEGIN(CryptoPP)
unsigned int WaitObjectContainer::MaxWaitObjects()
{
#ifdef USE_WINDOWS_STYLE_SOCKETS
return MAXIMUM_WAIT_OBJECTS * (MAXIMUM_WAIT_OBJECTS-1);
#else
return FD_SETSIZE;
#endif
}
WaitObjectContainer::WaitObjectContainer(WaitObjectsTracer* tracer)
: m_tracer(tracer), m_eventTimer(Timer::MILLISECONDS)
, m_sameResultCount(0), m_noWaitTimer(Timer::MILLISECONDS)
{
Clear();
m_eventTimer.StartTimer();
}
void WaitObjectContainer::Clear()
{
#ifdef USE_WINDOWS_STYLE_SOCKETS
m_handles.clear();
#else
m_maxFd = 0;
FD_ZERO(&m_readfds);
FD_ZERO(&m_writefds);
#endif
m_noWait = false;
m_firstEventTime = 0;
}
inline void WaitObjectContainer::SetLastResult(LastResultType result)
{
if (result == m_lastResult)
m_sameResultCount++;
else
{
m_lastResult = result;
m_sameResultCount = 0;
}
}
void WaitObjectContainer::DetectNoWait(LastResultType result, CallStack const& callStack)
{
if (result == m_lastResult && m_noWaitTimer.ElapsedTime() > 1000)
{
if (m_sameResultCount > m_noWaitTimer.ElapsedTime())
{
if (m_tracer)
{
std::string desc = "No wait loop detected - m_lastResult: ";
desc.append(IntToString(m_lastResult)).append(", call stack:");
for (CallStack const* cs = &callStack; cs; cs = cs->Prev())
desc.append("\n- ").append(cs->Format());
m_tracer->TraceNoWaitLoop(desc);
}
try { throw 0; } catch (...) {} // help debugger break
}
m_noWaitTimer.StartTimer();
m_sameResultCount = 0;
}
}
void WaitObjectContainer::SetNoWait(CallStack const& callStack)
{
DetectNoWait(LASTRESULT_NOWAIT, CallStack("WaitObjectContainer::SetNoWait()", &callStack));
m_noWait = true;
}
void WaitObjectContainer::ScheduleEvent(double milliseconds, CallStack const& callStack)
{
if (milliseconds <= 3)
DetectNoWait(LASTRESULT_SCHEDULED, CallStack("WaitObjectContainer::ScheduleEvent()", &callStack));
double thisEventTime = m_eventTimer.ElapsedTimeAsDouble() + milliseconds;
if (!m_firstEventTime || thisEventTime < m_firstEventTime)
m_firstEventTime = thisEventTime;
}
#ifdef USE_WINDOWS_STYLE_SOCKETS
struct WaitingThreadData
{
bool waitingToWait, terminate;
HANDLE startWaiting, stopWaiting;
const HANDLE *waitHandles;
unsigned int count;
HANDLE threadHandle;
DWORD threadId;
DWORD* error;
};
WaitObjectContainer::~WaitObjectContainer()
{
try // don't let exceptions escape destructor
{
if (!m_threads.empty())
{
HANDLE threadHandles[MAXIMUM_WAIT_OBJECTS];
unsigned int i;
for (i=0; i<m_threads.size(); i++)
{
WaitingThreadData &thread = *m_threads[i];
while (!thread.waitingToWait) // spin until thread is in the initial "waiting to wait" state
Sleep(0);
thread.terminate = true;
threadHandles[i] = thread.threadHandle;
}
PulseEvent(m_startWaiting);
::WaitForMultipleObjects((DWORD)m_threads.size(), threadHandles, TRUE, INFINITE);
for (i=0; i<m_threads.size(); i++)
CloseHandle(threadHandles[i]);
CloseHandle(m_startWaiting);
CloseHandle(m_stopWaiting);
}
}
catch (...)
