File : src/aws-resources.ads


------------------------------------------------------------------------------
--                              Ada Web Server                              --
--                                                                          --
--                         Copyright (C) 2002-2003                          --
--                                ACT-Europe                                --
--                                                                          --
--  Authors: Dmitriy Anisimkov - Pascal Obry                                --
--                                                                          --
--  This library is free software; you can redistribute it and/or modify    --
--  it under the terms of the GNU General Public License as published by    --
--  the Free Software Foundation; either version 2 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       --
--  General Public License for more details.                                --
--                                                                          --
--  You should have received a copy of the GNU General Public License       --
--  along with this library; if not, write to the Free Software Foundation, --
--  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.          --
--                                                                          --
--  As a special exception, if other files instantiate generics from this   --
--  unit, or you link this unit with other files to produce an executable,  --
--  this  unit  does not  by itself cause  the resulting executable to be   --
--  covered by the GNU General Public License. This exception does not      --
--  however invalidate any other reasons why the executable file  might be  --
--  covered by the  GNU Public License.                                     --
------------------------------------------------------------------------------

--  $Id: aws-resources.ads,v 1.8 2003/07/03 16:58:04 obry Exp $

with Ada.Calendar;
with Ada.Streams;
with Ada.Unchecked_Deallocation;

package AWS.Resources is

   use Ada.Streams;

   Resource_Error : exception;

   type File_Type is limited private;

   subtype Content_Length_Type is Stream_Element_Offset;

   Undefined_Length : constant Content_Length_Type;
   --  Undefined length could be used when we do not know the message stream
   --  length at the start of transfer. The end of message could be determined
   --  by the chunked transfer-encoding in the HTTP/1.1, or by the closing
   --  connection in the HTTP/1.0.

   procedure Open
     (File :    out File_Type;
      Name : in     String;
      Form : in     String    := "");
   --  Open file in mode In_File. Only reading from the file is supported.
   --  This procedure open the in-memory file if present, otherwise the file
   --  on disk is opened.

   procedure Close (Resource : in out File_Type);
   --  Close the file.

   procedure Read
     (Resource : in out File_Type;
      Buffer   :    out Stream_Element_Array;
      Last     :    out Stream_Element_Offset);
   --  Returns a set of bytes from the file.

   procedure Get_Line
     (Resource  : in out File_Type;
      Buffer    :    out String;
      Last      :    out Natural);
   --  Returns a line from the file. A line is a set of character terminated
   --  by ASCII.LF (UNIX style EOF) or ASCII.CR+ASCII.LF (DOS style EOF).

   function End_Of_File (Resource : in File_Type) return Boolean;
   --  Returns true if there is no more data to read.

   function LF_Terminated (Resource : in File_Type) return Boolean;
   --  Returns True if last line returned by Get_Line was terminated with a LF
   --  or CR+LF on DOS based systems.

   function Size (Resource : in File_Type) return Content_Length_Type;
   --  Returns the size (in bytes) of the resource. If the size of the
   --  resource is not defined, the routine Size returns Undefined_Length
   --  value.

   function Is_Regular_File
     (Name : in String)
      return Boolean;
   --  Returns True if Filename is a regular file and is readable. Checks first
   --  for in memory file then for disk file.

   function File_Size
     (Name   : in String)
      return Stream_Element_Offset;
   --  Returns Filename's size in bytes. Checks first for in memory file
   --  then for disk file.

   function File_Timestamp
     (Name : in String)
      return Ada.Calendar.Time;
   --  Get the time for last modification to a file in UTC/GMT. Checks first
   --  for in memory file then for disk file.

private

   Undefined_Length : constant Content_Length_Type := -1;

   type File_Tagged is abstract tagged limited record
      LFT : Boolean; -- LF terminated state
   end record;

   --  Abstract file, operations below must be implemented. The goal here is
   --  to abstract the file location. Currently there is two implementations,
   --  one for files on a hard disk and files in memory (array of bytes).

   type File_Type is access all File_Tagged'Class;

   function End_Of_File
     (Resource : in File_Tagged)
      return Boolean
      is abstract;

   procedure Read
     (Resource : in out File_Tagged;
      Buffer   :    out Stream_Element_Array;
      Last     :    out Stream_Element_Offset)
      is abstract;

   function Size
     (Resource : in File_Tagged)
      return Stream_Element_Offset
      is abstract;

   procedure Close (File : in out File_Tagged)
      is abstract;

   procedure Free is
      new Ada.Unchecked_Deallocation (Resources.File_Tagged'Class, File_Type);

end AWS.Resources;