paludis  Version 2.6.0
example_contents.cc

This example demonstrates how to use contents. It displays details about the files installed by 'sys-apps/paludis'.

/* vim: set sw=4 sts=4 et foldmethod=syntax : */
/** \file
*
* Example \ref example_contents.cc "example_contents.cc" .
*
* \ingroup g_contents
*/
/** \example example_contents.cc
*
* This example demonstrates how to use contents. It displays details about
* the files installed by 'sys-apps/paludis'.
*/
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cstdlib>
using namespace paludis;
using namespace examples;
using std::cout;
using std::endl;
using std::left;
using std::setw;
namespace
{
/* This visitor displays information about ContentsEntry subclasses. */
class ContentsPrinter
{
public:
void visit(const ContentsFileEntry & d)
{
cout << left << setw(10) << "file" << d.location_key()->parse_value() << endl;
}
void visit(const ContentsDirEntry & d)
{
cout << left << setw(10) << "dir" << d.location_key()->parse_value() << endl;
}
void visit(const ContentsSymEntry & d)
{
cout << left << setw(10) << "sym" << d.location_key()->parse_value()
<< " -> " << d.target_key()->parse_value() << endl;
}
void visit(const ContentsOtherEntry & d)
{
cout << left << setw(10) << "other" << d.location_key()->parse_value() << endl;
}
};
}
int main(int argc, char * argv[])
{
int exit_status(0);
try
{
CommandLine::get_instance()->run(argc, argv,
"example_contents", "EXAMPLE_CONTENTS_OPTIONS", "EXAMPLE_CONTENTS_CMDLINE");
/* We start with an Environment, respecting the user's '--environment' choice. */
std::shared_ptr<Environment> env(EnvironmentFactory::get_instance()->create(
CommandLine::get_instance()->a_environment.argument()));
/* Fetch package IDs for installed 'sys-apps/paludis'. */
std::shared_ptr<const PackageIDSequence> ids((*env)[selection::AllVersionsSorted(
/* For each ID: */
for (PackageIDSequence::ConstIterator i(ids->begin()), i_end(ids->end()) ;
i != i_end ; ++i)
{
/* Do we have contents key?*/
auto contents((*i)->contents());
if (! contents)
{
cout << "ID '" << **i << "' does not provide a contents key." << endl;
}
else
{
cout << "ID '" << **i << "' provides contents key:" << endl;
/* Visit the contents key's value's entries with our visitor. We use
* indirect_iterator because choices->begin() and ->end() return
* iterators to std::shared_ptr<>s rather than raw objects. */
ContentsPrinter p;
std::for_each(
indirect_iterator(contents->begin()),
indirect_iterator(contents->end()),
}
cout << endl;
}
}
catch (const Exception & e)
{
/* Paludis exceptions can provide a handy human-readable backtrace and
* an explanation message. Where possible, these should be displayed. */
cout << endl;
cout << "Unhandled exception:" << endl
<< " * " << e.backtrace("\n * ")
<< e.message() << " (" << e.what() << ")" << endl;
return EXIT_FAILURE;
}
catch (const std::exception & e)
{
cout << endl;
cout << "Unhandled exception:" << endl
<< " * " << e.what() << endl;
return EXIT_FAILURE;
}
catch (...)
{
cout << endl;
cout << "Unhandled exception:" << endl
<< " * Unknown exception type. Ouch..." << endl;
return EXIT_FAILURE;
}
return exit_status;
}