/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying

   file LICENSE.rst or https://cmake.org/licensing for details.  */

#include "cmDependsFortran.h"

#include <cassert>

#include <cstdlib>

#include <iostream>

#include <map>

#include <utility>

#include "cmsys/FStream.hxx"

#include "cmFortranParser.h" /* Interface to parser object.  */

#include "cmGeneratedFileStream.h"

#include "cmGlobalUnixMakefileGenerator3.h"

#include "cmList.h"

#include "cmLocalUnixMakefileGenerator3.h"

#include "cmMakefile.h"

#include "cmOutputConverter.h"

#include "cmStringAlgorithms.h"

#include "cmSystemTools.h"

#include "cmValue.h"

// TODO: Test compiler for the case of the mod file.  Some always

// use lower case and some always use upper case.  I do not know if any

// use the case from the source code.

static void cmFortranModuleAppendUpperLower(std::string const& mod,

                                            std::string& mod_upper,

                                            std::string& mod_lower)

{

  std::string::size_type ext_len = 0;

  if (cmHasLiteralSuffix(mod, ".mod") || cmHasLiteralSuffix(mod, ".sub")) {

    ext_len = 4;

  } else if (cmHasLiteralSuffix(mod, ".smod")) {

    ext_len = 5;

  }

  std::string const& name = mod.substr(0, mod.size() - ext_len);

  std::string const& ext = mod.substr(mod.size() - ext_len);

  mod_upper =

    cmStrCat(std::move(mod_upper), cmSystemTools::UpperCase(name), ext);

  mod_lower += mod;

}

class cmDependsFortranInternals

{

public:

  // The set of modules provided by this target.

  std::set<std::string> TargetProvides;

  // Map modules required by this target to locations.

  using TargetRequiresMap = std::map<std::string, std::string>;

  TargetRequiresMap TargetRequires;

  // Information about each object file.

  using ObjectInfoMap = std::map<std::string, cmFortranSourceInfo>;

  ObjectInfoMap ObjectInfo;

  cmFortranSourceInfo& CreateObjectInfo(std::string const& obj,

                                        std::string const& src)

  {

    auto i = this->ObjectInfo.find(obj);

    if (i == this->ObjectInfo.end()) {

      std::map<std::string, cmFortranSourceInfo>::value_type entry(

        obj, cmFortranSourceInfo());

      i = this->ObjectInfo.insert(entry).first;

      i->second.Source = src;

    }

    return i->second;

  }

};

cmDependsFortran::cmDependsFortran() = default;

cmDependsFortran::cmDependsFortran(cmLocalUnixMakefileGenerator3* lg)

  : cmDepends(lg)

  , Internal(new cmDependsFortranInternals)

{

  // Configure the include file search path.

  this->SetIncludePathFromLanguage("Fortran");

  // Get the list of definitions.

  cmMakefile* mf = this->LocalGenerator->GetMakefile();

  cmList definitions{ mf->GetDefinition("CMAKE_TARGET_DEFINITIONS_Fortran") };

  // translate i.e. FOO=BAR to FOO and add it to the list of defined

  // preprocessor symbols

  for (std::string def : definitions) {

    std::string::size_type assignment = def.find('=');

    if (assignment != std::string::npos) {

      def.resize(assignment);

    }

    this->PPDefinitions.insert(def);

  }

  this->CompilerId = mf->GetSafeDefinition("CMAKE_Fortran_COMPILER_ID");

  this->SModSep = mf->GetSafeDefinition("CMAKE_Fortran_SUBMODULE_SEP");

  this->SModExt = mf->GetSafeDefinition("CMAKE_Fortran_SUBMODULE_EXT");

}

cmDependsFortran::~cmDependsFortran() = default;

bool cmDependsFortran::WriteDependencies(std::set<std::string> const& sources,

                                         std::string const& obj,

                                         std::ostream& /*makeDepends*/,

                                         std::ostream& /*internalDepends*/)

{

  // Make sure this is a scanning instance.

  if (sources.empty() || sources.begin()->empty()) {

    cmSystemTools::Error("Cannot scan dependencies without a source file.");

    return false;

  }

  if (obj.empty()) {

    cmSystemTools::Error("Cannot scan dependencies without an object file.");

    return false;

