CMake/Source/cmcmd.cxx

/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   file Copyright.txt or https://cmake.org/licensing for details.  */
#include "cmcmd.h"

#include "cmAlgorithms.h"
#include "cmGlobalGenerator.h"
#include "cmLocalGenerator.h"
#include "cmMakefile.h"
#include "cmQtAutoGenerators.h"
#include "cmStateDirectory.h"
#include "cmStateSnapshot.h"
#include "cmSystemTools.h"
#include "cmUtils.hxx"
#include "cmVersion.h"
#include "cm_auto_ptr.hxx"
#include "cmake.h"

#if defined(HAVE_SERVER_MODE) && HAVE_SERVER_MODE
#include "cmServer.h"
#include "cmServerConnection.h"
#endif

#if defined(CMAKE_BUILD_WITH_CMAKE)
#include "cmDependsFortran.h" // For -E cmake_copy_f90_mod callback.
#endif

#if defined(CMAKE_BUILD_WITH_CMAKE) && defined(_WIN32)
#include "bindexplib.h"
#endif

#if defined(CMAKE_BUILD_WITH_CMAKE) && defined(_WIN32) && !defined(__CYGWIN__)
#include "cmVisualStudioWCEPlatformParser.h"
#endif

#include "cmConfigure.h"
#include "cmsys/Directory.hxx"
#include "cmsys/FStream.hxx"
#include "cmsys/Process.h"
#include "cmsys/Terminal.h"
#include <algorithm>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int cmcmd_cmake_ninja_depends(std::vector<std::string>::const_iterator argBeg,
                              std::vector<std::string>::const_iterator argEnd);
int cmcmd_cmake_ninja_dyndep(std::vector<std::string>::const_iterator argBeg,
                             std::vector<std::string>::const_iterator argEnd);

void CMakeCommandUsage(const char* program)
{
  std::ostringstream errorStream;

#ifdef CMAKE_BUILD_WITH_CMAKE
  /* clang-format off */
  errorStream
    << "cmake version " << cmVersion::GetCMakeVersion() << "\n";
/* clang-format on */
#else
  /* clang-format off */
  errorStream
    << "cmake bootstrap\n";
/* clang-format on */
#endif
  // If you add new commands, change here,
  // and in cmakemain.cxx in the options table
  /* clang-format off */
  errorStream
    << "Usage: " << program << " -E <command> [arguments...]\n"
    << "Available commands: \n"
    << "  capabilities              - Report capabilities built into cmake "
       "in JSON format\n"
    << "  chdir dir cmd [args...]   - run command in a given directory\n"
    << "  compare_files file1 file2 - check if file1 is same as file2\n"
    << "  copy <file>... destination  - copy files to destination "
       "(either file or directory)\n"
    << "  copy_directory <dir>... destination   - copy content of <dir>... "
       "directories to 'destination' directory\n"
    << "  copy_if_different <file>... destination  - copy files if it has "
       "changed\n"
    << "  echo [<string>...]        - displays arguments as text\n"
    << "  echo_append [<string>...] - displays arguments as text but no new "
       "line\n"
    << "  env [--unset=NAME]... [NAME=VALUE]... COMMAND [ARG]...\n"
    << "                            - run command in a modified environment\n"
    << "  environment               - display the current environment\n"
    << "  make_directory <dir>...   - create parent and <dir> directories\n"
    << "  md5sum <file>...          - create MD5 checksum of files\n"
    << "  remove [-f] <file>...     - remove the file(s), use -f to force "
       "it\n"
    << "  remove_directory dir      - remove a directory and its contents\n"
    << "  rename oldname newname    - rename a file or directory "
       "(on one volume)\n"
    << "  server                    - start cmake in server mode\n"
    << "  sleep <number>...         - sleep for given number of seconds\n"
    << "  tar [cxt][vf][zjJ] file.tar [file/dir1 file/dir2 ...]\n"
    << "                            - create or extract a tar or zip archive\n"
    << "  time command [args...]    - run command and return elapsed time\n"
    << "  touch file                - touch a file.\n"
    << "  touch_nocreate file       - touch a file but do not create it.\n"
#if defined(_WIN32) && !defined(__CYGWIN__)
    << "Available on Windows only:\n"
    << "  delete_regv key           - delete registry value\n"
    << "  env_vs8_wince sdkname     - displays a batch file which sets the "
       "environment for the provided Windows CE SDK installed in VS2005\n"
    << "  env_vs9_wince sdkname     - displays a batch file which sets the "
       "environment for the provided Windows CE SDK installed in VS2008\n"
    << "  write_regv key value      - write registry value\n"
#else
    << "Available on UNIX only:\n"
    << "  create_symlink old new    - create a symbolic link new -> old\n"
#endif
    ;
  /* clang-format on */

  cmSystemTools::Error(errorStream.str().c_str());
}

static bool cmTarFilesFrom(std::string const& file,
                           std::vector<std::string>& files)
{
  if (cmSystemTools::FileIsDirectory(file)) {
    std::ostringstream e;
    e << "-E tar --files-from= file '" << file << "' is a directory";
    cmSystemTools::Error(e.str().c_str());
    return false;
  }
  cmsys::ifstream fin(file.c_str());
  if (!fin) {
    std::ostringstream e;
    e << "-E tar --files-from= file '" << file << "' not found";
    cmSystemTools::Error(e.str().c_str());
    return false;
  }
  std::string line;
  while (cmSystemTools::GetLineFromStream(fin, line)) {
    if (line.empty()) {
      continue;
    }
    if (cmHasLiteralPrefix(line, "--add-file=")) {
      files.push_back(line.substr(11));
    } else if (cmHasLiteralPrefix(line, "-")) {
      std::ostringstream e;
      e << "-E tar --files-from='" << file << "' file invalid line:\n"
        << line << "\n";
      cmSystemTools::Error(e.str().c_str());
      return false;
    } else {
      files.push_back(line);
    }
  }
  return true;
}

int cmcmd::ExecuteCMakeCommand(std::vector<std::string>& args)
{
  // IF YOU ADD A NEW COMMAND, DOCUMENT IT ABOVE and in cmakemain.cxx
  if (args.size() > 1) {
    // Copy file
    if (args[1] == "copy" && args.size() > 3) {
      // If multiple source files specified,
      // then destination must be directory
      if ((args.size() > 4) &&
          (!cmSystemTools::FileIsDirectory(args[args.size() - 1]))) {
        std::cerr << "Error: Target (for copy command) \""
                  << args[args.size() - 1] << "\" is not a directory.\n";
        return 1;
      }
      // If error occurs we want to continue copying next files.
      bool return_value = false;
      for (std::string::size_type cc = 2; cc < args.size() - 1; cc++) {
        if (!cmSystemTools::cmCopyFile(args[cc].c_str(),
                                       args[args.size() - 1].c_str())) {
          std::cerr << "Error copying file \"" << args[cc] << "\" to \""
                    << args[args.size() - 1] << "\".\n";
          return_value = true;
        }
      }
      return return_value;
    }

