1 files changed, 122 insertions, 0 deletions
diff --git a/src/base/callback.hh b/src/base/callback.hh
new file mode 100644
index 000000000..7b3023505
--- /dev/null
+++ b/src/base/callback.hh
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2003-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __CALLBACK_HH__
+#define __CALLBACK_HH__
+
+#include <list>
+
+/**
+ * Generic callback class.  This base class provides a virtual process
+ * function that gets called when the callback queue is processed.
+ */
+class Callback
+{
+  public:
+    /**
+     * virtualize the destructor to make sure that the correct one
+     * gets called.
+     */
+    virtual ~Callback() {}
+
+    /**
+     * virtual process function that is invoked when the callback
+     * queue is executed.
+     */
+    virtual void process() = 0;
+};
+
+class CallbackQueue
+{
+  protected:
+    /**
+     * Simple typedef for the data structure that stores all of the
+     * callbacks.
+     */
+    typedef std::list<Callback *> queue;
+
+    /**
+     * List of all callbacks.  To be called in fifo order.
+     */
+    queue callbacks;
+
+  public:
+    /**
+     * Add a callback to the end of the queue
+     * @param callback the callback to be added to the queue
+     */
+    void add(Callback *callback)
+    {
+        callbacks.push_back(callback);
+    }
+
+    /**
+     * Find out if there are any callbacks in the queue
+     */
+    bool empty() const { return callbacks.empty(); }
+
+    /**
+     * process all callbacks
+     */
+    void process()
+    {
+        queue::iterator i = callbacks.begin();
+        queue::iterator end = callbacks.end();
+
+        while (i != end) {
+            (*i)->process();
+            ++i;
+        }
+    }
+
+    /**
+     * clear the callback queue
+     */
+    void clear()
+    {
+        callbacks.clear();
+    }
+};
+
+/// Helper template class to turn a simple class member function into
+/// a callback.
+template <class T, void (T::* F)()>
+class MakeCallback : public Callback
+{
+  private:
+    T *object;
+
+  public:
+    MakeCallback(T *o)
+        : object(o)
+    { }
+
+    void process() { (object->*F)(); }
+};
+
+#endif // __CALLBACK_HH__