--Copyright:      Matra Datavision 1992,1993

-- File:          OSD_Protection.cdl
-- Created:       Tue 18 1992
-- Author:        Stephan GARNAUD (ARM)
--                <sga@sparc4>



class Protection from OSD 

  ---Purpose: This  class provides data to manage file protection
  --  Example:These rights are treated in a system dependent manner :
  --          On UNIX you have User,Group and Other rights
  --          On VMS  you have Owner,Group,World and System rights
  --          An automatic conversion is done between OSD and UNIX/VMS.
  --           
  --          OSD	VMS	UNIX
  --          User     Owner   User
  --          Group    Group   Group
  --          World    World   Other
  --          System   System  (combined with Other)
  -- 
  --          When you use System protection on UNIX you must know that
  --          Other rights and System rights are inclusively "ORed". 
  --          So Other with only READ access and System with WRITE access
  --          will produce on UNIX Other with READ and WRITE access.
  --
  --          This choice comes from the fact that ROOT can't be considered
  --          as member of the group nor as user. So it is considered as Other.


 uses SingleProtection, AsciiString from TCollection


 is
  Create returns Protection;
   ---Purpose: Initializes global access rights as follows
   --
   --          User   : Read Write
   --          System : Read Write
   --          Group  : Read
   --          World  : Read
   ---Level: Public
  
  Create (System , 
    User , Group , World : SingleProtection) returns Protection;
    ---Purpose: Sets values of fields
    ---Level: Public

  Values (me : in out; 
    System , User , Group , World : out SingleProtection) is static;
    ---Purpose: Retrieves values of fields
    ---Level: Public

  SetValues (me : in out;  
    System , User , Group , World : SingleProtection) is static;
    ---Purpose: Sets values of fields
    ---Level: Public

  SetSystem(me : in out; priv : SingleProtection) is static;
    ---Purpose: Sets protection of 'System'
    ---Level: Public

  SetUser(me : in out; priv : SingleProtection) is static;
    ---Purpose: Sets protection of 'User'
    ---Level: Public

  SetGroup(me : in out; priv : SingleProtection) is static;
    ---Purpose: Sets protection of 'Group'
    ---Level: Public

  SetWorld(me : in out; priv : SingleProtection) is static;
    ---Purpose: Sets protection of 'World'
    ---Level: Public

  System(me ) returns SingleProtection is static;
    ---Purpose: Gets protection of 'System'
    ---Level: Public

  User(me ) returns SingleProtection is static;
    ---Purpose: Gets protection of 'User'
    ---Level: Public

  Group(me ) returns SingleProtection is static;
    ---Purpose: Gets protection of 'Group'
    ---Level: Public

  World(me ) returns SingleProtection is static;
    ---Purpose: Gets protection of 'World'
    ---Level: Public

  Internal (me) returns Integer  is static private;
    ---Purpose: Returns System dependent access rights
    --          this is a private method.
    ---Level: Public

  Add (me : in out ;
    aProt : in out SingleProtection ;aRight : SingleProtection) is static;
    ---Purpose: Add a right to a single protection.
    --          ex: aProt = RWD
    --              me.Add(aProt,X)  ->  aProt = RWXD
    ---Level: Public

  Sub (me : in out ;
    aProt : in out SingleProtection ;aRight : SingleProtection) is static;
   ---Purpose: Subtract a right to a single protection.
   --           ex: aProt = RWD
   --               me.Sub(aProt,RW) ->  aProt = D
   --               But me.Sub(aProt,RWX) is also valid and gives same result.
   ---Level: Public


 fields
  s : SingleProtection;  -- System right
  u : SingleProtection;  -- User right
  g : SingleProtection;  -- Group right
  w : SingleProtection;  -- World right

friends class FileNode, class File, class Directory

end Protection from OSD;