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wait.cpp

00001 // wait.cpp - written and placed in the public domain by Wei Dai
00002 
00003 #include "pch.h"
00004 #include "wait.h"
00005 #include "misc.h"
00006 
00007 #ifdef SOCKETS_AVAILABLE
00008 
00009 #ifdef USE_BERKELEY_STYLE_SOCKETS
00010 #include <errno.h>
00011 #include <sys/types.h>
00012 #include <sys/time.h>
00013 #include <unistd.h>
00014 #endif
00015 
00016 #define TRACE_WAIT 0
00017 
00018 #if TRACE_WAIT
00019 #include "hrtimer.h"
00020 #endif
00021 
00022 NAMESPACE_BEGIN(CryptoPP)
00023 
00024 unsigned int WaitObjectContainer::MaxWaitObjects()
00025 {
00026 #ifdef USE_WINDOWS_STYLE_SOCKETS
00027         return MAXIMUM_WAIT_OBJECTS * (MAXIMUM_WAIT_OBJECTS-1);
00028 #else
00029         return FD_SETSIZE;
00030 #endif
00031 }
00032 
00033 WaitObjectContainer::WaitObjectContainer()
00034 #if CRYPTOPP_DETECT_NO_WAIT
00035         : m_sameResultCount(0), m_timer(Timer::MILLISECONDS)
00036 #endif
00037 {
00038         Clear();
00039 }
00040 
00041 void WaitObjectContainer::Clear()
00042 {
00043 #ifdef USE_WINDOWS_STYLE_SOCKETS
00044         m_handles.clear();
00045 #else
00046         m_maxFd = 0;
00047         FD_ZERO(&m_readfds);
00048         FD_ZERO(&m_writefds);
00049 #endif
00050         m_noWait = false;
00051 }
00052 
00053 void WaitObjectContainer::SetNoWait()
00054 {
00055 #if CRYPTOPP_DETECT_NO_WAIT
00056         if (-1 == m_lastResult && m_timer.ElapsedTime() > 1000)
00057         {
00058                 if (m_sameResultCount > m_timer.ElapsedTime())
00059                         try {throw 0;} catch (...) {}   // possible no-wait loop, break in debugger
00060                 m_timer.StartTimer();
00061         }
00062 #endif
00063         m_noWait = true;
00064 }
00065 
00066 #ifdef USE_WINDOWS_STYLE_SOCKETS
00067 
00068 struct WaitingThreadData
00069 {
00070         bool waitingToWait, terminate;
00071         HANDLE startWaiting, stopWaiting;
00072         const HANDLE *waitHandles;
00073         unsigned int count;
00074         HANDLE threadHandle;
00075         DWORD threadId;
00076         DWORD* error;
00077 };
00078 
00079 WaitObjectContainer::~WaitObjectContainer()
00080 {
00081         try             // don't let exceptions escape destructor
00082         {
00083                 if (!m_threads.empty())
00084                 {
00085                         HANDLE threadHandles[MAXIMUM_WAIT_OBJECTS];
00086                         unsigned int i;
00087                         for (i=0; i<m_threads.size(); i++)
00088                         {
00089                                 WaitingThreadData &thread = *m_threads[i];
00090                                 while (!thread.waitingToWait)   // spin until thread is in the initial "waiting to wait" state
00091                                         Sleep(0);
00092                                 thread.terminate = true;
00093                                 threadHandles[i] = thread.threadHandle;
00094                         }
00095                         PulseEvent(m_startWaiting);
00096                         ::WaitForMultipleObjects(m_threads.size(), threadHandles, TRUE, INFINITE);
00097                         for (i=0; i<m_threads.size(); i++)
00098                                 CloseHandle(threadHandles[i]);
00099                         CloseHandle(m_startWaiting);
00100                         CloseHandle(m_stopWaiting);
00101                 }
00102         }
00103         catch (...)