{
}
}
void WaitObjectContainer::AddHandle(HANDLE handle, CallStack const& callStack)
{
DetectNoWait(m_handles.size(), CallStack("WaitObjectContainer::AddHandle()", &callStack));
m_handles.push_back(handle);
}
DWORD WINAPI WaitingThread(LPVOID lParam)
{
std::auto_ptr<WaitingThreadData> pThread((WaitingThreadData *)lParam);
WaitingThreadData &thread = *pThread;
std::vector<HANDLE> handles;
while (true)
{
thread.waitingToWait = true;
::WaitForSingleObject(thread.startWaiting, INFINITE);
thread.waitingToWait = false;
if (thread.terminate)
break;
if (!thread.count)
continue;
handles.resize(thread.count + 1);
handles[0] = thread.stopWaiting;
std::copy(thread.waitHandles, thread.waitHandles+thread.count, handles.begin()+1);
DWORD result = ::WaitForMultipleObjects((DWORD)handles.size(), &handles[0], FALSE, INFINITE);
if (result == WAIT_OBJECT_0)
continue; // another thread finished waiting first, so do nothing
SetEvent(thread.stopWaiting);
if (!(result > WAIT_OBJECT_0 && result < WAIT_OBJECT_0 + handles.size()))
{
assert(!"error in WaitingThread"); // break here so we can see which thread has an error
*thread.error = ::GetLastError();
}
}
return S_OK; // return a value here to avoid compiler warning
}
void WaitObjectContainer::CreateThreads(unsigned int count)
{
size_t currentCount = m_threads.size();
if (currentCount == 0)
{
m_startWaiting = ::CreateEvent(NULL, TRUE, FALSE, NULL);
m_stopWaiting = ::CreateEvent(NULL, TRUE, FALSE, NULL);
}
if (currentCount < count)
{
m_threads.resize(count);
for (size_t i=currentCount; i<count; i++)
{
m_threads[i] = new WaitingThreadData;
WaitingThreadData &thread = *m_threads[i];
thread.terminate = false;
thread.startWaiting = m_startWaiting;
thread.stopWaiting = m_stopWaiting;
thread.waitingToWait = false;
thread.threadHandle = CreateThread(NULL, 0, &WaitingThread, &thread, 0, &thread.threadId);
}
}
}
bool WaitObjectContainer::Wait(unsigned long milliseconds)
{
if (m_noWait || (m_handles.empty() && !m_firstEventTime))
{
SetLastResult(LASTRESULT_NOWAIT);
return true;
}
bool timeoutIsScheduledEvent = false;
if (m_firstEventTime)
{
double timeToFirstEvent = SaturatingSubtract(m_firstEventTime, m_eventTimer.ElapsedTimeAsDouble());
if (timeToFirstEvent <= milliseconds)
{
milliseconds = (unsigned long)timeToFirstEvent;
timeoutIsScheduledEvent = true;
}
if (m_handles.empty() || !milliseconds)
{
if (milliseconds)
Sleep(milliseconds);
SetLastResult(timeoutIsScheduledEvent ? LASTRESULT_SCHEDULED : LASTRESULT_TIMEOUT);
return timeoutIsScheduledEvent;
}
}
if (m_handles.size() > MAXIMUM_WAIT_OBJECTS)
{
// too many wait objects for a single WaitForMultipleObjects call, so use multiple threads
static const unsigned int WAIT_OBJECTS_PER_THREAD = MAXIMUM_WAIT_OBJECTS-1;
unsigned int nThreads = (unsigned int)((m_handles.size() + WAIT_OBJECTS_PER_THREAD - 1) / WAIT_OBJECTS_PER_THREAD);
if (nThreads > MAXIMUM_WAIT_OBJECTS) // still too many wait objects, maybe implement recursive threading later?
