56 lines
1.9 KiB
C++
56 lines
1.9 KiB
C++
/* sync.h: Header file for cygwin synchronization primitives.
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Copyright 1999, 2000 Cygnus Solutions.
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Written by Christopher Faylor <cgf@cygnus.com>
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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/* FIXME: Note that currently this class cannot be allocated via `new' since
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there are issues with malloc and fork. */
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class muto
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{
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LONG sync; /* Used to serialize access to this class. */
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LONG visits; /* Count of number of times a thread has called acquire. */
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LONG waiters; /* Number of threads waiting for lock. */
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HANDLE bruteforce; /* event handle used to control waiting for lock. */
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DWORD tid; /* Thread Id of lock owner. */
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public:
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class muto *next;
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const char *name;
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void *operator new (size_t, void *p) {return p;}
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void *operator new (size_t) {return ::new muto; }
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void operator delete (void *) {;} /* can't handle allocated mutos
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currently */
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/* This simple constructor is used for cases where no bruteforce
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event handling is required. */
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muto(): sync(0), visits(0), waiters(-1), bruteforce(0), tid(0), next (NULL) {;}
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/* A more complicated constructor. */
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muto(int inh, const char *name);
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~muto ();
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int acquire (DWORD ms = INFINITE); /* Acquire the lock. */
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int release (); /* Release the lock. */
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/* Return true if caller thread owns the lock. */
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int ismine () {return tid == GetCurrentThreadId ();}
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DWORD owner () {return tid;}
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int unstable () {return !tid && (sync || waiters >= 0);}
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};
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extern muto muto_start;
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/* Use a statically allocated buffer as the storage for a muto */
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#define new_muto(__inh, __name) \
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({ \
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static NO_COPY muto __mbuf; \
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(void) new ((char *) &__mbuf) muto (__inh, __name); \
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__mbuf.next = muto_start.next; \
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muto_start.next = &__mbuf; \
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&__mbuf; \
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})
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