    // Copy file if different.
    if (args[1] == "copy_if_different" && args.size() > 3) {
      // If multiple source files specified,
      // then destination must be directory
      if ((args.size() > 4) &&
          (!cmSystemTools::FileIsDirectory(args[args.size() - 1]))) {
        std::cerr << "Error: Target (for copy_if_different command) \""
                  << args[args.size() - 1] << "\" is not a directory.\n";
        return 1;
      }
      // If error occurs we want to continue copying next files.
      bool return_value = false;
      for (std::string::size_type cc = 2; cc < args.size() - 1; cc++) {
        if (!cmSystemTools::CopyFileIfDifferent(
              args[cc].c_str(), args[args.size() - 1].c_str())) {
          std::cerr << "Error copying file (if different) from \"" << args[cc]
                    << "\" to \"" << args[args.size() - 1] << "\".\n";
          return_value = true;
        }
      }
      return return_value;
    }

    // Copy directory content
    if (args[1] == "copy_directory" && args.size() > 3) {
      // If error occurs we want to continue copying next files.
      bool return_value = false;
      for (std::string::size_type cc = 2; cc < args.size() - 1; cc++) {
        if (!cmSystemTools::CopyADirectory(args[cc], args[args.size() - 1])) {
          std::cerr << "Error copying directory from \"" << args[cc]
                    << "\" to \"" << args[args.size() - 1] << "\".\n";
          return_value = true;
        }
      }
      return return_value;
    }

    // Rename a file or directory
    if (args[1] == "rename" && args.size() == 4) {
      if (!cmSystemTools::RenameFile(args[2].c_str(), args[3].c_str())) {
        std::string e = cmSystemTools::GetLastSystemError();
        std::cerr << "Error renaming from \"" << args[2] << "\" to \""
                  << args[3] << "\": " << e << "\n";
        return 1;
      }
      return 0;
    }

    // Compare files
    if (args[1] == "compare_files" && args.size() == 4) {
      if (cmSystemTools::FilesDiffer(args[2], args[3])) {
        std::cerr << "Files \"" << args[2] << "\" to \"" << args[3]
                  << "\" are different.\n";
        return 1;
      }
      return 0;
    }

#if defined(_WIN32) && defined(CMAKE_BUILD_WITH_CMAKE)
    else if (args[1] == "__create_def") {
      if (args.size() < 4) {
        std::cerr
          << "__create_def Usage: -E __create_def outfile.def objlistfile\n";
        return 1;
      }
      FILE* fout = cmsys::SystemTools::Fopen(args[2].c_str(), "w+");
      if (!fout) {
        std::cerr << "could not open output .def file: " << args[2].c_str()
                  << "\n";
        return 1;
      }
      cmsys::ifstream fin(args[3].c_str(), std::ios::in | std::ios::binary);
      if (!fin) {
        std::cerr << "could not open object list file: " << args[3].c_str()
                  << "\n";
        return 1;
      }
      std::string file;
      bindexplib deffile;
      while (cmSystemTools::GetLineFromStream(fin, file)) {
        std::string const& ext = cmSystemTools::GetFilenameLastExtension(file);
        if (cmSystemTools::LowerCase(ext) == ".def") {
          if (!deffile.AddDefinitionFile(file.c_str())) {
            return 1;
          }
        } else {
          if (!deffile.AddObjectFile(file.c_str())) {
            return 1;
          }
        }
      }
      deffile.WriteFile(fout);
      fclose(fout);
      return 0;
    }
#endif
    // run include what you use command and then run the compile
    // command. This is an internal undocumented option and should
    // only be used by CMake itself when running iwyu.
    if (args[1] == "__run_iwyu") {
      if (args.size() < 3) {
        std::cerr << "__run_iwyu Usage: -E __run_iwyu [--iwyu=/path/iwyu]"
                     " [--cpplint=/path/cpplint] [--tidy=/path/tidy]"
                     " -- compile command\n";
        return 1;
      }
      bool doing_options = true;
      std::vector<std::string> orig_cmd;
      std::string iwyu;
      std::string tidy;
      std::string sourceFile;
      std::string lwyu;
      std::string cpplint;
      for (std::string::size_type cc = 2; cc < args.size(); cc++) {
        std::string const& arg = args[cc];
        if (arg == "--") {
          doing_options = false;
        } else if (doing_options && cmHasLiteralPrefix(arg, "--iwyu=")) {
          iwyu = arg.substr(7);
        } else if (doing_options && cmHasLiteralPrefix(arg, "--tidy=")) {
          tidy = arg.substr(7);
        } else if (doing_options && cmHasLiteralPrefix(arg, "--source=")) {
          sourceFile = arg.substr(9);
        } else if (doing_options && cmHasLiteralPrefix(arg, "--lwyu=")) {
          lwyu = arg.substr(7);
        } else if (doing_options && cmHasLiteralPrefix(arg, "--cpplint=")) {
          cpplint = arg.substr(10);
        } else if (doing_options) {
          std::cerr << "__run_iwyu given unknown argument: " << arg << "\n";
          return 1;
        } else {
          orig_cmd.push_back(arg);
        }
      }
      if (tidy.empty() && iwyu.empty() && lwyu.empty() && cpplint.empty()) {
        std::cerr << "__run_iwyu missing --cpplint=, --iwyu=, --lwyu=, and/or"
                     " --tidy=\n";
        return 1;
      }
      if ((!cpplint.empty() || !tidy.empty()) && sourceFile.empty()) {
        std::cerr << "__run_iwyu --cpplint= and/or __run_iwyu --tidy="
                     " require --source=\n";
        return 1;
      }
      if (orig_cmd.empty() && lwyu.empty()) {
        std::cerr << "__run_iwyu missing compile command after --\n";
        return 1;
      }

      int ret = 0;

      if (!iwyu.empty()) {
        // Construct the iwyu command line by taking what was given
        // and adding all the arguments we give to the compiler.
        std::vector<std::string> iwyu_cmd;
        cmSystemTools::ExpandListArgument(iwyu, iwyu_cmd, true);
        iwyu_cmd.insert(iwyu_cmd.end(), orig_cmd.begin() + 1, orig_cmd.end());

        // Run the iwyu command line.  Capture its stderr and hide its stdout.
        // Ignore its return code because the tool always returns non-zero.
        std::string stdErr;
        if (!cmSystemTools::RunSingleCommand(iwyu_cmd, CM_NULLPTR, &stdErr,
                                             &ret, CM_NULLPTR,
                                             cmSystemTools::OUTPUT_NONE)) {
          std::cerr << "Error running '" << iwyu_cmd[0] << "': " << stdErr
                    << "\n";
          return 1;
        }

        // Warn if iwyu reported anything.
        if (stdErr.find("should remove these lines:") != stdErr.npos ||
            stdErr.find("should add these lines:") != stdErr.npos) {
          std::cerr << "Warning: include-what-you-use reported diagnostics:\n"
                    << stdErr << "\n";
        }
      }

      if (!tidy.empty()) {
        // Construct the clang-tidy command line by taking what was given
        // and adding our compiler command line.  The clang-tidy tool will
        // automatically skip over the compiler itself and extract the
        // options.
        std::vector<std::string> tidy_cmd;
        cmSystemTools::ExpandListArgument(tidy, tidy_cmd, true);
        tidy_cmd.push_back(sourceFile);
        tidy_cmd.push_back("--");
        tidy_cmd.insert(tidy_cmd.end(), orig_cmd.begin(), orig_cmd.end());

