1 files changed, 186 insertions, 34 deletions

diff --git a/mysys/my_wincond.c b/mysys/my_wincond.c
index abe339d63b1..64cd67bf8d9 100644
--- a/mysys/my_wincond.c
+++ b/mysys/my_wincond.c
@@ -29,7 +29,92 @@
 #include <process.h>
 #include <sys/timeb.h>
 
-int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
+
+/*
+  Windows native condition variables. We use runtime loading / function 
+  pointers, because they are not available on XP 
+*/
+
+/* Prototypes and function pointers for condition variable functions */
+typedef void (WINAPI * InitializeConditionVariableProc) 
+  (PCONDITION_VARIABLE ConditionVariable);
+
+typedef BOOL (WINAPI * SleepConditionVariableCSProc)
+  (PCONDITION_VARIABLE ConditionVariable,
+  PCRITICAL_SECTION CriticalSection, 
+  DWORD dwMilliseconds);
+
+typedef void (WINAPI * WakeAllConditionVariableProc)
+ (PCONDITION_VARIABLE ConditionVariable);
+
+typedef void (WINAPI * WakeConditionVariableProc)
+  (PCONDITION_VARIABLE ConditionVariable);
+
+static InitializeConditionVariableProc my_InitializeConditionVariable;
+static SleepConditionVariableCSProc my_SleepConditionVariableCS;
+static WakeAllConditionVariableProc my_WakeAllConditionVariable;
+static WakeConditionVariableProc my_WakeConditionVariable;
+
+
+/**
+ Indicates if we have native condition variables,
+ initialized first time pthread_cond_init is called.
+*/
+
+static BOOL have_native_conditions= FALSE;
+
+
+/**
+  Check if native conditions can be used, load function pointers 
+*/
+
+static void check_native_cond_availability(void)
+{
+  HMODULE module= GetModuleHandle("kernel32");
+
+  my_InitializeConditionVariable= (InitializeConditionVariableProc)
+    GetProcAddress(module, "InitializeConditionVariable");
+  my_SleepConditionVariableCS= (SleepConditionVariableCSProc)
+    GetProcAddress(module, "SleepConditionVariableCS");
+  my_WakeAllConditionVariable= (WakeAllConditionVariableProc)
+    GetProcAddress(module, "WakeAllConditionVariable");
+  my_WakeConditionVariable= (WakeConditionVariableProc)
+    GetProcAddress(module, "WakeConditionVariable");
+
+  if (my_InitializeConditionVariable)
+    have_native_conditions= TRUE;
+}
+
+
+
+/**
+  Convert abstime to milliseconds
+*/
+
+static DWORD get_milliseconds(const struct timespec *abstime)
+{
+  struct timespec current_time;
+  long long ms;
+
+  if (abstime == NULL)
+    return INFINITE;
+
+  set_timespec_nsec(current_time, 0);
+  ms= (abstime->tv_sec - current_time.tv_sec)*1000LL +
+    (abstime->tv_nsec - current_time.tv_nsec)/1000000LL;
+  if(ms < 0 )
+    ms= 0;
+  if(ms > UINT_MAX)
+    ms= INFINITE;
+  return (DWORD)ms;
+}
+
+
+/*
+  Old (pre-vista) implementation using events
+*/
+
+static int legacy_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
 {
   cond->waiting= 0;
   InitializeCriticalSection(&cond->lock_waiting);
@@ -58,7 +143,8 @@ int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
   return 0;
 }
 
-int pthread_cond_destroy(pthread_cond_t *cond)
+
+static int legacy_cond_destroy(pthread_cond_t *cond)
 {
   DeleteCriticalSection(&cond->lock_waiting);
 
