CMake/Source/cmGeneratedFileStream.cxx

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

#include "cmSystemTools.h"

#include <stdio.h>

#if defined(CMAKE_BUILD_WITH_CMAKE)
#include <cm_zlib.h>
#endif

cmGeneratedFileStream::cmGeneratedFileStream()
  : cmGeneratedFileStreamBase()
  , Stream()
{
}

cmGeneratedFileStream::cmGeneratedFileStream(const char* name, bool quiet)
  : cmGeneratedFileStreamBase(name)
  , Stream(TempName.c_str())
{
  // Check if the file opened.
  if (!*this && !quiet) {
    cmSystemTools::Error("Cannot open file for write: ",
                         this->TempName.c_str());
    cmSystemTools::ReportLastSystemError("");
  }
}

cmGeneratedFileStream::~cmGeneratedFileStream()
{
  // This is the first destructor called.  Check the status of the
  // stream and give the information to the private base.  Next the
  // stream will be destroyed which will close the temporary file.
  // Finally the base destructor will be called to replace the
  // destination file.
  this->Okay = !this->fail();
}

cmGeneratedFileStream& cmGeneratedFileStream::Open(const char* name,
                                                   bool quiet, bool binaryFlag)
{
  // Store the file name and construct the temporary file name.
  this->cmGeneratedFileStreamBase::Open(name);

  // Open the temporary output file.
  if (binaryFlag) {
    this->Stream::open(this->TempName.c_str(),
                       std::ios::out | std::ios::binary);
  } else {
    this->Stream::open(this->TempName.c_str());
  }

  // Check if the file opened.
  if (!*this && !quiet) {
    cmSystemTools::Error("Cannot open file for write: ",
                         this->TempName.c_str());
    cmSystemTools::ReportLastSystemError("");
  }
  return *this;
}

bool cmGeneratedFileStream::Close()
{
  // Save whether the temporary output file is valid before closing.
  this->Okay = !this->fail();

  // Close the temporary output file.
  this->Stream::close();

  // Remove the temporary file (possibly by renaming to the real file).
  return this->cmGeneratedFileStreamBase::Close();
}

void cmGeneratedFileStream::SetCopyIfDifferent(bool copy_if_different)
{
  this->CopyIfDifferent = copy_if_different;
}

void cmGeneratedFileStream::SetCompression(bool compression)
{
  this->Compress = compression;
}

void cmGeneratedFileStream::SetCompressionExtraExtension(bool ext)
{
  this->CompressExtraExtension = ext;
}

cmGeneratedFileStreamBase::cmGeneratedFileStreamBase()
  : Name()
  , TempName()
  , CopyIfDifferent(false)
  , Okay(false)
  , Compress(false)
  , CompressExtraExtension(true)
{
}

cmGeneratedFileStreamBase::cmGeneratedFileStreamBase(const char* name)
  : Name()
  , TempName()
  , CopyIfDifferent(false)
  , Okay(false)
  , Compress(false)
  , CompressExtraExtension(true)
{
  this->Open(name);
}

cmGeneratedFileStreamBase::~cmGeneratedFileStreamBase()
{
  this->Close();
}

void cmGeneratedFileStreamBase::Open(const char* name)
{
  // Save the original name of the file.
  this->Name = name;

  // Create the name of the temporary file.
  this->TempName = name;
#if defined(__VMS)
  this->TempName += "_tmp";
#else
  this->TempName += ".tmp";
#endif

  // Make sure the temporary file that will be used is not present.
  cmSystemTools::RemoveFile(this->TempName);

  std::string dir = cmSystemTools::GetFilenamePath(this->TempName);
  cmSystemTools::MakeDirectory(dir.c_str());
}

bool cmGeneratedFileStreamBase::Close()
{
  bool replaced = false;

  std::string resname = this->Name;
  if (this->Compress && this->CompressExtraExtension) {
    resname += ".gz";
  }

  // Only consider replacing the destination file if no error
  // occurred.
  if (!this->Name.empty() && this->Okay &&
      (!this->CopyIfDifferent ||
       cmSystemTools::FilesDiffer(this->TempName, resname))) {
    // The destination is to be replaced.  Rename the temporary to the
    // destination atomically.
    if (this->Compress) {
      std::string gzname = this->TempName + ".temp.gz";
      if (this->CompressFile(this->TempName.c_str(), gzname.c_str())) {
        this->RenameFile(gzname.c_str(), resname.c_str());
      }
      cmSystemTools::RemoveFile(gzname);
    } else {
      this->RenameFile(this->TempName.c_str(), resname.c_str());
    }

    replaced = true;
  }

  // Else, the destination was not replaced.
  //
  // Always delete the temporary file. We never want it to stay around.
  cmSystemTools::RemoveFile(this->TempName);

  return replaced;
}

#ifdef CMAKE_BUILD_WITH_CMAKE
int cmGeneratedFileStreamBase::CompressFile(const char* oldname,
                                            const char* newname)
{
  gzFile gf = gzopen(newname, "w");
  if (!gf) {
    return 0;
  }
  FILE* ifs = cmsys::SystemTools::Fopen(oldname, "r");
  if (!ifs) {
    return 0;
  }
  size_t res;
  const size_t BUFFER_SIZE = 1024;
  char buffer[BUFFER_SIZE];
  while ((res = fread(buffer, 1, BUFFER_SIZE, ifs)) > 0) {
    if (!gzwrite(gf, buffer, static_cast<int>(res))) {
      fclose(ifs);
      gzclose(gf);
      return 0;
    }
  }
  fclose(ifs);
  gzclose(gf);
  return 1;
}
#else
int cmGeneratedFileStreamBase::CompressFile(const char*, const char*)
{
  return 0;
}
#endif

int cmGeneratedFileStreamBase::RenameFile(const char* oldname,
                                          const char* newname)
{
  return cmSystemTools::RenameFile(oldname, newname);
}

void cmGeneratedFileStream::SetName(const std::string& fname)
{
  this->Name = fname;
}