Initial CVS checkin of gold

1 files changed, 101 insertions, 0 deletions

diff --git a/gold/gold-threads.h b/gold/gold-threads.h
new file mode 100644
index 00000000000..e2a8388ac13
--- /dev/null
+++ b/gold/gold-threads.h
@@ -0,0 +1,101 @@
+// gold-threads.h -- thread support for gold  -*- C++ -*-
+
+// gold can be configured to support threads.  If threads are
+// supported, the user can specify at runtime whether or not to
+// support them.  This provides an interface to manage locking
+// accordingly.
+
+// Lock
+//   A simple lock class.
+
+#ifndef GOLD_THREADS_H
+#define GOLD_THREADS_H
+
+namespace gold
+{
+
+class Lock_impl;
+class Condvar;
+
+// A simple lock class.
+
+class Lock
+{
+ public:
+  Lock();
+  ~Lock();
+
+  // Acquire the lock.
+  void
+  acquire();
+
+  // Release the lock.
+  void
+  release();
+
+ private:
+  // This class can not be copied.
+  Lock(const Lock&);
+  Lock& operator=(const Lock&);
+
+  friend class Condvar;
+  Lock_impl*
+  get_impl() const
+  { return this->lock_; }
+
+  Lock_impl* lock_;
+};
+
+// RAII for Lock.
+
+class Hold_lock
+{
+ public:
+  Hold_lock(Lock& lock)
+    : lock_(lock)
+  { this->lock_.acquire(); }
+
+  ~Hold_lock()
+  { this->lock_.release(); }
+
+ private:
+  // This class can not be copied.
+  Hold_lock(const Hold_lock&);
+  Hold_lock& operator=(const Hold_lock&);
+
+  Lock& lock_;
+};
+
+class Condvar_impl;
+
+// A simple condition variable class.  It is always associated with a
+// specific lock.
+
+class Condvar
+{
+ public:
+  Condvar(Lock& lock);
+  ~Condvar();
+
+  // Wait for the condition variable to be signalled.  This should
+  // only be called when the lock is held.
+  void
+  wait();
+
+  // Signal the condition variable.  This should only be called when
+  // the lock is held.
+  void
+  signal();
+
+ private:
+  // This class can not be copied.
+  Condvar(const Condvar&);
+  Condvar& operator=(const Condvar&);
+
+  Lock& lock_;
+  Condvar_impl* condvar_;
+};
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_THREADS_H)