  }

  cmFortranCompiler fc;

  fc.Id = this->CompilerId;

  fc.SModSep = this->SModSep;

  fc.SModExt = this->SModExt;

  bool okay = true;

  for (std::string const& src : sources) {

    // Get the information object for this source.

    cmFortranSourceInfo& info = this->Internal->CreateObjectInfo(obj, src);

    // Create the parser object. The constructor takes info by reference,

    // so we may look into the resulting objects later.

    cmFortranParser parser(fc, this->IncludePath, this->PPDefinitions, info);

    // Push on the starting file.

    cmFortranParser_FilePush(&parser, src.c_str());

    // Parse the translation unit.

    if (cmFortran_yyparse(parser.Scanner) != 0) {

      // Failed to parse the file.  Report failure to write dependencies.

      okay = false;

      /* clang-format off */

      std::cerr <<

        "warning: failed to parse dependencies from Fortran source "

        "'" << src << "': " << parser.Error << std::endl

        ;

      /* clang-format on */

    }

  }

  return okay;

}

bool cmDependsFortran::Finalize(std::ostream& makeDepends,

                                std::ostream& internalDepends)

{

  // Prepare the module search process.

  if (!this->LocateModules()) {

    return false;

  }

  // Get the directory in which stamp files will be stored.

  std::string const& stamp_dir = this->TargetDirectory;

  // Get the directory in which module files will be created.

  cmMakefile* mf = this->LocalGenerator->GetMakefile();

  std::string mod_dir =

    mf->GetSafeDefinition("CMAKE_Fortran_TARGET_MODULE_DIR");

  if (mod_dir.empty()) {

    mod_dir = this->LocalGenerator->GetCurrentBinaryDirectory();

  }

  // ATTENTION Before 4.0 the property name was misspelled.

  // Check the correct name first and than the old name.

  bool building_intrinsics =

    !mf->GetSafeDefinition("CMAKE_Fortran_TARGET_BUILDING_INTRINSIC_MODULES")

       .empty() ||

    !mf->GetSafeDefinition("CMAKE_Fortran_TARGET_BUILDING_INSTRINSIC_MODULES")

       .empty();

  // Actually write dependencies to the streams.

  using ObjectInfoMap = cmDependsFortranInternals::ObjectInfoMap;

  ObjectInfoMap const& objInfo = this->Internal->ObjectInfo;

  for (auto const& i : objInfo) {

    if (!this->WriteDependenciesReal(i.first, i.second, mod_dir, stamp_dir,

                                     makeDepends, internalDepends,

                                     building_intrinsics)) {

      return false;

    }

  }

  // Store the list of modules provided by this target.

  std::string fiName = cmStrCat(this->TargetDirectory, "/fortran.internal");

  cmGeneratedFileStream fiStream(fiName);

  fiStream << "# The fortran modules provided by this target.\n";

  fiStream << "provides\n";

  std::set<std::string> const& provides = this->Internal->TargetProvides;

  for (std::string const& i : provides) {

    fiStream << ' ' << i << '\n';

  }

  // Create a script to clean the modules.

  if (!provides.empty()) {

    std::string fcName =

      cmStrCat(this->TargetDirectory, "/cmake_clean_Fortran.cmake");

    cmGeneratedFileStream fcStream(fcName);

    fcStream << "# Remove fortran modules provided by this target.\n";

    fcStream << "FILE(REMOVE";

    for (std::string const& i : provides) {

      std::string mod_upper = cmStrCat(mod_dir, '/');

      std::string mod_lower = cmStrCat(mod_dir, '/');

      cmFortranModuleAppendUpperLower(i, mod_upper, mod_lower);

      std::string stamp = cmStrCat(stamp_dir, '/', i, ".stamp");

      fcStream << "\n"

                  "  \""

               << this->LocalGenerator->MaybeRelativeToCurBinDir(mod_lower)

               << "\"\n"

                  "  \""

               << this->LocalGenerator->MaybeRelativeToCurBinDir(mod_upper)

               << "\"\n"

                  "  \""

               << this->LocalGenerator->MaybeRelativeToCurBinDir(stamp)

               << "\"\n";

    }

    fcStream << "  )\n";

  }

  return true;

}

bool cmDependsFortran::LocateModules()

{

  // Collect the set of modules provided and required by all sources.

  using ObjectInfoMap = cmDependsFortranInternals::ObjectInfoMap;

