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

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

#include "cmFileTimeCache.h"

#include <string>

#include <unordered_map>

#include <utility>

cmFileTimeCache::cmFileTimeCache() = default;

cmFileTimeCache::~cmFileTimeCache() = default;

bool cmFileTimeCache::Load(std::string const& fileName, cmFileTime& fileTime)

{

  // Use the stored time if available.

  {

    auto fit = this->Cache.find(fileName);

    if (fit != this->Cache.end()) {

      fileTime = fit->second;

      return true;

    }

  }

  // Read file time from OS

  if (!fileTime.Load(fileName)) {

    return false;

  }

  // Store file time in cache

  this->Cache[fileName] = fileTime;

  return true;

}

bool cmFileTimeCache::Remove(std::string const& fileName)

{

  return (this->Cache.erase(fileName) != 0);

}

bool cmFileTimeCache::Compare(std::string const& f1, std::string const& f2,

                              int* result)

{

  // Get the modification time for each file.

  cmFileTime ft1;

  cmFileTime ft2;

  if (this->Load(f1, ft1) && this->Load(f2, ft2)) {

    // Compare the two modification times.

    *result = ft1.Compare(ft2);

    return true;

  }

  // No comparison available.  Default to the same time.

  *result = 0;

  return false;

}

bool cmFileTimeCache::DifferS(std::string const& f1, std::string const& f2)

{

  // Get the modification time for each file.

  cmFileTime ft1;

  cmFileTime ft2;

  if (this->Load(f1, ft1) && this->Load(f2, ft2)) {

    // Compare the two modification times.

    return ft1.DifferS(ft2);

  }

  // No comparison available.  Default to different times.

  return true;

}