- Add documentation for classes:

- (C++) PythonPolicyManager
  - (Python) Policy, ScriptAdapter, fcfs


git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@408 3ecf2c5c-341e-0410-92b4-d18e462d057c

src/backend/pyloader/Policy.py

@@ -3,28 +3,123 @@ from Abstract import *
 ## @brief This is the abstract class a user-defined policy
 # should inherit from
 #
-# This class also exposes the method sort, which can be
+# This class also exposes the method sort(), which can be
 # used to easily sort the queue of ready process with a
-# given compare function
+# user-defined given compare function.
 class Policy:
-    ## @var Avoid instantiation of an abstract class
+    ## @var Avoid instantiation of an abstract class.
+    # @see Abstract.Metaclass
     __metaclass__ = Metaclass
 
-    configure = AbstractMethod('configure')
-    sort_queue = AbstractMethod('sort_queue')
-    is_preemptive = AbstractMethod('is_preemptive')
-    get_time_slice = AbstractMethod('get_time_slice')
-    
-    ## @brief this function implements a quicksort in place
-    # using the SchedulableQueue methods
+    ## @brief Configure policy to initial values
     #
-    # The compare parameter should be a user defined function
-    # name returning either True or False, defined like:
+    # This is called just before a simulation starts, and is responsible
+    # to define the parameters the policy wants to expose to the user.
+    # For example, it may make the return value of is_preemptive configurable,
+    # or register an integer value for a the time slice duration.
+    #
+    # @warning How do the user access get_parameters()?
+    #
+    # Should be implemented with signature:
     # @code
-    # def compare(SchedulableA,SchedulableB):
-    #     return SchedulableA.someProperty() < SchedulableB.someProperty()
+    # def configure(self):
+    #      # function body
     # @endcode
     #
+    # @see sgpem::Policy::get_parameters()
+    configure = AbstractMethod('configure')
+
+    ## @brief Sort ready processes queue
+    #
+    # This method is called by the scheduler at each
+    # step of the simulation to sort the ready
+    # processes queue.
+    #
+    # Should be implemented with signature:
+    # @code
+    # def sort_queue(self, event, queue):
+    #      # function body
+    # @endcode
+    #
+    # @param event Enumeration value of type Scheduler::Event,
+    # needed by some policies to know the reason of
+    # the call
+    # @param queue The sgpem::SchedulableQueue to be sorted.
+    # Only some methods of it are implemented,
+    # notably get_item_at(position),
+    # swap(positionA, positionB) and size().
+    #
+    # @see Policy.sort()
+    sort_queue = AbstractMethod('sort_queue')
+
+    ## @brief Returns whether the policy wants to be preemptive,
+    # other than by normal time slice termination
+    #
+    # See the return value for a complete explanation. Please
+    # note how the word ``priority'' here has a general meaning:
+    # it indicates every process than can bubble up the sorted
+    # ready queue and come before another. So it's up to
+    # Policy.sort_queue() to give it a precise meaning.
+    # 
+    # Should be implemented with signature:
+    # @code
+    # def is_preemptive(self):
+    #      # function body
+    # @endcode
+    #
+    # @return True If the policy declares it wants the running
+    # process to be released if a process at higher priority
+    # is put at the beginning of the ready processes queue
+    # @return False If the policy always waits the end of the time
+    # slice (or a process blocking/termination, of course) before
+    # selecting a new running process, even if it has greater priority
+    # than the current one
+    is_preemptive = AbstractMethod('is_preemptive')
+
+    ## @brief Returns how long is a time-slice for this policy
+    #
+    # A time sliced policy should return a positive integer value,
+    # a policy which doesn't use slices should instead return -1.
+    # You're encouraged to use a user-configurable parameter via
+    # Policy.configure() if the policy is time-sliced, to ensure
+    # greater flexibility.
+    # 
+    # Should be implemented with signature:
+    # @code
+    # def get_time_slice(self):
+    #      # function body
+    # @endcode
+    #
+    # FIXME: what happens for ``return 0''? The same as ``return 1''?
+    #
+    # @return -1 If the policy doesn't want to use time slices
+    # @return 0+ To specify a time slice duration for this policy
+    get_time_slice = AbstractMethod('get_time_slice')
+    
+    ## @brief This function implements an in-place stable sort
+    # using directly SchedulableQueue methods
+    #
+    # The compare parameter should be a user defined binary
+    # function returning either True or False, defined in one
+    # of the following ways:
+    # @code
+    # # As a lambda anonymous function (preferred)
+    # cmpf = lambda x,y: x.someProperty() < y.someProperty()
+    #
+    # # As a normal *global* function
+    # def compare(a,b):
+    #     return a.someProperty < b.someProperty()
+    # cmpf = compare
+    # @endcode
+    #
+    # The call is then simply:
+    # @code
+    # def sort_queue() :
+    #     # ...
+    #     self.sort(queue, cmpf)
+    # @endcode
+    #
+    # @param self The object caller
     # @param queue The SchedulableQueue to be sorted in place
     # @param cmpf The binary function to use to compare elements
     # @returns None

src/backend/pyloader/ScriptAdapter.py

@@ -1,9 +1,10 @@
 import mutex, thread
 import sgpem
 
+## Var Global syncronization object
 _g_mutex = mutex.mutex()
 
-## @val Synchronized return value you can read from C++
+## @var Synchronized return value you can read from C++
 # when a threaded function returns
 _ret_val = None
 
