123 lines
4.4 KiB
C++
123 lines
4.4 KiB
C++
/* vim: set sw=4 sts=4 et foldmethod=syntax : */
|
|
|
|
/** \file
|
|
*
|
|
* Example \ref example_selection.cc "example_selection.cc" .
|
|
*
|
|
* \ingroup g_selection
|
|
*/
|
|
|
|
/** \example example_selection.cc
|
|
*
|
|
* This example demonstrates how to use the standard Selection, Generator and
|
|
* Filter classes.
|
|
**/
|
|
|
|
#include <paludis/paludis.hh>
|
|
#include "example_command_line.hh"
|
|
#include <iostream>
|
|
#include <algorithm>
|
|
#include <iterator>
|
|
#include <cstdlib>
|
|
|
|
using namespace paludis;
|
|
using namespace examples;
|
|
|
|
using std::cout;
|
|
using std::endl;
|
|
|
|
namespace
|
|
{
|
|
/* Run a particular selection, and show its results. */
|
|
void show_selection(const std::shared_ptr<const Environment> & env, const Selection & selection)
|
|
{
|
|
/* Selections support a crude form of stringification. */
|
|
cout << selection << ":" << endl;
|
|
|
|
/* Usually the only thing clients will do with a Selection object is pass it
|
|
* to Environment::operator[]. */
|
|
std::shared_ptr<const PackageIDSequence> ids((*env)[selection]);
|
|
|
|
/* Show the results */
|
|
if (! ids->empty())
|
|
std::copy(indirect_iterator(ids->begin()), indirect_iterator(ids->end()),
|
|
std::ostream_iterator<const PackageID>(cout, "\n"));
|
|
cout << endl;
|
|
}
|
|
}
|
|
|
|
int main(int argc, char * argv[])
|
|
{
|
|
int exit_status(0);
|
|
|
|
try
|
|
{
|
|
CommandLine::get_instance()->run(argc, argv,
|
|
"example_selection", "EXAMPLE_SELECTION_OPTIONS", "EXAMPLE_SELECTION_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()));
|
|
|
|
/* Make some selections, and display what they give. The selection
|
|
* object used determines the number and ordering of results. In the
|
|
* simplest form, it takes a Generator as a parameter. */
|
|
show_selection(env, selection::AllVersionsSorted(
|
|
generator::Matches(make_package_dep_spec({ }).package(
|
|
QualifiedPackageName("sys-apps/paludis")), nullptr, { })));
|
|
|
|
/* Generators can be passed through a Filter. The Selection optimises
|
|
* the code internally to avoid doing excess work. */
|
|
show_selection(env, selection::AllVersionsSorted(
|
|
generator::Matches(make_package_dep_spec({ }).package(
|
|
QualifiedPackageName("sys-apps/paludis")), nullptr, { }) |
|
|
filter::InstalledAtSlash()));
|
|
|
|
/* Filters can be combined. Usually filter::NotMasked should be combined
|
|
* with filter::SupportsAction<InstallAction>, since installed packages
|
|
* aren't masked. */
|
|
show_selection(env, selection::AllVersionsSorted(
|
|
generator::Matches(make_package_dep_spec({ }).package(
|
|
QualifiedPackageName("sys-apps/paludis")), nullptr, { }) |
|
|
filter::SupportsAction<InstallAction>() |
|
|
filter::NotMasked()));
|
|
|
|
/* selection::AllVersionsSorted can be expensive, particularly if there
|
|
* is no metadata cache. Consider using other Selection objects if
|
|
* you only need the best matching or some arbitrary matching ID. */
|
|
show_selection(env, selection::BestVersionOnly(
|
|
generator::Matches(make_package_dep_spec({ }).package(
|
|
QualifiedPackageName("sys-apps/paludis")), nullptr, { }) |
|
|
filter::SupportsAction<InstallAction>() |
|
|
filter::NotMasked()));
|
|
}
|
|
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;
|
|
}
|
|
|
|
|