[IE][VPU][XLink]: XLink semaphore wrappers impl (#3079)

XLink wrappers for POSIX semaphore functions (refer sem_overview for details). In the description of standard sem_destroy the following is noted:
"Destroying a semaphore that other processes or threads are currently blocked on (in sem_wait(3)) produces undefined behavior."
XLink wrappers use thread-safe reference count and destroy the semaphore only in case if there are no waiters.

* XLink semaphore wrapper impl
* Extend XLink win_synchapi

inference-engine/thirdparty/movidius/XLink/pc/Win/include/win_synchapi.h

@@ -12,6 +12,8 @@
 extern "C" {
 #endif
 
+#define PTHREAD_COND_INITIALIZER {0}
+
 typedef struct _pthread_condattr_t pthread_condattr_t;
 
 typedef struct
@@ -23,9 +25,13 @@ pthread_cond_t;
 int pthread_cond_init(pthread_cond_t* __cond, const pthread_condattr_t* __cond_attr);
 int pthread_cond_destroy(pthread_cond_t* __cond);
 
+int pthread_cond_wait(pthread_cond_t *__cond,
+    pthread_mutex_t *__mutex);
 int pthread_cond_timedwait(pthread_cond_t* __cond,
     pthread_mutex_t* __mutex,
     const struct timespec* __abstime);
+
+int pthread_cond_signal(pthread_cond_t* __cond);
 int pthread_cond_broadcast(pthread_cond_t* __cond);
 
 #ifdef __cplusplus

inference-engine/thirdparty/movidius/XLink/pc/Win/src/win_synchapi.c

@@ -21,9 +21,17 @@ int pthread_cond_destroy(pthread_cond_t* __cond)
     return 0;
 }
 
+int pthread_cond_wait(pthread_cond_t *__cond,
+    pthread_mutex_t *__mutex)
+{
+    if (__cond == NULL || __mutex == NULL)
+        return ERROR_INVALID_HANDLE;
+    return pthread_cond_timedwait(__cond, __mutex, NULL);
+}
+
 int pthread_cond_timedwait(pthread_cond_t* __cond,
     pthread_mutex_t* __mutex,
-    const struct timespec* __abstime) 
+    const struct timespec* __abstime)
 {
     if (__cond == NULL) {
         return ERROR_INVALID_HANDLE;
@@ -42,7 +50,7 @@ int pthread_cond_timedwait(pthread_cond_t* __cond,
     return rc == ERROR_TIMEOUT ? ETIMEDOUT : rc;
 }
 
-int pthread_cond_broadcast(pthread_cond_t *__cond)
+int pthread_cond_signal(pthread_cond_t *__cond)
 {
     if (__cond == NULL) {
         return ERROR_INVALID_HANDLE;
@@ -51,3 +59,13 @@ int pthread_cond_broadcast(pthread_cond_t *__cond)
     WakeConditionVariable(&__cond->_cv);
     return 0;
 }
+
+int pthread_cond_broadcast(pthread_cond_t *__cond)
+{
+    if (__cond == NULL) {
+        return ERROR_INVALID_HANDLE;
+    }
+
+    WakeAllConditionVariable(&__cond->_cv);
+    return 0;
+}

inference-engine/thirdparty/movidius/XLink/shared/include/XLinkPrivateDefines.h

@@ -57,7 +57,7 @@ typedef struct xLinkDesc_t {
     xLinkState_t peerState;
     xLinkDeviceHandle_t deviceHandle;
     linkId_t id;
-    sem_t dispatcherClosedSem;
+    XLink_sem_t dispatcherClosedSem;
 
