// bslmt_semaphoreimpl_win32.h -*-C++-*- // ---------------------------------------------------------------------------- // NOTICE // // This component is not up to date with current BDE coding standards, and // should not be used as an example for new development. // ---------------------------------------------------------------------------- #ifndef INCLUDED_BSLMT_SEMAPHOREIMPL_WIN32 #define INCLUDED_BSLMT_SEMAPHOREIMPL_WIN32 #include <bsls_ident.h> BSLS_IDENT("$Id: $") //@PURPOSE: Provide a win32 implementation of 'bslmt::Semaphore'. // //@CLASSES: // bslmt::SemaphoreImpl<Win32Semaphore>: win32 specialization // //@SEE_ALSO: bslmt_semaphore // //@DESCRIPTION: This component provides an implementation of 'bslmt::Semaphore' // for Windows (win32), 'bslmt::SemaphoreImpl<Win32Semaphore>', via the // template specialization: //.. // bslmt::SemaphoreImpl<Platform::Win32Threads> //.. // This template class should not be used (directly) by client code. Clients // should instead use 'bslmt::Semaphore'. // ///Usage ///----- // This component is an implementation detail of 'bslmt' and is *not* intended // for direct client use. It is subject to change without notice. As such, a // usage example is not provided. #include <bslscm_version.h> #include <bslmt_platform.h> #ifdef BSLMT_PLATFORM_WIN32_THREADS // Platform-specific implementation starts here. #include <bsls_atomic.h> #include <bsl_c_limits.h> struct _SECURITY_ATTRIBUTES; typedef struct _SECURITY_ATTRIBUTES SECURITY_ATTRIBUTES; typedef struct _SECURITY_ATTRIBUTES *LPSECURITY_ATTRIBUTES; typedef long LONG, *LPLONG; typedef int BOOL; typedef void *HANDLE; typedef const char *LPCSTR; typedef unsigned long DWORD; extern "C" { __declspec(dllimport) HANDLE __stdcall CreateSemaphoreA( LPSECURITY_ATTRIBUTES lpSemaphoreAttributes, LONG lInitialCount, LONG lMaximumCount, LPCSTR lpName ); __declspec(dllimport) BOOL __stdcall CloseHandle( HANDLE hObject ); __declspec(dllimport) BOOL __stdcall ReleaseSemaphore( HANDLE hSemaphore, LONG lReleaseCount, LPLONG lpPreviousCount ); __declspec(dllimport) DWORD __stdcall WaitForSingleObject( HANDLE hHandle, DWORD dwMilliseconds ); }; namespace BloombergLP { namespace bslmt { template <class SEMAPHORE_POLICY> class SemaphoreImpl; // ============================================= // class SemaphoreImpl<Platform::Win32Semaphore> // ============================================= template <> class SemaphoreImpl<Platform::Win32Semaphore> { // This class provides a full specialization of 'SemaphoreImpl' for win32. // The implementation provided here defines an efficient POSIX like // semaphore. // DATA void *d_handle; // TBD doc bsls::AtomicInt d_resources; // if positive, number of available // resources if negative: number of waiting // threads (need this because Windows does // not provide a mechanism to get the // semaphore count) // NOT IMPLEMENTED SemaphoreImpl(const SemaphoreImpl&); SemaphoreImpl& operator=(const SemaphoreImpl&); public: // CREATORS SemaphoreImpl(int count); // Create a semaphore initially having the specified 'count'. ~SemaphoreImpl(); // Destroy a semaphore // MANIPULATORS void post(); // Atomically increment the count of this semaphore. void post(int number); // Atomically increment the count of this semaphore by the specified // 'number'. The behavior is undefined unless 'number > 0'. int tryWait(); // Decrement the count of this semaphore if it is positive and return // 0. Return a non-zero value otherwise. void wait(); // Block until the count of this semaphore is a positive value and // atomically decrement it. // ACCESSORS int getValue() const; // Return the current value of this semaphore. }; } // close package namespace // ============================================================================ // INLINE DEFINITIONS // ============================================================================ // --------------------------------------------- // class SemaphoreImpl<Platform::Win32Semaphore> // --------------------------------------------- // CREATORS inline bslmt::SemaphoreImpl<bslmt::Platform::Win32Semaphore>::SemaphoreImpl(int count) : d_resources(count) { // Create a semaphore with a 0 count, since the count is actually // maintained in 'd_resources'. d_handle = CreateSemaphoreA(NULL, 0, INT_MAX, NULL); } inline bslmt::SemaphoreImpl<bslmt::Platform::Win32Semaphore>::~SemaphoreImpl() { CloseHandle(d_handle); } // MANIPULATORS inline void bslmt::SemaphoreImpl<bslmt::Platform::Win32Semaphore>::post() { if (++d_resources <= 0) { ReleaseSemaphore(d_handle, 1, NULL); } } inline void bslmt::SemaphoreImpl<bslmt::Platform::Win32Semaphore>::wait() { if (--d_resources >= 0) { return; } WaitForSingleObject(d_handle, 0xFFFFFFFF /*INFINITE*/); } // ACCESSORS inline int bslmt::SemaphoreImpl<bslmt::Platform::Win32Semaphore>::getValue() const { const int v = d_resources; return v > 0 ? v : 0; } } // close enterprise namespace #endif // BSLMT_PLATFORM_WIN32_THREADS #endif // ---------------------------------------------------------------------------- // Copyright 2015 Bloomberg Finance L.P. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // ----------------------------- END-OF-FILE ----------------------------------