private Set<File> computeStaleSources( CompilerConfiguration compilerConfiguration, Compiler compiler,
SourceInclusionScanner scanner )
throws MojoExecutionException, CompilerException
{
SourceMapping mapping = getSourceMapping( compilerConfiguration, compiler );
File outputDirectory;
CompilerOutputStyle outputStyle = compiler.getCompilerOutputStyle();
if ( outputStyle == CompilerOutputStyle.ONE_OUTPUT_FILE_FOR_ALL_INPUT_FILES )
{