(* M2Preprocess.mod provides a mechanism to invoke the C preprocessor.

Copyright (C) 2001-2025 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.

This file is part of GNU Modula-2.

GNU Modula-2 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 3, or (at your option)
any later version.

GNU Modula-2 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 GNU Modula-2; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  *)

IMPLEMENTATION MODULE M2Preprocess ;


FROM SYSTEM IMPORT WORD ;

FROM DynamicStrings IMPORT string, InitString, Mark, KillString, EqualArray, InitStringCharStar,
                           Dup, ConCat, ConCatChar, RIndex, Slice, Length ;

FROM choosetemp IMPORT make_temp_file ;
FROM pexecute IMPORT pexecute ;
FROM libc IMPORT system, exit, unlink, printf, atexit ;
FROM Lists IMPORT List, InitList, KillList, IncludeItemIntoList, ForeachItemInListDo ;
FROM FIO IMPORT StdErr, StdOut ;
FROM M2Printf IMPORT fprintf1 ;

FROM M2Options IMPORT Verbose, PPonly, GetObj, GetMD, GetMMD, GetCpp, GetMQ,
                      CppCommandLine, SaveTemps, GetSaveTempsDir, GetDumpDir,
                      GetM, GetMM ;

FROM NameKey IMPORT Name, MakeKey, KeyToCharStar, makekey ;


CONST
   Debugging = FALSE ;

VAR
   ListOfFiles: List ;


(*
   OnExitDelete - when the application finishes delete filename.
*)

PROCEDURE OnExitDelete (filename: String) : String ;
BEGIN
   IF filename # NIL
   THEN
      IF Debugging
      THEN
         printf ("scheduling removal: %s\n", string (filename))
      END ;
      IncludeItemIntoList (ListOfFiles, makekey (string (filename)))
   END ;
   RETURN filename
END OnExitDelete ;


(*
   RemoveFile - removes a single file, s.
*)

PROCEDURE RemoveFile (w: WORD) ;
VAR
   n: Name ;
BEGIN
   n := w ;
   IF Debugging
   THEN
      printf ("removing: %s\n", KeyToCharStar (n))
   END ;
   IF unlink (KeyToCharStar (n)) # 0
   THEN
   END
END RemoveFile ;


(*
   RemoveFiles -
*)

PROCEDURE RemoveFiles () : INTEGER ;
BEGIN
   ForeachItemInListDo (ListOfFiles, RemoveFile) ;
   RETURN 0
END RemoveFiles ;

(*
   Return the filename with no path.
*)

PROCEDURE GetFileName (Path: String) : String ;
VAR
   fstart: INTEGER ;
BEGIN
   fstart := RIndex(Path, '/', 0) ;
   IF fstart=-1
   THEN
      fstart := 0
   ELSE
      fstart := fstart + 1
   END ;
   RETURN Dup (Slice(Path, fstart, Length (Path)))
END GetFileName ;


(*
   MakeSaveTempsFileName - return a temporary file like
   "./filename.{def,mod}.m2i" in the current working directory unless
   SaveTempsDir = obj, when we put it in the dumpdir if that is specified
   (or fallback to '.' if not).
   We have to keep the original extension because that disambiguates .def
   and .mod files (otherwise, we'd need two 'preprocessed' extensions).
*)

PROCEDURE MakeSaveTempsFileName (filename: String) : String ;
BEGIN
   RETURN MakeSaveTempsFileNameExt (filename, InitString ('.m2i'))
END MakeSaveTempsFileName ;


(*
   MakeSaveTempsFileNameExt - creates and return the temporary filename.ext.
                              in the current working directory unless
                              SaveTempsDir = obj, when we put it in the dumpdir
                              if that is specified (or fallback to '.' if not).
*)

PROCEDURE MakeSaveTempsFileNameExt (filename, ext: String) : String ;
VAR
   NewName,
   DumpDir,
   NewDir : String ;
BEGIN
   NewName := ConCat (Dup (GetFileName (filename)), ext) ;
   NewDir := Dup (GetSaveTempsDir ()) ;
   DumpDir := Dup (GetDumpDir ()) ;
   IF Debugging
   THEN
      fprintf1 (StdOut, "newname: %s", NewName) ;
      fprintf1 (StdOut, " NewDir: %s", NewDir) ;
      fprintf1 (StdOut, " DumpDir: %s\n", DumpDir)
   END ;
   IF (NewDir#NIL) AND EqualArray (NewDir, 'obj') AND (DumpDir#NIL)
   THEN
      RETURN ConCat (DumpDir, NewName)
   ELSE
      RETURN ConCat (InitString ('./'), NewName)
   END ;
END MakeSaveTempsFileNameExt ;


