// gold-threads.h -- thread support for gold -*- C++ -*-
-// Copyright 2006, 2007 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
namespace gold
{
-class Lock_impl;
class Condvar;
+class Initialize_lock_once;
+
+// The interface for the implementation of a Lock.
+
+class Lock_impl
+{
+ public:
+ Lock_impl()
+ { }
+
+ virtual
+ ~Lock_impl()
+ { }
+
+ virtual void
+ acquire() = 0;
+
+ virtual void
+ release() = 0;
+};
// A simple lock class.
{
public:
Lock();
+
~Lock();
// Acquire the lock.
void
- acquire();
+ acquire()
+ { this->lock_->acquire(); }
// Release the lock.
void
- release();
+ release()
+ { this->lock_->release(); }
private:
// This class can not be copied.
Lock& lock_;
};
-class Condvar_impl;
+class Hold_optional_lock
+{
+ public:
+ Hold_optional_lock(Lock* lock)
+ : lock_(lock)
+ {
+ if (this->lock_ != NULL)
+ this->lock_->acquire();
+ }
+
+ ~Hold_optional_lock()
+ {
+ if (this->lock_ != NULL)
+ this->lock_->release();
+ }
+
+ private:
+ Hold_optional_lock(const Hold_optional_lock&);
+ Hold_optional_lock& operator=(const Hold_optional_lock&);
+
+ Lock* lock_;
+};
+
+// The interface for the implementation of a condition variable.
+
+class Condvar_impl
+{
+ public:
+ Condvar_impl()
+ { }
+
+ virtual
+ ~Condvar_impl()
+ { }
+
+ virtual void
+ wait(Lock_impl*) = 0;
+
+ virtual void
+ signal() = 0;
+
+ virtual void
+ broadcast() = 0;
+};
// A simple condition variable class. It is always associated with a
// specific lock.
// Wait for the condition variable to be signalled. This should
// only be called when the lock is held.
void
- wait();
+ wait()
+ { this->condvar_->wait(this->lock_.get_impl()); }
+
+ // Signal the condition variable--wake up at least one thread
+ // waiting on the condition variable. This should only be called
+ // when the lock is held.
+ void
+ signal()
+ { this->condvar_->signal(); }
- // Signal the condition variable. This should only be called when
- // the lock is held.
+ // Broadcast the condition variable--wake up all threads waiting on
+ // the condition variable. This should only be called when the lock
+ // is held.
void
- signal();
+ broadcast()
+ { this->condvar_->broadcast(); }
private:
// This class can not be copied.
Condvar_impl* condvar_;
};
+// A class used to initialize a lock exactly once, after the options
+// have been read. This is needed because the implementation of locks
+// depends on whether we've seen the --threads option. Before the
+// options have been read, we know we are single-threaded, so we can
+// get by without using a lock. This class should be an instance
+// variable of the class which has a lock which needs to be
+// initialized.
+
+class Initialize_lock
+{
+ public:
+ // The class which uses this will have a pointer to a lock. This
+ // must be constructed with a pointer to that pointer.
+ Initialize_lock(Lock** pplock);
+
+ // Initialize the lock. Return true if the lock is now initialized,
+ // false if it is not (because the options have not yet been read).
+ bool
+ initialize();
+
+ private:
+ // A pointer to the lock pointer which must be initialized.
+ Lock** const pplock_;
+ // If needed, a pointer to a pthread_once_t structure.
+ Initialize_lock_once* once_;
+};
+
} // End namespace gold.
#endif // !defined(GOLD_THREADS_H)