CTest: adopt std::chrono::system_clock

After the refactor to make CTest use std::chrono::steady_clock for the
keeping of time for test duration, there are still references to
cmSystemTools::GetTime() left.
To further adopt std::chrono for time related activities, this commit
changes those remaining references to std::chrono::system_clock::now()
calls and alters the storage from either unsigned int or double to
std::chrono::system_clock::time_point.

For ease of conversion, a converter method is added to cmXMLWriter that
converts from a std::chrono::system_clock::time_point to the number of
seconds since the UN*X epoch as that is expected behaviour. This means
no more casts as required.

Functionally should be no difference as the system_clock is implemented
in the same terms.

1 files changed, 6 insertions, 10 deletions

diff --git a/Source/CTest/cmCTestCoverageHandler.cxx b/Source/CTest/cmCTestCoverageHandler.cxx
index 85f6ce9..bbfe9bd 100644
--- a/Source/CTest/cmCTestCoverageHandler.cxx
+++ b/Source/CTest/cmCTestCoverageHandler.cxx
@@ -175,14 +175,13 @@ void cmCTestCoverageHandler::StartCoverageLogXML(cmXMLWriter& xml)
   this->CTest->StartXML(xml, this->AppendXML);
   xml.StartElement("CoverageLog");
   xml.Element("StartDateTime", this->CTest->CurrentTime());
-  xml.Element("StartTime",
-              static_cast<unsigned int>(cmSystemTools::GetTime()));
+  xml.Element("StartTime", std::chrono::system_clock::now());
 }
 
 void cmCTestCoverageHandler::EndCoverageLogXML(cmXMLWriter& xml)
 {
   xml.Element("EndDateTime", this->CTest->CurrentTime());
-  xml.Element("EndTime", static_cast<unsigned int>(cmSystemTools::GetTime()));
+  xml.Element("EndTime", std::chrono::system_clock::now());
   xml.EndElement(); // CoverageLog
   this->CTest->EndXML(xml);
 }
@@ -283,8 +282,7 @@ int cmCTestCoverageHandler::ProcessHandler()
   }
 
   std::string coverage_start_time = this->CTest->CurrentTime();
-  unsigned int coverage_start_time_time =
-    static_cast<unsigned int>(cmSystemTools::GetTime());
+  auto coverage_start_time_time = std::chrono::system_clock::now();
   std::string sourceDir =
     this->CTest->GetCTestConfiguration("SourceDirectory");
   std::string binaryDir = this->CTest->GetCTestConfiguration("BuildDirectory");
@@ -622,8 +620,7 @@ int cmCTestCoverageHandler::ProcessHandler()
   covSumXML.Element("LOC", total_lines);
   covSumXML.Element("PercentCoverage", percent_coverage);
   covSumXML.Element("EndDateTime", end_time);
-  covSumXML.Element("EndTime",
-                    static_cast<unsigned int>(cmSystemTools::GetTime()));
+  covSumXML.Element("EndTime", std::chrono::system_clock::now());
   covSumXML.Element("ElapsedMinutes",
                     std::chrono::duration_cast<std::chrono::minutes>(
                       std::chrono::steady_clock::now() - elapsed_time_start)
@@ -1970,8 +1967,7 @@ int cmCTestCoverageHandler::RunBullseyeSourceSummary(
   std::string coverage_start_time = this->CTest->CurrentTime();
   xml.StartElement("Coverage");
   xml.Element("StartDateTime", coverage_start_time);
-  xml.Element("StartTime",
-              static_cast<unsigned int>(cmSystemTools::GetTime()));
+  xml.Element("StartTime", std::chrono::system_clock::now());
   std::string stdline;
   std::string errline;
   // expected output:
@@ -2092,7 +2088,7 @@ int cmCTestCoverageHandler::RunBullseyeSourceSummary(
   xml.Element("LOC", total_functions);
   xml.Element("PercentCoverage", SAFEDIV(percent_coverage, number_files));
   xml.Element("EndDateTime", end_time);
-  xml.Element("EndTime", static_cast<unsigned int>(cmSystemTools::GetTime()));
+  xml.Element("EndTime", std::chrono::system_clock::now());
   xml.Element("ElapsedMinutes",
               std::chrono::duration_cast<std::chrono::minutes>(
                 std::chrono::steady_clock::now() - elapsed_time_start)