     //Deprecated fields. Begin.
     int hostClosedFD;

inference-engine/thirdparty/movidius/XLink/shared/include/XLinkSemaphore.h

@@ -0,0 +1,74 @@
+// Copyright (C) 2020 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+
+///
+/// @file
+///
+/// @brief     Application configuration Leon header
+///
+
+#ifndef _XLINKSEMAPHORE_H
+#define _XLINKSEMAPHORE_H
+
+# if (defined(_WIN32) || defined(_WIN64))
+#  include "win_pthread.h"
+#  include "win_semaphore.h"
+#  include "win_synchapi.h"
+# else
+#  include <pthread.h>
+#  ifdef __APPLE__
+#   include "pthread_semaphore.h"
+#  else
+#   include <semaphore.h>
+# endif
+# endif
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+//
+// This structure describes the semaphore used in XLink and
+// extends the standard semaphore with a reference count.
+// The counter is thread-safe and changes only in cases if
+// all tools of thread synchronization are really unlocked.
+// refs == -1 in case if semaphore was destroyed;
+// refs == 0 in case if semaphore was initialized but has no waiters;
+// refs == N in case if there are N waiters which called sem_wait().
+//
+
+typedef struct {
+    sem_t psem;
+    int refs;
+} XLink_sem_t;
+
+//
+// XLink wrappers for POSIX semaphore functions (refer sem_overview for details)
+// In description of standard sem_destroy the following can be noted:
+// "Destroying a semaphore that other processes or threads are currently
+// blocked on (in sem_wait(3)) produces undefined behavior."
+// XLink wrappers use thread-safe reference count and destroy the semaphore only in case
+// if there are no waiters
+//
+
+int XLink_sem_init(XLink_sem_t* sem, int pshared, unsigned int value);
+int XLink_sem_destroy(XLink_sem_t* sem);
+int XLink_sem_post(XLink_sem_t* sem);
+int XLink_sem_wait(XLink_sem_t* sem);
+int XLink_sem_timedwait(XLink_sem_t* sem, const struct timespec* abstime);
+
+//
+// Helper functions for XLink semaphore wrappers.
+// Use them only in case if you know what you are doing.
+//
+
+int XLink_sem_set_refs(XLink_sem_t* sem, int refs);
+int XLink_sem_get_refs(XLink_sem_t* sem, int *sval);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // _XLINKSEMAPHORE_H

inference-engine/thirdparty/movidius/XLink/shared/include/XLinkStream.h

@@ -6,16 +6,7 @@
 #define _XLINKSTREAM_H
 
 #include "XLinkPublicDefines.h"
-
-# if (defined(_WIN32) || defined(_WIN64))
-#  include "win_semaphore.h"
-# else
-#  ifdef __APPLE__
-#   include "pthread_semaphore.h"
-#  else
-#   include <semaphore.h>
-# endif
-# endif
+#include "XLinkSemaphore.h"
 
 /**
  * @brief Streams opened to device
@@ -40,7 +31,7 @@ typedef struct{
 
     uint32_t closeStreamInitiated;
 
-    sem_t sem;
+    XLink_sem_t sem;
 }streamDesc_t;
 
 XLinkError_t XLinkStreamInitialize(

inference-engine/thirdparty/movidius/XLink/shared/src/XLinkDevice.c

@@ -253,7 +253,7 @@ XLinkError_t XLinkResetRemote(linkId_t id)
     XLINK_RET_ERR_IF(DispatcherWaitEventComplete(&link->deviceHandle),
         X_LINK_TIMEOUT);
 
-    if(sem_wait(&link->dispatcherClosedSem)) {
+    if(XLink_sem_wait(&link->dispatcherClosedSem)) {
         mvLog(MVLOG_ERROR,"can't wait dispatcherClosedSem\n");
         return X_LINK_ERROR;
     }
@@ -390,7 +390,7 @@ static xLinkDesc_t* getNextAvailableLink() {
 
     xLinkDesc_t* link = &availableXLinks[i];
 
-    if (sem_init(&link->dispatcherClosedSem, 0 ,0)) {
+    if (XLink_sem_init(&link->dispatcherClosedSem, 0 ,0)) {
         mvLog(MVLOG_ERROR, "Cannot initialize semaphore\n");
         return NULL;
     }