  ObjectInfoMap const& objInfo = this->Internal->ObjectInfo;

  for (auto const& infoI : objInfo) {

    cmFortranSourceInfo const& info = infoI.second;

    // Include this module in the set provided by this target.

    this->Internal->TargetProvides.insert(info.Provides.begin(),

                                          info.Provides.end());

    for (std::string const& r : info.Requires) {

      this->Internal->TargetRequires[r].clear();

    }

  }

  // Short-circuit for simple targets.

  if (this->Internal->TargetRequires.empty()) {

    return true;

  }

  // Match modules provided by this target to those it requires.

  this->MatchLocalModules();

  // Load information about other targets.

  cmMakefile* mf = this->LocalGenerator->GetMakefile();

  cmList infoFiles{ mf->GetDefinition(

    "CMAKE_Fortran_TARGET_LINKED_INFO_FILES") };

  for (auto const& i : infoFiles) {

    std::string targetDir = cmSystemTools::GetFilenamePath(i);

    std::string fname = targetDir + "/fortran.internal";

    cmsys::ifstream fin(fname.c_str());

    if (!fin) {

      cmSystemTools::Error(cmStrCat("-E cmake_depends failed to open ", fname,

                                    " for module information"));

      return false;

    }

    this->MatchRemoteModules(fin, targetDir);

  }

  // TODO: Use `CMAKE_Fortran_TARGET_FORWARD_LINKED_INFO_FILES` to handle cases

  // described in #25425. Note that because Makefiles generators do not

  // implement relaxed object compilation as described in #15555, the issues

  // never actually cause build failures; only incremental build incorrectness.

  return true;

}

void cmDependsFortran::MatchLocalModules()

{

  std::string const& stampDir = this->TargetDirectory;

  std::set<std::string> const& provides = this->Internal->TargetProvides;

  for (std::string const& i : provides) {

    this->ConsiderModule(i, stampDir);

  }

}

void cmDependsFortran::MatchRemoteModules(std::istream& fin,

                                          std::string const& stampDir)

{

  std::string line;

  bool doing_provides = false;

  while (cmSystemTools::GetLineFromStream(fin, line)) {

    // Ignore comments and empty lines.

    if (line.empty() || line[0] == '#' || line[0] == '\r') {

      continue;

    }

    if (line[0] == ' ') {

      if (doing_provides) {

        std::string mod = line;

        if (!cmHasLiteralSuffix(mod, ".mod") &&

            !cmHasLiteralSuffix(mod, ".smod") &&

            !cmHasLiteralSuffix(mod, ".sub")) {

          // Support fortran.internal files left by older versions of CMake.

          // They do not include the ".mod" extension.

          mod += ".mod";

        }

        this->ConsiderModule(mod.substr(1), stampDir);

      }

    } else if (line == "provides") {

      doing_provides = true;

    } else {

      doing_provides = false;

    }

  }

}

void cmDependsFortran::ConsiderModule(std::string const& name,

                                      std::string const& stampDir)

{

  // Locate each required module.

  auto required = this->Internal->TargetRequires.find(name);

  if (required != this->Internal->TargetRequires.end() &&

      required->second.empty()) {

    // The module is provided by a CMake target.  It will have a stamp file.

    std::string stampFile = cmStrCat(stampDir, '/', name, ".stamp");

    required->second = stampFile;

  }

}

bool cmDependsFortran::WriteDependenciesReal(std::string const& obj,

                                             cmFortranSourceInfo const& info,

                                             std::string const& mod_dir,

                                             std::string const& stamp_dir,

                                             std::ostream& makeDepends,

                                             std::ostream& internalDepends,

                                             bool buildingIntrinsics)

{

  // Get the source file for this object.

  std::string const& src = info.Source;

  // Write the include dependencies to the output stream.

  std::string obj_i = this->LocalGenerator->MaybeRelativeToTopBinDir(obj);

  std::string obj_m = cmSystemTools::ConvertToOutputPath(obj_i);

  internalDepends << obj_i << "\n " << src << '\n';

  if (!info.Includes.empty()) {

    auto const& lineContinue = static_cast<cmGlobalUnixMakefileGenerator3*>(

                                 this->LocalGenerator->GetGlobalGenerator())

