------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                                 F M A P                                  --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--            Copyright (C) 2001, Free Software Foundation, Inc.            --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT 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  distributed with GNAT;  see file COPYING.  If not, write --
-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
-- MA 02111-1307, USA.                                                      --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with GNAT.OS_Lib; use GNAT.OS_Lib;
with Namet;       use Namet;
with Opt;         use Opt;
with Osint;       use Osint;
with Output;      use Output;
with Table;

with Unchecked_Conversion;

with GNAT.HTable;

package body Fmap is

   subtype Big_String is String (Positive);
   type Big_String_Ptr is access all Big_String;

   function To_Big_String_Ptr is new Unchecked_Conversion
     (Source_Buffer_Ptr, Big_String_Ptr);

   type Mapping is record
      Uname : Unit_Name_Type;
      Fname : File_Name_Type;
   end record;

   package File_Mapping is new Table.Table (
     Table_Component_Type => Mapping,
     Table_Index_Type     => Int,
     Table_Low_Bound      => 0,
     Table_Initial        => 1_000,
     Table_Increment      => 1_000,
     Table_Name           => "Fmap.File_Mapping");
   --  Mapping table to map unit names to file names.

   package Path_Mapping is new Table.Table (
     Table_Component_Type => Mapping,
     Table_Index_Type     => Int,
     Table_Low_Bound      => 0,
     Table_Initial        => 1_000,
     Table_Increment      => 1_000,
     Table_Name           => "Fmap.Path_Mapping");
   --  Mapping table to map file names to path names

   type Header_Num is range 0 .. 1_000;

   function Hash (F : Unit_Name_Type) return Header_Num;
   --  Function used to compute hash of unit name

   No_Entry : constant Int := -1;
   --  Signals no entry in following table

   package Unit_Hash_Table is new GNAT.HTable.Simple_HTable (
     Header_Num => Header_Num,
     Element    => Int,
     No_Element => No_Entry,
     Key        => Unit_Name_Type,
     Hash       => Hash,
     Equal      => "=");
   --  Hash table to map unit names to file names. Used in conjunction with
   --  table File_Mapping above.

   package File_Hash_Table is new GNAT.HTable.Simple_HTable (
     Header_Num => Header_Num,
     Element    => Int,
     No_Element => No_Entry,
     Key        => File_Name_Type,
     Hash       => Hash,
     Equal      => "=");
   --  Hash table to map file names to path names. Used in conjunction with
   --  table Path_Mapping above.

   Last_In_Table : Int := 0;

   ---------------------
   -- Add_To_File_Map --
   ---------------------

   procedure Add_To_File_Map
     (Unit_Name : Unit_Name_Type;
      File_Name : File_Name_Type;
      Path_Name : File_Name_Type)
   is
   begin
      File_Mapping.Increment_Last;
      Unit_Hash_Table.Set (Unit_Name, File_Mapping.Last);
      File_Mapping.Table (File_Mapping.Last) :=
        (Uname => Unit_Name, Fname => File_Name);
      Path_Mapping.Increment_Last;
      File_Hash_Table.Set (File_Name, Path_Mapping.Last);
      Path_Mapping.Table (Path_Mapping.Last) :=
        (Uname => Unit_Name, Fname => Path_Name);
   end Add_To_File_Map;

   ----------
   -- Hash --
   ----------

   function Hash (F : Unit_Name_Type) return Header_Num is
   begin
      return Header_Num (Int (F) rem Header_Num'Range_Length);
   end Hash;

   ----------------
   -- Initialize --
   ----------------

   procedure Initialize (File_Name : String) is
      Src : Source_Buffer_Ptr;
      Hi  : Source_Ptr;
      BS  : Big_String_Ptr;
      SP  : String_Ptr;

      First : Positive := 1;
      Last  : Natural  := 0;

      Uname : Unit_Name_Type;
      Fname : Name_Id;
      Pname : Name_Id;

      The_Mapping : Mapping;

      procedure Empty_Tables;
      --  Remove all entries in case of incorrect mapping file

      procedure Get_Line;
      --  Get a line from the mapping file

      procedure Report_Truncated;
      --  Report a warning when the mapping file is truncated
      --  (number of lines is not a multiple of 3).

      ------------------
      -- Empty_Tables --
      ------------------

      procedure Empty_Tables is
      begin
         Unit_Hash_Table.Reset;
         File_Hash_Table.Reset;
         Path_Mapping.Set_Last (0);
         File_Mapping.Set_Last (0);
         Last_In_Table := 0;
      end Empty_Tables;

      --------------
      -- Get_Line --
      --------------

      procedure Get_Line is
         use ASCII;

      begin
         First := Last + 1;

         --  If not at the end of file, skip the end of line

         while First < SP'Last
           and then (SP (First) = CR
                     or else SP (First) = LF
                     or else SP (First) = EOF)
         loop
            First := First + 1;
         end loop;

         --  If not at the end of file, find the end of this new line

         if First < SP'Last and then SP (First) /= EOF then
            Last := First;

            while Last < SP'Last
              and then SP (Last + 1) /= CR
              and then SP (Last + 1) /= LF
              and then SP (Last + 1) /= EOF
            loop
               Last := Last + 1;
            end loop;

         end if;
      end Get_Line;

      ----------------------
      -- Report_Truncated --
      ----------------------

      procedure Report_Truncated is
      begin
         if not Quiet_Output then
            Write_Str ("warning: mapping file """);
            Write_Str (File_Name);
            Write_Line (""" is truncated");
         end if;
      end Report_Truncated;

