Added 'scheduler' decorator to register schedulers and their parameters

simso/schedulers/__init__.py

+# List of all schedulers that have been declared using
+# the @scheduler decorator.
+__loaded_schedulers = []
+
+# Decorator used to register a scheduler to be returned by get_declared_schedulers()
+def scheduler(name, **kwargs):
+	"""
+	Decorator used to register a scheduler to be returned by get_declared_schedulers().
+	Mandatory arguments : 
+		name : the complete name of the scheduler (ex : simso.schedulers.EDF)
+	Optional keyword arguments : 
+		display_name : name to be shown to the user
+		required_fields : list of required fields for this scheduler to work correctly.
+			It should be a dict with the following keys : 
+				name: name of the field
+				type: type of the field
+				default: default value of the field
+		required_task_fields : list of required fields for this scheduler's tasks
+			to work correctly. Same format as required_fields
+		required_proc_fields : list of required fields for this scheduler's processors
+			to work correctly. Same format as required_fields
+				
+	The list of registered schedulers is mostly used in graphical interfaces to auto-detect
+	the exposed schedulers.
+	"""
+	required_fields = kwargs['required_fields'] if 'required_fields' in kwargs else []
+	task_f = kwargs['required_task_fields'] if 'required_task_fields' in kwargs else []
+	proc_f = kwargs['required_proc_fields'] if 'required_proc_fields' in kwargs else []
+	display_name = kwargs['display_name'] if 'display_name' in kwargs else name
+	def f(klass):
+		# Note : 
+		# We didn't include this data into the classes because it didn't work
+		# properly with inheritance.
+		# klass.simso_name = name
+		# klass.simso_required_fields = required_fields
+		# klass.simso_required_task_fields = task_f
+		# klass.simso_required_proc_fields = proc_f
+		__loaded_schedulers.append({
+			'name': name,
+			'display_name': display_name,
+			'required_fields': required_fields,
+			'required_task_fields': task_f,
+			'required_proc_fields': proc_f
+		})
+		return klass
+		
+	return f
+
+def get_loaded_schedulers():
+	return __loaded_schedulers
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