(*
   BuildCommandLineExecute - build the cpp command line and execute the command and return
                             the tempfile containing the preprocessed source.
*)

PROCEDURE BuildCommandLineExecute (filename: String;
                                   topSource, deleteDep: BOOLEAN;
                                   command, outputdep: String) : String ;
VAR
   tempfile,
   commandLine: String ;
BEGIN
   commandLine := Dup (command) ;
   tempfile := NIL ;
   (* We support MD and MMD for the main file only, at present.  *)
   IF topSource OR PPonly
   THEN
      IF GetMD ()
      THEN
         tempfile := ConCat (InitString(' -MD '), outputdep)
      ELSIF GetMMD ()
      THEN
         tempfile := ConCat (InitString(' -MMD '), outputdep)
      END ;
      IF tempfile#NIL
      THEN
         commandLine := ConCat (Dup (commandLine), Dup (tempfile)) ;
         (* We can only add MQ if we already have an MD/MMD.  *)
         IF GetMQ () # NIL
         THEN
            tempfile := InitStringCharStar (GetMQ ()) ;
            commandLine := ConCat (Dup (commandLine), Dup (tempfile))
         END
      END
   END ;
   (* The output file depends on whether we are in stand-alone PP mode, and
      if an output file is specified.  *)
   tempfile := NIL ;
   IF PPonly
   THEN
      IF GetObj () # NIL
      THEN
         tempfile := InitStringCharStar (GetObj ())
      END
   ELSIF SaveTemps
   THEN
      tempfile := MakeSaveTempsFileName (filename)
   ELSE
      tempfile := InitStringCharStar (make_temp_file (KeyToCharStar (MakeKey('.m2i'))))
   END ;
   commandLine := ConCat (ConCatChar (Dup (commandLine), ' '), filename) ;
   IF tempfile # NIL
   THEN
      commandLine := ConCat (ConCat (Dup (commandLine),
                                     Mark (InitString(' -o '))), tempfile) ;
   END ;
   IF (outputdep # NIL) AND (Length (outputdep) > 0) AND (GetM () OR GetMM ())
   THEN
      commandLine := ConCat (commandLine, ConCat (Mark (InitString (' -MF ')),
                                                  outputdep)) ;
      IF deleteDep AND (NOT SaveTemps)
      THEN
         outputdep := OnExitDelete (outputdep)
      END
   END ;
   (* use pexecute in the future
      res := pexecute(string(Slice(commandLine, 0, Index(commandLine, ' ', 0))), etc etc );  *)
   (* for now we'll use system *)
   IF Verbose
   THEN
      fprintf1 (StdOut, "preprocess: %s\n", commandLine)
   END ;
   IF system (string (commandLine)) # 0
   THEN
      fprintf1 (StdErr, 'C preprocessor failed when preprocessing %s\n', filename) ;
      exit (1)
   END ;
   commandLine := KillString (commandLine) ;
   IF SaveTemps
   THEN
      RETURN tempfile
   ELSE
      RETURN OnExitDelete (tempfile)
   END
END BuildCommandLineExecute ;


(*
   PreprocessModule - preprocess a file, filename, returning the new filename
                      of the preprocessed file.
                      Preprocessing will only occur if requested by the user.
                      If no preprocessing was requested then filename is returned.
                      If preprocessing occurs then a temporary file is created
                      and its name is returned.
                      All temporary files will be deleted when the compiler exits.
                      outputdep is the filename which will contain the dependency
                      info if -M, -MM is provided.  outputdep can be NIL in which case
                      it is ignored.
*)

PROCEDURE PreprocessModule (filename: String;
                            topSource, deleteDep: BOOLEAN;
                            outputDep: String) : String ;
VAR
   command: String ;
BEGIN
   IF GetCpp ()
   THEN
      command := CppCommandLine () ;
      IF (command = NIL) OR EqualArray (command, '')
      THEN
         RETURN Dup (filename)
      END ;
      command := BuildCommandLineExecute (filename, topSource, deleteDep,
                                          command, outputDep) ;
      IF command = NIL
      THEN
         RETURN filename
      ELSE
         RETURN command
      END
   ELSE
      RETURN Dup (filename)
   END
END PreprocessModule ;


BEGIN
   InitList (ListOfFiles) ;
   IF atexit (RemoveFiles) # 0
   THEN
      HALT
   END
END M2Preprocess.