        // Run the tidy command line.  Capture its stdout and hide its stderr.
        std::string stdOut;
        std::string stdErr;
        if (!cmSystemTools::RunSingleCommand(tidy_cmd, &stdOut, &stdErr, &ret,
                                             CM_NULLPTR,
                                             cmSystemTools::OUTPUT_NONE)) {
          std::cerr << "Error running '" << tidy_cmd[0] << "': " << stdErr
                    << "\n";
          return 1;
        }
        // Output the stdout from clang-tidy to stderr
        std::cerr << stdOut;
        // If clang-tidy exited with an error do the same.
        if (ret != 0) {
          std::cerr << stdErr;
          return ret;
        }
      }
      if (!lwyu.empty()) {
        // Construct the ldd -r -u (link what you use lwyu) command line
        // ldd -u -r lwuy target
        std::vector<std::string> lwyu_cmd;
        lwyu_cmd.push_back("ldd");
        lwyu_cmd.push_back("-u");
        lwyu_cmd.push_back("-r");
        lwyu_cmd.push_back(lwyu);

        // Run the ldd -u -r command line.
        // Capture its stdout and hide its stderr.
        // Ignore its return code because the tool always returns non-zero
        // if there are any warnings, but we just want to warn.
        std::string stdOut;
        std::string stdErr;
        if (!cmSystemTools::RunSingleCommand(lwyu_cmd, &stdOut, &stdErr, &ret,
                                             CM_NULLPTR,
                                             cmSystemTools::OUTPUT_NONE)) {
          std::cerr << "Error running '" << lwyu_cmd[0] << "': " << stdErr
                    << "\n";
          return 1;
        }

        // Output the stdout from ldd -r -u to stderr
        // Warn if lwyu reported anything.
        if (stdOut.find("Unused direct dependencies:") != stdOut.npos) {
          std::cerr << "Warning: " << stdOut;
        }
      }

      if (!cpplint.empty()) {
        // Construct the cpplint command line.
        std::vector<std::string> cpplint_cmd;
        cmSystemTools::ExpandListArgument(cpplint, cpplint_cmd, true);
        cpplint_cmd.push_back(sourceFile);

        // Run the cpplint command line.  Capture its output.
        std::string stdOut;
        if (!cmSystemTools::RunSingleCommand(cpplint_cmd, &stdOut, &stdOut,
                                             &ret, CM_NULLPTR,
                                             cmSystemTools::OUTPUT_NONE)) {
          std::cerr << "Error running '" << cpplint_cmd[0] << "': " << stdOut
                    << "\n";
          return 1;
        }

        // Output the output from cpplint to stderr
        std::cerr << stdOut;

        // If cpplint exited with an error do the same.
        if (ret != 0) {
          return ret;
        }
      }

      ret = 0;
      // Now run the real compiler command and return its result value.
      if (lwyu.empty() &&
          !cmSystemTools::RunSingleCommand(
            orig_cmd, CM_NULLPTR, CM_NULLPTR, &ret, CM_NULLPTR,
            cmSystemTools::OUTPUT_PASSTHROUGH)) {
        std::cerr << "Error running '" << orig_cmd[0] << "'\n";
        return 1;
      }
      return ret;
    }

    // Echo string
    if (args[1] == "echo") {
      std::cout << cmJoin(cmMakeRange(args).advance(2), " ") << std::endl;
      return 0;
    }

    // Echo string no new line
    if (args[1] == "echo_append") {
      std::cout << cmJoin(cmMakeRange(args).advance(2), " ");
      return 0;
    }

    if (args[1] == "env") {
      std::vector<std::string>::const_iterator ai = args.begin() + 2;
      std::vector<std::string>::const_iterator ae = args.end();
      for (; ai != ae; ++ai) {
        std::string const& a = *ai;
        if (cmHasLiteralPrefix(a, "--unset=")) {
          // Unset environment variable.
          cmSystemTools::UnPutEnv(a.c_str() + 8);
        } else if (!a.empty() && a[0] == '-') {
          // Environment variable and command names cannot start in '-',
          // so this must be an unknown option.
          std::cerr << "cmake -E env: unknown option '" << a << "'"
                    << std::endl;
          return 1;
        } else if (a.find('=') != a.npos) {
          // Set environment variable.
          cmSystemTools::PutEnv(a);
        } else {
          // This is the beginning of the command.
          break;
        }
      }

      if (ai == ae) {
        std::cerr << "cmake -E env: no command given" << std::endl;
        return 1;
      }

      // Execute command from remaining arguments.
      std::vector<std::string> cmd(ai, ae);
      int retval;
      if (cmSystemTools::RunSingleCommand(cmd, CM_NULLPTR, CM_NULLPTR, &retval,
                                          CM_NULLPTR,
                                          cmSystemTools::OUTPUT_PASSTHROUGH)) {
        return retval;
      }
      return 1;
    }

#if defined(CMAKE_BUILD_WITH_CMAKE)
    if (args[1] == "environment") {
      std::vector<std::string> env = cmSystemTools::GetEnvironmentVariables();
      std::vector<std::string>::iterator it;
      for (it = env.begin(); it != env.end(); ++it) {
        std::cout << *it << std::endl;
      }
      return 0;
    }
#endif

    if (args[1] == "make_directory" && args.size() > 2) {
      // If error occurs we want to continue copying next files.
      bool return_value = false;
      for (std::string::size_type cc = 2; cc < args.size(); cc++) {
        if (!cmSystemTools::MakeDirectory(args[cc].c_str())) {
          std::cerr << "Error creating directory \"" << args[cc] << "\".\n";
          return_value = true;
        }
      }
      return return_value;
    }

    if (args[1] == "remove_directory" && args.size() == 3) {
      if (cmSystemTools::FileIsDirectory(args[2]) &&
          !cmSystemTools::RemoveADirectory(args[2])) {
        std::cerr << "Error removing directory \"" << args[2] << "\".\n";
        return 1;
      }
      return 0;
    }

    // Remove file
    if (args[1] == "remove" && args.size() > 2) {
      bool force = false;
      for (std::string::size_type cc = 2; cc < args.size(); cc++) {
        if (args[cc] == "\\-f" || args[cc] == "-f") {
          force = true;
        } else {
          // Complain if the file could not be removed, still exists,
          // and the -f option was not given.
          if (!cmSystemTools::RemoveFile(args[cc]) && !force &&
              cmSystemTools::FileExists(args[cc].c_str())) {
            return 1;
          }
        }
      }
      return 0;
    }

    // Touch file
    if (args[1] == "touch" && args.size() > 2) {
      for (std::string::size_type cc = 2; cc < args.size(); cc++) {
        if (!cmSystemTools::Touch(args[cc], true)) {
          return 1;
        }
      }
      return 0;
    }

    // Touch file
    if (args[1] == "touch_nocreate" && args.size() > 2) {
      for (std::string::size_type cc = 2; cc < args.size(); cc++) {
        // Complain if the file could not be removed, still exists,
        // and the -f option was not given.
        if (!cmSystemTools::Touch(args[cc], false)) {
          return 1;
        }
      }
      return 0;
    }

    // capabilities
    if (args[1] == "capabilities") {
      if (args.size() > 2) {
        std::cerr << "-E capabilities accepts no additional arguments\n";
        return 1;
      }
      cmake cm;
#if defined(HAVE_SERVER_MODE) && HAVE_SERVER_MODE
      std::cout << cm.ReportCapabilities(true);
#else
      std::cout << cm.ReportCapabilities(false);
#endif
      return 0;
    }

