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96 lines
2.4 KiB
C++
96 lines
2.4 KiB
C++
#ifndef _CRITSEC_H
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#define _CRITSEC_H
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#ifdef _WIN32
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#include <windows.h>
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#elif defined(__APPLE__)
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#include <CoreServices/CoreServices.h>
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#endif
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#include <bfc/common.h>
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#include <bfc/bfc_assert.h>
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/**
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CriticalSection is a portable object that implements a critical section,
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which is to say, it ensures that no two threads can be in that same
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section of code at the same time. Usually you make them a global object
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or allocate them with new and pass them to both threads.
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@short Critical section class.
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@author Nullsoft
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@ver 1.0
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@see Thread
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@see InCriticalSection
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*/
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class CriticalSection {
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public:
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CriticalSection();
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virtual ~CriticalSection();
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/**
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Enters the critical section. If another thread is already in the critical
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section, the calling thread will be blocked until the other thread calls
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leave().
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@see leave()
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*/
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void enter();
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/**
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Leaves the critical section. If another thread is currently blocked on
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this critical section, it will be unblocked. If multiple threads are blocking
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only one will be unblocked.
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@see enter()
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*/
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void leave();
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/**
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Calls enter() and leave() in quick succession. Useful to make sure that no
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other thread is in the critical section (although another thread could
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immediately re-enter)
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@see enter()
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@see leave()
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*/
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void inout();
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private:
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#ifdef ASSERTS_ENABLED
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int within;
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#endif
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#ifdef _WIN32
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CRITICAL_SECTION cs;
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#elif defined(__APPLE__)
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MPCriticalRegionID cr;
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#endif
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};
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/**
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This is a little helper class to ease the use of class CriticalSection.
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When it is instantiated, it enters a given critical section. When it is
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destroyed, it leaves the given critical section.
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CriticalSection a_cs;
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void blah() {
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InCriticalSection cs(a_cs); // critical section protection begins
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if (test) {
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return 0; // critical section protection ends
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}
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// critical section protection still active!
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doSomething();
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return 1; // critical section protection ends
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}
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@author Nullsoft
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@see CriticalSection
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*/
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class InCriticalSection {
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public:
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InCriticalSection(CriticalSection *cs) : m_cs(cs) { m_cs->enter(); }
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InCriticalSection(CriticalSection &cs) : m_cs(&cs) { m_cs->enter(); }
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~InCriticalSection() { m_cs->leave(); }
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private:
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CriticalSection *m_cs;
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};
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#define _INCRITICALSECTION(id, x) InCriticalSection __I_C_S__##id(x)
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#define INCRITICALSECTION(x) _INCRITICALSECTION(__LINE__, x)
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#endif
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