   --  Start of procedure Initialize

   begin
      Empty_Tables;
      Name_Len := File_Name'Length;
      Name_Buffer (1 .. Name_Len) := File_Name;
      Read_Source_File (Name_Enter, 0, Hi, Src, Config);

      if Src = null then
         if not Quiet_Output then
            Write_Str ("warning: could not read mapping file """);
            Write_Str (File_Name);
            Write_Line ("""");
         end if;

      else
         BS := To_Big_String_Ptr (Src);
         SP := BS (1 .. Natural (Hi))'Unrestricted_Access;

         loop
            --  Get the unit name

            Get_Line;

            --  Exit if end of file has been reached

            exit when First > Last;

            pragma Assert (Last >= First + 2);
            pragma Assert (SP (Last - 1) = '%');
            pragma Assert (SP (Last) = 's' or else SP (Last) = 'b');

            Name_Len := Last - First + 1;
            Name_Buffer (1 .. Name_Len) := SP (First .. Last);
            Uname := Name_Find;

            --  Get the file name

            Get_Line;

            --  If end of line has been reached, file is truncated

            if First > Last then
               Report_Truncated;
               Empty_Tables;
               return;
            end if;

            Name_Len := Last - First + 1;
            Name_Buffer (1 .. Name_Len) := SP (First .. Last);
            Fname := Name_Find;

            --  Get the path name

            Get_Line;

            --  If end of line has been reached, file is truncated

            if First > Last then
               Report_Truncated;
               Empty_Tables;
               return;
            end if;

            Name_Len := Last - First + 1;
            Name_Buffer (1 .. Name_Len) := SP (First .. Last);
            Pname := Name_Find;

            --  Check for duplicate entries

            if Unit_Hash_Table.Get (Uname) /= No_Entry then
               if not Quiet_Output then
                  Write_Str ("warning: duplicate entry """);
                  Write_Str (Get_Name_String (Uname));
                  Write_Str (""" in mapping file """);
                  Write_Str (File_Name);
                  Write_Line ("""");
                  The_Mapping :=
                    File_Mapping.Table (Unit_Hash_Table.Get (Uname));
                  Write_Line (Get_Name_String (The_Mapping.Uname));
                  Write_Line (Get_Name_String (The_Mapping.Fname));
               end if;

               Empty_Tables;
               return;
            end if;

            if File_Hash_Table.Get (Fname) /= No_Entry then
               if not Quiet_Output then
                  Write_Str ("warning: duplicate entry """);
                  Write_Str (Get_Name_String (Fname));
                  Write_Str (""" in mapping file """);
                  Write_Str (File_Name);
                  Write_Line ("""");
                  The_Mapping :=
                    Path_Mapping.Table (File_Hash_Table.Get (Fname));
                  Write_Line (Get_Name_String (The_Mapping.Uname));
                  Write_Line (Get_Name_String (The_Mapping.Fname));
               end if;

               Empty_Tables;
               return;
            end if;

            --  Add the mappings for this unit name

            Add_To_File_Map (Uname, Fname, Pname);
         end loop;
      end if;

      --  Record the length of the two mapping tables

      Last_In_Table := File_Mapping.Last;

   end Initialize;

   ----------------------
   -- Mapped_File_Name --
   ----------------------

   function Mapped_File_Name (Unit : Unit_Name_Type) return File_Name_Type is
      The_Index : constant Int := Unit_Hash_Table.Get (Unit);

   begin
      if The_Index = No_Entry then
         return No_File;
      else
         return File_Mapping.Table (The_Index).Fname;
      end if;
   end Mapped_File_Name;

   ----------------------
   -- Mapped_Path_Name --
   ----------------------

   function Mapped_Path_Name (File : File_Name_Type) return File_Name_Type is
      Index : Int := No_Entry;

   begin
      Index := File_Hash_Table.Get (File);

      if Index = No_Entry then
         return No_File;
      else
         return Path_Mapping.Table (Index).Fname;
      end if;
   end Mapped_Path_Name;

   -------------------------
   -- Update_Mapping_File --
   -------------------------

   procedure Update_Mapping_File (File_Name : String) is
      File : File_Descriptor;

      procedure Put_Line (Name : Name_Id);
      --  Put Name as a line in the Mapping File

      --------------
      -- Put_Line --
      --------------

      procedure Put_Line (Name : Name_Id) is
         N_Bytes : Integer;
      begin
         Get_Name_String (Name);
         Name_Len := Name_Len + 1;
         Name_Buffer (Name_Len) := ASCII.LF;
         N_Bytes := Write (File, Name_Buffer (1)'Address, Name_Len);

         if N_Bytes < Name_Len then
            Fail ("disk full");
         end if;

      end Put_Line;

   --  Start of Update_Mapping_File

   begin

      --  Only Update if there are new entries in the mappings

      if Last_In_Table < File_Mapping.Last then

         --  If the tables have been emptied, recreate the file.
         --  Otherwise, append to it.

         if Last_In_Table = 0 then
            declare
               Discard : Boolean;

            begin
               Delete_File (File_Name, Discard);
            end;

            File := Create_File (File_Name, Binary);

         else
            File := Open_Read_Write (Name => File_Name, Fmode => Binary);
         end if;

         if File /= Invalid_FD then
            if Last_In_Table > 0 then
               Lseek (File, 0, Seek_End);
            end if;

            for Unit in Last_In_Table + 1 .. File_Mapping.Last loop
               Put_Line (File_Mapping.Table (Unit).Uname);
               Put_Line (File_Mapping.Table (Unit).Fname);
               Put_Line (Path_Mapping.Table (Unit).Fname);
            end loop;

            Close (File);

         elsif not Quiet_Output then
            Write_Str ("warning: could not open mapping file """);
            Write_Str (File_Name);
            Write_Line (""" for update");
         end if;

      end if;
   end Update_Mapping_File;

end Fmap;