    // Sleep command
    if (args[1] == "sleep" && args.size() > 2) {
      double total = 0;
      for (size_t i = 2; i < args.size(); ++i) {
        double num = 0.0;
        char unit;
        char extra;
        int n = sscanf(args[i].c_str(), "%lg%c%c", &num, &unit, &extra);
        if ((n == 1 || (n == 2 && unit == 's')) && num >= 0) {
          total += num;
        } else {
          std::cerr << "Unknown sleep time format \"" << args[i] << "\".\n";
          return 1;
        }
      }
      if (total > 0) {
        cmSystemTools::Delay(static_cast<unsigned int>(total * 1000));
      }
      return 0;
    }

    // Clock command
    if (args[1] == "time" && args.size() > 2) {
      std::vector<std::string> command(args.begin() + 2, args.end());

      clock_t clock_start, clock_finish;
      time_t time_start, time_finish;

      time(&time_start);
      clock_start = clock();
      int ret = 0;
      cmSystemTools::RunSingleCommand(command, CM_NULLPTR, CM_NULLPTR, &ret);

      clock_finish = clock();
      time(&time_finish);

      double clocks_per_sec = static_cast<double>(CLOCKS_PER_SEC);
      std::cout << "Elapsed time: "
                << static_cast<long>(time_finish - time_start) << " s. (time)"
                << ", "
                << static_cast<double>(clock_finish - clock_start) /
          clocks_per_sec
                << " s. (clock)"
                << "\n";
      return ret;
    }

    // Command to calculate the md5sum of a file
    if (args[1] == "md5sum" && args.size() >= 3) {
      char md5out[32];
      int retval = 0;
      for (std::string::size_type cc = 2; cc < args.size(); cc++) {
        const char* filename = args[cc].c_str();
        // Cannot compute md5sum of a directory
        if (cmSystemTools::FileIsDirectory(filename)) {
          std::cerr << "Error: " << filename << " is a directory" << std::endl;
          retval++;
        } else if (!cmSystemTools::ComputeFileMD5(filename, md5out)) {
          // To mimic md5sum behavior in a shell:
          std::cerr << filename << ": No such file or directory" << std::endl;
          retval++;
        } else {
          std::cout << std::string(md5out, 32) << "  " << filename
                    << std::endl;
        }
      }
      return retval;
    }

    // Command to change directory and run a program.
    if (args[1] == "chdir" && args.size() >= 4) {
      std::string directory = args[2];
      if (!cmSystemTools::FileExists(directory.c_str())) {
        cmSystemTools::Error("Directory does not exist for chdir command: ",
                             args[2].c_str());
        return 1;
      }

      std::string command =
        cmWrap('"', cmMakeRange(args).advance(3), '"', " ");
      int retval = 0;
      int timeout = 0;
      if (cmSystemTools::RunSingleCommand(
            command.c_str(), CM_NULLPTR, CM_NULLPTR, &retval,
            directory.c_str(), cmSystemTools::OUTPUT_PASSTHROUGH, timeout)) {
        return retval;
      }

      return 1;
    }

    // Command to start progress for a build
    if (args[1] == "cmake_progress_start" && args.size() == 4) {
      // basically remove the directory
      std::string dirName = args[2];
      dirName += "/Progress";
      cmSystemTools::RemoveADirectory(dirName);

      // is the last argument a filename that exists?
      FILE* countFile = cmsys::SystemTools::Fopen(args[3], "r");
      int count;
      if (countFile) {
        if (1 != fscanf(countFile, "%i", &count)) {
          cmSystemTools::Message("Could not read from count file.");
        }
        fclose(countFile);
      } else {
        count = atoi(args[3].c_str());
      }
      if (count) {
        cmSystemTools::MakeDirectory(dirName.c_str());
        // write the count into the directory
        std::string fName = dirName;
        fName += "/count.txt";
        FILE* progFile = cmsys::SystemTools::Fopen(fName, "w");
        if (progFile) {
          fprintf(progFile, "%i\n", count);
          fclose(progFile);
        }
      }
      return 0;
    }

    // Command to report progress for a build
    if (args[1] == "cmake_progress_report" && args.size() >= 3) {
      // This has been superseded by cmake_echo_color --progress-*
      // options.  We leave it here to avoid errors if somehow this
      // is invoked by an existing makefile without regenerating.
      return 0;
    }

    // Command to create a symbolic link.  Fails on platforms not
    // supporting them.
    if (args[1] == "create_symlink" && args.size() == 4) {
      const char* destinationFileName = args[3].c_str();
      if ((cmSystemTools::FileExists(destinationFileName) ||
           cmSystemTools::FileIsSymlink(destinationFileName)) &&
          !cmSystemTools::RemoveFile(destinationFileName)) {
        std::string emsg = cmSystemTools::GetLastSystemError();
        std::cerr << "failed to create symbolic link '" << destinationFileName
                  << "' because existing path cannot be removed: " << emsg
                  << "\n";
        return 1;
      }
      if (!cmSystemTools::CreateSymlink(args[2], args[3])) {
        std::string emsg = cmSystemTools::GetLastSystemError();
        std::cerr << "failed to create symbolic link '" << destinationFileName
                  << "': " << emsg << "\n";
        return 1;
      }
      return 0;
    }

    // Internal CMake shared library support.
    if (args[1] == "cmake_symlink_library" && args.size() == 5) {
      return cmcmd::SymlinkLibrary(args);
    }

    // Internal CMake versioned executable support.
    if (args[1] == "cmake_symlink_executable" && args.size() == 4) {
      return cmcmd::SymlinkExecutable(args);
    }

    // Internal CMake dependency scanning support.
    if (args[1] == "cmake_depends" && args.size() >= 6) {
      const bool verbose = isCMakeVerbose();

      // Create a cmake object instance to process dependencies.
      cmake cm;
      std::string gen;
      std::string homeDir;
      std::string startDir;
      std::string homeOutDir;
      std::string startOutDir;
      std::string depInfo;
      bool color = false;
      if (args.size() >= 8) {
        // Full signature:
        //
        //   -E cmake_depends <generator>
        //                    <home-src-dir> <start-src-dir>
        //                    <home-out-dir> <start-out-dir>
        //                    <dep-info> [--color=$(COLOR)]
        //
        // All paths are provided.
        gen = args[2];
        homeDir = args[3];
        startDir = args[4];
        homeOutDir = args[5];
        startOutDir = args[6];
        depInfo = args[7];
        if (args.size() >= 9 && args[8].length() >= 8 &&
            args[8].substr(0, 8) == "--color=") {
          // Enable or disable color based on the switch value.
          color = (args[8].size() == 8 ||
                   cmSystemTools::IsOn(args[8].substr(8).c_str()));
        }
      } else {
        // Support older signature for existing makefiles:
        //
        //   -E cmake_depends <generator>
        //                    <home-out-dir> <start-out-dir>
        //                    <dep-info>
        //
        // Just pretend the source directories are the same as the
        // binary directories so at least scanning will work.
        gen = args[2];
        homeDir = args[3];
        startDir = args[4];
        homeOutDir = args[3];
        startOutDir = args[3];
        depInfo = args[5];
      }