@@ -15,18 +16,32 @@ _ret_val = None
 # the policy member functions on a different thread, so
 # to ensure asyncronous control.
 #
-# Instantiated in the C++ code, it should be instantiated like:
+# Instantiated in the C++ code, it is created like:
 # @code
 # adapter = ScriptAdapter(UserPolicyClass)
 # @endcode
+#
+# The user shouldn't care about this class at all.
 class ScriptAdapter :
+    ## @var The policy this ScriptAdapter will use for calls
     _policy = None
+
+    ## @var The event to pass to Policy.sort_queue() after the asynchronous call
     _event = None
 
+
+    ## @brief Constructor of ScriptAdapter
+    #
+    # @param self The caller object
+    # @param policy A user-implemented class inheriting from Policy.Policy
     def __init__(self, policy):
         self._policy = policy()
         print 'ScriptAdapter for policy ', policy, ' loaded'
 
+
+    ## @brief Asynchronously call Policy.configure()
+    #
+    # @param self The caller object
     def async_configure(self):
         _g_mutex.lock(ScriptAdapter._wrap_configure, self )
         
@@ -38,6 +53,14 @@ class ScriptAdapter :
         self._policy.configure()
         _g_mutex.unlock()
 
+
+    ## @brief Asynchronously call Policy.sort_queue()
+    #
+    # The queue is asked directly to the C++ sgpem::Scheduler
+    # singleton, via SWIG
+    #
+    # @param self The caller object
+    # @param event The event to pass to sort_queue
     def async_sort_queue(self, event):
         self._event = event
         _g_mutex.lock(ScriptAdapter._wrap_sort_queue, self)
@@ -52,6 +75,10 @@ class ScriptAdapter :
         self._policy.sort_queue(event, queue)
         _g_mutex.unlock()
 
+
+    ## @brief Asynchronously call Policy.is_preemptive()
+    #
+    # @param self The caller object
     def async_is_preemptive(self):
         _g_mutex.lock(ScriptAdapter._wrap_is_preemptive, self)
 
@@ -62,6 +89,10 @@ class ScriptAdapter :
         _ret_val = self._policy.is_preemptive()
         _g_mutex.unlock()
 
+    
+    ## @brief Asynchronously call Policy.get_time_slice()
+    #
+    # @param self The caller object
     def async_get_time_slice(self):
         _g_mutex.lock(ScriptAdapter._wrap_get_time_slice, self)
 

src/backend/pyloader/python_policy_manager.hh

@@ -33,13 +33,38 @@ namespace sgpem
   //class PolicyManager;
   class PythonPolicyManager;
 
+  /** \brief Manages Python user-implemented policies
+   * 
+   * This singleton manages the creation and destruction 
+   * of a Python policy.
+   */
   class SG_DLLEXPORT PythonPolicyManager : public PolicyManager
   {
   public:
+    /** \brief Returns a reference to the active policy.
+     *
+     * For the moment, it will sufficit to keep and return 
+     * just one Policy for PolicyManager. 
+     * In the next milestones it will be possible to manage 
+     * more than one, and to retrieve the correct Policy by 
+     * passing a unique ID.
+     */
     Policy& get_policy();
-    void init();
-    PyObject* get_py_dict();
 
+    /** \brief Initialize the Python interpreter.
+     *
+     * If the interpreter has already been initialized, it terminates it, cleanups old policies,
+     * and restarts it.
+     */
+    void init();
+
+      /** \brief Returns the singleton instance of 
+       * PythonPolicyManager.
+       * 
+       * Please note that the first time you'll request 
+       * it, it will be still uninitialized.
+       * @see init()
+       */
     static PythonPolicyManager* const get_instance();	
 		
   private:
@@ -47,7 +72,10 @@ namespace sgpem
     PythonPolicyManager(const PythonPolicyManager&);
     PythonPolicyManager& operator=(const PythonPolicyManager&);
 
+    /** Singleton support. */
     static PythonPolicyManager* _instance;
+
+    /** The selected and active PyhonPolicy object. */
     std::auto_ptr<PythonPolicy>	_python_policy;
 
     bool _initialized;

src/builtin-policies/fcfs.py

@@ -16,18 +16,18 @@ class fcfs(Policy) :
     def sort_queue(self, event, queue):
         print 'Entering sort_queue'
         print queue.size()
+        print queue.get_item_at(0)
         print dir(queue.get_item_at(0))
         for i in range(0, queue.size()):
             ss = queue.get_item_at(i)
             print ss.get_schedulable().get_name()
-        cmpf = lambda a, b: \
-            a.get_schedulable().get_arrival_time() < \
-            b.get_schedulable().get_arrival_time()
-        try:
-            self.sort(queue,cmpf)
-        except:
-            print "Unexpected error:", sys.exc_info()[0]
-            raise
-        for i in range(0, queue.size()):
-            ss = queue.get_item_at(i)
-            print ss.get_schedulable().get_name()
+        # Uncomment this to try the qsort algorithm with FCFS
+        #cmpf = lambda a, b: \
+        #    a.get_schedulable().get_arrival_time() < \
+        #    b.get_schedulable().get_arrival_time()
+        #try:
+        #    self.sort(queue,cmpf)
+        #except:
+        #    print "Unexpected error:", sys.exc_info()[0]
+        #    raise
+