@@ -70,41 +156,26 @@ int pthread_cond_destroy(pthread_cond_t *cond)
 }
 
 
-int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
-{
-  return pthread_cond_timedwait(cond,mutex,NULL);
-}
-
-
-int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+static int legacy_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
                            struct timespec *abstime)
 {
   int result;
-  long timeout; 
-  union ft64 now;
-
+  DWORD timeout;
+  long long timeout_us;
+  my_hrtime_t now;
+  my_hrtime_t then;
   if( abstime != NULL )
   {
-    GetSystemTimeAsFileTime(&now.ft);
-
-    /*
-      Calculate time left to abstime
-      - subtract start time from current time(values are in 100ns units)
-      - convert to millisec by dividing with 10000
-    */
-    timeout= (long)((abstime->tv.i64 - now.i64) / 10000);
-    
-    /* Don't allow the timeout to be negative */
-    if (timeout < 0)
-      timeout= 0L;
-
-    /*
-      Make sure the calucated timeout does not exceed original timeout
-      value which could cause "wait for ever" if system time changes
-    */
-    if (timeout > abstime->max_timeout_msec)
-      timeout= abstime->max_timeout_msec;
-
+    now= my_hrtime();
+    then.val= 1000000ULL*abstime->tv_sec + abstime->tv_nsec/1000;
+    timeout_us=  then.val - now.val;
+
+    if (timeout_us < 0)
+      timeout= 0;
+    else if (timeout_us > 1000ULL*INFINITE)
+      timeout= INFINITE;
+    else
+      timeout= (DWORD)(timeout_us/1000);
   }
   else
   {
@@ -147,7 +218,7 @@ int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
   return result == WAIT_TIMEOUT ? ETIMEDOUT : 0;
 }
 
-int pthread_cond_signal(pthread_cond_t *cond)
+static int legacy_cond_signal(pthread_cond_t *cond)
 {
   EnterCriticalSection(&cond->lock_waiting);
   
@@ -160,7 +231,7 @@ int pthread_cond_signal(pthread_cond_t *cond)
 }
 
 
-int pthread_cond_broadcast(pthread_cond_t *cond)
+static int legacy_cond_broadcast(pthread_cond_t *cond)
 {
   EnterCriticalSection(&cond->lock_waiting);
   /*
@@ -182,6 +253,87 @@ int pthread_cond_broadcast(pthread_cond_t *cond)
 }
 
 
+/* 
+ Posix API functions. Just choose between native and legacy implementation.
+*/
+
+int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
+{
+  /*
+    Once initialization is used here rather than in my_init(), to 
+    1) avoid  my_init() pitfalls- undefined order in which initialization should
+    run
+    2) be potentially useful C++ (in static constructors that run before main())
+    3) just to simplify the API.
+    Also, the overhead of my_pthread_once is very small.
+  */
+  static my_pthread_once_t once_control= MY_PTHREAD_ONCE_INIT;
+  my_pthread_once(&once_control, check_native_cond_availability);
+
+  if (have_native_conditions)
+  {
+    my_InitializeConditionVariable(&cond->native_cond);
+    return 0;
+  }
+  else 
+    return legacy_cond_init(cond, attr);
+}
+
+
+int pthread_cond_destroy(pthread_cond_t *cond)
+{
+  if (have_native_conditions)
+    return 0; /* no destroy function */
+  else
+    return legacy_cond_destroy(cond);
+}
+
+
+int pthread_cond_broadcast(pthread_cond_t *cond)
+{
+  if (have_native_conditions)
+  {
+    my_WakeAllConditionVariable(&cond->native_cond);
+    return 0;
+  }
+  else
+    return legacy_cond_broadcast(cond);
+}
+
+
+int pthread_cond_signal(pthread_cond_t *cond)
+{
+  if (have_native_conditions)
+  {
+    my_WakeConditionVariable(&cond->native_cond);
+    return 0;
+  }
+  else
+    return legacy_cond_signal(cond);
+}
+
+
+int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+  struct timespec *abstime)
+{
+  if (have_native_conditions)
+  {
+    DWORD timeout= get_milliseconds(abstime);
+    if (!my_SleepConditionVariableCS(&cond->native_cond, mutex, timeout))
+      return ETIMEDOUT;
+    return 0;  
+  }
+  else
+    return legacy_cond_timedwait(cond, mutex, abstime);
+}
+
+
+int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
+{
+  return pthread_cond_timedwait(cond, mutex, NULL);
+}
+
+
 int pthread_attr_init(pthread_attr_t *connect_att)
 {
   connect_att->dwStackSize	= 0;