      // Create a local generator configured for the directory in
      // which dependencies will be scanned.
      homeDir = cmSystemTools::CollapseFullPath(homeDir);
      startDir = cmSystemTools::CollapseFullPath(startDir);
      homeOutDir = cmSystemTools::CollapseFullPath(homeOutDir);
      startOutDir = cmSystemTools::CollapseFullPath(startOutDir);
      cm.SetHomeDirectory(homeDir);
      cm.SetHomeOutputDirectory(homeOutDir);
      cm.GetCurrentSnapshot().SetDefaultDefinitions();
      if (cmGlobalGenerator* ggd = cm.CreateGlobalGenerator(gen)) {
        cm.SetGlobalGenerator(ggd);
        cmStateSnapshot snapshot = cm.GetCurrentSnapshot();
        snapshot.GetDirectory().SetCurrentBinary(startOutDir);
        snapshot.GetDirectory().SetCurrentSource(startDir);
        CM_AUTO_PTR<cmMakefile> mf(new cmMakefile(ggd, snapshot));
        CM_AUTO_PTR<cmLocalGenerator> lgd(ggd->CreateLocalGenerator(mf.get()));

        // Actually scan dependencies.
        return lgd->UpdateDependencies(depInfo.c_str(), verbose, color) ? 0
                                                                        : 2;
      }
      return 1;
    }

    // Internal CMake link script support.
    if (args[1] == "cmake_link_script" && args.size() >= 3) {
      return cmcmd::ExecuteLinkScript(args);
    }

#ifdef CMAKE_BUILD_WITH_CMAKE
    // Internal CMake ninja dependency scanning support.
    if (args[1] == "cmake_ninja_depends") {
      return cmcmd_cmake_ninja_depends(args.begin() + 2, args.end());
    }

    // Internal CMake ninja dyndep support.
    if (args[1] == "cmake_ninja_dyndep") {
      return cmcmd_cmake_ninja_dyndep(args.begin() + 2, args.end());
    }
#endif

    // Internal CMake unimplemented feature notification.
    if (args[1] == "cmake_unimplemented_variable") {
      std::cerr << "Feature not implemented for this platform.";
      if (args.size() == 3) {
        std::cerr << "  Variable " << args[2] << " is not set.";
      }
      std::cerr << std::endl;
      return 1;
    }

    if (args[1] == "vs_link_exe") {
      return cmcmd::VisualStudioLink(args, 1);
    }

    if (args[1] == "vs_link_dll") {
      return cmcmd::VisualStudioLink(args, 2);
    }

    // Internal CMake color makefile support.
    if (args[1] == "cmake_echo_color") {
      return cmcmd::ExecuteEchoColor(args);
    }

#ifdef CMAKE_BUILD_WITH_CMAKE
    if (args[1] == "cmake_autogen" && args.size() >= 4) {
      cmQtAutoGenerators autogen;
      std::string const& config = args[3];
      bool autogenSuccess = autogen.Run(args[2], config);
      return autogenSuccess ? 0 : 1;
    }
#endif

    // Tar files
    if (args[1] == "tar" && args.size() > 3) {
      const char* knownFormats[] = { "7zip", "gnutar", "pax", "paxr", "zip" };

      std::string flags = args[2];
      std::string outFile = args[3];
      std::vector<std::string> files;
      std::string mtime;
      std::string format;
      bool doing_options = true;
      for (std::string::size_type cc = 4; cc < args.size(); cc++) {
        std::string const& arg = args[cc];
        if (doing_options && cmHasLiteralPrefix(arg, "--")) {
          if (arg == "--") {
            doing_options = false;
          } else if (cmHasLiteralPrefix(arg, "--mtime=")) {
            mtime = arg.substr(8);
          } else if (cmHasLiteralPrefix(arg, "--files-from=")) {
            std::string const& files_from = arg.substr(13);
            if (!cmTarFilesFrom(files_from, files)) {
              return 1;
            }
          } else if (cmHasLiteralPrefix(arg, "--format=")) {
            format = arg.substr(9);
            bool isKnown =
              std::find(cmArrayBegin(knownFormats), cmArrayEnd(knownFormats),
                        format) != cmArrayEnd(knownFormats);

            if (!isKnown) {
              cmSystemTools::Error("Unknown -E tar --format= argument: ",
                                   format.c_str());
              return 1;
            }
          } else {
            cmSystemTools::Error("Unknown option to -E tar: ", arg.c_str());
            return 1;
          }
        } else {
          files.push_back(arg);
        }
      }
      cmSystemTools::cmTarCompression compress =
        cmSystemTools::TarCompressNone;
      bool verbose = false;
      int nCompress = 0;
      if (flags.find_first_of('j') != flags.npos) {
        compress = cmSystemTools::TarCompressBZip2;
        ++nCompress;
      }
      if (flags.find_first_of('J') != flags.npos) {
        compress = cmSystemTools::TarCompressXZ;
        ++nCompress;
      }
      if (flags.find_first_of('z') != flags.npos) {
        compress = cmSystemTools::TarCompressGZip;
        ++nCompress;
      }
      if ((format == "7zip" || format == "zip") && nCompress > 0) {
        cmSystemTools::Error("Can not use compression flags with format: ",
                             format.c_str());
        return 1;
      }
      if (nCompress > 1) {
        cmSystemTools::Error("Can only compress a tar file one way; "
                             "at most one flag of z, j, or J may be used");
        return 1;
      }
      if (flags.find_first_of('v') != flags.npos) {
        verbose = true;
      }

      if (flags.find_first_of('t') != flags.npos) {
        if (!cmSystemTools::ListTar(outFile.c_str(), verbose)) {
          cmSystemTools::Error("Problem listing tar: ", outFile.c_str());
          return 1;
        }
      } else if (flags.find_first_of('c') != flags.npos) {
        if (!cmSystemTools::CreateTar(outFile.c_str(), files, compress,
                                      verbose, mtime, format)) {
          cmSystemTools::Error("Problem creating tar: ", outFile.c_str());
          return 1;
        }
      } else if (flags.find_first_of('x') != flags.npos) {
        if (!cmSystemTools::ExtractTar(outFile.c_str(), verbose)) {
          cmSystemTools::Error("Problem extracting tar: ", outFile.c_str());
          return 1;
        }
#ifdef WIN32
        // OK, on windows 7 after we untar some files,
        // sometimes we can not rename the directory after
        // the untar is done. This breaks the external project
        // untar and rename code.  So, by default we will wait
        // 1/10th of a second after the untar.  If CMAKE_UNTAR_DELAY
        // is set in the env, its value will be used instead of 100.
        int delay = 100;
        std::string delayVar;
        if (cmSystemTools::GetEnv("CMAKE_UNTAR_DELAY", delayVar)) {
          delay = atoi(delayVar.c_str());
        }
        if (delay) {
          cmSystemTools::Delay(delay);
        }
#endif
      }
      return 0;
    }

    if (args[1] == "server") {
      const std::string pipePrefix = "--pipe=";
      bool supportExperimental = false;
      bool isDebug = false;
      std::string pipe;

      for (size_t i = 2; i < args.size(); ++i) {
        const std::string& a = args[i];

        if (a == "--experimental") {
          supportExperimental = true;
        } else if (a == "--debug") {
          pipe.clear();
          isDebug = true;
        } else if (a.substr(0, pipePrefix.size()) == pipePrefix) {
          isDebug = false;
          pipe = a.substr(pipePrefix.size());
          if (pipe.empty()) {
            cmSystemTools::Error("No pipe given after --pipe=");
            return 2;
          }
        } else {
          cmSystemTools::Error("Unknown argument for server mode");
          return 1;
        }
      }
#if defined(HAVE_SERVER_MODE) && HAVE_SERVER_MODE
      cmServerConnection* conn;
      if (isDebug) {
        conn = new cmServerStdIoConnection;
      } else {
        conn = new cmServerPipeConnection(pipe);
      }
      cmServer server(conn, supportExperimental);
      std::string errorMessage;
      if (server.Serve(&errorMessage)) {
        return 0;
      }
      cmSystemTools::Error(errorMessage.c_str());
#else
      static_cast<void>(supportExperimental);
      static_cast<void>(isDebug);
      cmSystemTools::Error("CMake was not built with server mode enabled");
#endif
      return 1;
    }

