package org.codehaus.mojo.natives.linker;
   
   /*
    * The MIT License
    *
    * Copyright (c) 2004, The Codehaus
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy of
    * this software and associated documentation files (the "Software"), to deal in
   * the Software without restriction, including without limitation the rights to
   * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
   * of the Software, and to permit persons to whom the Software is furnished to do
   * so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  import java.io.File;
  import java.io.IOException;
  import java.util.List;
  
  import org.codehaus.mojo.natives.NativeBuildException;
  import org.codehaus.mojo.natives.util.CommandLineUtil;
  import org.codehaus.mojo.natives.util.EnvUtil;
  import org.codehaus.plexus.logging.AbstractLogEnabled;
  import org.codehaus.plexus.util.cli.Commandline;
  
  public abstract class AbstractLinker
      extends AbstractLogEnabled
      implements Linker
  {
  
      protected abstract Commandline createLinkerCommandLine( List objectFiles, LinkerConfiguration config )
          throws NativeBuildException;
  
      public File link( LinkerConfiguration config, List compilerOutputFiles )
          throws NativeBuildException, IOException
      {
          if ( isStaled( config, compilerOutputFiles ) )
          {
              // TODO validate config to make sure required fields are available
              Commandline cl = this.createLinkerCommandLine( compilerOutputFiles, config );
              EnvUtil.setupCommandlineEnv( cl, config.getEnvFactory() );
              CommandLineUtil.execute( cl, this.getLogger() );
          }
  
          return config.getOutputFile();
      }
  
      private boolean isStaled( LinkerConfiguration config, List compilerOutputFiles )
      {
          if ( !config.isCheckStaleLinkage() )
          {
              // user dont care
              return true;
          }
  
          File previousDestination = config.getOutputFile();
  
          if ( !previousDestination.exists() )
          {
              return true;
          }
  
          if ( previousDestination.exists() )
          {
              for ( int i = 0; i < compilerOutputFiles.size(); ++i )
              {
                  if ( previousDestination.lastModified() < ( (File) compilerOutputFiles.get( i ) ).lastModified() )
                  {
                      if ( this.getLogger().isDebugEnabled() )
                      {
                          getLogger().debug( "Stale relative to compilerOutputFiles: "
                                                 + ( (File) compilerOutputFiles.get( i ) ).getAbsolutePath() );
                      }
  
                      return true;
                  }
              }
  
              for ( int i = 0; i < config.getExternalLibFileNames().size(); ++i )
              {
                  File extLib =
                      new File( config.getExternalLibDirectory(), (String) config.getExternalLibFileNames().get( i ) );
  
                  if ( previousDestination.lastModified() < extLib.lastModified() )
                  {
                      if ( this.getLogger().isDebugEnabled() )
                      {
                          getLogger().debug( "Stale relative to extLib: " + extLib.getAbsolutePath() );
                     }
 
                     return true;
                 }
             }
         }
 
         return false;
     }
 
 }