adtlog.pas.mcp

(* This file is a part of the PascalAdt library, which provides
   commonly used algorithms and data structures for the fpc and
   Delphi compilers.
   
   Copyright (C) 2004 by Lukasz Czajka
   
   This library 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.
   
   This library 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 this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   02110-1301 USA *)

unit adtlog;

{ This unit provides logging facilities. All routines here work only
  when compiled in the debug mode, otherwise they do nothing. }

interface

uses
   SysUtils, Classes;

&include adtdefs.inc

const
   pascal_adt_log_file_name = 'pascaladt.log';

{ sets <newstream> to be the current logging stream. The old logging
  stream is destroyed; }
procedure SetLogStream(newstream : TStream);
{ Writes a specified message to the logging stream; appends newline; }
procedure WriteLogStream(const msg : String);
{ Opens pascal_adt_log_file_name as a log stream. Makes a backup if
  this file exists. Destroys the previous stream. }
procedure OpenLogStream;


implementation

var
   logStream : TStream;

{ this function is not present in Delphi }
procedure WriteByte(b : Byte);
begin
   logStream.Write(b, 1);
end;

procedure SetLogStream(newstream : TStream);
begin
   if newstream <> nil then
   begin
      logStream.Free;
      logStream := newstream;
   end;
end;

procedure WriteLogStream(const msg : string);
begin
   if logStream <> nil then
   begin
      with logStream do
      begin
         Write((@msg[1])^, Length(msg));
         {$ifdef PASCAL_ADT_WINDOWS }
         WriteByte(13);
         {$endif }
         WriteByte(10);
      end;
   end;
end;

procedure OpenLogStream;
begin
   logStream.Free;
   
   if FileExists(pascal_adt_log_file_name) then
   begin
      if FileExists(pascal_adt_log_file_name + '.bak') then
         DeleteFile(pascal_adt_log_file_name + '.bak');
      RenameFile(pascal_adt_log_file_name, pascal_adt_log_file_name + '.bak');
   end;
   
   logStream := TFileStream.Create(pascal_adt_log_file_name,
                                   fmCreate);
end;


initialization
   logStream := nil;
{$ifdef DEBUG_PASCAL_ADT }      
   OpenLogStream;
{$endif DEBUG_PASCAL_ADT }   
   
finalization
   
   logStream.Free;
end.