#if defined(CMAKE_BUILD_WITH_CMAKE)
    // Internal CMake Fortran module support.
    if (args[1] == "cmake_copy_f90_mod" && args.size() >= 4) {
      return cmDependsFortran::CopyModule(args) ? 0 : 1;
    }
#endif

#if defined(_WIN32) && !defined(__CYGWIN__)
    // Write registry value
    if (args[1] == "write_regv" && args.size() > 3) {
      return cmSystemTools::WriteRegistryValue(args[2].c_str(),
                                               args[3].c_str())
        ? 0
        : 1;
    }

    // Delete registry value
    if (args[1] == "delete_regv" && args.size() > 2) {
      return cmSystemTools::DeleteRegistryValue(args[2].c_str()) ? 0 : 1;
    }

    // Remove file
    if (args[1] == "comspec" && args.size() > 2) {
      std::cerr << "Win9x helper \"cmake -E comspec\" no longer supported\n";
      return 1;
    }

    if (args[1] == "env_vs8_wince" && args.size() == 3) {
      return cmcmd::WindowsCEEnvironment("8.0", args[2]);
    }

    if (args[1] == "env_vs9_wince" && args.size() == 3) {
      return cmcmd::WindowsCEEnvironment("9.0", args[2]);
    }
#endif
  }

  ::CMakeCommandUsage(args[0].c_str());
  return 1;
}

int cmcmd::SymlinkLibrary(std::vector<std::string>& args)
{
  int result = 0;
  std::string realName = args[2];
  std::string soName = args[3];
  std::string name = args[4];
  if (soName != realName) {
    if (!cmcmd::SymlinkInternal(realName, soName)) {
      cmSystemTools::ReportLastSystemError("cmake_symlink_library");
      result = 1;
    }
  }
  if (name != soName) {
    if (!cmcmd::SymlinkInternal(soName, name)) {
      cmSystemTools::ReportLastSystemError("cmake_symlink_library");
      result = 1;
    }
  }
  return result;
}

int cmcmd::SymlinkExecutable(std::vector<std::string>& args)
{
  int result = 0;
  std::string realName = args[2];
  std::string name = args[3];
  if (name != realName) {
    if (!cmcmd::SymlinkInternal(realName, name)) {
      cmSystemTools::ReportLastSystemError("cmake_symlink_executable");
      result = 1;
    }
  }
  return result;
}

bool cmcmd::SymlinkInternal(std::string const& file, std::string const& link)
{
  if (cmSystemTools::FileExists(link.c_str()) ||
      cmSystemTools::FileIsSymlink(link)) {
    cmSystemTools::RemoveFile(link);
  }
#if defined(_WIN32) && !defined(__CYGWIN__)
  return cmSystemTools::CopyFileAlways(file.c_str(), link.c_str());
#else
  std::string linktext = cmSystemTools::GetFilenameName(file);
  return cmSystemTools::CreateSymlink(linktext, link);
#endif
}

static void cmcmdProgressReport(std::string const& dir, std::string const& num)
{
  std::string dirName = dir;
  dirName += "/Progress";
  std::string fName;
  FILE* progFile;

  // read the count
  fName = dirName;
  fName += "/count.txt";
  progFile = cmsys::SystemTools::Fopen(fName, "r");
  int count = 0;
  if (!progFile) {
    return;
  }
  if (1 != fscanf(progFile, "%i", &count)) {
    cmSystemTools::Message("Could not read from progress file.");
  }
  fclose(progFile);

  const char* last = num.c_str();
  for (const char* c = last;; ++c) {
    if (*c == ',' || *c == '\0') {
      if (c != last) {
        fName = dirName;
        fName += "/";
        fName.append(last, c - last);
        progFile = cmsys::SystemTools::Fopen(fName, "w");
        if (progFile) {
          fprintf(progFile, "empty");
          fclose(progFile);
        }
      }
      if (*c == '\0') {
        break;
      }
      last = c + 1;
    }
  }
  int fileNum =
    static_cast<int>(cmsys::Directory::GetNumberOfFilesInDirectory(dirName));
  if (count > 0) {
    // print the progress
    fprintf(stdout, "[%3i%%] ", ((fileNum - 3) * 100) / count);
  }
}

int cmcmd::ExecuteEchoColor(std::vector<std::string>& args)
{
  // The arguments are
  //   argv[0] == <cmake-executable>
  //   argv[1] == cmake_echo_color

  bool enabled = true;
  int color = cmsysTerminal_Color_Normal;
  bool newline = true;
  std::string progressDir;
  for (unsigned int i = 2; i < args.size(); ++i) {
    if (args[i].find("--switch=") == 0) {
      // Enable or disable color based on the switch value.
      std::string value = args[i].substr(9);
      if (!value.empty()) {
        enabled = cmSystemTools::IsOn(value.c_str());
      }
    } else if (cmHasLiteralPrefix(args[i], "--progress-dir=")) {
      progressDir = args[i].substr(15);
    } else if (cmHasLiteralPrefix(args[i], "--progress-num=")) {
      if (!progressDir.empty()) {
        std::string const& progressNum = args[i].substr(15);
        cmcmdProgressReport(progressDir, progressNum);
      }
    } else if (args[i] == "--normal") {
      color = cmsysTerminal_Color_Normal;
    } else if (args[i] == "--black") {
      color = cmsysTerminal_Color_ForegroundBlack;
    } else if (args[i] == "--red") {
      color = cmsysTerminal_Color_ForegroundRed;
    } else if (args[i] == "--green") {
      color = cmsysTerminal_Color_ForegroundGreen;
    } else if (args[i] == "--yellow") {
      color = cmsysTerminal_Color_ForegroundYellow;
    } else if (args[i] == "--blue") {
      color = cmsysTerminal_Color_ForegroundBlue;
    } else if (args[i] == "--magenta") {
      color = cmsysTerminal_Color_ForegroundMagenta;
    } else if (args[i] == "--cyan") {
      color = cmsysTerminal_Color_ForegroundCyan;
    } else if (args[i] == "--white") {
      color = cmsysTerminal_Color_ForegroundWhite;
    } else if (args[i] == "--bold") {
      color |= cmsysTerminal_Color_ForegroundBold;
    } else if (args[i] == "--no-newline") {
      newline = false;
    } else if (args[i] == "--newline") {
      newline = true;
    } else {
      // Color is enabled.  Print with the current color.
      cmSystemTools::MakefileColorEcho(color, args[i].c_str(), newline,
                                       enabled);
    }
  }

  return 0;
}

int cmcmd::ExecuteLinkScript(std::vector<std::string>& args)
{
  // The arguments are
  //   argv[0] == <cmake-executable>
  //   argv[1] == cmake_link_script
  //   argv[2] == <link-script-name>
  //   argv[3] == --verbose=?
  bool verbose = false;
  if (args.size() >= 4) {
    if (args[3].find("--verbose=") == 0) {
      if (!cmSystemTools::IsOff(args[3].substr(10).c_str())) {
        verbose = true;
      }
    }
  }

