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/// \file engine/filters.hpp
/// Representation and manipulation of filters for test cases.
///
/// All the filter classes in this module are supposed to be purely functional:
/// they are mere filters that decide whether they match or not the input data
/// fed to them.  User-interface filter manipulation must go somewhere else.

#if !defined(ENGINE_FILTERS_HPP)
#define ENGINE_FILTERS_HPP

#include <string>
#include <set>
#include <utility>

#include "utils/fs/path.hpp"
#include "utils/optional.ipp"


namespace engine {


/// Filter for test cases.
///
/// A filter is one of: the name of a directory containing test cases, the name
/// of a test program, or the name of a test program plus the name of a test
/// case.
class test_filter {
public:
    /// The name of the test program or subdirectory to match.
    utils::fs::path test_program;

    /// The name of the test case to match; if empty, represents any test case.
    std::string test_case;

    test_filter(const utils::fs::path&, const std::string&);
    static test_filter parse(const std::string&);

    std::string str(void) const;

    bool contains(const test_filter&) const;
    bool matches_test_program(const utils::fs::path&) const;
    bool matches_test_case(const utils::fs::path&, const std::string&) const;

    bool operator<(const test_filter&) const;
    bool operator==(const test_filter&) const;
    bool operator!=(const test_filter&) const;
};


/// Collection of user-provided filters to select test cases.
///
/// An empty collection of filters is considered to match any test case.
///
/// In general, the filters maintained by this class should be disjoint.  If
/// they are not, some filters may never have a chance to do a match, which is
/// most likely the fault of the user.  To check for non-disjoint filters before
/// constructing this object, use check_disjoint_filters.
class test_filters {
    /// The user-provided filters.
    std::set< test_filter > _filters;

public:
    explicit test_filters(const std::set< test_filter >&);

    /// Return type of match_test_case.  Indicates whether the filters have
    /// matched a particular test case and, if they have, which filter did the
    /// match (if any).
    typedef std::pair< bool, utils::optional< test_filter > > match;

    bool match_test_program(const utils::fs::path&) const;
    match match_test_case(const utils::fs::path&, const std::string&) const;

    std::set< test_filter > difference(const std::set< test_filter >&) const;
};


void check_disjoint_filters(const std::set< test_filter >&);


/// Tracks state of the filters that have matched tests during execution.
class filters_state {
    /// The user-provided filters.
    test_filters _filters;

    /// Collection of filters that have matched test cases so far.
    std::set< test_filter > _used_filters;

public:
    explicit filters_state(const std::set< test_filter >&);

    bool match_test_program(const utils::fs::path&) const;
    bool match_test_case(const utils::fs::path&, const std::string&);

    std::set< test_filter > unused(void) const;
};


}  // namespace engine

#endif  // !defined(ENGINE_FILTERS_HPP)