Code Salvage

- Integrated some code from the (soon to be obsolete) 2.0.0 branch,
  which is general in nature and will be needed.
- And the corresponding unit tests.

src/Sensor.cpp

@@ -0,0 +1,93 @@
+////////////////////////////////////////////////////////////////////////////////
+// taskwarrior - a command line task list manager.
+//
+// Copyright 2010, Paul Beckingham, Federico Hernandez.
+// All rights reserved.
+//
+// This program is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free Software
+// Foundation; either version 2 of the License, or (at your option) any later
+// version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+// details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program; if not, write to the
+//
+//     Free Software Foundation, Inc.,
+//     51 Franklin Street, Fifth Floor,
+//     Boston, MA
+//     02110-1301
+//     USA
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include <sys/stat.h>
+#include "Sensor.h"
+
+////////////////////////////////////////////////////////////////////////////////
+Sensor::Sensor ()
+: _changed (false)
+, _file ("")
+, _was (0)
+, _is (0)
+{
+}
+
+////////////////////////////////////////////////////////////////////////////////
+Sensor::~Sensor ()
+{
+}
+
+////////////////////////////////////////////////////////////////////////////////
+bool Sensor::changed ()
+{
+  _is = getModification ();
+  if (_is != _was)
+    _changed = true;
+
+  return _changed;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+void Sensor::reset ()
+{
+  _changed = false;
+  _was = _is;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/*
+void Sensor::fileCreation (const std::string&)
+{
+}
+*/
+
+////////////////////////////////////////////////////////////////////////////////
+void Sensor::fileModification (const std::string& file)
+{
+  _file = file;
+  _was  = getModification ();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/*
+void Sensor::fileDeletion (const std::string&)
+{
+}
+*/
+
+////////////////////////////////////////////////////////////////////////////////
+time_t Sensor::getModification ()
+{
+  struct stat s = {0};
+  if (0 == stat (_file.c_str (), &s))
+    return s.st_mtime;
+
+  return 0;
+}
+
+////////////////////////////////////////////////////////////////////////////////