  // Allocate a process instance.
  cmsysProcess* cp = cmsysProcess_New();
  if (!cp) {
    std::cerr << "Error allocating process instance in link script."
              << std::endl;
    return 1;
  }

  // Children should share stdout and stderr with this process.
  cmsysProcess_SetPipeShared(cp, cmsysProcess_Pipe_STDOUT, 1);
  cmsysProcess_SetPipeShared(cp, cmsysProcess_Pipe_STDERR, 1);

  // Run the command lines verbatim.
  cmsysProcess_SetOption(cp, cmsysProcess_Option_Verbatim, 1);

  // Read command lines from the script.
  cmsys::ifstream fin(args[2].c_str());
  if (!fin) {
    std::cerr << "Error opening link script \"" << args[2] << "\""
              << std::endl;
    return 1;
  }

  // Run one command at a time.
  std::string command;
  int result = 0;
  while (result == 0 && cmSystemTools::GetLineFromStream(fin, command)) {
    // Skip empty command lines.
    if (command.find_first_not_of(" \t") == command.npos) {
      continue;
    }

    // Setup this command line.
    const char* cmd[2] = { command.c_str(), CM_NULLPTR };
    cmsysProcess_SetCommand(cp, cmd);

    // Report the command if verbose output is enabled.
    if (verbose) {
      std::cout << command << std::endl;
    }

    // Run the command and wait for it to exit.
    cmsysProcess_Execute(cp);
    cmsysProcess_WaitForExit(cp, CM_NULLPTR);

    // Report failure if any.
    switch (cmsysProcess_GetState(cp)) {
      case cmsysProcess_State_Exited: {
        int value = cmsysProcess_GetExitValue(cp);
        if (value != 0) {
          result = value;
        }
      } break;
      case cmsysProcess_State_Exception:
        std::cerr << "Error running link command: "
                  << cmsysProcess_GetExceptionString(cp) << std::endl;
        result = 1;
        break;
      case cmsysProcess_State_Error:
        std::cerr << "Error running link command: "
                  << cmsysProcess_GetErrorString(cp) << std::endl;
        result = 2;
        break;
      default:
        break;
    };
  }

  // Free the process instance.
  cmsysProcess_Delete(cp);

  // Return the final resulting return value.
  return result;
}

int cmcmd::WindowsCEEnvironment(const char* version, const std::string& name)
{
#if defined(CMAKE_BUILD_WITH_CMAKE) && defined(_WIN32) && !defined(__CYGWIN__)
  cmVisualStudioWCEPlatformParser parser(name.c_str());
  parser.ParseVersion(version);
  if (parser.Found()) {
    std::cout << "@echo off" << std::endl;
    std::cout << "echo Environment Selection: " << name << std::endl;
    std::cout << "set PATH=" << parser.GetPathDirectories() << std::endl;
    std::cout << "set INCLUDE=" << parser.GetIncludeDirectories() << std::endl;
    std::cout << "set LIB=" << parser.GetLibraryDirectories() << std::endl;
    return 0;
  }
#else
  (void)version;
#endif

  std::cerr << "Could not find " << name;
  return -1;
}

class cmVSLink
{
  int Type;
  bool Verbose;
  bool Incremental;
  bool LinkGeneratesManifest;
  std::vector<std::string> LinkCommand;
  std::vector<std::string> UserManifests;
  std::string LinkerManifestFile;
  std::string ManifestFile;
  std::string ManifestFileRC;
  std::string ManifestFileRes;
  std::string TargetFile;

public:
  cmVSLink(int type, bool verbose)
    : Type(type)
    , Verbose(verbose)
    , Incremental(false)
    , LinkGeneratesManifest(true)
  {
  }
  bool Parse(std::vector<std::string>::const_iterator argBeg,
             std::vector<std::string>::const_iterator argEnd);
  int Link();

private:
  int LinkIncremental();
  int LinkNonIncremental();
  int RunMT(std::string const& out, bool notify);
};

// For visual studio 2005 and newer manifest files need to be embedded into
// exe and dll's.  This code does that in such a way that incremental linking
// still works.
int cmcmd::VisualStudioLink(std::vector<std::string>& args, int type)
{
  if (args.size() < 2) {
    return -1;
  }
  const bool verbose = cmSystemTools::HasEnv("VERBOSE");
  std::vector<std::string> expandedArgs;
  for (std::vector<std::string>::iterator i = args.begin(); i != args.end();
       ++i) {
    // check for nmake temporary files
    if ((*i)[0] == '@' && i->find("@CMakeFiles") != 0) {
      cmsys::ifstream fin(i->substr(1).c_str());
      std::string line;
      while (cmSystemTools::GetLineFromStream(fin, line)) {
        cmSystemTools::ParseWindowsCommandLine(line.c_str(), expandedArgs);
      }
    } else {
      expandedArgs.push_back(*i);
    }
  }

  cmVSLink vsLink(type, verbose);
  if (!vsLink.Parse(expandedArgs.begin() + 2, expandedArgs.end())) {
    return -1;
  }
  return vsLink.Link();
}

static bool RunCommand(const char* comment, std::vector<std::string>& command,
                       bool verbose, int* retCodeOut = CM_NULLPTR)
{
  if (verbose) {
    std::cout << comment << ":\n";
    std::cout << cmJoin(command, " ") << "\n";
  }
  std::string output;
  int retCode = 0;
  // use rc command to create .res file
  bool res =
    cmSystemTools::RunSingleCommand(command, &output, &output, &retCode,
                                    CM_NULLPTR, cmSystemTools::OUTPUT_NONE);
  // always print the output of the command, unless
  // it is the dumb rc command banner, but if the command
  // returned an error code then print the output anyway as
  // the banner may be mixed with some other important information.
  if (output.find("Resource Compiler Version") == output.npos || !res ||
      retCode) {
    std::cout << output;
  }
  if (!res) {
    std::cout << comment << " failed to run." << std::endl;
    return false;
  }
  // if retCodeOut is requested then always return true
  // and set the retCodeOut to retCode
  if (retCodeOut) {
    *retCodeOut = retCode;
    return true;
  }
  if (retCode != 0) {
    std::cout << comment << " failed. with " << retCode << "\n";
  }
  return retCode == 0;
}

bool cmVSLink::Parse(std::vector<std::string>::const_iterator argBeg,
                     std::vector<std::string>::const_iterator argEnd)
{
  // Parse our own arguments.
  std::string intDir;
  std::vector<std::string>::const_iterator arg = argBeg;
  while (arg != argEnd && cmHasLiteralPrefix(*arg, "-")) {
    if (*arg == "--") {
      ++arg;
      break;
    }
    if (*arg == "--manifests") {
      for (++arg; arg != argEnd && !cmHasLiteralPrefix(*arg, "-"); ++arg) {
        this->UserManifests.push_back(*arg);
      }
    } else if (cmHasLiteralPrefix(*arg, "--intdir=")) {
      intDir = arg->substr(9);
      ++arg;
    } else {
      std::cerr << "unknown argument '" << *arg << "'\n";
      return false;
    }
  }
  if (intDir.empty()) {
    return false;
  }