00104         {
00105         }
00106 }
00107 
00108 
00109 void WaitObjectContainer::AddHandle(HANDLE handle)
00110 {
00111 #if CRYPTOPP_DETECT_NO_WAIT
00112         if (m_handles.size() == m_lastResult && m_timer.ElapsedTime() > 1000)
00113         {
00114                 if (m_sameResultCount > m_timer.ElapsedTime())
00115                         try {throw 0;} catch (...) {}   // possible no-wait loop, break in debugger
00116                 m_timer.StartTimer();
00117         }
00118 #endif
00119         m_handles.push_back(handle);
00120 }
00121 
00122 DWORD WINAPI WaitingThread(LPVOID lParam)
00123 {
00124         std::auto_ptr<WaitingThreadData> pThread((WaitingThreadData *)lParam);
00125         WaitingThreadData &thread = *pThread;
00126         std::vector<HANDLE> handles;
00127 
00128         while (true)
00129         {
00130                 thread.waitingToWait = true;
00131                 ::WaitForSingleObject(thread.startWaiting, INFINITE);
00132                 thread.waitingToWait = false;
00133 
00134                 if (thread.terminate)
00135                         break;
00136                 if (!thread.count)
00137                         continue;
00138 
00139                 handles.resize(thread.count + 1);
00140                 handles[0] = thread.stopWaiting;
00141                 std::copy(thread.waitHandles, thread.waitHandles+thread.count, handles.begin()+1);
00142 
00143                 DWORD result = ::WaitForMultipleObjects(handles.size(), &handles[0], FALSE, INFINITE);
00144 
00145                 if (result == WAIT_OBJECT_0)
00146                         continue;       // another thread finished waiting first, so do nothing
00147                 SetEvent(thread.stopWaiting);
00148                 if (!(result > WAIT_OBJECT_0 && result < WAIT_OBJECT_0 + handles.size()))
00149                 {
00150                         assert(!"error in WaitingThread");      // break here so we can see which thread has an error
00151                         *thread.error = ::GetLastError();
00152                 }
00153         }
00154 
00155         return S_OK;    // return a value here to avoid compiler warning
00156 }
00157 
00158 void WaitObjectContainer::CreateThreads(unsigned int count)
00159 {
00160         unsigned int currentCount = m_threads.size();
00161         if (currentCount == 0)
00162         {
00163                 m_startWaiting = ::CreateEvent(NULL, TRUE, FALSE, NULL);
00164                 m_stopWaiting = ::CreateEvent(NULL, TRUE, FALSE, NULL);
00165         }
00166 
00167         if (currentCount < count)
00168         {
00169                 m_threads.resize(count);
00170                 for (unsigned int i=currentCount; i<count; i++)
00171                 {
00172                         m_threads[i] = new WaitingThreadData;
00173                         WaitingThreadData &thread = *m_threads[i];
00174                         thread.terminate = false;
00175                         thread.startWaiting = m_startWaiting;
00176                         thread.stopWaiting = m_stopWaiting;
00177                         thread.waitingToWait = false;
00178                         thread.threadHandle = CreateThread(NULL, 0, &WaitingThread, &thread, 0, &thread.threadId);
00179                 }
00180         }
00181 }
00182 
00183 bool WaitObjectContainer::Wait(unsigned long milliseconds)
00184 {
00185         if (m_noWait || m_handles.empty())
00186         {
00187 #if CRYPTOPP_DETECT_NO_WAIT
00188                 if (-1 == m_lastResult)
00189                         m_sameResultCount++;
00190                 else
00191                 {
00192                         m_lastResult = -1;
00193                         m_sameResultCount = 0;
00194                 }
00195 #endif
00196                 return true;
00197         }
00198 
00199         if (m_handles.size() > MAXIMUM_WAIT_OBJECTS)
00200         {
00201                 // too many wait objects for a single WaitForMultipleObjects call, so use multiple threads
00202                 static const unsigned int WAIT_OBJECTS_PER_THREAD = MAXIMUM_WAIT_OBJECTS-1;
00203                 unsigned int nThreads = (m_handles.size() + WAIT_OBJECTS_PER_THREAD - 1) / WAIT_OBJECTS_PER_THREAD;
00204                 if (nThreads > MAXIMUM_WAIT_OBJECTS)    // still too many wait objects, maybe implement recursive threading later?
