From 250e3ba4dff24034990f26e13fcd46a2bb64ca11 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Sat, 27 Dec 2008 06:58:13 +0100
Subject: [PATCH] add a convenience shortcut for waiting on a bool member
 function

---
 src/lib/sync.hpp                | 43 +++++++++++++++++++++++++++------
 tests/lib/sync-waiting-test.cpp | 27 +++++++++++++++++++--
 2 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/src/lib/sync.hpp b/src/lib/sync.hpp
index 08fdbdfdb..8fa456e1a 100644
--- a/src/lib/sync.hpp
+++ b/src/lib/sync.hpp
@@ -47,14 +47,12 @@ extern "C" {
 #include "lib/condition.h"
 }
 
-#include <boost/scoped_ptr.hpp>
 #include <cerrno>
 #include <ctime>
 
 
 namespace lib {
-
-    using boost::scoped_ptr;
+    
     
     
     /** Helpers and building blocks for Monitor based synchronisation */
@@ -229,6 +227,19 @@ namespace lib {
          
           bool operator() () { return flag_; }
         };
+
+
+      template<class X>
+      struct BoolMethodPredicate
+        {
+          typedef volatile bool (X::*Method)(void);
+          
+          X& instance_;
+          Method method_;
+          BoolMethodPredicate (X& x, Method m) : instance_(x), method_(m) {}
+         
+          bool operator() () { return (instance_.*method_)(); }
+        };
       
       
       template<class IMPL>
@@ -246,12 +257,21 @@ namespace lib {
           
           void signal(bool a){ IMPL::signal(a); }
           
-          bool wait (Flag flag, ulong timedwait=0)
+          bool
+          wait (Flag flag, ulong timedwait=0)
             {
               BoolFlagPredicate checkFlag(flag);
               return IMPL::wait(checkFlag, timeout_.setOffset(timedwait));                                   
             }
           
+          template<class X>
+          bool
+          wait (X& instance, volatile bool (X::*method)(void), ulong timedwait=0)
+            {
+              BoolMethodPredicate<X> invokeMethod(instance, method);
+              return IMPL::wait(invokeMethod, timeout_.setOffset(timedwait));                                   
+            }
+          
           void setTimeout(ulong relative) {timeout_.setOffset(relative);}
           bool isTimedWait()              {return (timeout_);}
         };
@@ -308,13 +328,20 @@ namespace lib {
             Lock(Monitor& m) : mon_(m)        { mon_.acquireLock(); }
             ~Lock()                           { mon_.releaseLock(); }
             
-            template<typename C>
-            bool wait (C& cond, ulong time=0) { return mon_.wait(cond,time);}
+            void notify()                     { mon_.signal(false);}
+            void notifyAll()                  { mon_.signal(true); }
             void setTimeout(ulong time)       { mon_.setTimeout(time); }
             
-            void notifyAll()                  { mon_.signal(true); }
-            void notify()                     { mon_.signal(false);}
+            template<typename C>
+            bool wait (C& cond, ulong time=0) { return mon_.wait(cond,time);}
             
+            template<class X>
+            Lock(X* it, volatile bool (X::*method)(void))
+              : mon_(getMonitor(it)) 
+              { 
+                mon_.acquireLock();
+                mon_.wait(*it,method);
+              }
           };
         
         
diff --git a/tests/lib/sync-waiting-test.cpp b/tests/lib/sync-waiting-test.cpp
index c25505554..2807d92f4 100644
--- a/tests/lib/sync-waiting-test.cpp
+++ b/tests/lib/sync-waiting-test.cpp
@@ -64,11 +64,13 @@ namespace lib {
         };
       
       
+      /** demonstrates how to wait on a simple boolean flag */
       class SyncOnBool
         : public Token,
           public Sync<NonrecursiveLock_Waitable>
         {
-          bool got_new_data_;
+        protected:
+          volatile bool got_new_data_;
           
         public:
           SyncOnBool() : got_new_data_ (false) {}
@@ -88,6 +90,24 @@ namespace lib {
             }
         };
       
+      
+      /** this variant demonstrates how to wait on an condition
+       *  defined in terms of a (bool) member function
+       */
+      class SyncOnMemberPredicate
+        : public SyncOnBool
+        {
+          volatile bool checkTheFlag() { return this->got_new_data_; }
+          
+        public:
+          void getIt()
+            {
+              Lock guard(this, &SyncOnMemberPredicate::checkTheFlag);
+              sum_ += input_;
+            }
+          
+        };
+      
     } // (End) test classes and data....
     
     
@@ -115,9 +135,12 @@ namespace lib {
           {
             if (!Glib::thread_supported()) 
               Glib::thread_init();
-
+            
             SyncOnBool use_sync_var;
             waitPingPong (use_sync_var);
+            
+            SyncOnMemberPredicate use_member_pred;
+            waitPingPong (use_member_pred);
           }