                                 ->LineContinueDirective;

    bool supportLongLineDepend = static_cast<cmGlobalUnixMakefileGenerator3*>(

                                   this->LocalGenerator->GetGlobalGenerator())

                                   ->SupportsLongLineDependencies();

    if (supportLongLineDepend) {

      makeDepends << obj_m << ':';

    }

    for (std::string const& i : info.Includes) {

      std::string dependee = cmSystemTools::ConvertToOutputPath(

        this->LocalGenerator->MaybeRelativeToTopBinDir(i));

      if (supportLongLineDepend) {

        makeDepends << ' ' << lineContinue << ' ' << dependee;

      } else {

        makeDepends << obj_m << ": " << dependee << '\n';

      }

      internalDepends << ' ' << i << '\n';

    }

    makeDepends << '\n';

  }

  std::set<std::string> req = info.Requires;

  if (buildingIntrinsics) {

    req.insert(info.Intrinsics.begin(), info.Intrinsics.end());

  }

  // Write module requirements to the output stream.

  for (std::string const& i : req) {

    // Require only modules not provided in the same source.

    if (info.Provides.find(i) != info.Provides.cend()) {

      continue;

    }

    // The object file should depend on timestamped files for the

    // modules it uses.

    auto required = this->Internal->TargetRequires.find(i);

    if (required == this->Internal->TargetRequires.end()) {

      abort();

    }

    if (!required->second.empty()) {

      // This module is known.  Depend on its timestamp file.

      std::string stampFile = cmSystemTools::ConvertToOutputPath(

        this->LocalGenerator->MaybeRelativeToTopBinDir(required->second));

      makeDepends << obj_m << ": " << stampFile << '\n';

    } else {

      // This module is not known to CMake.  Try to locate it where

      // the compiler will and depend on that.

      std::string module;

      if (this->FindModule(i, module)) {

        module = cmSystemTools::ConvertToOutputPath(

          this->LocalGenerator->MaybeRelativeToTopBinDir(module));

        makeDepends << obj_m << ": " << module << '\n';

      }

    }

  }

  // If any modules are provided then they must be converted to stamp files.

  if (!info.Provides.empty()) {

    // Create a target to copy the module after the object file

    // changes.

    for (std::string const& i : info.Provides) {

      // Include this module in the set provided by this target.

      this->Internal->TargetProvides.insert(i);

      // Always use lower case for the mod stamp file name.  The

      // cmake_copy_f90_mod will call back to this class, which will

      // try various cases for the real mod file name.

      std::string modFile = cmStrCat(mod_dir, '/', i);

      modFile = this->LocalGenerator->ConvertToOutputFormat(

        this->LocalGenerator->MaybeRelativeToTopBinDir(modFile),

        cmOutputConverter::SHELL);

      std::string stampFile = cmStrCat(stamp_dir, '/', i, ".stamp");

      stampFile = this->LocalGenerator->MaybeRelativeToTopBinDir(stampFile);

      std::string const stampFileForShell =

        this->LocalGenerator->ConvertToOutputFormat(stampFile,

                                                    cmOutputConverter::SHELL);

      std::string const stampFileForMake =

        cmSystemTools::ConvertToOutputPath(stampFile);

      makeDepends << obj_m << ".provides.build"

                  << ": " << stampFileForMake << '\n';

      // Note that when cmake_copy_f90_mod finds that a module file

      // and the corresponding stamp file have no differences, the stamp

      // file is not updated. In such case the stamp file will be always

      // older than its prerequisite and trigger cmake_copy_f90_mod

      // on each new build. This is expected behavior for incremental

      // builds and can not be changed without performing recursive make

      // calls that would considerably slow down the building process.

      makeDepends << stampFileForMake << ": " << obj_m << '\n';

      makeDepends << "\t$(CMAKE_COMMAND) -E cmake_copy_f90_mod " << modFile

                  << ' ' << stampFileForShell;

      cmMakefile* mf = this->LocalGenerator->GetMakefile();

      cmValue cid = mf->GetDefinition("CMAKE_Fortran_COMPILER_ID");

      if (cmNonempty(cid)) {

        makeDepends << ' ' << *cid;

      }

      makeDepends << '\n';

    }

    makeDepends << obj_m << ".provides.build:\n";

    // After copying the modules update the timestamp file.

    makeDepends << "\t$(CMAKE_COMMAND) -E touch " << obj_m

                << ".provides.build\n";

