106 lines
2.7 KiB
C++
106 lines
2.7 KiB
C++
/**
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* @file
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*/
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#pragma once
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#include <windows.h>
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#include <exception>
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#include <string>
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/**
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* Encapsulates a Win32 critical section.
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* Provides control over creation and clean destruction of native win32 critical sections. Also
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* allows the object to be used directly in place of a CRITICAL_SECTION handle via the void* overload
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*
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* @author Peter Hancock
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*
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*/
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class CriticalSection
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{
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public:
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/**
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* Create the critical section.
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*/
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CriticalSection()
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{
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::InitializeCriticalSection(&cs);
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}
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/**
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* Cleans up the critical section.
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*/
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~CriticalSection(void)
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{
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::DeleteCriticalSection(&cs);
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}
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/**
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* Enters a critical section of code.
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* Prevents other threads from accessing the section between the enter and leave sections simultaneously.
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* @note It is good practice to try and keep the critical section code as little as possible, so that
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* other threads are not locked waiting for it.
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*/
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void enter(void)
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{
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::EnterCriticalSection(&cs);
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}
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/**
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* Leaves the critical section.
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* Allows threads access to the critical code section again.
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* @warning Note that an exception occurring with a critical section may not result in the expected leave being
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* called. To ensure that your critical section is exception safe, ensure that you wrap the critical
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* section in a try catch, and the catch calls the leave method.
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*/
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void leave(void)
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{
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::LeaveCriticalSection(&cs);
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}
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/**
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* Provides conversion to the native WIN32 CRITICAL_SECTION object
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* Allows the client to use the CriticalSection object as a native handle also.
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* @return CRITICAL_SECTION handle
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*/
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operator CRITICAL_SECTION&()
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{
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return cs;
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}
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private:
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CriticalSection(const CriticalSection&); // Disable copy constructor
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CriticalSection& operator=(const CriticalSection&); // Disable assignment
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CRITICAL_SECTION cs;
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};
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/**
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* CGuard class provides exception safety for critical sections
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* A helper class that enters a critical section on construction, and leaves
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* the critical section on destruction.
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*
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* @code
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int i;
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{
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CGuard loopGuard(moduleCS); // enters the critical section
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for(int i=0 ; i < 10 ; i++)
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{
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// Do stuff here // If an exception is thrown here, loopGuard goes out of scope - calling leave()
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}
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} // Guard goes out of scope here, destructor calls leave()
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* @endcode
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*
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* @author Peter Hancock
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*
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*/
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class CGuard
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{
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public:
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CGuard(CriticalSection& sectionName) : cs(sectionName)
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{
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cs.enter();
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}
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~CGuard()
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{
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cs.leave();
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}
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private:
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CriticalSection& cs;
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CGuard(const CGuard& copy);
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operator=(const CGuard& rhs);
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};
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