throw Err("WaitObjectContainer: number of wait objects exceeds limit");
CreateThreads(nThreads);
DWORD error = S_OK;
for (unsigned int i=0; i<m_threads.size(); i++)
{
WaitingThreadData &thread = *m_threads[i];
while (!thread.waitingToWait) // spin until thread is in the initial "waiting to wait" state
Sleep(0);
if (i<nThreads)
{
thread.waitHandles = &m_handles[i*WAIT_OBJECTS_PER_THREAD];
thread.count = UnsignedMin(WAIT_OBJECTS_PER_THREAD, m_handles.size() - i*WAIT_OBJECTS_PER_THREAD);
thread.error = &error;
}
else
thread.count = 0;
}
ResetEvent(m_stopWaiting);
PulseEvent(m_startWaiting);
DWORD result = ::WaitForSingleObject(m_stopWaiting, milliseconds);
if (result == WAIT_OBJECT_0)
{
if (error == S_OK)
return true;
else
throw Err("WaitObjectContainer: WaitForMultipleObjects in thread failed with error " + IntToString(error));
}
SetEvent(m_stopWaiting);
if (result == WAIT_TIMEOUT)
{
SetLastResult(timeoutIsScheduledEvent ? LASTRESULT_SCHEDULED : LASTRESULT_TIMEOUT);
return timeoutIsScheduledEvent;
}
else
throw Err("WaitObjectContainer: WaitForSingleObject failed with error " + IntToString(::GetLastError()));
}
else
{
#if TRACE_WAIT
static Timer t(Timer::MICROSECONDS);
static unsigned long lastTime = 0;
unsigned long timeBeforeWait = t.ElapsedTime();
#endif
DWORD result = ::WaitForMultipleObjects((DWORD)m_handles.size(), &m_handles[0], FALSE, milliseconds);
#if TRACE_WAIT
if (milliseconds > 0)
{
unsigned long timeAfterWait = t.ElapsedTime();
OutputDebugString(("Handles " + IntToString(m_handles.size()) + ", Woke up by " + IntToString(result-WAIT_OBJECT_0) + ", Busied for " + IntToString(timeBeforeWait-lastTime) + " us, Waited for " + IntToString(timeAfterWait-timeBeforeWait) + " us, max " + IntToString(milliseconds) + "ms\n").c_str());
lastTime = timeAfterWait;
}
#endif
if (result >= WAIT_OBJECT_0 && result < WAIT_OBJECT_0 + m_handles.size())
{
if (result == m_lastResult)
m_sameResultCount++;
else
{
m_lastResult = result;
m_sameResultCount = 0;
}
return true;
}
else if (result == WAIT_TIMEOUT)
{
SetLastResult(timeoutIsScheduledEvent ? LASTRESULT_SCHEDULED : LASTRESULT_TIMEOUT);
return timeoutIsScheduledEvent;
}
else
throw Err("WaitObjectContainer: WaitForMultipleObjects failed with error " + IntToString(::GetLastError()));
}
}
#else // #ifdef USE_WINDOWS_STYLE_SOCKETS
void WaitObjectContainer::AddReadFd(int fd, CallStack const& callStack) // TODO: do something with callStack
{
FD_SET(fd, &m_readfds);
m_maxFd = STDMAX(m_maxFd, fd);
}
void WaitObjectContainer::AddWriteFd(int fd, CallStack const& callStack) // TODO: do something with callStack
{
FD_SET(fd, &m_writefds);
m_maxFd = STDMAX(m_maxFd, fd);
}
bool WaitObjectContainer::Wait(unsigned long milliseconds)
{
if (m_noWait || (!m_maxFd && !m_firstEventTime))
return true;
bool timeoutIsScheduledEvent = false;
if (m_firstEventTime)
{
double timeToFirstEvent = SaturatingSubtract(m_firstEventTime, m_eventTimer.ElapsedTimeAsDouble());
if (timeToFirstEvent <= milliseconds)
{
milliseconds = (unsigned long)timeToFirstEvent;
timeoutIsScheduledEvent = true;
}
}
timeval tv, *timeout;
if (milliseconds == INFINITE_TIME)
timeout = NULL;
else
{
tv.tv_sec = milliseconds / 1000;
tv.tv_usec = (milliseconds % 1000) * 1000;
timeout = &tv;
}
int result = select(m_maxFd+1, &m_readfds, &m_writefds, NULL, timeout);
if (result > 0)
return true;
else if (result == 0)
return timeoutIsScheduledEvent;
else
throw Err("WaitObjectContainer: select failed with error " + errno);
}
#endif
// ********************************************************
std::string CallStack::Format() const
{
return m_info;
}
std::string CallStackWithNr::Format() const
{
return std::string(m_info) + " / nr: " + IntToString(m_nr);
}
std::string CallStackWithStr::Format() const
{
return std::string(m_info) + " / " + std::string(m_z);
}
bool Waitable::Wait(unsigned long milliseconds, CallStack const& callStack)
{
WaitObjectContainer container;
GetWaitObjects(container, callStack); // reduce clutter by not adding this func to stack
return container.Wait(milliseconds);
}
NAMESPACE_END
#endif
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