for (File f : FileSetUtils.convertFileSetToFiles(source)) {
command.add(f.getCanonicalPath());
}
exec = new Exec(this);
out = new ArrayList<String>();
if (exec.run(command, out) != 0) {
getLog().error("protoc compiler error");
for (String s : out) {
getLog().error(s);
}
throw new MojoExecutionException("protoc failure");