00205                         throw Err("WaitObjectContainer: number of wait objects exceeds limit");
00206                 CreateThreads(nThreads);
00207                 DWORD error = S_OK;
00208                 
00209                 for (unsigned int i=0; i<m_threads.size(); i++)
00210                 {
00211                         WaitingThreadData &thread = *m_threads[i];
00212                         while (!thread.waitingToWait)   // spin until thread is in the initial "waiting to wait" state
00213                                 Sleep(0);
00214                         if (i<nThreads)
00215                         {
00216                                 thread.waitHandles = &m_handles[i*WAIT_OBJECTS_PER_THREAD];
00217                                 thread.count = STDMIN(WAIT_OBJECTS_PER_THREAD, m_handles.size() - i*WAIT_OBJECTS_PER_THREAD);
00218                                 thread.error = &error;
00219                         }
00220                         else
00221                                 thread.count = 0;
00222                 }
00223 
00224                 ResetEvent(m_stopWaiting);
00225                 PulseEvent(m_startWaiting);
00226 
00227                 DWORD result = ::WaitForSingleObject(m_stopWaiting, milliseconds);
00228                 if (result == WAIT_OBJECT_0)
00229                 {
00230                         if (error == S_OK)
00231                                 return true;
00232                         else
00233                                 throw Err("WaitObjectContainer: WaitForMultipleObjects failed with error " + IntToString(error));
00234                 }
00235                 SetEvent(m_stopWaiting);
00236                 if (result == WAIT_TIMEOUT)
00237                         return false;
00238                 else
00239                         throw Err("WaitObjectContainer: WaitForSingleObject failed with error " + IntToString(::GetLastError()));
00240         }
00241         else
00242         {
00243 #if TRACE_WAIT
00244                 static Timer t(Timer::MICROSECONDS);
00245                 static unsigned long lastTime = 0;
00246                 unsigned long timeBeforeWait = t.ElapsedTime();
00247 #endif
00248                 DWORD result = ::WaitForMultipleObjects(m_handles.size(), &m_handles[0], FALSE, milliseconds);
00249 #if TRACE_WAIT
00250                 if (milliseconds > 0)
00251                 {
00252                         unsigned long timeAfterWait = t.ElapsedTime();
00253                         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());
00254                         lastTime = timeAfterWait;
00255                 }
00256 #endif
00257                 if (result >= WAIT_OBJECT_0 && result < WAIT_OBJECT_0 + m_handles.size())
00258                 {
00259 #if CRYPTOPP_DETECT_NO_WAIT
00260                         if (result == m_lastResult)
00261                                 m_sameResultCount++;
00262                         else
00263                         {
00264                                 m_lastResult = result;
00265                                 m_sameResultCount = 0;
00266                         }
00267 #endif
00268                         return true;
00269                 }
00270                 else if (result == WAIT_TIMEOUT)
00271                         return false;
00272                 else
00273                         throw Err("WaitObjectContainer: WaitForMultipleObjects failed with error " + IntToString(::GetLastError()));
00274         }
00275 }
00276 
00277 #else
00278 
00279 void WaitObjectContainer::AddReadFd(int fd)
00280 {
00281         FD_SET(fd, &m_readfds);
00282         m_maxFd = STDMAX(m_maxFd, fd);
00283 }
00284 
00285 void WaitObjectContainer::AddWriteFd(int fd)
00286 {
00287         FD_SET(fd, &m_writefds);
00288         m_maxFd = STDMAX(m_maxFd, fd);
00289 }
00290 
00291 bool WaitObjectContainer::Wait(unsigned long milliseconds)
00292 {
00293         if (m_noWait || m_maxFd == 0)
00294                 return true;
00295 
00296         timeval tv, *timeout;
00297 
00298         if (milliseconds == INFINITE_TIME)
00299                 timeout = NULL;
00300         else
00301         {
00302                 tv.tv_sec = milliseconds / 1000;
00303                 tv.tv_usec = (milliseconds % 1000) * 1000;
00304                 timeout = &tv;
00305         }
00306 
00307         int result = select(m_maxFd+1, &m_readfds, &m_writefds, NULL, timeout);
00308 
00309         if (result > 0)
00310                 return true;
00311         else if (result == 0)
00312                 return false;
00313         else
00314                 throw Err("WaitObjectContainer: select failed with error " + errno);
00315 }
00316 
00317 #endif
00318 
00319 // ********************************************************
00320 
00321 bool Waitable::Wait(unsigned long milliseconds)
00322 {
00323         WaitObjectContainer container;
00324         GetWaitObjects(container);
00325         return container.Wait(milliseconds);
00326 }
00327 
00328 NAMESPACE_END
00329 
00330 #endif

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