- Incapsulate code so that the hack we previously used in CPUPoliciesGatekeeper isn't needed anymore

- Now CPUPolicy has a callback method for scripting languages, but it is up to derived classes to take
mutexes and set the value when needed (maybe we can improve this?)


git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@862 3ecf2c5c-341e-0410-92b4-d18e462d057c

plugins/pyloader/src/CPUPolicy.py

@@ -97,7 +97,7 @@ class CPUPolicy:
     #
     # @return A sgpem::PolicyParameters instance
     def get_parameters(self):
-        return sgpem.CPUPolicy.get_active_policy().get_parameters()
+        return sgpem.CPUPolicy.callback_get_policy().get_parameters()
 
     
     ## @brief This function implements an in-place stable sort

plugins/pyloader/src/python_cpu_policy.cc

@@ -29,6 +29,11 @@ using namespace std;
 
 #define WAIT_FOR (250000)
 
+
+// Static member data
+Glib::StaticRecMutex PythonCPUPolicy::_mtx = GLIBMM_STATIC_REC_MUTEX_INIT;
+
+
 // WARNING :  this class needs extensive and above all
 // *strong* exception checking / handling!
 
@@ -89,19 +94,29 @@ PythonCPUPolicy::~PythonCPUPolicy()
 void
 PythonCPUPolicy::activate() throw(UserInterruptException, MalformedPolicyException)
 {
+  Glib::RecMutex::Lock lock(_mtx);;
+  set_callback_policy(const_cast<PythonCPUPolicy*>(this));
+
   // FIXME write the rest, taking away code from constructor
 
   configure();
+  
+  set_callback_policy(NULL);
 }
 
 
 void
 PythonCPUPolicy::deactivate()
 {
+  Glib::RecMutex::Lock lock(_mtx);;
+  set_callback_policy(const_cast<PythonCPUPolicy*>(this));
+
   // FIXME See if some code has to be moved here from the
   // destructor, AFTER having written activate()
 
   _parameters.clear();
+
+  set_callback_policy(NULL);
 }
 
 
@@ -109,16 +124,24 @@ PythonCPUPolicy::deactivate()
 void
 PythonCPUPolicy::configure() throw(UserInterruptException, MalformedPolicyException)
 {
+  Glib::RecMutex::Lock lock(_mtx);;
+  set_callback_policy(const_cast<PythonCPUPolicy*>(this));
+
   PyObject* retval = PyObject_CallMethod(_adapter, "async_configure", NULL);
   Py_DECREF(retval);
 
   wait_unlock();
+
+  set_callback_policy(NULL);
 }
 
 
 void
 PythonCPUPolicy::sort_queue() const throw(UserInterruptException, MalformedPolicyException)
 {  
+  Glib::RecMutex::Lock lock(_mtx);;
+  set_callback_policy(const_cast<PythonCPUPolicy*>(this));
+
   PyObject* retval = PyObject_CallMethod(_adapter, "async_sort_queue", NULL);
 
   // Do minimal debugging
@@ -126,6 +149,8 @@ PythonCPUPolicy::sort_queue() const throw(UserInterruptException, MalformedPolic
   else Py_DECREF(retval);
 
   wait_unlock();
+
+  set_callback_policy(NULL);
 }
 
 
@@ -145,6 +170,9 @@ PythonCPUPolicy::get_name() const
 bool
 PythonCPUPolicy::is_pre_emptive() const throw(UserInterruptException, MalformedPolicyException)
 {
+  Glib::RecMutex::Lock lock(_mtx);;
+  set_callback_policy(const_cast<PythonCPUPolicy*>(this));
+
   PyObject* retval = PyObject_CallMethod(_adapter, "async_is_preemptive", NULL);
   Py_DECREF(retval);
 
@@ -155,6 +183,8 @@ PythonCPUPolicy::is_pre_emptive() const throw(UserInterruptException, MalformedP
   assert(retval);
   bool ret = PyObject_IsTrue(retval);
   Py_DECREF(retval);
+
+  set_callback_policy(NULL);
   return ret;
 }
 
@@ -162,6 +192,9 @@ PythonCPUPolicy::is_pre_emptive() const throw(UserInterruptException, MalformedP
 int
 PythonCPUPolicy::get_time_slice() const throw(UserInterruptException, MalformedPolicyException)
 {
+  Glib::RecMutex::Lock lock(_mtx);;
+  set_callback_policy(const_cast<PythonCPUPolicy*>(this));
+
   PyObject* retval = PyObject_CallMethod(_adapter, "async_get_time_slice", NULL);
 
   // Do minimal debugging
@@ -176,6 +209,7 @@ PythonCPUPolicy::get_time_slice() const throw(UserInterruptException, MalformedP
   long tmp = PyInt_AsLong(retval);
   Py_DECREF(retval);
 
+  set_callback_policy(NULL);
   return tmp < 0 ? numeric_limits<int>::max() : static_cast<int>(tmp);
 }
 
