// bslmt_muteximpl_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_MUTEXIMPL_WIN32
#define INCLUDED_BSLMT_MUTEXIMPL_WIN32
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide a win32 implementation of 'bslmt::Mutex'.
//
//@CLASSES:
// bslmt::MutexImpl<Platform::Win32Threads>: win32 specialization
//
//@SEE_ALSO: bslmt_mutex
//
//@DESCRIPTION: This component provides an implementation of 'bslmt::Mutex' for
// Windows (win32), 'bslmt::MutexImpl<Platform::Win32Threads>', via the
// template specialization:
//..
// bslmt::MutexImpl<Platform::Win32Threads>
//..
// This template class should not be used (directly) by client code. Clients
// should instead use 'bslmt::Mutex'.
//
///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>
#include <bsls_platform.h>
#ifdef BSLMT_PLATFORM_WIN32_THREADS
// Platform-specific implementation starts here.
// Rather than setting 'WINVER' or 'NTDDI_VERSION', just forward declare the
// Windows 2000 functions that are used.
struct _RTL_CRITICAL_SECTION;
typedef struct _RTL_CRITICAL_SECTION CRITICAL_SECTION, *LPCRITICAL_SECTION;
typedef int BOOL;
typedef unsigned long DWORD;
extern "C" {
__declspec(dllimport) BOOL __stdcall InitializeCriticalSectionAndSpinCount(
LPCRITICAL_SECTION lpCriticalSection,
DWORD dwSpinCount);
__declspec(dllimport) void __stdcall DeleteCriticalSection(
LPCRITICAL_SECTION lpCriticalSection);
__declspec(dllimport) BOOL __stdcall TryEnterCriticalSection(
LPCRITICAL_SECTION lpCriticalSection);
__declspec(dllimport) void __stdcall EnterCriticalSection(
LPCRITICAL_SECTION lpCriticalSection);
__declspec(dllimport) void __stdcall LeaveCriticalSection(
LPCRITICAL_SECTION lpCriticalSection);
} // extern "C"
namespace BloombergLP {
namespace bslmt {
template <class THREAD_POLICY>
class MutexImpl;
// =======================================
// class MutexImpl<Platform::Win32Threads>
// =======================================
template <>
class MutexImpl<Platform::Win32Threads> {
// This class provides a full specialization of 'MutexImpl' for Windows.
// It provides an efficient proxy for Windows critical sections, and
// related operations. Note that the mutex implemented in this class is
// *not* error checking, and is non-recursive.
// TYPES
public:
enum {
// Size of the buffer allocated for the critical section, in
// pointer-sized elements. We have to make it public so we could
// access it in a .cpp file to verify the size.
#ifdef BSLS_PLATFORM_CPU_64_BIT
// 5*8 = 40 bytes
k_CRITICAL_SECTION_BUFFER_SIZE = 5
#else
// 6*4 = 24 bytes
k_CRITICAL_SECTION_BUFFER_SIZE = 6
#endif
};
private:
enum {
// A Windows critical section has a configurable spin count. A lock
// operation spins this many iterations (on, presumably, some atomic
// integer) before sleeping on the underlying primitive.
k_SPIN_COUNT = 30
};
// DATA
void *d_lock[k_CRITICAL_SECTION_BUFFER_SIZE];
// NOT IMPLEMENTED
MutexImpl(const MutexImpl&);
MutexImpl& operator=(const MutexImpl&);
public:
// PUBLIC TYPES
typedef _RTL_CRITICAL_SECTION NativeType;
// The underlying OS-level type. Exposed so that other bslmt components
// can operate directly on this mutex.
// CREATORS
MutexImpl();
// Create a mutex initialized to an unlocked state.
~MutexImpl();
// Destroy this mutex object.
// MANIPULATORS
void lock();
// Acquire a lock on this mutex object. If this object is currently
// locked, then suspend execution of the current thread until a lock
// can be acquired. Note that the behavior is undefined if the calling
// thread already owns the lock on this mutex, and will likely result
// in a deadlock.
NativeType& nativeMutex();
// Return a reference to the modifiable OS-level mutex underlying this
// object. This method is intended only to support other bslmt
// components that must operate directly on this mutex.
int tryLock();
// Attempt to acquire a lock on this mutex object. Return 0 on
// success, and a non-zero value of this object is already locked, or
// if an error occurs.
void unlock();
// Release a lock on this mutex that was previously acquired through a
// successful call to 'lock', or 'tryLock'. The behavior is undefined,
// unless the calling thread currently owns the lock on this mutex.
};
} // close package namespace
// ============================================================================
// INLINE DEFINITIONS
// ============================================================================
// ---------------------------------------
// class MutexImpl<Platform::Win32Threads>
// ---------------------------------------
// CREATORS
inline
bslmt::MutexImpl<bslmt::Platform::Win32Threads>::MutexImpl()
{
InitializeCriticalSectionAndSpinCount(
reinterpret_cast<_RTL_CRITICAL_SECTION *>(d_lock), k_SPIN_COUNT);
}
inline
bslmt::MutexImpl<bslmt::Platform::Win32Threads>::~MutexImpl()
{
DeleteCriticalSection(
reinterpret_cast<_RTL_CRITICAL_SECTION*>(d_lock));
}
// MANIPULATORS
inline
void bslmt::MutexImpl<bslmt::Platform::Win32Threads>::lock()
{
EnterCriticalSection(
reinterpret_cast<_RTL_CRITICAL_SECTION*>(d_lock));
}
inline
bslmt::MutexImpl<bslmt::Platform::Win32Threads>::NativeType&
bslmt::MutexImpl<bslmt::Platform::Win32Threads>::nativeMutex()
{
return *reinterpret_cast<_RTL_CRITICAL_SECTION*>(d_lock);
}
inline
int bslmt::MutexImpl<bslmt::Platform::Win32Threads>::tryLock()
{
return !TryEnterCriticalSection(
reinterpret_cast<_RTL_CRITICAL_SECTION*>(d_lock));
}
inline
void bslmt::MutexImpl<bslmt::Platform::Win32Threads>::unlock()
{
LeaveCriticalSection(
reinterpret_cast<_RTL_CRITICAL_SECTION*>(d_lock));
}
} // 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 ----------------------------------