-- -- Copyright (c) 2009, -- Reto Buerki, Adrian-Ken Rueegsegger -- secunet SwissIT AG -- -- This file is part of Alog. -- -- Alog is free software; you can redistribute it and/or modify -- it under the terms of the GNU Lesser General Public License as published -- by the Free Software Foundation; either version 2.1 of the License, or -- (at your option) any later version. -- -- Alog is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU Lesser General Public License for more details. -- -- You should have received a copy of the GNU Lesser General Public License -- along with Alog; if not, write to the Free Software -- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, -- MA 02110-1301 USA -- with Ada.Exceptions; with Ada.Finalization; with Alog.Facilities;
with Alog.Transforms;
with Alog.Tasked_Logger;
with Alog.Protected_Containers;
-- Active Logger instance. This logger is an active object and implements -- concurrent, asynchronous logging. It provides the same functionality as the -- 'simple' logger. package Alog.Active_Logger is
type Instance (Init : Boolean) is tagged limited private;
-- Active logger instance. Incoming messages (via Log_Message) are put into -- a request queue. This queue is consumed by a logging task. Exceptions -- that might be thrown while logging are saved into a map on a per-caller -- basis. type Handle is access all Instance;
-- Handle to active logger type. procedure Attach_Facility
(Logger : in out Instance;
Facility : Facilities.Handle);
-- Attach a facility to logger instance. procedure Attach_Default_Facility (Logger : in out Instance);
-- Attach default facility with name Default_Facility_Name to logger -- instance. If the default facility is already attached do nothing. procedure Detach_Facility
(Logger : in out Instance;
Name : String);
-- Detach a facility with name 'Name' from logger instance. If the facility -- is not found a Facility_Not_Found exception is raised. procedure Detach_Default_Facility (Logger : in out Instance);
-- Detach default facility with name Default_Facility_Name from logger -- instance. If the default facility is not attached do nothing. function Facility_Count (Logger : Instance) return Natural;
-- Return number of attached facilites. procedure Update
(Logger : in out Instance;
Name : String;
Process : Tasked_Logger.Facility_Update_Handle);
-- Update a specific Facility identified by 'Name'. Call the 'Process' -- procedure to perform the update operation. procedure Iterate
(Logger : in out Instance;
Process : Tasked_Logger.Facility_Update_Handle);
-- Call 'Process' for all attached facilities. procedure Attach_Transform
(Logger : in out Instance;
Transform : Transforms.Handle);
-- Attach a transform to logger instance. procedure Detach_Transform
(Logger : in out Instance;
Name : String);
-- Detach a transform with name 'Name' from logger instance. If the -- transform is not found a Transform_Not_Found exception is raised. function Transform_Count (Logger : Instance) return Natural;
-- Return number of attached transforms. procedure Clear (Logger : in out Instance);
-- Clear logger instance. Detach and teardown all attached facilities and -- transforms. procedure Log_Message
(Logger : in out Instance;
Source : String := "";
Level : Log_Level;
Msg : String);
-- Log the given message asynchronously. The message is put into a log -- request queue which is continuously consumed by a logging task. -- -- Prior to actually processing the given log message the policy database is -- inquired if the log message with given source and level should be logged. -- -- This procedure is *safe* to call from protected actions (e.g. from an -- entry call statement or rendezvous). function Get_Queue_Length (Logger : Instance) return Natural;
-- Returns the number of currently queued log messages. procedure Shutdown
(Logger : in out Instance;
Flush : Boolean := True);
-- Shutdown the active logger. This procedure must be called in order for -- the logger task to be terminated properly. If 'Flush' is set to True the -- procedure will wait for all queued messages to be logged. function Is_Terminated (Logger : Instance) return Boolean;
-- Returns True if active logger shutdown sequence is complete. procedure All_Done (Logger : in out Instance);
-- This procedure blocks until all queued logging requests have been -- consumed. procedure Get_Last_Exception
(Logger : in out Instance;
Occurrence : out Ada.Exceptions.Exception_Occurrence);
-- Return last known Exception_Occurrence for caller. If no exception -- occured Null_Occurrence is returned. type Shutdown_Helper (Logger : not null access Instance) is private;
-- This helper will call Shutdown on the logger given as discriminant when -- it goes out of scope. This relieves the user from having to excplicitly -- call shutdown on an instance of Alog active logger when wanting to -- terminate. Users must make sure to declare any shutdown helper in a -- smaller scope than the active logger on which the helper supposed to -- work. private procedure Check_Exception (Logger : in out Instance);
-- Check if call to backend raised an exception. Explicitly reraise if an -- exception occured; do nothing otherwise. task type Logging_Task (Parent : not null access Instance);
-- This task takes logging requests from the parent's message queue and -- logs them using the parent's backend logger. protected type Trigger_Type is
procedure Shutdown; entry Stop; private Shutdown_Requested : Boolean := False;
end Trigger_Type; -- This trigger is used to terminate the logger task by means of ATC. type Instance (Init : Boolean) is tagged limited record
Logger_Task : Logging_Task (Parent => Instance'Access); Backend : Tasked_Logger.Instance (Init); Message_Queue : Protected_Containers.Log_Request_List; Trigger : Trigger_Type;
end record;
type Shutdown_Helper (Logger : not null access Instance) is
new Ada.Finalization.Controlled with null record;
overriding procedure Finalize (Helper : in out Shutdown_Helper);
-- Call shutdown on the active logger instance specified as discriminat. end Alog.Active_Logger;