@@ -208,7 +242,7 @@ PythonCPUPolicy::wait_unlock() const throw(UserInterruptException, MalformedPoli
       PyEval_RestoreThread(_save);
 
       if(PyErr_Occurred() != NULL)
-	abort();
+        abort();
     
       throw UserInterruptException(_("User-defined policy is "
                                      "taking too long to terminate."));

plugins/pyloader/src/python_cpu_policy.hh

@@ -24,6 +24,7 @@
 #include "config.h"
 
 #include <Python.h>
+#include <glibmm/thread.h>
 #include <glibmm/ustring.h>
 
 #include <iostream>
@@ -63,7 +64,7 @@ namespace sgpem
     */
     Glib::ustring          get_description() const;
 
-    Glib::ustring  get_name() const;
+    Glib::ustring          get_name() const;
 
     /**
      \returns \c TRUE if the policy is preemptive.
@@ -87,6 +88,8 @@ namespace sgpem
     void wait_unlock() const throw(UserInterruptException, MalformedPolicyException);
     static std::string get_exception_information();
 
+    static Glib::StaticRecMutex _mtx;
+    
     PyObject* _upolicy_dict;
     PyObject* _adapter;
 

plugins/pyloader/src/sgpem.i

@@ -67,26 +67,10 @@ namespace sgpem {
 		virtual ~CPUPolicy() = 0;
 		sgpem::PolicyParameters& get_parameters();
 
-    %extend {
-      // Convenience function to get the current policy
-      static CPUPolicy* get_active_policy()
-      {
-        History& h = Simulation::get_instance().get_history();
-        return CPUPoliciesGatekeeper::get_instance().get_current_policy(&h);
-      };
-    }
+    static CPUPolicy* callback_get_policy() throw(std::runtime_error);
 	};
   
-    // --------------------------------------------
-
-// 	class PolicyParametersException : public std::runtime_error {
-// 	public:
-// 		PolicyParametersException(char* msg);
-// 		%rename (__str__) what;
-// 		virtual const char* what();
-// 	}; //~ class PolicyParametersException
-  
-    // --------------------------------------------
+  // --------------------------------------------
 	class PolicyParameters 
 	{
 	public:

src/backend/cpu_policies_gatekeeper.cc

@@ -118,25 +118,11 @@ CPUPoliciesGatekeeper::activate_policy(History *history, CPUPolicy* policy) thro
   
   try
   {
-    // policy->activate() needs already an active policy, because:
-    //   * it calls the configure() method on the 
-    //     insert-your-favourite-scripting-language-here-policy
-    //   * which in turn calls the configure() method in the 
-    //     code written by the user
-    //   * which probably uses Simulation to get the _active_ C++ policy,
-    //     so it can get its policy_parameters()
-    //  ... so **DON'T** play Mr. Clever Dick and swap the following two
-    //    lines in an optimization frenzy! Or the user policy WILL fail.
-    _active_policies[history] = policy;
     policy->activate();
+    _active_policies[history] = policy;
   }
   catch(const CPUPolicyException& e)
   {    
-    //std::cerr << e.what() << std::endl;
-    // See the comment above to understand why we do this
-    // in this way
-    _active_policies.erase(_active_policies.find(history));
-    
     // the caller need to know if it failed
     throw;
   }

src/backend/cpu_policy.cc

@@ -22,6 +22,11 @@
 using namespace std;
 using namespace sgpem;
 
+
+// Static member data
+CPUPolicy*  CPUPolicy::_callback_policy = NULL;
+
+
 CPUPolicy::~CPUPolicy()
 {}
 
@@ -31,3 +36,20 @@ CPUPolicy::get_parameters()
 {
   return _parameters;
 }
+
+
+
+CPUPolicy* 
+CPUPolicy::callback_get_policy() throw(std::runtime_error)
+{
+  if(_callback_policy == NULL)
+    throw std::runtime_error("CPUPolicy::callback_get_policy() not used as a callback method. NULL ptr returned.");
+  return _callback_policy;
+}
+
+
+void
+CPUPolicy::set_callback_policy(CPUPolicy* ptr)
+{
+  _callback_policy = ptr;
+}

src/backend/cpu_policy.hh

@@ -30,6 +30,8 @@
 #include "user_interrupt_exception.hh"
 #include "malformed_policy_exception.hh"
 
+#include <stdexcept>
+
 namespace sgpem
 {
   class CPUPolicy;
@@ -102,8 +104,18 @@ namespace sgpem
      */
     PolicyParameters& get_parameters();
 
+    /** This method is used only as a callback by scripting languages */
+    static CPUPolicy* callback_get_policy() throw(std::runtime_error);
+    
   protected:
-    PolicyParameters _parameters;
+    PolicyParameters            _parameters;
+
+    static void       set_callback_policy(CPUPolicy* ptr = NULL);
+
+  private:
+    // Used by callback_get_policy:
+    static CPUPolicy*     _callback_policy;
+
   };
 
 }//~ namespace sgpem