import winsup-2000-02-17 snapshot

winsup/cygwin/sync.h

@@ -0,0 +1,48 @@
+/* sync.h: Header file for cygwin synchronization primitives.
+
+   Copyright 1999 Cygnus Solutions.
+
+   Written by Christopher Faylor <cgf@cygnus.com>
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+/* FIXME: Note that currently this class cannot be allocated via `new' since
+   there are issues with malloc and fork. */
+class muto
+{
+  LONG sync;	/* Used to serialize access to this class. */
+  LONG visits;	/* Count of number of times a thread has called acquire. */
+  LONG waiters;	/* Number of threads waiting for lock. */
+  HANDLE bruteforce; /* event handle used to control waiting for lock. */
+  DWORD tid;	/* Thread Id of lock owner. */
+public:
+  void *operator new (size_t, void *p) {return p;}
+  void *operator new (size_t n) {return ::new muto; }
+  void operator delete (void *p) {;} /* can't handle allocated mutos
+					currently */
+
+  /* This simple constructor is used for cases where no bruteforce
+     event handling is required. */
+  muto(): sync(0), visits(0), waiters(-1), bruteforce(0), tid(0) {;}
+  /* A more complicated constructor. */
+  muto(int inh, const char *name);
+  ~muto ();
+  int acquire (DWORD ms = INFINITE); /* Acquire the lock. */
+  int release ();		     /* Release the lock. */
+
+  /* Return true if caller thread owns the lock. */
+  int ismine () {return tid == GetCurrentThreadId ();}
+};
+
+/* Use a statically allocated buffer as the storage for a muto */
+#define new_muto(__inh, __name) \
+({ \
+  static NO_COPY char __mbuf[sizeof(class muto) + 100] = {0}; \
+  muto *m; \
+  m = new (__mbuf) muto ((__inh), (__name)); \
+  m; \
+})