class WatchFile: Remember a files attributes to detect content changes.

diff --git a/zypp/base/WatchFile.h b/zypp/base/WatchFile.h
new file mode 100644 (file)
index 0000000..2597a4c
--- /dev/null
+++ b/zypp/base/WatchFile.h
@@ -0,0 +1,90 @@
+/*---------------------------------------------------------------------\
+|                          ____ _   __ __ ___                          |
+|                         |__  / \ / / . \ . \                         |
+|                           / / \ V /|  _/  _/                         |
+|                          / /__ | | | | | |                           |
+|                         /_____||_| |_| |_|                           |
+|                                                                      |
+\---------------------------------------------------------------------*/
+/** \file      zypp/base/WatchFile.h
+ *
+*/
+#ifndef ZYPP_BASE_WATCHFILE_H
+#define ZYPP_BASE_WATCHFILE_H
+
+#include <iosfwd>
+
+#include "zypp/PathInfo.h"
+
+///////////////////////////////////////////////////////////////////
+namespace zypp
+{ /////////////////////////////////////////////////////////////////
+
+  ///////////////////////////////////////////////////////////////////
+  //
+  //   CLASS NAME : WatchFile
+  //
+  /** Remember a files attributes to detect content changes.
+   *
+   * Repeatedly call \ref hasChanged to check whether the content has
+   * changed since the last call. Creation or deletion of the file will
+   * be reported as change as well.
+   *
+   * Per default the ctor stats the file, so \ref hasChanged will detect
+   * changes done after \ref WatchFile was created.
+   *
+   * You may omit the initial stat by passing \c NO_INIT as second argument
+   * to the ctor. \ref WatchFile  will behave as if the file did not exist
+   * at the time \ref WatchFile was created.
+   *
+   * \code
+   * static WatchFile sysconfigFile( "/etc/sysconfig/SuSEfirewall2",
+   *                                 WatchFile::NO_INIT );
+   * if ( sysconfigFile.hasChanged() )
+   * {
+   *   // releoad the file...
+   * }
+   * \endcode
+  */
+  class WatchFile
+  {
+    public:
+      enum Initial { NO_INIT, INIT };
+
+    public:
+      /** */
+      WatchFile( const Pathname & path_r = Pathname(),
+                Initial mode            = INIT )
+      : _path( path_r )
+      {
+       PathInfo pi( mode == INIT ? path_r : Pathname() );
+       _size  = pi.size();
+       _mtime = pi.mtime();
+      }
+
+      const Pathname & path() const
+      { return _path; }
+
+      bool hasChanged()
+      {
+       PathInfo pi( _path );
+       if ( _size != pi.size() || _mtime != pi.mtime() )
+       {
+         _size = pi.size();
+         _mtime = pi.mtime();
+         return true;
+       }
+       return false;
+      }
+
+    private:
+      Pathname _path;
+      off_t  _size;
+      time_t _mtime;
+  };
+  ///////////////////////////////////////////////////////////////////
+
+  /////////////////////////////////////////////////////////////////
+} // namespace zypp
+///////////////////////////////////////////////////////////////////
+#endif // ZYPP_BASE_WATCHFILE_H