    // Make sure the module timestamp rule is evaluated by the time

    // the target finishes building.

    std::string driver = cmStrCat(this->TargetDirectory, "/build");

    driver = cmSystemTools::ConvertToOutputPath(

      this->LocalGenerator->MaybeRelativeToTopBinDir(driver));

    makeDepends << driver << ": " << obj_m << ".provides.build\n";

  }

  return true;

}

bool cmDependsFortran::FindModule(std::string const& name, std::string& module)

{

  // Construct possible names for the module file.

  std::string mod_upper;

  std::string mod_lower;

  cmFortranModuleAppendUpperLower(name, mod_upper, mod_lower);

  // Search the include path for the module.

  std::string fullName;

  for (std::string const& ip : this->IncludePath) {

    // Try the lower-case name.

    fullName = cmStrCat(ip, '/', mod_lower);

    if (cmSystemTools::FileExists(fullName, true)) {

      module = fullName;

      return true;

    }

    // Try the upper-case name.

    fullName = cmStrCat(ip, '/', mod_upper);

    if (cmSystemTools::FileExists(fullName, true)) {

      module = fullName;

      return true;

    }

  }

  return false;

}

bool cmDependsFortran::CopyModule(std::vector<std::string> const& args)

{

  // Implements

  //

  //   $(CMAKE_COMMAND) -E cmake_copy_f90_mod input.mod output.mod.stamp

  //                                          [compiler-id]

  //

  // Note that the case of the .mod file depends on the compiler.  In

  // the future this copy could also account for the fact that some

  // compilers include a timestamp in the .mod file so it changes even

  // when the interface described in the module does not.

  std::string mod = args[2];

  std::string const& stamp = args[3];

  std::string compilerId;

  if (args.size() >= 5) {

    compilerId = args[4];

  }

  if (!cmHasLiteralSuffix(mod, ".mod") && !cmHasLiteralSuffix(mod, ".smod") &&

      !cmHasLiteralSuffix(mod, ".sub")) {

    // Support depend.make files left by older versions of CMake.

    // They do not include the ".mod" extension.

    mod += ".mod";

  }

  std::string mod_dir = cmSystemTools::GetFilenamePath(mod);

  if (!mod_dir.empty()) {

    mod_dir += "/";

  }

  std::string mod_upper = mod_dir;

  std::string mod_lower = mod_dir;

  cmFortranModuleAppendUpperLower(cmSystemTools::GetFilenameName(mod),

                                  mod_upper, mod_lower);

  if (cmSystemTools::FileExists(mod_upper, true)) {

    if (cmDependsFortran::ModulesDiffer(mod_upper, stamp, compilerId)) {

      if (!cmSystemTools::CopyFileAlways(mod_upper, stamp)) {

        std::cerr << "Error copying Fortran module from \"" << mod_upper

                  << "\" to \"" << stamp << "\".\n";

        return false;

      }

    }

    return true;

  }

  if (cmSystemTools::FileExists(mod_lower, true)) {

    if (cmDependsFortran::ModulesDiffer(mod_lower, stamp, compilerId)) {

      if (!cmSystemTools::CopyFileAlways(mod_lower, stamp)) {

        std::cerr << "Error copying Fortran module from \"" << mod_lower

                  << "\" to \"" << stamp << "\".\n";

        return false;

      }

    }

    return true;

  }

  std::cerr << "Error copying Fortran module \"" << args[2] << "\".  Tried \""

            << mod_upper << "\" and \"" << mod_lower << "\".\n";

  return false;

}

// Helper function to look for a short sequence in a stream.  If this

// is later used for longer sequences it should be re-written using an

// efficient string search algorithm such as Boyer-Moore.

static bool cmFortranStreamContainsSequence(std::istream& ifs, char const* seq,

                                            int len)

{

  assert(len > 0);

  int cur = 0;

  while (cur < len) {

    // Get the next character.

    int token = ifs.get();

    if (!ifs) {

      return false;

    }

    // Check the character.

    if (token == static_cast<int>(seq[cur])) {

      ++cur;

    } else {

      // Assume the sequence has no repeating subsequence.

      cur = 0;

    }

  }

  // The entire sequence was matched.

  return true;

}

// Helper function to compare the remaining content in two streams.

static bool cmFortranStreamsDiffer(std::istream& ifs1, std::istream& ifs2)

{

  // Compare the remaining content.

  for (;;) {

    int ifs1_c = ifs1.get();

    int ifs2_c = ifs2.get();

    if (!ifs1 && !ifs2) {

      // We have reached the end of both streams simultaneously.

