------------------------------------------------------------------------------
--                              Ada Web Server                              --
--                                                                          --
--                     Copyright (C) 2007-2016, AdaCore                     --
--                                                                          --
--  This library is free software;  you can redistribute it and/or modify   --
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------------------------------------------------------------------------------

--  An ready-to-use implementation of the stream API where the stream content
--  is read from a pipe.

with GNAT.OS_Lib;

private with Ada.Strings.Unbounded;
private with GNAT.Expect;

package AWS.Resources.Streams.Pipe is

   use GNAT;

   type Stream_Type is new Streams.Stream_Type with private;

   type On_Error_Callback is
     access procedure (Status : Integer; Error : String);

   procedure Open
     (Pipe     : out Stream_Type;
      Command  : String;
      Args     : OS_Lib.Argument_List;
      Timeout  : Integer := 10_000;
      On_Error : On_Error_Callback := null);
   --  Open the pipe and connect it to the given command's output. Args are
   --  passed to the command. Timeout is given in milliseconds and corresponds
   --  to the time waiting for output data before timeout. This timeout must be
   --  adjusted to be compatible to the output activity of the Command process.

   overriding function End_Of_File (Resource : Stream_Type) return Boolean;

   overriding procedure Read
     (Resource : in out Stream_Type;
      Buffer   : out Stream_Element_Array;
      Last     : out Stream_Element_Offset);

   overriding procedure Close (Resource : in out Stream_Type);

   overriding procedure Reset (Resource : in out Stream_Type) is null;
   --  Does nothing as not supported on pipe streams

   overriding procedure Set_Index
     (Resource : in out Stream_Type;
      To       : Stream_Element_Offset) is null;
   --  Does nothing as not supported on pipe streams

private

   use Ada.Strings.Unbounded;

   type Stream_Type is new Streams.Stream_Type with record
      Pid      : Expect.Process_Descriptor;
      Timeout  : Integer;
      EOF      : Boolean;
      Buffer   : Unbounded_String;
      On_Error : On_Error_Callback;
   end record;

end AWS.Resources.Streams.Pipe;