  // The rest of the arguments form the link command.
  if (arg == argEnd) {
    return false;
  }
  this->LinkCommand.insert(this->LinkCommand.begin(), arg, argEnd);

  // Parse the link command to extract information we need.
  for (; arg != argEnd; ++arg) {
    if (cmSystemTools::Strucmp(arg->c_str(), "/INCREMENTAL:YES") == 0) {
      this->Incremental = true;
    } else if (cmSystemTools::Strucmp(arg->c_str(), "/INCREMENTAL") == 0) {
      this->Incremental = true;
    } else if (cmSystemTools::Strucmp(arg->c_str(), "/MANIFEST:NO") == 0) {
      this->LinkGeneratesManifest = false;
    } else if (cmHasLiteralPrefix(*arg, "/Fe")) {
      this->TargetFile = arg->substr(3);
    } else if (cmHasLiteralPrefix(*arg, "/out:")) {
      this->TargetFile = arg->substr(5);
    }
  }

  if (this->TargetFile.empty()) {
    return false;
  }

  this->ManifestFile = intDir + "/embed.manifest";
  this->LinkerManifestFile = intDir + "/intermediate.manifest";

  if (this->Incremental) {
    // We will compile a resource containing the manifest and
    // pass it to the link command.
    this->ManifestFileRC = intDir + "/manifest.rc";
    this->ManifestFileRes = intDir + "/manifest.res";
  } else if (this->UserManifests.empty()) {
    // Prior to support for user-specified manifests CMake placed the
    // linker-generated manifest next to the binary (as if it were not to be
    // embedded) when not linking incrementally.  Preserve this behavior.
    this->ManifestFile = this->TargetFile + ".manifest";
    this->LinkerManifestFile = this->ManifestFile;
  }

  if (this->LinkGeneratesManifest) {
    this->LinkCommand.push_back("/MANIFEST");
    this->LinkCommand.push_back("/MANIFESTFILE:" + this->LinkerManifestFile);
  }

  return true;
}

int cmVSLink::Link()
{
  if (this->Incremental &&
      (this->LinkGeneratesManifest || !this->UserManifests.empty())) {
    if (this->Verbose) {
      std::cout << "Visual Studio Incremental Link with embedded manifests\n";
    }
    return LinkIncremental();
  }
  if (this->Verbose) {
    if (!this->Incremental) {
      std::cout << "Visual Studio Non-Incremental Link\n";
    } else {
      std::cout << "Visual Studio Incremental Link without manifests\n";
    }
  }
  return LinkNonIncremental();
}

int cmVSLink::LinkIncremental()
{
  // This follows the steps listed here:
  // http://blogs.msdn.com/zakramer/archive/2006/05/22/603558.aspx

  //    1.  Compiler compiles the application and generates the *.obj files.
  //    2.  An empty manifest file is generated if this is a clean build and if
  //    not the previous one is reused.
  //    3.  The resource compiler (rc.exe) compiles the *.manifest file to a
  //    *.res file.
  //    4.  Linker generates the binary (EXE or DLL) with the /incremental
  //    switch and embeds the dummy manifest file. The linker also generates
  //    the real manifest file based on the binaries that your binary depends
  //    on.
  //    5.  The manifest tool (mt.exe) is then used to generate the final
  //    manifest.

  // If the final manifest is changed, then 6 and 7 are run, if not
  // they are skipped, and it is done.

  //    6.  The resource compiler is invoked one more time.
  //    7.  Finally, the Linker does another incremental link, but since the
  //    only thing that has changed is the *.res file that contains the
  //    manifest it is a short link.

  // Create a resource file referencing the manifest.
  std::string absManifestFile =
    cmSystemTools::CollapseFullPath(this->ManifestFile);
  if (this->Verbose) {
    std::cout << "Create " << this->ManifestFileRC << "\n";
  }
  {
    cmsys::ofstream fout(this->ManifestFileRC.c_str());
    if (!fout) {
      return -1;
    }
    fout << this->Type << " /* CREATEPROCESS_MANIFEST_RESOURCE_ID */ "
                          "24 /* RT_MANIFEST */ \""
         << absManifestFile << "\"";
  }

  // If we have not previously generated a manifest file,
  // generate an empty one so the resource compiler succeeds.
  if (!cmSystemTools::FileExists(this->ManifestFile)) {
    if (this->Verbose) {
      std::cout << "Create empty: " << this->ManifestFile << "\n";
    }
    cmsys::ofstream foutTmp(this->ManifestFile.c_str());
  }

  // Compile the resource file.
  std::vector<std::string> rcCommand;
  rcCommand.push_back(cmSystemTools::FindProgram("rc.exe"));
  rcCommand.push_back("/fo" + this->ManifestFileRes);
  rcCommand.push_back(this->ManifestFileRC);
  if (!RunCommand("RC Pass 1", rcCommand, this->Verbose)) {
    return -1;
  }

  // Tell the linker to use our manifest compiled into a resource.
  this->LinkCommand.push_back(this->ManifestFileRes);

  // Run the link command (possibly generates intermediate manifest).
  if (!RunCommand("LINK Pass 1", this->LinkCommand, this->Verbose)) {
    return -1;
  }

  // Run the manifest tool to create the final manifest.
  int mtRet = this->RunMT("/out:" + this->ManifestFile, true);

  // If mt returns 1090650113 (or 187 on a posix host) then it updated the
  // manifest file so we need to embed it again.  Otherwise we are done.
  if (mtRet != 1090650113 && mtRet != 187) {
    return mtRet;
  }

  // Compile the resource file again.
  if (!RunCommand("RC Pass 2", rcCommand, this->Verbose)) {
    return -1;
  }

  // Link incrementally again to use the updated resource.
  if (!RunCommand("FINAL LINK", this->LinkCommand, this->Verbose)) {
    return -1;
  }
  return 0;
}

int cmVSLink::LinkNonIncremental()
{
  // Run the link command (possibly generates intermediate manifest).
  if (!RunCommand("LINK", this->LinkCommand, this->Verbose)) {
    return -1;
  }

  // If we have no manifest files we are done.
  if (!this->LinkGeneratesManifest && this->UserManifests.empty()) {
    return 0;
  }

  // Run the manifest tool to embed the final manifest in the binary.
  std::string mtOut =
    "/outputresource:" + this->TargetFile + (this->Type == 1 ? ";#1" : ";#2");
  return this->RunMT(mtOut, false);
}

int cmVSLink::RunMT(std::string const& out, bool notify)
{
  std::vector<std::string> mtCommand;
  mtCommand.push_back(cmSystemTools::FindProgram("mt.exe"));
  mtCommand.push_back("/nologo");
  mtCommand.push_back("/manifest");
  if (this->LinkGeneratesManifest) {
    mtCommand.push_back(this->LinkerManifestFile);
  }
  mtCommand.insert(mtCommand.end(), this->UserManifests.begin(),
                   this->UserManifests.end());
  mtCommand.push_back(out);
  if (notify) {
    // Add an undocumented option that enables a special return
    // code to notify us when the manifest is modified.
    mtCommand.push_back("/notify_update");
  }
  int mtRet = 0;
  if (!RunCommand("MT", mtCommand, this->Verbose, &mtRet)) {
    return -1;
  }
  return mtRet;
}