      // The streams are identical.

      return false;

    }

    if (!ifs1 || !ifs2 || ifs1_c != ifs2_c) {

      // We have reached the end of one stream before the other or

      // found differing content.  The streams are different.

      break;

    }

  }

  return true;

}

bool cmDependsFortran::ModulesDiffer(std::string const& modFile,

                                     std::string const& stampFile,

                                     std::string const& compilerId)

{

  /*

  gnu >= 4.9:

    A mod file is an ascii file compressed with gzip.

    Compiling twice produces identical modules.

  gnu < 4.9:

    A mod file is an ascii file.

    <bar.mod>

    FORTRAN module created from /path/to/foo.f90 on Sun Dec 30 22:47:58 2007

    If you edit this, you'll get what you deserve.

    ...

    </bar.mod>

    As you can see the first line contains the date.

  intel:

    A mod file is a binary file.

    However, looking into both generated bar.mod files with a hex editor

    shows that they differ only before a sequence linefeed-zero (0x0A 0x00)

    which is located some bytes in front of the absolute path to the source

    file.

  sun:

    A mod file is a binary file.  Compiling twice produces identical modules.

  others:

    TODO ...

  */

  /* Compilers which do _not_ produce different mod content when the same

   * source is compiled twice

   *   -SunPro

   */

  if (compilerId == "SunPro") {

    return cmSystemTools::FilesDiffer(modFile, stampFile);

  }

#if defined(_WIN32) || defined(__CYGWIN__)

  cmsys::ifstream finModFile(modFile.c_str(), std::ios::in | std::ios::binary);

  cmsys::ifstream finStampFile(stampFile.c_str(),

                               std::ios::in | std::ios::binary);

#else

  cmsys::ifstream finModFile(modFile.c_str());

  cmsys::ifstream finStampFile(stampFile.c_str());

#endif

  if (!finModFile || !finStampFile) {

    // At least one of the files does not exist.  The modules differ.

    return true;

  }

  /* Compilers which _do_ produce different mod content when the same

   * source is compiled twice

   *   -GNU

   *   -Intel

   *

   * Eat the stream content until all recompile only related changes

   * are left behind.

   */

  if (compilerId == "GNU") {

    // GNU Fortran 4.9 and later compress .mod files with gzip

    // but also do not include a date so we can fall through to

    // compare them without skipping any prefix.

    unsigned char hdr[2];

    bool okay = !finModFile.read(reinterpret_cast<char*>(hdr), 2).fail();

    finModFile.seekg(0);

    if (!okay || hdr[0] != 0x1f || hdr[1] != 0x8b) {

      char const seq[1] = { '\n' };

      int const seqlen = 1;

      if (!cmFortranStreamContainsSequence(finModFile, seq, seqlen)) {

        // The module is of unexpected format.  Assume it is different.

        std::cerr << compilerId << " fortran module " << modFile

                  << " has unexpected format." << std::endl;

        return true;

      }

      if (!cmFortranStreamContainsSequence(finStampFile, seq, seqlen)) {

        // The stamp must differ if the sequence is not contained.

        return true;

      }

    }

  } else if (compilerId == "Intel" || compilerId == "IntelLLVM") {

    char const seq[2] = { '\n', '\0' };

    int const seqlen = 2;

    // Skip the leading byte which appears to be a version number.

    // We do not need to check for an error because the sequence search

    // below will fail in that case.

    finModFile.get();

    finStampFile.get();

    if (!cmFortranStreamContainsSequence(finModFile, seq, seqlen)) {

      // The module is of unexpected format.  Assume it is different.

      std::cerr << compilerId << " fortran module " << modFile

                << " has unexpected format." << std::endl;

      return true;

    }

    if (!cmFortranStreamContainsSequence(finStampFile, seq, seqlen)) {

      // The stamp must differ if the sequence is not contained.

      return true;

    }

  }

  // Compare the remaining content.  If no compiler id matched above,

  // including the case none was given, this will compare the whole

  // content.

  return cmFortranStreamsDiffer(finModFile, finStampFile);

}